The present invention generally relates to surgical instruments for medical implants and, more particularly, the invention relates to surgical instruments for implantable electrode carriers that improve the insertion process of the electrode carriers.
For many patients with severe to profound hearing impairment, there are several types of middle-ear and inner-ear implants that can restore a sense of partial or full hearing. For example, cochlear implants can restore some sense of hearing by direct electrical stimulation of the neural tissue of the inner ear or cochlea. The cochlear implant typically includes an electrode carrier having an electrode lead and an electrode array, which is threaded into the cochlea. The electrode array usually includes multiple electrodes on its surface that electrically stimulate auditory nerve tissue with small currents delivered by the electrodes distributed along the electrode array. These electrodes are typically located toward the end of the electrode carrier and are in electrical communication with an electronics module that produces an electrical stimulation signal for the implanted electrodes to stimulate the cochlea.
One of the important steps in cochlear implant surgery is the insertion of the electrode array into the scala tympani of the cochlea. In some cases, this insertion process can be disrupted when the continuous movement of the electrode carrier into the cochlea gets disturbed due to increased frictional forces between the cochlea wall and the electrode array, or due to small obstacles preventing the electrode carrier from smoothly moving along the insertion path. In both cases, the electrode carrier may become damaged if it is excessively bent when being pushed further inside the cochlea while the tip or other parts of the electrode carrier are prevented from moving forward. Furthermore, x-ray microscopy studies by Hüttenbrink et al. allowed a visualization of the frictional behaviour of electrodes in the inner ear and revealed that in some cases there might be the danger of kinking of the electrode carrier inside of the scala tympani. A subsequent contact pressure between electrode and basilar membrane which may lead to rupture of the basilar membrane is very likely to damage anatomical structures of the inner ear and destroy residual hearing. Such damage is not acceptable with the latest trends in Electric Acoustic Stimulation (EAS) technology and cochlear implant surgery to preserve any residual hearing.
To minimize these problems, lubricating substances are sometimes used on the electrode carrier to reduce the frictional forces between electrode carrier and the cochlea. However, it is questionable whether these lubricating substances are able to prevent typically occurring problems during the insertion process and currently have not become a commonly accepted clinical practice.
Another issue which is observed in cochlear implant surgery is the floppiness of the electrode carrier in the mastoidectomy and posterior tympanatomy which may make it difficult to guide the electrode carrier to the cochleostomy or round window without picking up blood or other fluids from the surrounding tissues. A contamination of the electrode carrier with blood represents another potential hazard to the residual hearing of patients.
U.S. Patent Application Publication No. 2007/0225787 to Simaan et. al. (“Simaan”) teaches active-bending electrodes and corresponding insertion systems for inserting same. In this context, an electrode applicator is mentioned which reduces the frictional forces as the electrode traverses the inner ear by applying vibrations to the electrode array. However, the insertion systems disclosed therein include a controller located remotely, making the systems bigger and more unwieldy. In addition, Simaan fails to provide any teachings on how, and by what mechanism, the insertion system generates the vibrations in the electrode array.
In accordance with one embodiment of the invention, a surgical instrument for inserting an implantable electrode carrier includes a housing having a proximal end and a distal end. The proximal end is configured to hold the implantable electrode carrier. The instrument also includes a vibration generator positioned within the housing. The vibration generator is configured to generate vibrations in at least a portion of the electrode carrier.
In related embodiments, the vibration generator may be positioned within the distal end and/or the proximal end of the housing. The instrument may further include a power supply coupled to the vibration generator and positioned within the housing, such as the distal end of the housing. The power supply is configured to supply energy to the vibration generator. The vibration generator may include a floating mass transducer. The floating mass transducer may include a bushing having an inner area, a permanent magnet positioned within the inner area of the bushing, and an electromagnetic coil adjacent to a portion of the bushing. The electromagnetic coil is configured to move the permanent magnet within the inner area of the bushing. The floating mass transducer may further include one or more springs positioned between the permanent magnet and one end of the bushing so that the spring(s) are configured to move the permanent magnet back to a neutral position after the electromagnetic coil moves the permanent magnet within the inner area of the bushing. The permanent magnet may be cylindrical or spherical in shape.
The vibration generator may include an electromotor connected to a gear, and a mass connected to the gear. The mass is configured to produce at least a portion of the vibrations generated by the vibration generator when the gear moves the mass. Alternatively, or in addition, the vibration generator may include an electromotor connected to a gear having an unbalanced mass. The unbalanced mass is configured to produce at least a portion of the vibrations generated by the vibration generator when the gear moves the unbalanced mass. The instrument may further include one or more sensors positioned near the distal end of the housing. The sensor(s) may be configured to sense a force applied to the instrument, and the vibration generator may be configured to control vibrations parameters based on the sensed force. The vibration generator may impart longitudinal oscillations, transverse oscillations and/or rotational oscillations to the proximal end of the housing. The vibration generator may include a piezoelectric actuator, a pneumatic actuator, an hydraulic actuator, an electrodynamic actuator and/or a mechanical actuator. The housing may have a longitudinal axis from the proximal end to the distal end of the housing, and the vibration generator may be concentric to the longitudinal axis or offset from the longitudinal axis.
In accordance with another embodiment of the invention, a method of making a surgical instrument for inserting an implantable electrode carrier includes providing a housing having a proximal end and a distal end, and providing a vibration generator positioned within the housing. The proximal end is configured to hold the implantable electrode carrier, and the vibration generator is configured to generate vibrations in at least a portion of the electrode carrier.
In related embodiments, the method may further include providing a power supply coupled to the vibration generator and positioned within the housing. The power supply is configured to supply energy to the vibration generator. The vibration generator may include a floating mass transducer that has a bushing having an inner area, a permanent magnet positioned within the inner area of the bushing, and an electromagnetic coil adjacent to a portion of the bushing. The electromagnetic coil is configured to move the permanent magnet within the inner area of the bushing. The vibration generator may include an electromotor connected to a gear having an unbalanced mass, and the unbalanced mass may be configured to produce at least a portion of the vibrations generated by the vibration generator when the gear moves the unbalanced mass. The method may further include providing one or more sensors positioned near the distal end of the housing. The one or more sensors are configured to sense a force applied to the instrument, and the vibration generator is configured to control vibration parameters based on the sensed force.
The foregoing features of the invention will be more readily understood by reference to the following detailed description, taken with reference to the accompanying drawings, in which:
Various embodiments of the present invention provide a surgical instrument for inserting an implantable electrode carrier, methods of making same, and methods of inserting the electrode carrier, that improves the current implantation process for electrodes. The surgical instrument includes a housing and a vibration generator which is integrated into the housing. The vibration generator is configured to generate vibrations in at least a portion of the electrode carrier. Details of illustrative embodiments are discussed below.
Embodiments of the instrument 120 may also include a power supply 126 positioned within the housing 122 and coupled to the vibration generator 124. Preferably, the power supply 126 is positioned within the distal end of the housing 122. The power supply 126 supplies energy to the vibration generator 124. The instrument 120 may include a standard instrument handle 128 at the distal end of the housing 122 which allows a surgeon to grip the instrument, guide it and the cochlear implant electrode carrier to the cochleostomy, and insert the electrode array into the cochlea. Although one configuration of the instrument 120 is shown, any standard instrument geometry may be used, e.g., forceps, tweezers, or surgical claws, that allows an integrated vibration generator 124.
Embodiments of the instrument 120 may also include one or more sensors (not shown) positioned on or in the housing 122. The sensor(s) may be used to detect a force which is applied to the instrument 120, and the sensed force may be used as an input for the vibration generator 124. The sensor(s) may be used to give surgeons the ability to control various vibration parameters generated by the vibration generator 124 (e.g., an increased pressure on the handle of the instrument by the surgeon may increase the amplitude and/or frequency of the vibrations). This may allow surgeons to implement the instrument and its vibrations in a much more controlled way. A stopper (not shown) may also be used with the instrument 120 to prevent overloading of the electrode carrier caused by any high closing forces of the instrument 120.
Embodiments of the vibration generator 124 are configured to couple vibrations to at least a portion of the electrode carrier. The frequency and amplitude of the vibrations produced by the vibration generator 124 are preferably chosen such that the oscillations produced in the electrode carrier help to overcome the friction effects and obstacles encountered when inserting the electrode carrier into the cochlea, reducing possible insertion trauma. In addition, or alternatively, the vibrations may be adapted to the vibration characteristics of one or more portions of the electrode carrier such that any large amplitude deflections of the electrode carrier may be suppressed or substantially suppressed. The instrument 120 may have one or more different vibration modes to provide optimal behaviour of the electrode carrier inside and outside the cochlea. The vibration parameters may be optimized to improve the electrode carrier movement, to improve the stability of the electrode carrier (e.g., to avoid transversal oscillations of a floppy electrode carrier), and/or to improve the smoothness of the electrode carrier insertion process. Vibration parameters may include amplitude, frequency, ascending and descending slope of the vibration signal and its waveform in general. Modes of vibrations may include sinusoidal, triangular, square-wave, saw-tooth-like signals or a combination of two or more of these modes.
Various types of systems may be used for the vibration generator 124. For example, the vibration generator 124 may include electrodynamic actuators, piezoelectric actuators, pneumatic actuators, hydraulic actuators, and/or mechanical gear systems, although other systems may also be used. Preferably, the frequency of the vibrations may range between 0 to about 100 kHz and the amplitude of the vibrations may range between 0 to about 5 mm. Longitudinal, transverse and/or rotational oscillations may be applied by the vibration generator 124 to the electrode carrier depending on the configuration of the vibration generator 124.
For example,
The floating mass transducer 130 may optionally include one or more springs or dampers 140 positioned between the permanent magnet 136 and either end 132a, 132b of the bushing 132. After the electromagnetic coil 138 has moved the permanent magnet 136 within the inner area 134, the spring(s) 140 may provide a restoring force to the permanent magnet 136 and move the permanent magnet 136 back to a neutral position within the inner area 134. The bushing 132 may be hermetically sealed so as to prevent corrosion and/or leakage of material into or out of the bushing 132. Preferably, the bushing 132 is made of a non-ferromagnetic material and may be made of a biocompatible material, e.g., stainless steel, titanium, aluminum, platinum, nylon and/or a ceramic material.
Although
Another configuration of a vibration generator 124 that may be used is a miniaturized electromotor. For example,
An advantage of positioning the vibration generator 124 within the instrument housing 122 is that the entire vibration unit, including vibration generator 124, power supply 126 and any electronics, is very compact and may be completely detached from the instrument housing 122 for sterilization of the housing 122.
Some embodiments may provide improved methods of inserting the electrode carrier into the cochlea. For example, as shown in
Accordingly, various embodiments of the present invention improve the electrode insertion process by applying vibrations to the electrode carrier. Embodiments should not produce any negative effects on hearing preservation since the motions which are introduced by the vibrations are negligible in comparison to the overall electrode insertion trauma.
Although the above discussion discloses various exemplary embodiments of the invention, it should be apparent that those skilled in the art can make various modifications that will achieve some of the advantages of the invention without departing from the true scope of the invention.
The present application claims priority to U.S. Provisional Patent Application No. 61/220,630 filed Jun. 26, 2009, the disclosure of which is incorporated by reference herein in its entirety.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US10/39988 | 6/25/2010 | WO | 00 | 4/4/2012 |
Number | Date | Country | |
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61220630 | Jun 2009 | US |