Challenging Microvascular Decompression Surgery for Hemifacial Spasm

Efficacy and safety of botulinum neurotoxin in the treatment of hemifacial spasms: a systematic review and meta-analysis

BACKGROUND

Hemifacial spasm (HFS) is a neuromuscular disorder characterized by unilateral facial muscle spasms, negatively impacts quality of life due to social embarrassment. Botulinum Neurotoxin (BoNT) injections have emerged as a viable therapeutic approach. This systematic review evaluated the efficacy and safety of BoNT injections for HFS management, along with effects on patients' quality of life and mental health.

MATERIALS AND METHODS

A systematic search for studies on BoNT treatment for HFS published between January 1, 2000, and May 1, 2024, was performed across major databases. Study quality was evaluated using Cochrane and Joanna Briggs Institute (JBI) tools, with data management handled by EndNote X9 and statistical analyses conducted via Review Manager (RevMan 5.4) and STATA 14.0.

RESULTS

Thirty-five studies met the inclusion criteria: 2 RCTs comprising 83 HFS patients compared the efficacy of perioral injections of botulinum toxin and placebo, while 33 single-arm studies reported outcomes for 2786 patients post-BoNT injection. The selection of 17 single-arm studies focused on the effectiveness rate as the key outcome metric. Pooled estimate signified a remarkably high effectiveness (ES: 0.882, 95% CI: 0.830, 0.926, P < 0.001). Analysis of depression scale (SMD: -0.85, 95% CI: -1.34, -0.35, P < 0.001), anxiety scale (SMD: -1.50, 95% CI: -2.19, -0.80, P < 0.001) and total scale of quality of life (SMD: -0.64, 95% CI: -0.87, -0.41, P = 0.766) showed that BoNT therapy worked well especially in improving mental state and quality of life. Ptosis was considered as the most common adverse reaction during BoNT injections (OR: 0.30, 95% CI: 0.11, 0.81, P = 0.843).

CONCLUSION

BoNT injection showed validity and clinical safety in the treatment of HFS, particular for depression relief. Injections around the mouth were only effective for HFS cases with severe symptoms. A standardized strategy for BoNT injections in managing HFS, detailing parameters such as injection sites, doses, and frequencies, remained elusive. Additional RCTs are necessary to further elucidate the interplay between efficacy and these components.

Hemifacial spasms triggered by compression of tortuous anterior inferior cerebellar artery loop on the facial nerve in the internal auditory canal: A case report

RATIONALE

Hemifacial spasm (HFS) is triggered by neurovascular compression mostly at the root entry/exit zone of the facial nerve. HFS with the responsible blood vessel located in the internal auditory canal (IAC) is a very rare occurrence. In our case, the HFS was triggered by compression of the anterior inferior cerebellar artery (AICA) loop on the facial nerve in the IAC.

PATIENT CONCERNS

A 27-year-old female presented with a 5-year history of right-sided facial twitching with no obvious course. The frequency and severity of the attacks increases when the patient was anxious or agitated which severely affected her quality of life.

DIAGNOSIS

Preoperative 3D-TOF magnetic resonance imaging (MRI) evaluation of cranial nerves showed that the right AICA loop had a tortuous course within the IAC and compressed the facial nerve.

INTERVENTION

Microvascular decompression (MVD) surgery was carried out to separate the tortuous AICA loop and facial nerve in the IAC using a Teflon pad.

OUTCOMES

The abnormal muscle response disappeared intraoperatively and 2-years follow-up revealed no recurrence of her symptomatology. She is current well and go about her daily activities with no neurological deficits.

LESSON

The attachment of the facial nerve to the tortuous AICA loop coupled with the pulsatile impulse of tortuous AICA loop may have resulted in the entrapment and compression of the CN VII in the IAC.

Benchtop and in Vitro Experiments of Novel Transform Stents for Trigeminal Neuralgia Treatment

BACKGROUND

Trigeminal neuralgia (TN) is a debilitating condition characterized by sudden, excruciating facial pain due to neurovascular compression of the trigeminal nerve. Stent deployment can change the course of the superior cerebellar artery upwards, possibly releasing the root entry zone of the trigeminal nerve. We developed a novel stent, the Transform stent, for TN treatment, and evaluated its mechanical properties using benchtop and in vitro hemocompatibility tests.

METHODS

We compared the performance of Transform and Enterprise stents in treating TN because they share similar self-expanding closed-cell features in the manufacturing process, are derived from nitinol tubes, and are fabricated through a laser-cutting process, but also because only the safety of Enterprise stents deployed in intracranial arteries has been reported clinically. All benchtop measurements, including radial force, trackability, bending stiffness, and conformability, were performed thrice for each stent model, and their average values are presented.

RESULTS

Transform stents showed higher radial forces in vessels of diameters ranging from 1.0 mm than Enterprise stents. The trackability of the Transform stent was better than that of the Enterprise stent in a neurovascular model. Bending stiffness was stronger in the Transform stent whereas conformability was superior in the Enterprise stent. No significant thrombogenic issues were observed in the in vitro hemocompatibility tests.

CONCLUSIONS

This study demonstrated the Transform stent as a potential option and paved the way for innovative endovascular approaches for the future TN treatment. Namely, the study confirmed that the characteristics of Transform stents at benchtop and in vitro evaluations may be used as a first step for studies such as in vivo pre- and clinical studies.

Evaluating magnetic resonance imaging characteristics and risk factors for hemifacial spasm

PURPOSE

The specific neurovascular compression (NVC) event responsible for the symptomatic manifestation of hemifacial spasm (HFS) remains difficult to assess accurately using magnetic resonance imaging (MRI). We aim to evaluate the MRI characteristics of HFS.

METHOD

We retrospectively included patients with HFS and divided them into a test group (n = 186) and a validation group (n = 28). The presence, severity, and offending vessel type of NVC in each portion, and the orientation of the offending vessel around the facial nerve, were recorded. Conditional logistic regression analyses were performed to evaluate correlations using test group. The validation group was used to verify whether our findings improved diagnostic performance.

RESULTS

Deformity in the proximal cisternal segment was significantly correlated with HFS occurrence (odds ratio [OR]: 256.58, p = .002), whereas contact was not (p = .233). Both contact and deformity in the root detachment point (OR: 19.98 and 37.22, p < .001 and p = .013, respectively) or attached segment (OR: 4.99 and 252.52, p = .001 and p < .001, respectively) were significantly correlated with HFS occurrence. Our findings improved specificity, positive predictive value, and accuracy of diagnosis than conventional diagnostic methods. The vertebral artery predominantly compress the facial nerve in the inferior-anterior position, the anterior inferior cerebellar artery predominantly in the inferior position, the posterior inferior cerebellar artery predominantly in the inferior position, vein predominantly in the posterior-superior position.

CONCLUSIONS

This study further demonstrates that within the susceptible portion of facial nerve, different portions of the nerve respond differently to NVC. Each offending vessel has its own preferred conflict orientation. Our study offers reference for neurosurgeons in diagnosis and treatment.

A novel non-segmented inverted water outline rendering method can improve the tracking of responsible blood vessels for hemifacial spasm

This study aimed to explore a novel, non-segmented based on inverted water outline, and rapid 3D rendering method for identifying the responsible blood vessels for hemifacial spasm. First, the software was developed using the free and open-source 3D Slicer to process magnetic resonance images. Outlines of the water region were extracted and rendered in a three-dimensional space. The traditional image re-slicing technique (IMRT) was used for the control group, while non-segmented inverted water outline rendering (NSIWR) was used to observe the relevant blood vessels in the root entry/exit zone (REZ) of patients with hemifacial spasm. The intraoperative exploration results were considered the gold standard for comparing the differences in identifying relevant blood vessels between the two methods. Twenty-five patients were included, and the reconstruction effect evaluation suggested that NSIWR could effectively reconstruct the responsible blood vessels of the cochlea, facial nerve, and REZ. Compared with IMRT, NSIWR effectively improved the diagnosis of the responsible blood vessels in the REZ, clarified their sources and directions, and was consistent with intraoperative results. This study introduced a novel rapid rendering method based on NSIWR, which was successfully applied for hemifacial spasm. The method enhances accuracy in identifying responsible blood vessels in the REZ without needing multi-modal techniques. It has the potential to improve surgical effectiveness and reduce exploration time in treating hemifacial spasm.

Outcomes after Microvascular Decompression for Hemifacial Spasm without Definite Radiological Neurovascular Compression at the Root Exit Zone

The purpose of this study was to investigate the outcome of microvascular decompression (MVD) in patients with hemifacial spasm (HFS) who have no definite radiological neurovascular compression (NVC). Sixteen HFS patients without radiological NVC on preoperative MRI underwent MVD surgery. The symptoms were left-sided in fourteen (87.5%) and right-sided in two patients (12.5%). Intraoperatively, the most common vessel compressing the facial nerve was the AICA (8, 44.4%), followed by arterioles (5, 27.8%), veins (4, 22.2%), and the PICA (1, 5.6%). The most common compression site was the cisternal portion (13, 76.5%) of the facial nerve, followed by the REZ (4, 23.5%). One patient (6.3%) was found to have multiple NVC sites. Arachnoid type (7, 50%) was the most common compressive pattern, followed by perforator type (4, 28.6%), sandwich type (2, 14.3%), and loop type (1, 7.1%). A pure venous compression was seen in two patients, while a combined venous-arterial "sandwich" compression was detected in two patients. Symptom improvement was observed in all of the patients. Only one patient experienced recurrence after improvement. Based on our experience, MVD surgery can be effective for primary HFS patients with no definite radiological NVC. MVD can be considered if the patient shows typical HFS features, although NVC is not evident on MRI.

Penetrating Offenders in Hemifacial Spasm: Surgical Tactics and Prognosis

(1) Background: In cases of hemifacial spasm (HFS), there are various patterns related to the vascular compression of the facial nerve, including a very rare form that is seen when the offending vessel penetrates the facial nerve. However, there have been few reports in the literature regarding the associated surgical techniques and postoperative prognosis. (2) Methods: A retrospective review was conducted of 4755 patients who underwent microvascular decompression (MVD) surgery from April 1997 to June 2023. In total, 8 out of the 4755 patients (0.2%) exhibited a penetrating offending vessel; the medical and surgical records of these 8 patients were then analyzed. Surgery was then attempted to maximally decompress the penetrating offender. (3) Results: Seven out of the eight patients (87.5%) were spasm-free immediately after surgery, and one had only 10% residual spasm compared to their preoperative condition. That patient was also spasm-free one year later. Postoperative facial palsy occurred in one patient (12.5%) who was assessed as grade II in the House-Brackmann grading system. In another patient, the resection of a small facial nerve bundle did not result in facial palsy. There were no cases of hearing loss or other complications. (4) Conclusions: Decompressing the penetrating offender did not increase the incidence of facial palsy, and the prognosis for hemifacial spasms was good. Therefore, when a penetrating pattern was encountered during MVD surgery, decompression between the penetrating offender and the facial nerve may offer good results.

Operative Findings of over 5000 Microvascular Decompression Surgeries for Hemifacial Spasm: Our Perspective and Current Updates

Hemifacial spasm (HFS) is a hyperactive cranial neuropathy, and it has been well established that the cause of primary HFS is compression on the root exit zone (REZ) of the facial-vestibulocochlear nerve complex (CN VII-VIII) by a vessel or vessels. MVD is the only curative treatment option for HFS with a high success rate and low incidence of recurrence and complications. We categorize six classical compressive patterns on the REZ as well as five challenging types. Knowledge of these patterns may help in achieving a better surgical outcome.

Fully Endoscopic Microvascular Decompression for Hemifacial Spasm Using Improved Retrosigmoid Infrafloccular Approach: Clinical Analysis of 81 Cases

BACKGROUND

Microvascular decompression (MVD) is widely accepted as the preferred treatment for hemifacial spasm (HFS). Endoscopy has been implemented to provide a comprehensive view of neurovascular conflicts and minimize the damage caused by brain retraction while exploring the facial nerve root exit zone of the brain stem.

OBJECTIVE

To preliminarily evaluate the surgical safety and efficacy of fully endoscopic MVD for HFS using an improved retrosigmoid infrafloccular approach.

METHODS

The clinical data of 81 patients with HFS who underwent fully endoscopic MVD using an improved endoscopic retrosigmoid infrafloccular approach from June 2019 to December 2020 were retrospectively analyzed. The reliability and advantages of this surgical technique in the treatment of HFS were evaluated according to the intraoperative situation, outcomes of postoperative symptoms, and main complications.

RESULTS

During the follow-up period, 77 cases (95.1%) were completely cured, with immediate facial twitch disappearance in 56 cases and a delayed cure in 21 cases; in 4 cases (4.9%), there was no obvious improvement. There were no cases of recurrence. There were 4 cases (4.9%) of transient facial paralysis after MVD, all of which were completely cured in 3 months. Three cases (3.7%) had hearing loss postoperatively, of whom 2 showed good improvement. At the end of the follow-up period, 1 case (1.2%) still had tinnitus. There were no cases of postoperative intracranial hemorrhage, cerebellar swelling, or death.

CONCLUSION

Fully endoscopic MVD using an improved retrosigmoid infrafloccular approach not only has the advantages of panoramic surgical visualization but also takes into account the requirements of minimally invasive surgery.