Well drilling vs. subperiosteal pocket for cochlear implants – comparison of operative time, complications and cost-effectiveness
Reviewed by Aileen Lambert

The choice of method for securing the receiver/stimulator (R/S) package during cochlear implant surgery is usually dependant on several factors, but primarily surgeon preference. The initial recommendation from manufacturers was to drill a bony well (WD technique) and use bony tie-down sutures. Over the last decade there has been a move to the less time-consuming tight subperiosteal pocket technique (SPT), which also has less risk of intracranial complications. This study makes reference to the lack of high-quality evidence for determining which method is superior, in particular a lack of randomised controlled trials (RTC). This study from New York is also not an RCT but it is a retrospective study looking at whether there is a long-term cost benefit of either method, with follow-up periods of between 32 (WD) and 47 (SPT) months post-implantation. The cost-effectiveness analysis was undertaken using the incremental cost-effective ratio (ICER) (difference in cost between SPT and WD, divided by the difference in their outcomes/complications) and the ‘willingness to pay’, a measure of the extra costs a patient would pay for a health benefit/to avoid a major complication. The study includes 388 cochlear implant procedures (179 WD/209 SPT) in one hospital with 10 different surgeons over an eight-year period. The often-cited operative time reduction using the subperiosteal pocket technique was 12% (approx. 20 minutes), less than in other publications (up to 30% time reduction cited). Likewise, this study deviated from the existing literature in finding that the SPT group had higher rates of major postoperative complications, i.e., device failure/skin-related complications, but this was not statistically significant when considering confounding factors. The authors acknowledge the difficulty in attributing complications to type of technique for securing the R/S package alone. The cost-effectiveness results found that the slightly costlier WD technique has lower major complications, so it had an overall marginal cost benefit. However, the authors used modelling with small changes either way in their cost analysis to demonstrate that actually there is no convincing difference in the cost-effectiveness of either technique based on their data. Until more robust data from RCTs is available, it would appear from this paper that the choice of technique for securing a cochlear implant R/S package remains equivocal.

Comparison of cochlear implant device fixation—well drilling versus subperiosteal pocket. A cost effectiveness, case–control study.
Shavit S, Weinstein E, Drusin M, et al.
OTOLOGY AND NEUROTOLOGY
2021;42(4):517-23.