Flat-shaped posterior cranial fossa was associated with poor outcomes of microvascular decompression for primary hemifacial spasm

The progress in epidemiological, diagnosis and treatment of primary hemifacial spasm

Hemifacial Spasm is a neurological disorder characterized by persistent and rhythmic spasms of the facial muscles, significantly affecting the patient's quality of life. This condition can be classified into primary and secondary types; this article focuses on the characteristics of primary hemifacial spasm. Epidemiological studies indicate that the condition is more common in women, older adults, and individuals with posterior fossa stenosis or uneven blood flow dynamics, and is associated with gene expression related to demyelinating lesions. In terms of diagnosis, magnetic resonance imaging can show the location of arterial or venous compression on the facial nerve on a macroscopic level and reveal white matter lesions on a microscopic level. Additionally, optimized electrophysiological techniques can determine the type of neural excitation disorder from both central and peripheral perspectives, thereby improving detection rates. There are numerous treatment options available. Although early oral medications may have limited effectiveness, botulinum toxin injections can provide temporary relief. Future considerations include balancing injection costs with long-term efficacy. Microvascular decompression remains the preferred treatment approach and can be further optimized with endoscopic techniques. For refractory cases, alternative therapies such as facial nerve massage, radiofrequency techniques, rhizotomy, or acupuncture may be considered.

Decompression Surgery in Elderly Patients with Hemifacial Spasm Refractory to Botulinum Toxin

BACKGROUND

Botulinum toxin is an effective treatment for hemifacial spasm in elderly patients. However, some patients do not tolerate the side effects and frequency of botulinum toxin treatments.

OBJECTIVES

The purpose of this study was to evaluate the characteristics and outcomes of a cohort of elderly patients referred by neurologists for surgical decompression of the facial nerve following botulinum toxin treatment.

METHODS

In a prospective cohort study, logistic regression was used to detect potential predictors of spasm-freedom after surgical decompression of the facial nerve in elderly patients that received ≤8 and >8 botulinum toxin treatments for hemifacial spasm before surgery. Age, sex, side, preoperative symptom duration, and preoperative botulinum toxin treatment were assessed as potential predictors of spasm-freedom at last follow-up.

RESULTS

Of 76 elderly patients with hemifacial spasm treated with botulinum toxin and microvascular decompression, with at least 2-years of follow-up (median, 44.5 months), 84.2% were spasm-free at last follow-up. Age (P = 0.38), sex (P = 0.59), side (P = 0.15), preoperative symptom duration (P = 0.7), and number of preoperative botulinum toxin treatments (P = 0.3) were not predictors of long-term spasm-freedom. Permanent ipsilateral hearing loss was the most frequent complication (3.9%).

CONCLUSION

This study provides evidence that elderly patients can undergo botulinum toxin treatment for hemifacial spasm without compromising their likelihood of achieving spasm-freedom with future surgical decompression. Therefore, surgical decompression of the facial nerve is an effective therapy for elderly patients with hemifacial spasm refractory to botulinum toxin.

Posterior Fossa Volume and Dimensions: Relation to Pathophysiology and Surgical Outcomes in Classic Trigeminal Neuralgia

OBJECTIVE

A small posterior fossa (PF) has been hypothesized to explain the increased incidence of trigeminal neuralgia (TN) in females and could make microvascular decompression (MVD) more challenging. The aim of this study was to investigate the association between the PF volume and dimensions in relation to biological sex, type of neurovascular conflict (NVC), and outcome after MVD in classic TN.

METHODS

In this observational study, 84 patients with TN operated on with MVD with a preoperative head computed tomography(CT) scan were included. Eighty-two adults without TN who had undergone head CT for other reasons were included as controls. PF volume and dimensions (x-axis, y-axis, and z-axis) were evaluated on the CT scans. For the patients with TN, Barrow Neurological Institute (BNI) grade was evaluated 6 months after MVD.

RESULTS

There was no difference in PF volume or dimensions between the patients with TN and controls. Women showed a smaller volume and narrower (x-axis) PF than men, but these differences did not manifest when comparing patients with TN and controls within each sex. Patients with an NVC involving the superior cerebellar artery had a narrower (x-axis) and shorter (y-axis) PF than did patients with an NVC resulting from other arteries. PF volume or dimensions were not associated with BNI grade after MVD.

CONCLUSIONS

PF anatomy was related to the NVC type but did not differ between patients with TN and controls and was not related to the surgical outcome after MVD.

Factors Related to Hemifacial Spasm Recurrence in Patients Undergoing Microvascular Decompression—A Systematic Review and Meta-Analysis

There is a lack of knowledge about the factors associated with the recurrence of hemifacial spam (HFS) following an initially successful microvascular decompression (MVD) surgery. The aim of the present study was to systematically review the pertinent literature and carry out a meta-analysis of factors linked to HFS recurrence in patients undergoing initially successful MVD treatment. An online literature search was launched on the PubMed/Medline and Scopus databases. The following data were collected: sex, age at surgery, affected side, reported improvement after surgery, presence of post-operatory facial weakness, symptom duration, offender vessels, and data obtained from intraoperative neurophysiological monitoring. Upon full-text review, eight articles were included, studying 1105 patients, of which 64 (5.7%) reported recurrence after MVD surgery for hemifacial spasm. There was a statistically significant increased incidence of HFS recurrence in patients with the persistence of lateral spread response (LSR after surgery (OR 9.44 (95% CI 1.69–52.58) p 0.01), while those patients experiencing a shorter disease duration before going to surgery were significantly less prone to experiencing disease recurrence (OR 0.11 (95% CI 0.03–0.46) p 0.002). The remaining examined factors did not result as significantly associated with the risk of recurrence. The funnel plots were largely symmetrical for each variable studied. Taken together, the results of our meta-analysis seem to suggest that short-term symptom duration is a protective factor against HFS recurrence after MVD surgery, while LSR persistence is a negative prognostic factor. Well-designed randomized controlled clinical trials with a long follow-up are expected to further explore therapeutic alternatives for HFS recurrence.

Microscopic versus endoscopic microvascular decompression for the treatment of hemifacial spasm in China: A meta-analysis and systematic review

OBJECTIVE

To date, microvascular decompression has become the standard surgical treatment for hemifacial spasm. Microscopic microvascular decompression (MI-MVD) and endoscopic microvascular decompression (E-MVD) are both popular with surgeons. The present study aims to investigate whether MI-MVD and E-MVD show better results as surgical treatments for hemifacial spasm in the Chinese population.

METHODS

Electronic retrieval of articles on PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure and Wanfang Database was performed to identify comparative studies on Chinese patients who underwent MI-MVD and E-MVD from January 2000 to December 2020. After data extraction and quality assessment of the included studies, a meta-analysis was performed using the Review Manager 5.4 software. The pooled incidence of patient effective rate, detection rate of offensive blood vessels, total complication rate, and recurrence rate were calculated.

RESULTS

A total of 12 studies with 1122 patients (MI-MVD: 562, E-MVD: 560) were identified. The patient effective rate (MI-MVD: 89% vs E-MVD:97%, OR = 0.22, P < 0.00001) and detection rate of offensive blood vessels (MI-MVD:91% vs E-MVD:98%, OR = 0.17, P = 0.0002) showed patients with E-MVD were significantly higher than patients who underwent MI-MVD. However, the total complication rate (MI-MVD: 27% vs E-MVD:12%, OR = 2.92, P = 0.0002) and recurrence rates (MI-MVD:5.7% vs E-MVD:0.3%, OR = 8.8, P = 0.0005) showed patients with E-MVD were significantly lower than patients who underwent MI-MVD. In addition, the incidence of facial paralysis or weakness and hearing loss in E-MVD group was lower than that of in MI-MVD group, whereas no statistical difference was found between the two groups in terms of the incidence of cerebrospinal fluid leakage and intracranial infection.

CONCLUSIONS

While the operation of MI-MVD is relatively simple and the learning curve is short, E-MVD is better than MI-MVD in terms of treatment effect, overall complications, and recurrence rate. Therefore, E-MVD can be used as an alternative to MI-MVD in the treatment of hemifacial spasm in the Chinese population.

Comparative Analysis of Trigeminal Neuralgia Caused by Sole Arterial and Venous Compression: Clinical Features and Surgical Outcomes From 222 Cases

Background: Compared with trigeminal neuralgia (TN) caused by arterial neurovascular conflict (NVC), the clinical characteristics and managements for TN with venous NVC are not well-established. This study aims to comparatively summarize the clinical features and surgical outcomes of microvascular decompression (MVD) for patients with TN caused by sole arterial and venous compression, with a particular focus on the morphological features of posterior cranial fossa (PCF).

Methods: A total of 222 patients with TN caused by sole arterial NVC (188/84.7%) and venous NVC (34/15.3%) underwent MVD in our department from January 2014 to December 2018. The patient data were analyzed retrospectively. Particularly, we focused on the potential impact of PCF on surgical outcomes.

Results: Compared with arterial NVC, V3 branch of the trigeminal nerve was more frequently involved in venous NVC (p = 0.009). The most common compression site was root entry zone for arterial NVC (68.6%) and midcisternal segment for venous NVC (76.5%) (p < 0.001). No serious post-operative complication was observed in the two groups. Both short- and long-term outcomes were relatively worse in venous NVC cases compared with arterial NVC cases (p = 0.001 and p = 0.030, respectively); and a dominantly higher rate of delayed cure was demonstrated in venous NVC cases (p < 0.001). TN patients with venous NVC revealed a more flat-shaped PCF than those with arterial NVC. Moreover, flat-shaped PCF morphometry was negatively correlated with surgical outcomes of TN patients with arterial NVC, but not with those of venous NVC cases.

Conclusions: MVD is an effective and safe treatment for patients with TN caused by either arterial or venous NVC. Patients with a more flat-shaped PCF might be vulnerable to venous compression. Our study demonstrated that PCF morphometry only affected the surgical outcomes of patients with TN caused by arterial NVC, but not the outcomes of those with venous NVC.