Long-term results of microvascular decompression for trigeminal neuralgia and hemifacial spasms according to preoperative symptomatology

Background

Microvascular decompression (MVD) is currently used in several centres for the treatment of trigeminal neuralgia (TN) and hemifacial spasms (HFS). How long-term results relate to the preoperative symptoms still needs to be documented. The primary aim of this study was to assess long-term results of MVD for TN and HFS, as related to the types of preoperative symptoms.

Methods

We performed a retrospective study including all first-time MVDs for TN and HFS done during the 11-year period (1999–2009) in the Department of Neurosurgery, The National Hospital (Rikshospitalet), Oslo. The patients were categorized depending on the pre-operative symptomatology.

Results

The study population includes 303 first-time procedures performed by the senior author (PKE), 243 TN patients (65 % TN without constant pain and 35 % TN with constant pain) and 60 HFS patients (95 % typical HFS and 5 % atypical HFS). The patients were followed for a mean 71 months (range, 14–147). In both the TN and HFS patients, MVD caused lasting symptom relief in a high proportion of patients, including patients with atypical symptoms.

Conclusion

After MVD for TN and HFS, regardless of preoperative symptoms, lasting relief is observed in a high proportion of patients, with a favorable complication profile.     

Microvascular decompression for neurovascular conflicts in the cerebello-pontine angle: which role for endoscopy?

Background

Microvascular decompression (MVD) is the surgical intervention designed to resolve neurovascular conflicts (NCs) in the cerebellopontine angle (CPA). Today, endoscopy is commonly used in many neurosurgical procedures. This study aims to retrospectively assess the usefulness of endoscopy during MVD, focusing on microscopic endoscopic-assisted (MEA) MVD.

Methods

Between January 2010 and December 2012, 141 patients underwent MVD procedures: 119 (84.5 %) were affected by idiopathic trigeminal neuralgia (TN), 20 (14 %) by hemifacial spasm (HFS), 1 by glossopharyngeal neuralgia (GN) and 1 by TN and GN simultaneously; 128 (91 %) MVD were first time procedures, while 13 (9 %) were recurrences (10 TN, 3 HFS). Visualization techniques used were: pure microscopic in 89 (63 %) cases, fully endoscopic in 12 (8.5 %) and MEA in 40 (28.5 %). The MEA technique was used when the conflict was not clearly identified under microscopic view or it was not certainly resolved.

Results

Overall, a NC was found in 130 (92 %) cases, while 11 patients had no intraoperative evidence of NC. Considering specifically the 40 MEA cases, 12 (8.5 % overall) conflicts not clearly visible with the microscope were revealed and solved, a complete conflict resolution was confirmed in 13 (9 % overall) cases, while an incomplete conflict resolution was shown in four cases (3 % overall).

Conclusion

Pure microscopic MVD remains the technique of choice. The endoscope is a useful adjunctive imaging tool in confirming NCs identified by the microscope, revealing conflicts missed by the microscopic survey alone and verifying adequate nerve decompression.     

Usefulness of the endoscope in microvascular decompression for trigeminal neuralgia and MRI-based prediction of the need for endoscopy

Background

Microvascular decompression (MVD) is a documented effective treatment of trigeminal neuralgia (TN). Lately, reports on endoscopy-assisted microvascular decompression (eaMVD) with better outcome and less risk have emerged. This study was undertaken to verify under which circumstances the endoscope proved essential in identifying the neurovascular conflict (NVC) during eaMVD for TN, and to assess the possibility to predict the need for the endoscope on preoperative magnetic resonance imaging (MRI).

Methods

Retrospective analysis of 97 patients with TN undergoing eaMVD at the Oslo University Hospital – Rikshospitalet, 1999–2009. To assess the NVC and anatomical variations, surgical reports were evaluated. MRI was available in 66 patients. The MRIs were evaluated by a blinded neuroradiologist.

Results

In 27 of the 97 patients (27.8 %), the endoscope was a significant aid in identifying the NVC, due to a bony ridge obscuring the view of the fifth nerve, a very distal vascular compression, or a combination of both. The preoperative MRI over-diagnosed the presence of a bony ridge. However, the MRI-based fraction of microscopically visible trigeminal nerve (FVN) in the cerebellopontine angle cistern proved diagnostic (ROC curve, AUC 0.89, p?=?<0.001) with an optimal cut-off value of 0.35. Hence, if less than 35 % of the trigeminal nerve is visible on preoperative MRI, the endoscope will be needed to identify the NVC.

Conclusions

The endoscope is a valuable tool during MVD for TN, especially under anatomical circumstances such as a bony ridge hiding the direct microscopic view of the NVC. These anatomical circumstances can be predicted with good accuracy on preoperative MRI.     

Management of symptomatic hemifacial spasm or trigeminal neuralgia

Hemifacial spasm (HFS) or trigeminal neuralgia (TN) is a kind of hyperactivity disorder of cranial nerves caused by vascular compression. However, sometimes, the disease may arise from nerve damage produced by tumors, which was called as symptomatic HFS/TN. Until now, little is known about the exact mechanism and the necessity of microvascular decompression (MVD) regarding the tumor-induced HFS/TN, which is necessary to be retrospectively analyzed in a considerable sample. Among the 4021 patients who underwent MVD in our department between 2006 and 2014, 44 were finally diagnosed as symptomatic HFS or TN. These patients were focused in this study and their clinical features as well as intraoperative findings and postoperative outcomes were retrospectively investigated. Data analysis exhibited the symptomatic HFS/TN cases accounted for 1.1 % in the study, which were caused by epidermoid in 18 (40.9 %) and meningioma in 15 (34.1 %) followed by neuroma in 7 (15.9 %) as well as aneurysm in 2 (4.5 %) and arteriovenous malformation in 2 (4.5 %). Compared to those with idiopathic HFS/TN, younger females were more susceptible (p?<?0.05). After resection of the neoplasm, the offending vessel was identified in 26 (59.1 %), which were followed by MVD process. Postoperatively, the symptoms relief rate was 88.6 %. Our study showed that surgical management of patients with symptomatic HFS/TN may lead to a satisfactory result, yet those primary lesions should be removed firstly. In some cases, a microvascular decompression process might be unnecessary afterward, but the entire nerve root should be checked to exclude any vessel in contact with.     

Validation and evaluation of the volumetric measurement of cerebellopontine angle cistern as a prognostic factor of microvascular decompression for primary trigeminal neuralgia

Background

The aim of this study was to analyze the prognostic factors of trigeminal neuralgia (TN) after microvascular decompression (MVD), and to evaluate the volumetric parameters of the cerebellopontine angle (CPA) cistern as a pathogenic factor and imaging predictor.

Methods

This retrospective study included 70 patients with primary TN treated with pure MVD, followed up for at least 1 year and evaluated by high-resolution MR imaging. The volume of the CPA cistern was calculated bilaterally, and the “Cistern Deviation Index” was defined to represent degree of deviation of the CPA cistern. Clinical data and volumetric parameters were compared between patients with TN and age- and sex-matched controls without TN, and between the recurrent and non-recurrent patients.

Results

The transposition procedure had a better outcome than the interposition procedure (P?<?0.001). There was a significant difference in the volume of CPA cistern between the affected and unaffected side (152.1?±?50.1 vs. 179.9?±?63.7 mm³, P?<?0.001) in patients with TN, while no significant difference between the right and left side (158.7?±?44.6 vs. 163.1?±?49.8 mm³, P?=?0.162) in controls. The Cistern Deviation Index was significantly larger in controls than in patients with TN (P?=?0.048), and in the non-recurrent patients than in recurrent patients (P?=?0.040).

Conclusion

We demonstrated that the volumetric parameters of the CPA cistern are a marker for understanding the pathogenesis of TN and useful for predicting the recurrence after MVD. The Cistern Deviation Index might contribute to deciding the surgical approach.     

Neuralgias of the lower cranial nerves: microsurgical posterior fossa exploration

Neuralgias of the lower cranial nerves are trigeminal neuralgia (TN), glossopharingeal neuralgia (GphN), and geniculate neuralgia (GN). Microsurgical posterior fossa exploration with its variations microvascular decompression (MVD), partial sensory rhisotomy (PSR), and total sensory rhisotomy (TSR) is one of the most efficient ways of treating these neuralgias. It was performed 130 operations in 125 patients with TN, 3 in GphN patients, 1 in GN patient, 1 in GN/TN patients, 1 in GphN/GN patient, and 2 in GN/hemifacial spasm patients. Of total of 125 patients with TN, MVD was performed in 63, PSR in 18, and MVD+PSR in 44 cases. In 5 patients with recidivate TN PSR was performed. Of total 3 patients with GphN MVD was performed in 2 cases, and extirpation of a small meningeoma in 1 case (it was not seen on CT). In the patients with GN TSR of intermediate nerve was performed, in GN/TN patients TSR of intermediate nerve and PSR of trigeminal nerve was performed, in the GN/GphN patients MVD of glossopharingeal and TSR of intermediate nerve were performed, and in the GN/hemifacial spasm patients TSR of intermediate and MVD of facial nerve were performed. The results of TN patients are: excellent in 82.4%, good in 12%, and poor in 5.6% of patients. There is no difference in complete pain relief, rate of recurrence, and complications between MVD, MVD+PSR and PSR operative groups (p0.05). Among patients with other neuralgias the following results are noted: excellent in 4, good in 3, and poor in 1 patient. Microsurgical posterior fossa exploration is the method of choice in the treatment of the neuralgias of the lower cranial nerves.     

A proposal for standardized analysis of the results of microvascular decompression for trigeminal neuralgia and hemifacial spasm

Background

The purpose of this study was to evaluate and analyze overall postoperative results from microvascular decompression (MVD) by combining the cure rate of symptoms with the complication rate. A new scoring system for obtaining objective surgical results from MVD for trigeminal neuralgia (TN) and hemifacial spasm (HFS) is proposed to document treatment results using consistent criteria in a standardized manner.

Method

Surgical results combining complications , if any, were obtained from a questionnaire sent to patients who had undergone surgery for TN or HFS in recent years and had been followed-up for more than 1?year after surgery (TN patients, n?=?54; HFS patients, n?=?81) When surgical outcome is complete resolution of symptoms, the efficacy of surgery (E) is designated E-0, but when moderate symptoms are still persist postoperatively, the score is designated E-2. When no complications are seen after surgery, the complication score (C) is C-0, while the score is C-2 if troublesome complications remain. In addition, total evaluation of the results (T) is judged by combining the E and C scores. For example, when E is 0, and C is C-2, the total evaluation is scored as T-2, which is diagnosed as fair.

Findings

The response rate of the questionnaire was 80.7% (109/135). Overall surgical data were evaluated and analyzed using our new scoring system. Analysis of the collected data revealed an outcome of T-0 was 70% (35/50 patients) and T-1 was 24% (12/50) and T-2 was 6% (3/50) in TN, whereas in HFS, T-0 was 61% (36/59) and T-1 was 27.1% (16/59) and T-2 was 6.8% (4/59) and T-3 was 5.1% (3/59).

Conclusion

The total results of MVD should be evaluated and analyzed by combining the cure rate of symptoms together with the complication rate. This new scoring system could allow much more objective analysis of the results of following MVD. Adopting this scoring system to objectively judge treatment results for TN and HFS, individual surgeons can compare their own overall surgical results with those of other institutes. Comparative results of MVD can also be provided to patients considering therapy to allow informed decision-making on the basis of good quality evidence.     

Intraoperative indocyanine green angiography during microvascular decompression surgery: report of 30 cases

Background

The purpose of this study was to evaluate the use of intraoperative indocyanine green (ICG) angiography during microvascular decompression (MVD) surgery.

Methods

The surgical outcomes of 19 patients with hemifacial spasm, nine patients with trigeminal neuralgia, and two patients with glossopharyngeal neuralgia who were treated with MVD surgery, using the posterior approach and routine craniotomy, via procedures in which ICG angiography was used were analyzed retrospectively.

Results

ICG angiography clearly displayed the nerves and blood vessels. Among the 30 patients, 25 were cured, four showed improvements, and one had a worsened outcome. There were no significant complications. Outcome was not associated with age, gender, or diagnosis.

Conclusion

Intraoperative ICG angiography used during MVD surgery provided a clear display of the nerves and arteries. All but one patient was cured or had improvement. The findings suggest that intraoperative ICG angiography may be an effective supplemental technique for use during MVD surgery.

     

The role of the cerebellopontine angle cistern area and trigeminal nerve length in the pathogenesis of trigeminal neuralgia: a prospective case-control study

Background

The aim of this prospective study was to evaluate whether the cerebellopontine angle (CPA) cistern area and trigeminal nerve cisternal length play a role in the pathogenesis of trigeminal neuralgia (TN).

Methods

High-resolution 1.5 T magnetic resonance imaging of the posterior fossa was performed in 26 patients with TN and 18 age-matched healthy controls. Axial T2-weighted, three-dimensional constructive interference in steady-state (3D-CISS) was used to measure bilaterally the cross-sectional area of the CPA cistern and trigeminal nerve cisternal length.

Results

In patients, the cross-sectional area of the CPA cistern and trigeminal nerve cisternal length was smaller on the affected side (p?=?0.04). Healthy controls tended to have larger cisternal areas and longer trigeminal nerve lengths than patients (p?=?0.059, p?=?0.071, respectively). Larger CPA cisternal areas tended to be seen in older patients. There was a strong correlation between the cross-sectional area of the CPA cistern and the length of the trigeminal nerve (p?=?0.000).

Conclusions

Smaller CPA cisterns and short cisternal trigeminal nerves impact the pathogenesis of essential TN by facilitating the neurovascular conflict, especially in younger patients. Trigeminal nerve cisternal measurement provides an easy and direct estimation of the CPA area. This information can be used for surgical planning and potentially for outcome prediction.     

Re-operation for persistent hemifacial spasm after microvascular decompression with the aid of intraoperative monitoring of abnormal muscle response

Background and objectives

Microvascular decompression (MVD) is the only solution that can effectively control hemifacial spasm (HFS). Regarding treatment of the patients who failed the first operation, it is still controversial. We tried to evaluate the safety and efficiency of the early re-exploration for such kinds of patients.

Methods

Thirteen patients failed the first MVD and received a second MVD procedure. The spasm was not resolved at all or became even more severe after the first MVD. Abnormal muscle response (AMR) persisted during the first MVD operation or disappeared once but emerged again. The patient had a strong will to do the re-operation and was aware of the high risks of operative complications.

Results

All the 13 patients got good or excellent spasm resolution immediately after the re-operation, which involved whole-range exploration and intraoperative AMR monitoring; however, there were two cases (15.4%) of permanent facial weakness and three cases (23.0%) of transient facial weakness.

Conclusions

Our experience on early repeat MVD is whole-range exploration and intraoperative AMR monitoring; in other words, re-operation cannot rely too much on experience.     

Stitched sling retraction technique for microvascular decompression: procedures and techniques based on an anatomical viewpoint

The success of microvascular decompression (MVD) depends on the permanent and complete transposition of the offending vessels. This paper describes the stitched sling retraction techniques for treating trigeminal neuralgia (TN), hemifacial spasm (HFS), and glossopharyngeal neuralgia (GPN), focusing on the stitching point for slinging the offending artery in the appropriate direction. Between January 2007 and March 2009, 28 patients with TN, 5 patients with HFS, and 3 patients with GPN underwent MVD with a sling retraction technique. In cases of TN, MVD was performed using the infratentorial lateral supracerebellar approach, and the offending superior cerebellar artery was superomedially transposed with a sling stitched to the tentorium cerebelli. In cases of HFS, MVD was performed using the lateral suboccipital infrafloccular approach, and the offending vertebral artery was superolaterally transposed with a sling stitched to the petrous dura. In cases of GPN, MVD was performed using the transcondylar fossa approach, in which the posterior inferior cerebellar artery was inferolaterally mobilized with a sling secured to the jugular tubercle. No patient suffered recurrence in the follow-up period. For the sling retraction technique to be performed successfully, it is important for a stitch to be placed at a suitable site to sling the offending vessel in the intended direction. An appropriate surgical approach must be used to obtain a sufficient operative field for performing the stitching procedures safely.     

Ectopic choroid plexus associated with trigeminal neuralgia: case report

Introduction

A 55-year-old man underwent a microvascular decompression procedure for a pharmacoresistant trigeminal neuralgia. Preoperative MRI showed a neurovascular conflict between the Vth nerve root and the superior cerebellar artery.

Methods

Dissection of the intracisternal trigeminal root was undertaken, and a piece of Teflon was positioned between the artery and the nerve.

Results

Choroid plexus was found squeezing the root entry zone of the Vth nerve and partially removed. The patient did not improve after the vascular decompression procedure. Trigeminal neuralgia could be due to a mechanical irritation of the intracisternal nerve root.

Conclusion

Since vascular decompression of the trigeminal root did not relieve the pain, we suggest that the presence of choroid plexus at the root entry zone of the nerve may have induced trigeminal neuralgia in this patient.     

Microvascular decompression of the root emerging zone for hemifacial spasm: evaluation by fusion magnetic resonance imaging and technical considerations

Object

The root exit zone (RExZ) of the facial nerve has been considered to be the target in microvascular decompression (MVD) for hemifacial spasm. However, more proximal segments with oligodendrocyte-derived myelin, where the facial nerve root emerges at the pontomedullary sulcus and adheres to the brainstem surface (root emerging zone [REmZ]), may also be susceptible to neurovascular compression. This study evaluated the predictive value of magnetic resonance (MR) imaging in detecting and assessing the features of vascular compression, especially in the pontomedullary sulcus, and describes the technical considerations of MVD procedures for the more proximal segments of the facial nerve.

Methods

Twenty patients treated with MVD underwent three-dimensional constructive interference in steady-state MR imaging and three-dimensional time-of-flight MR angiography. Their fusion images were used to evaluate the anatomical neurovascular relationships and intraoperative findings were analyzed.

Results

Most offending arteries at the REmZ and the RExZ of the facial nerve were correctly identified by fusion MR imaging. During surgery, neurovascular contacts were identified at one or more segments of the facial nerve in all patients. The REmZ of the facial nerve was affected in 55 % of the patients. The most common offending vessel at the REmZ was the posterior inferior cerebellar artery rather than the anterior inferior cerebellar artery. The key procedure to explore the deep-seated REmZ in the pontomedullary sulcus was full dissection of the lower cranial nerves to the brainstem origin.

Conclusions

Our definition more correctly describes the specific anatomical relationship of the facial nerve origin from the brainstem and the clinically relevant target for MVD surgery. Fusion MR imaging is very useful to identify neurovascular contacts at both the RExZ and the REmZ of the facial nerve.     

The cranial nerve vascular compression syndrome: I. A review of treatment

The author reviews current literature on microvascular decompression (MVD) for treatment of hemifacial spasm (HFS) and trigeminal neuralgia (TN), which shows that MVD is an effective treatment for these disorders. Although there are treatments for TN other than MVD that demonstrate a high rate of success, MVD is the only effective long-term treatment for HFS. MVD is also an effective treatment for glossopharyngeal neuralgia (GPN), and recently MVD has been shown to be an effective treatment for particular types of vertigo (disabling positional vertigo, DPV) and certain types of tinnitus.     

The long-term outcome of nerve combing for trigeminal neuralgia

Background

The purpose of our study was to describe and evaluate the long-term clinical outcome of nerve combing for idiopathic trigeminal neuralgia (TN) with and without vascular compression.

Methods

The study included 60 trigeminal neuralgia patients, 28 of which (Group A) had no visible vascular compression intraoperatively and 32 of which (Group B) had trigeminal nerve root entry zone (REZ) compressed by vascular structure. All patients were considered medical failures prior to the surgeries. All of them underwent trigeminal nerve combing. The following outcome measures were assessed: pain relief, recurrence, complication and time to pain relief.

Results

The median duration of follow-up was 52 months (range 48–96 months) in group A and 56 months (range 48–96 months) in group B. Excellent relief and good relief were noted in 23 patients (82.1 %) and two patients (7.1 %) from group A, respectively, and in 20 (62.5 %) and eight patients (25 %) from group B. The major complication of both groups was facial numbness. And the total complication rate was 15.8 % in group A and 18.8 % in group B. Recurrence was found in one patient in group A and in two in group B by the end of follow-up.

Conclusion

Trigeminal nerve combing is effective in treating TN, but has a much higher pain relief rate in patients without vascular compression than those with vascular compression.     

Discovery of a new waveform for intraoperative monitoring of hemifacial spasms

Background

Surgeons often rely on intraoperative electrophysiological monitoring to determine whether decompression is sufficient during microvascular decompression surgery for hemifacial spasms. A new monitoring method is needed when an abnormal muscle response is occasionally not available or is unreliable. This study was an observational clinical trial exploring a new waveform recorded from the facial muscles while the offending artery wall was electrically stimulated.

Methods

Thirty-two patients with typical hemifacial spasm and 12 with trigeminal neuralgia as a control were included. The facial muscle response was recorded during microvascular decompression surgery while the offending artery wall was stimulated (2?mA?×?0.2?ms). The latency, amplitude, and effective refractory period were analyzed.

Results

A waveform was recorded from the facial muscles of patients with hemifacial spasm when the offending artery wall was stimulated and was named the “Z-L response.” The latency was 7.3?±?0.8?ms, the amplitude was 0.08?±?0.02?mV, and the effective refractory period was 3.5–4?ms. The Z-L response disappeared immediately after microvascular decompression. No waveform was recorded from the facial muscles of patients with trigeminal neuralgia while the anterior inferior cerebellar artery, which adheres to the facial nerve, was stimulated (2?mA?×?0.2?ms).

Conclusion

We found a new waveform for intraoperative monitoring of hemifacial spasm. The Z-L response was useful when the abnormal muscle response was absent before decompression or persisted after all vascular compressions were properly treated. Particularly, the Z-L response may help neurosurgeons determine the real culprit when multiple offending vessels exist.     

Preoperative assessment of trigeminal neuralgia and hemifacial spasm using constructive interference in steady state-three-dimensional Fourier transformation magnetic resonance imaging

Results of microvascular decompression (MVD) for trigeminal neuralgia (TN) and hemifacial spasm (HFS) may be improved by accurate preoperative assessment of neurovascular relationships at the root entry/exit zone (REZ). Constructive interference in steady state (CISS)-three-dimensional Fourier transformation (3DFT) magnetic resonance (MR) imaging was evaluated for visualizing the neurovascular relationships at the REZ. Fourteen patients with TN and eight patients with HFS underwent MR imaging using CISS-3DFT and 3D fast inflow with steady-state precession (FISP) sequences. Axial images of the cerebellopontine angle (CPA) obtained by the two sequences were reviewed to assess the neurovascular relationships at the REZ of the trigeminal and facial nerves. Eleven patients subsequently underwent MVD. Preoperative MR imaging findings were related to surgical observations and results. CISS MR imaging provided excellent contrast between the cranial nerves, small vessels, and cerebrospinal fluid (CSF) in the CPA. CISS was significantly better than FISP for delineating anatomic detail in the CPA (trigeminal and facial nerves, petrosal vein) and abnormal neurovascular relationships responsible for TN and HFS (vascular contact and deformity at the REZ). Preoperative CISS MR imaging demonstrated precisely the neurovascular relationships at the REZ and identified the offending artery in all seven patients with TN undergoing MVD. CISS MR imaging has high resolution and excellent contrast between cranial nerves, small vessels, and CSF, so can precisely and accurately delineate normal and abnormal neurovascular relationships at the REZ in the CPA, and is a valuable preoperative examination for MVD.     

A recommendation on the basis of long-term follow-up resultsof our microvascular decompression operation for hemifacial spasm

Background

Microvascular decompression (MVD) for hemifacial spasm (HFS) has been popular, but it may take enough time to master this special operative technique and procedure. This may induce uneven distribution of the number of MVD operations in each institute, possibly resulting in an overall unsatisfactory quality of MVD surgeons. Nakanishi’s approach to MVD operations has the feature of using a, “supine, no retractor” technique, which would achieve various benefits for patients and medical professionals. We would like to recommend this approach for MVD surgeons on the basis of our follow-up outcomes.

Methods

A questionnaire, which was based on the method of evaluation for the long-term results of post-MVD operation as recommended by the Japanese Society of MVD, was sent by mail to the 154 HFS patients who had received Nakanishi’s approach at our hospital.

Results

Except for 42 patients who had changed their residences, 89 patients (79.5 % of 112) fully answered. The mean postoperative follow-up term was 13.0 years. The 76.4 % of the patients was estimated as excellent. Postoperative deafness was not present. The average value of satisfaction degree for the results of the MVD operation was 87.9 %.

Conclusions

This study revealed that Nakanishi’s approach produced good results equivalent of other approaches for HFS patients. This approach is considered to have many advantages comparing to the other approaches. Therefore, we would like to recommend that Nakanishi’s approach would contribute to overall advancement of the level of MVD surgeons.     

The strategy of microvascular decompression for hemifacial spasm: how to decide the endpoint of an MVD surgery

Objective

Microvascular decompression (MVD) has become the standard treatment for hemifacial spasm. As not all patients get complete relief, this strategy is still controversial. The study aimed to figure out how to tell the proper endpoint to the surgery.

Methods

A series of 356 consecutive patients with hemifacial spasm were enrolled in this study. All patients fell into two groups according to the period they presented. Two different criteria (simple criterion vs. complex criterion) to end an operation were applied respectively. The intra-operative finding, results and complications of these two groups were compared. The advantage of the complex criterion was analyzed.

Results

The group which used complex criterion got better results than the group which used simple criterion. The complex criterion which combines full-length evidence, vascular evidence and electrophysiological evidence proved to be reliable to tell the proper endpoint to the surgery.

Conclusion

MVD operations can be ended only after the full-length evidence, vascular evidence and electrophysiological evidence are all present.     

Disease of lower cranial nerves caused by vascular compression

Between April 1989 and September 2007, 181 patients with disease of lower cranial nerves (DLCN) underwent posterior fossa exploration. As a cause of DLCN, vascular compression (VC) was present in 89 patients with trigeminal neuralgia (TN), in 6 with hemifacial spasm (HFS), in 1 with glossopharyngeal neuralgia, in 1 with Meniere's disease, and in 5 with multiple DLCN. Depending on intraoperative findings, different surgical options were used: microvascular decompression (MVD), MVD with partial sensory rhizotomy (PSR) or total sensory rhizotomy (TSR). Statistic analysis was made using the Fisher's exact 2-side test. In patients with TN, excellent outcome was archived in 83 patients and good in 6. Postoperative outcome was better (p = 0.007) in cases with severe VC, but without significant correlation between used surgical option and outcome (p = 0.402). Frequency rate of relapses did not depend on severity of VC (p = 0.502) and used surgical option (p = 0.175). In 6 patients with HFS, excellent outcome was archived in 5 with arterial compression and poor in 1 with venous contact. In patients with Meniere's disease and glossopharyngeal neuralgia, MVD result with excellent outcome. In 5 patients with multiple DLCN, excellent outcome was archived in 3 and good in 2. MVD is method of choice in surgical treatment of DLCN caused by VC. Overall outcome is better with severity of VC.