RU2729504C1 - Method of adjusting cochlear implant parameters in patients with otosclerosis - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: invention refers to medicine, particularly to otorhinolaryngology and audiology. Postaural incision is performed under general or local anesthesia; a mastoid process within the Chipault triangle is exposed. Periosteum is separated with soft tissues from the bones of the skull in the postaural region; a bed for the implant is formed. That is followed by an anthromastoidotomy and a posterior tympanotomy. Tympanic cavity is inspected, pathological tissue is removed in the region of the foot plate. Diamond drill is used to smooth pyramidal process from apex to base to expose a portion of stapedius muscle with length of up to 8 mm. Cochleostom is formed. Electrode grid of the cochlear implant is inserted through the cochleostoma into the scala tympani. Cochlear implant is stimulated on the electrodes. Stapedial reflex is visually recorded to reduce the stapedius muscle. Cochlear implant is fixed. Wound is sutured in layers.EFFECT: method enables more accurate tuning of the processor in implanted patients in otosclerosis due to good visualization of contractions of the stapedius muscle and improved results of speech-and-auditory rehabilitation in the patients with severe degree of hearing loss and deafness at the first connection.1 cl, 1 ex, 1 dwg

Description

Technology area

The invention relates to medicine, in particular to otorhinolaryngology and audiology, and can be used to determine the settings of the speech processor in implanted patients with otosclerosis with severe hearing loss and deafness at the first connection.

State of the art

Otosclerosis is a process of primary metabolic damage to the bone capsule of the ear labyrinth and the auditory ossicles, which is expressed as a special form of osteodystrophy with predominantly bilateral focal lesions of the enchondral layer of the capsule, which results in progressive hearing loss up to deafness.

This disease leads to a gradual increase in conductive, mixed or sensorineural hearing loss due to fixation of the stapes, footplate of the stapes and diffusion of proteolytic enzymes that cause damage to hair cells from the otosclerotic focus into the inner ear [1, 2].

If we consider the mixed and cochlear forms of otosclerosis (according to the classification of N.A. Preobrazhensky (1962)), all parts of the bone capsule of the labyrinth are susceptible to the pathological diffuse osteodystrophic process, including the niche of the vestibule window (ankylosis of the stirrup), therefore, in such patients, not only intratympanic sound conduction due to immobility of the stirrup, but, in some cases, intra-labyrinth conduction due to changes in the hydrodynamics of the labyrinth, as well as sound perception (due to disturbances in the electrolyte composition of inner ear fluids, the possible "toxic" effect of metabolites of vital activity of otosclerotic foci on the sensory epithelium labyrinth, which changes its functional state to parabiosis, and in some cases, possibly, morphological - up to its death) [3].

To confirm the diagnosis of otosclerosis, an important role is played by the data of tone-threshold audiometry, computed and magnetic resonance imaging of the temporal bones. The absence of an acoustic reflex of the stapes muscle is sometimes the earliest sign of otosclerosis. In case of otosclerosis with fixation of the stapes, both the ipsi and contralateral acoustic reflex of the stapes muscle disappears, which also makes it possible to suspect the presence of a mixed or cochlear form of otosclerosis in a patient - normal or somewhat reduced (from 4 to 10 dB in young patients, up to 15 dB in persons of the older age group) the values of the thresholds of auditory sensitivity to ultrasound (USV), determined by the method of B.M. Sagalovich (1963).

For patients with otosclerosis with a profound degree of hearing loss and deafness, restoration or correction of hearing with the help of conservative treatment, stapedoplasty or hearing aids does not bring results. Currently, the most effective way of hearing rehabilitation in otosclerosis with deep bilateral hearing loss and deafness is cochlear implantation (CI) [Koroleva IV, 2001, 2002; Lantsov A.A., 2001; Altman Ya.A., 2003; Tavartkiladze G.A., 2013; Peixoto MS, 2013], thanks to which the quality of life of such patients improves in various aspects, such as socialization, etc. [4, 5, 6, 7].

CI has established itself as a “good” option for hearing restoration in patients with cochlear otosclerosis [8, 9, 10]. At the same time, some authors report that not in all cases satisfactory results are achieved in the rehabilitation of patients with otosclerosis with severe hearing loss and deafness after CI [11, 12] due to insufficiently worked out issues related to surgical tactics for this pathology and the peculiarities of rehabilitation hearing (A.N. Marshall, 2005).

When the processor is connected 4-6 weeks after CI, some patients experience pathological stimulation of the facial nerve [14, 15] and deterioration of the results of rehabilitation associated with noise and increased discomfort.

Optimal tuning of the speech processor is the key to successful sound perception for the cochlear implant user.

One of the main settings is the maximum comfortable stimulation level, which is determined in each channel (on each electrode).

As a rule, the first registration of the threshold levels of the stapedial reflex is carried out during the operation of cochlear implantation, and the obtained threshold values of the impulse values are used at the first connection.

For the initial adjustment of the speech processor in implanted patients, the results of the impedance-metric method for recording the acoustic muscle (stapedial) reflex are usually used. In this study, in response to electrical stimulation of the auditory nerve, the contraction of the stapedial muscle occurs, which is not visually recorded under the microscope due to the fact that it is located inside the pyramidal protrusion, but tendon movement is visualized. The reflex threshold levels registered by the channels are used to tune the speech processor. The threshold levels of the stapedial reflex are not the most comfortable levels in the processor's program, however, their values for each channel can be taken as reference points for subsequent adjustment.

Also known from the prior art is a method for recording a stapedial reflex using electromyography (Almqvist B, Harris S, Shallop JK. Objective intraoperative method to record averaged electromyographic stapedius muscle reflexes in cochlear implant patients. Department of Otorhinolaryngology, University Hospital, Lund, Sweden. Audiology, 2000, May-Jun, 39 (3), pp. 146-52). When using this method, a hook-fork with two microneedles at the end is brought to the stapes muscle so that the microneedles cover it from both sides. Then the hook-fork is manually fixed throughout the measurement. To maintain sterility, such a device is disposable. The measurement results are recorded with an electromyography device (Dantec Counterpoint Mk II is used and is used to adjust the speech processor).

The disadvantage of this method is the high cost of disposable instruments, the difficulty of fixing the instrument in a stationary position manually, which creates the likelihood of interference. In this case, the registration of the myogram is performed on the side of the surgical intervention, once, only during the operation, that is, it is impossible to measure the stapedial reflex after the operation.

There is also known a method of electrophysiological telemetry of a nervous response (Dillier N, Lai WK et al. Measurement of the electrically evoked compound action potential via a neural response telemetry system // Ann. Otol. Rhinol. Laryngol, 2002, Vol. 111, N 5, p . 407-414). When using this method, the composite action potential is recorded after the introduction of the chain of electrodes into the cochlea. For this, when a stimulus is applied to one electrode, the evoked potential from the adjacent electrode is recorded. The results of such a survey are used to determine the speech processor tuning map, that is, the configuration of the most comfortable levels in a given processor program.

The disadvantages of this method are: firstly, evoked potentials are recorded only in 80% of patients, and secondly, this method makes it possible to only tentatively set the necessary levels of electrical stimuli for individual channels, that is, the configuration of the stimulation map is approximate.

The closest analogue of the claimed invention is a method for adjusting the parameters of a cochlear implant, described in patent RU No. 2469690, in which during the operation of cochlear implantation, including the supply of stimuli to the electrodes of the cochlear implant and registration of the response in the form of contraction of the tendon of the stapes muscle, according to the proposal, registration is carried out contralaterally , equalizing the pressure in the external auditory canal and middle ear. Also, according to this proposal, registration is carried out in the range from - 100 to +100 mm of water column. The pressure in the middle ear after anesthesia is preliminarily determined, caused by the diffusion of nitrous oxide, which reaches 400-450 mm of water column, which excludes the possibility of direct registration of the stapedial reflex using an impedance meter.

To register the stapedial reflex using an impedance meter, an additional volume of gases is introduced into the pneumatic circuit of the AA220 impedance meter into one liter and a syringe. The additional volume includes a sealed jar with three fittings, while two fittings are connected to the rupture of the tube leading to the impedance meter probe, and a syringe is connected to the third fitting. The pressure change in the pneumatic circuit is carried out with a syringe. Since the gas pressure in the middle ear changes quite rapidly during the operation, it is necessary to shorten the examination time as much as possible.

For this purpose, the registration of the tympanogram is carried out in the range from - 100 mm to +100 mm of water column, bringing the peak of the tympanogram into these limits. This is achieved by changing the pressure in the external auditory canal using a syringe. At the same time, an obturator is inserted into the external auditory canal of a non-operated ear and tympanometry is performed to determine the magnitude of the gas pressure in the middle ear. If the peak of the tympanogram is not observed, then using a syringe increase the pressure by 200 mm H2O and repeat the tympanometry. If no peak is observed again, the pressure is increased by another 100 mm H2O. If the peak of the tympanogram is observed within the tympanometer screen, the reflex is recorded. To register the stapedial reflex, the mode of registration of reflex thresholds, developed by the author - SWEEP, was used. The registration of the stapedial reflex is carried out with sequential stimulation of six implant electrodes - 1, 4, 7, 9, 11 and 12, and the presence or absence of a stapedial reflex in each channel is determined on the impedance meter screen. If a threshold reflex is detected in any channel, the change in the level of stimuli in this channel is not carried out. Where a clear reflex has been found, the stimulation levels are decreased, and where the reflex is absent, the levels are increased. This is continued until the threshold levels of the reflex are recorded in all channels.

The disadvantages of this method are: the impossibility of using the stirrup (ankylosis) when fixing, i.e. with otosclerosis with severe hearing loss and deafness, there are no reflexes, stirrup mobility.

The objective of the present invention is to develop such a method for adjusting the parameters of a cochlear implant, which would be effective in patients with otosclerosis, would be as gentle and at the same time illustrative.

To solve this problem, we proposed a method for adjusting the parameters of a cochlear implant in patients with otosclerosis, which consists in the fact that under local or general anesthesia, an incision is made behind the ear, the area of the mastoid process is exposed within the Shipot triangle, the periosteum with soft tissues is separated from the bones of the skull in the ear region with the formation of the implant bed, antromastoidotomy, posterior tympanotomy, revision of the tympanic cavity with the removal of pathological tissue in the area of the foot plate are performed, then with a diamond bur, the pyramidal process is smoothed from apex to the base until a section of the stapes muscle is exposed up to 8 mm long, then a cochleostomy is formed through which the electrode array of the cochlear implant is introduced into the tympanic ladder, then stimulation is carried out on the electrodes of the cochlear implant and visual registration of the stapedial reflex is carried out by contraction of the stapedial muscle, the appearance of contraction indicates the achievement of the threshold value of the stimulus applied to the electrodes, the cochlear implant is fixed, the wound is sutured in layers.

The technical results of the method are:

- exclusion of the influence of factors that negatively affect the visual registration of the reflex, especially in cases where the reflex cannot be determined intraoperatively by the movement of the tendon of the stapes muscle during otosclerosis due to fixation of the stapes.

- ensuring registration of the stapedial reflex due to direct visualization of the contraction of the stapedius muscle, which is exposed in the most gentle way during the implementation of the method. Improving the visualization of the stapes muscle and its contractions helps to minimize the surgeon's errors during intraoperative adjustment of the speech processor of the cochlear implant at the first connection, and, therefore, to achieve the most comfortable levels of such adjustment. The method is very simple and quickly performed without traumatizing the structures of the middle and inner ear.

The essence of the invention

The method is as follows: under local anesthesia or general anesthesia, a behind-the-ear incision is made, the area of the mastoid process is exposed within the Shipot triangle, the periosteum with soft tissues is separated from the skull bones in the behind-the-ear region with the formation of a bed for the implant, antromastoidotomy is performed, posterior tympanotomy (extended) revision of the tympanic cavity (the condition of the bones, their mobility, the presence of pathological tissue, including otosclerotic foci in the area of the foot plate, whether or not there is transmission to the cochlear window, the condition of the stapes tendon, the severity of the pyramidal process is also determined. Next, a diamond bur is used to smooth out the pyramidal process (from top to base) until the stapes muscle is exposed (up to 8 mm). Further, with pronounced ossification of the cochlear window, a cochleostomy is created, and the electrode array of the cochlear implant is inserted into the tympanic ladder either through the cochleostomy window or through the formed cochleostomy.

Then the visual registration of the stapedial reflex is carried out (we selectively check 2 electrodes of the basal curl, 2 electrodes of the middle curl and 2 of the apical curl) on 1, 4, 7, 9, 11 and 12 electrodes. When a stimulus is applied to one of the electrodes, the surgeon observes through a microscope and reports whether or not he sees the contraction of the stapedial muscle. The appearance of contraction of the stapedial muscle indicates that the threshold value of the stimulus supplied to the electrodes has been reached. If necessary, fix the electrode with a piece of fascia or muscle. Next, the postoperative wound is sutured in layers. Intradermal sutures applied (Vicryl 3-0).

The invention is illustrated by the following figures.

Fig 1. Stages of the reception of exposure of the stapes muscle

A) Location of the pyramidal process to the rest of the anatomical structures of the middle ear;

B) Removal of the bone part of the pyramidal process approximately ~ 8 mm.

B) The direction of the boron movement from the top of the pyramid to the base of the pyramidal process is indicated;

D) Exposed stapes muscle.

CCM - stapes tendon

PO - pyramidal process

CM - stapes muscle

BS - drum string

LN - facial nerve

H - anvil

C - stirrup

Implementation of the invention

The method is illustrated by the following examples.

Example. Patient D., born in 1965 entered the FGBU NKTSO FMBA of Russia in the department of "ear diseases" with a diagnosis of Otosclerosis, mixed form with IV degree of hearing loss and deafness. The patient's condition before the operation is satisfactory. Complaints of hearing loss in both ears, tinnitus. The patient underwent cochlear implantation under general anesthesia. After treatment of the operating field with an alcoholic skin antiseptic under the ETN behind the left ear, 1 cm away from the behind-the-ear fold, an S-shaped incision of the skin and subcutaneous tissue was made with a scalpel. In parallel with the first incision, an incision was made in the soft tissues and periosteum. The area of the mastoid process is exposed within the Shipo triangle. The periosteum with soft tissues is separated from the bones of the skull behind the ear to form a bed for the implant. Under the control of an operating microscope with CarlZeiss optics, a mastoidectomy was performed within the anterior border of the sigmoid sinus and the sino-dural angle with a large cutting bur, tegmenmastoidei, tegmenantri were visualized within the lineatemporalis, smoothed with a diamond bur; the horizontal semicircular canal is visualized; the short process of the incus is visualized. A posterior tympanostomy (tympanotomy) was performed with a diamond bur in the projection of the facial pocket. The niche of the cochlear window, the incus-stapes joint, the pyramidal process with the tendon of the stapes muscle, promontorium were visualized.

Finds: The mucous membrane of the tympanic cavity without inflammation. The stirrup is motionless, the foot plate is thickened. There is no movement between windows.

Further, a tunnel for the electrode array was made with a diamond bur in the cortical layer of the mastoid process, followed by drilling of the transcortical canal into the mastoid cavity.

The canopy over the snail window was removed with diamond burs 1.0 and 1.4; the snail window membrane was ossified. A vertical and then horizontal incision of the secondary membrane of the round window was made with a sickle-shaped knife, then the cochlear window was expanded with boron 1.0 (the membrane is compacted, the capsule of the cochlea is milky, along the axis of the snail window there are otosclerotic foci of white color, dense ones are removed). The ossified areas in the initial sections of the basal curl of the cochlea were removed with a diamond bur and a hook, and the lumen of the tympanic ladder was visualized. The implant is placed subperiosteally in the bed. The grid (straight) Neurelec SAS (N3929) of the active electrode is inserted through the transcortical canal and the posterior tympanostomy into the tympanic ladder up to the level of the restrictive ring. Visual registration of the stapedial reflex by contraction of the stapedial muscle tendon was not possible due to otosclerosis. For this reason, the pyramidal process was smoothed with a diamond bur until an 8 mm section of the stapedius muscle was exposed, then stimuli were applied (2 electrodes of the basal curl, 2 electrodes of the middle curl and 2 of the apical curl were selectively checked) at 1, 4, 7, 9, 11 and 12 electrodes with visual registration of the stapedial reflex under the control of a microscope. When a stimulus was applied to one of the electrodes, the surgeon observed through a microscope and reported whether or not he saw the contraction of the stapedial muscle. When the threshold values of the stimuli were reached, a well-pronounced contraction of the stapes muscle was observed.

Then the postoperative wound was sutured in layers. Intradermal sutures applied (Vicryl 3-0). The condition after the operation is satisfactory, no complaints were noted.

The claimed method was used when setting up a cochlear implant in 9 patients. Thanks to good visualization of contractions of the stapes muscle, it was possible to make a more accurate adjustment of the processor in implanted patients with otosclerosis. In general, the claimed method improves the results of auditory-speech rehabilitation in patients after cochlear implantation.

List of references

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2. Pediatric cholesteatoma: an individualized, single-stage approach / S.C. Parisier, M.B. Hanson, J.C. Han et al. // Otolaryngol Head Neck Surg. - 1996. - Vol. 115, no. 2. - P. 107 - 114.

3. Korvyakov B.C., Diab X.M., Pashchinina O.A, Akhmedov Sh.M. Surgical treatment of patients with cochlear otosclerosis. // Ros otorinol. 2017. No. 5 (90). S. 35-43.

4. Bond M, Mealing S, Anderson R, et al. The effectiveness and costeffectiveness of cochlear implants for severe to prfound deafness in children and adults: a systematic review and economic model. // Health Technol Assess 2009. P. 13.

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Claims (1)

A method for adjusting the parameters of a cochlear implant in patients with otosclerosis, which consists in performing a behind-the-ear incision under local or general anesthesia, exposing the area of the mastoid process within the Shipot triangle, separating the periosteum with soft tissues from the bones of the skull in the region behind the ear to form a bed for the implant, antromastoidotomy, posterior tympanotomy, revision of the tympanic cavity with removal of pathological tissue in the area of the foot plate are performed, then with a diamond bur, the pyramidal process is smoothed from apex to the base until a section of the stapedius muscle is exposed up to 8 mm long, then a cochleostomy is formed, through which an electrode is introduced into the tympanic ladder cochlear implant lattice, then stimulation is carried out on the electrodes of the cochlear implant and visual registration of the stapedial reflex by contraction of the stapedial muscle is carried out, the appearance of contraction indicates that the threshold value of the applied to the electrode Stimulation, the cochlear implant is fixed, the wound is sutured in layers.

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