A CASE OF CONGENITAL CHOLESTEATOMA WITH ANTERIOR SEMICIRCULAR CANAL FISTULA
Introduction
Labyrinthine fistula is a severe complication of cholesteatoma. The incidence of labyrinthine fistula is 7% in reported series of mastoidectomies for chronic ear disease.1 It is reported that the prevalence of the anterior semicircular canal fistula is respectively 6% of the labyrinthine fistulae.1,2 We experienced a case of congenital cholesteatoma and the malformation of auditory ossicles with anterior semicircular canal fistula.
Case report
A 15-year-old male had suffered from right hearing loss in childhood. He was diagnosed with right hearing loss at a health-care examination in May 2011. He visited our hospital for further examination.
The right tympanic membrane was intact. Pure-tone audiogram revealed a 38 dB conductive-hearing loss in the right ear (Fig. 1).
Auditory ossicles were detected (Fig. 2A). The attic was filled with soft-tissue density (Fig. 2B). Soft-tissue density existed in the aditus ad antrum and the mastoid antrum. Part of the bone surrounding the anterior semicircular canal was unclear. The anterior semicircular canal fistula was suspected (Fig. 2C and D).
A part of the long process of the incus was incomplete and the incudo-stapedial joint showed fibrous chain (Fig. 3A). The superstructure of the stapes was intact. The cholesteatoma existed widespread from attic to mastoid antrum (Fig. 3B). Then, the cholesteatoma matrix penetrated into the small space of mastoid cells and behind the lateral semicircular canal (Fig. 3C). An anterior semicircular canal fistula was confirmed (Fig. 3D). Based on the CT scan and intra-operative findings, a labyrinthine fistula was classified in six stages (Table 1). The anterior semicircular canal fistula of this case was stage III. The removal of the cholesteatoma matrix might be incomplete behind the lateral semicircular canal and the vicinity of the anterior semicircular canal fistula. Therefore, a planned staged tympanoplasty without ossiculoplasty was performed.
Post-operative vertigo and nystagmus was observed until one month after surgery. The post-operative pure-tone audiogram is shown in Figure 4. Bone-conduction threshold showed a 60 dB hearing loss at 4,000 Hz in the right ear. The patient has been under observation as an outpatient for nine months and has presented no signs of recurrence of cholesteatoma. A second-look operation was planned.
Fig. 1. Pure-tone audiogram revealed a 38dB conductive hearing loss in the right ear.
Fig. 2. Axial section CT. A. The superstructure of the stapes was detected (arrow); B. Attic was filled with soft tissue density (arrow). Coronal and axial section CT. C, D. Part of the bone surrounding the anterior semicircular canal was unclear (arrow). The anterior semicircular canal fistula was suspected.
Discussion
The incidence of a labyrinthine fistula is 7% in a reported series of mastoidectomies for chronic ear disease.1 The location of the labyrinthine fistula was predominantly of the lateral semicircular canal (87%) followed by the promontry (8%), anterior semicircular canal (6%), and posterior semicircular canal (2%).1 The incidence of post-operative sensorineural hearing loss with cholesteatoma matrix removal varies from 6% to 37%.2 Table 2 shows the reported hearing in cases of labyrinthine fistulae since 2000. Fistula stages should theoretically correlate with the risk of sensorineural hearing loss. Much debate has arisen in the literature regarding the treatment of the fistula matrix. The first approach is to leave the matrix on the fistula, while the second approach advocates the total removal of the cholesteatoma from the fistula in one or two stages. Advantages of the matrix removal are the reduction of bone resorption, risk of suppurative labyrinthitis, and post-operative vertigo. The main disadvantage is the potential risk of post-operative sensorineural hearing loss.3 Kobayashi et al. recommended a one-stage, open-method tympanoplasty and emphasized that careful manipulation of the semicircular canal can be conducted without damaging the cochlear function.4 In the present case, the sac of cholesteatoma was not clear. As a result, total removal of cholesteatoma matrix vicinity the anterior semicircular canal fistula caused the sensorineural hearing loss. It is essential that treatment of the labyrinthine fistula is delicate in order to preserve hearing. The choice of surgical technique for a labyrinthine fistula is determined by the patient’s general condition, the ipsi- and contralateral hearing thresholds, and the skill and experience of the surgeon.5
Fig. 3. A. A part of long process of incus was incomplete and incudo-stapedial joint was fibrous chain (arrow). Chorda tympani (arrowhead); B. The cholesteatoma (▴) was open type and existed widespread from attic to mastoid antrum; C. The cholesteatoma matrix (▴) penetrated into the small space of mastoid cells and behind the lateral semicircular canal (⋇). The removal of cholesteatoma matrix might be incomplete behind the lateral semicircular canal; D. Anterior semicircular canal fistula was confirmed (arrow). This case was stage III.
Table 1. Fistula staging.
Stage I: Pre-fistula (blue line) |
Stage II: Small fistula ≤ two mm |
Stage III: Fistula between two and four mm Stage IV: Invasion of one (a) or more (b) semicircular canal(s) |
Stage V: (a) Invasion of vestibule |
(b) Invasion of vestibule and cochlea |
Stage VI: (a) Fistula limited to the stapes footplate |
(b) Promontorial fistula |
Fig. 4. Post-operative pure-tone audiogram. Bone-conduction threshold showed a 60dB hearing loss at 4,000 Hz in the right ear.
Table 2. Reportedhearing in cases of labyrinthine fistulae. Year Pre-operative
References
1.Copeland BJ, Buchman CA. Management of labyrinthine fistulae in chronic ear surgery. Am J Otolaryngol 24(1):51–60, 2003
2.Bergeron M, Saliba I. Canal wall window mastoidectomy for extensive labyrinthine cholesteatoma: total dissection and hearing preservation. Int J Pediatr Otorhinolaryngol 75(7):976–979, 2011
3.Quaranta N, Liuzzi C, Zizzi S, Dicorato A, Quaranta A. Surgical treatment of labyrinthine fistula in cholesteatoma surgery. Otolaryngol Head Neck Surg 140(3):406–411, 2009
4.Kobayashi , Sato T, Toshima M, Ishidoya M, Suetake M, Takasaka T. Treatment of labyrinthine fistula with interruption of the semicircular canals. Arch Otolaryngol Head Neck Surg 121(4):469–475, 1995
5.Ueda Y, Kurita T, Matsuda Y, Ito S, Nakashima T. Surgical treatment of labyrinthine fistula in patients with cholesteatoma. J Laryngol Otol 123(Suppl 31):64–67, 2009
Address for correspondence: Ryo Ikoma, ikoma-r@minamikyousai.jp
Cholesteatoma and Ear Surgery – An Update, pp. 387–390
Edited by Haruo Takahashi
2013 © Kugler Publications, Amsterdam, The Netherlands