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Endaural Approach

last modified on: Tue, 01/16/2018 - 12:12

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  1. GENERAL CONSIDERATIONS -
    1. Indications:
      1. Conductive hearing loss due to perforation or ossicular dysfunction
      2. Chronic or recurrent OM secondary to contamination (preferably want a "dry ear" prior to proceeding)
      3. Perforation or hearing loss persistent for greater than 3 months due to trauma, infection, or surgery
      4. Inability to bathe or participate in water sports
    2. Note: similar in general to post-auricular tympanoplasty with indications differing in:
      1. whether perforation has significantly involved annulus fibrosus that would lead to problems with seating graft anteriorly from posterior approach
      2. whether attic is involved with cholesteatoma and adequate visualization would not be feasible from posterior approach
  2. Contraindications:
    1. Labyrinthine fistula
    2. Meningeal involvement
    3. Malignancy
    4. relative: active otitis, eustachian tube dysfunction (greater risk for failure), smokers, slag injury
  3. Complications:
    1. Failure to resolve perforation
    2. Recurrent perforation
    3. Facial nerve injury, damage or disarticulation of ossicles
    4. cholesteatoma (EAC, ME, TM)
    5. Dysgeusia (chorda injury)
    6. Blunting
    7. Lateralization
    8. SNHL
    9. Vertigo
    10. FN injury with paresis/paralysis
  4. PREOPERATIVE PREPARATIONS
    1. Consent - including laterality
    2. Up to date audiometry
    3. General tympanoplasty guidelines:
      1. Wullstein (1956) classification of tympanoplasty: 
        1. Type I - graft to intact ossicular chain, 
        2. Type II - Malleus is partially eroded, TM +/- malleus remnant grafted to the incus, 
        3. Type III- malleus and incus are eroded, TM is grafted to stapes suprastructure, 
        4. Type IV - stapes suprastructure is eroded but foot plate is mobile, TM grafted to foot plate, 
        5. Type V - TM is grafted to fenestration in the horizontal SCC
      2. Anatomy
        1. Tympanic membrane is oval in shape
        2. TM is 8 x 10 mm, middle ear cleft about 5 mm deep
        3. 55 degrees to the floor of the meatus
        4. 3 layers - 130 microns thick: outer layer is keratinizing squamous, middle is fibrous, and inner is mucosa
        5. Blood supply: Inner surface - anterior tympanic a.  Outer surface- Deep auricular a.
          1. When performing an endaural approach, the incision comes out the ear canal toward the temporalis muscle.  As you cross the lateral EAC bone, there is usually a large vessel that needs to be cauterized.  If not performed adequately, profuse bleeding from this area can occur during packing removal.  Recognize this and try to cauterize this area when making the incision.
  5. NURSING CONSIDERATIONS
    1. Room Setup
      1. Hang consent, H&P and most recent audiogram on wall.
    2. Instrumentation and Equipment
      1. Lempert endaural speculum
      2. Modified Richard's self-retaining retractors x 2
  6. Medications (specific to nursing)
    1. 0.5% lido w/ epi (1:200,000) for preauricular incision for childre
    2.  2% lido with 1:20,000 epi in adults
  7. Prep and Drape - in adults, can be done under local anesthesia similar to Stapedotomy/stapedectomy protocol
    1. Position patient so that ear to be operated on is close to the edge of the bed
    2. Gel donut for head
    3. Three straps for foam to strap the patient down to the table.
    4. 180 degrees from anesthesia.
    5. Position the blood pressure cuff on the non-operative side.
    6. Test balance microscope.
    7. Test roll patient
    8. Square off with towels on inferior, superior and lateral aspects then drape towel from Mayo stand to medial face
    9. Place 1030 or "medium" aperture drape from lateral face to Mayo stand
    10. Split drape
  8. Drains and Dressings
    1. No drains
    2. gauze for "packing" EAC
  9. ANESTHESIA CONSIDERATIONS
    1. Consider facial nerve monitoring. Inform anesthesia not to paralyze.
    2. Sometimes performed under local/MAC
  10. OPERATIVE PROCEDURE
    1. The patient will be endotracheally intubated by anesthesia with the tube placed out of the contralateral oral commissure.  NIMS electrodes are possibly used for this procedure ie. if under GA.
    2. Place a speculum in the ear canal. Clear debris from the ear canal and inspect the perforation.
    3. Rim the perforation using a combination of a Rosen needle and Drum Scraper.
      1. To do so, poke the Rosen needle into the TM at the edge of the perforation and elevate a small rim of TM using a back and forth sweeping motion – do this completely around the perforation if possible. Use a small cup forcep to bite any edge of the perforation not made raw by the poking and sweeping of the Rosen needle. Rough up the under surface of the TM around the perforation using the Drum Scraper. (Note: can do before prep or later before raising the tympanomeatal flap)
        1. This effectively disrupts the edges where the outer squamous layer has made contact with the inner mucosal layer to allow for integration of the graft.
    4. In the pediatric population, inject the canal with no more than 0.8 mL of 1:50,000 epinephrine.
      1. Place the ear speculum in the canal and causing the canal skin to pooch at the bony cartilagenous junction. Inject the canal skin subcutaneously at the 12 o’clock, 3 o'clock, 6 o’clock and 9 o’clock positions just proximal to the bony cartilagenous junction.  Inject slowly and watch for a blanch of the canal skin, stop the injection and move to another spot if a bleb is raised. The key to a successful surgery is adequate injection.
    5. Inject 0.5% lidocaine w/ 1:200,000 epinephrine into pre-auricular area and incisura.
    6. Prep the patient, square out the field with green towels stapled to themselves (helpful to place horizontal drape at lateral canthus of the ipsilateral eye and vertical drape along infratemporal line) and then place a ten ten drape over the face and towels
    7. Finger dissect the tissue overlying the temporalis and its fascia.
    8. Inject sterile saline into the temporalis fascia to hydrodissect it. Incise the fascia inferiorly using an 15 blade scalpel and then dissect superiorly both anteriorly and posteriorly using a small scissors (stevens) to widely undermine and separate the fascia from the muscle. (Army-Navy's are good to help retract the tissue superiorly to facilitate harvest). Place the graft in the fascia press x 5 min and then open the press to air.
    9. Palpate the ossicles (ensure mobility), and shape the graft to fit the perforation. Cut the graft to suit the size. A notch may be made in the graft if the perforation goes around the malleus. Slide in the graft, and use a duckbill elevator to help elevate the TM flap. Ensure proper position by regularly folding your flap and TM forward to look at the undersurface of the perforation, then pulling the flap and TM back into their native position and looking at the TM perforation through the hole / releasing incision you’ve made in the canal skin.
    10. Place gelfoam into the ME space to help lateralize the graft. The graft will fail if it's not against the edges of the perforation all the way around (special attention should be paid to anterior superior portion). There should be enough Gelfoam present that the graft slightly bulges out towards the EAC. Tip: use the duckbill to push Gelfoam anteriorly/into place while placing it with the right hand.
    11. Turn back the TM flap, examine the placement through the releasing incision in the canal skin, gently place Gelfoam on top of the graft (EAC side) to ensure placement. Fill the EAC canal with Gelfoam, and turn back the ear. Fill the EAC with Gelfoam.
    12. Close the incision (4-0 vicryl, 5-0 fast-absorbing gut).
    13. Mastoid dressing
  11. POST OPERATIVE CARE
    1. Bacitracin or vaseline covering for gauze - otherwise strict dry ear precautions
    2. Floxin otic 4 drops BID to start immediately after packing removed at one week appointment
    3. Consider postop abx while pack in place
    4. Pain medication 
    5. Audiogram 2-3 months

      Repaired tympanic membrane

      There are no images attached to this page.
       
  12. SUGGESTED READING
    Endaural tympanoplasty without flap. A report on 34 cases. The Journal of Laryngology & Otology / Volume 85 / Issue 06 / June 1971, pp 541 565
  13. DICTATION TEMPLATE
    After informed consent was reviewed, the patient was brought back to the operating room by Anesthesia and placed in a supine position. He was intubated and the table was turned 180 degrees. The operating microscope was brought in, and the left ear canal, following a timeout procedure, verifying the correct site and procedure, was cleaned of cerumen. A 30% anterior inferior perforation was visualized. The perforation included the annulus anteriorly. The decision was reached to perform an endaural approach with canal plasty and temporalis fascia graft. The perforation was prepared at the inferior aspect only, given that the perforation abutted the malleus posteriorly and was completely to the annulus anteriorly. A Rosen needle was used to postage stamp the inferior border and a cup forceps was used to remove this prepared edge. Canal injections using 1:50,000 epinephrine were performed at the 12, 3, 6, and 9 o'clock positions with 0.8 mL total injected. The face and ear were then prepped and draped in a sterile fashion including placement of NIMS facial nerve integrity monitoring probes at the orbicularis oris and oculi. These probes were verified to be in good functioning order. Once again, the operating microscope was brought in, and the initial canal cut using a round knife at approximately 5 mm lateral to the anterior tympanic annulus was performed just over the anterior hump from approximately the 6 o'clock to the 12 o'clock position. A further canal cut was performed using a Beaver blade intersecting the initial cut, however, running straight lateral towards the incisura of the auricle just posterior to the tragal cartilage. A 15-blade was then used to continue this incision out of the ear and on to the preauricular area through the incisura of that ear. A Lempert endaural speculum was placed to provide traction and contertraction in the EAC while the incision was carried down to the bone overlying the zygomatic root. With a Freer elevator, the elevation was performed in a subperiosteal plane using the modified Richard's self-retaining retractors. With these self-retaining retractors in place, an excellent view of the anterior canal and the zygomatic root was obtained. The Freer elevator was used to further elevate the canal flap skin farther medially until we reached our initial canal cut that was parallel to the tympanic membrane. A Bien drill using a 2 mm diamond burr was then brought in, and the anterior hump and portions of the more lateral canal were drilled, providing excellent view of the tympanic membrane. The external auditory canal was then irrigated with normal saline. The temporalis fascia graft was then harvested at the portion of the temporalis fascia just superior to the zygomatic arch through our initial preauricular incision. A Stevens scissors was used to dissect down to the level of the temporalis fascia and a 1.5 x 2 cm fascia graft was harvested. This was handed off for placement into the fascia graft press for 5 minutes. Attention was then redirected to the medial portion of the tympanomeatal flap. A flap knife and 22 suction was used to carefully elevate in a subperiosteal plane until the middle ear was entered at approximately the 11 o'clock position. At this point, a Rosen needle was used to carefully lyse the attached middle ear mucosa from the tympanic annulus. This was carried out from the 12 o'clock to the 6 o'clock position, effectively allowing reflection of the annulus posteriorly. The tympanic membrane was likewise elevated off of the handle of the malleus very carefully using a Rosen needle. The temporalis fascia graft was then brought back in following placement of Gelfoam soaked in ofloxacin into the middle ear space to provide medial support for the graft. The graft was placed following a central cut in the graft to allow manipulation around the handle of the malleus. The graft was maneuvered into place posterior to the handle of the malleus, as well as anterior to the handle of the malleus with a portion effectively underlying the umbo. The initial perforation was completely remedied in this fashion. The tympanomeatal flap was then sectioned at approximately the 11 o'clock position, and both segments laid down over top of the graft. The small segments of Gelfoam were then placed in the external auditory canal on top of the graft and flap. A few interrupted deep stitches were placed in the preauricular tissues around the incisura of the auricle using a 4-0 Vicryl. The remainder of the skin incision was closed using 5-0 fast absorbing gut in interrupted fashion. The external auditory canal was then lightly packed using bacitracin-soaked half inch Nu Gauze. Dermabond was then applied to the facial incision. The patient was turned back to Anesthesia in stable condition, having tolerated the procedure well.