Supine No-Retractor Method in Microvascular Decompression for Hemifacial Spasm: Results of 100 Consecutive Operations

Hemifacial Spasm Associated With the Specific Offending Vein

BACKGROUND AND OBJECTIVES

Hemifacial spasm (HFS) caused by venous compression is a rare occurrence. Currently, there is no relevant research on the venous characteristics and potential pathogenic mechanisms causing venous HFS. Exploring the venous characteristics in venous-type HFS may reduce the likelihood of repeated surgery.

METHODS

The authors presented 4 cases of HFS caused by veins of middle cerebellar peduncle (V. of Mid.Cer.Ped) successfully treated with microvascular decompression.

RESULTS

Based on intraoperative observations and abnormal muscle response (AMR) monitoring, it was determined that V. of Mid.Cer.Ped were offending vessels in these patients. Moreover, veins crossed between the facial and vestibulocochlear nerves, and then surrounded the ventral aspect of the facial nerve root. Microvascular decompression for the offending vessel was successfully performed, and AMR disappeared for each patient. These patients were discharged without any complications and involuntary contractions or twitching of facial muscles.

CONCLUSION

The study demonstrated that veins can indeed induce HFS. The characteristic of the V. of Mid.Cer.Ped that leads to HFS is that these veins traverse between the facial nerve and the vestibulocochlear nerve, and then surround the ventral aspect of the facial nerve root. The dynamic influence of cerebrospinal fluid leads to pulsatile impingement of the facial nerve on the vein, resulting in facial nerve bending and deformation at the location of the vein. Significantly, in the context of surgery, if it is noticed that the V. of Mid.Cer.Ped surrounds the ventral aspect of the facial nerve root and the facial nerve is compressed and deformed, when AMR disappears after decompression of the artery, it may be necessary to perform vein decompression.

The outcomes of microvascular decompression for primary trigeminal neuralgia: insights from a single-center experience and technical advancements

Background

Microvascular decompression (MVD) remains the primary surgical treatment for trigeminal neuralgia due to its positive postoperative results. This study aims to evaluate the outcomes of patients with primary trigeminal neuralgia who underwent MVD. Additionally, the paper offers a detailed explanation of the surgical methodology of MVD employed at the neurosurgical hospital in Kazakhstan.

Methods

The study involved 165 medical records of patients with trigeminal neuralgia who underwent MVD between 2018 and 2020. Out of these 165 patients, 90 (54.55%) were included in the final analysis and were further evaluated using the Barrow Neurological Institute pain intensity score. Various variables were analyzed, including age, sex, affected side, dermatomes, offending vessel, and surgical intervention type. Moreover, the surgical technique employed at the hospital was described.

Results

The average follow-up period after the MVD procedure was 32.78 ± 9.91 months. The results indicated that out of the 90 patients, 80 (88.89%) achieved a good outcome as evidenced by BNI scores I and II. It was observed that patients with affected maxillary dermatomas and those with affected ophthalmic + maxillary dermatomas were more likely to experience fair + poor postsurgery BNI scores. On the other hand, patients with neurovascular conflicts involving the maxillary + mandibular dermatomas demonstrated good BNI scores (p = 0.01).

Conclusions

The outcomes of MVD in patients with primary trigeminal neuralgia showed good BNI scores within this study population. The outcome depended on the affected dermatome of the trigeminal nerve with the vessel. Additionally, patient positioning, intraoperative management including small skin incisions, minimal craniotomy, and precise closure of the dura, as well as intraoperative neurolysis, may contribute to achieving good clinical and satisfactory post-surgery aesthetic outcomes.

Glossopharyngeal and vagoglossopharyngeal neuralgia: Long-term surgical outcomes in a single institution

BACKGROUND

Glossopharyngeal neuralgia (GPN) and vagoglossopharyngeal neuralgia (VGPN) are infrequent syndromes that can have great negative impact on a patient's quality of life. The objective of this study is to describe the characteristics and long-term results of patients with GPN-VGPN who are treated surgically with microvascular decompression (MVD) in one institution.

METHODS

This is a retrospective series of 20 patients with the diagnosis of GPN-VGPN who underwent MVD. Demographic characteristics, surgical results, complications, and long-term follow-up were analyzed.

RESULTS

The mean age of symptom onset was 51.25 years and the majority of patients were women (60%). The posterior inferior cerebellar artery was the main offending vessel (75%). The immediate MVD success rate was 100%, but during follow-up, two patients (10%) were diagnosed with VGPN and both cases presented pain recurrence. The mean follow-up was 120.4 (25-333) months. VGPN (P = 0.005) and a ≥5 day hospital stay (P = 0.032) were associated with unsuccessful outcomes. Two complications were documented, which resolved without sequelae. There was no surgical mortality.

CONCLUSION

MVD is an effective and safe treatment for long-term pain relief of GPN-VGPN. VGPN and a prolonged hospital stay were associated with poor outcomes. More studies are required to confirm these findings.

Meningitis after elective intracranial surgery: a systematic review and meta-analysis of prevalence

Meningitis is a potential complication of elective intracranial surgery (EIS). The prevalence of meningitis after EIS varies greatly in the literature. The objective of this study was to estimate the overall pooled prevalence of meningitis following EIS. Four databases (PubMed, Scopus, Web of Science, and Embase) were searched to identify relevant studies. Meta-analyses of proportions were used to combine data. Cochran's Q and I² statistics were used to assess and quantify heterogeneity. Additionally, several subgroup analyses were conducted to investigate the source of heterogeneity and examine differences in the prevalence based on variables such as geographical regions, income level, and meningitis type. The meta-analysis included 83 studies (30 959 patients) from 26 countries. The overall pooled prevalence of meningitis after EIS was 1.6% (95% CI 1.1-2.1), with high heterogeneity present (I² = 88%). The pooled prevalence in low- to middle-income countries and high-income countries was 2.7% (95% CI 1.6-4.1) and 1.2% (95% CI 0.8-1.7), respectively. Studies that reported only aseptic meningitis had a pooled prevalence of 3.2% (95% CI 1.3-5.8). The pooled prevalence was 2.8% (95% CI 1.5-4.5) in studies that reported only bacterial meningitis. Similar prevalence rates of meningitis were observed in the subgroups of tumor resection, microvascular decompression, and aneurysm clipping. Meningitis is a rare but not exceptional complication following EIS, with an estimated prevalence of 1.6%.

Proper Head Rotation when Performing Microvascular Decompression for Hemifacial Spasm: An Orthometric Consideration Based on Preoperative MRI

BACKGROUND

 The classic surgical position for microvascular decompression (MVD) is lateral decubitus with the head rotated 10 degrees away from the affected side. In this study, we measured the angles of the posterior fossa, specifically focusing on the surgical corridors used in MVD surgery for hemifacial spasm (HFS), to identify the proper surgical position.

METHOD

 The following parameters were assessed on preoperative magnetic resonance images (MRI): petrous angle (PA), sigmoid angle (SA), sigmoid diameter (SD), and root exit zone-sigmoid sinus edge angle (REZ-SEA).

RESULTS

 The mean PA was 59.7 ± 5.6 degrees, SA was 16.8 ± 8.6 degrees, SD was 13.4 ± 3.5 mm, and the mean REZ-SEA was 59.6 ± 5.8 degrees. The difference between the maximum SA to avoid cerebellar hemisphere injury and the minimum REZ-SEA required to verify the facial nerve REZ is assumed to be the usable range of angles for the operative microscope; the average midpoint of this range was 38.2 ± 6.4 degrees.

CONCLUSION

 Turning the patient's head 10 degrees away from the affected side was generally appropriate for performing MVD surgery because it provided a mean microscope angle of 48 degrees. However, some patients had corner values for the sigmoid angle, REZ-SEA, and sigmoid sinus diameter. Rotating a patient's head based on precise calculations from preoperative MRI helps to achieve successful surgery.

Factors Related to the Delayed Cure of Hemifacial Spasm after Microvascular Decompression: An Analysis of 175 Consecutive Patients

Detailed studies assessing the factors related to delayed cure of hemifacial spasm (HFS) after microvascular decompression (MVD) are sparse. We aimed to evaluate the effect of 11 clinical factors on the time until the patient became spasm free after MVD. We enrolled 175 consecutive patients with HFS who underwent MVD between 2012 and 2018. The end point was defined as the time point at which the patient became spasm free based on the outpatient interview. Patients were divided into six groups depending on when they became spasm free after the operation, as follows: <7 days ( n  = 62), 7 days to 1 month ( n  = 28), 1 to 3 months ( n  = 38), 3 to 6 months ( n  = 25), 6 to 12 months ( n  = 17), and >12 months ( n  = 5). The median time to become spasm free after MVD was 30.0 days. Association of 11 factors (age, sex, laterality, number of offending arteries, vertebral artery compression, number of compression sites, compression at root detachment zone, preoperative Botox treatment, indentation of the brain stem on preoperative magnetic resonance image, transposition, and interposition) with spasm-free rate was assessed using the Cox's proportional hazards model. Spasm-free rate curve after MVD for the significant factor was obtained using the Kaplan-Meier method. In univariate and multivariate analyses, nontransposition was significantly related to delayed HFS cure after MVD (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.42, 0.87; p  = 0.0068 and HR, 0.60; CI, 0.43, 0.85; p  = 0.042, respectively). The spasm-free rate was higher in the transposition than in the nontransposition group ( p  = 0.0013). As shortening the time until spasm free after MVD improves patients' quality of life, transposition should be recommended. Prediction of spasm-free time could relieve the anxiety of postoperative patients.

Hemifacial Spasm Caused by a Vein: A Case Report

Hemifacial spasm (HFS) caused by a venous offender is rare, and its clinical course and optimal surgical strategy are unclear. A case of 57-year-old male who had an HFS caused by a venous offender is described in this report. Frontalis, orbicularis oculi, orbicularis oris, and mentalis muscles were involved while his platysma muscle showed no spasm. He was treated successfully with microvascular decompression using Teflon felt and 12 months outcome was excellent without any complications. Lateral spread response was not observed in the facial electromyography during the whole operation. Adequate visualization of the facial nerve root exit zone and meticulous exploration for offenders are necessary to avoid surgical failure and reoperation.

Veins of the Cerebellopontine Angle and Specific Complications of Sacrifice, with Special Emphasis on Microvascular Decompression Surgery. A Review

Good knowledge of the anatomy of veins is of crucial importance for the functional surgery of cranial nerve (CN) disorders, especially microvascular decompression for trigeminal neuralgia (TN), hemifacial spasm (HFS), and vagoglossopharyngeal neuralgia (VGPN). Although controversial, veins may be involved in neurovascular conflicts and may constitute dangerous obstacles to access to the CNs. With the aim of estimating the implications of veins in those diseases and evaluating the linked surgical difficulties, we carried out a review of the literature from 2000 to the end of February 2018. For this review, articles found on PubMed that gave enough precision about veins were retained (39 articles on TN, 38 on HFS, 8 on VGPN, and 26 on complications related to venous sacrifices). Before this review, we described a simplified anatomic classification of veins, amenable to easing the surgical approach to CNs. Access to the trigeminal nerve, via the infratentorial-supracerebellar route, is almost always affected by the superficial superior petrosal venous system, whereas access to the facial and cochleovestibular complex as well as to the lower CNs, through the infrafloccular trajectory, is almost always exempt of important venous obstacles. Respective incidences of venous compression at the origin of hyperactive CN syndromes are given. The percentages of a venous conflict alone were calculated at 10.8% for TN, 0.1% for HFS, and 2.9% for VGPN. We review the complications considered in relation with venous sacrifices. Precautions to minimize these complications are given.

Intraoperative monitoring of Z-L response (ZLR) and abnormal muscle response (AMR) during microvascular decompression for hemifacial spasm. Interpreting the role of ZLR

BACKGROUND

Z-L response (ZLR) has been suggested to a new electromyographic (EMG) potential recorded from the facial muscle of patient with hemifacial spasm (HFS) during microvascular decompression (MVD). Although ZLR has been suggested to be useful, experience of ZLR monitoring is limited and its significance during MVD is still unclear.

METHODS

To investigate the significance of ZLR, both ZLR and abnormal muscle response (AMR) were simultaneously recorded before and after decompression of root exit zone (REZ) in 20 consecutive patients with HFS.

RESULTS

All 19 AMRs elicited before REZ decompression disappeared immediately after decompression of REZ. ZLRs were also observed before decompression of REZ in 19 (95%) of 20 patients. Despite negative conversion of AMR after decompression in 19 patients, ZLR disappeared in only 13 (68.4%) of 19 patients. Among six sustained ZLRs, three showed reduction in the intensity of ZLRs while the other three remained unchanged. There were nine cases featuring attachment of the distal, non-offending portion of offending vessels to the distal course of the facial nerve in addition to attachment to REZ. Negative ZLR conversion and presence of peripheral contact of offending vessels to distal facial nerves showed significant correlations (p < 0.05). ZLR could be elicited by electrical stimulation at non-REZ-offending portion of the offending arterial wall, attached to the distal course of the facial nerve. HFS disappeared immediately in all 20 patients.

CONCLUSIONS

Although ZLR might be helpful in cases with multiple offenders, interpretation of ZLR needs caution for non-specific transmission of electric current through vessel wall to facial nerve.

Hearing Loss following Posterior Fossa Microvascular Decompression: A Systematic Review

Objectives (1) Determine the prevalence of hearing loss following microvascular decompression (MVD) for trigeminal neuralgia (TN) and hemifacial spasm (HFS). (2) Demonstrate factors that affect postoperative hearing outcomes after MVD. Data Sources PubMed-NCBI, Scopus, CINAHL, and PsycINFO databases from 1981 to 2016. Review Methods Systematic review of prospective cohort studies and retrospective reviews in which any type of hearing loss was recorded after MVD for TN or HFS. Three researchers extracted data regarding operative indications, procedures performed, and diagnostic tests employed. Discrepancies were resolved by mutual consensus. Results Sixty-nine references with 18,233 operations met inclusion criteria. There were 7093 patients treated for TN and 11,140 for HFS. The overall reported prevalence of hearing loss after MVD for TN and HFS was 5.58% and 8.25%, respectively. However, many of these studies relied on subjective measures of reporting hearing loss. In 23 studies with consistent perioperative audiograms, prevalence of hearing loss was 13.47% for TN and 13.39% for HFS, with no significant difference between indications ( P = .95). Studies using intraoperative brainstem auditory evoked potential monitoring were more likely to report hearing loss for TN (relative risk [RR], 2.28; P < .001) but not with HFS (RR, 0.88; P = .056). Conclusion Conductive and sensorineural hearing loss are important complications following posterior fossa MVD. Many studies have reported on hearing loss using either subjective measures and/or inconsistent audiometric testing. Routine perioperative audiogram protocols improve the detection of hearing loss and may more accurately represent the true risk of hearing loss after MVD for TN and HFS.

Long-term surgical results in microvascular decompression for hemifacial spasm: efficacy, morbidity and quality of life

Hemifacial spasm is a condition that may severely reduce patients' quality of life. Microvascular decompression is the neurosurgical treatment of choice. The objective of this work was to describe the efficacy and morbidity of microvascular decompression for hemifacial spasm, evaluate the long-term efficacy on the quality of life and investigate prognostic factors for failure of the procedure. A retrospective study of 446 cases of hemifacial spasm treated by 511 retrosigmoid microvascular decompression over 22 years was conducted. Epidemiological, clinical and imaging findings, treatment modalities and outcomes of patients with pre- and postoperative HSF-8 quality of life questionnaire were studied. Success rate was 82% after first surgery and 91.6% after revision surgery. A low rate of perioperative morbidity was found. Facial palsy was mostly transient (5.5% transient and 0.2% permanent) and cochleovestibular deficit was seen in 4.8% of patients. Revision surgery increased nervous lesions (10.6% to 20.7%). Mean quality of life scores were significantly improved from 18 to 2 over 32, evaluated 7.3 years after surgery. Predictive factors of surgical failure were single conflicts (p = 0.041), atypical vasculo-nervous conflicts involving other vessel than postero-inferior cerebellar artery (p = 0.036), such as vein (p = 0.045), and other compression sites than root exit zone (p = 0.027). Retrosigmoid microvascular decompression is a safe and effective treatment of hemifacial spasm. Revision surgery is not to be excluded in case of failure, but does place patients at risk for more complications. Quality of life is improved in the long-term, indicating objective and subjective satisfaction.