Tinnitus: an underreported condition following microvascular decompression for hemifacial spasm

PURPOSE

While hearing loss is a well-known condition following microvascular decompression (MVD) for hemifacial spasm (HFS), tinnitus is an underreported one. This study aims to identify prevalence, characteristics, severity, and predictors of tinnitus following MVD for HFS.

METHODS

A single-center cohort of 55 HFS patients completed a questionnaire approximately 5 years following MVD. Data encompassed tinnitus presence, side, type, onset, and severity measured by a 10-point Visual Analogue Scale (VAS). Descriptive, correlation, and logistic regression analyses were conducted. RESULTS  : At surgery, participants' median age was 58 years (IQR 52-65). The median duration of HFS symptoms before surgery was 5 years (IQR 3-8), slightly predominant on the left (60%). Postoperative tinnitus was reported by 20 patients (36%), versus nine (16%) that reported preoperative tinnitus. Postoperative tinnitus was ipsilateral on the surgical side in 13 patients (65%), bilateral in six (30%), and contralateral in one (5%). Among patients with bilateral postoperative tinnitus, 33% did not have this preoperatively. Tinnitus was continuous in 70% of cases and pulsatile in 30%. Onset of new tinnitus was in 58% immediately or within days, in 25% within three months, and in 17% between three months and one year after surgery. The mean severity of postoperative tinnitus was 5.1 points on the VAS. Preoperative tinnitus and presence of arachnoid adhesions had suggestive associations with postoperative tinnitus in initial analyses (p = 0.005 and p = 0.065). However, preoperative tinnitus was the only significant predictor of postoperative tinnitus (p = 0.011).

CONCLUSION

Tinnitus is a common condition following MVD for HFS, with a moderate overall severity. Causes behind postoperative tinnitus remain obscure but could be related to those of postoperative hearing loss in this patient population. Clinicians should be aware of tinnitus following MVD and vigilantly monitor its occurrence, to facilitate prevention efforts and optimize outcome for HFS patients undergoing MVD.

Potential reasons for failure and recurrence in microvascular decompression for hemifacial spasm

BACKGROUND

To examine the factors contributing to persistent and recurrent hemifacial spasms (HFS) following a microvascular decompression (MVD) procedure and to suggest technical improvements to prevent such failures.

METHODS

A retrospective review was conducted on fifty-two cases of repeat surgery. The extent of the previous craniotomy and the location of neurovascular compression (NVC) were investigated. The operative findings were categorized into two groups: "Missing Compression" and "Teflon Contact". The analysis included long-term outcomes and operative complications after repeat MVD procedures.

RESULTS

Missing compression was identified in 29 patients (56%), while Teflon contact was observed in 23 patients (44%). Patients with missing compression were more likely to experience improper craniotomy (66%) compared to those with Teflon contact (48%). Medially located NVC was a frequent finding in both groups, mainly due to compression by the anterior inferior cerebellar artery. In the missing compression group, during the repeat MVD, Teflon sling retraction was utilized in 79% of cases, while in the Teflon contact group, the most common procedure involved removing the Teflon in contact (65%). After the repeat MVD procedure, immediate spasm relief was achieved in 42 patients (81%), with six (12%) experiencing delayed relief. After a median follow-up of 54 months, 96% of patients were free from spasms. Delayed facial palsy, facial weakness, and hearing impairment were more frequently observed in the Teflon contact group.

CONCLUSIONS

A proper craniotomy that provides adequate exposure around the REZ is crucial to prevent missing the culprit vessel during the initial MVD procedure. Teflon contact on the REZ should be avoided, as it poses a potential risk of procedure failure and recurrence.

Vestibulocochlear Symptoms Caused by Vertebrobasilar Dolichoectasia

OBJECTIVES

Vertebrobasilar dolichoectasia (VBD), an elongation and distension of vertebrobasilar artery, may present with cranial nerve symptoms due to nerve root compression. The objectives of this study are to summarize vestibulocochlear manifestations in subjects with VBD through a case series and to discuss the needs of thorough oto-neurotologic evaluation in VBD subjects before selecting treatment modalities.

METHODS

Four VBD subjects with vestibulocochlear manifestations were reviewed retrospectively. VBD was confirmed by either brain or internal auditory canal magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). Patient information, medical history, MRI/MRA findings, and audiometry or vestibular function tests were reviewed according to patient's specific symptom.

RESULTS

Of the four subjects, three presented with ipsilesional sensorineural hearing loss (SNHL), three with paroxysmal recurrent vertigo, and two with typewriter tinnitus. The MRI/MRA of the four subjects revealed unilateral VBD with neurovascular compression of cisternal segment or the brainstem causing displacement, angulation, or deformity of the cranial nerve VII or VIII that corresponded to the symptoms.

CONCLUSION

Vestibulocochlear symptoms such as SNHL, recurrent paroxysmal vertigo, or typewriter tinnitus can be precipitated from a neurovascular compression of the vestibulocochlear nerve by VBD. Because proper medical or surgical treatments may stop the disease progression or improve audio-vestibular symptoms in subjects with VBD, a high index of suspicion and meticulous radiologic evaluation are needed when vestibulocochlear symptoms are not otherwise explainable, and if VBD is confirmed to cause audiovestibular manifestation, a thorough oto-neurotologic evaluation should be performed before initial treatment.

Microvascular Decompression for Trigeminal Neuralgia: A Durable, Noncompressive Technique Using Teflon Secured With Mini Clip

BACKGROUND

In cases of trigeminal neuralgia, the importance of durable separation of involved vessels from the trigeminal nerve as well as avoiding ongoing or recurrent compression by implanted material has been affirmed in recent literature.

OBJECTIVE

To demonstrate a novel and straightforward technique for trigeminal nerve decompression using a construct of Teflon felt patty (Bard Peripheral Vascular, Tempe, Arizona) secured with an aneurysm mini clip to achieve lasting results with no residual contact between implant or vessels and the nerve.

METHODS

Description of our technique and accompanying surgical video.

RESULTS

As demonstrated in the video, this technique achieves an ideal, durable separation of the trigeminal nerve from the offending vasculature.

CONCLUSION

The authors present a description of a technique for decompression with the goal of leaving no contact between implanted material and the nerve. This is accomplished by securing the Teflon felt (Bard Peripheral Vascular) to the tentorium with an aneurysm clip.