Microvascular Decompression Surgery Research Articles

Facial Nerve Massage for the Treatment of Hemifacial Spasm Refractory to Microvascular Decompression: Outcomes and Complications.

After microvascular decompression (MVD) for hemifacial spasm (HFS), a minority of patients realize little to no relief of spasms. In some patients, the absence of relief of spasms results from incomplete or inadequate decompression of vascular compression of the facial nerve, and these patients represent excellent candidates for repeat MVD. However, in other patients, repeat MVD is not appropriate because adequate decompression and resolution of neurovascular compression, as determined by postoperative high-resolution MRI, was achieved with the initial operation. To present a cohort of patients with a history of HFS refractory to MVD, with no evidence of neurovascular compression on postoperative MRI, who underwent facial nerve massage (FNM) in the posterior fossa in an attempt to relieve spasms. Thirteen patients with a history of incomplete relief of spasms after technically adequate MVD surgery for hemifacial spasm underwent FNM. Immediate and long-term degree of spasm relief and complications after FNM were documented through in-person or telemedicine interview. At follow-up after FNM, 7 of 12 patients (58.3%) reported complete spasm relief (grade I), 2 of 12 patients (16.7%) reported >75% spasm relief (grade II), 0 patient (0%) reported >50% spasm relief (grade III), 3 of 12 (25.0%) patients reported <50% spasm relief (grade IV), and 1 patient was lost to follow-up. One patient experienced a delayed facial paresis, and another patient experienced high-frequency hearing loss. After FNM, durable and, at least, partial relief of spasms with a relatively low complication rate was observed in most patients with HFS with incomplete relief of spasms after technically adequate prior MVD.

A single centre case series of microvascular decompression surgery for classical trigeminal neuralgia: functional outcomes and report of a unique conflict

BackgroundMicrovascular decompression surgery for trigeminal neuralgia is now considered the benchmark surgical procedure for intractable trigeminal neuralgia of any variety. The objective of this study is to share our experience in managing classical trigeminal neuralgia with microvascular decompression surgery looking into both immediate and late functional outcomes at 3 and 6 months post op. We also report a unique case of trigeminal neuralgia due to a tributary of the petrosal vein passing through the substance of the trigeminal nerve itself at its root entry zone.ResultsThis study included 20 patients; it showed that microvascular decompression surgery of the trigeminal nerve is an effective method for treatment of classic trigeminal neuralgia (p value < 0.001). The trigeminal root was compressed by the superior cerebellar artery in 75% of patients. A vein contributed to the compression in 45% of patients and was the only compressing vessel in 15%.ConclusionMicrovascular decompression surgery is the treatment of choice in patients with medically refractory trigeminal neuralgia, unless their general condition prohibits it. It’s also worth noting that the normal anatomy of the veins in this region is quite variable and the venous structures causing a neurovascular contact are more or less inconsistent. To the best of our knowledge and despite the wide range and progress in microvascular decompression surgery for trigeminal neuralgia, this is the first reported case in the literature for a neurovascular conflict caused by a vein passing through the trigeminal nerve itself.

Venous Flow Conversion Technique for Sacrificing the Superior Petrosal Vein During Microvascular Decompression for Trigeminal Neuralgia.

BACKGROUND:Microvascular decompression for trigeminal neuralgia (TN) may require sacrifice of the superior petrosal vein (SPV), with potential risks of ischemia and hemorrhagic complications due to impaired venous return.OBJECTIVE:To investigate methods for safely sacrificing the SPV.METHODS:We retrospectively reviewed 21 cases in 346 consecutive microvascular decompression surgeries for TN. They were intraoperatively identified as SPV and its tributaries being the offending vessels causing TN and were intentionally sacrificed.RESULTS:The transverse pontine vein (TPV) was sacrificed in 10 patients. The main trunk of the SPV was sacrificed using the TPV as a collateral flow pathway in 10 patients. No complications occurred related to impaired venous return.CONCLUSION:The venous flow conversion technique can be applied to safely sacrificing the SPV and its tributaries with the TPV acting as a collateral blood flow pathway to prevent postoperative impaired venous return.

Outcomes using linear accelerator stereotactic radiosurgery for the treatment of trigeminal neuralgia: A single-center, retrospective study.

Background: Linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) treatment of trigeminal neuralgia (TN) may have similar efficacy to Gamma Knife SRS (GK-SRS), but the preponderance of data comes from patients treated with GK-SRS. Our objective was to analyze the outcomes for LINAC-based treatment of TN in patients at our institution.Methods: We retrospectively analyzed data for patients who underwent LINAC-based SRS for TN from 2006 to 2018. Data were collected from the patients’ medical records. Nonparametric statistics were used for the analysis.Results: Of the 41 patients treated with LINAC-based SRS (typically 90 Gy dosed using a 4 mm collimator for one fraction) during that time, follow-up data of >3 weeks post-SRS were available for 32 patients. The median pretreatment Barrow Neurological Institute (BNI) pain score was 5 (range 4–5). The follow-up period ranged from 0.9 to 113.2 months (median 5 months). There was significant improvement in postradiation BNI pain score (P < 0.001), with 23 (72%) patients who improved to a BNI pain score of 1–3. One patient had bothersome hypoesthesia postradiation. Approximately 38% of patients who had initial pain control had recurrence of symptoms (BNI > 3). Survival analysis showed a median time to pain recurrence of 30 months. There was no relationship between prior microvascular decompression (MVD) surgery and change in BNI pain score pre- to posttreatment.Conclusion: The results demonstrate that LINAC-based SRS is an effective means to treat TN. Prior MVD surgery did not affect efficacy of SRS in lowering the BNI score from pre- to posttreatment in this patient cohort.

미세혈관감압술에서 뇌줄기청각유발전위의 최신지견

Hemifacial spasm (HFS) is due to the vascular compression of the facial nerve at its root exit zone (REZ). Microvascular decompression (MVD) of the facial nerve near the REZ is an effective and curative treatment for HFS. Since the cochlear nerve lies directly adjacent to the facial nerve, postoperative hearing loss frequently occurs during MVD surgery for HFS. However, the rate of postoperative hearing loss has decreased since introducing the intraoperative neurophysiologic monitoring (IONM) of brainstem auditory evoked potentials (BAEPs). There have been many advances on this field in the recent decade. This article aimed to review and present advances in IONM of BAEPs.

Diplopia following microvascular decompression surgeries: illustrative cases

BACKGROUNDMicrovascular decompression is an effective treatment strategy for trigeminal neuralgia. However, there may be inadvertent complications involving adjacent cranial nerves during or months after the operation. This case lesson highlights the potential manifestations, both optical and nonneurologic (monocular) and binocular diplopia, after microvascular decompression in two patients. Neurosurgeons should recognize monocular versus binocular causes of diplopia after neurosurgical microvascular decompression.OBSERVATIONSThe authors reported on two patients who presented with diplopia after microvascular decompression for trigeminal neuralgia. The first patient had binocular diplopia with a paradoxical head tilt potentially due to a contiguous trochlear nerve palsy. The second patient had monocular diplopia due to dry eye syndrome from trigeminal nerve dysfunction. However, within 2 years after their operations, both patients had resolution of their diplopia without additional surgical intervention.LESSONSBoth monocular and binocular diplopia can be presenting symptoms of cranial neuropathies after microvascular decompression for trigeminal neuralgia. Most cases of postoperative diplopia (both monocular and binocular) resolve spontaneously over time without additional neurosurgical treatment.

Association of intraocular pressure and postoperative nausea and vomiting after microvascular decompression - a prospective cohort study

BackgroundPostoperative nausea and vomiting is common in patients receiving microvascular decompression. In the current study, we examined whether postoperative nausea and vomiting is associated with reduced intraocular pressure (IOP) after microvascular decompression, a measure that reflects intracranial pressure.MethodsThis is a prospective cohort study. Adult patients scheduled for microvascular decompression surgery for hemifacial spasm between January 2020 and August 2020 were eligible. IOP was measured immediately before anesthesia induction and 30 min after patients regained complete consciousness using non-contact tonometry. IOP reduction was defined by at least 1 mmHg decrease vs. preoperative baseline. The primary outcome was vomiting on postoperative day 1.ResultsA total of 103 subjects were enrolled. IOP was reduced in 56 (54.4%) subjects. A significantly greater proportion of patients with IOP reduction had vomiting on postoperative day 1 (51.8% (29/56) vs. 23.4% (11/47) in those without IOP reduction; p = 0.003). In the multivariate regression analysis, vomiting on postoperative day 1 was associated with female sex [odds ratio = 7.87, 95% CI: 2.35–26.32, p = 0.001] and IOP reduction [odds ratio = 2.93, 95% CI: 1.13–7.58, p = 0.027].ConclusionsIn patients undergoing microvascular decompression surgery, postoperative IOP reduction is associated with postoperative vomiting.Trial registration:Chinese Clinical Trial Registry: ChiCTR2000029083. Registered 13 January 2020.

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.

A Novel Approach to Microvascular Decompression for Hemifacial Spasm: Method Description and Associated Outcomes.

Microvascular decompression (MVD) is the only potential cure for hemifacial spasm (HFS). However, traditional techniques such as the interposition method may have limited effect in some cases. Alternative techniques have been proposed; however, they can be more complex or difficult to perform than the standard approach. To describe a safe decompression technique-the "shelter method"-which involves creating a shelter-like space around the facial nerve root exit zone and present associated outcomes. Medical records and intraoperative findings of 92 patients with HFS who underwent MVD using the shelter method between April 1997 and March 2017 were retrospectively reviewed. As a historical control group, we included 53 patients who had undergone MVD by the traditional interposition method before March 1989. The patients were divided into 3 subgroups according to the arteries involved and degree or direction of arterial compression to the seventh nerve. Patient outcomes were assessed as excellent, good, fair, and poor according to the MVD scoring system of the Japan Society for MVD Surgery. In the shelter method group, complete disappearance of HFS was achieved in 87 patients (94.6%). The curative rate of the shelter method group was significantly higher than that of the interposition method group. The overall complication rates were significantly lower in the shelter method group than in the interposition method group. Our findings indicate high curative and low complication rates of the shelter method, suggesting that it helps treat HFS caused by various types of arterial compression.

Multidata Analysis Based on an Artificial Neural Network Model for Long-Term Pain Outcome and Key Predictors of Microvascular Decompression in Trigeminal Neuralgia

To investigate use of multidata analysis based on an artificial neural network (ANN) to predict long-term pain outcomes after microvascular decompression (MVD) in patients with trigeminal neuralgia (TN) and to explore key predictors. Perioperative and long-term follow-up multidata of 1041 patients with TN who received MVD surgery at Hangzhou First People's Hospital from March 2013 to May 2018 were collected to construct an ANN model for prediction. The prediction results were compared with the actual follow-up outcomes, and the variables in each input layer were changed to test the effectiveness of ANN and explore the factors that had the greatest impact on prediction accuracy. The ANN model could predict the long-term pain outcomes after MVD in patients with TN with an accuracy rate of 95.2% and area under the curve of 0.862. Four factors contributed the most to the predictive performance of the ANN: whether the neurovascular offending site of the trigeminal nerve corresponded the region of facial pain, immediate postoperative pain remission after MVD, degree of nerve compression by culprit vessels, and the type of culprit vessels. After these factors were sequentially removed, the accuracy of the ANN model decreased to 74.5%, 78.6%, 87.2%, and 90.1%, while the area under the curve was 0.705, 0.761, 0.793, and 0.810. The ANN model, constructed using multiple data, predicted long-term pain prognosis after MVD in patients with TN objectively and accurately. The model was able to assess the importance of each factor in the prediction of pain outcome.

Surgical Treatment for Trigeminal Neuralgia.

Various treatments for trigeminal neuralgia (TN) are known to yield initial satisfactory results; however, the surgical treatment has excellent long-term outcomes and a low recurrence rate. Surgical treatment addresses the challenge of vascular compression, which accounts for 85% of the causes of TN. As for surgical treatment for TN, microvascular decompression (MVD) has become the surgical treatment of choice after Peter J. Jannetta reported the results of MVD surgery in 1996. Since then, many studies have reported a success rate of over 90% for the initial surgical treatment. Most MVDs aim to separate (decompress) the culprit vessel from the trigeminal nerve. To increase the success rate of surgery, accurate indications for MVD and management of the offender vessels without complications are critical. In addition, if there is no vascular compression, partial sensory rhizotomy or internal neurolysis can be performed to improve surgical outcomes.

Microvascular Decompression for Hypoglossal Nerve Palsy Associated With Vertebral Artery: Case Report and Review of Literature

BACKGROUND AND IMPORTANCE: Hypoglossal nerve palsy is an infrequent condition that could be rarely caused by compression from nearing vasculature. Hypoglossal nerve palsy associated with vertebral artery (VA) is rarely reported. There are less than 15 cases of such conditions in the literature. CLINICAL PRESENTATION: We present a 17-year-old boy suffering from dysarthria, chewing disability, a tingling sensation, and deviation of the tongue to the right from 6 months ago. After a thorough examination, MRI was performed with clinical suspicion of hypoglossal nerve palsy, and the result showed an ectatic VA pressing against the right hypoglossal nerve. He underwent microvascular decompression surgery. On follow-up visits, he showed gradual improvement of symptoms. CONCLUSION: In cases of cranial nerve palsies, compression by adjacent vasculature should be considered as a differential diagnosis and microvascular compression should be considered as a safe definitive treatment.

Prognostic Value of Lateral Spread Response Recorded 1 Month After Microvascular Decompression for the Treatment of Hemifacial Spasm.

The predictive value of intraoperative disappearance of the lateral spread response (LSR) during microvascular decompression surgery for hemifacial spasm treatment is unclear. Studies evaluating the clinical implications of the LSR recorded during the postoperative period are also limited. To analyze the LSR 1 month postoperatively and to evaluate its prognostic value until 1 year postsurgery. In total, 883 patients who underwent microvascular decompression between 2016 and 2018 were included. LSR was recorded preoperatively, intraoperatively before decompression, intraoperatively after decompression, and 1 month postoperatively. The outcomes were evaluated at 1 week, 1 month, and 1 year postoperatively. The presence of preoperative and intraoperative LSR after decompression did not predict the postoperative outcome at 1 year. In 246 patients (27.9%), the postoperative LSR at 1 month was not identical to that recorded intraoperatively after decompression. Postoperative LSR at 1 month was associated with a worse outcome at 1 month (P < .0001) and 1 year (P = .0002) postoperatively. Patients with residual symptoms and a LSR 1 month postoperatively were more likely to show residual symptoms 1 year postoperatively, with a positive predictive value of 50.7%. Unlike the intraoperative LSR, the LSR at 1 month postoperatively showed prognostic value in predicting 1-year postoperative outcomes and was useful for identifying patients with a high risk of unfavorable outcomes. Thus, confirming the presence of postoperative LSR is necessary.

Risk factors of herpes simplex virus reactivation after surgery for primary trigeminal neuralgia

The objective of this study is to investigate the risk factors of oral or facial herpes simplex virus (HSV-1) infection after primary trigeminal neuralgia (PTN). The clinical data of 33 PTN patients admitted by the same surgeon in the neurosurgery were retrospectively analyzed. Among the 33 patients, 26 patients underwent microvascular decompression (MVD), 6 patients who have not been found the clear offending vessels during the operation underwent partial sensory rhizotomy (PSR), and only one underwent adhesive band separation. Thirteen patients with postoperative oral and facial HSV-1 infection were selected as the herpes group, and the remaining 20 patients without postoperative oral and facial HSV-1 infection were selected as the non-herpes group. The differences between the two groups were compared by statistical analysis of factors such as gender, age, operation mode, operation time, and serum HSV-1 antibody titer value before surgery. Compared with the non-herpes group, there were no statistically significant differences in sex ratio (P = 0.930), age composition (P = 0.261), or disease profile (P = 0.226). Twenty-six patients underwent MVD operation, eight of whom were infected, and the difference between the two groups was statistically significant (P = 0.029). The operation time of the herpes group was 10-30min, which was significantly longer than that of the non-herpes group. The difference in operation time between the two groups was statistically significant (P = 0.023). Serum HSV-1-IgM was negative (< 0.9 COI) in all patients before surgery, but the positive rate of HSV-1-IgG (≥ 1.1 COI) was 97%, and the titer was greater than four times in 97% (32/33) of patients. The titer of IgG antibody in the herpes group was significantly lower than that in the non-herpes group, and the difference between the two groups was statistically significant (P = 0.017). The serum HSV-1-IgG in most of the PTN patients was positive. Latent HSV-1 in the trigeminal ganglion may be reactivate after PTN surgery to produce ipsilateral oral and facial herpes infection. The infection of HSV-1 reactivation after PTN surgery was positively correlated with the operation time but negatively correlated with the titer of HSV-1-IgG antibody before PTN surgery. The incidence of HSV-1 infection after PTN operation is related to different surgical procedures.

Application of ABR in pathogenic neurovascular compression of the 8th cranial nerve in vestibular paroxysmia

PurposeTo investigate the clinical value of electrophysiological tests in indicating pathogenic vascular contact of the 8th nerve in definite vestibular paroxysmia (VP) cases to provide a reference for decompression surgery.MethodsWe retrospectively analyzed patients who had vertigo, unilateral tinnitus, or hearing loss and exhibited vascular contact of the 8th cranial nerve by MRI. Participants were classified into the VP or non-VP group according to the criteria of the Bárány Society in 2016. The demographic characteristics and audiological and electrophysiological test results of the two groups were compared. Receiver operating characteristic (ROC) curves were calculated for ABR to determine the best parameters and cutoff values to predict the existence of pathological neurovascular contact in VP.ResultsThirteen patients in the VP group and 66 patients in the non-VP group were included. VP patients had longer interpeak latency (IPL) I–III and wave III latency compared to non-VP patients (p < 0.001; p < 0.001). According to the ROC analyses, IPL I–III and wave III latency were the best indicators for the diagnosis of VP. The optimal cutoff for IPL I–III was 2.3 ms (sensitivity 84.6%, specificity 95.5%), and that for wave III latency was 4.0 ms (sensitivity 92.3%, specificity 77.3%). There were no differences in the PTA, caloric test, o-VEMP, or c-VEMP results between the two groups.ConclusionProlonged IPL I–III and the wave III latency of ABR strongly suggested that vascular contact of the 8th cranial nerve was pathological, which may provide some references for microvascular decompression surgery of VP.

Treatment Strategies for Different Types of Intraneural Offending Vessels in Microvascular Decompression Surgery for Trigeminal Neuralgia: An Analytic Report of 58 Cases.

Microvascular decompression (MVD) surgery is the treatment of choice for trigeminal neuralgia (TGN). However, decompression becomes difficult when the offending vessel penetrates the trigeminal nerve root. To estimate the rates and patterns of different types of intraneural offending vessels in patients with TGN for MVD and to discuss respective management strategies. All patients with TGN undergoing MVD in our center from January 1, 2015, to December 31, 2019, were analyzed retrospectively. The intraneural offending vessels included veins and arteries. The postoperative pain relief rate, complications, and recurrences were evaluated. Of the 302 TGN cases, the intraneural offending vessels were identified in 58 of the cases (19.2%). The 9 cases (15.5%) of intraneural offending arteries were decompressed using shredded Teflon wrapping interposition. Of the 49 cases (84.5%) of intraneural offending veins (INOVs), 29 were not considered true offending vessels, and the treatment only addressed the offending artery in these patients. Of the remaining 20 INOVs, 15 were electrocoagulated and divided, and 5 were decompressed with shredded Teflon. Complete pain relief was achieved in all 58 patients. However, the pain recurred in 5 patients (8.6%), and transient hemifacial numbness occurred in 4 patients (6.9%). Intraneural offending vessels requiring treatment are uncommon and are seen in less than 1 in 10 patients undergoing MVD for TGN. For intraneural offending artery, decompression by shredded Teflon wrapping interposition is recommended. Management of the INOV depends on the individual situations, and the management includes sacrifice, wrapping decompression, or leaving them untreated.

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

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. 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). 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. 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.

Predictive and prognostic factors for outcome of microvascular decompression in trigeminal neuralgia.

Trigeminal neuralgia (TN) is a disease characterized by recurring, short-lived, electric shock-like pain experienced on one side of the face. Microvascular decompression (MVD) is one of the most effective surgical interventions for resolving TN caused by neurovascular compression. This study aimed to determine the predictive and prognostic factors of surgical outcomes. This retrospective cohort study enrolled patients diagnosed with TN who underwent MVD at our hospital during 2013-2019. The demographic information, pain character, peri-operative Barrow Neurological Institute (BNI) scale, medication, operative finding were recorded. And the outcome was Outcomes were divided into drug-free and drug-dependent group. Predisposing factors for each outcome were analyzed by one-way analysis of variance, followed by a Mann-Whitney U test or Kruskal-Wallis test. A total of 104 consecutive patients received MVD to treat TN, and 88 patients were enrolled in this study. The overall postoperative drug-free outcome was 72.7%. A significant difference in drug-free outcomes was observed for patients with typical TN (80.8%) compared with patients with atypical TN (33.33%, p = 0001). When severe venous compression was encountered during MVD, the drug-free outcome fell to 50% (10/20, p = 0.009). The Mann-Whitney U test indicated typical TN as a positive predictive factor of a drug-free outcome, whereas severe venous compression was a negative predictive factor. The patients with preoperative BNI score of 4 had better improvement than others (p = 0.045). Age, onset duration, and arterial loop had no specific difference in this study. In our study, atypical TN and severe venous compression were associated with poor outcomes. Regrouping atypical TN into precise diagnosis represents an immediate priority according to our result. The preoperative BNI score could be used as an effective predictive tool for the outcome of MVD surgery.

The outcome of microvascular decompression for hemifacial spasm: a systematic review and meta-analysis.

Microvascular decompression (MVD) is the first choice of surgery for hemifacial spasm (HFS). MVD surgery for vertebral artery (VA)-associated HFS is more difficult than for non-VA-associated HFS. There is controversy about the cure rate and complication of MVD for HFS in previous studies. We searched PubMed, Web of Science, and Embase for relevant publications. Based on the search results, we compared the outcomes of MVD for VA-associated HFS and non-VA-associated HFS. At the same time, we analyzed spasm-free rates and the complications and assessed the relationship between VA-associated HFS and gender, left side, and age. For analysis, six studies that included 2952 patients in the VA-associated group and 604 in the non-VA-associated group were selected. The effective rate of MVD was not significantly different between both groups (OR = 1.16, 95% CI 0.81-1.67, P = 0.42). Compared to non-VA-associated group, the transient complications (OR = 0.64, 95% CI 0.46-0.89, P = 0.008) and permanent complications (OR = 0.28, 95% CI 0.15-0.54, P = 0.0001) occurred more frequently in VA-associated group. The rate of hearing loss was significantly higher in VA-associated HFS than non-VA-associated HFS (OR = 0.35, 95% CI 0.19-0.64, P = 0.0007); the facial paralysis after operation was not significantly different between both groups (OR = 1.25, 95% CI 0.91-1.72, P = 0.17). There were older patients (WMD = 3.67, 95% CI 3.29-4.05, P < 0.00001) and more left-sided HFS (OR = 0.23, 95% CI 0.19 - 0.29, P < 0.0002) in the VA-associated HFS group than non-VA-associated HFS group, while the non-VA-associated HFS group was female-dominated (OR = 1.58, 95% CI 1.32 - 1.89, P < 0.00001). Both groups achieved good results in MVD cure rates. In VA-associated HFS, the complication rate of decompression and the rate of hearing loss after operation were higher than in non-VA-associated HFS, but the facial paralysis after operation was similar in both groups, and most complications were transient and disappeared during follow-up. VA-associated HFS is more prevalent in older adults, less prevalent in women, and more predominantly left-sided. More clinical studies are needed to better compare the efficacy and complication of MVD between both groups.

Analysing Correlation Between the Facial Nerve Notch at the Root Exit Zone and Long-term Effect in Patients with Hemifacial Spasm After Microvascular Decompression: A Prospective Study.

Microvascular decompression (MVD) has become widely accepted for hemifacial spasm (HFS). The significance of facial nerve notch (FNN) for the outcome after MVD is still unknown. To investigate the correlative analysis between the FNN at the root exit zone (REZ) and the curative effect of MVD for HFS. A prospective study was performed, which included 232 patients with Cohen score ≥2 who had undergone MVD. The patients were divided into two groups: the group with facial nerve notch (FNN) and the group without FNN, according to whether there is FNN caused by the offending vessels during the MVD operation. All the patients were followed up for 24 months. The group with FNN caused by offending vessels at the REZ area was confirmed in 119 patients, of which 117 patients were immediately cured and two patients received partial relief on the 1st day of postoperation. The group without FNN at the REZ area was confirmed in 113 patients, of which 43 patients were immediately completely cured while 70 patients were not immediately completely cured after MVD operation. After 24 months of follow-up, 119 patients with FNN were all completely cured, 71 patients without FNN were completely cured, and 42 patients without FNN were not completely cured. Multivariate logistic regression analysis shows that compared with without FNN group, the FNN group had statistical significance for the clinical results both on the-1st -day (P < 0.01) and 2 years of follow-up (P < 0.05) after MVD operation. FNN is an important reference factor to evaluate both the short-term and long-term curative effect of microvascular decompression for hemifacial spasm. The postoperative effect of patients with FNN is much better than that of patients without FNN.