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Pediatric Post Auricular Tympanoplasty

last modified on: Fri, 04/05/2019 - 11:24

  1. GENERAL CONSIDERATIONS
    1. Indications:
      1. Conductive hearing loss due to perforation or ossicular dysfunction
      2. Chronic or recurrent OM secondary to contamination
      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. 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
      11. Chondritis
  2. PREOPERATIVE PREPARATIONS
    1. Consent - including discussion of post-auricular incision, risks, alternatives & benefits
    2. Other Considerations:
      1. Calculate maximum safe dose lidocaine
      2. Most recent audiogram
      3. 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
      4. 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.
  3. NURSING CONSIDERATIONS
    1. Room Setup
      1. Hang consent, H&P and most recent audiogram on wall.
    2. Instrumentation and Equipment
      1. Leica/Zeiss Operative microscope
      2. Bishop-Harmon irrigation set
      3. Dr. Smiths ear tray
      4. Freimuth currette tray
      5. Ear basic tray
      6. Myringotomy tray
      7. Cartilage microtome tray
      8. Malis bipolar tray
      9. Gelfoam
      10. Clear sticky drape (Incise drape) or 1010 drape
      11. Mastoid tray
  4. Medications (specific to nursing)
    1. 0.5% lido w/ epi (1:200,000); 1% w/ 1:100,000 if >12y
    2. epinephrine (1:50,000); 1:20,000 if >12y
  5. Prep and Drape
    1. Test balance microscope.
    2. Position patient so that ear to be operated on is close to the edge of the bed
    3. Reston for the head, with either a bump from the Rest-on, or a roll of towels to stabilize the head.
    4. Three straps for foam to strap the patient down to the table. Tape the head to the table, long tape that goes across the head with “tape against tape” over the hair area to prevent it from sticking.
    5. Turn 180 degrees.
    6. Rolled green towel tubed under the cheek on the non-operative side.
    7. Drape with squaring off and then use a large occlusive--non-iodine clear sticky drape ("Incise" drape)
    8. Position the blood pressure cuff on the non-operative side.
    9. Test roll patient
  6. Drains and Dressings
    1. No drains
    2. Mastoid dressing
  7. Special Considerations
    1.  
  8. ANESTHESIA CONSIDERATIONS
    1. No facial nerve monitoring. Inform anesthesia not to paralyze.
  9. OPERATIVE PROCEDURE
    1. The patient will be endotracheally intubated by anesthesia with the tube placed out of the contralateral oral commissure.  NIMS electrodes are not used for this procedure. The head should be placed on rest-on foam and the arms tucked or papoosed.
    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 cartilaginous 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 cartilaginous 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 subcutaneously into the post auricular crease.
    6. Prep the patient, square out the field with 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 incise drape over the face and towels
    7. Retract the ear forward and make a C shaped incision through the epidermis using a 15 blade. Carry the dissection down to the temporalis fascia with monopolar cautery, use 2-prong skin hooks to help. You can use your finger to gently sweep the tissue away to find the plane (just above the) temporalis fascia. Inferior limit of the incision should be the the mastoid tip; superiorly limit needs to allow for elevation to the zygomatic root. Identify the base of the temporalis at the temporal line.
    8. Finger dissect the tissue overlying the temporalis and its fascia.
    9. 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.
    10. Make an incision down to the bone using monopolar cautery in the post-auricular sub-cutaneous tissue in the shape of a seven with the horizontal/superior arm of the seven coursing posteriorly about 2cm from the upper border of the ear canal (the superior border of the ear canal should be at the temporal line or at the level of the lateral canthus) and the vertical arm of the seven coursing inferiorly about 2.5cm.
    11. Holding the Lempert elevator 90 deg to the bone, using the thumb of the opposite hand to push blade, forward raising the subcutaneous tissue and periosteum off of the bone forward until the lateral portion of the ear canal is uncovered.
    12. Suction should be switched at this point to an 18 gauge. As you get past the Spine of Henle, consider switching to the microscope. Must identify spine, cribriform area before going forward.
    13. Holding the ear forward with your thumb posteriorly and your forefinger in the concha cymba (do not place the self retaining retractor yet – you’ll put too much tension on the canal skin at this point and potentially tear it) take a canal skin elevator (Shambaugh) and elevate the canal skin from 6 to 12 o’clock in a broad plane until you are at least 0.5 cm deep to the bony ledge of the posterior bony canal. Switch to the duck bill elevator or the McCabe or a round knife and continue to elevate the canal skin toward the annulus. Do not enter the middle ear.
    14. Using an 11 blade scalpel make a releasing incision in the canal skin about 2 mm deep to the level of the bony ledge of the mastoid. This incision should start horizontally and then extend outward to make an H at the inferior and superior limits. Now place the self retaining retractor.
    15. Looking through your releasing / relaxing incision with a speculum, freshen the edges of the perforation by using a Rosen needle to perforate the TM just adjacent to the perforation then sweeping and enlarging the new hole along the perforation edge to raise a rim of TM adjacent to the perforation. Do this on two sides of the perforation. Do not remove large pieces of tympanosclerosis. Use a Hough drum scraper (sometimes called a "Huff Ho") to scrape the bottom of the TM surrounding the perforation in order to cause it to bleed and allow a graft to stick to it. Remember to rotate the table (often towards you while elevating the EAC) to allow for visualization. Keep rotating the table until you can see the entire edges of the perforation (or move the microscope).
    16. Turn your attention back to the medial canal skin, expose the annulus by raising the canal skin to the level of the annulus from 6 o’clock to 12 o’clock using the canal skin elevator, the duckbill or the McCabe. Then, switch to a Rosen or Turner needle to lift the annulus out of its bony groove and enter the middle ear space. Very important – always stay on bone to be safe, the canal bone falls away from you like the ledge of a quarry as you enter the middle ear so if you stay on the bone you will avoid ripping your flap or the TM . Once you have elevated the canal skin, the annulus and some of the middle ear mucosa, proceed by poking through the middle ear mucosa in a safe place (usually inferiorly as you’ll avoid the chorda and the ossicles) to open into the middle cavity.
    17. Once you’ve entered the middle ear space and begun lifting the annulus out of its groove with a needle switch to a Gimmick and swing it back and forth to lift the annulus out of its groove from 6 o’clock to about 11 o’clock. DO NOT AVULSE THE CHORDA, BE COGNIZANT OF ITS POSITION, DO NOT BANG INTO THE MALLEUS OR STAPES, BE COGNIZANT OF THEIR POSITIONS. The TM flap at this point should be draped forward, and out of your way.
    18. 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.
    19. 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.
    20. 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.
    21. Close the incision (4-0 vicryl, 5-0 fast-absorbing gut). Place a mastoid dressing.
  10. VARIATIONS OF TECHNIQUE
    1. If there is no anterior lip of TM present, the "bucket handle" modification may be used. This entails creating an incision in the anterior skin of the canal roughly 2-5mm lateral to the fibrous annulus. A subcutaneous/subannular tunnel is created whereby the meatal skin and fibrous annulus are elevated and the middle ear is entered.
    2. The fascia graft is then modified such that a small flange is cut into its anterior lip. A 6.0 Nylon suture is then sewn through this flange to create a handle. This should be air-knotted at a distance from the flange so as not to tear or distort the graft.
    3. The nylon suture handle is then advanced under the posterior tympanomeatal flap, through the middle ear and into the subannular anterior tunnel. The distal end of the suture is grasped at the canal skin incision and lightly pulled through.
    4. The fascia graft is placed as per usual. The suture is then pulled through to bring the anterior graft flange into the subannular tunnel and to adhere the graft to the annular ring. Medial and lateral gelfoam packing is placed.
    5. The suture is cut and removed, taking care not to disturb the graft
  11. POST OPERATIVE CARE
    1. Mastoid dressing for 1-2 days
    2. Floxin otic 4 drops BID to start immediately after removal of mastoid dressing until RTC in 3 weeks
    3. Consider postop abx
    4. Pain medication 
    5. Audiogram 2-3 months

      Repaired tympanic membrane

       
       
  12. SUGGESTED READING
    1.  Grafting techniques. Wehrs RE. Otolaryngol Clin North Am. 1999 Jun;32(3):443-55.
    2. Tympanoplasty in children. Sarkar S, Roychoudhury A, Roychaudhuri BK.  Eur Arch Otorhinolaryngol. 2009 May;266(5):627-33. Epub 2009 Jan 22.
  13. DICTATION TEMPLATE