GB2621892A

GB2621892A - An apparatus for treatment of a condition of a nerve and a method for targeting a nerve for subsequent treatment

Info

Publication number: GB2621892A
Application number: GB2212456.4A
Authority: GB
Inventors: Fossum Bratbak Daniel
Original assignee: St Olavs Hospital Trondheim Univ Hospital; Norwegian University of Science and Technology NTNU
Current assignee: St Olavs Hospital Trondheim Univ Hospital; Norwegian University of Science and Technology NTNU
Priority date: 2022-08-26
Filing date: 2022-08-26
Publication date: 2024-02-28
Also published as: GB202212456D0; WO2024042216A1

Abstract

The apparatus comprises a surgical navigation system 1, a cryogenic surgical intervention device 11 adapted to cryoneurolyse the nerve 2 and a detector 5 configured to detect a position of the intervention device. A computer processor reconciles an MRI image of the patient with the anatomy of the patient. The processor is configured to track the position of the intervention device and a display 3 displays the position of the device 11 relative to the nerve. In use, this permits an interventionist to direct the intervention device to the nerve such that said nerve can be cryoneurolysed.

Description

AN APPARATUS FOR TREATMENT OF A CONDITION OF A NERVE AND A METHOD FOR TARGETING A NERVE FOR SUBSEQUENT TREATMENT

The present invention relates to an apparatus for treatment of a condition of a nerve in a head, neck or back of a patient. The present invention also extends to a method of targeting a nerve in a head, neck or back of a patient. The invention further extends to a computer programme product that permits the method to be carried out when executed on a surgical navigation system.

Various conditions, such as pain conditions (e.g. neuralgias), can afflict nerves within the head, neck or back. Such conditions can be extremely painful and disruptive to a person's life, particular where these conditions are chronic or recurrent.

One common type of neuralgia affects the trigeminal nerve, a predominantly sensory nerve, and is termed trigeminal neuralgia. Trigeminal neuralgia is characterised by recurrent brief episodes of unilateral electric shock-like pains in the distribution of one or more divisions of the trigeminal nerve that typically are triggered by innocuous stimuli such as eating or talking. It has been described as one of the most painful conditions known to man. Trigeminal neuralgia has an overall prevalence of approximately 0.13-0.3 % of the world's population. Annual incidence of trigeminal neuralgia is thought to be between 5 to 27 per 100,000.

Most cases of trigeminal neuralgia begin for persons aged 50 and over. Given that, proportionally, this is an increasing population worldwide, incidence rates of trigeminal neuralgia are expected only to increase.

First-line therapy for trigeminal neuralgia is typically pharmacological.

Carbamazepine, oxcarb, gabapentin and other CNS depressants are conventionally used, but about 50% of patients do not respond or at least do not respond satisfactorily to pharmacological treatment. Pharmacological treatment is also associated with a number of adverse side effects including: drowsiness, dizziness, skin rash, liver damage and ataxia.

For pharmacological refractory patients, the fall-back treatment option for trigeminal neuralgia is a complex and non-insignificant neurosurgical intervention: microvascular decompression. In 50% of cases microvascular decompression will result in complete remission of trigeminal neuralgia; however, in the other 50% of cases patients will typically see symptoms recur after 5 years.

Microvascular decompression for treatment of trigeminal neuralgia is associated with a significant risk to life (mortality of 0.5%). It is also associated with serious adverse side effects, including the onset of neurological complications (e.g. infarction, hematoma and cerebrospinal fluid leaks) in approximately 4% of cases Adverse side effects also extend to hearing and sensory losses. Such a neurosurgical intervention is also costly, with cost approximately in the region of $30,000-$40,000 USD. Moreover, for older patients (i.e. those most susceptible to trigeminal neuralgia), surgical intervention is often not suitable given the risks involved. Microvascular decompression techniques also offer poor repeatability of treatment as the build-up of scar tissue formed from the intervention can prevent access to the treatment site repeatedly and, moreover, major surgical interventions of this type take a significant toll on the body. Thus, there are significant disadvantages associated with microvascular decompression as a treatment regime for trigeminal neuralgia.

For those patients for whom microvascular decompression is not available/suitable, percutaneous intervention techniques have been proposed and utilised, albeit rarely. These techniques involve destruction of the trigeminal nerve, or at least a relevant branch/portion thereof, via alcohol injection, balloon compression or radio frequency thermocoagulation. These techniques have however not gained any particular traction for trigeminal neuralgia treatment, not least given the adverse associated side effects. In particular, such percutaneous treatments have resulted in a significant number of patients experiencing sensory loss, corneal numbness and/or anaesthesia dolorosa (a severe and untreatable pain condition).

Accordingly, improvements that permit and allow for improved treatment of trigeminal neuralgia and, more generally, conditions afflicting nerves are desired. According to a first aspect, there is provided a method of targeting a nerve in a head, neck or back of a patient using a surgical navigation system, the method comprising: providing a cryogenic surgical intervention device, wherein the cryogenic surgical intervention device is adapted to cryoneurolyse the nerve in the head, neck or back of the patient; detecting, using a detector of the surgical navigation system, a position of the cryogenic surgical intervention device; reconciling, using a computer processor of the surgical navigation system, an MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient; determining and tracking, using the computer 3 -processor, a position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; and displaying, using a display, the position of the surgical intervention device relative to the nerve in the head, neck or back; wherein the displayed position of the surgical intervention device relative to the nerve in the head, neck or back is configured to permit an interventionist to direct the cryogenic surgical intervention device to the nerve in the head, neck or back such that said nerve can be cryoneurolysed.

Cryoneurolysis is a technique where nerves are frozen, e.g. with a probe or needle, causing Wallerian degeneration of the nerve. Wallerian degeneration results in the destruction of the axons of the nerve and the encasing myelin sheath; however the surrounding endoneurium tubes, perineurium and epineurium remain intact during Wallerian degeneration. Given that these structures remain intact after freezing, the axons and myelin are able to regenerate and thereby permit the nerve to regain function.

Cryoneurolysis thus provides a reversible block to the functioning of the nerve since the nerve will eventually regenerate. The duration of the reversible block depends on the distance between the point of application of cryoneurolysis treatment and the nerve endings. Nerves will regenerate at a speed of approximately 1-2 mm per day and even after regeneration may take far longer to regain full function. As such, conditions (e.g. pain conditions) of nerves can be blocked, albeit reversibly using cryoneurolysis.

The invention of the first aspect is advantageous since it permits for later cryoneurolyfic treatment of conditions afflicting nerves and does so in a targeted manner by virtue of the use of the surgical navigation system, which permits a longer lasting and more effective block to the afflicting condition to be provided and further results in fewer adverse side effects experienced by the patient.

An alternative approach to treatment of conditions afflicting a nerve in the head, neck or back, e.g. trigeminal neuralgia, might comprise cryoneurolysis performed in a conventional open-surgery setting. Cryoneurolysis applied in this manner however (i.e. via an open-surgical technique, without the aid of a surgical navigation system) is disadvantageous, in particular when compared to treatment that would be permitted by the method of the first aspect of the invention. This is because such an approach relies on a visual inspection of and open-surgical access to the relevant nerve by the surgical interventionist. As such, only very distal/peripheral/superficial portions of the afflicted nerve are accessible, which has 4 -the result that the effect of the pain block is relatively short lived (expected to be approximately 4 months). Migration of the pain from one distal branch to other distal branches of the trigeminal nerve may also be expected to occur as a result of treating only the distal portion of the nerve.

Further, the requirement for open-surgery under this alternative approach would mean that the treatment would be associated with inherent mortality risks and expense. Moreover, such an alternative approach would be associated with poor repeatability given the inevitable formation of scar tissue from the invasive surgery that would be required, which would prevent the target site being accessed again, and which does not align well with the need for repetition given the short-lived pain block provided.

In contrast, since the invention of the first aspect avails of surgical navigation based on MRI images, an interventionist is subsequently permitted to access optionally deeper (i.e. non-peripheral/ non-superficial) portions of the nerve to provide a longer-term pain block to the nerve. Moreover, the MRI surgical navigation system forming the basis of the first aspect of the invention permits for the subsequent intervention with the cryogenic intervention device to be carried out relatively non-invasively (e.g. through a percutaneous or trans-oral approach as discussed further below). The interventionist is not reliant on a visual approach to the nerve as would be the case in the above discussed alternative approach. Thus, given the method of the first aspect does not necessitate a subsequent open-surgical procedure, the subsequent procedure can be done very much less invasively than in the discussed alternative approach. Hence, the method of the first aspect permits for improved repeatability of treatment since the build-up of scar tissues can be avoided and can permit the avoidance of potential adverse effects associated with open surgical techniques.

As will be clear from the above, the method of the first aspect stops short of any surgical or therapeutic intervention on the patient. As such, the method of the first aspect does not comprise any surgical or therapeutic step. The method of the first aspect merely results in a targeting of a nerve in a head, neck or back of a patient such that an interventionist can, at a subsequent point in time (and falling outside of the scope of the method of the first aspect), direct the cryogenic intervention device to the nerve in the head, neck or back and carry out cryoneurolysis of the nerve. The method of the first aspect can therefore be considered a method of guiding a surgical interventionist to an intended target site,

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but the actual surgical intervention and cryoneurolysing does not form part of the scope of the first aspect of the invention.

The term 'surgical navigation system' as used herein may refer to a system that enables an interventionist to direct a device toward a target site or structure in the human body of a subject/patient by detecting the relative position between a physical subject/patient and medical images of the same subject/patient.

The method may comprise detecting, using the detector of the surgical navigation system, a reference marker of the surgical navigation system that is fixed relative to the anatomy of the patient. The step of reconciling, using the computer processor of the surgical navigation system, an MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient may hence comprise reconciling, using a computer processor of the surgical navigation system, the detected position of the reference marker with the MRI image.

Reconciling an MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient may mean mapping, transposing, calibrating, connecting, superimposing and/or overlaying the MRI image with the actual (and relevant/pertinent) anatomical features of the patient.

The surgical navigation system may comprise a memory (e.g. random-access memory, read-only memory, a magnetic storage device, a semiconductor storage device. HDD, SSD, compact disk etc.). The memory may be in communication with the computer processor. The MRI image of the anatomy of the patient may be stored on the memory. The method may comprise, prior to the step of reconciling the MRI image of the anatomy of the patient showing the nerve in the head, neck or back, communicating the MRI image of the anatomy of the patient from the memory to the processor.

The processor and/or the memory may be remote from or local the other components of the surgical navigation system (e.g. the display, the optional reference marker, etc.). In scenarios where the processor and/or the memory are remote from the other components of the surgical navigation system, the processor and/or memory may communication with the other components of the surgical navigation system via an appropriate wireless communication network (e.g. via Bluetooth, Wi-Fi, LoRa, 3G, 4G, etc.). For example, the processor may be in wireless communication with the display and/or the processor may be in wireless communication with the optional memory. 6 -

The targeted nerve may be a predominantly sensory nerve. A predominantly sensory nerve in the context of the invention is a nerve that predominantly (i.e. in the majority, optionally the vast majority, further optionally exclusively) carries sensory nerve fibres. As is well known, nerves can comprise sensory, motor and/or autonomic nerve fibres, with many nerves being formed from a mixture of such fibres. Certain nerves and/or certain portions of nerves will be dominated by (or even exclusively consist of) one of these types of fibres. For example, certain nerves, such as the facial motor nerves, will be dominated by motor nerve fibres and as such would be termed a predominantly motor nerve. The invention of the first aspect may optionally comprise targeting a predominantly sensory nerve -i.e. a nerve or portion of a nerve that comprises in the majority/is dominated by sensory nerve fibres.

For predominantly sensory nerves, in the event of an inadvertent (i.e. unavoidable) denervation of motor or autonomic fibres in said predominantly sensory nerve, there would be no clinically significant adverse effects experienced, or at least no adverse effects experienced that would not outweigh a positive treatment response.

Alternatively, the targeted nerve may be a predominantly autonomic nerve. A predominantly autonomic nerve in the context of the invention is a nerve that predominantly (i.e. in the majority, optionally the vast majority, further optionally exclusively) carries autonomic nerve fibres. The invention of the first aspect thus may optionally comprise targeting a predominantly autonomic nerve -i.e. a nerve or portion of a nerve that comprises in the majority/is dominated by autonomic nerve fibres. By targeting an autonomic nerve, an autonomic block to a condition, e.g. a headache (more on this below) may be subsequently provided.

The predominantly autonomic nerve may be pterygopalatine nerve. Parasympathetic nerve fibres emerge from the vidian foramen and synapse in the sphenopalatine ganglion before sending off post ganglionic nerve fibres along the pterygopalatine nerve to innervate intracranial nerve structures involved in headache. As such, by targeting a pterygopalatine nerve in the method of the first aspect, a subsequent autonomic block to headaches can be provided.

As noted above, the method of the first aspect allows for targeting of various different potions of the nerves, such as more proximal/deeper portions of the nerves, to permit a longer term of treatment. This is not possible in prior art 7 -techniques or in the alternative proposed approach discussed above since surgical navigation is required to target these deeper/ more proximal portions of the nerves. For example, targeting the nerve may comprise targeting a deep sensory nerve segment of the nerve, wherein the MRI image shows the deep sensory nerve segment of the nerve, wherein the position of the surgical intervention device is determined and tracked relative to the deep sensory nerve segment, wherein the position of the surgical intervention device is displayed relative to the deep sensory nerve segment, and wherein the displayed position is configured to permit an interventionist to direct the cryogenic intervention device to the deep sensory nerve segment.

The deep sensory nerve segment may be a proximal sensory nerve segment and/or a non-peripheral/ non-superficial nerve segment.

The deep sensory nerve segment may be a nerve segment that cannot be directly and/or reliably identified with one, more or all of: ultrasound (US) imaging, computerised tomography (CT) imaging, fluoroscopy or visually.

The deep sensory nerve segment may not be directly and/or reliably identifiable with CT imaging or fluoroscopy when it is situated sufficiently far away from a bone/bony landmark that would be visible on a CT image and may otherwise act as a reference for locating a nerve segment. It will be apparent to the skilled person what is meant by sufficiently far away' in this context.

The deep sensory nerve segment may not be directly and/or reliably identifiable with US imaging when it is situated sufficiently deeply/proximally/nonsuperficially (i.e. spaced sufficiently far away from the skin) such that it cannot be identified on a US image. Again, it will be apparent to the skilled person what is meant by 'sufficiently deeply/proximally/non-superficially' in this context.

The deep sensory nerve segment may not be directly and/or reliably identifiable visually when it cannot be seen to the eye, even with an open surgery technique, without significant risk for adverse events. This may be because it is positioned too deeply/proximally and/or because the patient's anatomy occludes any possible view of it.

The deep sensory nerve segment may be a periforaminal nerve segment. The periforaminal nerve segment may be a nerve segment that is situated within 7 cm of a base of the skull of the patient and/or within 7 cm of a vertebral foramen/foramina. The periforaminal nerve segment may be a neural structure 8 -exiting any opening in a bone or between bones (e.g. foramina, fissures and canals carrying neural structures) The deep sensory nerve segment may be an intermediate portion of the nerve. That is to say, it may be a portion of the nerve spaced from both the superficial end of the nerve and spaced from a proximal, originating branch of the nerve. Such an intermediate portion of the nerve may be a predominantly sensory nerve portion spaced from any predominantly motor and/or autonomic nerves and/or comprise few motor and/or autonomic nerve fibres such that any adverse effects through cryoneurolysis of motor and/or autonomic nerve (fibres) can be reduced or totally avoided. Alternatively, such an intermediate portion of the nerve may be a predominantly autonomic nerve portion spaced from any predominantly motor and/or sensory nerves and/or comprise few motor and/or sensory nerve fibres such that any adverse effects through cryoneurolysis of motor and/or sensory nerve (fibres) can be reduced or totally avoided.

Targeting a deep sensory nerve segment such that an interventionist can subsequently cryoneurolyse said deep sensory nerve segment is advantageous since it provides for a longer block to the nerve. As noted above, cryoneurolysis results in Wallerian degeneration of the nerve from the point of application of cryoneurolysis up to the nerve ending at its most peripheral point. The nerve then subsequently regenerates at a speed of approximately 1-2 mm per day. Thus, by cryoneurolysing the nerve at a deeper portion the time for regeneration is made longer since a greater length of nerve is required to regenerate before sensory function is regained. In that way, the nerve block can be made longer as compared to, e.g., the alternative approach discussed above based on cryoneurolysis techniques where only a very peripheral portion of the nerve can be targeted and hence only a very short block is provided. It is estimated that by cryoneurolysing deep sensory nerve segments a block to the nerve of 12 months (or longer) may be affected. Moreover, by cryoneurolysing deep sensory nerve segments, the likelihood of pain migration to other sensory nerves is lessened as compared to cryoneurolysing peripheral nerve segments where pain migration to other nerves can occur.

It is not required however to target deep sensory nerve segments, and the method of the first aspect can be applied to targeting peripheral/superficial nerve segments. 9 -

The nerve may be a cranial nerve. The cranial nerve may be a glossopharyngeal nerve or a petrosal nerve (e.g. deep petrosal nerve, greater petrosal nerve, or lesser petrosal nerve). Each of the deep petrosal nerve, the greater petrosal nerve, and the lesser petrosal nerve are predominantly autonomic nerves. The cranial nerve may be a vagus nerve. As noted above, the cranial nerve may be a pterygopalatine nerve. The method may be for targeting any one of these nerves such that an interventionist can subsequently treat a condition, such as a pain condition (e.g. neuralgia), afflicting any of these nerves.

The cranial nerve may be a trigeminal nerve. As discussed at length above, trigeminal neuralgia is a pain condition afflicting a great number of the population. Thus, the method of the first aspect may comprise targeting the trigeminal nerve with a view to allowing an interventionist to later treat trigeminal neuralgia (and/or any other pain condition/neuralgia afflicting the trigeminal nerve) through cryoneurolysing the nerve with the cryogenic surgical intervention device.

The method may comprise targeting the mandibular nerve (V3) of the trigeminal nerve. The mandibular nerve is a branch of the trigeminal nerve. 30% of trigeminal neuralgia patients experience pain associated with the mandibular nerve (V3), another 30% of trigeminal neuralgia patients experience pain associated with the mandibular nerve and the maxillary nerve (V2), and 5% of trigeminal neuralgia patients experience pain associated with both the ophthalmic nerve (V1) and at least one of the maxillary nerve and the mandibular nerve. Thus, it is particularly beneficial to be able to target the mandibular nerve since it allows an interventionist to subsequently treat (at least in part) trigeminal neuralgia for up to 65% of patients.

The method may comprise targeting a deep sensory nerve segment of the mandibular nerve. The deep sensory nerve segment of the mandibular nerve may be an intermediate portion of the mandibular nerve. The proximal and the distal ends of the mandibular nerve are a mixed nerve (comprising both motor and sensory nerve fibres); however, the intermediate portion is predominantly sensory and thus it is particularly advantageous to target this region for later cryoneurolysis.

It is not at all possible to target the intermediate portion of the mandibular nerve with ultrasound imaging, CT imaging or fluoroscopy. As such, the use of MRI imaging provides a particularly beneficial synergistic effect since it permits targeting of this desired portion of the mandibular nerve.

The method may comprise targeting the auriculotemporal nerve of the mandibular nerve. The auriculotemporal nerve is an entirely sensory branch of the -10 -mandibular nerve which may be afflicted by a neuralgia or pain condition (e.g. trigeminal neuralgia) and is therefore particularly beneficial to treat. The auriculotemperoral nerve is a deep sensory nerve segment of the trigeminal nerve and, more specifically, is an intermediate portion of the trigeminal nerve.

The method may comprise targeting the mandibular nerve (V3) at the interpterygoid space. The interpterygoid space refers to a region bounded by the pterygoid muscles (i.e. the lateral (external) pterygoid muscle and internal medial pterygoid muscle). This space comprises a high degree of sensory branches and peripheral branches of the mandibular nerve. As such, the branches of the trigeminal nerve in the interpterygoid space is a highly effective place to treat pain condifions/neuralgias given the high degree of sensory nerves and absence or low number of motor and autonomic nerves there. The nerve branches found at the interpterygoid space are/form an intermediate portion of the trigeminal nerve, more specifically an intermediate portion of the mandibular nerve branch. Thus, the nerve branches at the interpterygoid space are deep sensory nerve segments.

The method may comprise targeting the buccal nerve, the lingual nerve and/or the inferior alveolar nerve. The buccal nerve, the lingual nerve and the inferior alveolar nerve are branches of the mandibular nerve. They run through the interpterygoid space and thus the method may comprise targeting the buccal nerve, the lingual nerve and/or the inferior alveolar nerve in the interpterygoid space. The buccal nerve, the lingual nerve and/or the inferior alveolar nerve are each predominantly sensory nerves.

The method may comprise targeting the maxillary nerve (V2) of the trigeminal nerve. The maxillary nerve is a branch of the trigeminal nerve. 30% of trigeminal neuralgia patients experience pain associated with the maxillary nerve, another 30% of trigeminal neuralgia patients experience pain associated with the mandibular nerve and the maxillary nerve, and 5% of trigeminal neuralgia patients experience pain associated with both the ophthalmic nerve (V1) and at least one of the maxillary nerve and the mandibular nerve. Thus, it is particularly beneficial to be able to target the maxillary nerve since it allows an interventionist to subsequently treat (at least in part) trigeminal neuralgia for up to 65% of patients. The method may comprises targeting a deep sensory segment, optionally an intermediate portion of the maxillary nerve.

The method may comprise targeting the maxillary nerve as it emerges from the skull. This is advantageous since any subsequent cryoneurolysis at this target site will provide a significant length of pain block.

The method may comprise targeting the maxillary nerve via the foramen rotundum. At the foramen rotundum, a deep sensory nerve segment, in particular an intermediate portion of the maxillary nerve/trigeminal nerve is present, which as above is desirable portion of the nerve to target and subsequently treat. At the foramen rotundum, the maxillary nerve is isolated and separated from other nerves, and in particular other motor and autonomic nerves and thus there is low risk in any subsequent treatment of adverse effects resulting from cryoneurolysis of the wrong nerve/ wrong nerve fibres.

The method may comprises targeting the ophthalmic nerve (V1) of the trigeminal nerve. The ophthalmic nerve is a branch of the trigeminal nerve. 5% of trigeminal neuralgia patients experience pain associated with the maxillary nerve and 5% of trigeminal neuralgia patients experience pain associated with both the ophthalmic nerve and at least one of the maxillary nerve and the mandibular nerve. Thus, targeting the ophthalmic nerve is beneficial since it allows an interventionist to subsequently treat (at least in part) trigeminal neuralgia for up to 10 % of patients.

The method may comprises targeting a deep sensory segment, optionally an intermediate portion of the maxillary nerve.

The method may comprise targeting the frontal nerve, the supratrochlear nerve and/or the supraorbital nerve of the ophthalmic nerve. The supratrochlear nerve and/or the supraorbital nerve are predominantly sensory nerve branches of the ophthalmic nerve that are at an intermediate portion of the maxillary nerve/trigeminal nerve and thus are deep sensory nerve segments.

As above however, the invention is not limited to targeting the trigeminal nerve or even cranial nerves. The method is equally applicable to targeting nerves in the neck and back also. For example, the nerve may be a spinal nerve or spinal nerve branch. The spinal nerve or spinal nerve branch may be an occipital nerve.

The spinal nerve or spinal nerve branch may be one of: a greater occipital nerve, a lesser occipital nerve, a third occipital nerve, a Cl vertebrae spinal nerve, a 02 spinal nerve, a 03 spinal nerve, any spinal nerve between and including the Cl spinal nerve to the coccygeal nerve, a posterior (dorsal) ramus of a spinal nerve, a medial branch of a posterior (dorsal) ramus, a lateral branch of a posterior (dorsal) -12 -ramus, a meningeal branch (e.g. recurrent meningeal or sinuvertebral nerves) or a cervical plexus (superficial, intermediate and/or deep).

Occipital neuralgia is another common and severe pain condition afflicting a great number of the population. Thus, the method of the first aspect may comprise targeting an occipital nerve with a view to allowing an interventionist to later treat occipital neuralgia (and/or any other pain condition/neuralgia afflicting the occipital nerve) through cryoneurolysing the nerve with the cryogenic surgical intervention device.

The spinal nerve may be any one of the 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal nerves The cryogenic surgical intervention device may comprise a cryogenic probe (sometimes termed tryoprobe') configured to cryoneurolyse the nerve in the head, neck or back.

The cryogenic surgical intervention device may comprise a cryogenic needle (sometimes termed tryoneedle) configured to contact and cryoneurolyse the nerve in the head, neck or back.

The cryogenic surgical intervention device, either wholly or partly, may be reusable such that it can be used for multiple cryoneurolysis procedures, optionally on multiple different patients. As an example, the cryogenic surgical intervention device may be entirely reusable other than for the needle/probe, which is single use and/or intended to be disposed of after use. A new needle/probe may then replace the previous needle/probe for a subsequent use of the cryogenic surgical intervention device.

Alternatively, the cryogenic surgical intervention device may entirely single use and/or intended for disposal after a single use.

A portion of the cryogenic surgical intervention device that is adapted to be inserted into a patient (e.g. the needle/probe) may be suitably thin/small such that, when used in a cryoneurolysis process, collateral trauma/damage to surrounding tissue in the patient is minimised. For example, the portion of the cryogenic surgical intervention device that is adapted to be inserted into a patient (e.g. the needle/probe) may be 25 gauge or smaller. Such a size of device is particularly suited for outpatient settings and/or for percutaneous, transoral or transmucosal approaches as discussed further below.

The cryogenic surgical intervention device (e.g. the needle and/or probe) may be specifically shaped, sized and/or configured to reach one or more of the -13 -specific target sites as discussed above. For example, the cryogenic need/probe may have a length, diameter, curvature, and/or aperture position or aperture positions that make it specifically configured for targeting a given target site.

The cryogenic surgical intervention device may comprise a guide configured to guide the needle/probe to a specific target site. The cryogenic surgical intervention device may comprise a plurality of such guides, each guide being specifically configured to direct the needle/probe to a respective, specific target site.

The guide(s), needle and/or probe may be patient-specific or patient generic. That is, the guide(s), needle and/or probe may be tailor-made and manufactured for a specific patient based on, e.g., MRI imaging data or the guide(s), needle and/or probe may not be tailor-made/ patient specific.

The cryogenic surgical intervention device may comprise a cannula configured for connection to a source of a pressurised cryogenic gas (e.g. cryogenic gas at 800 bar). The cannula may extend through the surgical intervention device to a distal end of the device (e.g. the cannula may extend through the needle/probe to a distal end, e.g. a tip, of the needle/probe). The distal end may be a working end of the device, which is an end configured to reach cryogenic temperatures and to contact the nerve to thereby cryoneruloyse it. The cannula may comprise an aperture at the distal end of the device. The aperture may be configured to permit the pressurised cryogenic gas passing therethrough to exit the cannula and to expand rapidly once it exits the cannula. This rapid expansion of the pressurized cryogenic gas may, under the Joule Thomson effect, be configured to cause a rapid decrease in temperature of the distal end of the device to cryogenic temperatures. This rapid decrease in temperature may be configured to cause an ice ball to form at an exterior of the distal end of the cryogenic surgical intervention device. Once at a cryogenic temperature, the distal end of the device (e.g. tip of the probe/needle) can be used to cryoneruolyse a nerve.

The distal end of the device (e.g. the tip of the probe/needle) may have a shape and/or dimension that causes a specific shape of ice ball to form thereat when the rapid decrease in temperature occurs. The specific shape of the ice ball may be one that is particularly suited for cryoneurolysis of the desired target site.

The aperture and/or cannula, optionally in combination with the shape and/or dimension of the distal end of the device, may comprise a shape and/or dimension that causes a specific shape of ice ball to form thereat when the rapid -14 -decrease in temperature occurs. The specific shape of the ice ball may be one that is particularly suited for cryoneurolysis of the desired target site.

The aperture and/or cannula may be arranged relative to the distal end of the device to cause a specific shape of ice ball to form thereat when the rapid decrease in temperature occurs. The specific shape of the ice ball may be one that is particularly suited for cryoneurolysis of the desired target site.

The distal end of the device, the aperture and/or the cannula may be configured to cause a plurality of ice balls to form at an exterior of the distal end of the cryogenic surgical intervention device when the rapid decrease in temperature occurs.

The cryogenic surgical intervention device may comprise an ampulla arranged to be filled with the pressurised cryogenic gas. Thus, the ampulla may act as the source of pressurised cryogenic gas. The ampulla may be in the form of a cartridge. The ampulla may be replaceable, e.g. a replaceable cartridge.

The cryogenic surgical intervention device may be a console independent, handheld device. That is, the cryogenic surgical intervention device may be entirely independently contained and may not rely on, e.g., an external source of cryogenic gas etc. This may be made possible through use of the cryogenic gas ampulla as discussed above. A console independent, handheld device is particularly advantageous in an outpatient scenario (discussed further below) Alternatively, the cryogenic surgical intervention device may be connected to a console, e.g., via suitable cabling and/or conduits. The console may comprise a source of cryogenic gas.

The cryogenic surgical intervention device may be configured for use in an open-surgical context. Alternatively, and advantageously, the cryogenic surgical intervention device is configured to be directed to the nerve in the head, neck or back such that said nerve can be cryoneurolysed via a procedure that is minimally invasive, e.g. via a percutaneous, transoral and/or transmucosal approach. A cryogenic surgical device configured to be directed in this/these ways is advantageous since any subsequent cryoneurolysis is kept minimally invasive.

Thus, the risks associated with the subsequent intervention are minimized and the build-up of scar tissue is also minimised. As such, the cryogenic surgical intervention device may be used safely and repeatedly for cryoneurolysis.

The cryogenic surgical intervention device may be adapted for use in an out-patient setting. This is particularly the case where the cryogenic surgical -15 -intervention device is configured to be directed to the nerve in the head, neck or back such that said nerve can be cryoneurolysed via a percutaneous, transoral and/or transmucosal approach. That is to say that the cryogenic surgical intervention device may be suitably and safely directed to the nerve in the head, neck or back without requiring a surgical theatre, operating room etc. The surgical navigation system may be based on light (e.g. infrared), sound waves or magnetic fields. That is to say, the step of detecting the position of the cryogenic surgical intervention device and/or the optional step of detecting the reference marker may comprise detecting with light (e.g. infrared), sound waves or magnetic fields that are emitted and/or reflected from the marker and/or the cryogenic surgical intervention device. As such, the detector may be a light detector (e.g. an optical or infrared camera), a sound detector or a detector of magnetic fields.

The surgical navigation system may be based on electromagnetic navigation, video-based navigation (e.g. may comprise use of virtual reality) or any other suitable modality.

The surgical navigation system may comprise a plurality of detectors. The detectors may be positioned at different positions in space so as to permit the most accurate, reliably and precise detection of the cryogenic surgical intervention device and, optionally, the reference marker.

As noted above, the step of detecting the position of the cryogenic surgical intervention device and/or the optional step of detecting the reference marker may comprise detecting with light (e.g. infrared), sound waves or magnetic fields that are emitted and/or reflected from the cryogenic surgical intervention device and/or the optional reference marker.

Where emitted, the cryogenic surgical intervention device and/or the optional reference marker may comprise a suitable emitter (e.g. sound emitter, a light (e.g. LED, optionally an infrared LED) or an electromagnetic emitter). The method may comprise, preceding the step or steps of detecting, the step of emitting light (e.g. infrared), sound waves or a magnetic field from the emitter(s).

Where reflected, the cryogenic surgical intervention device and/or the optional reference marker (or at least a component/portion thereof, such as a marker or markers -see discussion below) may be specifically adapted to reflect light (e.g. infrared), sound waves or magnetic fields. For example, the optional reference marker may comprise one or a plurality of optically detectable spheres.

-16 -Where there is a plurality of optically detectable spheres, these may be arranged as part of a navigation array, wherein the optically detectable spheres are fixedly positioned relative to one another in an irregular manner. The method may comprise, preceding the step or steps of detecting, reflecting light (e.g. infrared), a sound wave or a magnetic field from the cryogenic surgical intervention device and/or the optional reference marker. Preceding the step(s) of reflecting, the method may comprise emitting, from one or more emitters of the surgical navigation system light (e.g. infrared, for example an infrared light), sound waves or a magnetic field.

The cryogenic surgical intervention device may have a marker (e.g. an optically detectable sphere) fixedly mounted thereto or comprised integrally therewith. The step of detecting, using the detector, a position of the cryogenic surgical intervention device may comprise detecting the marker of the cryogenic surgical intervention device. The cryogenic surgical intervention device may comprise integrally/ have mounted thereto a plurality of such markers (e.g. a plurality of optically detectable spheres), optionally arranged as part of a navigation array, wherein the plurality of markers are fixedly positioned relative to one another in an irregular manner. The marker(s) may (each) have a fixed and known spatial and angular relationship with the rest of the cryogenic surgical intervention device, for example a known and fixed spatial and angular relationship with a tip of a probe/needle of the device. In that way a position of a working end/distal end/ portion adapted to be inserted into a patient/needle/probe of the device can be (indirectly) detected.

In a second aspect of the invention, there is provided an apparatus for treatment of a condition of a nerve in a head, neck or back of a patient, the apparatus comprising: a cryogenic surgical intervention device, wherein the cryogenic surgical intervention device is adapted to cryoneurolyse the nerve in the head, neck or back; and a surgical navigation system comprising: a detector configured to detect a position of the cryogenic surgical intervention device; a computer processor configured to reconcile an MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient; wherein the computer processor is further configured to determine and track a position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; and a display configured to display the position of the surgical intervention device relative to the nerve in the head, neck or back as depicted in the -17 -MRI image; and wherein based on a displayed position of the surgical intervention device relative to the nerve in the head, neck or back, the surgical navigation system permits an interventionist to direct the cryogenic surgical intervention device to the nerve in the head, neck or back to thereby cryoneurolyse said nerve.

The apparatus of the second aspect may be utilized to carry out the method of the first aspect, optionally in any optional form thereof. As such, the apparatus of the second apparatus may be configured to carry out the method of the first aspect, optionally in any optional form thereof. Thus, the apparatus of the second apparatus may be configured for treatment of a condition afflicting any one of the nerves/ nerve portions discussed above in relation to the first aspect.

The surgical navigation system and/or the cryogenic surgical intervention device of the second aspect may be in accordance with the corresponding features described above with reference to the first aspect, and may optionally include or be in accordance with any optional features thereof. For example, the cryogenic surgical intervention device may comprise a cryoneedle or a cryoprobe that is adapted to cryoneurolyse the predominantly sensory nerve in the head, neck or back.

The surgical navigation system may comprise a reference marked adapted to be fixed relative to the anatomy of the patient, wherein the detector is configured to detect the reference marker, and wherein the computer processor is configured to reconcile the detected position of the reference marker with the MRI image to thereby reconcile the MRI image with the anatomy of the patient.

The apparatus may be for treatment of a pain condition. The pain condition may be at least one of a headache, trigeminal pain, a neuralgia, facial pain, neck pain, thoracic pain, lumbar pain, sacral pain and coccygeal pain. Further details of the pain condition that the apparatus may be suitable for treating are set out below. The apparatus may be for treatment of a condition of a trigeminal nerve, e.g. as discussed above in relation to the first aspect of the invention. The apparatus may be for treatment of trigeminal neuralgia.

The apparatus may be for treatment of a condition of an occipital nerve, e.g. as discussed above in relation to the first aspect of the invention. The apparatus may be for treatment of occipital neuralgia.

The apparatus may comprise a cryogenic surgical intervention device that is adapted to cryoneurolyse a deep sensory nerve segment of the nerve. The MRI image may show the deep sensory nerve segment of the nerve. The processor may -18 -be configured to determine and track the position of the surgical intervention device relative to the deep sensory nerve segment. The display may be configured to display the position of the surgical intervention device relative to the deep sensory nerve segment. The displayed position may permit an interventionist to direct the cryogenic surgical intervention device to the deep sensory nerve segment.

In a third aspect of the invention, there is provided, a computer programme product comprising instructions that when executed on a computer processor of a surgical navigation system, will configure the surgical navigation system to: detect, using the detector, a position of a cryogenic surgical intervention device, wherein the cryogenic surgical intervention device is adapted to cryoneurolyse the nerve in the head, neck or back of the patient; reconcile an MRI image of the anatomy of the patient showing a nerve in the head, neck or back with the anatomy of the patient; determine and track a position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; display, using a display of the surgical navigation system, the position of the surgical intervention device relative to nerve in the head, neck or back; and guide, using the display, an interventionist in directing the cryogenic intervention device to the nerve in the head, neck or back such that said nerve can be cryoneurolysed.

The computer programme product of the third aspect may be executed on the surgical navigation system of the second aspect, optionally in any optional form thereof.

It will be noted that the computer programme product configures the surgical navigation system to carry out steps correspondent to those comprised as part of the first aspect of the invention. The computer programme product may hence be used to carry out those correspondent steps of the method of the first aspect. The computer programme product may equally comprise instructions that when executed on a computer processor of a surgical navigation system will configure the surgical navigation system to carry out any of the (optional) functionality of the surgical navigation system described above in relation to the first aspect of the invention.

In a fourth aspect of the invention, there is provided a method of treating a condition of a nerve in a head, neck or back of a patient, the method comprising targeting the nerve in the head, neck or back of a patient with an MRI image based surgical navigation system, and cryoneurolysing the nerve in the head, neck or back of the patient with a cryogenic surgical intervention device.

-19 -The method of the fourth aspect may comprise the method of the first aspect, optionally including any optional features thereof. The method of the fourth aspect may comprise use of the apparatus of the second aspect, optionally in any optional form thereof. The method of the fourth aspect may comprise use of the computer programme product of the third aspect, optionally in any optional form thereof.

The surgical navigation system used in the fourth aspect of the invention may comprise a detector, a display and a processor. The step of targeting the nerve in the head, neck or back in the method of the fourth aspect may comprise: detecting, using the detector of the surgical navigation system, a position of the cryogenic surgical intervention device; reconciling, using the computer processor, an MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient; determining and tracking, using the computer processor, a position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; and displaying, using a display of the surgical navigation system, the position of the surgical intervention device relative to the nerve in the head, neck or back. Prior to the step of cryoneurolysing the nerve in the method of the fourth aspect, the method may comprise directing the cryogenic surgical intervention device to the nerve based on the displayed position of the surgical intervention device relative to the nerve.

The surgical navigation system used in the fourth aspect of the invention may comprise a reference marker. The step of targeting the nerve in the head, neck or back may comprise: detecting, using the detector of the surgical navigation system, the reference marker of the surgical navigation system. The step of reconciling an MRI image of the anatomy of the patient with the anatomy of the patient may comprise reconciling the detected position of the reference marker with the MRI image.

The method of the fourth aspect may comprise targeting a deep sensory nerve segment of the nerve; and cryoneurolysing the deep sensory nerve segment of the nerve In a fifth aspect, there is provided a method of treating a condition of a nerve in a head, neck or back of a patient, the method comprising cryoneurolysing a deep sensory nerve segment of the nerve in the head, neck or back of the patient with a cryogenic surgical intervention device.

-20 -The method of the fifth aspect may comprise the method of the first aspect, optionally including any optional features thereof. The method of the fifth aspect may comprise use of the apparatus of the second aspect, optionally in any optional form thereof. The method of the fifth aspect may comprise use of the computer programme product of the third aspect, optionally inclusive of any optional feature thereof.

The deep sensory nerve segment targeted in the method of the fifth aspect or in the optional form of the fourth aspect may be a nerve segment that cannot be identified with ultrasound imaging, CT imaging, fluoroscopy or visually.

The deep sensory nerve segment may be a periforaminal nerve segment.

The periforaminal nerve segment may be a nerve segment that is situated within 7 cm of a base of the skull of the patient and/or within 7 cm of a vertebral foramen/foramina. The periforaminal nerve segment may be a neural structure exiting any opening in a bone or between bones (e.g. foramina, fissures and canals carrying neural structures) The condition treated by the method of the fourth or fifth aspects, the condition which the apparatus of the second aspect is suitable for treating, and/or a condition which the method of the first aspect and/or or the computer programme product of the third aspect may permit treatment of may be a pain condition. The pain condition may be at least one of a headache, trigeminal pain, a neuralgia, facial pain, neck pain, thoracic pain, lumbar pain, sacral pain and coccygeal pain. The pain condition may be trigeminal pain. Trigeminal pain may be any disease or disorder, systemic or local, causing pain in the trigeminal region, including traumas, being accidental or iatrogenic.

As above, the pain condition may be a neuralgia, and may be any of: trigeminal neuralgia (either or both of classical trigeminal neuralgia and symptomatic trigeminal neuralgia), glossopharyngeal neuralgia (either or both of classical and symptomatic glossopharyngeal neuralgia), nervus intermediate neuralgia, supraorbital neuralgia, other branch neuralgia, occipital neuralgia, post herpetic neuralgia, and a neuralgia attributed to systemic disorders such as multiple sclerosis.

As above, the pain condition may be facial pain. The facial pain may be any of: facial pain resulting from anaesthesia dolorosa, central post-stroke pain, facial pain attributed to multiple sclerosis, persistent idiopathic facial pain, burning mouth syndrome, temporomandibular pain, and facial pain attributed to herpes zoster. -21 -

As above, the pain condition may be a headache. The headache may be any type of a primary headache or any type of secondary headache.

For example, the primary headache may be any one of a cluster headache, migraine, tension-type headache, hypnic headache, short lasting unilateral neuralgiform headache with conjunctival injection and tearing /cranial autonomic features (SUNCT/SUNA), hemicrania continua, paroxysmal hemicrania, chronic daily pain, sphenopalatine ganglion neuralgia (also termed lower-half headache, lower facial neuralgia syndrome, Sluder's neuralgia, and Sluder's syndrome), carotidynia, Vidian neuralgia, causalgia, atypical odontalgia, or cluster tic syndrome.

Paroxysmal hemicrania is a primary headache disorder involving frequent attacks of unilateral, pen-orbital and temporal pain typically lasting less than 30 minutes. The pain can be associated with conjunctival injection, lacrimation, nasal congestion, rhinorrhea, ptosis and eyelid edema.

SUNCT/SUNA is a primary headache disorder characterized by multiple attacks of unilateral, pen-orbital and temporal pain typically lasting less than 2 minutes. The pain is associated with conjunctival injection, lacrimation, nasal congestion, rhinorrhea, and eyelid edema. This headache may be associated with trigeminal neuralgia.

Hemicrania continua is a primary headache disorder characterized by a strictly unilateral headache responsive to Indomethacin. The pain is associated with conjunctival injection, lacrimation, nasal congestion, rhinorrhea, ptosis, and eyelid edema.

The secondary headache may be any of a headache attributed to head and/or neck trauma for examples including chronic post-traumatic headache; a headache attributed to cranial or cervical vascular disorder; a headache attributed to non-vascular intracranial disorder including neoplasm and high and/or low cerebrospinal fluid pressure; a headache attributed to a substance or its withdrawal including medication overuse headache; a headache attributed to infection including chronic post-infection headache; a headache attributed to disorder of homoeostasis; a headache attributed to disorder of cranium, neck, eyes, ears, nose, sinuses, teeth, mouth or other facial or cranial structures, for example including headaches attributed to disorders of the neck (e.g. cervicogenic headache), rhinosinusitis, disorders of the teeth, jaws, or temporomandibular joint.

As above, the pain condition may be neck, thoracic, lumbal, sacral and/or coccygeal pain, which may be any of: radiculopathy, spondylotic myelopathy, -22 -myalgias, pain from acute traumatic injury, chronification of pain from acute traumatic injury, spondylosis, discogenic pain, pain associated with disc herniations, pain associated with whiplash injury, facet osteoarthritis, facet joint pain, myofascial pain syndrome, ossification of the posterior longitudinal ligament, pain attributed to oncologic disease, chiari malformations, polymyalgia rheumatic, fibromyalgia, non-specific back pain, spinal cord compression, cauda equina compression, vertebral osteomyelitis, vertebral compression fracture, spinal stenosis, ankylosin spondylitis, osteoarthritis, scoliosis and hyperkyphosis, piriformis syndrome and sacroiliac joint dysfunction.

The pain condition may be Complex Regional Pain Syndrome (CRPS).

The pain conditions may be occipital neuralgia or a headache affecting at least one of: a greater occipital nerve, a lesser occipital nerve, a third occipital nerve, a Cl vertebrae spinal nerve, a 02 spinal nerve, a 03 spinal nerve, any spinal nerve between and including the Cl spinal nerve to coccygeal nerve, a posterior (dorsal) ramus of a spinal nerve, a medial branch of a posterior (dorsal) ramus, a lateral branch of a posterior (dorsal) ramus, a meningeal branch (e.g. recurrent meningeal or sinuvertebral nerves) or a cervical plexus (superficial, intermediate and/or deep).

As already set out above, the nerve referred to in any of the above aspects of the invention may be a predominantly autonomic nerve. The predominantly autonomic nerve may be a pterygopalatine nerve.

Alternatively, the nerve referred to in any of the above aspects of the invention may be a predominantly sensory nerve. The predominantly sensory nerve may be a trigeminal nerve, and in particular may be a trigeminal nerve where the condition is trigeminal pain or trigeminal neuralgia.

The method of the fourth or fifth aspects may comprise cryoneurolysing the mandibular nerve (V3) of the trigeminal nerve.

The method of the fourth of fifth aspects may comprise cryoneurolysing the auriculotemporal nerve and/or the meningeal branch of the mandibular nerve (V3).

The meningeal branch may be termed the meningeal recurrent branch of the mandibular nerve (V3) and/or the nervus spinosus The method of the fourth or fifth aspects may comprise cryoneurolysing the mandibular nerve (V3) at the interpterygoid space.

-23 -The method of the fourth or fifth aspects may comprise cryoneurolysing the buccal nerve, the lingual nerve or the inferior alveolar nerve of the mandibular nerve (V3).

The method of the fourth or fifth aspects may comprise cryoneurolysing the maxillary nerve (V2) of the trigeminal nerve.

The method of the fourth or fifth aspects may comprise cryoneurolysing the maxillary nerve (V2) of the trigeminal nerve at the foramen rotundum.

The method of the fourth or fifth aspects may comprise cryoneurolysing the ophthalmic nerve (V1) of the trigeminal nerve.

The method of the fourth or fifth aspects may comprise cryoneurolysing the frontal nerve of the ophthalmic nerve (V1).

The method of the fourth or fifth aspects may comprise cryoneurolysing the supratrochlear nerve or the supraorbital nerve.

The nerve of any of the above aspects may be one of: a greater occipital nerve, a lesser occipital nerve, a third occipital nerve, a Cl vertebrae spinal nerve, a 02 spinal nerve, a 03 spinal nerve, any spinal nerve between and including the Cl spinal nerve to the coccygeal nerve, a posterior (dorsal) ramus of a spinal nerve, a medial branch of a posterior (dorsal) ramus, a lateral branch of a posterior (dorsal) ramus, a meningeal branch (e.g. recurrent meningeal or sinuvertebral nerves) or cervical plexus (superficial, intermediate and/or deep). These nerves may be targeted/cryoneurolysed where the condition to be treated, or subsequently to be treated, is occipital neuralgia or a headache affecting at least one of: a greater occipital nerve, a lesser occipital nerve, a third occipital nerve, a Cl vertebrae spinal nerve, a 02 spinal nerve, a 03 spinal nerve, any spinal nerve between and including the Cl spinal nerve to the coccygeal nerve, a posterior (dorsal) ramus of a spinal nerve, a medial branch of a posterior (dorsal) ramus, a lateral branch of a posterior (dorsal) ramus, a meningeal branch (e.g. recurrent meningeal or sinuvertebral nerves) or cervical plexus (superficial, intermediate and/or deep).

In a sixth aspect, there is provided a computer programme product comprising instructions that, when executed on a surgical navigation system, configures the surgical navigation system to carry out the method of the fourth and/or fifth aspects.

Certain embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which: -24 -Figure 1 shows a surgical navigation system for targeting a nerve in a head, neck or back of a patient in combination with a cryogenic surgical intervention device; Figure 2 depicts the anatomical features of a nerve; Figure 3 is a schematic representation of the anatomy of the trigeminal nerve; Figure 4 is a horizontal cross-sectional MRI image of a head of a patient; and Figure 5 is a coronal cross-sectional MRI image of the of a head of a patient Figure 1 shows a surgical navigation system 1 for guided cryogenic surgical intervention on a patient 2. The surgical navigation system 1 permits targeting and a subsequent cryoneurolysis of a nerve in the head, neck or back of a patient 2 with the cryogenic surgical intervention device 11 as will be described below.

The surgical navigation system 1 comprises a display 3, a computer processor (not shown) and a memory (also not shown) that are both embedded in the same unit comprising the display 3. The surgical navigation system 1 further comprises a combined emitter and detector 5, a reference marker 7 comprising a first surgical navigation array 8 and a second surgical navigation array 9.

The first surgical navigation array 8, which is fixed to the head of the patient 2 such that it is fixed relative to the anatomy of the patient 2, comprises three optically reflective spheres 8a-8c. The optically reflective spheres 8a-8c are adapted to reflect infrared light as will be described in greater detail below.

The second surgical navigation array 9 is fixedly mounted to the cryogenic surgical intervention device 11 in a known position/orientation to a working end of the surgical intervention device 11. The surgical navigation array 9 is broadly comparable in structure to the first surgical navigational array 8. That is, the second surgical navigation array 9 comprises three optically reflective spheres 9a-9c fixedly positioned relative to one another in an irregular manner. The optically reflective spheres 9a-9c are adapted to reflect infrared light as will be described in greater detail below.

The combined emitter and detector 5 is in communication with the processor and is configured to emit light at infrared wavelengths under the control of the processor. The combined emitter and detector 5 is also configured to detect for any of the emitted infrared light that has been reflected back to it, e.g., by the optically -25 -reflective spheres 8a-8c or the optically reflective spheres 9a-9c. If any reflected infrared light is detected at the emitter and detector 5 then the emitter and detector 5 is configured to communicate to the processor information about the reflected light which permits for an origin of the reflected infrared light to be determined.

The processor, in addition to controlling the combined emitter and detector 5, is (as above) arranged to receive information about the reflected infrared light received at the combined emitter and detector 5 and to process this information in order to determine the origin/origins of any reflected infrared light detected. More specifically, as discussed further below, the processor is arranged to determine the position of the patient 2 (i.e. the position of the anatomy of the patient) by determining the position of the reference marker 7 fixedly attached to the patient and to equally determine the position of the cryogenic surgical intervention device 11 by determining the position of the surgical navigation array 9 fixedly attached thereto. This determination is enabled by the detection of infrared light, which was initially emitted from the combined emitter and detector 5, that has been reflected from the optically reflective spheres 8a-8c and the optically reflective spheres 9a-9c forming part of the reference marker 7 and the second surgical navigation array 9, respectively.

The processor is further configured to reconcile an MRI image of the patient 2 showing a nerve in the head, neck or back of the patient with the patient's 2 actual anatomy that has been determined through detection of the position of the reference marker 7. The MRI image, which is stored in the memory, is communicated to the processor, and the processor then reconciles the MRI image with the anatomy of the patient by mapping/superimposing the MR1 image of the patient 2 over the determined anatomy of the patient 2.

The display 3, which is in communication with the processor, is configured to display both the MRI image of the patient 2 as reconciled with the position of the patient's anatomy and the determined position of the of the cryogenic surgical intervention device 11. In that way, an interventionist is able to view the relative position between the surgical intervention device 11 and the position of anatomical features of the patient 2 as depicted in the MRI image, most notably the position of the nerve in the head, neck or back of the patient 2 that is to be targeted for subsequent cryoneurolysis.

The processor is able to track the position of the cryogenic surgical intervention device 11 during its movement by, e.g., an interventionist relative to the -26 -anatomy of the patient 2 (and indeed is similarly able to track any inadvertent motion of the patient 2/ reference marker 7 though, as will be appreciated by the skilled person, movement of the patient 2/reference marker 7 would largely be avoided during any intervention procedure). This is achieved through continued emission/ detection of reflected infrared right using the combined detector and emitter 5 and continued processing of the information associated with the detected, reflected infrared light. Any movement of the optically reflective spheres 8a-8c (resulting from patient 2 movement) and/or the optically reflective spheres 9a-9c (resulting from movement of the cryogenic surgical intervention device 11) can then be determined and tracked, and the processor can communicate these changed positions to the display 3 to thereby permit an interventionist to visualise how the relative position between the surgical intervention device 11 and the anatomy of the patient 2, and more specifically the nerve in the head, neck or back of the patient 2, has changed.

In use, and as noted above, the combination of the surgical navigation system 1 and the cryogenic surgical intervention device 11 allows an interventionist to target and cryoneurolyse a nerve in the head, neck or back of the patient 2 in order to treat an underlying condition. For example, the surgical navigation system 1 and the cryogenic surgical intervention device 11 can be used to target and cryoneurolyse a trigeminal nerve of the patient 2 in order to treat trigeminal neuralgia. Alternatively, the surgical navigation system 1 and the cryogenic surgical intervention device 11 can be used to target and cryoneurolyse an occipital nerve of the patient 2 in order to treat occipital neuralgia. These nerves and conditions are merely exemplary, and very many other nerves and/or conditions are targetable and/or treatable using the combination of the surgical navigation system 1 and the cryogenic surgical intervention device 11.

In the example of targeting and cryoneurolysing a trigeminal nerve, an MRI image showing the trigeminal nerve of the patient 2 may be taken and stored in the memory of the surgical navigation system 1. The patient 2 can then be prepared for the cryogenic surgical intervention procedure in a conventional manner as shown in Figure 1. This includes fixing the reference marker 7 to the patient 2. Once the patient 2 setup is completed, the processor controls the combined emitter and detector 5 to carry out emission of infrared light and detection of the emitted infrared light that has been reflected back to the combined emitter and detector 5. In particular, infrared light that has been reflected back from the -27 -optically reflective spheres 8a-8c forming part of the reference marker 7 and the optically reflected spheres 9a-9c that are fixedly mounted to the cryogenic surgical intervention device 11 is detected by the combined emitter and detector 5 and information relating to this reflected infrared light is sent back to the processor.

With the information received at the processor, the processor determines the spatial position of the optically reflective spheres 8a-8c and the optically reflective spheres 9a-9c, and thereby determines the spatial position of the patient 2 and the cryogenic surgical intervention device 11, and also the relative position between the patient 2 and the cryogenic surgical intervention device 11. The processor then reconciles the determined position of the patient 2 with the MRI image (communicated to the processor from the memory) showing the trigeminal nerve of the patient 2. This is then communicated to the display 3 along with the determined position of the cryogenic surgical intervention device 11, which are then both displayed such that an interventionist is able to visualise the position of the cryogenic surgical intervention device 11 (and in particular a working end of the surgical intervention device 11) relative to the trigeminal nerve. This enables an interventionist to direct the cryogenic intervention device 11 to the trigeminal nerve such that said nerve can be cryoneurolysed to thereby treat trigeminal neuralgia. As the interventionist moves the cryogenic surgical intervention device 11 into the patient 2 and toward the trigeminal nerve the processor tracks the movement of the intervention device 11 relative to the trigeminal nerve and communicates this movement to the display 3, optionally in real-time. This relative movement is therefore displayed to the interventionist to enable the interventionist to accurately target and later cryoneurolyse the trigeminal nerve, which allows for an effective treatment of trigeminal neuralgia.

Cryoneurolysis of the trigeminal nerve is an effective and advantageous treatment of trigeminal neuralgia (and indeed cryoneurolysis of nerves, generally, can be effective for treatment of various other conditions) because it offers a reversible block to the nerve and therefore provides freedom to the patient 2 from associated pain.

Cryoneurolysis involves freezing a target nerve 30 (see Figure 2), using the cryogenic surgical intervention device 11. This freezing results in a Wallerian degeneration of the nerve 30. Wallerian degeneration comprises destruction of the axons 31 of the nerve 30 and the encasing myelin sheath 32; however, the surrounding endoneurium tubes 33, perineurium 34 and epineurium 35 remain -28 -intact during Wallerian degeneration. Given that these structures remain intact after freezing, the axons 31 and myelin 32 are able to regenerate and thereby permit the nerve 30 to regain function.

Cryoneurolysis thus provides a reversible block to the functioning of the nerve 30 since the nerve 30 will eventually regenerate. The duration of the reversible block depends on the distance between the point of application of cryoneurolysis treatment and the nerve 30 endings. Nerves will regenerate at a speed of approximately 1-2 mm per day and even after regeneration may take far longer to regain full function. As such, conditions of nerves (e.g. trigeminal neuralgia of the trigeminal nerve) can be blocked, albeit reversibly using cryoneurolysis.

Figure 3 is a schematic representation of the anatomy of the trigeminal nerve 40, which as discussed above is a target nerve of particular relevance in context of the current invention due to the prevalence and severity of trigeminal neuralgia and other conditions afflicting the trigeminal nerve 40. The invention enables treatment of this conditions afflicting the trigeminal nerve 40 through cryoneurolysis of the trigeminal nerve 40.

As shown, the trigeminal nerve 40 extends from the trigeminal ganglion 41 and branches into the ophthalmic nerve 42, the maxillary nerve 48 and the mandibular nerve 49.

The ophthalmic nerve 42 itself later divides out into the nasocillary nerve 43, the lacrimal nerve 44 and the frontal nerve 45, which itself divides into the supratrochlear 46 and the suprafrontal nerve 47.

The mandibular nerve 49 has a meningeal branch 50 and a branch 51 associated with the medial pterygoid, tensor tympani, and tensor veli palatini. The mandibular nerve 49 also itself divides, in part into an anterior division 52, which has a branch 53 leading to the deep temporal nerves and which itself divides into the masseteric nerve 54, the lateral pterygoid nerve 55 and the buccal nerve 56. The other division of the mandibular nerve 49 is the posterior division 57, which divides into the lingual nerve 58, the inferior alveor 59 and the auriculotemporal nerve 60.

The supratrochlear nerve 46, the suprafrontal nerve 47, the maxillary nerve 48, the buccal nerve 56, the lingual nerve 58, the inferior alveor 59 and the auriculotemporal nerve 60 are each predominantly sensory nerves/nerve segments and are hence useful to target for cryoneurolysis in the context of the current -29 -invention since cryoneurolysis of these nerves/ nerve segments can provide a pain block, albeit reversible, to any conditions (e.g. trigeminal neuralgia) afflicting these nerves. Moreover, in the event of an inadvertent (i.e. unavoidable) denervation of motor or autonomic fibre in each of these predominantly sensory nerves/nerve segments, there would be no or negligible clinically significant adverse effects experienced given the low density and importance of autonomic nerve fibres/motor nerve fibres in these nerves/nerve segments.

As will be apparent from the above discussion of Wallerian degeneration in relation to Figure 2, it is of greatest benefit, with respect to the length of block provided to the nerve, to cryoneurolyse the nerve as proximally as possible. With reference to the trigeminal nerve 40 shown in Figure 3, the longest block would be provided when the nerve 40 is cryoneurolysed as close to the trigeminal ganglion 41 as possible. Of course, there is a trade off in that the most proximal portions of a nerve can be difficult to target given that access to the them with a cryogenic intervention device can be occluded by other parts of the patient's anatomy.

Moreover, the most proximal portions of nerves often comprise a mix of autonomic, sensory and motor nerve fibres, and it may be disadvantageous to destroy all of types of nerve fibres during cryoneurolysis given unwanted adverse effects to the patient may occur. Therefore, to reduce adverse effects to the patient, it can be beneficial to target/ destroy nerves/nerve segments comprising only or predominantly a single type of nerve fibre, in particular a predominantly sensory nerve/ nerve segment.

Accordingly, in the context of the invention, it can be beneficial to strike a balance between the length of block provided to the nerve and access to a suitable/appropriate portion of the nerve along with adverse effects to the patient when selecting the target site of the nerve to apply the cryoneurolytic treatment. In the context of the trigeminal nerve 40, suitable target sites that appropriately strike this balance include the supratrochlear nerve 46, the suprafrontal nerve 47, the maxillary nerve 48 when accessed via the foramen rotundum 61, the auriculotemporal nerve 60, or any one of the buccal nerve 56, the lingual nerve 58, and the inferior alveor 59 when accessed via the interpterygoid space 63. Each of these target sites are spaced far enough from the trigeminal ganglion 41 such that they have mostly divided from autonomic and motor nerve fibres and thereby are predominantly sensory nerves/nerve segments of the trigeminal nerve 40, but are equally sufficiently proximal to the trigeminal ganglion -30 - 41 such that cryoneurolysis at these sites provides a reasonable length of block to the relevant nerve/ nerve segment. These sites are thus each deep sensory nerves/ deep sensory nerve segments. Moreover, these target sites can be accessed with a cryogenic surgical intervention device without significant occlusion from and detriment to other anatomical structures.

However, to access these target sites, guidance based on MRI imaging is required since these target sites cannot otherwise be accurately targeted accessed by an interventionist with the cryogenic surgical intervention device given they lie too deep to be targeted using a visual inspection by an interventionist, too far from a bony landmark of the patient to be targeted using computer tomography or fluoroscopic techniques, and also cannot be readily accessed using ultrasound based techniques. This is as demonstrated in Figures 4 and 5, which show MRI images 70, 80 of a head of patient. Regions 71, 81 demonstrate portions of the trigeminal nerve that are only identifiable using MRI guided cryosurgical interventions. The remaining regions 72-74 and 82-84 demonstrate portions of the trigeminal nerve which can be accessed with other modalities in addition to MRI guided surgical interventions. For example, regions 72, 73, 82, 83 can be accessed using fluoroscopic techniques imaging techniques given their proximity to bony landmarks, whilst regions 74, 84 can be accessed using ultrasound-based.

-31 -Clauses The following clauses set out aspects and/or features of the invention, which may or may not be presently claimed, but which may form the basis for future amendments and/or divisional applications, and which provide priority basis for any later priority claiming application(s).

1 A method of targeting a nerve in a head, neck or back of a patient using a surgical navigation system, the method comprising: providing a cryogenic surgical intervention device, wherein the cryogenic surgical intervention device is adapted to cryoneurolyse the nerve in the head, neck or back of the patient; detecting, using a detector of the surgical navigation system, a position of the cryogenic surgical intervention device; reconciling, using a computer processor of the surgical navigation system, an MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient; determining and tracking, using the computer processor, a position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; and displaying, using a display of the surgical navigation system, the position of the surgical intervention device relative to the nerve in the head, neck or back; wherein the displayed position of the surgical intervention device relative to the nerve in the head, neck or back is configured to permit an interventionist to direct the cryogenic intervention device to the nerve in the head, neck or back such that said nerve can be cryoneurolysed.

2. A method as in clause 1, comprising detecting, using the detector of the surgical navigation system, a reference marker of the surgical navigation system that is fixed relative to the anatomy of the patient, and wherein the step of reconciling, using the computer processor of the surgical navigation system, the MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient comprises -32 -reconciling, using a computer processor of the surgical navigation system, the detected position of the reference marker with the MRI image.

3. A method as in clause 1 or 2, wherein targeting the nerve comprises targeting a deep sensory nerve segment of the nerve, wherein the MRI image shows the deep sensory nerve segment of the nerve, wherein the position of the surgical intervention device is determined and tracked relative to the deep sensory nerve segment, wherein the position of the surgical intervention device is displayed relative to the deep sensory nerve segment, and wherein the displayed position is configured to permit an interventionist to direct the cryogenic intervention device to the deep sensory nerve segment.

4. A method as in clause 3, wherein the deep sensory nerve segment is a nerve segment that cannot be identified with ultrasound imaging, CT imaging, fluoroscopy or visually.

5. A method as in clause 3 or 4, wherein the deep sensory nerve segment is a periforaminal nerve segment.

6. A method as in clause 5, wherein the periforaminal nerve segment is a nerve segment that is situated within 7 cm of a base of the skull of the patient and/or within 7 cm of a vertebral foramen/foramina.

7. A method as in any preceding clause, wherein the nerve is a cranial nerve.

8. A method as in clause 7, wherein the cranial nerve is one of: a glossopharyngeal nerve, a petrosal nerve or a vagus nerve.

9. A method as in clause 7, wherein the cranial nerve is a trigeminal nerve.

10. A method as in clause 9, wherein the method comprises targeting the mandibular nerve (V3) of the trigeminal nerve.

11. A method as in clause 10, comprising targeting the auriculotemporal nerve and/or the meningeal branch of the mandibular nerve (V3).

-33 - 12. A method a in clause 10, comprising targeting the mandibular nerve (V3) at the interpterygoid space.

13. A method as in clause 10 or 12, comprising targeting the buccal nerve, the lingual nerve and/or the inferior alveolar nerve of the mandibular nerve (V3).

14. A method as in clause 9, wherein the method comprises targeting the maxillary nerve (V2) of the trigeminal nerve.

15. A method as in clause 14, wherein the method comprises targeting the maxillary nerve (V2) of the trigeminal nerve at the foramen rotundum.

16. A method as in clause 9, wherein the method comprises targeting the ophthalmic nerve (V1) of the trigeminal nerve.

17. A method as in clause 16, wherein the method comprises targeting the frontal nerve.

18. A method as in clause 17, wherein the method comprises targeting the supratrochlear nerve or the supraorbital nerve of the frontal nerve.

19. A method as in any of clauses 1 to 6, wherein the nerve in the head, neck or back of the patient is a spinal nerve or spinal nerve branch.

20. A method as in clause 19, wherein the spinal nerve or spinal nerve branch is one of: a greater occipital nerve, a lesser occipital nerve, a third occipital nerve, a Cl vertebrae spinal nerve, a C2 spinal nerve, a 03 spinal nerve, any spinal nerve between and including the C1 spinal nerve to the coccygeal nerve, a posterior (dorsal) ramus of a spinal nerve, a medial branch of a posterior (dorsal) ramus, a lateral branch of a posterior (dorsal) ramus, a meningeal branch (e.g. recurrent meningeal or sinuvertebral nerves), a cervical plexus (superficial, intermediate and/or deep).

21. A method as in any preceding clause, wherein the nerve is a predominantly sensory nerve -34 - 22. A method as in any of clauses 1 to 7 or 19, wherein the nerve is a predominantly autonomic nerve.

23. A method as in clause 22, wherein the nerve is a pterygopalafine nerve 5 24. An apparatus for treatment of a condition of a nerve in a head, neck or back of a patient, the apparatus comprising: a cryogenic surgical intervention device, wherein the cryogenic surgical intervention device is adapted to cryoneurolyse the nerve in the head, neck or back; and a surgical navigation system comprising: a detector configured to detect a position of the cryogenic surgical intervention device; a computer processor configured to reconcile an MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient; wherein the computer processor is further configured to determine and track a position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; and a display configured to display the position of the surgical intervention device relative to the nerve in the head, neck or back as depicted in the MRI image; and wherein, based on a displayed position of the surgical intervention device relative to the nerve in the head, neck or back, the surgical navigation system permits an interventionist to direct the cryogenic surgical intervention device to the nerve in the head, neck or back to thereby cryoneurolyse said nerve.

25. An apparatus as in clause 24, wherein the surgical navigation system comprises a reference marker adapted to be fixed relative to the anatomy of the patient, wherein the detector is configured to detect the reference marker, and wherein the computer processor is configured to reconcile the detected position of the reference marker with the MRI image to thereby reconcile the MRI image with the anatomy of the patient.

-35 - 26. An apparatus as in clause 24 or 25, wherein the cryogenic surgical intervention device comprises a cryoneedle or a cryoprobe that is adapted to cryoneurolyse the nerve in the head, neck or back.

27. An apparatus as in any of clauses 24, 25 or 26, wherein the nerve is a predominantly sensory nerve.

28. An apparatus as in any of clauses 24, 25, 26 or 27, wherein the nerve is a trigeminal nerve.

29. An apparatus as in clause 28, where the condition is trigeminal neuralgia.

30. An apparatus as in any of clauses 24, 25, 26 or 27, wherein the nerve is one of: a greater occipital nerve, a lesser occipital nerve, a third occipital nerve, a Cl vertebrae spinal nerve, a C2 spinal nerve, a C3 spinal nerve, any spinal nerve between and including the Cl spinal nerve to the coccygeal nerve, a posterior (dorsal) ramus of a spinal nerve, a medial branch of a posterior (dorsal) ramus, a lateral branch of a posterior (dorsal) ramus, a meningeal branch (e.g. recurrent meningeal or sinuvertebral nerves) or cervical plexus (superficial, intermediate and/or deep).

31. An apparatus as in any of clauses 24, 25 or 26, wherein the nerve is a predominantly autonomic nerve.

32. An apparatus as in clause 31, wherein the nerve is a pterygopalatine nerve.

33. An apparatus as in any of clauses 24 to 32, wherein the cryogenic surgical intervention device is adapted to cryoneurolyse a deep sensory nerve segment of the nerve, wherein the MRI image shows the deep sensory nerve segment of the nerve, wherein the processor is configured to determine and track the position of the surgical intervention device relative to the deep sensory nerve segment, wherein the display is configured to display the position of the surgical intervention device relative to the deep sensory nerve segment, and wherein the displayed position permits an interventionist to direct the cryogenic surgical intervention device to the deep sensory nerve segment.

-36 - 34. An apparatus as in any of clauses 24 to 33, wherein the condition is a pain condition.

35. An apparatus as in clause 34, wherein the pain condition is at least one of a headache, trigeminal pain, a neuralgia, facial pain, neck pain, thoracic pain, lumbar pain, sacral pain and coccygeal pain.

36. A computer programme product comprising instructions that when executed on a computer processor of a surgical navigation system will configure the surgical navigation system to: detect, using the detector, a position of a cryogenic surgical intervention device, wherein the cryogenic surgical intervention device is adapted to cryoneurolyse a nerve in the head, neck or back of a patient; reconcile an MRI image of the anatomy of a patient showing the nerve in the head, neck or back with the anatomy of the patient; determine and track a position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; display, using a display of the surgical navigation system, the position of the surgical intervention device relative to the nerve in the head, neck or back; and guide, using the display, an interventionist in directing the cryogenic intervention device to nerve in the head, neck or back such that said nerve can be cryoneurolysed.

37. A computer programme product in accordance with clause 36, comprising instructions that when executed on the computer process of the surgical navigation system will configure the surgical navigation system to: detect, using the detector of the surgical navigation system, a reference marker of the surgical navigation system that is fixed relative to the anatomy of the patient; and reconcile the detected position of the reference marker with the MRI image of the anatomy of the patient to thereby reconcile the MRI image of the anatomy of the patient with the anatomy of the patient.

-37 - 38. A method of treating a condition of a nerve in a head, neck or back of a patient, the method comprising targeting the nerve in the head, neck or back of a patient with an MRI image based surgical navigation system; and cryoneurolysing the nerve in the head, neck or back of the patient with a cryogenic surgical intervention device.

39. A method of treating a condition as in clause 38, wherein the surgical navigation system comprises a detector, a display and a processor; wherein the step of targeting the nerve in the head, neck or back comprises: detecting, using the detector, a position of the cryogenic surgical intervention device; reconciling, using the computer processor, an MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient; determining and tracking, using the computer processor, a position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; and displaying, using the display of the surgical navigation system, the position of the surgical intervention device relative to the nerve in the head, neck or back; and prior to the step of cryoneurolysing the nerve, directing the cryogenic surgical intervention device to the nerve based on the displayed position of the surgical intervention device relative to the nerve.

40. A method of treating a condition as in clause 39, wherein the surgical navigation system comprises a reference marker; wherein the step of targeting the nerve in the head, neck or back comprises: detecting, using the detector of the surgical navigation system, the reference marker of the surgical navigation system; and wherein the step of reconciling an MRI image of the anatomy of the patient with the anatomy of the patient comprises reconciling the detected position of the reference marker with the MRI image.

-38 - 41. A method of treating a condition as in any of clauses 38, 39 01 40, comprising targeting a deep sensory nerve segment of the nerve; and cryoneurolysing the deep sensory nerve segment of the nerve 42. A method of treating a condition of a nerve in a head, neck or back of a patient, the method comprising cryoneurolysing a deep sensory nerve segment of the nerve in the head, neck or back of the patient with a cryogenic surgical intervention device.

43. A method of treating a condition as in clause 41 or 42, wherein the deep sensory nerve segment is a nerve segment that cannot be identified with ultrasound imaging, CT imaging, fluoroscopy or visually.

44. A method of treating a condition as in clause 41,42 or 43, wherein the deep sensory nerve segment is a periforaminal nerve segment.

45. A method of treating a condition as in clause 44, wherein the periforaminal nerve segment is a nerve segment that is situated within 7 cm of a base of the skull of the patient and/or within 7 cm of a vertebral foramen/foramina.

46. A method of treating a condition as in any of clauses 38 to 45, wherein the condition is a pain condition.

47. A method as in clause 46, wherein the pain condition is at least one of a headache, trigeminal pain, a neuralgia, facial pain, neck pain, thoracic pain, lumbar pain, sacral pain and coccygeal pain.

48. A method of treating a condition as in any of clauses 38 to 47, wherein the nerve is a predominantly autonomic nerve.

49. A method of treating a condition as in clause 48, wherein the predominantly autonomic nerve is a pterygopalatine nerve.

50. A method of treating a condition as in any of clauses 38 to 47, wherein the nerve is a predominantly sensory nerve -39 - 51. A method of treating a condition as in any of clauses 38 to 47 01 50, wherein the nerve is a trigeminal nerve.

52. A method as in clause 51, wherein the condition is trigeminal pain or trigeminal neuralgia.

53. A method as in clause 51 or 52, wherein the method comprises cryoneurolysing the mandibular nerve (V3) of the trigeminal nerve.

54. A method as in clause 53, comprising cryoneurolysing the auriculotemporal nerve and/or the meningeal branch of the mandibular nerve (V3).

55. A method as in clause 53, comprising cryoneurolysing the mandibular nerve (V3) at the interpterygoid space.

56. A method as in clause 53, comprising cryoneurolysing the buccal nerve, the lingual nerve or the inferior alveolar nerve of the mandibular nerve (V3).

57. A method as in clause 51 or 52, wherein the method comprises cryoneurolysing the maxillary nerve (V2) of the trigeminal nerve.

58. A method as in clause 57, wherein the method comprises cryoneurolysing the maxillary nerve (V2) of the trigeminal nerve at the foramen rotundum.

59. A method as in clause 51 or 52, wherein the method comprises cryoneurolysing the ophthalmic nerve (V1) of the trigeminal nerve.

60. A method as in clause 59, wherein the method comprises cryoneurolysing the frontal nerve of the ophthalmic nerve.

61. A method as in clause 60, wherein the method comprises cryoneurolysing the supratrochlear nerve or the supraorbital nerve.

62. A method as in any of clauses 38 to 47 01 50, wherein the nerve is one of: a greater occipital nerve, a lesser occipital nerve, a third occipital nerve, a Cl vertebrae spinal nerve, a C2 spinal nerve, a 03 spinal nerve, any spinal nerve between and including the C1 spinal nerve to the coccygeal nerve, a posterior (dorsal) ramus of a spinal nerve, a medial branch of a posterior -40 - (dorsal) ramus, a lateral branch of a posterior (dorsal) ramus, a meningeal branch (e.g. recurrent meningeal or sinuvertebral nerves) or a cervical plexus (superficial, intermediate and/or deep).

63. A method as in clause 62, wherein the condition is occipital neuralgia or a headache affecting at least one of: a greater occipital nerve, a lesser occipital nerve, a third occipital nerve, a Cl vertebrae spinal nerve, a C2 spinal nerve, a C3 spinal nerve, any spinal nerve between and including the Cl spinal nerve to the coccygeal nerve, a posterior (dorsal) ramus of a spinal nerve, a medial branch of a posterior (dorsal) ramus, a lateral branch of a posterior (dorsal) ramus, a meningeal branch (e.g. recurrent meningeal or sinuvertebral nerves), a cervical plexus (superficial, intermediate and/or deep).

Claims

-41 -Claims 1 A method of targeting a nerve in a head, neck or back of a patient using a surgical navigation system, the method comprising: providing a cryogenic surgical intervention device, wherein the cryogenic surgical intervention device is adapted to cryoneurolyse the nerve in the head, neck or back of the patient; detecting, using a detector of the surgical navigation system, a position of the cryogenic surgical intervention device; reconciling, using a computer processor of the surgical navigation system, an MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient; determining and tracking, using the computer processor, a position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; and displaying, using a display of the surgical navigation system, the position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; wherein the displayed position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back is configured to permit an interventionist to direct the cryogenic intervention device to the nerve in the head, neck or back such that said nerve can be cryoneurolysed.
2. A method as claimed in claim 1, comprising detecting, using the detector of the surgical navigation system, a reference marker of the surgical navigation system that is fixed relative to the anatomy of the patient, and wherein the step of reconciling, using the computer processor of the surgical navigation system, the MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient comprises reconciling, using the computer processor of the surgical navigation system, the detected position of the reference marker with the MRI image.
3. A method as claimed in claim 1 or 2, wherein targeting the nerve comprises targeting a deep sensory nerve segment of the nerve, wherein the MRI image shows the deep sensory nerve segment of the nerve, wherein the -42 -position of the surgical intervention device is determined and tracked relative to the deep sensory nerve segment, wherein the position of the surgical intervention device is displayed relative to the deep sensory nerve segment, and wherein the displayed position is configured to permit an interventionist to direct the cryogenic intervention device to the deep sensory nerve segment.
4. A method as claimed in claim 3, wherein the deep sensory nerve segment is a nerve segment that cannot be identified with ultrasound imaging, CT imaging, fluoroscopy or visually.
5. A method as claimed in claim 3 or 4, wherein the deep sensory nerve segment is a periforaminal nerve segment.
6. A method as claimed in claim 5, wherein the periforaminal nerve segment is a nerve segment that is situated within 7 cm of a base of the skull of the patient and/or within 7 cm of a vertebral foramen/foramina.
7. A method as claimed in any preceding claim, wherein the nerve is a cranial nerve.
8. A method as claimed in claim 7, wherein the cranial nerve is one of a glossopharyngeal nerve, a petrosal nerve or a vagus nerve.
9. A method as claimed in claim 7, wherein the cranial nerve is a trigeminal nerve
10. A method as claimed in claim 9, wherein the method comprises targeting the mandibular nerve (V3) of the trigeminal nerve. 30
11. A method as claimed in claim 10, comprising targeting the auriculotemporal nerve and/or the meningeal branch of the mandibular nerve (V3).
12. A method as claimed in claim 10, comprising targeting the mandibular nerve (V3) at the interpterygoid space.-43 -
13. A method as claimed in claim 10 or 12, comprising targeting the buccal nerve, the lingual nerve and/or the inferior alveolar nerve of the mandibular nerve (V3).
14. A method as claimed in claim 9, wherein the method comprises targeting the maxillary nerve (V2) of the trigeminal nerve.
15. A method as claimed in 14, wherein the method comprises targeting the maxillary nerve (V2) of the trigeminal nerve at the foramen rotundum.
16. A method as claimed in claim 9, wherein the method comprises targeting the ophthalmic nerve (V1) of the trigeminal nerve.
17. A method as claimed in claim 16, wherein the method comprises targeting the frontal nerve.
18. A method as claimed in claim 17, wherein the method comprises targeting the supratrochlear nerve or the supraorbital nerve of the frontal nerve.
19. A method as claimed in any of claims 1 to 6, wherein the nerve in the head, neck or back of the patient is a spinal nerve or a spinal nerve branch.
20. A method as claimed in claim 19, wherein the spinal nerve or spinal nerve branch is one of: a greater occipital nerve, a lesser occipital nerve, a third occipital nerve, a Cl vertebrae spinal nerve, a C2 spinal nerve, a C3 spinal nerve, any spinal nerve between and including the Cl spinal nerve to the coccygeal nerve, a posterior (dorsal) ramus of a spinal nerve, a medial branch of a posterior (dorsal) ramus, a lateral branch of a posterior (dorsal) ramus, a meningeal branch (e.g. recurrent meningeal or sinuvertebral nerves) or a cervical plexus (superficial, intermediate and/or deep).
21. A method as claimed in any preceding claim, wherein the nerve is a predominantly sensory nerve.
22. A method as claimed in any of claims 1 to 7 or 19, wherein the nerve is a predominantly autonomic nerve.-44 -
23. A method as claimed in claim 22, wherein the nerve is a pterygopalafine nerve
24. An apparatus for treatment of a condition of a nerve in a head, neck or back of a patient, the apparatus comprising: a cryogenic surgical intervention device, wherein the cryogenic surgical intervention device is adapted to cryoneurolyse the nerve in the head, neck or back; and a surgical navigation system comprising: a detector configured to detect a position of the cryogenic surgical intervention device; a computer processor configured to reconcile an MRI image of the anatomy of the patient showing the nerve in the head, neck or back with the anatomy of the patient; wherein the computer processor is further configured to determine and track a position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; and a display configured to display the position of the surgical intervention device relative to the nerve in the head, neck or back as depicted in the MRI image; and wherein, based on a displayed position of the surgical intervention device relative to the nerve in the head, neck or back, the surgical navigation system permits an interventionist to direct the cryogenic surgical intervention device to the nerve in the head, neck or back to thereby cryoneurolyse said nerve.
25. An apparatus as claimed in claim 24, wherein the surgical navigation system comprises a reference marker adapted to be fixed relative to the anatomy of the patient, wherein the detector is configured to detect the reference marker, and wherein the computer processor is configured to reconcile the detected position of the reference marker with the MRI image to thereby reconcile the MRI image with the anatomy of the patient.-45 -
26. An apparatus as claimed in claim 24 or 25, wherein the cryogenic surgical intervention device comprises a cryoneedle or a cryoprobe that is adapted to cryoneurolyse the nerve in the head, neck or back.
27. An apparatus as claimed in any of claims 24, 25 or 26, wherein the nerve is a predominantly sensory nerve.
28. An apparatus as claimed in any of claims 24, 25, 26 or 27, wherein the nerve is a trigeminal nerve.
29. An apparatus as claimed in claim 28, where the condition is trigeminal neuralgia.
30. An apparatus as claimed in any of claims 24, 25, 26 or 27, wherein the nerve is one of: a greater occipital nerve, a lesser occipital nerve, a third occipital nerve, a Cl vertebrae spinal nerve, a C2 spinal nerve, a C3 spinal nerve, any spinal nerve between and including the Cl spinal nerve to the coccygeal nerve, a posterior (dorsal) ramus of a spinal nerve, a medial branch of a posterior (dorsal) ramus, a lateral branch of a posterior (dorsal) ramus, a meningeal branch (e.g. recurrent meningeal or sinuvertebral nerves) or a cervical plexus (superficial, intermediate and/or deep).
31. An apparatus as claimed in any of claims 24, 25 or 26, wherein the nerve is a predominantly autonomic nerve.
32. An apparatus as claimed in claim 31, wherein the nerve is a pterygopalatine nerve
33. An apparatus as claimed in any of claims 24 to 32, wherein the cryogenic surgical intervention device is adapted to cryoneurolyse a deep sensory nerve segment of the nerve, wherein the MRI image shows the deep sensory nerve segment of the nerve, wherein the processor is configured to determine and track the position of the surgical intervention device relative to the deep sensory nerve segment, wherein the display is configured to display the position of the surgical intervention device relative to the deep sensory nerve segment, and wherein the displayed position permits an -46 -interventionist to direct the cryogenic surgical intervention device to the deep sensory nerve segment.
34. An apparatus as claimed in any of claims 24 to 33, wherein the condition is a pain condition.
35. An apparatus as claimed in claim 34, wherein the pain condition is at least one of a headache, trigeminal pain, a neuralgia, facial pain, neck pain, thoracic pain, lumbar pain, sacral pain and coccygeal pain.
36. A computer programme product comprising instructions that when executed on a computer processor of a surgical navigation system will configure the surgical navigation system to: detect, using the detector, a position of a cryogenic surgical intervention device, wherein the cryogenic surgical intervention device is adapted to cryoneurolyse a nerve in the head, neck or back of a patient; reconcile an MRI image of the anatomy of a patient showing the nerve in the head, neck or back with the anatomy of the patient; determine and track a position of the cryogenic surgical intervention device relative to the nerve in the head, neck or back; display, using a display of the surgical navigation system, the position of the surgical intervention device relative to the nerve in the head, neck or back; and guide, using the display, an interventionist in directing the cryogenic intervention device to nerve in the head, neck or back such that said nerve can be cryoneurolysed.
37. A computer programme product in accordance with claim 36, comprising instructions that when executed on the computer process of the surgical navigation system will configure the surgical navigation system to: detect, using the detector of the surgical navigation system, a reference marker of the surgical navigation system that is fixed relative to the anatomy of the patient; and -47 -reconcile the detected position of the reference marker with the MRI image of the anatomy of the patient to thereby reconcile the MRI image of the anatomy of the patient with the anatomy of the patient.
38. A method of treating a condition of a nerve in a head, neck or back of a patient, the method comprising targeting the nerve in the head, neck or back of a patient with an MRI image based surgical navigation system; and cryoneurolysing the nerve in the head, neck or back of the patient with a cryogenic surgical intervention device.
39. A method of treating a condition of a nerve in a head, neck or back of a patient, the method comprising cryoneurolysing a deep sensory nerve segment of the nerve in the head, neck or back of the patient with a cryogenic surgical intervention device.