Subtemporalis Muscle Middle Cranial Fossa Bone-Island Craniotomy Technique for Placement of an Active Transcutaneous Bone-Conduction Implant

Abstract

Objective Placement of an active transcutaneous bone-conduction implant (BCI) requires drilling of a precise bone bed to accommodate the device and allow for fixation points to make appropriate contact with bone, which can be difficult even when lifts are used. We describe a subtemporalis muscle middle cranial fossa bone-island craniotomy technique that simplifies the procedure and obviates the need for lifts in securing the device. Study Design Prospective case series. Setting Tertiary academic medical center. Patients Seventeen patients underwent surgery for placement of 18 transcutaneous BCIs, 14 for conductive or mixed hearing loss, and 4 for single-sided deafness. Interventions Surgical placement of a transcutaneous BCI with a bone-island craniotomy technique. Main Outcome Measures Functional gain in air-conduction thresholds, aided air-bone gap, frequency of need for lifts, and minor and major complications. Results For the conductive or mixed hearing loss cohort, with the transcutaneous BCI in place, there was a highly statistically significant mean functional gain of 35.4 dB hearing level (HL) (range, 16.7–50.25 dB HL; standard deviation, 12.4 dB HL) compared with the unaided condition ( p < 0.0001; 95% confidence interval, 36.6–51.6 dB HL). Lifts were not needed in any case. There was one minor complication requiring a second procedure in a patient who had previously received radiation and no major complications. There was no device loss or failure. Conclusions A subtemporalis muscle middle cranial fossa bone-island craniotomy technique eliminates the need for lifts and is a safe and effective method for placement of a transcutaneous BCI.