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SONATA Surgical Guideline AW7695_5.0 - Med-El

1. Table of contents I Patient selection and evaluation Indication Selection and Evaluation II Technical description of the implant Performance Characteristics Implant Variants III Surgical tools Surgical Kit for the SONATA Cochlear Implant Insertion Test Tools IV General remarks about the surgery V Surgical procedure STEP 1 Prepare Patient STEP 2 Mark Implant Position STEP 3 Plan Incision STEP 4 A Open Skin Flap STEP 4 B Skin Flap Thickness STEP 5 Check Position of Implant and Electrode Lead STEP 6 Drill Mastoidectomy and Posterior Tympanotomy STEP 7 Drill Stimulator Bed and Electrode Channel STEP 8 VARIANT 1 Preparation for a Round Window opening STEP 8 VARIANT 2 Preparation for a Cochleostomy STEP 9 Select Appropriate Electrode Variant STEP 10 Immobilise the Implant STEP 11 Opening the Cochlea STEP 12 Insert the Electrode Array STEP 13 A Seal Cochlear Opening STEP 13 B Secure Electrode Lead STEP 14 Intra operative Recordings STEP 15 Close Wound Appendix MRI Caution X rays Explanting the Device Hearing Preservation Surgical Technique Literature MED EL Surgical Videos MED EL Contacts 14 15 16 16 17 18 19 19 20 21 23 24 26 28 30 31 32 35 36 38 40 41 41 43 43 44 46 50 50 Patient selection and evaluation Patient selection and evaluation Indication The MED EL Cochlear Implant System Is intended to evoke auditory sensations via electrical stimulation
2. Figure 8 Standard Electrode Array Technical description of the implant Medium Electrode Array Order number 04213 The Medium Electrode Array see Figure 9 is 24mm long and designed for cases where deep insertion is not desired or is not possible due to anatomic restrictions It features 12 evenly spaced electrode pairs spaced over 20 9mm with 1 9 mm spacing between each contact pair Note that the Medium Electrode Array is not inserted to the marker ring 24mm Active Stimulation Range ASR 20 9mm 0 _ a 7 amp 0 8mm 0 5mm D 24 platinum electrode contacts Optimal spacing over a 20 9mm stimulation range Diameter at basal end 0 8mm Diameter at apical end 0 5mm Figure 9 Medium Electrode Array 10 Compressed Electrode Array Order number 04211 The Compressed Electrode Array see Figure 10 is 15mm long and designed for partial ossification or malformation of the cochlea It features 12 pairs of contacts spaced closer together in the apical end of the array The contacts are spaced over 12 1mm with 1 1mm between each contact pair Note that the Compressed Electrode Array is not inserted to the marker ring 15mm ASR 12 1mm w Vv 7 N 0 5mm a 0 7mm 24 platinum electrode contacts Optimal spacing over a 12 1mm stimulation range Diameter at basal end 0 7mm Diameter at apical end 0 5mm Figure 10 Compressed Electrode Array Surgical tools
3. III Surgical tools Note that the surgical tools supplied by MED EL should not be modified in any way Modification of any of the tools is done at the surgeon s own risk Detailed instruction of the reprocessing process and the individual preparation before cleaning the tools can be found in the appropriate Instruction for Use Surgical Kit for the SONATA Cochlear Implant The MED EL Surgical Kit is a collection of tools for implantation of the SONATA Cochlear Implant The following tools are included in the SONATA Surgical Kit Implant Template Single Use for the SONATA Order number Shipped with the implant Stimulator Template for the SONATA 04715 Processor Template 01557 Skin Flap Gauge 6 03543 Surgical Claw Angled 00284 Micro Forceps Angled Implant Template Single Use for the SONATA Shipped with the implant This template is used to assess the size and the position of the implant on the skull This tool is delivered in a sterile packaging and is a single use device only 05761 05777 05778 Figure 11 Implant Template Single Use for the SONATA 11 Surgical tools Stimulator Template for the SONATA Order number 04715 This template is used to outline the position of the stimulator on the skull and to assess the size and flatness of the stimulator bed It features a detachable handle that should always be used in order to ensure correct positioning This tool is a re usab
4. withstand these exerting forces e Patients with mechanically damaged implants must not undergo MRI Ignoring this guideline could result in injury to the patient Safety Guidelines e Before patients enter any MRI room all external components of the implant system audio processor and accessories must be removed For field strengths of 1 0 T or 1 5 T a supportive head bandage must be placed over the implant A supportive head bandage may be an elastic bandage wrapped tightly around the head at least three times refer to Figure 56 The bandage shall fit tightly but should not cause pain Head orientation In case of 1 0 T and 1 5 T systems the longitudinal axis of the head must be parallel to the main magnetic field of the scanner For example this is the case when the patient is in a supine position with the head kept straight The patient should not turn or bend his her head to the side otherwise partial demagnetization of the implant magnet is possible In case of 0 2 T scanners no specific head orientation is required Sequences in Normal Operating Mode shall be used only During the scan patients might perceive auditory sensations such as clicking or beeping Adequate counseling of the patient is advised prior to performing the MRI The likelihood and intensity of auditory sensations can be reduced by selecting sequences with lower specific absorption rate SAR and slower gradient slew rates Figure 56 H
5. 4mm Markers 2x5 Max insertion depth 18 0 mm 16 Insertion Electrode IE With the Insertion Electrode IE the surgeon can establish whether the cochlear lumen is obstructed or if it is freely accessible up to different insertion depths depending upon the considered electrode variant planned for the implantation The Insertion Electrodes are delivered in sterile packaging and are single use devices only Order Number Electrode Array 08255 FLEXSOFT 08348 FLEX28 08257 FLEX24 08254 Standard 08256 Medium 08258 Compressed General remarks about the surgery IV General remarks about the surgery Prophylactic use of antibiotics is recommended for all patients unless medically contraindicated Facial nerve monitoring is recommended When carried out neuromuscular blockage should be avoided Evaluation of possible electrode insertion length for the individual patient should be done prior to the surgery This can be performed by a standard X ray or a CT scan Sterility of the implant must De ensured at all times The implant must never be dropped onto a hard surface damage to the implant or electrodes during the operation will invalidate the warranty Before opening the implant box a telemetry should be done to check the function of the implant inside the Dox In cases where the patient has a thick skin flap the flap should be thinned to no more than 6mm Use the Skin Flap Gauge 6 to accurately determine
6. a micro forceps should be used e g Hartmann Alligator Forceps 8 mm After fixing the bone fixation clip the electrode fixation clip Shall be closed over the electrode lead so that both ends of the electrode fixation clip come together and the clip is completely closed see Figure 54 The electrode lead is longer than required in order to accommodate anatomical variants and to compensate for Skull growth in children The electrode lead is looped in the mastoid cavity well below the surface of the bone using the cortical overhang to hold it in place to avoid postoperative movements due to contractions of the temporalis muscle see Figure 55 Additional immobilisation of the electrode lead inside the electrode channel could be done e g with bone pate or bone wax Figure 52 Placement of the Fixation Clip on the bony bridge Figure 53 Bone fixation clip crimped on the bony bridge Figure 54 Electrode fixation clip closed over the electrode Figure 55 The electrode lead should be loosely placed under the cortical overhang right ear 39 Surgical procedure STEP 14 Intra operative Recordings At this stage intra operative recordings like Impedance Field Telemetry IFT Electrically Evoked Stapedius Reflex Threshold ESRT Electrically Evoked Brainstem Response EABR or Auditory Nerve Response Telemetry ART can be performed Intra operative measurements are performed with the appropriate M
7. medical grade stainless steel The device Is delivered non sterile Micro Forceps Angled Order number 05761 Right Angled amp Left Angled 05777 Right Angled 05778 Left Angled The Micro Forceps Left Angled and the Micro Forceps Right Angled are used to grip hold and insert the electrode into the cochlea without damaging it It is the surgeon s preference which angled Micro Forceps to use to insert the electrode array in either the left or the right ear In the closed position the tips of the forceps are parallel to each other separated by a distance of 0 25mm This tool is a re usable surgical instrument made from medical grade stainless steel The device is delivered non Sterile Figure 15 Surgical Claw Angled Figure 16 Micro Forceps Right Angled Micro Forceps Left Angled 13 Surgical tools The following tools are additions to the surgical kit and may be ordered separately FENTEXmedical Forceps FENTEXmedical GmbH is specialized in the development manufacturing and marketing of surgical instruments and visualization systems for ENT Head amp Neck and Facial Surgery Basic description of the device Cl Electrode Insertion Forceps L 155 mm with longitudinal groove for electrodes with a basal diameter in the range 0 8 13 mm FENTEXmedical forceps have been successfully tested at headquarters with all MED EL electrode arrays This surgical tool is no MED EL product and may therefore be ordered directl
8. of the auditory pathways It is designed for severely to profoundly hearing impaired individuals who obtain little or no benefit from acoustic amplification in the best aided condition Additionally the MED EL Cochlear Implant System used in combination with the implant variant FLEX24 and FLEX20 is intended to evoke auditory sensations via electrical stimulation or via combined electric acoustic stimulation EAS of the auditory pathways for partially deaf individuals who obtain benefit from acoustic amplification in the lower frequencies only The MED EL Cochlear Implant System is also intended to evoke auditory sensations via electrical stimulation of the auditory pathways for individuals with single sided deafness which is defined as severe to profound hearing impairment in one ear and normal hearing or mild to moderate hearing impairment in the other ear Selection and Evaluation Patients should fulfil the audiological criteria of their respective country for open set sentence testing and open set monosyllabic words when tested with hearing aids MED EL strongly recommends the use of optimally fitted hearing aids for a minimum of three months before deciding to pursue a cochlear implant In cases of ossification or deafness due to infectious disease there may be no need to try a hearing aid and implantation should generally not be delayed A complete cochlear implant evaluation protocol should include an audiologic assessme
9. skin flap thickness The implant must be securely anchored in the stimulator bed drilled in the temporal bone The electrode lead should be placed in a ramp like bony channel without sharp edges to protect it against postoperative movement and excessive mechanical impact Do not place sutures over the active electrode lead Only surgical instruments approved by MED EL should be used during the insertion process other instruments probes hooks forceps tweezers etc can damage the electrode array The electrode array should be inserted as far as possible or planned according to the individual electrode insertion length into the cochlea without compressing the array or using excessive force After the electrode array has been inserted into the cochlea small pieces of temporalis fascia should be placed around the electrode array at the entrance to the cochlea to secure the electrode array and to seal the cochlea opening The excess electrode lead must be looped and secured with caution in the mastoid cavity It must be secured under the cortical overhang so that the electrode array will not migrate out of the cochlea or be subject to external pressure that could cause movement and subsequent damage to the electrical connections Monopolar electrosurgical instruments must not be used in the head and neck region If bipolar electrosurgical instruments must be used the tips of the cautery must be kept at least 3 cm away from the stimu
10. the dura may reduce the barrier to future infection and may increase the potential risk for future meningitis For example neuro radiological follow up in cases of fractures of the anterior skull base have shown that foudroyantly progressing meningitis may occur even years later Similar mechanisms may also exist in respect of ear and mastoid surgery Facial nerve monitoring is recommended when carried out neuromuscular blockade should be avoided A standard cortical mastoidectomy is performed with a cutting Durr while ensuring good irrigation A cortical overhang should be left both superiorly and posteriorly it can later serve as a natural support for the electrode lead as It is looped in the mastoid cavity The fossa incudis should be located and the tip of the short process of the incus is identified to ensure the proper orientation of the posterior tympanotomy This important part of the operation should be practiced many times on human cadaver temporal bones before live surgery is performed A triangular opening is made between the mastoid and the facial nerve which is referred to as the facial recess The posterior limit is the vertical portion of the facial nerve the anterior limits are the anulus and chorda tympani and the upper aspect is a bony buttress at the level of the fossa incudis Start drilling immediately below the fossa incudis using a 3mm diamond burr centered on the tip of the short process Use high magn
11. 005 Appendix Insertion depth differences in bilateral cochlear implantees Fielden C Long C Cooper H Proops D Donaldson Craddock L Cochlear Implants Int 6 Supp 1 2005 Sep The following is a list of references on HP and EAS Hearing preservation after cochlear reimplantation Helbig S Rajan GP Stover T Lockley M Kuthubutheen J Green KM Otol Neurotol 34 1 2013 Jan p 61 65 The Round Window Is it the Cochleostomy of Choice Experience in 130 Consecutive Cochlear Implants Gudis DA Montes M Bigelow DC Ruckenstein M Otol Neurotol 2012 Sep 11 Evaluation of round window accessibility to cochlear implant insertion Leong AC Jiang D Agger A Fitzgerald O Connor A Eur Arch Otorhinolaryngol 2012 Jul 18 Hearing preservation after cochlear implantation using deeply inserted flex atraumatic electrode arrays Tamir S Ferrary E Borel S Sterkers O Bozorg Grayeli A Audiol Neurootol 2012 17 5 331 7 Hearing preservation and hearing improvement after reimplantation of pediatric and adult patients with partial deafness a retrospective case series review Jayawardena J Kuthubutheen J Rajan G Otol Neurotol 2012 Jul 33 5 740 4 Scalar localization by computed tomography of cochlear implant electrode carriers designed for deep insertion Helbig S Mack M Schell B Bratzke H St ver T Helbig M Otol Neurotol 2012 Jul 33 5 745 50 A case series of paediatric hearing preservation cochlear im
12. Cochlear Implants VI D I Fl SONATATI Surgical Guideline L ke AW7695_5 0 English EU Introduction The MED EL Cochlear Implant System serves to restore hearing sensations through electrical stimulation of the auditory nerve It is the result of many years of research at leading technical institutions throughout the world MED EL cochlear implants are manufactured to the highest quality standards in order to ensure long term reliability All materials used in the implant have been rigorously tested for biocompatibility durability and reliability MED EL applies a quality management system that meets all EN ISO 13485 2003 requirements and complies with US Quality System Regulations and Canadian Medical Device regulations CAN CSA ISO 13485 2003 Components of the MED EL Cochlear Implant System meet the requirements for AIMD 90 385 EEC and MDD 93 42 EEC This Surgical Guideline describes proper techniques for implanting the SONATATI Cochlear Implant hereafter referred to as the SONATA It serves as additional information for professionals and should not be used as an Instructions oee The information in this brochure is believed to be true and correct However specifications are subject to change without notice Not all products represented on these materials are currently approved or available in all markets For country specific information please see the applicable Instruction for Use delivered with the implant system
13. ED EL application software and the MED EL hardware interface system For details please refer to the applicable Software User Manual It is not possible to sterilise any component of the MED EL hardware interface system When used in a sterile environment the coil and cable should be covered with sterile material i e sterile sleeve The appropriate coil should be used during intra operative recordings Since the coil should not be placed directly on the implant either sterile gauze drenched in saline solution or the skin flap should be placed between the coil and the implant Moistening the underside of the skin flap with sterile saline or pooling saline over the ground electrode of the implant prior to performing intra operative recordings may improve readings 40 IFT Impedance Field Telemetry After the implant is in place a telemetry check allows e individual electrode impedance measurements e verification of the absence of short and open circuits between electrodes e determination of intra cochlear voltage distribution As with any telemetry system intra operative impedance testing may not provide an accurate representation of later electrode function High values observed intra operatively may be caused by air bubbles on the electrode contact surface These generally dissipate within a few hours or days after surgery ESRT Electrical Stapedius Reflex Threshold If ESRT thresholds are measured care should b
14. anotomy to get a clear view onto the RW niche Before starting the preparation of the RW niche a mucosal fold should be removed from the promontory This prevents mucosal bleeding and provides better feedback from the tip of the drill see Figure 33 To facilitate the electrode insertion a portion of the anterior inferior bony RW margin as well as the superior overhang of the RW niche needs to be drilled away This increases the accessibility of the RW and prevents the electrode from being directed towards the modiolus One potential risk associated with drilling the RW margin relates to its close proximity to the opening of the cochlear aqueduct Care should be taken to avoid this inner ear structure Advantages of a RW opening e The amount of drilling is significantly reduced compared to a cochleostomy and no endosteal preparations in the direct vicinity of the basilar membrane are needed e The round window always leads into the correct scala for an electrode insertion the scala tympani 26 Figure 33 Elevating a mucosal flap right ear Surgical procedure To enter the middle portion of the scala tympani and to get visualisation of the RW membrane the posterior superior lip of the round window niche and the inferior margin of the round window should be drilled away By doing this the round window will be exposed for best insertion of the electrode array see Figure 34 The RW niche is drilled and exposure should
15. be extensive enough to comfortably fit the electrode An appropriate RW opening in relation to size is dependent upon the type of electrode array chosen Please refer to STEP 9 Select Appropriate Electrode Variant e Begin drilling near the cochlea use a slow turning diamond drill to avoid acoustic trauma e To enter the middle portion of the scala tympani and to get visualisation of the round window membrane the posterior superior lip of the round window niche and the inferior margin of the round window should be drilled away to expose the round window membrane at least 0 8mm e Fill the electrode insertion site with corticosteroid e Protect the middle ear cavity from bone dust contamination by closing it with medical gauze Scala vestibuli RW ee e o e ee Er APR Seaarymen gt IR P a 609 aa e eo o Figure 34 RW niche anatomy 27 Surgical procedure STEP 8 VARIANT 2 Preparation for a Cochleostomy CAUTION BEN e For drilling the cochleostomy always use a slowly turning diamond drill to avoid acoustic trauma approx 1000rpm e Try to keep the endosteum intact until the insertion of the electrode Before preparing to drill the cochleostomy the mucosal fold should be removed over the promontory This prevents mucosal bleeding and provides better feedback from the tip of the drill see Figure 36 The round window niche is identified and the c
16. by closing it with medical gauze Figure 37 Drilling the cochleostomy and leaving the endosteum intact when drilling upper picture smoothing the edges of the cochleostomy lower picture 29 Surgical procedure STEP 9 Select Appropriate Electrode Variant Complete Cochlear Coverage CCC means stimulating the cochlea from the base to the apical region in order to stimulate a maximum number of nerve fibres Stimulation of the entire frequency range with a deeply inserted long array provides the implant user with the best possible outcomes in speech performance measures and in sound quality MED EL Cochlear Implants are available with several different electrode options For hearing preservation with especially atraumatic electrode arrays or for even the most difficult cases of cochlear ossification obstructions or malformations see Figure 38 Reduced Cochlear Duct Length or Malformations Depending on the cochlear duct length or the malformation of the cochlea a FORM24 FORM19 FLEX24 FLEX20 Medium or Compressed Electrode Array may be appropriate for optimal cochlear coverage and stimulation Cochlear Ossifications The surgeon must be prepared for unexpected findings during surgery Depending on the degree of ossification different surgical approaches and Electrode Arrays can be used Partial Ossification If only the inferior section of the basal coil is ossified drilling along the basal turn can ofte
17. dix Round Window Insertion Cochleostomy Insertion Using a micro lancette or micro hook carefully incise the With a micro lancette or micro hook carefully incise round window membrane in its inferior anterior quadrant the endosteum to approximately 0 8 mm to approximately 0 8 mm Avoid suctioning in the open region of the cochlea Immediately start the electrode insertion through the drop of corticosteroid and hyaluronic acid General insertion direction is from superior posterior to anterior inferior with the knob indicating the direction of the apical electrodes facing towards the modiolus Active Stimulation Range 20 9mm w y V Zr nn FLEX tip 2 0 8mm 24mm 19 platinum electrode contacts Optimal spacing over a 20 9mm stimulation range amp Flex tip for minimal insertion trauma Dimensions at apical end 0 5 x 0 3mm 3 Diameter at basal end 0 8mm Insert the FLEX24 electrode so that it covers less than 1 5 turns of the cochlea 22 24mm determined by pre operative CT scan To seal the cochlea use a small fascial graft To prevent contamination of the electrode and to increase flexibility rinse the fascial graft with saline solution A course of steroids and antibiotics should be given postoperatively Figure 60 Hearing Preservation Surgical Technique Part 2 Appendix Literature The following is a list of references on general Cl surgery The Effects
18. e length of the organ of Corti in man Hardy M American Journal of Anatomy 62 2 1938 179 311 The following is a list of references on bilateral Cl surgery Assessment of electrode placement and audiological outcomes in bilateral cochlear implantation Wanna GB Noble JH McRackan TR Dawant BM Dietrich MS Watkins LD Rivas A Schuman TA Labadie RF Otol Neurotol 2011 Apr Binaural cochlear implantation after bilateral temporal bone fractures Zanetti D Campovecchi CB Pasini S Int J Audiol 2010 Jul 8 Bilateral cochlear implantation in a patient with bilateral temporal bone fractures Chung JH Shin MC Min HJ Park CW Lee SH Am J Otolaryngol 2010 May 3 Bilateral cochlear implantation in children with anomalous cochleovestibular anatomy Chadha NK James AL Gordon KA Blaser S Papsin BC Arch Otolaryngol Head Neck Surg 135 9 2009 Sep Bilateral simultaneous cochlear implantation in children surgical considerations Migirov L amp Kronenberg J Laryngol Otol 2009 Mar 3 1 3 Otopathological Findings in a Patients with Bilateral Cochlear Implants House W Johnsson L amp Linthicum F USPHS Research 74 2006 Cochlear implantation in a patient with bilateral temporal bone fractures Simons J Whitaker M amp Hirsch B Otolaryngol Head Neck Surg 132 809 811 2005 Bilateral cochlear implantation Lustig L amp Wackym P Operative Techniques in Otolaryngology 16 2
19. e taken that no muscle relaxant Is used during the last half hour before performing the measurements Note that observation of the reflex is not possible in some implanted patients due to various physiological and anatomical reasons In addition observation of the reflex may not be possible due to anaesthesia Therefore absence of a reflex should not be taken as an indication of implant malfunction or lack of auditory response without other more direct evidence Intra operatively the presence of the reflex can be monitored either by direct observation of the ipsilateral tendon through the microscope or by impedance probe measurements in the contralateral ear Direct observation is employed in most cases as this is normally straightforward and does not require additional equipment Probe measurements are usually restricted to research studies Surgical procedure EABR Electrically Evoked Brainstem Response With the addition of the EABR task it is possible to measure and record the response of the entire auditory pathway to stimulation from the implant EABR recordings can be used to determine the best placement of an Auditory Brainstem Implant during surgery and they can also provide interesting information on the function of the whole auditory pathway The MED EL application software EABR parameters can be adjusted to facilitate recording of early middle and late electrical potentials To obtain measurements with the EABR
20. ead bandage to support fixation of the implant 43 Appendix 44 Image artifacts are to be expected refer to Figure 57 The above instructions should also be followed if areas of the body other than the head are to be examined e g knee etc When lower extremities are to be examined it is recommended that the patient s legs are positioned in the scanner first to minimize any risk of weakening the implant magnet e The above instructions also apply for patients with bilateral cochlear implants or Dilateral auditory brainstem implants If the conditions for MR safety and the Safety Guidelines are not followed injury to the patient and or damage to the implant may result Figure 57 MR images obtained with a 1 5 T scanner 8 year old child Appendix X rays The SONATA Cochlear Implant can be identified by x ray post surgery Right is an example for the device Explanting the Device e The implant may become non functional either by accident or due to medical or technical reasons In this case It is strongly recommended to replace the device e If for any reason the device is not used anymore it is strongly recommended to explant the device If an explantation is not performed functional checks of the Figure 58 X ray of SONATA implant on a regular basis are strongly recommended e If possible the device should be removed without damaging or cutting it Damage to the device during or after explantation
21. edicine 5 4 2007 p 218 223 Complications in children with long term cochlear implants Lin Y Lee F Peng S ORL J Otorhinolaryngol Relat Spec 68 4 2006 p 237 242 Cochlear implantation in children younger than 12 months of age Wackym P Firszt J Runge Samuelson CG Operative Techniques in Otolaryngology 16 2005 p 101 106 Cochlear implantation in deaf infants Miyamoto R Houston D Bergeson T Laryngoscope 115 2005 p 1376 1380 Cochlear implantation at under 12 months Report on 10 patients Colletti V Carner M Miorelli V Guida M Colletti L Fiorino F Laryngoscope 115 2005 p 445 449 Appendix The following is a list of references on alternative approaches VERIA TECHNIQUE Veria operation Updated Kiratzidis T Arnold W lliades T ORL 64 406 412 2002 Veria operation Kiratzidis T Iliades T Arnold W ORL 64 413 416 2002 Veria operation Cochlear implantation without a mastoidectomy and a posterior tympanotomy Kiratzidis T Adv Otorhinolaryngol 57 127 130 2000 SUPRAMEATAL APPROACH How we do it The suprameatal approach An alternative surgical technique for cochlear implantation Kronenberg J Migirov L Cochlear Implants International 7 142 147 2006 The Suprameatal Approach An alternative surgical approach to cochlear implantation Kronenberg J Baumgartner W Migirov L Dagan T Hildesheimer M Otol Neurotol 25 41 45 2004 The role of Mastoidectomy in cochlear implant surg
22. efault factory settings of the implant system e Proper functioning of the implantable part of the CI system can be checked by performing telemetry refer to MAESTRO application software User Manual e The implant has 24 independent current sources stimulating 12 independent electrode channels in monopolar mode e The implant has a mass of 8 6g typical value e The volume of the implant without electrode is 4 2 cm e The electrode is made of medical grade silicone platinum electrode contacts and platinum iridium 90 10 wires and nitinol e All electrode variants have a straight and flexible design The electrode does not deliver any medicinal substances e Geometric surface area of the stimulation reference electrode 50mm7 e Following materials are in direct contact with human tissue medical grade silicone platinum iridium Implant variants availability is subject to regulatory approval Implant Variants Cochleae may differ significantly in size and shape from One another as can individual cochlear duct lengths MED EL offers the largest selection of electrode arrays for each implant variant Please see Section V Step 9 Select Appropriate electrode Variant for the circumstances in which each variant should be used FLEXSOFT Electrode Array Order number 04215 The FLEXSOFT Electrode Array see Figure 2 is 31 5mm long featuring FLEX tip technology for increased mechanical flexibility and enabling CCC Com
23. er 14 3 mm with 1 3 mm spacing between each contact pair The FORM19 electrode array features an integrated SEAL function designed to close off the cochlear opening SEAL is a 2 4 mm conical thickening located at the basal end of the array designed to control the leakage of cerebrospinal fluid CSF also known as gusher 19mm ee ASR 14 3 4 3mm w H i u a a MIN amp 0 8mm 0 5mm CSF SEAL 24 platinum electrode contacts Optimal spacing over a 14 3mm stimulation range Diameter at basal end 0 8mm CSF SEAL Diameter at apical end 0 5mm Figure 7 FORM 19TM Standard Electrode Array Order number 04210 The Standard Electrode Array see Figure 8 is 31 5 mm long and designed for long cochlear duct lengths Contacts are spaced over 26 4mm with 2 4mm spacing between each contact pair The electrode s length allows insertion into the scala tympani and stimulation of the cochlear canal to the fullest extent possible The array features a marker ring 31 5 mm from the apex that is used to seal and to indicate maximum electrode insertion The diameter of the array increases to 1 3mm at the proximal thicker part of the array Just before the marker ring 31 5mm Active Stimulation Range ASR 26 4mm 9 w EIEE B 1 3mm 0 5mm 24 platinum electrode contacts Optimal spacing over a 26 4mm stimulation range Diameter at basal end 1 3mm Diameter at apical end 0 5mm
24. ery Kronenberg J Migirov L Acta Otolaryngol 123 219 222 2003 The suprameatal approach in cochlear implant surgery Our experience with 80 patients Kronenberg J Migirov L Baumgartner W ORL 64 403 405 2002 Suprameatal approach New surgical approach for cochlear implantation Kronenberg J Migirov L Dagan T J Laryngol Otol 115 283 285 2001 PERI CANAL TECHNIQUE Cochlear implantation without mastoidectomy The pericanal electrode insertion technique Hausler R Acta Oto Laryngologica 122 715 719 2002 ATTICOTOMY APPROACH Transepitympanic Approach in Cochlear Implantation Nahler A Boheim K 5th European Congress of Oto Rhino Laryngology Head and Neck Surgery Rodos Kos Hellas 2004 Poster Kombinierter Epitympanaler Transmeataler Zugang bel Cochleaimplantation Nahler A B heim K 47 sterreichischer HNO Kongre 2003 in German Transatical Approach Modifications C zar Fragola Calder n Revilla Gonzalez de Ubieta Poster presentation Las Palmas 2002 Poster Arauz http www implantescocleares com in Spanish with video 51 Appendix MED EL Surgical Videos Please contact you local MED EL office or distributor for the latest MED EL Surgical Videos or visit the MED EL Professional Webpage www medel com professionals MED EL Contacts For MED EL Contacts please visit the MED EL Webpage www medel com contact offices 52 MED EL Elektromedizinische Gerate GmbH Headquarter
25. f the electrode ina recessed channel This ensures that the reinforced part of the electrode lead does not protrude into the mastoidectomy Once the implant template is in place surgical ink may be used to mark its position on the surface of the skin Surgeons may choose to transpose the position of the implant template onto the surface of the bone by using a hypodermic needle inserted perpendicularly to the skin at points along the side of the implant template When implanting a patient bilateral care should be taken of the placement of the implants In particular the second side should be placed specifically to match the location of the first to give symmetric appearance of the external part The skull curvature and pinna position needs to be taken into consideration when placing the second implant similar Figure 22 Suggested orientation of the templates to the contralateral side right side 19 Surgical procedure STEP 3 Plan Incision Choose the line of incision so that a well vascularised skin flap results Make the incision 1 2 cm from the implant to ensure that the scar will not lie directly over the body of the implant Incise the tissue with a scalpel and use bipolar electrocoagulation for hemostasis An example of a commonly used postaural incision is shown in Figure 23 and Figure 24 Postaural incisions start in the Sulcus behind the pinna and extend posteriorly For greater mastoid bone exposure each of these i
26. force The marker ring is located 28mm from the electrode tip and indicates the deepest Insertion Near the marker ring the electrode lead features an additional marker dot on the same side of the array as the single apical contacts The marker allows the surgeon to ensure appropriate alignment of the single contacts toward the modiolus 28mm Active Stimulation Range 23 1mm pi v eosin 0 5 x j mm FLEX Tip 19 platinum electrode contacts Optimal spacing over a 23 1mm stimulation range Diameter at basal end 0 8mm FLEX Tip for minimal insertion trauma Dimensions at apical end 0 5 x 0 4mm Figure 3 FLEX28 Electrode Array FLEX24 Electrode Array Order number 04214 The FLEX24 Electrode Array see Figure 4 is 24mm long featuring FLEX tip technology and designed for combined Electric Acoustic Stimulation EAS less than 1 5 turns The contacts for the 12 channels are arranged as 5 single contacts at the apical array end and 7 contact pairs at the base with a 1 9mm spacing between each channel The specially designed electrode tip offers increased mechanical flexibility for reduced insertion force The marker ring is located 24mm from the electrode tip and indicates the deepest insertion Near the marker ring the electrode lead features an additional marker dot on the same side of the array as the single apical contacts The marker allows the surgeon to ensure appropriate alignment of the single contac
27. g with the marker ring should not be achieved with the Medium and Compressed Electrode Arrays When the electrode array is fully inserted the marker ring will seal the cochlear opening providing an additional point of fixation see Figure 48 This sealing will only take place with the FORM24 FORM19 FLEXSOFT FLEX28 FLEX24 FLEX20 and Standard Electrode Array fully inserted For all MED EL Electrode Arrays small pieces of temporalis fascia placed around the electrode array at the entrance to the cochlea should be used to secure the electrode array and to seal the opening Rinse the small pieces with saline solution to prevent contamination of the electrode and to increase flexibility e To seal the cochlea use a small fascial graft To prevent contamination of the electrode and to increase flexibility rinse the fascial graft with saline solution Figure 48 The electrode lead should be loosely placed under the cortical overhang right ear 32 Surgical procedure STEP 13 B Secure Electrode Lead If you choose to secure the electrode lead in the posterior tympanotomy fibrin glue or bone pate can be used MED EL offers a Fixation Clip to secure the electrode lead to the bony bridge incus bridge Securing the electrode lead with the Fixation Clip Order number 09917 CAUTION SS e The Fixation Clip shall not be used in the case that the bony bridge is not suitable for placing the Fixation Clip e T
28. gnal transmission the skin flap or the muscle may need to be thinned out so it does not exceed 6mm Evaluate the portion of the flap over the magnet and receiving coil with the Skin Flap Gauge 6 as shown in Figure 26 If the flap does not fit in the gauge loosely carefully thin the flap until it does It is important to avoid over thinning of the flap which may result in wound complications Care must be taken to avoid exposing hair follicles Figure 25 Double layer skin flap right ear Figure 26 Using the Skin Flap Gauge 6 right ear 21 Surgical procedure STEP 5 Check Position of Implant and Electrode Lead CAUTION REEEEEN Retractors may distort the actual position of the implant in relation to the pinna as the ear is retracted The SONATA Implant Template should be placed on the skull in order to visually check its proper position The bony ear canal should be identified and re marking on the skull should be done if necessary see Figure 27 22 Sas rm N S 7 1 7 1 Figure 27 Marking the implant position with the Implant Template right ear Surgical procedure STEP 6 Drill Mastoidectomy and Posterior Tympanotomy CAUTION BEE Clear identification of the anatomical landmarks is required When drilling care should be taken to avoid exposing the dura inadvertently If the dura is exposed as a landmark exposure Shall be kept to an absolute minimum Inadequate large exposure or injury to
29. h Frequency Hearing Loss Clinical Experience Arnoldner G Helbig S Wagenblast J Baumgartner WD Hamzavi JS Riss D Gstoettner W Adv Otorhinolaryngol 67 2010 49 Appendix Partial deafness cochlear implantation at the university of kansas techniques and outcomes Prentiss S Sykes K Staecker HJ Am Acad Audiol 21 3 2010 Preliminary Results of Electric and Acoustic Stimulation Using the MED EL Sonata Flex EAS Electrode Array Walker A Mawman D Brough J O Driscoll M Ramsden R Green K Freeman S Cochlear Implants Int 11 Suppl 2 2010 Electric Acoustic Stimulation EAS of the Auditory System Experience and Results of Ten Patients Using MED EL s M and Flex Electrodes Lee A Jiang D McLaren S Nunn T Demler J Tysome J Connor S Fitzgerald O Connor A Clinical Otolaryngology 2010 Results of partial deafness cochlear implantation using various electrode designs Skarzynski H Lorens A Piotrowska A Podskarbi Fayette R Audiol Neurootol 14 Suppl 1 2009 Preservation of low frequency hearing in partial deafness cochlear implantation PDCI using the round window surgical approach Skarzynski H Lorens A Piotrowska A Anderson I Acta Otolaryngol 2007 127 1 41 8 Outcomes in adults implanted with the FLEX electrode Baumgartner W Jappel A Morera Perez C Gstottner W Muller J Kiefer J Van De Heyning P Anderson l Bryde Nielsen S Acta Otolaryngol 127 579 2007 Method for hearing
30. he recommended size of the bony bridge is 2 mm e Accidental bending of the Fixation Clip during removal from its packaging must be avoided in order to prevent functional damage e Care should be taken that during the fixation of the bone fixation clip the Incudostapedial joint is not harmed and the movements of the ossicles are not inhibited e Care should be taken not to squeeze or damage the electrode The Fixation Clip shall be used exclusively with MED EL electrodes that have a diameter of 1 3 mm at the distal part of the electrode lead see Figure 49 The openings are not of the same size The larger opening of the Fixation Clip is the Done fixation clip and the smaller opening of the Fixation Clip is the electrode fixation clip see Figure 51 Figure 49 Fixation Clip MsO10103 Electrode array Distal part of the electrode lead Figure 50 Distal part of the electrode lead Electrode fixation clip Bone fixation clip lmm LLS ini as Figure 51 Dimensions of the Fixation Clip Fixation Clip development was in close collaboration with Prof Joachim Muller Klinik und Poliklinik fur Hals Nasen und Ohrenheilkunde Munchen Gro hadern Germany 38 Surgical procedure First the larger clip bone fixation clip shall be placed on the bony bridge see Figure 52 Next the bone fixation clip shall be properly crimped to the bony bridge see Figure 53 For crimping the Fixation Clip
31. heir physician whether vaccination may be appropriate for them The immunisation status of all cochlear implant candidates should be determined prior to surgery Vaccination may reduce the risk of infection Technical description of the implant II Technical description of the implant The SONATA is the implantable part of the MED EL Cochlear Implant System and can only be used together with compatible MED EL external components The device consists of a stimulator a coil with a magnet within its centre a reference electrode an EAP reference electrode and an active electrode permanently attached to the stimulator The active electrode can be of different types thus resulting in different implant variants implant family SONATA This device is intended to be implanted by adequately trained and experienced surgeons only The SONATA has been designed according to the highest safety and reliability standards All materials used in the construction of the SONATA have been extensively tested for Diological compatibility and durability The power required by the implant is transmitted from the external audio processor through the intact skin via an inductive link The implant therefore contains no batteries or other components that require replacement The implant offers a stimulation mode and a telemetry mode Stimulation sequences of biphasic and triphasic pulses can be delivered sequentially or simultaneously on two or more channels In
32. ification and copious irrigation Extreme care should be taken in drilling the posterior tympanotomy and the surgeon should be aware of any possible anatomical variants of the facial nerve aola3aNl POSTERIOR Figure 28 Anterior and posterior tympanotomy right ear 23 Surgical procedure The following should be visible after the posterior tympanotomy the long process of the incus the incudostapedial joint the stapes pyramid and stapedius tendon the promontory and the round window niche see Figure 29 and Figure 30 When the Fixation Clip is used to stabilize the electrode lead inside the middle ear cavity care should be taken that the bony bridge see Figure 29 is created according to the dimensions of the Fixation Clip The recommended size of the bony bridge is 2mm It is recommended to create a larger posterior tympanotomy as compared to that of a standard cochlear implantation beside the anterior tympanotomy in order to provide a better view as well as more space to manoeuvre the electrode array e Elevate a mucosal flap to avoid mucosal bleeding when opening the cochlea Double layer skin flap see Figure 30 The four different tissue layers skin subcutis muscle and periosteum are incised with two different incisions First the skin subcutis and muscle are raised and retracted Second the periosteum is incised the periosteum is freed from the surface of the bone and then
33. inject local anaesthetics containing vasoconstrictors e g adrenaline 1 200 000 up to 20 mls 18 e Please ensure that corticosteroids crystalline triamcinolone solution or dexamethasone Intravenous corticosteroids and hyaluronic acid are all available for the surgery E Administer intravenous antibiotics from the Cephalosporin group approximately half an hour before the skin Incision Surgical procedure STEP 2 Mark Implant Position Place the Processor Template behind the ear and position the Implant Template or the Implant Template Single Use for the SONATA There are various orientation options A suggested orientation for each ear is shown in Figure 21 and Figure 22 but the orientation depends on various factors like e g the curvature of the skull Position the implant template in such a way that the SONATA Cochlear Implant will be in the hair bearing area The lower part of the stimulator should be under or close to the temporal line with an angle between 30 and 60 The electrode exits on the lateral side of the implant Therefore the electrode lead comes out superiorly for the left ear and inferiorly for the right ear Particular attention should be paid to the placement of the electrode lead on the skull The position of the reinforced Figure 21 Suggested orientation of the templates part of the electrode lead should be selected to facilitate left side the placement of the entire length o
34. lator coil and all areas of the electrode A paper on pathomechanisms clinical symptoms conservative and surgical treatments in cases of meningitis may be useful additional reading Arnold et al ORL 2002 64 382 389 17 Surgical procedure V Surgical procedure The SONATA Cochlear Implant can be implanted using a Small incision however for demonstration purposes only the following illustrations include an enlarged incision area Additionally some of the medical illustrations are schematic and can differ from a patient s anatomical situation Every Cl surgery should be performed as atraumatically as possible so that residual hearing can be preserved The following surgical procedure will ensure that Additional important surgical steps for EAS patients can De found in the appropriate EAS Infobox Summarised EAS information can be found in the appendix STEP 1 Prepare Patient As a prophylactic measure Intravenous antibiotics should be given 1 2 to 1 hour before the incision is made After the patient has been anaesthetised the incision area should be shaved Usually an area including the incision line and the area between the incision and the pinna Is shaved Some surgeons choose to shave only the area over the predetermined line of the incision and they recommend a margin of at least 2cm around the incision Meticulous care should be taken to ensure that the site is well cleansed After cleansing and draping the site
35. le surgical instrument made from medical grade stainless steel The device is delivered non sterile Processor Template Order number 01557 The Processor Template TEMPO OPUS template shows the minimum spacing which must remain free behind the ear so that the external coil and the BTE Audio Processor do not interfere with each other when worn by the patient post operatively This tool is a re usable surgical instrument for transient use made from medical grade stainless steel The device is delivered non sterile Skin Flap Gauge 6 Order number 03543 The Skin Flap Gauge 6 is used to evaluate the thickness of the skin flap in the area covering the cochlear implant A skin flap thickness of 6mm or less is necessary for a good magnetic hold and optimal signal transmission Thick skin flaps should be reduced to 6mm or less This tool is a re usable surgical instrument for transient use made from medical grade stainless steel The device is delivered non sterile 12 Figure 12 Stimulator Template for the SONATA Figure 13 Processor Template TEMPO OPUS Template Figure 14 Skin Flap Gauge 6 Surgical tools Surgical Claw Angled Order number 00284 The Surgical Claw Angled can help to position and insert the electrode array into the cochlea The tip of this instrument is slightly bent for better visualization during electrode insertion This tool is a re usable surgical instrument for transient use made from
36. may prevent or reduce the manufacturer s ability to determine the root cause of failure e Staff should follow common universal precautions and handle the explanted device as potentially contaminated biohazardous material e After explantation the implant should be appropriately cleaned and disinfected During cleaning extraneous tissue should be removed but only to such an extent that damage to the implant is not risked e An explanted device should be placed in a leak proof disinfected or sterile container filled with saline and returned to MED EL Headquarters The device should be accompanied by written information including the reason for explantation Appendix Hearing Preservation Surgical Technique A special marked paragraph can be found in each Surgical Step showing details which are important for Hearing Preservation for an EAS surgery A summary on the additional EAS related surgical steps can be found in Figure 59 Round Window Insertion Cochleostomy Insertion Please ensure that corticosteroids crystalline triamcinolone solution or dexamethasone intravenous corticosteroids and hyaluronic acid are all available for the surgery Administer intravenous antibiotics from the Cephalosporin group and intravenous corticosteroids at least half an hour before the skin incision It is recommended to create a larger posterior tympanotomy as compared to that of a standard cochlear implantation beside the ante
37. mplants only with specified models of MRI machines Evidence has been provided for these implants to pose no known hazard in magnetic field strengths of 0 2 T 1 0 T and 1 5 T without surgical removal of the internal magnet when the following safety recommendations and guidelines are adhered to The physician MRI operator should always be informed that a patient is a cochlear implant or an auditory brainstem implant user and that special safety recommendations and guidelines have to be followed Safety recommendations and guidelines for MRI scanning e MRI scanner with static magnetic field strength of 0 2 T 1 0 T or 1 5 T only No other field strengths are allowed When using other field strengths injury to the patient and or damage to the implant are possible e MRI scan not earlier than 6 months post implantation Performing an MRI at an earlier stage may result in implant displacement and or damage to the implant e A minimum thickness of the bone underneath the implant magnet of 0 4mm is required in order to withstand forces of 5 N equals a gravitational force of about 0 5 kg or up to 9 N for the C40 cochlear implant In an MRI scanner torque forces act on the implant magnet exerting rotational pressure the device will try to turn to line up with force lines The resulting forces on the edges of the implant are counterbalanced by the cranial bone and the skin flap Bone underneath the implant magnet should be thick enough to
38. n reveal an open lumen in the further course of the scala tympani In such cases a FLEXSOFT FLEX28 or Standard Electrode Array can be inserted If the ossification is also in the ascending section of the basal turn and a drill through cannot be achieved there are various options Implant variants availability is subject to regulatory approval 30 e The cochleostomy can be widened in a superior direction to reach the scala vestibuli If this scala is patent a FLEXSOFT FLEX28 or Standard Electrode Array can be inserted e The bridge the incus and the crura of the stapes can be removed and a second cochleostomy can be drilled An implant with a Split Electrode Array can be used lower inserting one electrode array into the cochleostomy and the other into the upper cochleostomy e The Compressed Electrode Array can be Inserted into the tunnel which has been drilled into the lower basal coll Complete Ossification In cases of complete ossification the Split Electrode Array can be used Two tunnels are drilled one in the lower and one in the upper basal turn The shorter 5 channel electrode array is inserted into the upper basal coil and the longer 7 channel electrode array into the lower basal coll Insertion Test Tools Evaluation of possible electrode insertion length for the individual patient should be done prior to the surgery This can be performed by a standard X ray or a CT scan With the help of the I
39. ncisions can be extended posteriorly in the shape of an arc 20 Figure 23 Minimal incision left picture and lazy S incision right picture right ear Figure 24 Minimal incision left picture and lazy S incision right picture right ear close up Surgical procedure STEP 4 A Open Skin Flap The incision is made and the wound is held open by retractors At all times care should be taken to ensure that the flap is kept moist with damp surgical gauze Either a single layer skin flap all four layers skin subcutis muscle and periosteum are incised in a single cut or a double layer skin flap can be performed A double layer skin flap may e reduce the chance of infection because the incisions are at different locations and layers and e allow better healing so it is often used for re implantations and when encountering postauricular scar formation Double layer skin flap see Figure 25 The four different tissue layers skin subcutis muscle and periosteum are incised with two different incisions First the skin subcutis and muscle are raised and retracted Second the periosteum Is incised the periosteum Is freed from the surface of the bone and then retracted in another location Various methods may be used when incising the periosteum Care should be taken to avoid incision over the implant later on STEP 4 B Skin Flap Thickness In order to achieve good magnetic hold and optimal si
40. nsertion Test Tool the Insertion Electrode IE the surgeon can establish whether the cochlear lumen is obstructed or if it is freely accessible up to different insertion depths depending upon the considered electrode variant planned for the implantation The Insertion Electrode variants shall not be used in patients where residual hearing shall be preserved Surgical procedure FLEXSOFT A 31 5mm electrode array featuring FLEX tip technology for increased mechanical flexibility and enabling CCC Order number 04215 FLEX28 A 28mm electrode array suitable for 96 of all normal cochlear duct lengths featuring FLEX tip technology Optimised for insertion into the apical region CCC Order number 08361 FLEX24 A 24mm electrode array featuring FLEX tip technology and designed for combined Electric Acoustic Stimulation EAS with insertion less than 1 5 turns Order number 04214 FLEX20 A 20mm electrode array featuring FLEX Tip technology and designed to be used in cases of partial deafness or for other specific needs or surgical preferences Order number 30968 FORM24 A 24mm electrode array featuring CSF SEAL designed for open no obliteration or ossification or malformed cochleae especially Type I malformations Also for cases where CSF leakage is expected Order number 30662 FORM19 A 19mm electrode array featuring CSF SEAL designed to be used in cochleae with malformation especially T
41. nsertion angle to reach a tangential electrode insertion Surgical procedure The electrode lead is held very carefully at the proximal thicker part just above the marker ring If using a FLEX style electrode array orient the single contacts along the apical portion of the array toward the modiolus of the cochlea during insertion so that the marker dot at the base of the array will point toward the modiolus after insertion The tip of the electrode array is guided toward the cochlea opening After the tip is gently maneuver further into the cochlea griping of the electrode array between the contacts can be done see Figure 46 During insertion it is essential that the electrode contacts are not mechanically damaged and that no excessive force should be used After the electrode array is fully inserted the marker ring will seal the cochlea opening Please be aware that sealing of the cochlear opening with the marker ring should not be achieved with the Medium and Compressed Electrode Arrays Figure 46 Detail of electrode insertion manoeuvre the electrode array between the contacts amp after the marker ring 35 Surgical procedure If resistance is encountered before reaching the marker ring the electrode array may buckle In such cases electrode insertion should be stopped Excessive force should not be used as it may result in intra cochlear damage The following measures may be helpful in such situations e Ca
42. nt a medical surgical evaluation counselling sessions and when possible a psychological assessment To obtain the optimal benefit from the implant candidates should be sufficiently motivated and understand the importance of returning to the implant centre for regular audio processor programming training and assessment sessions The medical evaluation prior to cochlear implant surgery serves to e assess the candidate s health status and ability to undergo surgery e verify the absence of disease and infection of the outer and middle ear e screen for cochlear obliteration and other obstacles to electrode insertion e rule out central auditory lesions and verify a functional auditory nerve The above evaluations usually involve an otologic otoscopic examination and a CT scan and or MRI If there are concerns about the integrity of the upper auditory pathways and auditory lesions an MRI is necessary It is important to realise that there are a variety of conditions that predispose a person to contracting bacterial meningitis irrespective of cochlear implantation such as malformations of the inner ear history of recurrent meningitis the presence of CSF leaks etc There is no evidence that implantation of a MED EL device increases the risk for postoperative meningitis MED EL encourages all cochlear implant candidates and recipients especially individuals with cochlear malformations and other risk factors to discuss with t
43. ochleostomy is made inferior and slightly anterior to it Many surgeons have a preferred technique to locate the best promontory point to begin drilling the cochleostomy One recommendation is to use the width of the stapes as a measuring tool The cochleostomy Is made inferior to the stapedial tendon at a distance twice the width of the stapes and inferior and slightly anterior to the round window 28 Figure 35 Removal of a mucosal fold amp marking of cochleostomy right ear Figure 36 Drilling the cochleostomy inferior and slightly anterior to the round window right ear Surgical procedure The cochleostomy is drilled and the exposure of the endosteum should be big enough to comfortable fit the electrode An appropriate cochleostomy size is dependent upon the type of electrode array chosen Please refer to STEP 9 Select Appropriate Electrode Variant The bony lip of the cochleostomy is slightly smoothed with a small diamond drill bit Begin drilling near the cochlea use a slowly turning diamond drill to avoid acoustic trauma e The cochleostomy should be drilled inferior and slightly anterior to the round window annulus to achieve a scala tympani insertion and to avoid damage to the osseous spiral lamina The endosteum should be exposed to approximately 0 8mm e Fill the electrode insertion site with corticosteroid e Protect the middle ear cavity from bone dust contamination
44. of Insertion Speed on Inner Ear Function during Cochlear Implantation A Comparison Study Rajan GP Kontorinis G Kuthubutheen J Audiol Neurootol 18 1 2012 Sep 22 p 17 22 Concerto Pin A Novel Concept of Cochlear Implant Fixation Schnabl J Markl A Hormann R Wolf Magele A Schartinger V Sprinzl G Otol Neurotol 2012 Depth of Electrode Insertion and Postoperative Performance in Humans with Cochlear Implants A Histopathologic Study Lee J Nadol JB Eddington DK Audiol Neurootol 15 5 2010 323 331 Cochlear implantation in inner ear malformations Sennaroglu L Cochlear Implants Int 2009 Scala tympani cochleostomy l results of a survey Adunka OF Buchman CA Laryngoscope 2007 117 12 2187 2194 Cochlear implant electrode insertion The round window revisited Roland P Wright C Isaacson B Laryngoscope 2007 117 8 1397 402 Scala tympani cochleostomy Il Topography and histology Adunka O Radeloff A Gstoettner W Pillsbury H Buchman G Laryngoscope 2007 XX 1 6 Preservation of basal inner ear structures in cochlear implantation Adunka O Gstoettner W Hambek M Unkelbach MH Radeloff A Kiefer J ORL J Otorhinolaryngol Relat Spec 2004 66 6 306 12 Cochlear implantation via the round window membrane minimizes trauma to cochlear structures A histologically controlled insertion study Adunka O Unkelbach MH Mack M Hambek M Gst ttner W and Kiefer J Acta Otolaryngol 2004 124 807 812 48 Th
45. opolar diathermy has been used it must now be disconnected High current levels may cause damage to the implant If bipolar cautery must be used the tips of the cautery should be kept at least 3cm away from the implant Figure 39 Implant e Additional immobilisation of the implant needs to be immobilised with a single performed stitch right ear e If sutures are chosen for immobilisation of the implant do not place the sutures directly over the electrode lead Additional immobilisation of the implant needs to be performed e g with sutures It should be conducted in such a way that there will be no postoperative movement Continuous movement may result in mechanical fatigue Figure 40 Implant and subsequent premature failure of electrical connections immobilised with double stitches right ear When the implant is immobilised with sutures the holes drilled in STEP 7 should be used to secure the implant in its bed and the electrode should be placed into the drilled channel leading into the mastoid Make sure the electrode channel is deep enough to prevent the tie down from exerting pressure and damaging the electrode MED EL recommends the use of the following techniques details in Figure 39 Figure 40 In the event that the placement of the implant led to the protrusion of the reinforced part of the electrode into the mastoidectomy the following measures should be undertaken e Gently pre shape the reinforced par
46. pical end 0 5 x 0 3mm Figure 5 FLEX20 Electrode Array FORM 24 Order Number 30662 The FORM24 Electrode Array see Figure 6 is 24 mm long electrode array designed for open no obliteration or ossification or malformed cochleae especially Type Il malformations It features 12 evenly spaced electrode pairs spaced over 18 7 mm with 1 7 mm spacing between each contact pair The FORM24 electrode array features an integrated SEAL function designed to close off the cochlear opening SEAL is a 2 4 mm conical thickening located at the basal end of the array designed to control the leakage of cerebrospinal fluid CSF also known as gusher 24mm 2 4mm i n Active Stimulation Range ASR 18 7mm 0 A w din Min Min 219mm 0 8mm 20 5mm CSF SEAL 24 platinum electrode contacts Optimal spacing over a 18 7mm stimulation range Diameter at basal end 0 8mm CSF SEAL 4 Diameter at apical end 0 5mm Figure 6 FORM 24TM Electrode development was in close collaboration with Prof Levent Sennaroglu Department of Otolaryngology Hacettepe University Medical Faculty Turkey Technical description of the implant FORM 19TM Order Number 30663 The FORM19 Electrode Array see Figure 7 is 19 mm long electrode array designed intended to be used in cochleae with malformation especially Type I and Type Ill obliteration or ossification It features 12 evenly spaced electrode pairs spaced ov
47. plantation a new treatment modality for children with drug induced or congenital partial deafness Kuthubutheen J Hedne CN Krishnaswamy J Rajan GP Audiol Neurootol 2012 17 5 321 30 Cochlear implantation and hearing preservation Results in 21 consecutively operated patients using the round window approach Erixon E Kobler S Rask Andersen H Acta Otolaryngol 2012 Achievement of hearing preservation in the presence of an electrode covering the residual hearing region Usami SI Moteki H Suzuki N Fukuoka H Miyagawa M Nishio SY Takumi Y Iwasaki S Jolly C Acta Otolaryngol 2011 Combined electric acoustic stimulation with the PULSARCI 100 implant system using the FLEX EAS electrode array Helbig S Van de Heyning P Kiefer J Baumann U Kleine Punte A Brockmeier H Anderson I Gstoettner W Acta Otolaryngol 2011 Atraumatic round window deep insertion of cochlear electrodes Skarzynski H Lorens A Zgoda M Piotrowska A Skarzynski PH Szkielkowska A Acta Otolaryngol 2011 Hearing Preservation After Complete Cochlear Coverage in Cochlear Implantation With the Free Fitting FLEX Electrode Carrier Helbig S Baumann U Hey G Helbig M Otol Neurotol 2011 Jul 1 Is Electric Acoustic Stimulation Better Than Conventional Cochlear Implantation for Speech Perception in Quiet Adunka OF Pillsbury HC Adunka MC Buchman CA Otol Neurotol 2010 Electric Acoustic Stimulation in Patients with Postlingual Severe Hig
48. plete Cochlear Coverage The contacts for the 12 channels are arranged as 5 single contacts at the apical array end and 7 contact pairs at the base with a 2 4mm spacing between each channel The specially designed electrode tip offers increased mechanical flexibility for reduced insertion force The marker ring is located 31 5mm from the electrode tip and indicates the deepest insertion Near the marker ring the electrode lead features an additional marker dot on the same side of the array as the single apical contacts The marker allows the Surgeon to ensure appropriate alignment of the single contacts toward the modiolus 31 5mm Active Stimulation Range 26 4mm 3 N Min A 0 5 x 0 4mm 1 3mm H i FLEX Tip 19 platinum electrode contacts Optimal spacing over a 26 4mm stimulation range Diameter at basal end 1 3m FLEX Tip for minimal insertion trauma Dimensions at apical end 0 5 x 0 4mm Figure 2 FLEXSOFT Electrode Array Technical description of the implant FLEX28 Electrode Array Order number 08361 The FLEX28 Electrode Array see Figure 3 is 28mm long featuring FLEX tip technology suitable for 96 of all normal cochlear duct lengths The contacts for the 12 channels are arranged as 5 single contacts at the apical array end and 7 contact pairs at the base with a 2 1mm spacing between each channel The specially designed electrode tip offers increased mechanical flexibility for reduced insertion
49. preservation in cochlear implant surgery Roland P Gstoettner W Adunka O Otolaryngol 2005 16 93 100 Conservation of low frequency hearing in cochlear implantation Kiefer J et al Acta Otolaryngol 2004 124 272 280 The following is a list of references on young children Functional outcome of sequential bilateral cochlear implantation in young children 36 months postoperative results Scherf FW Van DL van WA Wouters J Desloovere C Dhooge I Offeciers E Deggou N De RL De BM Van de Heyning PH Int J Pediatr Otorhinolaryngol 2009 Feb 26 50 Ear Surgery in Infants Under One Year of Age Its Risks and Implications for Cochlear Implant Surgery Johr M Ho A Wagner CS Linder T Otol Neurotol 29 3 2008 Apr p 310 313 Surgical Factors in Pediatric Cochlear Implantation and Their Early Effects on Electrode Activation and Functional Outcomes Francis HW Buchman CA Visaya JM Wang NY Zwolan TA Fink NE Niparko JK Otol Neurotol 2008 Apr 4 Hearing benefits of second side cochlear implantation in two groups of children Scherf F van Deun L van Wieringen A Wouters J Desloovere C Dhooge I Offeciers E Deggou N De Raeve L De Bodt M Van De Heyning P Int Pediatr Otorhinolaryngol 71 12 2007 Dec p 1855 1863 Simultaneous versus sequential bilateral implantation in young children Effects on central auditory system development and plasticity Sharma A Gilley P Martin K Roland P Bauer P Dorman M Audiological M
50. re 42 Endosteum incision with a 45 micro hook Figure 43 Endosteum incision with a micro lancette 33 Surgical procedure STEP 12 Insert the Electrode Array CAUTION BE e Only surgical tools approved by MED EL should be used to insert the electrode array into the cochlea e Under no circumstances should any force be used during electrode insertion e Insertion of the electrode array into the cochlea will probably destroy remaining hearing that was present in that ear prior to surgery It is important for the electrode array to approach the anterior portion of the basal turn at an angle so that it Slides along the lateral wall of the scala tympani This procedure known as tangential insertion facilitates deep electrode insertion see Figure 44 The individual insertion angle for each case should be considered in order to reach a tangential electrode insertion see Figure 45 Non tangential insertion should be avoided Surgical tools approved by MED EL should be used to Insert the electrode array into the cochlea Either the Surgical Claw or the Micro Forceps Angled can be used to maneuver the electrode array The type of Micro Forceps Angled used to insert the electrode in a left or a right cochlea depends on the preference of the surgeon Use of lubrication or anti inflammatory compounds during electrode insertion is up to the surgeon 34 Figure 44 Direction of electrode insertion right ear Figure 45 I
51. refully rotate the electrode Due to the unique oval design of the electrode array the electrode can be slightly rotated to allow it to slide deeper into the cochlea Small movements close to the insertion site Hold the electrode no more than 2mm from the cochleostomy or round window opening Gently insert the electrode with one stroke release it and grasp it again 2mm from the insertion side Repeat this procedure until complete insertion is achieved e Slow the rate of insertion Slow the speed that the electrode is introduced into the opening Frequent pauses during Insertion can allow the electrode to gently slide along the cochlear duct e Use of lubricant As known from soft surgical techniques the use of a lubricant can help smoothing the electrode insertion e Immediately start the electrode insertion through the drop of corticosteroid and hyaluronic acid e General insertion direction is from superior posterior to anterior inferior with the knob indicating the direction of the apical electrodes facing towards the modiolus 36 Figure 47 Full insertion of the electrode array forceps positioned behind the marker ring right ear Surgical procedure STEP 13 A Seal Cochlear Opening CAUTION e Once the electrode array has been inserted into the cochlea the electrode lead should be fixed so that no postoperative movement will occur e Please be aware that sealing of the cochlear openin
52. retracted in another location Various methods may be used when incising the periosteum Care should be taken to avoid incision over the implant later on 24 Long process of the incus m Chorda tympani Short process of the incus Stapedius tendo RW niche Bony buttress Figure 29 Posterior Tympanotomy microscopic view right ear Figure 30 Double layer skin flap right ear Surgical procedure STEP 7 Drill Stimulator Bed and Electrode Channel CAUTION Eee e The implant must be immobilised in a flat stimulator bed drilled in the temporal bone The electrode lead should be placed in a ramp like bony channel without Sharp edges to protect it against postoperative movement and excessive mechanical impact e The anterior stimulator edge should not be recessed to a depth more than 2 mm e All sharp edges of bone must be removed in order to avoid possible damage to the electrode lead Drilling should be completed before the cochlea is opened to prevent any bone dust from entering e Protect the middle ear cavity from bone dust contamination by closing it with medical gauze The implant must be immobilised in a flat stimulator bed drilled in the temporal bone In adults it may not be necessary to expose the dura but in small children with a thin skull drilling to the dura may sometimes be required in order to ensure that the stimulator is well recessed in its bed If drilling down to the dura is necessa
53. rior tympanotomy in order to provide a better view as well as more space to manoeuvre the electrode array Elevate a mucosal flap to avoid mucosal bleeding when opening the cochlea Begin drilling near the cochlea use a slowly turning diamond drill to avoid acoustic trauma To enter the middle portion of the scala tympani and to The cochleostomy should be drilled inferior and slightly get visualization of the round window membrane the anterior to the round window annulus to achieve a scala posterior superior lip of the round window niche and the tympani insertion and to avoid damage to the osseous inferior margin of the round window should be drilled away spiral lamina The endosteum should be exposed to to expose the round window membrane at least 0 8 mm approximately 0 8 mm Fill the electrode insertion site with corticosteroids Protect the middle ear cavity from bone dust contamination by closing it with medical gauze Drill the implant bed and immobilise the implant Prior to opening the cochlea clean the surgical field change gloves remove the gauze used to keep bone dust out of the middle ear cavity Place a drop of corticosteroid on the round window membrane or endosteum to reduce fibrotic reaction and cover it with a drop of hyaluronic acid This will keep the corticosteroid in place and protect it from bone dust Figure 59 Hearing Preservation Surgical Technique Part 1 46 Appen
54. ry a bony island should remain Ideally the stimulator is recessed approximately 2mm Once again the Implant Template Single Use for the SONATA can be used to mark the flatness on the skull and the correct position for the implant bed see Figure 31 For protection and placement of the electrode a smooth channel has to be drilled in the bone leading to the mastoid Make sure that the channel is deep and wide enough to comfortably accommodate the electrode If for example the implant is fixed with sutures a diamond burr should be used to drill the holes so that the implant can be immobilised later The suture holes should be drilled such that the sutures do not cross the electrode but rather only cross the silicone over mold see Figure 32 Figure 31 Marking the implant position with the Implant Template right ear Figure 32 Flat stimulator bed electrode channel and suture holes for single stitch right ear 25 Surgical procedure STEP 8 VARIANT 1 Preparation Tor a Round Window opening CAUTION e Always use a slow turning diamond drill to avoid acoustic trauma when drilling the round window RW niche approx 1000rpm e Try to keep the RW membrane intact until the insertion of the electrode A clear view of the RW membrane is fundamental for the successful performance of a round window opening Therefore the posterior tympanotomy is usually slightly bigger drilled than a standard posterior tymp
55. s F rstenweg 77a 6020 Innsbruck Austria office medel com medel com N w
56. t of the electrode lead without surgical instruments using your hands only e Try to coil the rest of the electrode lead into the mastoidectomy in such a way that additional pressure is not placed on the outer ear canal or the periosteum closing the mastoid cavity 32 Surgical procedure STEP 11 Opening the Cochlea Before inserting the electrode array into the cochlea either the RW membrane for a RW insertion or the endosteum for a cochleostomy insertion needs to be incised Either a micro lancette or a micro hook can be used to open the cochlea see Figure 41 Figure 42 and Figure 43 e Prior to opening the cochlea clean the surgical field change gloves remove the gauze used to keep bone dust out of the middle ear cavity and administer a single dose of intravenous corticosteroids to protect the inner ear e Place a drop of corticosteroid on the round window membrane or endosteum to reduce fibrotic reaction and cover it with a drop of hyaluronic acid This will keep the corticosteroid in place and protect it from bone dust e Using a micro lancette or micro hook carefully incise the round window membrane in its inferior anterior quadrant to approximately 0 8mm e Using a micro lancette or micro hook carefully incise the endosteum to approximately 0 8mm e Avoid suctioning in the open region of the cochlea Figure 41 RW membrane incision with a 45 micro hook Figu
57. task it is necessary to also use a separate neurodiagnostic computer with a trigger input along with scalp recording electrodes ART Auditory Nerve Response Telemetry MED EL offers implants that are capable of recording compound action potentials small voltage changes that are created by the auditory nerve when it transmits a signal to the brainstem The measurement is done a few microseconds after the end of a stimulation pulse The recorded signal is called the Evoked Compound Action Potential ECAP or EAP of the auditory nerve It has an amplitude of about 0 01 to 2mV and takes place within roughly one millisecond after the stimulation pulse Due to these very short small response levels special artifact reduction methods are used to enhance viewing of the nerve response 4l Surgical procedure STEP 15 Close Wound For additional immobilisation of the implant and the electrode lead the periosteum should be separately sutured over the implant region and the mastoid cavity Care should be taken not to damage the implant or the electrode The rest of the wound should be closed in layers with staples or absorbable subcutaneous sutures The area of the wound is covered with a compress and sterile gauze applying even pressure e A course of steroids and antibiotics should be given postoperatively 42 Appendix Appendix MRI Caution MRI is possible in patients with cochlear or auditory brainstem i
58. telemetry mode the device allows a functional check about the technical status of the implant including communication over the transcutaneous link as well as the assessment of the electrode impedances and recording of the electrically evoked compound action potential of the hearing nerve The electronics of the SONATA contain a powerful custom made circuit that is capable of processing large amounts of information at a very rapid rate It can stimulate at 50 704 pulses per second This capability makes the implant compatible with a wide range of pulsatile processing strategies and future developments in speech processing A telemetry feature enables the clinic to verify the functional status of the implant within a matter of seconds For added safety each output has a capacitor to prevent any possible leakage of DC current to the auditory nerve Figure 1 SONATA Cochlear Implant dimensions in mm typical values Technical description of the implant Performance Characteristics e Output characteristics of a stimulation signal on a 1 kOhm resistor Maximum current amplitude Median value 1250 uA range 500 uA Maximum pulse width Median value 203 8 us range 8 2 us e The impedance measurement accuracy is typically better than 5 e When keeping to the safety guidelines the implant is conditionally MRI safe for MR scanner field strengths of 0 2 Tesla 1 0 Tesla and 1 5 Tesla e There are no d
59. ts toward the modiolus 24mm o Active Stimulation Range 20 9mm or v Mn 008 0 5 x 0 3mm omm FLEX Tip 19 platinum electrode contacts Optimal spacing over a 20 9mm stimulation range Diameter at basal end 0 8mm FLEX Tip for minimal insertion trauma Dimensions at apical end 0 5 x 0 3mm Figure 4 FLEX24 Electrode Array Technical description of the implant FLEX2O Electrode Array Order number 30968 The FLEX20 Electrode Array see Figure 5 is 20mm long featuring FLEX tip technology and designed for combined Electric Acoustic Stimulation EAS The contacts for the 12 channels are arranged as 5 single contacts at the apical array end and 7 contact pairs at the base with a 1 4mm Spacing between each channel The specially designed electrode tip offers increased mechanical flexibility for reduced insertion force The marker ring is located 20mm from the electrode tip and indicates the deepest insertion Near the marker ring the electrode lead features an additional marker dot on the same side of the array as the single apical contacts The marker allows the surgeon to ensure appropriate alignment of the single contacts toward the modiolus 20mm ASR 15 4mm oe S M 0 5 x 0 3mm amp 0 8mm FLEX Tip 19 platinum electrode contacts Optimal spacing over a 15 4mm stimulation range Diameter at basal end 0 8mm FLEX Tip for minimal insaertion trauma Dimensions at a
60. uma Dimensions at apical end 0 5 x 0 4mm 19 platinum electrode contacts Optimal spacing over a 23 1mm stimulation range Diameter at basal end 0 8mm FLEX Tip for minimal insertion trauma Dimensions at apical end 0 5 x 0 4mm 19 platinum electrode contacts Optimal spacing over a 20 9mm stimulation range Diameter at basal end 0 8mm FLEX Tip for minimal insertion trauma Dimensions at apical end 0 5 x 0 3mm 19 platinum electrode contacts Optimal spacing over a 15 4mm stimulation range Diameter at basal end 0 8mm FLEX Tip for minimal insaertion trauma Dimensions at apical end 0 5 x 0 3mm 24 platinum electrode contacts Optimal spacing over a 18 7mm stimulation range Diameter at basal end 0 8mm SEAL Diameter at apical end 0 5mm 24 platinum electrode contacts Optimal spacing over a 14 3mm stimulation range Diameter at basal end 0 8mm SEAL Diameter at apical end 0 5mm 24 platinum electrode contacts Optimal spacing over a 26 4mm stimulation range Diameter at basal end 1 3mm Diameter at apical end 0 5mm 24 platinum electrode contacts Optimal spacing over a 20 9mm stimulation range Diameter at basal end 0 8mm Diameter at apical end 0 5mm 24 platinum electrode contacts Optimal spacing over a 12 1mm stimulation range Diameter at basal end 0 7mm Diameter at apical end 0 5mm Figure 38 MED EL electrodes 31 Surgical procedure STEP 10 Immobilise the Implant CAUTION BEN e If mon
61. y at your local FENTEXmedical distributor http www fentexmedical com Implant Template for the SONATA Order number 05064 This template is used to assess the size and the position of the implant on the skull This tool is a re usable surgical instrument made from medical grade stainless steel The device is delivered non sterile 14 Figure 17 FENTEXmedical Forceps Figure 18 Implant Template for the SONATA Surgical tools Surgical Claw Straight Order number 07711 The Surgical Claw can help to position and insert the electrode array into the cochlea The tip of this instrument is straight This tool is a re usable surgical instrument made from medical grade stainless steel The device is delivered non sterile Figure 19 Surgical Claw Straight 15 Surgical tools Insertion Test Tools They are primarily used when ossification or fibrosis Is suspected to aid the surgeon in determining which electrode variant to use e g for detailed dimensions please see section Il Implant Variants Insertion Test Device ITD Order number 02081 The ITD is similar to the Standard Electrode Array in dimension and shape It has a stopper at 18 0 mm and 5 pairs of markers to help determine insertion depth up to a maximum of 18 0 mm The Insertion Test Device is delivered in sterile packaging and is a single use device only Typical dimensions in mm Figure 20 Insertion Test Device Contact spacing 2
62. ype and Type Ill obliteration or ossification Also for cases where CSF leakage is expected Order number 30663 Standard A 31 5mm electrode array designed for long cochlear duct lengths Order number 04210 Medium A 24mm electrode array designed for cases where deep insertion is not desired or is not possible due to anatomic restrictions Order number 04213 Compressed A 15mm electrode array designed for partial ossification or malformation of the cochlea Order number 04211 31 5mm Active Stimulation Range 26 4mm Min 213mm w mi a 0 5 x 0 4mm FLEX Tip 28mm Active Stimulation Range 23 1mm Me 0 5 x 0 4mm FLEX Tip 24mm Active Stimulation Range 20 9mm a 0 5 x 0 3mm FLEX Tip 20mm ASR 15 4mm 0 5 x 0 3mm Ona FLEX Tip 24mm Active Stimulation Range ASR 18 7mm a 0 5mm 4 19mm ASR 14 3mm 613mm 31 5mm Active Stimulation Range ASR 26 4mm z Zn ca gt 7 as 0 5mm 24mm Active Stimulation Range ASR 20 9mm v a aaa z SI a 2 0 8mm 0 5mm 15mm o ASR 12 1mm Ww vw ne ne a mE 2 0 7mm 0 5mm 19 platinum electrode contacts Optimal spacing over a 26 4mm stimulation range Diameter at basal end 1 3m FLEX Tip for minimal insertion tra

SONATA Surgical Guideline AW7695_5.0 - Med-El

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