Thieme: Tympanoplasty, Mastoidectomy, and Stapes Surgery

238 7 Stapedotomy and Stapedectomy

sive frequency of malleus fixation led us to system- Malleo-Stapedotomy atically investigate the condition of the anterior mallear ligament and process in patients presenting Surgical Technique with stapes fixation, particularly of otosclerotic ori- In the first edition of this book, we stated that the gin. elevation of a wide tympanomeatal flap exposing the lateral process of the malleus (see Fig. 109 C) Surgical Highlights permits reliable assessment of mallear mobility at K Local or general anesthesia. the beginning of stapedotomy. Failure to initially ex- K Endaural incision. pose the short process of the malleus has led the K Elevation of meatal skin flap. first surgeon to overlook malleus and/or incus fixa- K Anterosuperior canalplasty. tion in 10 % of the cases (see Table 33). MS (previ- K Exposure of anterior tympanic spine and ously incus replacement with stapedotomy [IRS]) assessment of malleus mobility. was the method of choice for the functional repair K Removal of incus. of malleus and/or incus fixation in otosclerosis. K Drilling away ossified anterior mallear liga- In the past 10 years it became apparent that the ment and removal of malleus head, preserva- anterior mallear ligament may undergo severe hya- tion of chorda tympani nerve. linization and ossification in 30 % of otosclerotic pa- K Introduction of TSP (straight or angled) be- tients (Nandapalan et al. 2002, 18-R). The increasing tween malleus handle and stapes footplate. stiffness of the anterior mallear ligament produces K Stapedotomy with manual perforators. a partial fixation of the malleus with impairment of K Removal of stapes arch with crurotomy scis- sound transmission in frequencies above 1000 Hz sors. (Huber et al. 2003, 9-R). The analysis of 80 patients K Introduction of piston into vestibule. undergoing revision surgery after stapes surgery K Fixation of titanium loop to malleus handle. demonstrated that partial malleus fixation was K Sealing of stapedotomy opening. present in 37 % (Fisch et al. 2001, 3-R). The impres-

Fig. 118 Anterior malleolar Typical sites of malleus and/or incus ligament fixation in otosclerosis Malleus head The most common mallear fixation oc- curs through ossification of the anteri- Incus body or mallear ligament (1). Hyalinization and ossification of the anterior mallear ligament are related to the duration of the otosclerotic fixation and independ- ent of the age and gender of the pa- tient. Fixation of the malleus head (2) and incus body (3) are usually found in narrow external canals.

Surgical Steps Modifications: The tympanomeatal flap has become The surgical steps will be demonstrated for the Te- much larger anterosuperiorly to give sufficient view flon platinum prosthesis used until 1996. The modi- of the anterior mallear process and ligament. fications which have occurred since its introduction will be noted in italics.

Fig. 119 A1 Assessment of mallear mobility A1 The narrow external canal is widened as shown in Figures 108 A, B. The tympanomeatal flap is then elevated over the lateral process of the malleus (see Fig. 107 G). Palpation with a 1.5-mm, 45° hook shows that the malleus is fixed.

D A E Fig. 119 A2 2 Incisions for the meatal part of the tympano meatal flap A Endaural incision (A–B); posterior limb of meatal in- B cision (B–C); anterior limb of meatal skin incision (B–D). The narrow external canal prevents visualiza- tion of the malleus handle. This is often the case in partial or total malleus fixation.

Fig. 119 A3 Anterosuperior canalplasty A3 The skin of the tympanomeatal flap is elevated Anterior tympanic from the tympanosquamous suture and the sur- spine rounding bone with the Fisch microraspatory (23-I, 24-I). The anterosuperior excess bone is removed B2 D until the anterior tympanic spine becomes visible. A The tympanic portion of the tympanomeatal flap remains attached to the bone until completion of the canalplasty to avoid contamination of the mid- B1 dle ear while rinsing with saline during drilling.

Posterior tympanic spine