Reduction in recurrent cholesteatoma rates with bony obliteration tympanoplasty technique
Reviewed by Aileen Lambert

This large retrospective study from the Erasmus Medical Centre in Rotterdam compares outcomes in traditional canal wall up (CWU) and canal wall down (CWD +/- partial obliteration of mastoid bowl) mastoid surgery for cholesteatoma with bony obliteration tympanoplasty (BOT, which they describe as using harvested bone chips and bone dust to obliterate the mastoid and epitympanum in a CWU mastoidectomy). The study includes 337 mastoid cases in a six-year period, with 62% BOT technique, 24% CWU and 14 CWD overall. One third of cases involved primary surgery. There is acknowledged indication bias in terms of choosing which technique to use based on size/pneumatisation etc. The main rationale behind the BOT technique that they cite is separation of epitympanum and mastoid from the middle ear prevents recurrent cholesteatoma as there is no space to retract into, and may reduce middle ear gas pressure changes, as well as creating an unfavourable environment for cholesteatoma growth. The median follow-up time was 31 months (range 16-51 months), and DW MRI was planned at one and five years post surgery. The main finding of the study is that the total recurrence rate at five years (including residual cholesteatoma) in the BOT group was 7.6% compared with 32.9% in the CWU group, which showed a significant statistical difference (p=0.001) and 17.9% in the CWD group (not significant). The recurrence rate in BOT was plotted as reducing over the time the technique was introduced, in line with an expected learning curve. The STAM and EAONO/JOS classifications were used to compare outcomes in terms of extent of cholesteatoma, and the reduction was still seen even for small cholesteatomas. This study also looked at hearing outcomes and they did find a statistically significant improvement in median threshold air conduction hearing levels in the CWU group, compared with both BOT and CWD. However, in real terms, that improvement was only 3.8 dB. There were similar levels of postoperative infection in each group but higher levels of temporary facial palsy postoperatively (n=4) in the BOT group, all of which resolved with steroids and no definite cause found to indicate why there were more in this group. Bony obliteration tympanoplasty certainly appears to represent a useful technique to improve outcomes in cholesteatoma surgery in appropriate cases.

Treatment Outcome of the Bony Obliteration Tympanoplasty Versus Nonobliterative Techniques in Cholesteatoma Surgery: A Retrospective Analysis.
Van der Toom H, Van der Schroeff P, Metselaar M, et al.
OTOL NEUROTOL
2021;42(9):1366-74.