Results of reoperation for failed microvascular decompression

Repeat Surgery for Recurrent or Refractory Trigeminal Neuralgia: A Systematic Review and Meta-Analysis

OBJECTIVE

Surgery can effectively treat Trigeminal neuralgia (TN), but postoperative pain recurrence or nonresponse are common. Repeat surgery is frequently offered but limited data exist to guide the selection of salvage surgical procedures. We aimed to compare pain relief outcomes after repeat microvascular decompression (MVD), percutaneous rhizotomy (PR), or stereotactic radiosurgery (SRS) to determine which modality was most efficacious for surgically refractory TN.

METHODS

A PRISMA systematic review and meta-analysis was performed, including studies of adults with classical or idiopathic TN undergoing repeat surgery. Primary outcomes included complete (CPR) and adequate (APR) pain relief at last follow-up, analyzed in a multivariate mixed-effect meta-regression of proportions. Secondary outcomes were initial pain relief and facial numbness.

RESULTS

Of 1299 records screened, 61 studies with 68 treatment arms (29 MVD, 14 PR, and 25 SRS) comprising 2165 patients were included. Combining MVD, PR, and SRS study data, 68.8% achieved initial CPR after a repeat TN procedure. On average, 49.6% of the combined sample of MVD, PR, and SRS had CPR at final follow-up, which was on average 2.99 years postoperatively. The proportion (with 95% CI) achieving CPR at final follow-up was 0.57 (0.51-0.62) for MVD, 0.60 (0.52-0.68) for PR, and 0.35 (0.30-0.41) for SRS, with a significantly lower proportion of pain relief with SRS. Estimates of initial CPR for MVD were 0.82 (0.78-0.85), 0.68 for PR (0.6-0.76), and 0.41 for SRS (0.35-0.48).

CONCLUSIONS

Across MVD, PR, and SRS, about half of TN patients maintain complete CPR at an average follow-up time of 3 years after repeat surgery. In treating refractory or recurrent TN, MVD and PR were superior to SRS in both initial pain relief and long-term pain relief at final follow-up. These findings can inform surgical decision-making in this challenging population.

Microvascular decompression using autologous muscle graft for trigeminal neuralgia: a case series and meta-analysis

PURPOSE

We aimed to describe a case series of patients diagnosed with trigeminal neuralgia (TN) who were submitted to microvascular decompression (MVD) using autologous muscle graft (AMG) and perform a systematic review and meta-analysis.

METHODS

Forty-four adult patients who underwent MVD using AMG between 2012 and 2022 were studied retrospectively. Demographic, clinical, and surgical factors were assessed. We systematically reviewed PubMed, Embase, and Cochrane Library from inception to May 2023. We used random-effects model for all outcomes. Heterogeneity was assessed with I2. We used R software 4.3.1 for all statistical analyses.

RESULTS

Among patients in the case series, the mean age was 52 ± 12.9 years, and the proportion of females was 65.9%. Forty-one patients (93.2%) presented complete pain relief after a mean follow-up of 7.7 years. The pooled analysis of immediate pain relief was 91.3% (95% CI 82-96%; I2=78%). The good pain relief during follow-up was 88.2% (95% CI 78-94%; I2=80%) at follow-up. The recurrence rates at 6, 12, 36 months, and during follow-up were 6.2%, 10.5%, 10.3%, and 11%, respectively.

CONCLUSION

In this case series and meta-analysis of over 440 patients, our findings suggest that the practice of MVD using AMG may be an efficient option in the short term as surgical treatment for TN. Further trials should compare AMG with other materials and its effectiveness in a long-term follow-up.

Microsurgical posterior fossa re-exploration for recurrent trigeminal neuralgia after previous microvascular decompression: common grounds-scarring, deformation, and the "piston effect"

OBJECTIVE

Microvascular decompression (MVD) is a well-accepted treatment modality for trigeminal neuralgia (TN) with high initial success rates. The causes for recurrence of TN after previously successful MVD have not been fully clarified, and its treatment is still a matter of debate. Here, we present the surgical findings and the clinical outcome of patients with recurrent TN after MVD who underwent posterior fossa re-exploration.

METHODS

Microsurgical posterior fossa re-exploration was performed in 26 patients with recurrent TN (mean age 59.1 years) who underwent MVD over a period of 10 years. The trigeminal nerve was exposed, and possible factors for recurrent TN were identified. Arachnoid scars and Teflon granulomas were dissected meticulously without manipulating the trigeminal nerve. Outcome of posterior fossa re-exploration was graded according to the Barrow Neurological Institute (BNI) pain intensity score. Follow-up was analyzed postoperatively at 3, 12, and 24 months and at the latest available time point for long-term outcome.

RESULTS

The mean duration of recurrent TN after the first MVD was 20 months. Pain relief was achieved in all patients with recurrent TN on the first postoperative day. Intraoperative findings were as follows: arachnoid scar tissue in 22/26 (84.6%) patients, arterial compression in 1/26 (3.8%), venous contact in 8/26 (30.8%), Teflon granuloma in 14/26 (53.8%), compression by an electrode in Meckel's cave used for treatment of neuropathic pain in 1/26 (3.8%), evidence of pulsations transmitted to the trigeminal nerve through the Teflon inserted previously/scar tissue ("piston effect") in 15/26 (57.7%), and combination of findings in 18/26 (69.2%). At long-term follow-up (mean 79.5 months; range, 29-184 months), 21/26 (80.8%) patients had favorable outcome (BNI I-IIIa). New hypaesthesia secondary to microsurgical posterior fossa re-exploration occurred in 5/26 (19.2%) patients.

CONCLUSIONS

Posterior fossa re-exploration avoiding manipulation to the trigeminal nerve, such as pinching or combing, may be a useful treatment option for recurrent TN after previously successful MVD providing pain relief in the majority of patients with a low rate of new hypaesthesia.

Outcome after microvascular decompression for trigeminal neuralgia in a single center-relation to sex and severity of neurovascular conflict

BACKGROUND

Trigeminal neuralgia (TN), a severe type of facial pain, is mainly caused by a neurovascular conflict (NVC). The severity of the NVC seems associated with the outcome following microvascular decompression (MVD) surgery. This study aimed to investigate the outcome after MVD and whether it is affected by NVC severity and sex.

METHODS

TN patients (n = 109) were followed for 5 to 10 years after MVD. Barrow Neurology Index (BNI), Patients Global Impression of Change (PGIC), complications, and time to relapse were evaluated. The NVC severity was retrospectively reviewed from presurgical MRI. Demographic and clinical factors and NVC severity were analyzed for potential association with outcome after MVD.

RESULTS

The success rate (BNI ≤ 2) was 80% after 5 to 10 years follow-up for TN patients with severe NVC (grade 2-3) and 56% for TN patients with mild NVC (grade 0-1, P = 0.003). No sex difference was observed in outcome for patients with both mild (P = 0.924) and severe NVC (P = 0.883) respectively. Three patients (2.8%) during the hospital stay, and two patients (1.8%) at 6 weeks, experienced a complication requiring invasive treatment. At long-term 52/109 patients (47.7%) reported some type of persistent adverse event, of which the majority were mild and required no treatment.

CONCLUSIONS

MVD offers an 80% probability of long-term pain relief in TN patients with severe NVC, with low frequency of serious complications. NVC severity significantly affects outcome after MVD, while no sex differences in outcome were found. In consistency with previous work, the results stress the importance of adequate neuroradiological assessment of the NVC for preoperative patient selection.

Sling technique in microvascular decompression surgery for trigeminal neuralgia: early experience and functional outcomes

Background

Trigeminal neuralgia (TGN) is a facial pain disorder often caused by arterial compression of the trigeminal nerve. Microvascular decompression (MVD) remains the most definitive treatment for this disorder, with a reported cure rate between 60 and 80%. MVD techniques often involve a retrosigmoid craniotomy with placement of an inert foreign material, such as Gore-Tex or Teflon, between the nerve and the compressing vessel.

Recurrence of TGN after MVD has been associated with vessel migration and adhesion formation. In this study, we tested the use of Gore-Tex sling, fixed in place with fibrin glue to displace the compressing vessel away from the nerve.

Results

This is a retrospective study including 20 patients who had an MVD for treatment of idiopathic TGN where a sling of Gore-Tex was used with the application of fibrin glue to prevent dislocation of the vessel. It showed that sling MVD technique is an effective method for treatment of classic trigeminal neuralgia. Eighteen patients improved within 2 weeks postoperatively. One patient had recurrence of symptoms and was reoperated 1 year later.

Conclusion

Gore-Tex slinging technique is a safe simple technique for preventing re-dislocation of the offending vessel and thus recurrence of symptoms. However, larger series is needed to judge on the long-term efficacy and safety of this technique.

A Systematic Review of Repeat Microvascular Decompression for Recurrent or Persistent Trigeminal Neuralgia

OBJECTIVE

When conservative therapy fails, microvascular decompression (MVD) has been the preferred treatment of primary trigeminal neuralgia (TN). However, the management of recurrent or persistent TN after MVD can often be difficult. The purpose of the present systematic review was to objectively analyze and summarize the reported literature regarding the feasibility of repeat MVD.

METHODS

We conducted a database search using the MEDLINE and PubMed databases until July 2020. The search terms used for title and abstract screening were as follows: "recurrent trigeminal neuralgia," "persistent trigeminal neuralgia," "repeat microvascular decompression," and "reexploration." The inclusion criteria for the systematic review were as follows: clinical studies (excluding case studies), repeat MVD treatment of TN, and studies that had recorded the pain relief outcomes, operative findings, and complications (if any).

RESULTS

Of the 1771 initial results obtained, we performed a full text screening of 43 studies, and, ultimately, 19 were deemed eligible. A total of 2247 patients had undergone MVD for TN, of whom, 311 had experienced recurrence (13.84%). Of the 311 patients, 178 had undergone repeat MVD. The average pain-free interval was 27.75 months after the first MVD. The effective rate of repeat MVD was 91.66%, and 71.48% of the patients had had obvious compression found at repeat MVD. The postoperative complication rate after repeat MVD was 37.31% and was due to postoperative adhesions around the nerve and nerve injury caused by partial sensory rhizotomy. The most common complication after repeat MVD was facial numbness (21.89%), although the incidence of other complications was <5%.

CONCLUSIONS

For patients with recurrent or persistent pain after MVD, the findings from our systematic review support that repeat MVD remains a feasible treatment for recurrent or persistent TN.

Spasm Freedom Following Microvascular Decompression for Hemifacial Spasm: Systematic Review and Meta-Analysis

BACKGROUND

Hemifacial spasm (HFS) is a debilitating disorder characterized by intermittent involuntary movement of muscles innervated by the facial nerve. HFS is caused by neurovascular compression along the facial nerve root exit zone and can be treated by microvascular decompression (MVD). The goal was to determine rates and predictors of spasm freedom after MVD for HFS.

METHODS

A literature search using the key terms "microvascular decompression" and "hemifacial spasm" was performed. The primary outcome variable was spasm freedom at last follow-up. Analysis was completed to evaluate for variables associated with spasm-free outcome.

RESULTS

A total of 39 studies including 6249 patients were analyzed. Overall spasm freedom rate was 90.5% (5652/6249) at a follow-up of 1.25 ± 0.04 years. There was no significant relationship between spasm freedom versus persistent spasm and age at surgery, timing of follow-up, gender, disease duration, side of disease, or vessel type. Spasm freedom was more likely after an initial surgery versus a redo MVD (odds ratio 4.16, 95% confidence interval 1.99-8.68; P < 0.01).

CONCLUSIONS

MVD works well for HFS with cure rates >90% at 1-year follow-up in 6249 patients from 39 studies. A significant predictor of long-term spasm freedom at 1 year was an initial MVD as compared to repeat MVD. The majority of published manuscripts on MVD for HFS are heterogeneous single-institutional retrospective studies. As such, a large-scale meta-analysis reporting outcome rates and evaluating significant predictors of spasm freedom provides utility in the absence of randomized controlled studies.

Surgical Outcomes of Revision Microvascular Decompression for Persistent or Recurrent Hemifacial Spasm After Surgery: Analysis of Radiologic and Intraoperative Findings

OBJECTIVES

Microvascular decompression (MVD) is the treatment of choice for hemifacial spasm (HFS), due to the high rate of complete resolution associated with MVD. However, some patients experience recurrent or persistent symptoms after surgery. In this study, we evaluated the causes of recurrence or failure based on our surgical experience with revision of MVD for HFS and analyzed the relationship between surgical outcomes and radiologic and intraoperative findings.

METHODS

Among more than 2500 patients who underwent MVD surgery for HFS, 23 patients received a second MVD in our hospital from January 2002 to December 2017. Three-dimensional time-of-flight magnetic resonance angiography and reconstructed imaging were used to identify the culprit vessel and its conflict on the root exit zone (REZ) of the facial nerve. We reviewed patients' medical records and operation videos to identify the missing points of first surgery.

RESULTS

In our experience with revision of MVD, 8 patients had incomplete decompression, such as single-vessel decompression of multiple offending vessels. Teflon was not detected at the REZ but was found in other locations in 12 patients. Three patients had severe adhesion with previous Teflon around the REZ. Nineteen patients had excellent surgical outcomes at immediate postoperative evaluation; 20 patients showed spasm disappearance at 1 year after surgery and 3 patients showed persistent symptoms. Neurovascular contacts around the REZ of the facial nerve were revealed on magnetic resonance imaging of incomplete decompression and Teflon malposition patient groups. There were no clear neurovascular contacts in the patients with severe Teflon adhesion.

CONCLUSIONS

The decision regarding secondary MVD for persistent or recurrent spasm is troubling. However, if neurovascular contact was observed in the MRI of the patient and there were offending vessels, the surgical outcome might be favorable.

Application of MRI and intraoperative CT fusion images with integrated neuronavigation in percutaneous radiofrequency trigeminal rhizotomy

BACKGROUND

Percutaneous radiofrequency trigeminal rhizotomy (RF-TR) has been an effective treatment modality for medically refractory trigeminal neuralgia. Our group has established a protocol for this procedure that includes intraoperative computed tomography (iCT) navigation. The depth of the puncture needle in our protocol was based on cadaveric studies, and anatomical localization was mainly by electric stimulation test. The limitation of the invisibility of the trigeminal cistern on CT imaging and bias from the patient's subjective expression during neurophysiologic stimulation might affect the accuracy of the needle tip and the treatment effect.This study aimed to evaluate the feasibility and preliminary results of the application of magnetic resonance imaging (MRI) and iCT fusion imaging in RF-TR.

METHOD

The study included 13 patients who received RF-TR with iCT navigation and with recurrence within 3 years. Repeated RF-TR was performed with real-time guidance by MRI and iCT fusion imaging.

RESULTS

A pain-free or partial satisfactory response was reported with 12 patients (92 %). There was a statistically significant difference in the depth of the needle tip before and after application of MRI and iCT fusion imaging.

CONCLUSIONS

This preliminary study demonstrated that the application of MRI and iCT fusion could help with anatomical localization of the trigeminal cistern intraoperatively. The improvement in neuronavigation provides a choice in the treatment of recurrent or persistent trigeminal neuralgia after previous intervention. Long-term follow-up of the result is necessary to evaluate the benefit in terms of durability of therapeutic efficacy.

Intractable hemifacial spasm treated by pulsed radiofrequency treatment

Hemifacial spasm is defined as unilateral, involuntary, irregular twitching of all or parts of the muscles innervated by facial nerves. Here, we present a case of recurrent hemifacial spasm after microvascular decompression (MVD) treated with pulsed radiofrequency (PRF) treatment with good results. A 35-year-old woman suffered from recurrent hemifacial spasm after MVD that was refractory to medical treatment and botulinum toxin injections. We attempted a left facial nerve block twice. Then, we applied PRF at a maximum temperature of 42℃ for 120 sec. Some response was observed, so we applied PRF two additional times. The frequency of twitch decreased from 3-4 Hz to < 0.5 Hz, and subjective severity on a visual analogue scale also decreased from 10/10 to 2-3/10. PRF treatment might be an effective medical treatment for refractory hemifacial spasm and has fewer complications and is less invasive compared with those of surgery.

Outcomes of surgical treatment for hemifacial spasm associated with the vertebral artery: severity of compression, indentation, and color change

OBJECT

The object of surgical treatment for hemifacial spasm (HFS) is the exclusion of pulsatile neurovascular compression of the root exit zone (REZ). However, spasm persists transiently or permanently in some cases even after complete decompression. In particular, we mainly experience these results when the vertebral artery (VA) is the offender. Hence, we verified color changes of the nerve and indentations from within the operative field in HFS patients with the VA as the offender. So, we reviewed retrospectively the records of those patients who were treated with microvascular decompression (MVD) in order to assess the relationship between operative findings and clinical results.

METHODS

A total of 232 patients with HFS associated with the VA were treated with MVD between January 1994 and January 2009 at our institution. The patients were classified into one of the following three categories based on compression severity: Group I, mild; Group II, moderate; Group III, severe. The patients were also classified into one of the following four categories based on the existence of indentation and discoloration of nerve VII: Group A (-/-), B (+/-), C (-/+), or D (+/+).

RESULTS

A total of 94.2% and 96.6% of the patients in Groups I and II, respectively, had improved to grades I-II at the last follow-up. The surgical outcomes of Group III were slightly poorer than those of Groups I and II. Group A showed the poorest outcomes with 60% of the patients classified as grades III-IV. In Group B, 98.4% of the patients showed a marked improvement and Groups C and D showed relatively poor outcomes compared with those of Group B.

CONCLUSIONS

Severe deviations and color changes of the facial nerves may be the risk factors for poor surgical outcomes. Future studies with larger sample sizes and investigations of the pathophysiology underlying these findings are needed.

Unusual recurrence of trigeminal neuralgia after microvascular decompression by muscle interposal

BACKGROUND

Patients with trigeminal neuralgia (TN) and persistent or recurrent facial pain after microvascular decompression (MVD) typically undergo less invasive procedures in the hope of providing pain relief. However, re-operation should be considered in selected patients.

CASE REPORT

A 48-year-old woman presented with recurrent trigeminal neuralgia (TN) 3 years following microvascular decompression (MVD). The patient underwent brain magnetic resonance angiography (MRA), which did not reveal neurovascular compression; therefore surgical re-exploration was carried out. During the operation, the fifth cranial nerve was seen without impingement from any blood vessels; however, a very firm tissue was observed and identified as the muscle fragment from the previous MVD procedure. The fifth cranial nerve was carefully separated from the muscle. Thereafter, the right SCA was dissected out from the muscle and suspended by a periosteum tape sutured to the nearby dura.

CONCLUSIONS

Our findings, along with similar cases reported in the literature, support the development of new inert materials and alternative surgical strategies that can limit TN recurrence.

Vertebral artery pexy for microvascular decompression of the facial nerve in the treatment of hemifacial spasm

Object

Hemifacial spasm (HFS) is caused by arterial or venous compression of cranial nerve VII at its root exit zone. Traditionally, microvascular decompression of the facial nerve has been an effective treatment for posterior inferior and anterior inferior cerebellar artery as well as venous compression. The traditional technique involves Teflon felt or another construct to cushion the offending vessel from the facial nerve, or cautery and division of the offending vein. However, using this technique for severe vertebral artery (VA) compression can be ineffective and fraught with complications. The authors report the use of a new technique of VA pexy to the petrous or clival dura mater in patients with HFS attributed to a severely ectatic and tortuous VA, and detail the results in a series of patients.

Methods

Six patients with HFS due to VA compression underwent a retrosigmoid craniotomy, combined with a far-lateral approach in some patients. On identification of the site of VA compression, the vessel was mobilized adequately for the decompression. Great care was taken to avoid kinking the perforating vessels arising from the VA. Two 8-0 nylon sutures were passed through to the wall of the VA and then through the clival or petrous dura, and then tied to alleviate compression on cranial nerve VII.

Results

Patients were followed for at least 1 year postoperatively (mean 2.7 years, range 1–4 years). All 6 patients had complete resolution of their HFS. Facial function was tested postoperatively, and was stable when compared with the preoperative baseline. Two of the 3 patients with preoperative tinnitus had resolution of this symptom after the procedure. Postoperative imaging demonstrated VA decompression of the facial nerve and no evidence of stroke in all patients. One patient suffered from hearing loss, another developed a postoperative transient unilateral vocal cord paralysis, and a third patient developed a pseudomeningocele that resolved with the placement of a lumbar drain.

Conclusions

Hemifacial spasm and other neurovascular syndromes are effectively treated by repositioning the compressing artery. Careful study of the preoperative MR images may identify a select group of patients with HFS due to an ectatic VA. Rather than traditional decompression with only pledget placement, these patients may benefit from a VA pexy to provide an effective, safe, and durable resolution of their symptoms while minimizing surgical complications.

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.

Surgical treatment of cranial neuralgias

The most common types of cranial neuralgias amenable to surgical therapeutic options are trigeminal neuralgia and glossopharyngeal neuralgia, the former having an approximate incidence of 5/100000 cases per year and the latter of 0.05/100000 cases per year. Surgical therapy of these pathological conditions encompasses several strategies, going from ablative procedures to neurovascular decompression, to radiosurgery. The choice of the most appropriate surgical option (which must be taken into account when all conservative treatments have proven to be unsuccessful) has to take into account many factors, the most important ones being neuroradiological evidence of a neurovascular conflict, severity of symptoms, the age and clinical history of the patient, and the patient's overall medical condition. In this chapter we report our experience with the treatment of trigeminal and glossopharyngeal neuralgia, describing the surgical procedures performed and reviewing the most recent aspects on this subject in the past literature.

Microvascular decompression for trigeminal neuralgia: the importance of a noncompressive technique--Kaplan-Meier analysis in a consecutive series of 330 patients

OBJECTIVE

Microvascular decompression, although a well-established procedure for treating primary trigeminal neuralgia, still has no standardized protocol. The practical consequences of having the implant keep the conflicting vessels apart, whether or not in contact with the root, is still in debate. The present work was undertaken to answer this question.

METHODS

Patients were segregated into 2 groups: Group I (260 patients) had a Teflon prosthesis implanted without contact to the root, and Group II (70 patients) had a similar implant with contact to the root. Cure rates in the 2 groups were compared at the latest follow-up (</=15 yr; average, 8.2 yr) using Kaplan-Meier analysis.

RESULTS

In Group I, the cure rate was 82% (214 of 260 patients), whereas in Group II, the cure rate was 67% (47 of 70 patients) (P = 0.01). Kaplan-Meier analysis of the follow-up period up to 15 years also shows a significant difference (P = 0.05).

CONCLUSION

These results strongly support the goal of performing the procedure without the implant in contact with the root. This is easier with the superior cerebellar artery, because of its laxity and small number of perforating branches, than with the anteroinferior cerebellar artery, which has perforators to the brainstem and labyrinthine artery arising from its cisternal portion. The significantly better long-term cure rate when the implant is not in contact with the root favors the "pure" decompressive effect of the microvascular decompression procedure, rather than a conduction block mechanism.

Microvascular decompression for primary trigeminal neuralgia: long-term effectiveness and prognostic factors in a series of 362 consecutive patients with clear-cut neurovascular conflicts who underwent pure decompression

Object

The purpose of this study was to evaluate the long-term efficacy of microvascular decompression (MVD) and to identify the factors affecting outcome in patients treated for primary trigeminal neuralgia (TN). Only the cases with a clear-cut neurovascular conflict (vascular contact and/or compression of the root entry zone of the trigeminal nerve) found at surgery and treated with “pure” MVD (decompression of the root without any additional lesioning or cutting of the adjacent rootlets) were retained.

Methods

The study included 362 patients who were followed up over a period of 1 to 18 years (median follow-up 7.2 years). A Kaplan–Meier survival analysis was generated at 1 and 15 years of follow-up for all of the considered factors. According to Kaplan–Meier analysis, the success rate (defined as pain-free patients without any medication) was 91% at 1 year and estimated to be 73.38% after 15 years of follow-up.

Results

None of the following patient-related factors played any significant role in prognosis: sex, patient age at surgery, history of systemic hypertension, duration of neuralgia before surgery, or history of failed trigeminal surgery. Patients with atypical neuralgia (a baseline of permanent pain) had the same outcome as those with a typical (purely spasmodic) presentation. In addition, the side and topography of the trigeminal nerve did not play a role, whereas involvement of all three divisions of the nerve had a negative effect on outcome. Concerning anatomical factors, neither the type of the compressive vessel nor its location along or around the root was found to be significant. However, the severity of compression was important—the more severe the degree of compression, the better the outcome (p = 0.002). The authors also found that presence of focal arachnoiditis had a negative influence on outcome (p = 0.002).

Conclusions

Pure MVD can offer patients affected by a primary TN a 73.38% probability of long-term (15 years) cure of neuralgia. The presence of a clear-cut and marked vascular compression at surgery (and possibly—although not yet reliably—on preoperative magnetic resonance imaging) is the guarantee of a higher than 90% success rate.

Recurrent trigeminal neuralgia secondary to Teflon felt

The authors present a case of a 45-year-old man with recurrent trigeminal neuralgia twelve years after microvascular decompression. The patient underwent surgical reexploration of the trigeminal nerve. A piece of hardened Teflon felt was found piercing a hole through the trigeminal nerve. No other compression of the nerve was found. Removal of the Teflon felt resolved the neuralgia. To the authors knowledge this is the first report of recurrent trigeminal neuralgia due to such a mechanism. This case emphasises the need for further improvement of the surgical technique for microvascular decompression of the trigeminal neuralgia.

Microvascular Decompression in Trigeminal Neuralgia with No Vascular Compression

BACKGROUND

Microvascular decompression (MVD) is a well-known surgical procedure with one of the best long-term results in the therapy of trigeminal neuralgia. But the exact pathophysiology of this disease has not yet been elucidated. Cases with undetectable vascular compression who are cured after MVD make this dilemma clear. Autopsy studies have also shown vascular compression in asymptomatic cases.

METHODS

Five of 40 cases with TN treated with MVD in our clinic had no visible vascular compression. Diagnosis was made with MRI and MRA.

RESULTS

Surprisingly all of these 5 patients were cured with MVD. Two of them needed only one operation to become pain free and 3 a second operation.

CONCLUSION

We think that the therapeutic effect of MVD is due to minimal trauma of the nerve. It seems that MVD is a good alternative strategy with low complication rates in comparison to ablative procedures.

Micro-vascular decompression for primary Trigeminal Neuralgia (typical or atypical). Long-term effectiveness on pain; prospective study with survival analysis in a consecutive series of 362 patients

BACKGROUND

Few publications on primary Trigeminal Neuralgia treated by Micro-Vascular Decompression (MVD) report large series, with long-term follow-up, using Kaplan-Meier (K-M) analysis. None was specifically directed to the comparative study of MVD effectiveness on Trigeminal Neuralgia with typical (i.e., with paroxysmal pain only) and atypical features (i.e., with association of a permanent background of pain).

METHOD

The authors report a series of 362 patients having clearcut vascular compression and treated with pure MVD - i.e., without any additional cut or coagulation of the adjacent root fibers. Follow-up was 1 to 18 y (8 y on average, with a median of 7.2 y). Results were considered overall, then separately for patients with typical (237 (65.5%)) and atypical (125 (34.5%)) clinical presentation.

FINDINGS

One year after operation, (294 (81.2%) of patients were totally-free - of paroxysmal pain, and also of permanent background pain - and not needing any medication) 13 (3.6%) still had a background of pain but without the need for medication which 55 patients (15.2%), treatment had failed. At latest review (8 y on average) the corresponding rates were 80, 4.9 and 15.1%, respectively. Kaplan-Meier analysis estimated the probability of total cure at 15 y to be 73.4%. There was no difference in the cure rate between patients with typical and atypical features at one year: 81 and 81.16%, respectively. The probability of cure at 15 y was identical for the two clinical presentations.

CONCLUSIONS

Pure MVD offers patients affected by Trigeminal Neuralgia due to vascular compression a long-lasting cure in three-fourths of the cases. Both typical and atypical presentations respond well to MVD, view in contrast to the classical view that an atypical presentation has an adverse effect on outcome after surgery.

Reoperation for Persistent or Recurrent Hemifacial Spasm after Microvascular Decompression

OBJECTIVE:

The objective of this study was to investigate the outcome of reoperation for persistent or recurrent hemifacial spasm (HFS) after microvascular decompression (MVD).

METHODS:

Repeat MVD was performed on 13 patients with an HFS between June 1994 and May 2004. Patients who had compressing offending vessels identified on postoperative (prerevision) three-dimensional short-range magnetic resonance angiography were selected for repeat MVD.

RESULTS:

Six patients were found to have no improvement in HFS with the first MVD. All of these patients exhibited excellent improvement after the second MVD. In one patient who had mild improvement with the first MVD, but with more than 50% of remaining spasm, complete abolition of spasm occurred immediately after the second MVD. Six patients showed initial relief and subsequent aggravation of HFS after the first MVD. Of these patients, four had excellent results with the second MVD, one had a good result, and one had a fair outcome. Adverse effects after the second MVD were found in two patients (one patient with permanent mild facial weakness and one patient with hearing impairment). There was no serious morbidity associated with the second MVD.

CONCLUSION:

Our data suggest that repeat MVD of the facial nerve may be sufficient to resolve symptoms in selected patients with persistent or recurrent HFS. Additionally, three-dimensional short-range magnetic resonance angiography may help to identify the offending vessels and to select the patients with persistent or recurrent HFS.

Microvascular Decompression for Trigeminal Neuralgia in the Elderly: A Review of the Safety and Efficacy

OBJECTIVE:

To critically examine the efficacy and safety of microvascular decompression (MVD) for trigeminal neuralgia (TN) in elderly patients.

METHODS:

We performed a retrospective review of medical records, followed by prospective follow-up. The outcome data from 44 MVD operations for TN performed in 40 consecutive patients with a mean age of 65 years (range, 60–75 yr) in the period 1991 to 2001 were compared with those from 40 younger control subjects (mean age, 46 yr; range, 20–59 yr) operated on during the same period.

RESULTS:

The median time from diagnosis of TN to MVD in the older patients was 7 years (range, 1–22 yr), compared with 3 years (range, 3 mo to 20 yr) in the younger group (P = 0.02). With the exception of one, all patients in this study were classified as American Society of Anesthesiologist Grade 1 or 2. Initial pain relief was achieved in 98 and 100% of the patients in the study and control groups, respectively. There were no operative mortalities or life-threatening morbidities. Transient facial numbness and diplopia occurred in both groups. Headaches, nausea, and vomiting were more frequent in the younger patients, whereas wound infection and confusion were more common in the older patients. The mean length of hospital stay was 5.4 days (range, 3–10 d) for the older patients, compared with 5.3 days (range, 3–9 d) for the control group (P = 0.4). After average follow-ups of 30 and 33 months, the pain recurred in 24 and 27% of the patients in the elderly and control groups, respectively.

CONCLUSION:

MVD is underused in the elderly despite being both safe and effective. Fitness and not age should be the key in deciding the treatment options. It is proposed that any patient with medically refractory TN who is fit for general anesthesia should be given the opportunity to choose MVD.

Demonstration of neurovascular compression in trigeminal neuralgia and hemifacial spasm with magnetic resonance imaging: comparison with surgical findings in 60 consecutive cases

BACKGROUND

Until recently, it has been impossible to demonstrate vascular compression at the root entry or exit zone (REZ) of the trigeminal nerve and facial nerve in patients with trigeminal neuralgia (TN) and hemifacial spasm (HFS) preoperatively, although surgical findings have revealed apparent neurovascular compression and its correction has resulted in a good outcome in most cases. Revealing the anatomic correlation between nerves and vessels at the REZ preoperatively would be useful to predict operative findings.

METHODS

To assess whether the vascular contact of the nerve at the REZ could be demonstrated preoperatively, high-resolution magnetic resonance tomographic angiography (MRTA) was performed in 21 patients with TN and 39 with HFS. Neuroradiological findings were compared with the operative findings in all patients. Contralateral asymptomatic nerves were evaluated as a control.

RESULTS

MRTA correctly identified offending vessels in 14 (67%) of the 21 TN and 34 (87%) of the 39 HFS patients. Failure to identify neurovascular contact was noted in the cases with compression by veins or small arteries, thickened arachnoid, or distal compression. Neurovascular contact was also observed in 15% of the asymptomatic nerves. The deformity of the nerve seemed to be a more important factor for determining operative indication.

CONCLUSIONS

MRTA could demonstrate offending vessels in TN and HFS at a high rate and was useful to predict operative findings. MRTA gave supportive evidence of surgical indications in patients with TN and HFS, although attention should be paid to the fact that MRTA did not necessarily detect all of the offending vessels.

Role of postoperative magnetic resonance imaging after microvascular decompression of the facial nerve for the treatment of hemifacial spasm

OBJECTIVE

This study was performed to investigate the role of postoperative three-dimensional short-range magnetic resonance angiography in the prediction of clinical outcomes after microvascular decompression (MVD) for the treatment of hemifacial spasm.

METHODS

We examined pre- and postoperative magnetic resonance imaging scans obtained between March 1999 and May 2000 for 122 patients with hemifacial spasm, to evaluate the degree of detachment of the vascular contact and changes in the positions of offending vessels. The degree of vascular decompression of the facial nerve root was classified into three groups, i.e., contact, partial decompression, or complete decompression. Contact was defined as unresolved compression, as indicated by postoperative three-dimensional short-range magnetic resonance angiography. Partial decompression was defined as incompletely resolved compression; vascular indentation of the facial nerve was improved, but contact with the facial nerve remained. Complete decompression was defined as completely resolved compression. These findings were compared with the surgical findings and clinical outcomes.

RESULTS

Of 122 patients with MVD, complete decompression of offending vessels at the root entry zone of the facial nerve was observed for 106 patients (86.9%), partial decompression was observed for 10 patients (8.2%), and contact with offending vessels was observed for 6 patients (4.9%) by using postoperative three-dimensional short-range magnetic resonance angiography. Our study demonstrated that the types of offending vessels affected neither the degree of decompression of the root entry zone of the facial nerve nor surgical outcomes (P > 0.05). Also, there was no significant relationship between the degree of decompression and improvement of symptoms (P > 0.05). Furthermore, there was no significant relationship between the degree of decompression and the timing of symptomatic improvement (P > 0.05).

CONCLUSION

Our data suggest that MVD of the facial nerve alone may not be sufficient to resolve symptoms for all patients with hemifacial spasm. Therefore, unknown factors in addition to vascular compression may cause symptoms in certain cases, and it may be necessary to remove those factors, simultaneously with MVD, to obtain symptom resolution.

Endoscopically assisted minimally invasive microvascular decompression of hemifacial spasm

OBJECTIVE

The aim of this study was to assess the use of endoscopy in minimally invasive surgery of the cerebellopontine angle in cases of hemifacial spasm.

MATERIALS AND METHODS

Eighty patients with hemifacial spasm underwent endoscopically assisted microvascular decompression between October 1992 and October 1998, at the Ear, Nose, and Throat Department of Nord Hospital in Marseille, France. The microvascular decompression was performed via a minimally invasive retrosigmoid approach. The cerebellopontine angle was then explored by a 30-degree endoscope to visualize the root exit zone of the facial nerve and the precise location of the site of the conflict. Microvascular decompression was performed under the microscope. If the site was an artery, a Teflon sponge was inserted; if the site was a vein, it was coagulated and then dissected away from the facial nerve.

RESULTS

In 80 patients seen regularly for at least 1 year of follow-up, and including patients operated on once or twice, the procedure was successful in 92.5% of patients, brought about improvement in 3.75% (96.25% success plus improvement), and failed in 3.75%. In relation to the type of conflict, success or improvement was experienced by 90.7% of patients with simple conflicts, 86.2% of patients with multiple conflicts, and 87.5% of patients with nutcracker conflicts. No major postoperative complication or mortality occurred in this series. No facial paresis or paralysis occurred immediately postoperatively. Three patients (3.25%) experienced delayed facial palsy. Postoperative cerebrospinal fluid leak occurred in 2 patients (2.5%) and was treated surgically.

CONCLUSION

The principle of minimally invasive surgery in the cerebellopontine angle is gaining universal acceptance. The use of endoscopy in microvascular decompression for hemifacial spasm has helped tremendously in improving the results. In this study, the use of the endoscope enabled the authors to identify the site of the conflict in all cases, and to confirm the position of the Teflon sponge before closure.

Fully endoscopic vascular decompression of the glossopharyngeal nerve

Microvascular decompression of the glossopharyngeal nerve is an effective treatment of patients with glossopharyngeal neuralgia in whom compression of the nerve by a blood vessel is implicated in the pathogenesis of the disease. The standard surgical technique uses a binocular operating microscope for intra-operative visualization. Growing experience with posterior fossa endoscopy, however, has suggested that endoscopes may provide more comprehensive anatomical views of cerebellopontine angle. This report describes the case of a patient suffering from glossopharyngeal neuralgia who underwent fully endoscopic vascular decompression of the glossopharyngeal nerve. During this procedure the endoscope was used to survey the posterior fossa, guide the placement of insulating sponges, and conduct a final assessment of the intervention. We found the endoscope ideally suited to the constricted operating space of the posterior fossa, allowing for accurate localization and careful separation of the pathological vascular conflict with minimal brain retraction and no damage to surrounding structures. The versatility of endoscopy allows for superior visual appreciation of neurovascular conflicts in the posterior fossa. To date, endoscopy has primarily been used to supplement microscopy in cranial nerve decompression surgery. This report demonstrates how the endoscope can be used as the sole imaging modality in glossopharyngeal nerve decompression, with excellent results.

Recurrent trigeminal neuralgia attributable to veins after microvascular decompression

OBJECTIVE

To demonstrate the cause of and optimal treatment for recurrent trigeminal neuralgia (TN) in cases where veins were observed to be the offending vessels during the initial microvascular decompression (MVD) procedure.

METHODS

An electronic search of patient records from 1988 to 1998 revealed that 393 patients were treated with MVD for TN caused by veins. The pain recurred in 122 patients (31.0%). Thirty-two (26.2%) of these patients underwent reoperations. Clinical presentations, recurrence intervals, surgical findings, and clinical outcomes were analyzed.

RESULTS

Analysis of 32 consecutive cases of recurrent TN initially attributable to veins revealed a female predominance (female/male = 26:5), with one female patient exhibiting bilateral TN caused by venous compression. Patient ages ranged from 15 to 80 years, with a prevalence in the seventh decade. The V2 distribution of the face was involved more frequently than other divisions. For 24 patients (75%), recurrence occurred within 1 year after the initial operation. At the time of the second MVD procedure, development of new veins around the nerve root was observed in 28 cases (87.5%). After successful subsequent MVD procedures, the pain was improved in 81.3% of the cases.

CONCLUSION

The recurrence rate for TN attributable to veins is high. If pain recurs, it is likely to recur within 1 year after the initial operation. The most common cause of recurrence is the development and regrowth of new veins. Even fine new veins may cause pain recurrence; these veins may be located beneath the felt near the root entry zone or distally, near Meckel's cave. Because of the variable locations of vein recurrence, every effort must be made to identify recollateralized veins. Given the high rate of pain relief after a second operation, MVD remains the optimal treatment for the recurrence of TN attributable to vein regrowth.

Microvascular decompression for trigeminal neuralgia: comments on a series of 250 cases, including 10 patients with multiple sclerosis

OBJECTIVE

To examine surgical findings and results of microvascular decompression (MVD) for trigeminal neuralgia (TN), including patients with multiple sclerosis, to bring new insight about the role of microvascular compression in the pathogenesis of the disorder and the role of MVD in its treatment.

METHODS

Between 1990 and 1998, 250 patients affected by trigeminal neuralgia underwent MVD in the Department of Neurosurgery of the "Istituto Nazionale Neurologico C Besta" in Milan. Limiting the review to the period 1991-6, to exclude the "learning period" (the first 50 cases) and patients with less than 1 year follow up, surgical findings and results were critically analysed in 148 consecutive cases, including 10 patients with multiple sclerosis.

RESULTS

Vascular compression of the trigeminal nerve was found in all cases. The recurrence rate was 15.3% (follow up 1-7 years, mean 38 months). In five of 10 patients with multiple sclerosis an excellent result was achieved (follow up 12-39 months, mean 24 months). Patients with TN for more than 84 months did significantly worse than those with a shorter history (p<0.05). There was no mortality and most complications occurred in the learning period. Surgical complications were not related to age of the patients.

CONCLUSIONS

Aetiopathogenesis of trigeminal neuralgia remains a mystery. These findings suggest a common neuromodulatory role of microvascular compression in both patients with or without multiple sclerosis rather than a direct causal role. MVD was found to be a safe and effective procedure to relieve typical TN in patients of all ages. It should be proposed as first choice surgery to all patients affected by TN, even in selected cases with multiple sclerosis, to give them the opportunity of pain relief without sensory deficits.

Posterior fossa reexploration for persistent or recurrent trigeminal neuralgia or hemifacial spasm: surgical findings and therapeutic implications

OBJECTIVE

To evaluate the surgical findings and subsequent therapeutic implications of posterior fossa reexploration for persistent or recurrent trigeminal neuralgia (TN) or hemifacial spasm (HFS) after failed microvascular decompression (MVD).

METHODS

Between December 1975 and October 1996, the senior author performed 31 reexplorations for failure or recurrence after MVD: 23 for TN and 8 for HFS. Records were analyzed retrospectively for evidence of vascular compression in primary and secondary operations, other pertinent intraoperative findings, intraoperative therapeutic interventions, and postoperative results and complications.

RESULTS

The previously placed polyvinyl alcohol foam (Ivalon sponge; Unipoint Industries, High Point, NC) or Teflon implant (Teflon felt; CR Bard, Inc., Bard Implants Division, Billerica, MA) was found to be in good position in 100% of the patients (31 of 31 patients). New vascular compression from an arterial source was found in three patients during posterior fossa reexploration: one with TN and two with HFS. New vascular compression from a venous source was observed in one patient with HFS. A scarred Ivalon sponge or Teflon implant with apparent mass effect on the nerve root was identified in seven reexplorations. One bony source of compression was seen. No new compressive elements or other sources of root irritation were appreciated in 61% of reexplorations. Partial sensory trigeminal rhizotomy was performed in 83% of reexplorations for persistent or recurrent TN. Of eight patients undergoing reexploration for persistent or recurrent HFS, six sustained complications.

CONCLUSION

Recurrent vascular compression was seldom identified during posterior fossa reexploration for failed MVD in patients with persistent or recurrent TN or HFS. The previously placed Ivalon sponge or Teflon implant was consistently found to be in good position. Partial sensory trigeminal rhizotomy is an often effective alternative in cases of recurrent TN when neurovascular compression is not identified. However, because of the relatively high incidence of complications associated with reexploration, we recommend other ablative or medical treatments for most patients after failed MVD for TN or HFS.

Neurovascular relationships in the posterior cranial fossa, with special reference to trigeminal neuralgia. 1. Review of the literature and development of a new method of vascular injection-filling in cadaveric controls

Vascular compression of cranial nerves adjacent to the brain stem has been implicated in a wide variety of disorders affecting their function. The considerable conflicts in published results relate primarily to flaws in study design. The design required of an adequate study is defined and a technique is presented, in 16 fresh human cadavers, of reliable and physiological injection-filling of both the cerebral arterial and venous systems. It allowed for the accurate observation of the normal neurovascular relationships in the posterior cranial fossa during operative simulation. Part 2 of this article concerns the use of this design in the study of trigeminal neuralgia, a disorder thought to relate to vascular compression of the fifth cranial nerve.

Reoperation for recurrent trigeminal neuralgia after microvascular decompression

BACKGROUND

Microvascular decompression (MVD) is an effective technique for those who have trigeminal neuralgia (TN) but cannot tolerate, or show no response to medicine. Though the initial success rate is high, some patients may develop severe recurrent neuralgia, especially after a longer period of follow-up. The efficacy of reoperation needs to be evaluated. To know the possible risk factors of recurrence after initial MVD is mandatory to the management of recurrent TN.

METHODS

Among the 80 cases of TN treated with MVD, five cases showed severe recurrent symptoms within a follow-up period from 9 months-4 years. The symptoms recurred on the same side of the face, and were unresponsive to medical treatment. Brain computed tomography (CT) and magnetic resonance imaging (MRI) may reveal the etiology of recurrence. Repeat decompression of the trigeminal nerve was the main goal of reoperation, which was done via a suboccipital approach.

RESULTS

Over the past 17 years, 80 MVDs for TN have been performed at Chang Gung Memorial Hospital. There were five cases of serious postoperative recurrence, which could not be relieved by medicine. Recurrence occurred 1 day-12 months after the initial surgery. Three cases were due to vascular compression, while two were caused by the local effect of Teflon felt. Reoperation produced complete remission in four patients, and partial remission in one.

CONCLUSIONS

An increasing number of patients may experience severe recurrent TN after initial MVD during a long period of follow-up. Reoperation is safe and beneficial for these patients, but the results are dependent on the etiology of the recurrence. Further vascular compression of the trigeminal nerve can be relieved by MVD. Otherwise, in cases of severe adhesion caused by Teflon, complete microneural lysis can achieve satisfactory results.

Findings and long-term results of subsequent operations after failed microvascular decompression for trigeminal neuralgia

OBJECTIVE

To evaluate the indication of subsequent operations after failed microvascular decompression (MVD) for the treatment of trigeminal neuralgia, the intraoperative findings and long-term results of 16 subsequent operations are reported.

METHODS

Subsequent exploration of the posterior fossa was performed for lack of pain relief (3 patients) and recurrent neuralgia (13 patients) after an average of 17 months (range, 4-62 mo). In all patients, typical arterial compression patterns at the root entry zone of the trigeminal nerve were found in the first procedure. The mean follow-up period after subsequent operation was 90 months (range, 78-104 mo).

RESULTS

New arterial neurovascular conflicts were found in nine patients. After subsequent MVD procedures, seven patients were pain-free (with one recurrence after 6 mo), one had constant marked relief, and one was unchanged. Second exploration revealed no abnormalities in the other seven patients who experienced continued or recurrent pain; only careful neurolysis of the trigeminal nerve was performed in those patients. Initially, all seven patients obtained complete pain relief, but two experienced late recurrences after 64 and 68 months, respectively. Thus, subsequent operations failed in all 4 patients who had undergone prior destructive procedures but were successful in those 12 patients who had undergone only previous MVD. Two patients developed severe sequelae, and the other nine had minor complications, especially permanent (four patients) or transitory (three patients) ipsilateral trigeminal hypoesthesia.

CONCLUSION

Subsequent MVD seems to have good long-term results. However, because of the significantly high incidence of complications, the indication for subsequent operations should be restricted to younger patients to avoid destructive procedures. In general, glycerol rhizolysis or radiofrequency rhizotomy may be the treatment of choice after failed MVD.

The significance of three-dimensional MR-defined neurovascular compression for the pathogenesis of trigeminal neuralgia

Three-dimensional MR tomography was used to examine the relationship between symptoms of trigeminal neuralgia and neurovascular compression of the nerve in 18 patients. The intensity of neurovascular interaction was classified according to neuroradiological criteria. We found that a radiologically defined compression or dislocation of the nerve by an artery was always associated with symptoms of trigeminal neuralgia. A simple contact between vessel and nerve, however, was also observed on the asymptomatic sides of 10 out of 18 patients. In 6 of 18 patients, in contrast, trigeminal neuralgia was present in spite of the absence of neurovascular contact. In accordance with a cited study based on autopsy and intraoperative findings, our findings indicate that, in a certain proportion of cases, trigeminal neuralgia may be caused by neurovascular compression alone, whereas in other cases, other pathogenetic factors may be involved to a varying degree or be even exclusively responsible for the development of trigeminal neuralgia. The possible significance of the method for a preoperative estimation of the success of microvascular decompression of the trigeminal nerve is discussed.

Repeat operations in failed microvascular decompression for trigeminal neuralgia

For the study of pathogenesis and treatment of recurrent trigeminal neuralgia, we performed 31 repeat operations from among 400 patients with trigeminal neuralgia in the past 10 years. Initially, of these 400 patients, 376 underwent microvascular decompression only, and 24 underwent partial sensory rhizotomy with or without microvascular decompression. Fifty-three patients (14%) had recurrences after microvascular decompression, of which 31 patients underwent repeat operations. Among the repeat operations, there was negative exploration in 16 patients (52%), arterial loop compression in 7 (22%), venous compression in 4 (13%), and Teflon compression or adhesion in 4 (13%). Twenty-one patients had early recurrences within 1 year, and 10 patients had late recurrences. Negative exploration and arterial compression were more likely in early recurrence (P = 0.01). Continuing demyelination might occur in patients with negative exploration, even when adequate decompression had been initially performed. Seventy percent of the patients had no recurring pain by way of partial sensory rhizotomy for negative explorations, redecompression of arterial loops, division of offending veins, or lysis and reposition of Teflon. About half of the patients had positive findings that were amenable without rhizotomy in the repeat operations. A repeat operation for failed microvascular decompression is a good choice if the condition of the patient is tolerant.