Initial Microvascular Decompression Research Articles

Potential reasons for failure and recurrence in microvascular decompression for hemifacial spasm.

To examine the factors contributing to persistent and recurrent hemifacial spasms (HFS) following a microvascular decompression (MVD) procedure and to suggest technical improvements to prevent such failures. A retrospective review was conducted on fifty-two cases of repeat surgery. The extent of the previous craniotomy and the location of neurovascular compression (NVC) were investigated. The operative findings were categorized into two groups: "Missing Compression" and "Teflon Contact". The analysis included long-term outcomes and operative complications after repeat MVD procedures. Missing compression was identified in 29 patients (56%), while Teflon contact was observed in 23 patients (44%). Patients with missing compression were more likely to experience improper craniotomy (66%) compared to those with Teflon contact (48%). Medially located NVC was a frequent finding in both groups, mainly due to compression by the anterior inferior cerebellar artery. In the missing compression group, during the repeat MVD, Teflon sling retraction was utilized in 79% of cases, while in the Teflon contact group, the most common procedure involved removing the Teflon in contact (65%). After the repeat MVD procedure, immediate spasm relief was achieved in 42 patients (81%), with six (12%) experiencing delayed relief. After a median follow-up of 54 months, 96% of patients were free from spasms. Delayed facial palsy, facial weakness, and hearing impairment were more frequently observed in the Teflon contact group. A proper craniotomy that provides adequate exposure around the REZ is crucial to prevent missing the culprit vessel during the initial MVD procedure. Teflon contact on the REZ should be avoided, as it poses a potential risk of procedure failure and recurrence.

How to Improve the Effect of Microvascular Decompression for Hemifacial Spasm: A Retrospective Study of 32 Cases with Unsuccessful First Time MVD.

Microvascular decompression (MVD) has become accepted as an effective therapeutic option for hemifacial spasm (HFS); however, the curative rate of MVD for HFS varies widely (50-98%) in different medical centers. This study could contribute to the improvement of the MVD procedure. We retrospectively analyzed 32 patients in whom initial MVD failed in other hospitals and who underwent a second MVD at our center. The clinical characteristics, operative findings, outcome of the second MVD, and complications were recorded. There were 18 women and 14 men (56.3 and 43.7%, respectively). The left-to-right ratio was 19:13. The mean age of the patients was 59.8 years. We found an undiscovered conflict site located in zone 4 in 10 patients and in the root entry zone in 8 patients. The initial MVD failed in nine patients because of ignorance of the arterioles that originate from the anterior inferior cerebellar artery. There were no special findings in four patients. No Teflon felts were found in the whole surgical field in one patient. Omission of the offending vessel is the most common cause of an unsuccessful MVD. Intraoperative abnormal muscle response associated with the Z-L response is a good measure to correctly identify the involved arterioles.

Microvascular decompression as a second step treatment for trigeminal neuralgia in patients with failed two-isocentre gamma knife radiosurgery.

Subsequent microvascular decompression (MVD) might be affected by the previous two-isocentre gamma knife radiosurgery (GKS) due to the tissue changes caused by its higher dose radiation and larger treatment volume. This study aimed to evaluate the safety and efficacy of MVD as a second step treatment after two-isocentre GKS. Between December 2016 and May 2019, data from 19 consecutive trigeminal neuralgia (TN) patients who experienced MVD after failed two-isocentre GKS were collected. The clinical characteristics, intraoperative findings, surgical outcomes and complications were reviewed and compared with 158 patients who underwent MVD as an initial treatment. Fifteen patients (78.9%) achieved complete pain relief (Barrow Neurological Institute, BNI class I) immediately after surgery and nine patients (47.4%) maintained complete pain relief at the last follow-up, which was similar to patients who underwent initial MVD. The median follow-up period was 36months. The incidence of new or worsened facial numbness showed no statistical significance between the groups. During surgery, trigeminal nerve atrophy was noted in 9 patients (47.4%), thickened arachnoid in 3 patients (15.8%), atherosclerotic plaque in 3 patients (15.8%) and neurovascular adhesion in 1 patient (5.3%). MVD remains an effective and safe rescue therapy for patients who elect the minimally invasive treatment with two-isocentre GKS for the first time, without an increased risk of facial numbness.

Case report of recurrent hemifacial spasm attributed to over-impaction with Teflon sponge

Background: Hemifacial spasm (HS) is a muscular disorder frequently exacerbated by arterial compression amenable to surgical intervention through microvascular decompression (MVD). Recurrence is a known cause and warrants investigation.Case Description: A 65-year-old woman presented with the left HS of 7 years duration. Her symptoms were initially well controlled with botulinum toxin injections. However, these injections eventually lost their effectiveness, necessitating MVD. At surgery, the anterior inferior cerebellar artery was indenting the facial nerve at its root entry zone. This was carefully dissected away, and several Teflon (polytetrafluoroethylene) felt pledgets were used for decompression. Postoperatively, the patient reported great improvement of her symptoms for 3 months. Gradually her spasms returned, intermittently at first, until finally they became persistent 6 months postoperatively. An MRI was obtained showing elevation and posterior displacement of the VII-VIII complex by the pledgets. After failing to improve, the patient opted for reoperation 10 months after initial MVD. At surgery, the Teflon pledgets were displacing the VII-III nerves posteriorly and superiorly. The Teflon pledgets were dissected free, and the nerve dis-impacted. On her postoperative visit 1 year later, she is spasm free, subjectively, and objectively.Conclusion: This case illustrates the value of re-imaging recurrent HS, and re-exploration with a favorable rkesult.

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

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. 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. 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). MVD works well for HFS with cure rates >90% at 1-year follow-up in 6249 patients from 39studies. 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.

Repeat Microvascular Decompression for Trigeminal Neuralgia After Initial Microvascular Decompression: Three Cases and Literature Review

Repeat Microvascular Decompression for Trigeminal Neuralgia After Initial Microvascular Decompression: Three Cases and Literature Review

Missed Culprits in Failed Microvascular Decompression Surgery for Hemifacial Spasm and Clinical Outcomes of Redo Surgery

To identify causes of recurrent hemifacial spasm (HFS) after initial microvascular decompression (MVD) and to assess the feasibility of redo MVD. The study included 21 patients who underwent redo MVD over the last 2 decades. Their medical charts were retrospectively reviewed for preoperative medical history, previous and redo MVD intraoperative findings, and previous and redo MVD postoperative outcomes. Redo MVDs were the second operation in 20 patients and the third operation in 1 patient. The median interval between previous and redo MVD was 46.3 months (range, 14.4-188.2 months). Compression of offending vessels such as a vein or perforating artery located medial to or at the cisternal segment of the facial nerve was found to be a possible cause of previous MVD failure. MVD failure resulted from neglect of offending vessels in 10 patients, insufficient decompression in 7 patients, and untouched neurovascular compression sites in 4 patients. Spasm-free rates after redo MVD were 80.5% at 1 year and 90.5% in the last year of follow-up (median, 15.8 months; range, 3.6-152.0 months). Permanent hearing loss and facial palsy were each observed in 2 patients (9.5%). In addition, 1 patient each experienced cerebellar infarction and vocal cord palsy. Redo MVD remains a feasible treatment option for patients with HFS who failed to benefit from previous MVD, but it is associated with an increased risk of cranial nerve and vascular injuries.

Repeat microvascular decompression for patients with persistent or recurrent trigeminal neuralgia: Prognostic factors and long-term outcomes.

Patients with persistent or recurrent trigeminal neuralgia (TN) after microvascular decompression (MVD) are frequently difficult to manage. This study aimed to analyze the safety and efficiency of repeat MVD, with the main focus on prognostic factors and long-term outcomes.We performed a retrospective study of 41 TN patients (19 men, 22 women) who underwent repeat MVD due to persistent or recurrent pain from January 2008 to January 2016. These patients were followed up from 12 to 96 months (mean, 42 ± 17.3 months). Univariate analysis by Spearman's rank correlation coefficient was used for analysis of prognostic factors.During the repeat MVD, compression of the trigeminal nerve was noted by an artery in 15 patients (36.6%), vein in 6 patients (14.6%), Teflon in 8 patients (19.5%), and no compression in 12 patients (29.3%). Twenty-one patients (51.2%) had already undergone 1 or more previous ablative procedures, either before the first MVD or between the surgeries. The complete pain relief rates of repeat MVD were 87.8% immediately after surgery and 75% at last follow-up. Thirteen patients (31.7%) had new or increased facial numbness after repeat surgery. Univariate analysis revealed 2 prognostic factors, negative finding during reoperation (P = .021) and no pain relief after the initial surgery (P = .038), that showed a negative influence on success rates after repeat MVD.Repeat MVD can still achieve an excellent outcome in patients with persistent or recurrent pain. However, the risk of facial numbness is increased. Surgeons should be selective in performing repeat MVD, priority should be given to patients who have a pain-free interval after initial MVD or show demonstrable compression on imaging studies.

Revision Microvascular Decompression for Trigeminal Neuralgia and Hemifacial Spasm: Factors Associated with Surgical Failure.

Objective To investigate risk factors for symptom recurrence in patients requiring a revision microvascular decompression (MVD) for trigeminal neuralgia (TN) or hemifacial spasm (HFS). Design Retrospective review of a prospectively maintained database. Participants Seventeen consecutive patients undergoing revision MVD at our institution between January 1993 and September 2017. Main Outcome Measures The incidence and causes for revision MVDs were recorded. Response to revision MVD for TN was tracked using the Barrow Neurological Institute (BNI) grading scale. Response to revision MVD for HFS was graded as "no improvement," "some relief," or "complete resolution" of symptoms. Results Revision MVD rate for the senior author across all MVDs performed in this period was 1.9% for TN and 9.3% for HFS. Initial MVD failure was primarily caused by active inflammation and/or scarring and adhesions in 5/17 patients, malposition/slippage of Teflon in 3/17 patients, and insufficient Teflon in 1/17 patients. Without other factors, a new site of neurovascular conflict was identified in 4/17 patients, while the same site of neurovascular conflict was found in 3/17 patients. No cause could be identified in 1/17 patients. Scarring was found primarily in the TN group and was associated with symptom persistence. Conclusion Revision MVD for recurrent TN and HFS is an effective procedure offering the prospect of a complete cure. Proper Teflon use is crucial for surgical success. Scarring after initial MVD is a negative prognostic factor requiring destructive treatment consideration. Although morbidity rates were slightly increased with revision versus original MVDs, the complications were non-disabling and resolved over time.

Long-Term Efficacy of Nerve Combing for Patients with Trigeminal Neuralgia and Failed Prior Microvascular Decompression.

Microvascular decompression (MVD) of the trigeminal nerve is the most effective treatment for trigeminal neuralgia (TN). However, many patients respond poorly to initial MVD. For these patients, redo MVD is commonly done. There has been no research regarding the effectiveness of nerve combing (NC) plus MVD in patients with TN and failed prior MVD. We compared the clinical outcome of NC plus MVD and simple redo MVD in patients with TN and failed prior MVD. We performed a retrospective analysis of 148 patients with recurrent or persistent TN symptoms who underwent surgery between January 2007 and December 2015. Simple MVD was performed in 62 patients, and NC plus MVD was performed in 86 patients. For simple MVD, success rates at 1 day, 7 days, 1 month, 3 months, and 1 year after surgery all were approximately 80%. Success rates of NC plus MVD were significantly (P < 0.05) higher than success rates of simple MVD, by 17.02%, 18.64%, 16.47%, 17.21%, and 14.80% at 1 day, 7 days, 1 month, 3 months, and 1 year. The incidence rates of facial numbness in the simple MVD group were 48.39%, 45.16%, 36.67%, 16.95%, and 1.75% at 1 day, 7 days, 1 month, 3 months, and 1 year; the incidence rates in the NC plus MVD group were 60.47%, 55.81%, 48.24%, 21.69%, and 3.75% (P > 0.05). In patients with TN who failed prior MVD, NC plus MVD significantly improved the success rate of the operation compared with simple redo MVD. We obtained good short-term and long-term surgical outcomes with NC combined with MVD.

Efficacy of primary microvascular decompression versus subsequent microvascular decompression for trigeminal neuralgia.

OBJECTIVE Trigeminal neuralgia (TN) is characterized by intermittent, paroxysmal, and lancinating pain along the distribution of the trigeminal nerve. Microvascular decompression (MVD) directly addresses compression of the trigeminal nerve. The purpose of this study was to determine whether patients undergoing MVD as their first surgical intervention experience greater pain control than patients who undergo subsequent MVD. METHODS A retrospective review of patient records from 1998 to 2015 identified a total of 942 patients with TN and 500 patients who underwent MVD. After excluding several cases, 306 patients underwent MVD as their first surgical intervention and 175 patients underwent subsequent MVD. Demographics and clinicopathological data and outcomes were obtained for analysis. RESULTS In patients who underwent subsequent MVD, surgical intervention was performed at an older age (55.22 vs 49.98 years old, p < 0.0001) and the duration of symptoms was greater (7.22 vs 4.45 years, p < 0.0001) than for patients in whom MVD was their first surgical intervention. Patients who underwent initial MVD had improved pain relief and no improvement in pain rates compared with those who had subsequent MVD (95.8% and 4.2% vs 90.3% and 9.7%, respectively, p = 0.0041). Patients who underwent initial MVD had significantly lower rates of facial numbness in the pre- and postoperative periods compared with patients who underwent subsequent MVD (p < 0.0001). The number of complications in both groups was similar (p = 0.4572). CONCLUSIONS The results demonstrate that patients who underwent other procedures prior to MVD had less pain relief and a higher incidence of facial numbness despite rates of complications similar to patients who underwent MVD as their first surgical intervention.

Gamma Knife surgery for recurrent or residual trigeminal neuralgia after a failed initial procedure

The purpose of this study was to assess outcomes of Gamma Knife surgery (GKS) as a second treatment for recurrent or residual trigeminal neuralgia (TN) after failure of 3 initial procedures: microvascular decompression (MVD), GKS, and percutaneous radiofrequency rhizotomy (PRR). Between 1999 and 2008, 65 patients (31 men [48%] and 34 women [52%]) with recurrent TN were treated with GKS. All 65 patients had undergone previous medical procedures that failed to achieve sufficient pain relief: 27 patients (42%) had undergone MVD, 8 (12%) had undergone PRR, and 30 (46%) had undergone GKS as the initial treatment. The entry zone of the trigeminal nerve was targeted using a 4-mm collimator and treated with 35-90 Gy. The isocenter was positioned so that the brainstem surface was usually irradiated at an isodose no greater than 20% (59 patients) to 30% (6 patients). The median duration of TN symptoms in these patients was 39 months (range 1-192 months). At the clinical evaluation, 42 patients (65%) with idiopathic TN reported successful pain control at a median follow-up point of 64 months (range 18-132 months). Of these patients, 33 (51%) were no longer using medication. At the 1-, 2-, and 3-year follow-up examinations, 74%, 71%, and 66% of patients experienced successful pain control, respectively. There was no significant difference in pain relief in the initial MVD group compared with the initial GKS and initial PRR groups (74% vs 59% and 50%, respectively; p = 0.342). Recurrence of pain was noted in 23 patients. Twelve of these 23 patients underwent another GKS, resulting in pain control in 8 patients (67%); 8 other patients underwent MVD, resulting in pain relief in 7 patients (87.5%). The median time from GKS to pain recurrence was 7 months (range 3-48 months). There was no significant difference in new facial numbness among the 3 groups (p = 0.24); however, in the initial GKS group, facial numbness was significantly associated with freedom from pain (p = 0.0012). There was a significant correlation between the total radiation dose and facial numbness. The cutoff value for facial numbness ranged from 115 to 120 Gy (p = 0.037). Gamma Knife surgery as a second treatment achieved acceptable levels of pain control in 65% of patients with residual or recurrent TN after long-term follow-up. Initial treatment was not a factor that affected pain control, but salvage surgery may be considered separately for each group.

EFFECT OF MICROVASCULAR DECOMPRESSION IN TRIGEMINAL NEURALGIA PATIENTS WITH OR WITHOUT CONSTANT PAIN

To study the effect of microvascular decompression (MVD) in trigeminal neuralgia (TN) patients with or without constant pain. The study includes all first-time MVDs for facial pain performed by the senior author (PKE) during the 6-year period from 1999 to 2005 in the Department of Neurosurgery at the National Hospital. At the time of follow-up, pain relief was assessed using a standard mail questionnaire; those patients still having residual pain were further examined in the outpatient clinic or interviewed by phone. The total study population includes 135 patients who underwent initial MVDs (67% of MVDs for TN without constant pain and 33% of MVDs for TN with constant pain). At the time of follow-up, the response rate was 95%, which provided us with 128 patients. The median observation period was 38 months (range, 12-87 mo). For episodic pain, MVD caused complete (i.e., 100%) pain relief in 78% of TN patients without constant pain and in 77% of TN patients with constant pain before MVD, and a significant pain relief (i.e., worst pain marked as 0-3 cm on a 10-cm visual analog scale) in 85 and 81%, respectively. For constant pain, MVD caused complete pain relief in 70% of the TN patients with constant pain before MVD, and significant pain relief in 77%. In TN patients with constant pain before MVD, significant relief of episodic and constant pain was observed in 81 and 77%, respectively. Hence, the presence of constant pain should not prevent TN patients from being offered MVD.

Recurrent trigeminal neuralgia attributable to veins after microvascular decompression.

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. 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. 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. 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 as treatment of trigeminal neuralgia in the elderly patient.

Elderly patients with idiopathic trigeminal neuralgia are commonly referred to percutaneous treatment if medical therapy has failed. Due to elaborated microsurgical techniques and perioperative care, minimal invasive neurosurgical operations like microvascular decompression (MVD) can be offered increasingly to elderly patients. We operated upon 8 elderly patients (median 70.5 years) suffering from trigeminal neuralgia using MVD in a one-year period (1995). Seven patients were free of pain at release. At a two year follow-up, 2 patients reported of slight dull pain in the trigeminal area, one of these had been pretreated with retrogasserian glycerol rhizolysis and an initial MVD procedure four years before this decompression. All patients were still off medication (analgetics and anticonvulsants), indicating that all patients experienced an excellent (6/8) or a good (2/8) result two years after MVD. One CSF fistula requiring reoperation was the only complication. After failure of medical therapy for symptomatic trigeminal neuralgia, we encourage elderly patients to undergo MVD if the general medical condition is stable and complete pain relief without medication is the requested aim of treatment.