WO2019197684A1

WO2019197684A1 - A lead anchor device

Info

Publication number: WO2019197684A1
Application number: PCT/EP2019/059713
Authority: WO
Inventors: Ernest Wai Yin LAU
Original assignee: Lau Ernest Wai Yin
Priority date: 2018-04-13
Filing date: 2019-04-15
Publication date: 2019-10-17
Also published as: GB201806115D0; GB201811007D0; GB201817890D0

Abstract

A lead anchor device for use with medical and veterinary lead implants. The lead anchor device can grip a lead body and receive an anchor means such as a suture to anchor a lead to a surface. The lead anchor device dynamically grips a lead body in use such that gripping points move with the lead and the gripping strength acting on the lead can increase or decrease. The lead anchor device also uniformly distributes the gripping force along a section of the lead and can anchor a lead to a surface without the requirement of tying a suture around the lead. The lead anchor device reduces wear and damage to implanted leads when compared to prior art lead anchor devices such as suture sleeves.

Description

A LEAD ANCHOR DEVICE

The present invention relates to an anchor device for a lead, in particular an anchor device that can be used to anchor a lead associated with medical and veterinary implantable electronic devices (MAVIEDs) inside the body.

MAVIEDs such as cardiac pacemakers, implantable cardioverter-defibrillators (ICDs) and neuro-stimulators (the“pulse generators”) are typically implanted in anatomically easily accessible sites within the body (e.g. under the skin, subcutaneous tissues or the pectoralis major muscle in the shoulder region), and may require electric cords (“leads”) containing insulated conductors with one or more electrodes exposed on the surface to connect them (both physically and electrically) to anatomically remote sites in order to perform their intended biologic functions (Lau EW. Leads and electrodes for cardiac implantable electronic devices. In: Ellenbogen KA, Wilkoff BL, Kay GN, Lau CP, Auricchio A, editors. Clinical cardiac pacing, defibrillation and resynchronization therapy. 5 ed. Philadelphia, PA: Elsevier; 2016. p. 313-351 ).

Leads implanted inside the human or animal body are subjected to constant mechanical and chemical stresses and prone to failure over time. A defunct lead may interfere with other leads through clashing of the surface electrodes and mutual abrasion of the surface insulation, obstruct any fluid-filled organs, vessels or foramina (e.g. the heart, a vein, the sub-arachnoid space, an intervertebral foramen) it passes, prevent magnetic resonance imaging from being performed, and may not simply be abandoned inside the body even if it is no longer in active service. An infected lead generally must be removed from the body in order to avoid, control and eradicate“blood poisoning” (septicaemia). Removal of an implanted lead from the body (“extraction”) can be straightforward and requires only manual traction on the lead body. However, it can also be extremely difficult or even dangerous and requires special tools and training if the lead body is heavily encased in fibrous tissues along a course that passes through fluid-filled organs or vessels (Wilkoff BL, et al. Transvenous lead extraction: Heart Rhythm Society expert consensus on facilities, training, indications, and patient management. Heart Rhythm 2009;6:1085-1 104). Lead replacement can be technically challenging, damage other pre-existent leads, and result in infection that may cause systemic illness and even death. There is thus a strong clinical incentive to make leads last as long as possible in service, and as safe and easy to extract as possible if necessary.

Lead conductor failure is generally due to fatigue fracture of the metal filars from repetitive flexing and un-flexing, and most commonly occur around and under the suture sleeve used to fix the lead in place in the surgical pocket (Lau EW. Analysis of pacing and defibrillation lead malfunction. Cardiac Electrophysiology Clinics 2014;6:307-326). Lead insulation failure is most commonly due to mechanical abrasion on the lead surface from the outside by an adjacent lead, the pulse generator, the two ends of a suture sleeve, or an anatomical structure such as a rib, a heart valve, the skull or a transverse process of the spine (outside-in abrasion; Lau EW. Analysis of pacing and defibrillation lead malfunction. Cardiac Electrophysiology Clinics 2014;6:307-326). Less common causes of insulation failure include inside-out abrasion by movement of conductor cables relative to the surrounding insulation within the lead body, environmental stress cracking, and chemical degradation process such as metal-ion induced oxidation and hydrolysis, and "creep" (persistent deformation of a material after mechanical stress has been removed). (Lau EW. Analysis of pacing and defibrillation lead malfunction. Cardiac Electro-physiology Clinics 2014;6:307-326).

It is an object of the invention to mitigate or obviate the problems associated with wear and damage to implanted leads.

It is a further object of the invention to mitigate or obviate the problems associated with suture sleeves, in particular, where suture sleeves cause wear and damage to implanted leads.

According to a first aspect of the invention there is provided a lead anchor device for use with medical and veterinary lead implants, the lead anchor device being operable to grip a lead body and anchor a lead to a surface, the lead anchor device comprising a dynamic grip means, the dynamic grip means being capable of applying a gripping force to a lead body.

Ideally, the dynamic grip means is capable of exerting a force on a lead body at a plurality of gripping points along the length of the lead.

Ideally, the dynamic grip means is capable of gripping a lead body at a plurality of gripping points along the length of the lead.

Preferably, in use, the dynamic grip means is capable of exerting a force on a lead body at a plurality of gripping points spaced apart along the length of the lead body.

Preferably, in use, the dynamic grip means is capable of gripping a lead body at a plurality of gripping points spaced apart along the length of the lead body.

Ideally, the dynamic grip means is shaped such that, when applied to a lead segment, it deforms the lead segment such that the dynamic grip means and the lead segment become interlocked, thereby preventing relative movement between the dynamic grip means and the lead segment.

Advantageously, the interlock fixes the lead segment relative to the dynamic grip means without exerting a significant constrictive force, or any constrictive force, on any portion of the lead body. This is substantially different from the mode of action of suture sleeves which must apply a substantial constrictive force on the lead body to anchor the lead to a surface.

Preferably, in use, the location of the plurality of gripping points along the lead body can remain unchanged as the lead body deforms and moves. Preferably, in use, the location of the plurality of gripping points along the lead body remain unchanged as the lead anchor device deforms and moves under dislodging forces.

Advantageously, the plurality of gripping points ensures that the grip exerted by the lead anchor device on a lead body is not concentrated at any one position along a lead body being anchored by the lead anchor device.

Preferably, in use, the location of the plurality of gripping points along the lead body can remain unchanged relative to and move with the lead body as the lead body deforms and moves.

Preferably, in use, the location of the plurality of gripping points along the lead body can remain unchanged relative to and move with the lead body as the lead body deforms and moves under dislodging forces.

Advantageously, where the lead anchor device is used to anchor a lead of a MAVIED to a recipient’s tissues and the lead body is naturally moved due to movements of the recipient, the plurality of gripping points will correspondingly shift to maintain the location and distribution of the gripping force on the lead body. In situations where the lead body is anchored to the recipient’s tissues by a suture knot or suture sleeve, the entire gripping force is applied constantly to the same portion of the lead body, usually at one or two points along the lead body. This results in wear of the lead at the gripping points, especially when the lead is moved, and eventually breakage can occur. The dynamic grip means obviates this problem.

Ideally, in use, the dynamic grip means applies a non-circumferential gripping force to any length of a lead.

By“non-circumferential” we mean that the gripping force does not extend around a part of the circumference of the lead in use. For example, the gripping force may extend along the lead in a direction that is at an angle to, or parallel to, the axis of the lead. This is in contrast to the prior art suture sleeves wherein the gripping force exerted by the suture on the lead extends around at least a part of the circumference of the lead.

Preferably, the dynamic grip means comprises a lead-holding portion.

Ideally, in use, the plurality of gripping points are exerted by the lead-holding portion.

Ideally, in use, the dynamic grip means is capable of uniformly distributing grip to a lead body.

Ideally, the lead-holding portion is capable of applying a gripping force to a lead.

Ideally, the gripping force exerted by the dynamic grip means on a lead that is anchored by the lead anchor device is positively correlated with the dislodging force acting on the lead.

Ideally, the lead-holding portion comprises an inner diameter.

Preferably, inner diameter of the lead-holding portion is sized to receive a lead, most preferably, a lead for use with a MAVIED. Ideally, the lead-holding portion is extendible.

Preferably, the lead-holding portion is extendible in a longitudinal direction.

Preferably, when the lead-holding portion is extended the inner diameter of the lead- holding portion is reduced.

Ideally, when the lead-holding portion is extended in a longitudinal direction, the inner diameter of the lead-holding portion is reduced.

Ideally, when the lead-holding portion is extended the plurality of gripping points move towards one another in a radial direction.

Advantageously, pulling the lead body segment out of the lead-holding portion proportionally elongates the lead-holding portion and tightens its grip on the held lead body segment. Advantageously again, the grip exerted by the lead-holding portion on the lead body can increase or decrease after a lead has been anchored to a surface. This is in contrast to suture sleeves which exert a constant gripping force on a lead body after application.

Preferably, when the lead-holding portion is extended in a longitudinal direction the plurality of gripping points move apart from one another in a longitudinal direction.

Preferably, the lead-holding portion is arranged at least partially as a helix.

Preferably, the plurality of gripping points are located on the helix.

Advantageously, a helix is longitudinally extendible and compressible.

Ideally, the helix having a variable pitch.

Preferably, the helix can apply a gripping force to a lead.

Ideally, the helix comprises an inner diameter.

Preferably, the helix is sized to receive a lead, most preferably, a lead for use with a MAVIED.

Ideally, the helix is extendible.

Preferably, the helix is extendible in a longitudinal direction.

Preferably, when the helix is extended the inner diameter of the lead-holding portion is reduced.

Preferably, when the helix is extended the inner diameter of the helix is reduced.

Advantageously, pulling the lead body segment longitudinally out of the helix proportionally elongates the helix and tightens its grip on the held lead body segment.

Preferably, the inner diameter of the lead-holding portion is consistent along the length of the lead-holding portion.

Preferably, the inner diameter of the helix is consistent along the length of the helix.

Advantageously, the gripping force is distributed evenly along the lead body being held by the lead-holding portion. Ideally, the lead anchor device is adapted for receiving an anchor means wherein the anchor means may be received without substantially affecting the gripping force of the dynamic gripping means, most preferably of the lead-holding portion.

Advantageously, the force that is applied to a lead in use is largely unaffected by the process of anchoring the lead to a surface.

Ideally, the lead anchor device comprises an anchor portion adapted to be anchored to a surface.

Preferably, the anchor portion extends from the lead-holding portion.

Ideally, at least part of the lead-holding portion is located distal to the anchor portion.

Advantageously, a lead for use with a MAVIED can be fixed to a surface at a distance from the entry point to the body, where at least part of the lead-holding portion is located.

Ideally, the anchor portion is adapted to protect the lead-holding portion from compression.

Ideally, the anchor portion is adapted to receive an anchor means such as a clamp or suture.

Advantageously, the device can be anchored to a surface, including surfaces formed from biological tissues, via the anchor portion alone. This frees the lead-holding portion from any direct anchoring means, such as sutures, which exert a constrictive force on the lead and can cause lead failure in traditional lead anchor devices such as suture sleeves.

Preferably, the lead anchor device is operable to anchor a lead to a surface by applying an anchoring force to the anchor portion, but not the lead-holding portion.

Preferably, the lead anchor device is operable to anchor a lead to a surface by applying an anchoring force directly to the anchor portion, but not directly to the lead-holding portion.

Ideally, the lead anchor device is flexible.

Preferably, the lead-holding portion is flexible.

Ideally, the lead-holding portion having a flexural rigidity equal to or less than that of a lead for use with MAVIEDs.

Preferably, the lead anchor device is formed at least partially from a material having shape memory.

Preferably, the dynamic grip means is formed at least partially from a material having shape memory.

Ideally, the lead anchor device is formed at least partially from a material having shape memory that is superelastic above a transformation temperature.

Preferably, the dynamic grip means is formed at least partially from a material having shape memory that is superelastic above a transformation temperature.

Preferably, the lead anchor device comprises a transformation temperature.

Ideally, the lead anchor device is deformable below the transformation temperature. Preferably, where the lead anchor device is deformed, the lead anchor device returns to a neutral configuration at, about, or above the transformation temperature.

Preferably, wherein the lead anchor device is deformed, the lead anchor device returns to a pre-deformed shape at or about the transformation temperature.

Preferably, the transformation temperature is lower than that of the core temperature of the human or animal recipient of the device.

Preferably, the transformation temperature is equal to or lower than 45°C.

Ideally, the transformation temperature is equal to or lower than 40°C.

Preferably, the transformation temperature is equal to or lower than 37°C.

Advantageously, the lead anchor device is deformable and therefore easy to handle when it is applied to a lead body at a temperature below its transformation temperature, either spontaneously in the ambient temperature ordinary in a clinical operating theatre environment or after cooling in a liquid such as a sterile saline solution. Before complete thermal equilibration with the recipient’s core body temperature, the lead anchor device can still be easily positioned along the lead body. After complete or partial thermal equilibration and even before attainment of the core temperature of the human or animal recipient, the device returns to its pre-deformed shape. The lead-holding portion becomes tightly applied to the intended lead segment and can no longer be easily moved along the lead body. Both the lead-holding portion and the anchor portion become extremely resistant to permanent deformation by virtue of the superelasticity of materials above the transformation temperature and the elastic geometric shapes they are pre- formed into.

In one embodiment, the transformation temperature is equal to or lower than 25°C.

Ideally, the transformation temperature is equal to or lower than 0°C.

Advantageously, in use, the lead-holding portion is tightly applied to the lead segment at a lower temperature than 37°C, and therefore a tight grip occurs before complete thermal equilibration and attainment of the core temperature of the human or animal recipient.

Preferably, the lead-holding portion is elongate.

In one embodiment, the lead-holding portion has a length between 10 mm and 30 mm.

Preferably, the lead-holding portion has a length between 15 mm and 18 mm.

In another embodiment, the lead-holding portion has a length of between 5 mm and 30 mm.

Preferably, the lead-holding portion has a length of between 8 and 10 mm.

Ideally, the lead-holding portion has a length of around 9 mm.

Ideally, the length of the lead-holding portion is extendible by up to 20%.

Ideally, the length of the lead-holding portion is extendible by up to 40%.

Ideally, the length of the lead-holding portion is extendible by up to 60%.

Ideally, the length of the lead-holding portion is extendible by up to 70%. Ideally, the length of the lead-holding portion is extendible by up to 80%.

Ideally, the lead-holding portion can elastically bend up to at least 90°.

Preferably, the lead-holding portion can bend at 90° with a radius of curvature of at least 5 mm.

Preferably, the lead-holding portion can bend at 90° with a radius of curvature of at least 10 mm.

Ideally, in use, a lead which is anchored by the lead anchor device can be bent by 90° about the lead anchor device and have a radius of curvature of at least 15 mm.

Ideally, in use, a lead which is anchored by the lead anchor device can be bent by 90° about the lead anchor device and have a radius of curvature of at least 20 mm.

Advantageously, in use, a lead which is anchored by the lead anchor device can bend about the lead anchor device with a radius of curvature substantially larger than that of a lead anchored by and bent about a suture sleeve. When a lead is anchored by a suture sleeve, the lead typically bends sharply at one end of the suture sleeve at a radius of curvature of only 2-3 mm (the diameter of the lead body). This tight bending accelerates fatigue fracture over time.

Ideally, the lead-holding portion comprises a first end and a second end.

Preferably, in use, the lead-holding portion extends around a lead body and is angled relative to the longitudinal direction of the lead body.

Preferably, the first end and/or the second end of the lead-holding portion is tapered.

Ideally, the first end and/or the second end of the lead-holding portion is tapered in the longitudinal direction of the lead-holding portion.

Ideally, in use, the first end and/or the second end of the lead-holding portion is angled relative to the longitudinal direction of the lead body.

Advantageously, in use, there are is no abrupt transition in rigidity between the lead body segments within and without the lead-holding portion. Advantageously again, the first end and/or the second exert a non-circumferential gripping force on the lead.

Ideally, the lead anchor device comprises no sharp edges.

Ideally, the lead anchor device comprises smoothed and/or rounded edges.

Preferably, the lead anchor device comprises a rounded end.

Ideally, the first end and/or second end of the lead-holding portion comprises a rounded end.

Advantageously, this prevents the ends of the lead anchor device from abrading the lead and/or the surrounding surface to which the lead is anchored or other leads or objects proximal to the device.

Preferably, the lead-holding portion terminates in a closed loop.

Advantageously, there are no sharp ends at the terminal end of the lead-holding portion. Whilst a closed loop is preferable because it is relatively simple to manufacture, other embodiments may be realised, for example a flattened disc-shape, sphere or other smooth geometrical shape.

Ideally, the lead-holding portion terminal end is at least partially curved with an angle of curvature similar or equal to that of the curved surface of the lead body such that the lead- holding portion terminal end lies against the lead body in use.

Preferably, the closed loop extends along and lies against the lead body in use.

Preferably, the closed loop is curved such that it extends along and lies against a lead body in use.

Ideally, the lengthwise and widthwise extension of the lead holding portion is non- planar.

Advantageously, the closed loop does not extend or project out away from the location of the lead body in use.

Ideally, the closed loop is formed by folding a portion of the lead-anchor device over and attaching it to another portion of the lead-anchor device.

Ideally, the closed loop is formed by folding the terminal end of the lead-anchor device over and attaching the terminal end to a portion of the lead-anchor device, most preferably to a portion of the lead-holding portion.

Advantageously, there are no sharp points.

Preferably, the closed loop is formed by welding a portion of the lead-anchor device to itself.

Ideally, the helix is elongate.

Preferably, the helix comprises a first end and a second end.

Ideally, the first end and/or the second end of the helix is non-circumferential.

Preferably, the lead anchor device comprises a neutral configuration wherein the lead anchor device returns to the neutral configuration within a preset neutral configuration temperature range.

Ideally, the preset neutral configuration temperature range is between 30°C and 100°C.

Ideally, the preset neutral configuration temperature range is between 30°C and 80°C.

Ideally, the preset neutral configuration temperature range is between 30°C and 60°C.

Ideally, the preset neutral configuration temperature range is between 30°C and 50°C.

Ideally, the preset neutral configuration temperature range is between 32°C and 45°C.

Ideally, the preset neutral configuration temperature range comprises 37°C.

Advantageously, the lead anchor device can be cooled if necessary and then fitted easily to a lead. After implantation the lead anchor device will warm to the recipient’s core temperature and return to neutral configuration. Preferably, the lead-holding portion, most preferably, the helix, has a neutral configuration inner diameter, the neutral configuration inner diameter being the diameter of the helix when the lead anchor device is at neutral configuration.

Ideally, the lead-holding portion having a neutral configuration length, the neutral configuration length is the length of the lead-holding portion when the lead anchor device is at neutral configuration.

Preferably, the helix having a neutral configuration length, the neutral configuration length is the length of the helix when the lead anchor device is at neutral configuration.

Ideally, the lead-holding portion can extend in a lengthwise direction wherein the length of the lead-holding portion surpasses the neutral configuration length.

Preferably, the helix can extend in a lengthwise direction wherein the length of the helix surpasses the neutral configuration length.

Ideally, the diameter of the lead-holding portion, most preferably, the helix is variable.

Preferably, the lead-holding portion can constrict such that the diameter of the lead- holding portion is less than that of the neutral configuration diameter in at least one section of the lead-holding portion.

Ideally, the helix can constrict such that the diameter of the helix is less than that of the neutral configuration diameter in at least one section of the helix.

Preferably, when the lead-holding portion is extended in a lengthwise direction it correspondingly constricts in at least one section.

Ideally, when the helix is extended in a lengthwise direction it correspondingly constricts in at least one section.

Ideally, in use, the force exerted by the lead anchor device on the lead segment causes the lead segment to deform around the lead anchor device to create an interlock between the lead anchor device and the lead segment.

Preferably, in use, the force exerted by the helix on the lead segment causes the lead segment to deform into the spaces between the turns of the helix, thereby creating an interlock between the lead anchor device and the lead segment.

Advantageously, the helix of the lead anchor device and the helix of the lead segment intertwine and relative movement between the helices is prevented. This provides a fixation mechanism on the lead body that operates by deforming the lead segment into an interlock and does not involve constricting the lead body. Consequently, this reduces the likelihood of wear or damage typically caused by anchors that operate primarily by constricting the lead body.

Advantageously, an extension of the lead-holding portion, which may be caused by, for example, the lead being pulled, causes the diameter decrease, thereby tightening the grip of the lead-holding portion on the lead. The diameter of the lead-holding portion can be configured such that the neutral configuration diameter is only minimally constrictive on the lead, but that when the lead is moved relative to it, the diameter decreases thereby exerting a stronger gripping force on the lead. Therefore, when the lead anchor is in a neutral configuration, the lead is anchored with only minimal force exerted on the lead. When the lead experiences an influence that may dislodge it from its intended position, the lead is anchored with a force positively correlated with the magnitude of the dislodging force. In contrast, suture sleeves exert a constant constrictive force on the lead that tend to be excessive in order to accommodate the maximal dislodging force that the lead can possibly encounter. Such constant excessive constrictive force can permanently deform (“kink”) the conductor filars and insulation in the lead, accelerating fatigue fracture of the conductor filars and abrasion of the insulation.

Ideally, a substantial length of the lead-holding portion, most preferably, the entire length of the lead-holding portion, can exert a constrictive force on a section of a lead located within the lead-holding portion thereby gripping the lead.

Ideally, a substantial length of the helix, most preferably, the entire length of the helix, can exert a constrictive force on a section of a lead located within the helix thereby gripping the lead.

Preferably, in use, the grip exerted on a lead body is evenly distributed throughout the longitudinal span of the lead-holding portion.

Advantageously, the grip is not concentrated at any one point.

Preferably, the lead anchor device is formed at least partially from wire or a wire-like material.

Ideally, the wire or wire-like material comprises a diameter of between 0.25 and 2.0 mm.

Ideally, the wire or wire-like material comprises a diameter of around 0.5 mm.

Advantageously, this provides greater gripping force than wires of a diameter less than

0.5 mm.

In another embodiment, the wire or wire-like material comprises a diameter of around

1.0 mm.

Advantageously, this further increases gripping force of the lead-holding portion relative to thinner-diameter wires.

Ideally, the lead anchor device is formed from a single, continuous piece of wire.

Advantageously, the lead anchor device is simple to manufacture.

Preferably, the lead anchor device is formed from at least one biocompatible and biostable shape memory alloy and/or polymer.

Ideally, the lead anchor device is formed from nitinol wire.

Ideally, the dynamic grip means is formed from a nitinol wire wound and/or annealed into a helix. Preferably, the lead-holding portion is formed from a nitinol wire wound and annealed into a helix.

Ideally, the anchor portion comprises at least one anchor member, most preferably, a plurality of anchor members.

Preferably, the anchor portion can deform.

Ideally, in use, the anchor portion can deform and/or move.

In one embodiment, the anchor portion can move, most preferably pivot, relative to the surface when the lead anchor device is anchored to a surface.

Advantageously, this enhances the movability of the lead after it has been anchored and further reduces the build-up of fibrous tissue around the lead.

Preferably, in use, the anchor portion deforms and/or moves such that the lead-holding portion does not substantially compress when a lead body being held by the lead-holding portion is subjected to certain dislodging forces.

Advantageously, this prevents the diameter of the lead-holding portion from increasing thereby reducing the gripping force. As such, the lead-holding portion can maintain a uniform grip on the lead body even when the lead body is moved in a direction that ordinarily would result in a compression of the lead-holding portion.

Preferably, the at least one anchor member is operable to receive an anchor means such as a clamp, suture or other suitable means for anchoring the anchor portion to a surface.

In one embodiment, the anchor portion extends from a location on the lead-holding portion between the first end and the second end of the lead-holding portion.

Preferably, the anchor portion extends outwards and away from the longitudinal direction of the lead-holding portion.

Ideally, the at least one anchor member extends outwards and away from the longitudinal direction of the lead-holding portion.

Ideally, the helix comprising a longitudinal axis.

Preferably, the at least one anchor member extends outwards and away from the longitudinal axis of the helix.

Preferably, the at least one anchor member extends radially outwards and away from the longitudinal axis of the helix.

Preferably, the at least one anchor member extends at an angle from the longitudinal axis of the lead-holding portion.

Preferably, the at least one anchor member extends at an angle from the longitudinal direction of the lead-holding portion.

Ideally, the at least one anchor member extends at an angle from the longitudinal axis of the helix. Preferably, the angle between the at least one anchor member and the lead-holding portion is equal to or less than 90°.

Preferably, the angle between the at least one anchor member and the helix is equal to or less than 90°.

Ideally, the angle between the at least one anchor member and the lead-holding portion is equal to or less than 45°.

Ideally, the angle between the at least one anchor member and the helix is equal to or less than 45°.

Preferably, the angle between the at least one anchor member and the lead-holding portion is equal to or less than 30°.

Preferably, the angle between the at least one anchor member and the helix is equal to or less than 30°.

Ideally, the angle between the at least one anchor member and the lead-holding portion is variable.

Preferably, in use, when a lead body being held in the lead-holding portion is moved, the angle between the at least one anchor member and the lead-holding portion can be increased or decreased depending on the direction of movement of the lead body.

Advantageously, this mitigates longitudinal compression of the lead-holding portion and therefore the grip of the lead-holding portion on the lead body is not loosened.

Preferably, the angle between the at least one anchor member and the helix is variable.

Ideally, the angle between the longitudinal axis of the at least one anchor member and the longitudinal axis of the helix is variable.

Advantageously, this enhances flexibility of the lead anchor device.

In one embodiment, the anchor portion comprises two anchor members arranged about the lead-holding portion.

In another embodiment, the anchor portion comprises three anchor members arranged about the lead-holding portion defining a tripod.

Ideally, the anchor portion comprises three anchor members arranged about the longitudinal axis of the helix defining a tripod.

Preferably, the anchor portion comprises three anchor members arranged about the lead-holding portion equidistance apart defining a tripod.

Ideally, the anchor portion comprises three anchor members arranged about the longitudinal axis of the helix spaced equidistance apart defining a tripod.

Ideally, the anchor portion comprises three anchor members arranged about the longitudinal axis of the helix spaced equi-angularly apart defining a tripod. Preferably, the at least one anchor member comprises a means for receiving a suture thread.

Ideally, the at least one anchor member comprises a loop, coil, ring, split ring, hook and/or other suitable configuration adapted for receiving a suture.

In one embodiment, the at least one anchor member is elongate.

Preferably, the at least one anchor member extends to a point beyond an end of the lead-holding portion.

Ideally, the at least one anchor member extends to a point beyond the second end of the lead-holding portion.

Ideally, each anchor member extends to substantially the same distance past an end of the lead-holding portion.

In another embodiment, the at least one anchor member comprises a loop, coil, ring, split ring, hook and/or other suitable configuration located at or about an end of the lead-holding portion.

Ideally, the at least one anchor member comprises at least one, most preferably two, turns of a wire or wire-like substance forming an eye adapted to receive a suture needle.

Ideally, the at least one anchor member comprises a ring or ring-like structure formed from at least one, most preferably two, turns of a wire or wire-like substance.

Preferably, the pitch of the turns of the ring or ring-like structure is such that there is less than 0.5 mm between each turn and/or the pitch being such that the turns are adjacent to one another.

Preferably, the turns are tightly coiled such that the turns are adjacent to one another.

Preferably, the ring or ring-like structure is sized to receive a suture needle and thread.

Preferably, the ring or ring-like structure has an opening sized about 1.0 mm.

Ideally, the ring or ring-like structure has an inner diameter of about 1.0 mm.

Preferably, the ring or ring-like structure has an outer diameter of about 2.0 mm.

Ideally, the ring or ring-like structure extends at about 90° to the lead-holding portion.

Preferably, the axis of the ring or ring-like structure is substantially perpendicular to the axis of the lead-holding portion when the lead-holding portion is in a rectilinear orientation.

Ideally, the ring or ring-like structure can pivot relative to the lead-holding portion.

Preferably, the loop, coil, ring, split ring, hook and/or other suitable configuration terminates in a rounded end.

Ideally, the end of the ring or ring-like structure is not mutually opposing the lead- holding portion.

Preferably, the end of the ring or ring-like structure comprises an axis that is substantially parallel to the axis of the lead-holding portion when the lead-holding portion is in a rectilinear orientation. Ideally, the axis of the end of the ring or ring-like structure is spaced apart from the axis of the lead-holding portion.

Ideally, in use, the end of the ring or ring-like structure faces and/or abuts the surface to which the lead anchor device is attached.

Advantageously, this reduces the likelihood that the end will abrade against surrounding tissue, leads or other objects, as it is located close to the surface and not exposed.

In one embodiment, the anchor member is a closed loop.

Ideally in this embodiment the closed loop comprises a single turn of wire.

Advantageously, in use, the single turn of wire in conjunction with an anchor means such as a suture creates a single point pivot whereby the single turn of wire can pivot from a position parallel with the surface to which it is anchored to a position perpendicular to said surface. This flexibility further mitigates lead-abrasion, allows the orientation of the lead to be switched between parallel and perpendicular and provides general movability of the lead after it is anchored to a surface.

Ideally, a part of the anchor portion is attached to itself to form the loop.

Preferably, the wire is attached to itself to form the loop.

Ideally, the attachment is a weld.

Advantageously, there are no sharp points at the anchor portion.

Ideally, the lead anchor device is adapted such that it can anchor a lead that is orientated perpendicular, parallel, or at any angle between perpendicular and parallel, to the surface.

Preferably, the lead anchor device is adapted such that in it can anchor and support a lead that is deployed perpendicular to the surface to which it is anchored.

Preferably, in use, the lead anchor device can be anchored to a surface wherein the lead-holding portion is orientated perpendicular, parallel, or at any angle between perpendicular and parallel, to the surface.

Ideally, the lead anchor device has a means for reducing the risk of rejection of the lead anchor device after implantation.

Preferably, the means for reducing the risk of rejection of the lead anchor device after implantation reduces or prevents exposure of at least part of the lead anchor device to the recipient immune system.

Advantageously, this mitigates the risk of an immune response to the lead anchor device.

Ideally, the means for reducing risk of rejection of the lead anchor device after implantation reduces or prevents dissolution of particles of the lead anchor device.

Preferably, at least part of the lead anchor device has a coating.

Ideally, one or more terminal ends of the lead anchor device are covered by a coating. Advantageously, where the terminal ends are pointed or have sharp edges, the coating can prevent the terminal end from irritating the surface to which the lead anchor device is anchored, or from damaging the lead.

Depending on the composition of the lead anchor device, there may be a risk of rejection of the device upon implantation into a human or animal recipient. Advantageously, the coating reduces or mitigates this risk.

Ideally, the coating at least partially covers the surface of the lead-holding portion and/or the anchor portion.

Preferably, the lead anchor device comprises antimicrobial substances.

Ideally, the coating comprises antimicrobial substances.

Advantageously, this reduces the risk of infection upon implantation.

Ideally, the coating comprises a polymer.

Preferably, the coating is formed from vapour deposition of a polymer.

Preferably, the lead anchor device comprises colouring.

Advantageously, this increase the aesthetic appeal of the lead anchor device.

Ideally, the coating comprises colouring.

Preferably, the coating comprises colour pigmentation.

Ideally, the coating comprises parylene.

In one embodiment, at least one anchor member comprises a coating.

Advantageously, where the anchor member is formed from one or more turns of wire, the coating covers the terminal point of the wire. If the terminal point of the wire is a sharp edge, then the coating can cover the sharp edge and reduce the risk of the anchor member irritating the surrounding surface in use or from damaging the lead.

Ideally, the coating is formed by heat-shrinking a material over the anchor member.

Ideally, the anchor member comprises a stop means to limit movement of a suture about the anchor member.

Preferably, the stop means comprises a physical barrier disposed on the anchor member.

Ideally, the physical barrier is located within the inner boundary of the anchor member.

Preferably, the physical barrier is a drum.

Advantageously, during manufacture of the lead-anchor device, a physical barrier can be disposed within the anchor member and a coating can be fitted over the anchor member thereby retaining the physical barrier within the anchor member.

According to a second aspect of the invention there is provided a lead anchor device for use with medical and veterinary lead implants, the lead anchor device being operable to grip a lead body and anchor a lead to a surface, the lead anchor device comprising a grip means, the grip means being capable of uniformly distributing grip to a lead body.

According to a third aspect of the invention there is provided a lead anchor device for use with medical and veterinary lead implants, the lead anchor device being operable to grip a lead body and anchor a lead to a surface, the lead anchor device being formed at least partially from a material possessing superelastic and/or shape memory properties.

Ideally, the lead anchor device is formed at least partially from nitinol wire.

Advantageously, the lead anchor device is simple to manufacture.

Advantageously again, nitinol wire is superelastic at predetermined temperatures. The lead anchor device is configured to be deformable at temperatures below the device recipient’s body temperature but superelastic at temperatures at or above the device recipient’s body temperature. The lead anchor device is therefore easy to handle and applied to the lead body in the clinical operating theatre, either spontaneously in the ambient temperature ordinary in such an environment or after cooling but will return to its pre-formed neutral configuration with superelasticity after equilibrating to the recipient’s body temperature.

Advantageously again, nitinol has shape memory properties and the lead anchor device can be cooled in a liquid such as a sterile saline solution if necessary, and then easily fitted to a lead. After implantation the lead anchor device will warm to the recipient’s body temperature and return to its pre-formed neutral configuration.

According to a fourth aspect of the invention there is provided a method of anchoring a lead to a surface using a lead anchor device, the lead anchor device being operable to grip a lead body and anchor a lead to a surface, the lead anchor device comprising a dynamic grip means, wherein the method comprises the step of placing a lead in or around the lead anchor device.

Ideally, the method comprises the step of cooling the lead-anchor device.

Ideally, the method comprises the step of cooling the lead-anchor device below the transformation temperature of its constituent shape memory materials.

Preferably, the method comprises the step of unwinding and/or compressing the lead- holding portion.

Ideally, the method comprises the step of positioning a lead within the dynamic grip means such that the dynamic grip means exerts a gripping force on the lead.

Ideally, the method comprises the step of inserting a lead into the lead-holding portion.

Preferably, the method comprises the step of winding the dynamic grip means around the lead. Preferably, the method comprises the step of winding the lead-holding portion around the lead.

Preferably, the method comprises the step of applying an anchor means to the lead- anchor device.

Preferably, the method comprises the step of tying at least one suture to the lead- anchor device.

Ideally, the method comprises the step of applying an anchor means to the anchor portion.

Preferably, the method comprises the step of tying at least one suture to the anchor portion.

Ideally, the method comprises the step of applying an anchor means to at least one anchor member.

Preferably, the method comprises the step of tying at least one suture to at least one anchor means.

Ideally, the method comprises the step of applying the anchor means to an anchorage surface.

Ideally, the method comprises the step of tying at least one suture knot to an anchorage surface.

Advantageously, the anchor means is not applied to the lead-holding portion.

According to a fifth aspect of the invention there is provided a method of anchoring a lead to a surface using a lead anchor device comprising a lead-holding portion capable of receiving a length of a lead, the lead anchor device being operable to grip a lead body and anchor a lead to a surface, the lead anchor device being formed at least partially from a material possessing superelastic and/or shape memory properties, wherein the method comprises the step of placing a lead in or around the lead anchor device.

It will be appreciated that optional features applicable to one aspect of the invention can be used in any combination, and in any number. Moreover, they can also be used with any of the other aspects of the invention in any combination and in any number. This includes, but is not limited to, the dependent claims from any claim being used as dependent claims for any other claim in the claims of this application.

The invention will now be described with reference to the accompanying drawings which shows by way of example only seven embodiments of an apparatus in accordance with the invention.

Figure 1 is a side view of a lead anchor device according to the invention. Figure 2 is a plan view of the lead anchor device in Figure 1.

Figure 3 is a side view of the lead anchor device shown in Figure 1 in use, the lead anchor device anchoring a lead perpendicularly to a surface, the surface is illustrated by hatching.

Figure 4 is a plan view of the lead anchor device in Figure 3.

Figure 5 is a side view of the lead anchor device shown in Figure 1 in use, the lead anchor device anchoring a lead perpendicularly to a surface and being bent in the direction of the arrow, the surface is illustrated by hatching.

Figure 6 is a side view of the lead anchor device shown in Figure 1 in use, the lead anchor device anchoring a lead perpendicularly to a surface and the lead being moved in the direction of the arrow away from the surface, the surface is illustrated by hatching.

Figure 7 is a side view of the lead anchor device shown in Figure 1 in use, the lead anchor device anchoring a lead perpendicularly to a surface and the lead being moved in the direction of the arrow away from the surface, the surface is illustrated by hatching.

Figure 8 is a perspective view of the lead anchor device shown in Figure 1 in use, the lead anchor device anchoring a lead parallel to a surface, the surface is illustrated by hatching.

Figure 9 is perspective view of a second embodiment of a lead anchor device in use, the lead anchor device anchoring a lead parallel to a surface and having a longer lead-holding portion than the lead anchor device in Figures 1 to 8, the surface is illustrated by hatching.

Figure 10 is a side view of a third embodiment of a lead anchor device according to the invention.

Figure 1 1 is a side view of the lead anchor device shown in Figure 10 rotated anticlockwise by 90°.

Figure 12 is a side view of the lead anchor device shown in Figure 10 rotated anticlockwise by 180°.

Figure 13 is a side view of the lead anchor device shown in Figure 10 rotated anticlockwise by 270°.

Figure 14 is a plan view of the lead anchor device shown in Figure 10.

Figure 15 a side view of the lead anchor device shown in Figure 10 in use, the lead anchor device anchoring a lead perpendicularly to a surface, the surface is illustrated by hatching.

Figure 16 is a rotated side view of the lead anchor device shown in Figure 15 wherein the lead is bent by 90°, the surface is illustrated by hatching.

Figure 17 is a side perspective view of the lead anchor device shown in Figure 10 in use, the lead anchor device anchoring a lead parallel to a surface, the surface is illustrated by hatching. Figure 18 is a top perspective view of the lead anchor device shown in Figure 10 in use, the lead anchor device anchoring a lead parallel to a surface, the surface is illustrated by hatching.

Figure 19 is top perspective view of a fourth embodiment of a lead anchor device in use, the lead anchor device anchoring a lead parallel to a surface and having a longer lead-holding portion than the lead anchor device in Figures 10 to 18, the surface is illustrated by hatching.

Figure 20 is a side view of a fifth embodiment of a lead anchor device according to the invention.

Figure 21 is a side view of the lead anchor device shown in Figure 20 rotated anticlockwise by 90°.

Figure 22 is a side view of the lead anchor device shown in Figure 20 rotated anticlockwise by 180°.

Figure 23 is a side view of the lead anchor device shown in Figure 20 rotated anticlockwise by 270°.

Figure 24 is a plan view of the lead anchor device shown in Figure 20.

Figure 25 is a side view of the lead anchor device shown in Figure 20 in use, the lead anchor device anchoring a lead perpendicularly to a surface, the surface is illustrated by hatching.

Figure 26 is a side view of the lead anchor device shown in Figure 20 in use, the lead anchor device anchoring a lead perpendicularly to a surface, the lead being bent.

Figure 27 is a side perspective view of the lead anchor device shown in Figure 20 in use, the lead anchor device anchoring a lead parallel to a surface.

Figure 28 is a top perspective view of the lead anchor device shown in Figure 27 in use, the lead anchor device anchoring a lead parallel to a surface, the surface is illustrated by hatching.

Figure 29 is top perspective view of a sixth embodiment of a lead anchor device in use, the lead anchor device anchoring a lead parallel to a surface and having a longer lead-holding portion than the lead anchor device in Figures 20 to 28, the surface is illustrated by hatching.

Figure 30 is a side view a seventh embodiment of lead anchor device along with two stoppers before they have been incorporated into the device.

Figure 31 is the lead anchor device of Figure 30 with the stoppers positioned within the end portions of the device.

Figure 32 is the lead anchor device of Figure 31 wherein the stoppers have been secured by a coating.

Figure 33 is the lead anchor device of Figure 32 deployed perpendicular to a surface.

Figure 34 is the lead anchor device of Figure 32 deployed parallel to a surface. Figure 35 is a side view of the lead anchor device in use, the lead anchor device anchoring and being intertwined with the lead.

In Figures 1 to 8 there is shown a lead anchor device indicated generally by reference numeral 1 for use with medical and veterinary lead implants. The device 1 has a dynamic grip arrangement 10, the dynamic grip arrangement 10 having a lead-holding portion 2 capable of receiving a length of a lead 3 as shown in Figures 3 to 8. The lead anchor device further has an anchor portion 4. The anchor portion 4 extends from the lead-holding portion 2 and is adapted to be anchored to a surface as shown in Figures 3 to 8. As the anchor portion 4 extends from the lead-holding portion 2, it is possible to anchor the lead anchor device 1 to a surface by tying a suture knot to the anchor portion 4 and not around the lead-holding portion 2 or the lead (as is required when using suture sleeves; see Figures 3 to 8). The lead anchor device 1 can be used to anchor a lead from a MAVIED to the device recipient’s tissues by applying a constrictive force to the anchor portion 4 but not the lead-holding portion 2.

The lead anchor device 1 is formed from a single, wound length of nitinol wire and has shape memory and superelastic properties. It is configured to return to a preformed shape and be superelastic at 0°C. The lead-holding portion 2 is elongate and helical, having a first end 8 and a second end 9 and is sized to receive a lead for use with a MAVIED. Accordingly, whilst the lead-holding portion 2 is easily deformable in a clinical operating theatre environment either spontaneously or after cooling in a liquid such as a sterile saline solution, it returns to its pre- formed shape when warmed, for example, by the recipient’s body, and exerts on the lead body a gripping force positively correlated with the dislodging force. In addition, the lead-holding portion 2 is longitudinally extendible and protected from compression by the anchor portion 4. The lead-holding portion 2 can elastically bend up to at least 90°.

The lead anchor device 1 has a neutral configuration as shown in Figures 1 and 2 whereby, when the lead anchor device is deformed, the lead anchor device 1 returns to the neutral configuration by virtue of the superelasticity of its constituent materials at the recipient’s body temperature, which is 37°C for humans. The lead-holding portion 2 has a neutral configuration inner diameter, being the inner diameter of the lead-holding portion 2 in its neutral configuration, and a neutral configuration length, being the length of the lead-holding portion 2 in its neutral configuration. The neutral configuration length of the lead-holding portion 2 of the lead anchor device 1 shown in Figures 1 to 8 is 15 mm.

The lead-holding portion 2 can extend in a lengthwise direction wherein the length of the lead-holding portion 2 surpasses the neutral configuration length and is protected by the anchor portion 4 from compression in a lengthwise direction wherein the length of the lead- holding portion 2 is less than the neutral configuration length. The lead-holding portion 2 can also constrict, wherein the diameter of the lead-holding portion 2 is less than that of the neutral configuration diameter. When the lead-holding portion 2 is extended in a lengthwise direction the diameter decreases. The lead-holding portion is wound into a helical shape.

The anchor portion 4 comprises three anchor members 5, 6, 7 arranged equidistance apart around the lead-holding portion 2 defining a tripod. The anchor members 5, 6, 7 are configured as a loop to receive a suture and extend outwards at an angle from the lead holding portion 2. The anchor members 5, 6, 7 are elongate and vary in length but all extend to the same distance past the second end 9 of the lead-holding portion 2. The superelasticity of the lead anchor device 1 enables the anchor members 5, 6, 7 to bend drastically about the point of connection with the lead-holding portion 2 and still return to their neutral configurations after the deforming influence has ceased.

In use, the lead-holding portion 2 of the lead anchor device 1 can be widened by hand, longitudinally compressed or even straightened and then wrapped around a lead to be implanted within the human or animal recipient. The lead anchor device 1 is then anchored to a surface, such as the tissue of the recipient, by threading a suture thread through at least one anchor member 5, 6, 7 and the surface and tying a suture knot. The lead anchor device 1 may be chilled during this step to ensure that it does not reach the temperature at which it returns to the neutral configuration (37°C for a human recipient) before a lead has been inserted into the lead-holding portion 2. Once the lead is positioned within the lead-holding portion 2 and the lead anchor device 1 is at the recipient’s body temperature, the neutral configuration will grip the lead 3 as shown in Figures 3 to 8. The effect of movement of the lead body 3 on the shape and configuration of the lead anchor device 1 is illustrated in Figures 5 to 7. The lead body 3 can be bent by 90° as shown in Figure 5 with a large radius of curvature. The plurality of gripping points of the dynamic grip arrangement 10 are maintained through this movement. When the lead body 3 is pulled away from the surface to which the lead anchor device 1 is anchored, the angle between the anchor portion 4 and the lead-holding portion 2 is decreased and the anchor portion 4 folds inwards against the lead body 3 (Figure 6). The plurality of gripping points of the dynamic grip arrangement 10 are maintained. When the lead body 3 is moved towards the surface at which the lead anchor device 1 is anchored, the angle between the anchor portion 4 and the lead-holding portion 2 is increased and the anchor portion 4 is forced outwards and away from the lead body 3. This prevents compression of the lead-holding portion 2 and correspondingly it prevents a loosening of grip on the lead body 3.

A lead 3 which is anchored by the lead anchor device 1 can be bent by 90° about the lead anchor device 1 and have a radius of curvature of at least 15 mm (see Figure 5). This radius of curvature is substantially larger than the radius of curvature that is achieved with a lead that bent by 90° about a suture sleeve, which is typically in the region of 2-3 mm and includes a sharp bend. Such severe deformation of the lead at the ends of the suture sleeve is a common cause of lead failure encountered in clinical practice. If the lead is pulled, the diameter of the lead-holding portion 2 constricts thereby tightening the grip of the lead-holding portion on the lead. The diameter of the lead-holding portion 2 is configured such that the diameter of the lead-holding portion 2 in the neutral configuration is only minimally constrictive on the lead 3, but that when the lead 3 is pulled the diameter of the lead-holding portion 2 constricts thereby exerting a stronger gripping force positively correlated with the force pulling on the lead 3. Therefore, in the absence of any dislodging force, the lead 3 is anchored but there is very little force exerted on the lead. The grip exerted on a lead 3 is evenly distributed throughout the longitudinal span of the lead-holding portion 2 and is not concentrated at any one point. The angle between each of the anchor members 5, 6, 7 and the lead-holding portion 2 is subject to fluctuation due to the flexibility of the lead anchor device 1. The lead anchor device 1 can be anchored to a surface wherein the lead-holding portion 2 extends perpendicularly to the surface, as shown in Figures 3 to 7; or parallel to the surface, wherein the lead-holding portion 2 extends parallel to the surface, as shown in Figure 8.

The lead anchor device 1 is formed by folding a piece of a wire to create two turns of a helix, then a first anchor member 7 shaped as a hairpin loop, then a further partial turn of a helix and a second anchor member 6 shaped as a hairpin loop, then a further partial turn of a helix and a third anchor member 5 shaped as a hair pin loop. A further two turns of a helix complete the lead-holding portion 2.

In the embodiment shown in Figure 9 there is a lead anchor device indicated generally by reference numeral 101 and having a dynamic grip arrangement 110 with a lead-holding portion 102 capable of receiving a length of a lead 103, the lead anchor device 101 further having an anchor portion 104. The anchor portion 104 extends from the lead-holding portion 102 and is adapted to be anchored to a surface. The lead-holding portion 102 further has a neutral configuration length of 22 mm. The lead-holding portion 102 has an additional four helical turns when compared with the embodiment illustrated in Figure 8.

In the embodiment shown in Figures 10 to 18 there is a lead anchor device indicated generally by reference numeral 201 with a dynamic grip arrangement 210 and a lead-holding portion 202 capable of receiving a length of lead 203. The lead anchor device 201 further has an anchor portion 204. The lead-holding portion 202 has a length of 9 mm and terminates in a rounded end 215. The lead anchor device 201 is formed from nitinol wire with a diameter of 0.5 mm. The anchor portion 204 comprises a circular ring-like structure 216 formed at the terminal end of the lead-holding portion 202. The ring-like structure 216 extends from the lead-holding portion 202, bent at 90° relative to the axis of the lead-holding portion 202. The ring-like structure 216 is formed from two complete turns of nitinol wire with the pitch of the turns such that the wire in each turn is abutting the wire in the adjacent turn. The ring-like structure 216 has an outer diameter of 2.0 mm and an inner diameter of 1.0 mm. The ring-like structure 216 terminates in a rounded end 217 which, in use, faces towards and/or abuts the surface to which the lead anchor device 201 is anchored.

In use, as shown in Figures 15 to 18, the lead 203 is inserted into the lead-holding portion 202 as outlined above for the embodiment shown in Figures 1 to 8. A suture thread is then then threaded through the ring-like structure 216 and into the surface to which the lead 203 is to be anchored and a suture knot 218 is tied about the ring-like structure 216. It is possible to deploy the lead-anchor device 201 either parallel to the surface, wherein the axis of the lead- holding portion 202 extends parallel to the surface (see Figures 17 and 18), or perpendicular to the surface (Figures 15 and 16). Deploying the lead-anchor device 201 perpendicularly provides an upright structural support for the lead 203. The lead 203 can be bent towards a location that is elevated from the surface, for example, the top of a pulse generator where it is desired to implement a lead-top arrangement. The radius of curvature in the bend of the lead 203 from the surface to the elevated location is gradual and is determined by the helical lead-holding portion 202. No sharp bends from the surface to the elevated location occur.

In the embodiment in Figure 19 there is shown a lead-anchor device 301 with a lead- holding portion 302 of extended length. The lead-holding portion 302 has nine turns and a length of 27 mm.

In Figures 20 to 28 there is shown a fifth embodiment of a lead-anchor device indicated generally by reference numeral 401. The lead-holding portion 402 terminates in a circular ring 430 that is formed during manufacturing by folding the end of the lead-holding portion 402 over and welding it to itself. The lead-holding portion 402 has three turns and is formed from nitinol wire with a diameter of 0.5 mm. The total length of the lead-anchor device 401 is 12 mm and the pitch of the helical portion is 3 mm. The anchor portion 404 is formed from a single ring of nitinol wire welded to itself forming a coil of inner diameter 1.5 mm and an outer diameter of 2.5 mm. The anchor portion 404 is arranged such that the axis of the ring is perpendicular to the axis of the lead-holding portion 402. The anchor portion 404 projects at 90° to the lead-holding portion 402. This means that the suture or other anchor means is located away from the lead body in use thereby reducing the likelihood of lead body-suture abrasion. The lead-anchor device 401 can be deployed perpendicularly to a surface as shown in Figures 25 and 26 or perpendicular to a surface as shown in Figures 27 to 28.

Figure 29 is a sixth embodiment of a lead-anchor device according to the invention indicated by reference numeral 501. The lead-anchor device 501 is similar to the fourth embodiment of the lead-anchor device 401 , differing in that the lead-holding portion 502 is formed from nine turns and is three times longer than the lead-holding portion 402.

Figures 30 to 34 show a seventh embodiment of a lead-anchor device according to the invention, indicated generally by reference numeral 601. The lead-anchor device 601 has two terminal ends 650a, 650b formed from three tightly wound turns of nitinol wire. Each terminal end 650a, 650b can be adapted as an anchor portion 604 that can receive a suture for anchoring the device 601 to a surface. The lead-anchor device 601 further has a lead-holding portion 602 extending between the terminal ends 650a, 650b. The lead-anchor device 601 has two stoppers 651 a, 651 b that are operable to prevent a suture from slidably moving along the anchor portion 604 after the device 601 has been anchored (see Figure 33). The stoppers 651 a, 651 b are formed from polymer drums and are located within the inner boundary of each terminal end 650a, 650b. Each terminal end 650a, 650b also has a cover 652a, 652b formed from a heat-shrunk polymer that extends around the entirety of the outer surface of the terminal end 650a, 650b. During manufacture of the lead-anchor device 601 , a separator (not shown), such as a metal disc, can be inserted between turns of the terminal end 650a, 650b and extending through the stopper 651a, 651 b. After the cover 652a, 652b has been applied, the separator can be removed. This forms an anchor portion 604 with a divided stopper 651 a, 651 b as shown in Figures 33 and 34. Alternatively, the stopper 651a, 651 b can be cut into two separate pieces after manufacture. The two parts of the stopper 651 b can be hinged apart as shown in Figures 33 and 34 and a suture can be applied to the anchor portion 604 between the two parts of the stopper. The suture cannot slide along the anchor portion 604 as it is prevented from doing so by the stopper 651 b. The stopper is further held in place by the cover 652b and the cover 652b covers the end of the nitinol wire such that the lead anchor device 601 has no sharp edges.

Referring to the drawings and now to Figure 35,_the lead anchor device 700 on the lead segment 700 causes the lead segment 701 to deform around the lead anchor device 700 to create an interlock being and interweave between the lead anchor device 700 and the lead segment 701. In use, the force exerted by the lead anchor device 700 in the form of a helix on the lead segment 701 causes the lead segment 701 to deform into the spaces between the turns of the helix 700, thereby creating an interlock/interweave between the lead anchor device 700 and the lead segment 701.

Advantageously, the helix 700 of the lead anchor device 700 and the helix of the lead segment 701 intertwine and relative movement between the helices is prevented. This provides a fixation mechanism on the lead body 701 that operates by deforming the lead segment 701 into an interlock/interweave and does not involve constricting the lead body 701. Consequently, this reduces the likelihood of wear or damage typically caused by anchors that operate primarily by constricting the lead body.

In the preceding discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of the values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of the parameter, lying between the more preferred and the less preferred of the alternatives, is itself preferred to the less preferred value and also to each value lying between the less preferred value and the intermediate value.

The features disclosed in the foregoing description or the following drawings, expressed in their specific forms or in terms of a means for performing a disclosed function, or a method or a process of attaining the disclosed result, as appropriate, may separately, or in any combination of such features be utilised for realising the invention in diverse forms thereof as defined in the appended claims.

Claims

1. A lead anchor device for use with medical and veterinary lead implants, the lead anchor device being operable to grip a lead body and anchor a lead to a surface, the lead anchor device comprising a dynamic grip means, the dynamic grip means being capable of applying a gripping force to a lead body.

2. A lead anchor device as claimed in claim 1 wherein the dynamic grip means is capable of gripping a lead body at a plurality of gripping points along the length of the lead.

3. A lead anchor device as claimed in claims 1 or 2 wherein the dynamic grip means is shaped such that, when applied to a lead segment, it deforms the lead segment such that the dynamic grip means and the lead segment become interlocked, thereby preventing relative movement between the dynamic grip means and the lead segment.

4. A lead anchor device as claimed in claims 2 or 3 wherein, in use, the location of the plurality of gripping points along the longitudinal length of the lead body can remain unchanged as the lead body deforms and moves.

5. A lead anchor device as claimed in any preceding claim wherein, in use, the dynamic grip means applies a non-circumferential gripping force to any length of the lead.

6. A lead anchor device as claimed in any preceding claim wherein the gripping force exerted by the dynamic grip means on a lead that is anchored by the lead anchor device is positively correlated with the dislodging force acting on the lead.

7. A lead anchor device as claimed in any preceding claim wherein the lead anchor device is adapted such that it can anchor a lead that is orientated perpendicular, parallel, or at any angle between perpendicular and parallel, to the surface.

8. A lead anchor device as claimed in claim 7 wherein the lead anchor device is adapted such that it can anchor and support a lead that is deployed perpendicular to the surface to which it is anchored.

9. A lead anchor device as claimed in any preceding claim wherein the dynamic grip means comprises a lead-holding portion that is capable of applying a gripping force to a lead.

10. A lead anchor device as claimed in claim 9 wherein the lead-holding portion is extendible.

11. A lead anchor device as claimed in claim 10 wherein when the lead-holding portion is extended the inner diameter of the lead-holding portion is reduced.

12. A lead anchor device as claimed in claims 10 or 1 1 wherein when the lead-holding portion is extended the plurality of gripping points move towards one another in a radial direction.

13. A lead anchor device as claimed in any one of claims 9 to 12 wherein the lead-holding portion is arranged at least partially as a helix.

14. A lead anchor device as claimed in claim 13 wherein, in use, the force exerted by the helix on the lead segment causes the lead segment to deform into the spaces between the turns of the helix thereby creating an interlock between the lead anchor device and the lead segment.

15. A lead anchor device as claimed in any one of claims 9 to 14 wherein the lead-holding portion terminates in a closed loop.

16. A lead anchor device as claimed in any preceding claim wherein the lead anchor device is adapted for receiving an anchor means such as a clamp, suture or other suitable means.

17. A lead anchor device as claimed in claim 16 when dependent on claim 9 wherein the anchor means may be received without substantially affecting the gripping force of the lead-holding portion.

18. A lead anchor device as claimed in any preceding claim comprising an anchor portion adapted to be anchored to a surface.

19. A lead anchor device as claimed in claim 18 wherein the anchor portion extends from the lead-holding portion.

20. A lead anchor device as claimed in claim 18 or 19 wherein the lead anchor device is operable to anchor a lead to a surface by applying an anchoring force to the anchor portion, but not the lead-holding portion.

21. A lead anchor device as claimed in any one of claims 18 to 20 wherein the anchor portion comprises at least one anchor member operable to receive an anchor means such as a clamp, suture or other suitable means for anchoring the anchor portion to a surface.

22. A lead anchor device as claimed in claim 21 wherein the at least one anchor member comprises a loop, coil, ring, split ring, hook and/or other suitable configuration located at or about an end of the lead-holding portion.

23. A lead anchor device as claimed in claims 21 or 22 wherein the anchor member is a closed loop.

24. A lead anchor device as claimed in any preceding claim wherein the lead anchor device is formed at least partially from a material having shape memory.

25. A lead anchor device as claimed in claim 24 wherein the lead anchor device comprises a transformation temperature wherein the lead anchor device is deformable below the transformation temperature but returns to a neutral configuration at, about, or above the transformation temperature.

26. A lead anchor device as claimed in claim 25 wherein the transformation temperature is equal to or lower than 37°C.

27. A lead anchor device as claimed in any preceding claim wherein the lead anchor device is formed at least partially from wire or a wire-like material.

28. A lead anchor device as claimed in claim 27 wherein the lead anchor device is formed from nitinol wire.

29. A lead anchor device as claimed in any preceding claim wherein at least part of the lead anchor device has a coating.