Background: In some rare cases of congenital aplasia of the oval window (OW), malformed facial nerve (FN) locations covering the most or entire OW present a challenge to hearing reconstruction, there is no a highly effective surgical hearing reconstruction methods.
Aims/objectives: To update a Scala tympani drill-out technique (SDT) for abnormal FN course covering the OW.
Material and methods: All patients of congenital atresia of the OW was recruited between August 2014 and July 2023 in a tertiary-care center. When it's inability to perform the vestibulotomy with FN covering the OW, The SDT surgery was made with a titanium TORP between the tympanic membrane and scala tympani fenestration for hearing reconstruction. Air conduction (AC) thresholds, bone conduction (BC) thresholds, and air-bone gap (ABG) at 0.5, 1, 2, 4 kHz pure tone frequencies were compared before and 3 months after surgery.
Results: A total of 11 patients underwent SDT surgery during the study period. All cases showed no bone conduction (BC) hearing loss, facial paralysis, tinnitus, or dizziness. The ABG has decreased by 21.2 ± 10.8 dB 3 month after operation. In the long term, three cases had the same hearing as pre-operative, three cases felt their hearing gradually decreased but better than pre-operative.
Conclusions and significance: As a new and optional method, our results suggest an effective way to reconstruct hearing for middle ear deformities with FN occlusion, the short-term effect can be confirmed, while the long-term effect is mixed, and a large amount of clinical research is still needed.
Keywords: Congenital absence of the oval window; middle ear malformation; scala tympanidrill-out.