Specific Aspects of Outcome after Transtemporal Acoustic Neuroma Surgery

Introduction: Transtemporal acoustic neuroma surgery aims at tumor removal with hearing preservation. It is still a question of debate whether the postoperative preserved hearing is stable or if it will deteriorate after surgery. Furthermore, for adequate exposure of the internal auditory canal, in order to achieve tumor resection with hearing preservation, a certain retraction of the temporal lobe is necessary, with the risk of causing a cerebral injury by the pressure on the vessels and the brain tissue itself.

Material and Methods: Out of a series of 1300 transtemporal acoustic neuroma resections (extended approach to Wigand) sufficient audiometric measurements to evaluate long-term auditory function (1.5 to 10 years after surgery) was available in 222 patients. In 33 patients magnetic resonance imaging was available for analysis for temporal lobe gliosis 1 year after surgery.

Results: Our pure tone and speech discrimination analysis proved a stable long-term hearing preservation after transtemporal tumor resection in a series of 222 patients. After surgery, a hearing loss ranging from 10 to 15 dB was found. In the long-term follow-up only slight additional hearing losses were observed and judged to represent slight hearing loss related to aging. Temporal lobe gliosis was found in 17 out of the analyzed 33 patients 1 year after surgery: it was 13 times discreet, 2 times moderate, and 2 times distinct.

Conclusions: Transtemporal acoustic neuroma surgery provides the opportunity of tumor removal with long-term hearing preservation. It has to be considered that even in cases of an extended transtemporal approach according to Wigand, gliosis of the temporal lobe can occur but will be mainly of discreet extent.