Hearing Preservation After Segmental Semicircular Canal Destruction: A Report of Two Rare Cases

Semicircular canal fistulas are a complication of cholesteatomatous otitis media. In extremely rare cases, extensive destruction of the bony labyrinth may result in loss of approximately one-third of the semicircular canal arc, often with wide exposure and partial injury to the membranous labyrinth, thereby increasing the risk of profound sensorineural hearing loss. Complete eradication of the cholesteatoma while preserving inner ear function remains challenging. Here, we report two rare cases of segmental loss of the semicircular canal arc in which useful hearing was retained. Case 1 involved a 64-year-old man, in whom cholesteatoma erosion destroyed a continuous segment of the lateral semicircular canal, effectively eliminating approximately one-third of the ring structure. After complete cholesteatoma removal, the entire defective segment was sealed with perichondrium and thin cartilage, under continuous saline irrigation and supplemented with postoperative steroid therapy. The fistula sign resolved, the bone conduction thresholds remained stable, and conductive hearing improved. Case 2 involved a 45-year-old man who underwent tympanoplasty. The intraoperative anatomical misorientation resulted in the unintended removal of a substantial portion of the posterior semicircular canal ring. Multilayer closure using the cartilage and fascia was performed while carefully preventing dehydration of the exposed membranous labyrinth. Postoperative audiometry showed retention of useful hearing at follow-up in both cases, although Case 2 showed a mild early postoperative decline in bone conduction thresholds. These cases suggest that even in exceedingly rare situations involving segmental semicircular canal loss, prompt and meticulous surgical management may help preserve hearing. Important considerations include underwater dissection, avoidance of direct suction, multilayer cartilage-based reconstruction, and perioperative steroid therapy.