Management of Ossicular Abnormalities

Type 1 Tympanoplasty

Any procedure of the tympanic cavity or middle ear with the conservation of an intact chain and tympanic membrane reconstruction.

Fig. 5.1

Type 2 Tympanoplasty

Any ossiculoplasty involving the stapes with a columella effect from the stapes to the malleus handle or eardrum (intact or reconstructed).

Fig. 5.2

Reconstruction in case of an absent or severely defective stapes. The columella extends from the footplate to the malleus handle or eardrum (intact or reconstructed).

Fig. 5.3

Type 4 Tympanoplasty

Platinotomy for a fixed footplate and no ossicles (except malleus). The eardrum must be intact.

Fig. 5.4

Malleus and Incus Fixation

The incus or malleus can be fixed in the epitympanic region.

Fig. 5.5

Fig. 5.6

Fig. 5.7

Malleus Tendon Cut

If malleus handle movement is still compromised, the malleus tendon may be calcified and should be cut using curved or straight microscissors.

If there is sufficient exposure, the bony fixation of the incus or malleus head can be drilled using a very thin diamond burr. Adequate space should be created between the ossicle and bony wall to avoid recurrence of fixation. A Silastic sheet may be inserted in between.

Fig. 5.8

The stapes may be fixed by tympanosclerotic plaques. The tympanic membrane must be intact to manage stapes immobility. Tympanosclerotic plaques can be carefully removed using a needle or small hook. Stapes mobility can be restored, but refixation frequently occurs. Generally, the superstructure should be removed using a laser or microscissors. The footplate is cleaned of the tympanosclerosis with a needle or small hook, moving parallel to the facial nerve in an anteroposterior direction. Footplate mobility is thus restored and an ossiculoplasty is performed. If the footplate remains fixed, a stapedotomy is performed.

In our experience, a transcanal approach is used in 98 % of all surgical procedures. In the case of a very narrow external auditory canal or second-stage surgery for stapedial tympanosclerosis, however, a retroauricular approach is required.

Stapes Surgery, Head Position

Fig. 5.9

Transcanal Approach

A short nasal speculum is used until work is started on the ossicular chain. The disinfection liquid is aspirated completely and the canal is washed out with water.

Fig. 5.10

The procedure starts with a Rosen incision, a curved incision from 12 o’clock to 6 o’clock.

A lateral incision is first made inferiorly at 6 o’clock, then superiorly at 12 o’clock, using a lateral knife. The superior incision must be at least 8–10 mm long and the inferior incision 6–8 mm.

A circumferential incision joins the lateral incisions in a curve.

Fig. 5.11

Skin Flap Elevation

The skin flap is elevated toward the fibrous annulus using a small, round knife.

Because of the skin thickness, and to preserve smooth edges, it is sometimes necessary to complete the superolateral incision using straight microscissors.

Microsuction is performed with a small cotton ball or piece of Merocel soaked in 1 % lidocaine with 5 µg/mL epinephrine to protect the skin and reduce bleeding.

Fig. 5.12

A needle or sickle knife is inserted between the chordal eminence and short process of malleus, and the tympanic membrane is elevated. Then, using a lateral knife, the fibrous annulus is dislocated out of the sulcus starting at the transition of the chordal eminence, paying special attention to the chorda tympani. The middle ear mucosa must be incised to enter the middle ear cavity. When the opening is large enough, a flap knife or dissector-elevator is inserted and the fibrous annulus is luxated until an adequate view of the malleus neck and the round window is achieved.

Fig. 5.13

Chorda Tympani Dissection

If the chorda tympani compromises access to the stapes and oval window, the nerve must be disinserted from its bony well using a needle or microhook.

Fig. 5.14

The chorda tympani is pushed medially without being stretched

Fig. 5.15

Posterior Tympanoatticotomy

Bony Frame Fracture

Tympanoatticotomy is performed using a 3-mm chisel. The bone is fractured perpendicularly and tangentially to the frame.

Fig. 5.16

The atticotomy is completed with a curette to expose two-thirds of the long process of the incus, the facial nerve above the oval window, the oval window itself, the posterior crus of the stapes, and the stapedial tendon and pyramidal eminence. The curette is applied using posterior and inferior rotation movements.

Fig. 5.17

Placement of a Portmann Retractor

Placement of a Portmann retractor allows a bimanual technique to be used. An adequate view of the structures previously described is vital. To this end, the atticotomy must be sufficiently large, rotation of the patient’s head must be adjusted, and the speculum must be positioned perpendicular to the canal and opened as wide as possible.

Fig. 5.18

Malleus and Incus Mobility Testing

Mobility of the ossicular chain is checked using a needle. The malleus handle is gently pulled up to verify the integrity and mobility of the incudomallear complex.

Fig. 5.19

Malleus or Incus Fixation and Stapes Mobility Testing

Fig. 5.20

Stapedial Tendon Cut

The stapedial tendon is cut with straight microscissors or a diode laser (1.5 W in continuous mode). Section of the tendon exposes the posterior crus.

Fig. 5.21

Posterior Crus Cut

A diode laser is applied to cut the posterior crus in its inferior half. The protruding pyramidal eminence can be drilled using a Skeeter drill (Medtronic Xomed). A diamond or cutting microburr of 0.6–1 mm is utilized. Use of a diamond microburr minimizes bleeding.

Fig. 5.22

The anterior crus is generally hidden by the long process of the incus. Rotation of the patient’s head might facilitate visualization and allow its section using the diode laser. In the majority of cases, the anterior crus is identified by touching it with the laser probe. It is broken blindly.

Fig. 5.23

Stapes Superstructure Removal

Sometimes this step is not possible and the anterior crus is broken up by means of small left-to-right lateral movements of the superstructure with a needle or microhook. When the superstructure feels free, it is pushed onto the promontory to be removed using fine microforceps.

Fig. 5.24

Grade I

Normal appearance of the footplate, but with ligament ankylosis