Carina Conductivas Mixtas

7/27/2019 Carina Conductivas Mixtas

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Otologics Fully Implantable Hearing Systems

Surgical Guide

Carina with MET V

For Conductive & Mixed Loss A lications

01232007


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This Instruction document outlines the basic steps required to implant the Carina Fully ImplantableHearing Device with the MET V transducer for treatment of conductive and mixed hearing losses. Itis not intended to contain all information relating to the Otologics implant and its components.Refer to Otologics Surgical Training Manual D104096 for additional information.

Step 1 Planning Capsule Placement and Making the Incision

Prior to surgery an implant model or capsule template is used toidentify the optimal implant placement and location of the incision.

See dotted line in Figure 1.

The implant capsule and coil are placed in a relatively flat regionof the head. The capsule is placed in a bone bed so that it does not

protrude more than ~2mm above the surface of the skull . Bending

of coil more than 10 relative to capsule may cause damage, and

often results in longer charging times for the patient.

The optimal position of the implant capsule typically lies betweenlines of 30 and 90 degree angle relative to the horizontal with thesilicone charging coil superior to the titanium capsule body, asshown in figure.

The microphone must be firmly anchored to bone, and away

from muscle. Proper position is directly posterior to ear canal.Deviations from this position may result in feedback and other

performance issues for the patient.

CAUTION: Do not allow any of the implant

components to touch each other.


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Step 2 Assembling the Prosthesis Guide

The Bending Guide with Prosthesis Template provides important guidance in drilling the mastoidectomy. Assemble the Bending Guide withProsthesis Bending Template as shown below. Set the compression assemble to the middle of its range, to ensure that the real transducer willhave some forward and backward adjustability available.

It is recommended that 5mm of the prosthesis template extendbeyond the mock transducer, which approximates the length of theMET V transducer with full length prosthesis. If the anatomy orplacement of the bracket requires less than 5mm, this implies that

the prosthesis will need to be cut to match the prosthesis template.

Important: Do not extend the prosthesis template more

than 5mm or less than 1mm beyond the Bending Guide,as this simulates a transducer length that cannot be

achieved.

Example of Prosthesisbent and crimped tomatch.

This represents the length of aMET V with the longest possibleprosthesis.

5mm

Set compression

assembly of BendingGuide to the middle of its

range as shown

Tighten Locking Colletto Secure Prosthesis

Template

Bendable andExtendable tip

Bending Guide assembledwith Prosthesis Templateand Locking Collet

Locking ColletHolds template in position

Prosthesis Template

Formable wire with ball tip

Transducer BoneMounting Bracket

Locking Tool


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Step 3 Drill the Mastoidectomy and Facial Recess

Overview: The surgical approach for placement of the MET V

transducer is typically through the facial recess. From this approach,the prosthetic transducer tip can be connected to the desired middleear anatomy; stapes superstructure; stapes footplate; oval window;round window; or other ossicular structure.

Procedure: Drill a mastoidectomy to expose the facial recess. A fullmastoidectomy is not usually needed.

Use the Prosthesis Guide to determine the appropriatesize and location of the mastoidectomy.

The mastoidectomy only needs to be large enough to accommodatethe transducer and bracket. Open the facial recess to gain access tothe middle ear.

(NOTE: If a larger mastoidectomy has been drilled in a previousprocedure, a special bone bracket may be necessary to span the

larger opening.)

Left Ear


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Step 4 Positioning and Fastening the Mounting Bracket

Preliminary Placement Place the mounting bracket so

that the Prosthesis Template can reach the desired middle

ear anatomy. Bend the wire of the Prosthesis Template as

needed to achieve an effective approach to the desired

contact point.

Perform additional drilling as necessary to allow proper

placement of the bone bracket and Bending Guide.

Important: Do not extend the Prosthesis Templatemore than 5mm or less than 1mm beyond the mocktransducer, as this simulates a transducer length thatcannot be achieved.

The mounting bracket legs should be bent to allow flush

placement against the cortex.

Fastening: Once the bracket legs have been bent to

conform to the cortex, and the Prosthesis Template is able

to contact the desired anatomy, drill a hole in each of the

bracket legs. Screw down all four legs with at least onescrew each.

Final Adjustments to Prosthesis Template: After

fastening the bracket to the skull, final adjustment to the

Prosthesis Template may be made by loosening the

Locking Collet and/or carefully bending the prosthesis tip

with an instrument.

After all adjustments are complete:

Tighten the Locking Collet to maintain the position ofthe prosthesis template

Loosen the Locking Tool.Carefully remove the entire Bending Guide assembly

from the mounting bracket.

Always maintain a hold on the Bending guide as it is

loosened so that it does not slip and contact the

ossicles.

Loosen the Locking Tool and move the BendingGuide as shown in the diagram to alter the angle ofthe Prosthesis Template. This will also allow forwardand backward adjustment of the Bending Guide.

If necessary, loosen the Locking Collet for additionalforward or backward adjustment of the ProsthesisTemplate.

Left Ear

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Step 5 Transducer Health Verification

Transducer Health

After removing the MET V transducer from the sterile package, connect the sterile TLA IS-1 clip cable and start the TLA

software.IMPORTANT: The tip of the transducer is delicate, handle carefully and avoid contact with tip.

Run Initialization to ensure that the transducer is healthy Typically, initialization results in a Green reading.

NOTE: If TLA gives a yellow Initialization with MET V, look for 2 other things to know the transducer is healthy:

1. The Initialization values displayed on the right side of the software are in the 150-1300 range.2. A normal Inductance value of 16.5 to 13 mH is measured after clicking Run

In determining transducer health, the Inductance values is just as important as Initialization. Once the Run button has been

pressed, TLA should indicate an Inductance value of 13-16.5mH.

Connect cable to transducer lead.

Initialize TLA

TLA Initialization is a

measurement of transducerimpedance. Most of thevalues are typically be in the

range 150-400, with a peak

value of 600-1300 identifiedby the green indicator.


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Transducer Monitoring

Run TLA and monitor the Inductance and Impedance values to monitor transducer health

and ensure that transducer is being handled within safe limits.

IMPORTANT: During handling, crimping, and placement, the TLA Inductance

value should remain above 10mH most of the time and should not drop below 7mH.

An inductance value below 7mH indicates that the transducer is being handled

outside its operational limits. If Inductance reading drops below 7mH, reduce the

contact/loading of the transducer tip and ensure that Inductance returns to >12mH.

Carefully place the transducer into the crimper as shown bellow. Push the transducer forward until it stops, so that the middle of

the transducer tip is between the crimping pins. MAKE SURE THE TRANSDUCER LEAD IS NOT UNDERNEATH THE

HANDLE, TO AVOID DAMAING THE LEAD WHEN CRIMPING.

SLIDE TRANSDUCERFULLY FORWARD

Inductance


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Step 6 Prosthesis Shaping, Cutting, and CrimpingOnce the Prosthesis Guide has been bent to achieve contact with the desired anatomy, remove the Prosthesis Guide from the bone

bracket and place the entire assembly complete into the base of the crimper tool as shown. Ensure that the transducer portion of

the laser guide is all the way forward as the arrow indicates.

Slide

forward as

shown.

Place prosthesis in hole on end ofcrimper tool.Continue to hold with tweezers donot let go at any time. Use one pair tohold the base of the prosthesis at the

edge of the crimper block, and theother to manipulate and cut to length.Cutting line providescorrect final length.

Replicate bends onoverhanging portion

onl

NOTE: The edge of

the crimper

represents the end of

the MET V

transducer

Important: Crimper blockdoes not hold prosthesissecurely. A firm grip mustbe maintained on theportion that is to be used.


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Place the MET V Attachment prosthesis in the tip of the MET V Transducer. Rotate and align MET V Transducer attachment so

that it matches the Prosthesis Guide as shown in diagram. Slide the MET V Transducer Attachment wire all the way into the

transducer tip as far as it will go (2mm). The TLA readings will respond during this process, however they must return to the

range of a healthy transducer once the crimp is complete, as detailed in the following steps.

It is critical to the reliability of the crimp joint, that the MET V Transducer Attachment wire is inserted fully.

While the MET V Transducer Attachment wire is inserted the full 2mm, the crimp is made by pushing down firmly on the handle

once and only once, until it hits the stop.

NOTE: Cut in a rockingmotion with a roundedblade. DO NOT use aslicing motion.

The discarded portion of the prosthesiswire will remain inside the fixture in thisslot.

Transfer cut prosthesis to the tip of thetransducer in the same orientation as the

bendin tem late uide.


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You may now release the crimper handle and the MET V Attachment. Verify attachment with a gentle tug.

Verify TLA readings indicate a healthy transducer, i.e. >12mH Inductance; >500 Ohms Impedance.

The MET V Transducer may now be removed from the crimper. Press the ejector button as shown below to raise the transducer.

Gently grab the case of the transducer (DO NOT grab the tip of the transducer OR the prosthesis tip!) and lift it up and out.

Insert MET V Attachment fully.Monitor TLA Inductance.

While gently holding MET Vattachment, firmly press

the crimper handle, all theway down, until it hits the

stop.

DO THIS ONLY ONCE


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Step

7Mounting the MET V

Transducer

Place the locking ring firmly onto the Locking Tool.

Slide the Locking Tool onto the Insertion Instrument

Joystick. Grasp the MET V transducer with the

thumbscrew and joystick assembly.

Again, the TLA software should be monitoring thetransducer during these steps. Guide the transducer

into the mounting bracket, taking care to preserve the

shape of the prosthesis as much as possible. Place the

transducer such that the prosthesis attachment is near

the target anatomical site. Tighten the locking ring to

secure the transducer.

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The transducer and prosthesis can be advanced by using the micro-adjust. Additional shaping of the prosthesis may be necessary,

however the end of the MET V transducer is delicate and care must be taken when performing manipulations of the prosthesis

attachment. If possible, stabilize the transducer tip with one instrument while manipulating the prosthesis with another. Monitor

TLA software to guide final placement of transducer, as described below. TheTLA software inductance value is used to ensure

that manipulations of the prosthesis do not over-stress the transducer.

Final Placement ofProsthesis TipStep 8

Placement of MET V transducer on stapes capitulum

Left Ear

Placement of MET V transducer on

round window

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Understanding TLA: The TLA software should be used to monitor the transducer throughout final placement. Keep in mind that

TLA measures pressure on the tip of the transducer. With the MET V prosthesis tip, there may not be as much pressure on the

transducer as with standard incus placement; therefore, TLA loading guidelines are different for MET V.

Proper Visualization of Prosthesis is Critical!

Transducer Health: Use TLA

Inductance as a monitor of

transducer health. The Inductance

may change very little, or it may

drop 2 mH or more, depending on

how much pressure is exerted back

through the prosthesis to the

transducer. Final loading is

typically within 2mH of the initial

Inductance value measured with

transducer in free air. Final

inductance MUST be >12mH.

Transducer Contact: Use TLA

Impedance as an indicator of

transducer contact. The TLA

Impedance value will often drop by

several hundred Ohms when the

transducer tip makes contact.

However, it is not necessary to

achieve 12mH.


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Is monopolar only forbidden with electronics or also with the transducer???

Step

9

Securing the Electronics,SAFI Testing, and Closing

the Incision

IMPORTANT: Place the microphone posterior to thepinna, away from any musculature. Muscle movementcan cause unwanted noise for the microphone.

Although the implant capsule and coil have been designedfor long term implantation, care must be taken wheninserting the coil into a tissue pocket. Excessivemanipulation or bending of the coil can damage it. Inaddition, the coil should be placed such that it is not bentmore than 10relative to the implant capsule.

Place the implant electronics capsule in the bone bed andsecure with two bone screws. Place the microphone in thebone bed pocket and secure with two screws. Rememberthat no implant component may touch any other, as this willreduce performance and my cause feedback. Thetransducer and microphone leads should be free of tensionand sharp bends.

Verify that the skin flap is no thicker than 6mm. Thin downas necessary to ensure that the charger andprogramming coil will properlycommunicate with the implant once skin iscovering the implant. Take care to avoiddamage to the electronics or lead duringsuturing.

CAUTION: Once the electronics havebeen implanted, only bi-polarcauterization is permissible. The use ofmono-polar cauterizing equipment maydamage the electronics.

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Test the system with the SAFI software for

final functionality confirmation before

suturing. With MET V, it is acceptable to

have a resonance peak on the SAFI

Impedance test, as shown. This peak may

even extend above the upper red line.

Typically, if there is a peak in the SAFI

Impedance data, this peak will correspond to

the frequency which was selected by the TLA

software (green or yellow bar) during

Initialization, and the value will be similar tothe final TLA Impedance value measured.

SAFI Impedance and TLA impedance are

similar measurements, and the SAFI

Impedance chart will usually have similar

values to the TLA Initialization bands.

Similar ValueSAFI Peak value similar to

TLA final loading value

Similar FrequencySAFI Peak frequency similar

to TLA Initializationfrequency

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