Utilization of 3D imaging reconstructions and assessment of symptom-free survival after microvascular decompression of the facial nerve in hemifacial spasm

Abstract

OBJECTIVEHemifacial spasm (HFS), largely caused by neurovascular compression (NVC) of the facial nerve, is a rare condition characterized by paroxysmal, unilateral, involuntary contraction of facial muscles. It has long been suggested that these symptoms are due to compression at the transition zone of the facial nerve. The aim of this study was to examine symptom-free survival and long-term quality of life (QOL) in HFS patients who underwent microvascular decompression (MVD). A secondary aim was to examine the benefit of utilizing fused MRI and MRA post hoc 3D reconstructions to better characterize compression location at the facial nerve root exit zone (fREZ).METHODSThe authors retrospectively analyzed patients with HFS who underwent MVD at a single institution, combined with a modified HFS-7 telephone questionnaire. Kaplan-Meier analysis was used to determine event-free survival, and the Wilcoxon signed-rank test was used to compare pre- and postoperative HFS-7 scores.RESULTSThirty-five patients underwent MVD for HFS between 2002 and 2018 with subsequent 3D reconstructions of preoperative images. The telephone questionnaire response rate was 71% (25/35). If patients could not be reached by telephone, then the last clinic follow-up date was recorded and any recurrence noted. Twenty-four patients (69%) were symptom free at longest follow-up. The mean length of follow-up was 2.4 years (1 month to 8 years). The mean symptom-free survival time was 44.9 ± 5.8 months, and the average symptom-control survival was 69.1 ± 4.9 months. Four patients (11%) experienced full recurrence. Median HFS-7 scores were reduced by 18 points after surgery (Z = −4.013, p < 0.0001). Three-dimensional reconstructed images demonstrated that NVC most commonly occurred at the attached segment (74%, 26/35) of the facial nerve within the fREZ and least commonly occurred at the traditionally implicated transition zone (6%, 2/35).CONCLUSIONSMVD is a safe and effective treatment that significantly improves QOL measures for patients with HFS. The vast majority of patients (31/35, 89%) were symptom free or reported only mild symptoms at longest follow-up. Symptom recurrence, if it occurred, was within the first 2 years of surgery, which has important implications for patient expectations and informed consent. Three-dimensional image reconstruction analysis determined that culprit compression most commonly occurs proximally along the brainstem at the attached segment. The success of this procedure is dependent on recognizing this pattern and decompressing appropriately. Three-dimensional reconstructions were found to provide much clearer characterization of this area than traditional preoperative imaging. Therefore, the authors suggest that use of these reconstructions in the preoperative setting has the potential to help identify appropriate surgical candidates, guide operative planning, and thus improve outcome in patients with HFS.

Hemifacial Spasm: Comparison of Results between Patients Older and Younger than 70 Years Operated on with Microvascular Decompression

“…Generally, it is well known that HFS is due to vascular compression of the facial nerve at the root entry zone (REZ) in the brainstem by AICA or other vessels. 7 For this reason, MVD of the facial nerve REZ in the posterior cranial fossa is considered the etiological treatment for HFS, with the highest efficacy and durability of all available treatments, representing the treatment of first choice for medically refractory HFS. Owing to postulated peril of MVD-related complications, mortality with general anesthesia, and the shorter remaining life expectancy, some less invasive procedures (BtNtA, acupuncture) are often proposed for elderly patients, with acceptable but not always durable results.…”

Fully endoscopic microvascular decompression for hemifacial spasm

“…When the patient is excited or nervous, the condition may become more severe, and patient may even have difficulty in opening their eyes, develop crooked mouth corners or suffer from twitch-like noises in the ears ( 2-4 ). The facial muscle spasm usually begins with the orbicularis oculi muscle and eventually involves the ipsilateral facial muscles innervated by the facial nerve; however, most patients only have one side facial muscle spasm, and very few patients have bilateral facial muscle spasm ( 5 , 6 ). The annual incidence rate of HFS is ~11 cases/1,000,000 individuals, with most cases beginning in middle age ( 7 ).…”

Endoscopic microvascular decompression for hemifacial spasm

“…[ 5 ] Involuntary facial movements have various psychosocial consequences for patients can be very debilitating and lead to a general decrease in the quality of life. [ 6 7 ]…”

“…[ 4 ] Secondary HFS has been reported through a variety of mechanisms, including cerebellopontine angle masses, arteriovenous malformations, enterogenous cysts, and aneurysms. [ 2 7 8 9 ]…”

“…The anterior inferior cerebellar artery (AICA), posterior inferior cerebellar artery, and vertebral artery (VA) are the most frequently implicated vessels in HFS. [ 3 7 10 11 ]…”