Reduction in high-frequency hearing loss following technical modifications to microvascular decompression for hemifacial spasm

Abstract

M icrovascular decompression (MVD) is a safe and efficacious procedure for the treatment of hemifacial spasm (HFS), a debilitating condition that reduces patients' quality of life. Severe sensorineural hearing loss (SNHL) across all frequencies is a known complication of the operation, with reported rates ranging from 1.4% to 20%. 4,12,[18][19][20][21]24 In addition to severe SNHL, however, a recent report has raised concern that as many as one-half of patients undergoing MVD for HFS may experience high-frequency (4-8 kHz) hearing loss.28 Although this type of hearing loss is not as obviously apparent upon clinical follow-up as severe SNHL, high-frequency hearing loss (HFHL) can profoundly reduce the quality of life of patients. 5,10 Although the prior report implicated noise from the high-speed surgical drill as the cause of HFHL following MVD, we conducted this study to examine the incidence of HFHL, with an emphasis on retractorless MVD for treatment of HFS.abbreviatioNs BAEP = brainstem auditory evoked potential; HFHL = high-frequency hearing loss; HFS = hemifacial spasm; MVD = microvascular decompression; SNHL = sensorineural hearing loss; SPL = sound pressure level. obJect Microvascular decompression is a safe and effective procedure to treat hemifacial spasm, but the operation poses some risk to the patient's hearing. While severe sensorineural hearing loss across all frequencies occurs at a low rate in experienced hands, a recent study suggests that as many as one-half of patients who undergo this procedure may experience ipsilateral high-frequency hearing loss (HFHL), and as many as one-quarter may experience contralateral HFHL. While it has been suggested that drill-related noise may account for this finding, this study was designed to examine the effect of a number of techniques designed to protect the vestibulocochlear nerve from operative manipulation on the incidence of HFHL. methods Pure-tone audiometry was performed both preoperatively and postoperatively on 67 patients who underwent microvascular decompression for hemifacial spasm during the study period. A change of greater than 10 dB at either 4 kHz or 8 kHz was considered to be HFHL. Additionally, the authors analyzed intraoperative brainstem auditory evoked potentials from this patient cohort. results The incidence of ipsilateral HFHL in this cohort was 7.4%, while the incidence of contralateral HFHL was 4.5%. One patient (1.5%; also included in the HFHL group) experienced an ipsilateral nonserviceable hearing loss. coNclusioNs The reduced incidence of HFHL in this study suggests that technical modifications including performing the procedure without the use of fixed retraction may greatly reduce, but not eliminate, the occurrence of HFHL following microvascular decompression for hemifacial spasm.

Bioglue-Coated Teflon Sling Technique in Microvascular Decompression for Hemifacial Spasm Involving the Vertebral Artery

“…Intermittent release of the retractor, based on the intraoperative BAEP monitoring, would also help to prevent possible hearing loss 25) . Some authors have suggested that performing the procedure without the use of fixed retraction may help reduce hearing loss 38) . We have also performed MVD surgery using a retractor, and particularly when the VA is the causative offending vessel, intermittent retraction on the cerebellum was needed to prevent the development of hearing loss.…”

An investigation into quality of life improvement in patients undergoing microvascular decompression for hemifacial spasm

“…Neurosurgeons have attempted to lower these risks by using techniques such as brainstem auditory evoked potentials to minimize damage. 78 Despite these efforts, a risk of permanent cranial nerve damage remains.…”

Risultati chirurgici a lungo termine della decompressione microvascolare nell’emispasmo facciale: efficacia, morbilità e qualità di vita

“…Retraction of the cerebellum by a spatula could be the major cause of surgical complications. In our study, the surgical procedure without the use of fixed retraction may greatly reduce the occurrence of SNHL following MVD for HFS 18 19 . Fixed retraction of the cerebellum with selfretaining retractor was never used during any step of the procedure in our institution since the beginning of our use of the minimal invasive retrosigmoid approach 9 .…”