Interpretation
Labyrinthine fistula (LF) is a known complication of cholesteatomas, most common in the lateral SCC, but also affects superior SCC in 6% and posterior SCC in 2% of LFs (6). Clinical suspicion of LFs is limited by non-specific symptoms – mostly sensorineural or mixed hearing loss, accompanied by vertigo, otorrhea and otalgia also present in chronic otitis media. Classic clinical signs such as fistula sign may only have a sensitivity of 21.7% to 60% (7), false negative rate of up to 54% (8). Also, there is lack of uniformity in performing the test.
While some centres have used the Dornhoffer and Milewski classification to stage fistulas based on bony defects and size of fistulas to determine surgical method, the fistula size, size and grade have been reported to not correlate with surgical outcomes (9). Surgeon 1’s technique of matrix removal was applied to all LFs, irrespective of size of fistula. Sealing of fistulas included bone wax and temporalis fascia, consistent with literature also reporting the use of bone wax, temporalis fascia, bone dust, tissucol, fibrin glue, Spongiostan and autogenous tissues (6, 9).
Postoperative hearing deterioration rate has been reported in 2.8-26.9% (9), possibly attributed to the removal of cholesteatomas and granulation tissue previously acting as conduits in conducting sound into ear. Postoperative deterioration in sensorineural hearing loss occurs in 23% to 50% that underwent complete matrix removal and 1 to 44% for matrix left in-situ (9). Unlike the review by Lim et al (9), our patients with matrix preservation had poorer hearing outcome, perhaps due to longer follow-up time. Matrix removal, however, had hearing preservation in 78% although 2 ears had initial worsening within 120 days postoperatively. This is in contrary to greater deterioration of long-term hearing outcomes found by Katsura et al (10), despite initial improvements within the first year, postulated to the involvement of third window during the initial recovery stage. Postoperative persistent hearing loss could be a result of inflammatory effects of the remnant cholesteatoma matrix.