Technique of microvascular decompression

Developing a high fidelity, low cost simulation model for retrosigmoid craniotomy and microvascular decompression of the trigeminal nerve

BACKGROUND

Trigeminal neuralgia is a very painful condition that may require a surgical approach as treatment, which is typically retrosigmoid craniotomy followed by microvascular decompression. Due to the limited margin for error when operating in the small triangular window of the cerebellopontine angle and the infrequency of this condition, the operating room can present a difficult learning environment for surgical trainees. Our aim is to create a synthetic, low-cost, high-fidelity, and largely reusable simulation model that will enable neurosurgical trainees to practice these procedural steps in a safe learning environment.

MATERIALS AND METHODS

Design-based research was employed to develop the model through iterative micro-cycles, with expert evaluation from an educational and clinical team. The model was made from easy to source materials without advanced technology where sustainability, reproduction at scale and cost where significant considerations.

RESULTS

Our model effectively simulates a retrosigmoid craniotomy and microvascular decompression of the trigeminal nerve. The model consists of two distinct parts that are made of synthetic materials. Part A is a single-use, moulded portion of the skull, while part B depicts the cerebellopontine angle and some of its internal anatomical and pathological structures crucial to carrying out all the steps to this procedure. Part A sits ergonomically flush on top of Part B, with both parts subsequently clamped to the table.

CONCLUSIONS

As a proof of concept, we report the development and utilisation of a novel, low-cost, replicable retrosigmoid craniotomy and microvascular decompression of the trigeminal nerve simulation model.

Outcomes of Different Surgical Interventions for Treating Trigeminal Neuralgia: A Review

Trigeminal neuralgia (TN) is a debilitating condition characterized by severe facial pain. Various surgical interventions are employed to manage this condition, including microvascular decompression (MVD), percutaneous radiofrequency rhizotomy (PRR), glycerol rhizotomy, percutaneous balloon compression (PBC), and stereotactic radiosurgery such as Gamma Knife radiosurgery (GKRS). This review synthesizes the outcomes of these interventions to provide an understanding of their efficacy and associated risks. MVD, known for its high initial relief rates, shows substantial long-term effectiveness, with recurrence rates varying based on patient demographics and comorbidities. GKRS offers significant pain relief with a favorable adverse event profile; however, recurrence rates increase over time, necessitating repeat procedures for sustained efficacy. PBC demonstrates high initial success, but pain recurrence is common, especially in patients with atypical TN. PRR provides immediate relief with a manageable recurrence rate and is particularly suitable for elderly patients and those with comorbidities. Glycerol rhizotomy, a cost-effective procedure, yields comparable outcomes to other interventions but requires careful patient selection. This review highlights the importance of tailored treatment approaches based on individual patient profiles, emphasizing the need for precise diagnostic criteria and careful patient selection to optimize outcomes. Long-term follow-up and the potential for repeat interventions are critical considerations in managing TN surgically.

Sumatriptan for Postcraniotomy Headache after Minimally Invasive Craniotomy for Clipping of Aneurysms: A Prospective Randomized Controlled Trial

Introduction  Postcraniotomy headaches are often underestimated and undertreaded. This study aimed to identify if postoperative administration of sumatriptan after minimally invasive craniotomy for clipping an unruptured aneurysm could reduce postcraniotomy headache and improve the quality of postoperative recovery. Settings and Design  Tertiary care center, single-center randomized double-blind placebo-controlled trial. Materials and Methods  Patients who complained of postoperative headaches after minimally invasive craniotomy for clipping of unruptured aneurysms were randomized to receive subcutaneous sumatriptan (6 mg) or placebo. The primary outcome was the quality of recovery measured 24 hours after surgery. Secondary outcomes were total opioid use and headache score at 24 hours after surgery. Data were analyzed using a Student's t -test or the chi-square test. Results  Forty patients were randomized to receive sumatriptan ( n  = 19) or placebo ( n  = 21). Both groups had similar demographics, comorbidities, and anesthesia management. The Quality of Recovery 40 score was higher for patients receiving sumatriptan compared to placebo, however, not statistically significant (173 [156-196] vs. 148 [139-181], p  = 0.055). Postoperative opioid use between sumatriptan and placebo was lower, but not significant (5.4 vs. 5.6 mg morphine equivalent, p  = 0.71). The severity of headache was also not statistically different between the two groups (5 [4-5] vs. 4 [2-5], p  = 0.155). Conclusion  In patients undergoing minimally invasive craniotomies for aneurysm clipping, sumatriptan given postoperatively has a nonsignificant trend for a higher quality of recovery. Similarly, there was a nonsignificant trend toward lower postcraniotomy headache scores and opioid scores for the patient given sumatriptan.

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

Background

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

Methods

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

Results

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

Conclusions

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

Anatomical measurements of trigeminal ganglion: a cadaver study

It is difficult to obtain specific information regarding the trigeminal ganglion (TG), especially pediatric TG. The aim of present study was to determine the parameters of the TG and assist in the neuroablative treatment of trigeminal neuralgia (TN). Thirty-seven sides of cadaver heads that had undergone gross anatomical examination were included, with 29 sides of adults and 8 sides of infants. The distance and angles were measured among 12 points, with nine points adjacent to the TG and three points on the foramen ovale (FO). The three points on FO were represented as three different surgical approaches for TN: posterior FO approach (PFO), lateral FO approach (LFO), and anterior FO approach (AFO). A high similarity was found in pediatric TG. No statistical difference was detected in either the distance or the angles between the 12 points. Statistical difference was found in adult heads in some of the distances, which included PFO to point 5 (17.97 ± 3.35 mm in the left and 15.52 ± 2.28 mm in the right; p = 0.03) and LFO to point 5 and point 8. Moreover, the angle for PFO to point 5 showed a statistically significant difference (60.10 ± 14.02 in the left and 46.63 ± 10.48 in the right; p = 0.01). These findings revealed that surgical neuroablation for patients with TN should be performed more carefully when the PFO or LFO approach is adopted, with a precise preoperative evaluation to avoid corneal complications. Two safety radiofrequency rhizotomy points are also presented to deal with two different kinds of TN.

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.

Posterior Fossa Volume and Dimensions: Relation to Pathophysiology and Surgical Outcomes in Classic Trigeminal Neuralgia

OBJECTIVE

A small posterior fossa (PF) has been hypothesized to explain the increased incidence of trigeminal neuralgia (TN) in females and could make microvascular decompression (MVD) more challenging. The aim of this study was to investigate the association between the PF volume and dimensions in relation to biological sex, type of neurovascular conflict (NVC), and outcome after MVD in classic TN.

METHODS

In this observational study, 84 patients with TN operated on with MVD with a preoperative head computed tomography(CT) scan were included. Eighty-two adults without TN who had undergone head CT for other reasons were included as controls. PF volume and dimensions (x-axis, y-axis, and z-axis) were evaluated on the CT scans. For the patients with TN, Barrow Neurological Institute (BNI) grade was evaluated 6 months after MVD.

RESULTS

There was no difference in PF volume or dimensions between the patients with TN and controls. Women showed a smaller volume and narrower (x-axis) PF than men, but these differences did not manifest when comparing patients with TN and controls within each sex. Patients with an NVC involving the superior cerebellar artery had a narrower (x-axis) and shorter (y-axis) PF than did patients with an NVC resulting from other arteries. PF volume or dimensions were not associated with BNI grade after MVD.

CONCLUSIONS

PF anatomy was related to the NVC type but did not differ between patients with TN and controls and was not related to the surgical outcome after MVD.

Minimally Invasive Retrosigmoidal Parasterional Burr-Hole Approach: Technique and Neuropathic Pain Amelioration after Microvascular Decompression of the Trigeminal Nerve

BACKGROUND

Trigeminal neuralgia, a common condition in clinical practice, often occurs due to vascular compression caused by aberrant or ectopic arterial or venous vessels. Microvascular decompression through a minimally invasive retrosigmoidal approach has shown high rates of pain control, low complication rates, and excellent therapeutic results.

OBJECTIVE

To describe the surgical technique and clinical outcomes in terms of pain relief after microvascular decompression of the trigeminal nerve through a minimally invasive retrosigmoidal parasterional burr-hole technique.

METHODS

A group of patients with trigeminal neuralgia refractory to medical management who underwent microvascular decompression were examined. The records of the patients were considered retrospectively (2016-2018), and the outcomes were considered based on the Visual Analogue Scale (VAS) and the Barrow Neurological Institute Pain Scale (BNIPS) added to a technical note of the surgical technique for a minimally invasive retrosigmoidal parasterional burr-hole.

RESULTS

Twenty-two patients were evaluated, and clinical assessment after surgical intervention showed a decrease in pain according to the VAS, resulting from an average preoperative state of 9.5 ± 0.37 to a postoperative condition of 1.32 ± 1.28, exhibiting statistically significant changes (p < 0.0001, d = 9.356). On the other hand, in relation to the BNIPS scale, a decrease from an average preoperative status of 4.55 ± 0.25 to a postoperative status at 12 months of 1.73 ± 0.54 was also demonstrated, showing significant changes (p < 0.0001, d = 3.960).

CONCLUSION

Microvascular decompression of the trigeminal nerve through a minimally invasive retrosigmoidal parasterional burr-hole is feasible and can be a safe and effective technique for the management of pain. However, further research employing larger sample sizes and longer follow-up periods is necessary.

Benchtop simulation of the retrosigmoid approach: Validation of a surgical simulator and development of a task-specific outcome measure score

Background

Neurosurgical training is changing globally. Reduced working hours and training opportunities, increased patient safety expectations, and the impact of COVID-19 have reduced operative exposure. Benchtop simulators enable trainees to develop surgical skills in a controlled environment. We aim to validate a high-fidelity simulator model (RetrosigmoidBox, UpSurgeOn) for the retrosigmoid approach to the cerebellopontine angle (CPA).

Methods

Novice and expert Neurosurgeons and Ear, Nose, and Throat surgeons performed a surgical task using the model - identification of the trigeminal nerve. Experts completed a post-task questionnaire examining face and content validity. Construct validity was assessed through scoring of operative videos employing Objective Structured Assessment of Technical Skills (OSATS) and a novel Task-Specific Outcome Measure score.

Results

Fifteen novice and five expert participants were recruited. Forty percent of experts agreed or strongly agreed that the brain tissue looked real. Experts unanimously agreed that the RetrosigmoidBox was appropriate for teaching. Statistically significant differences were noted in task performance between novices and experts, demonstrating construct validity. Median total OSATS score was 14/25 (IQR 10-19) for novices and 22/25 (IQR 20-22) for experts (p < 0.05). Median Task-Specific Outcome Measure score was 10/20 (IQR 7-17) for novices compared to 19/20 (IQR 18.5-19.5) for experts (p < 0.05).

Conclusion

The RetrosigmoidBox benchtop simulator has a high degree of content and construct validity and moderate face validity. The changing landscape of neurosurgical training mean that simulators are likely to become increasingly important in the delivery of high-quality education. We demonstrate the validity of a Task-Specific Outcome Measure score for performance assessment of a simulated approach to the CPA.

Supratentorial cerebrospinal fluid diversion using image-guided trigonal ventriculostomy during retrosigmoid craniotomy for cerebellopontine angle tumors

Background

Cerebellar contusion, swelling and herniation is frequently encoutered upon durotomy in patients undergoing retrosigmoid craniotomy for cerebellopontine angle (CPA) tumors, despite using standard methods to obtain adequate cerebellar relaxation.

Objective

The aim of this study is to report an alternative cerebrospinal fluid (CSF)-diversion method using image-guided ipsilateral trigonal ventriculostomy.

Methods

Single-center retro- and prospective cohort study of n = 62 patients undergoing above-mentioned technique. Prior durotomy, CSF-diversion was performed to the point where the posterior fossa dura was visibly pulsatile. Outcome assessment consisted of the surgeon's intra- and postoperative clinical observations, and postoperative radiological imaging.

Results

Fifty-two out of n = 62 (84%) cases were eligible for analysis. The surgeons consistently reported successful ventricular puncture and a pulsatile dura prior durotomy without cerebellar contusion, swelling or herniation through the dural incision in n = 51/52 (98%) cases. Forty-nine out of n = 52 (94%) catheters were placed correctly within the first attempt, with the majority of catheter tips (n = 50, 96%) located intraventricularly (grade 1 or 2). In n = 4/52 (8%) patients, postoperative imaging revealed evidence of a ventriculostomy-related hemorrhage (VRH) associated with an intracerebral hemorrhage [n = 2/52 (4%)] or an isolated intraventricular hemorrhage [n = 2/52 (4%)]. However, these hemorrhagic complications were not associated with neurological symptoms, surgical interventions or postoperative hydrocephalus. None of the evaluated patients demonstrated radiological signs of upward transtentorial herniation.

Conclusion

The method described above efficiently allows CSF-diversion prior durotomy to reduce cerebellar pressure during retrosigmoid approach for CPA tumors. However, there is an inherent risk of subclinical supratentorial hemorrhagic complications.

Sacrifice or preserve the superior petrosal vein in microvascular decompression surgery: a systematic review and meta-analysis

OBJECTIVE

In microvascular decompression (MVD) surgery through the retrosigmoid approach, the surgeon may have to sacrifice the superior petrosal vein (SPV). However, this is a controversial maneuver. To date, high-level evidence comparing the operative outcomes of patients who underwent MVD with and without SPV sacrifice is lacking. Therefore, this study sought to bridge this gap.

METHODS

The authors searched the Medline and PubMed databases with appropriate Medical Subject Heading (MeSH) terms and keywords. The primary outcome was vascular-related complications; secondary outcomes were new neurological deficit, cerebrospinal fluid (CSF) leak, and neuralgia relief. The pooled proportions of outcomes and OR (95% CI) for categorical data were calculated by using the logit transformation and Mantel-Haenszel methods, respectively.

RESULTS

Six studies yielding 1143 patients were included, of which 618 patients had their SPV sacrificed. The pooled proportion (95% CI) values were 3.82 (0.87-15.17) for vascular-related complications, 3.64 (1.0-12.42) for new neurological deficits, 2.85 (1.21-6.58) for CSF leaks, and 88.90 (84.90-91.94) for neuralgia relief. The meta-analysis concluded that, whether the surgeon sacrificed or preserved the SPV, the odds were similar for vascular-related complications (2.5% vs 1.5%, OR [95% CI] 1.01 [0.33-3.09], p = 0.99), new neurological deficits (1.2% vs 2.8%, OR [95% CI] 0.55 [0.18-1.66], p = 0.29), CSF leak (3.1% vs 2.1%, OR [95% CI] 1.16 [0.46-2.94], p = 0.75), and neuralgia relief (86.6% vs 87%, OR [95% CI] 0.96 [0.62-1.49], p = 0.84).

CONCLUSIONS

SPV sacrifice is as safe as SPV preservation. The authors recommend intentional SPV sacrifice when gentle retraction fails to enhance surgical field visualization and if the surgeon encounters SPV-related neurovascular conflict and/or anticipates impeding SPV-related bleeding.

Deep Learning Based Real-Time Semantic Segmentation of Cerebral Vessels and Cranial Nerves in Microvascular Decompression Scenes

Automatic extraction of cerebral vessels and cranial nerves has important clinical value in the treatment of trigeminal neuralgia (TGN) and hemifacial spasm (HFS). However, because of the great similarity between different cerebral vessels and between different cranial nerves, it is challenging to segment cerebral vessels and cranial nerves in real time on the basis of true-color microvascular decompression (MVD) images. In this paper, we propose a lightweight, fast semantic segmentation Microvascular Decompression Network (MVDNet) for MVD scenarios which achieves a good trade-off between segmentation accuracy and speed. Specifically, we designed a Light Asymmetric Bottleneck (LAB) module in the encoder to encode context features. A Feature Fusion Module (FFM) was introduced into the decoder to effectively combine high-level semantic features and underlying spatial details. The proposed network has no pretrained model, fewer parameters, and a fast inference speed. Specifically, MVDNet achieved 76.59% mIoU on the MVD test set, has 0.72 M parameters, and has a 137 FPS speed using a single GTX 2080Ti card.

Prevention of Superior Petrosal Vein Injury during Microvascular Decompression for Trigeminal Neuralgia: Operative Nuances

Background The superior petrosal vein (SPV) often obscures the surgical field or bleeds during microvascular decompression (MVD) for the treatment of trigeminal neuralgia. Although SPV sacrifice has been proposed, it is associated with multiple complications. We have performed more than 4,500 MVDs, including approximately 400 cases involving trigeminal neuralgia. We aimed to describe our operative technique and nuances to avoid SPV injury.

Methods We have provided a detailed description of our institutional protocol, including the anesthesia technique, neurophysiologic monitoring, patient positioning, surgical approach, and SPV management. The surgical outcomes and treatment-related complications were retrospectively analyzed.

Results No SPVs were sacrificed intentionally or accidentally during our MVD protocol for trigeminal neuralgia. In the 344 operations performed during 2006 to 2020, 269 (78.2%) patients did not require medication postoperatively, 58 (16.9%) tolerated the procedure with adequate medication, and 17 (4.9%) did not respond to MVD. Postoperatively, 35 (10.2%), 1 (0.3%), and 0 patients showed permanent trigeminal, facial, or vestibulocochlear nerve dysfunction, respectively. Wound infection occurred in five (1.5%) patients, while cerebrospinal fluid leaks occurred in three (0.9%) patients. Hemorrhagic complications appeared in four (1.2%) patients but these were unrelated to SPV injury. No surgery-related mortalities were reported.

Conclusion MVD for the treatment of trigeminal neuralgia can be achieved safely without sacrificing the SPV. A key step is positioning the patient's vertex at a 10-degree elevation from the floor, which can ease venous return and loosen the SPV, making it less fragile to manipulation and providing a wider surgical corridor.

A Laboratory Investigation on a Tailored Skin and Muscle Flap Variant for the Retrosigmoid Approach

Introduction An anatomical study was conducted to test a modified C-shaped flap designed for patients undergoing a keyhole approach and/or minicraniotomy for retrosigmoid approach (KRSA).

Materials and Methods Ten heads specimens were used. The surgical technique investigated was based on a 4-cm C-shaped skin incision with medial convexity (placed 8 cm laterally to the external occipital protuberance, with the lower edge terminating 1.5 to 2 cm above the mastoid tip), which followed by careful subperiosteal dissection and completed by reflecting and securing the skin flap layer anteriorly and the muscle flaps superiorly and inferiorly by stitches. Anatomical findings, including depth of surgical corridor till to the cerebellopontine cistern (CPC) as well as the sparing of neurovascular structures, were evaluated in every specimen.

Results Twenty surgical approaches to CPC were conducted, resulting in a short working distance to the target (32 mm) without any need for a self-retaining retractor. In every specimen, the integrity of occipital muscles and cutaneous nerves was maintained, and a solid multilayer closure was always achieved. These data suggest that landmarks-based design of this C-shaped incision could be helpful in avoiding damages to the soft tissues encountered during KRSA.

Conclusion This modified approach provides a wide surgical corridor to access the CPC while ensuring the minimal invasiveness of the standard S-shaped incision. Compared with the latter, it preserves better the integrity of the surrounding soft tissues and appears less likely to cause any iatrogenic injury to occipital muscles and cutaneous nerves.

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

OBJECTIVE

To investigate use of multidata analysis based on an artificial neural network (ANN) to predict long-term pain outcomes after microvascular decompression (MVD) in patients with trigeminal neuralgia (TN) and to explore key predictors.

METHODS

Perioperative and long-term follow-up multidata of 1041 patients with TN who received MVD surgery at Hangzhou First People's Hospital from March 2013 to May 2018 were collected to construct an ANN model for prediction. The prediction results were compared with the actual follow-up outcomes, and the variables in each input layer were changed to test the effectiveness of ANN and explore the factors that had the greatest impact on prediction accuracy.

RESULTS

The ANN model could predict the long-term pain outcomes after MVD in patients with TN with an accuracy rate of 95.2% and area under the curve of 0.862. Four factors contributed the most to the predictive performance of the ANN: whether the neurovascular offending site of the trigeminal nerve corresponded the region of facial pain, immediate postoperative pain remission after MVD, degree of nerve compression by culprit vessels, and the type of culprit vessels. After these factors were sequentially removed, the accuracy of the ANN model decreased to 74.5%, 78.6%, 87.2%, and 90.1%, while the area under the curve was 0.705, 0.761, 0.793, and 0.810.

CONCLUSIONS

The ANN model, constructed using multiple data, predicted long-term pain prognosis after MVD in patients with TN objectively and accurately. The model was able to assess the importance of each factor in the prediction of pain outcome.

Cerebrospinal Fluid in Classical Trigeminal Neuralgia: An Exploratory Study on Candidate Biomarkers

Trigeminal neuralgia (TN) is a severe type of facial pain. A neurovascular conflict between cranial nerve V and a nearby vessel is the main pathophysiological mechanism, but additional factors are likely necessary to elicit TN. In this study, the primary aim was to explore differences in protein expression in the cerebrospinal fluid (CSF) of TN patients in relation to controls. Methods: Sixteen TN patients treated with microvascular decompression and 16 control patients undergoing spinal anesthesia for urological conditions were included. Lumbar CSF was collected preoperatively for the TN patients and before spinal anesthesia for the controls. A multiplexed proximity extension analysis of 91 CSF proteins was conducted using Proseek Multiplex Development 96, including biomarkers of cell communication, cell death, neurogenesis, and inflammation Results: The TN patients and the controls were of similar age, sex, and burden of co-morbidities. The TN patients exhibited higher concentrations of Clec11a, LGMN, MFG-E8, and ANGPTL-4 in CSF than the controls (q < 0.05). Conclusions: TN patients exhibited increased CSF biomarkers indicative of peripheral demyelinating injury (Clec11a), immune tolerance and destruction of myelin (LGMN), neuronal cell death (MFG-E8), and disturbances in myelin clearance (ANGPTL-8). Our findings are hypothesis-generating for candidate biomarkers and pathophysiological processes in classical TN.

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSION

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

Trigeminal neuralgia and other cranial pain syndromes

Spontaneous Trigeminal Neuralgia is a painful condition of the face which may require interventional treatment if medicines fail to control the pain. These include microvascular decompression (MVD) and GKNS. The former is moderately more effective but GKNS has become accepted both as an alternative to MVD or as an adjunct. Like all treatments of the condition, it is successful in a majority of patients but by no means all. Repeat treatments are possible. When Trigeminal Neuralgia is secondary to other conditions the response to GKNS is different. With AVMs, Dural Arteriovenous Fistulae and Epidermoids, the dose to treat the visible lesion usually cures the neuralgia. With meningiomas it is necessary to treat the neuralgia as a separate entity with a neuralgia dose focused on the nerve. GKNS does not improve the rare neuralgia associated with Vestibular Schwannomas. It works with Multiple Sclerosis but not as well as with the spontaneous illness. There is some evidence that GKNS can be useful with the rare Glossopharyngeal and Sphenopalatine Neuralgias.

[Trigeminal Neuralgia - What Do We Know about the Causes, Diagnosis and Treatment?]

Trigeminal Neuralgia - What Do We Know about the Causes, Diagnosis and Treatment? Abstract. Classical trigeminal neuralgia is typically characterized by a stimulus-evoked, recurrent and intense short-lasting stabbing pain in the innervation area of the trigeminal nerve. Its intensity is among the most severe pain imaginable in humans, and yet it is often misdiagnosed and undertreated. Triggers are common activities of daily life like talking or eating. The classical trigeminal neuralgia is due to a neurovascular compression at the nerve root entry zone. The secondary form is related to an underlying neurological disease (caused for example by multiple sclerosis or compression by a brain tumor); the etiology of the idiopathic trigeminal neuralgia is unknown. Treatment options include both medication (mostly antiepileptic drugs) and escalated interventional approaches (microvascular decompression, neurolesional percutaneous procedures, neuromodulative therapeutic options and radiosurgery).

Trigeminal Neuralgia: Current Approaches and Emerging Interventions

Trigeminal neuralgia (TN) has been described in the literature as one of the most debilitating presentations of orofacial pain. This review summarizes over 150 years of collective clinical experience in the medical and surgical treatment of TN. Fundamentally, TN remains a clinical diagnosis that must be distinguished from other types of trigeminal neuropathic pain and/or facial pain associated with other neuralgias or headache syndromes. What is increasingly clear is that there is no catch-all medical or surgical intervention that is effective for all patients with trigeminal neuralgia, likely reflective of the fact that TN is likely a heterogenous group of disorders that jointly manifests in facial pain. The first-line treatment for TN remains anticonvulsant medical therapy. Patients who fail this have a range of surgical options available to them. In general, microvascular decompression is a safe and effective procedure with immediate and durable outcomes. Patients who are unable to tolerate general anesthesia or whose medical comorbidities preclude a suboccipital craniectomy may benefit from percutaneous methodologies including glycerol or radiofrequency ablation, or both. For patients with bleeding diathesis due to blood thinning medications who are ineligible for invasive procedures, or for those who are unwilling to undergo open surgical procedures, radiosurgery may be an excellent option-provided the patient understands that maximum pain relief will take on the order of months to achieve. Finally, peripheral neurectomies continue to provide an inexpensive and resource-sparing alternative to pain relief for patients in locations with limited economic and medical resources. Ultimately, elucidation of the molecular mechanisms underlying trigeminal neuralgia will pave the way for novel, more effective and less invasive therapies.

Does the Surgical Intervention for Trigeminal Neuralgia Refractory to Pharmacotherapy Improve Quality-of-Life? - A Systematic Review

PURPOSE

Trigeminal neuralgia (TN) refractory to pharmacotherapy requires surgical interventions which vary from percutaneous procedure to microvascular decompression (MVD). The aim of the systematic review is to find evidence for the surgical treatment for TN with high success rate and low complications which improves the quality-of-life (QOL).

METHODS

A systematic literature search was made on published studies from MEDLINE, SCOPUS, Science direct, and Cochrane Library databases that report the available surgical treatment for TN up to March 2020 and studies referred in the selected papers. Relevant studies were selected based on predefined eligibility criteria. The primary outcome measured was success rate, pain relief and secondary outcome measured was QOL, recurrence and complication rate.

RESULTS

Ten studies with a sum of 11,154 individuals were included in this qualitative analysis. Seven studies compared MVD whereas 4 studies compared Gamma knife radiosurgery with other techniques like percutaneous balloon compression, percutaneous glycerol rhizotomy etc. The result showed that MVD has a considerable higher rate of initial pain-free outcomes (96.6%) followed by Gamma knife radiosurgery (96.2%), cryotherapy (95.4%), percutaneous balloon compression (87%), percutaneous glycerol rhizotomy (85%) and the lowest rate of cohorts who were never pain-free (1.7%).QOL was improved to 100% as a result of pain relief which was evaluated in only 2 studies . Overall the recurrence rate was 0.45 to 52%. MVD has lower rate of long-term recurrence 0.45 and 6.1% for 2 years and 8 years, respectively, and cryotherapy has the highest rate of 52% at 6 months.

CONCLUSION

Outcomes of the literature search showed that it lacks the knowledge to generally support 1 or the other treatment. Each type of TN requires individualized protocols to treat based on pain response which ultimately improve the QOL. We also propose there should be more reliable data reporting by using a universally acceptable pain scale for better analysis of treatment outcome.

Long-term pain outcomes in elderly patients with trigeminal neuralgia: comparison of first-time microvascular decompression and stereotactic radiosurgery

OBJECTIVE

Common surgical treatments for trigeminal neuralgia (TN) include microvascular decompression (MVD) and stereotactic radiosurgery (SRS). The use of MVD in elderly patients has been described but has yet to be prospectively compared to SRS, which is well-tolerated and noninvasive. The authors aimed to directly compare long-term pain control and adverse event rates for first-time surgical treatments for idiopathic TN in the elderly.

METHODS

A prospectively collected database was reviewed for TN patients who had undergone treatment between 1997 and 2017 at a single institution. Standardized collection of preoperative demographics, surgical procedure, and postoperative outcomes was performed. Data analysis was limited to patients over the age of 65 years who had undergone a first-time procedure for the treatment of idiopathic TN with at least 1 year of follow-up.

RESULTS

One hundred ninety-three patients meeting the study inclusion criteria underwent surgical procedures for TN during the study period (54 MVD, 24 MVD+Rhiz, 115 SRS). In patients in whom an artery was not compressing the trigeminal nerve during MVD, a partial sensory rhizotomy (MVD+Rhiz) was performed. Patients in the SRS cohort were older than those in the MVD and MVD+Rhiz cohorts (mean ± SD, 79.2 ± 7.8 vs 72.9 ± 5.7 and 70.9 ± 4.8 years, respectively; p < 0.0001) and had a higher mean Charlson Comorbidity Index (3.8 ± 1.1 vs 3.0 ± 0.9 and 2.9 ± 1.0, respectively; p < 0.0001). Immediate or short-term postoperative pain-free rates (Barrow Neurological Institute [BNI] pain intensity score I) were 98.1% for MVD, 95.8% for MVD+Rhiz, and 78.3% for SRS (p = 0.0008). At the last follow-up, 72.2% of MVD patients had a favorable outcome (BNI score I-IIIa) compared to 54.2% and 49.6% of MVD+Rhiz and SRS patients, respectively (p = 0.02). In total, 0 (0%) SRS, 5 (9.3%) MVD, and 1 (4.2%) MVD+Rhiz patients developed any adverse event. Multivariate Cox proportional hazards analysis demonstrated that procedure type (p = 0.001) and postprocedure sensory change (p = 0.003) were statistically significantly associated with pain control.

CONCLUSIONS

In this study cohort, patients who had undergone MVD had a statistically significantly longer duration of pain freedom than those who had undergone MVD+Rhiz or SRS as their first procedure. Fewer adverse events were seen after SRS, though the MVD-associated complication rate was comparable to published rates in younger patients. Overall, the results suggest that both MVD and SRS are effective options for the elderly, despite their advanced age. Treatment choice can be tailored to a patient's unique condition and wishes.

Microvascular Decompression for Trigeminal Neuralgia in Patients with Multiple Sclerosis: Predictors of Treatment Success

BACKGROUND

Microvascular decompression (MVD) is highly effective in managing the neuropathic facial pain of trigeminal neuralgia (TN). Its utility in patients with TN and concurrent multiple sclerosis (MS) has been a subject of debate. The goal of this study was to identify demographic and perioperative variables associated with favorable outcome after MVD over the past 20 years in patients from our institution.

METHODS

A retrospective analysis of our cohort of 33 patients diagnosed with MS and TN who underwent MVD between 1997 and 2017 to treat neuropathic facial pain was performed. Perioperative variables included MS disease burden, findings on preoperative magnetic resonance imaging (MRI), TN pain severity, and the presence of intraoperative neurovascular compression. MS disease burden was quantified using the Expanded Disability Status Scale. Preoperative and postoperative pain severity was quantified using the Barrow Neurological Institute (BNI) pain severity scale.

RESULTS

A total of 33 patients with TN and MS were treated with MVD at our institution (out of the 632 total MVDs performed) between 1997 and 2017. Twenty-two patients (67%) maintained a reduction in pain at a mean follow-up of 53.5 months. Higher preoperative BNI pain intensity score was associated with unfavorable outcome after MVD (P = 0.006). No associations were identified between MS disease burden, presence of neurovascular compression or pontine demyelinating plaques on MRI, or intraoperative findings of neurovascular compression and treatment outcomes.

CONCLUSIONS

MVD is a reasonable treatment option for patients with TN and MS, although the rate of freedom from pain is lower than that for the general TN population. Preoperative pain severity may be a predictor of treatment success.

One Hundred Eleven Percutaneous Balloon Compressions for Trigeminal Neuralgia in a Cohort of 66 Patients with Multiple Sclerosis

BACKGROUND

Trigeminal neuralgia associated with multiple sclerosis (MS-TN) is comparatively rare and larger series of percutaneous balloon compression (PBC) in such cases are few in the literature.

OBJECTIVE

To evaluate the results after PBC for MS-TN with regards to therapeutic effect, side effects, and complications.

METHODS

One hundred eleven procedures with PBC performed in 66 cases of MS-TN were analyzed. Therapeutic effect was measured as postoperative time to pain recurrence without medication. All complications were compiled and the sensory function was evaluated in a subgroup of cases.

RESULTS

The initial pain free rate was 67% and the median time to pain recurrence was 8 mo. Thirty-six patients were treated with PBC only, and among them, the results were worse if treated 3 to 4 times before, compared to first treatment (P = .009-.034). Patients who had several PBCs had worse results already after the first surgery (P < .001). A significant number of patients had impaired sensation to light touch directly after surgery, which was normalized at the late follow-up. Sensimetric testing showed raised thresholds for perception and pain directly after surgery (P = .004-.03), but these were also normalized at the late follow-up.

CONCLUSION

PBC is a treatment that can be effective for many patients with MS-TN. Repeated previous surgeries is a risk factor for an unsatisfactory outcome. However, the patients with multiple surgeries had less satisfactory results already at the first procedure, indicating that a therapy resistant disease can be predicted after the first two PBCs. Postoperative sensory deficits were common but not lasting.

Long-term pain outcomes for recurrent idiopathic trigeminal neuralgia after stereotactic radiosurgery: a prospective comparison of first-time microvascular decompression and repeat stereotactic radiosurgery

OBJECTIVE

Microvascular decompression (MVD) and stereotactic radiosurgery (SRS) are common surgical treatments for trigeminal neuralgia (TN). Many patients who receive SRS have pain recurrence; the ideal second intervention is unknown. The authors directly compared pain outcomes after MVD and repeat SRS in a population of patients in whom SRS failed as their first-line procedure for TN, and they identified predictors of pain control.

METHODS

The authors reviewed a prospectively collected database of patients undergoing surgery for TN between 1997 and 2014 at the University of California, San Francisco (UCSF). Standardized data collection focused on preoperative clinical characteristics, surgical characteristics, and postoperative outcomes. Patients with typical type 1, idiopathic TN with ≥ 1 year of follow-up were included.

RESULTS

In total, 168 patients underwent SRS as their first procedure. Of these patients, 90 had residual or recurrent pain. Thirty of these patients underwent a second procedure at UCSF and had ≥ 1 year of follow-up; 15 underwent first-time MVD and 15 underwent repeat SRS. Patients undergoing MVD were younger than those receiving repeat SRS and were more likely to receive ≥ 80 Gy during the initial SRS. The average follow-up was 44.9 ± 33.6 months for MVD and 48.3 ± 45.3 months for SRS. All patients achieved complete pain freedom without medication at some point during their follow-up. At last follow-up, 80% of MVD-treated patients and 33.3% of SRS-treated patients had a favorable outcome, defined as Barrow Neurological Institute Pain Intensity scores of I-IIIa (p < 0.05). Percentages of patients with favorable outcome at 1 and 5 years were 86% and 75% for the MVD cohort and 73% and 27% for the SRS cohort, respectively (p < 0.05). Multivariate Cox proportional hazards analysis demonstrated that performing MVD was statistically significantly associated with favorable outcome (HR 0.12, 95% CI 0.02-0.60, p < 0.01). There were no statistically significant predictors of favorable outcome in the MVD cohort; however, the presence of sensory changes after repeat SRS was associated with pain relief (p < 0.01).

CONCLUSIONS

Patients who received MVD after failed SRS had a longer duration of favorable outcome compared to those who received repeat SRS; however, both modalities are safe and effective. The presence of post-SRS sensory changes was predictive of a favorable pain outcome in the SRS cohort.

Immediate and Long-Term Outcomes of Microvascular Decompression for Mixed Trigeminal Neuralgia

BACKGROUND

Classic trigeminal neuralgia (TN) involves sharp, shooting pain in any trigeminal nerve distribution, whereas atypical TN presents with constant aching, numbness, or burning that can appear with classic features, leading to a mixed presentation. Microvascular decompression (MVD) is an effective treatment for classic TN, but its utility in treating mixed TN has been less well studied.

METHODS

We retrospectively studied 73 adult patients with mixed TN and 386 patients with classic TN who underwent MVD between December 2007 and October 2016. Recorded variables included demographic data, graded radiologic and intraoperative findings, and graded pain outcomes in the immediate postoperative period (up to 3 months after MVD) and during long-term follow-up.

RESULTS

The mean age of the 73 patients with mixed TN was 53.2 years. In terms of immediate postoperative outcomes, 67 patients (91.8%) experienced pain relief including improvement of atypical pain, whereas 6 patients (8.2%) had no pain relief. Having a preexisting pain syndrome (P = 0.001) or distortion of the trigeminal nerve intraoperatively (P = 0.001) was associated with poor surgical outcome in the patients with mixed TN. The mean duration of follow-up was 20.6 months. Forty-four patients (60.3%) developed recurrence of any TN pain. In comparison, 93% of the patients with classic TN experienced pain relief in the immediate postoperative period, and the recurrence rate was 19.9% in these patients.

CONCLUSIONS

Patients with mixed TN suffer from both classic and atypical TN symptoms. Following MVD, 91.8% of our patients with mixed TN reported partial or complete pain relief, including improvement of atypical pain, in the immediate postoperative stage, compared with 93% of those with classic TN. Recurrence eventually developed in 60.3% of the patients with mixed TN.

Prospective comparison of long-term pain relief rates after first-time microvascular decompression and stereotactic radiosurgery for trigeminal neuralgia

OBJECTIVE

Common surgical treatments for trigeminal neuralgia (TN) include microvascular decompression (MVD), stereotactic radiosurgery (SRS), and radiofrequency ablation (RFA). Although the efficacy of each procedure has been described, few studies have directly compared these treatment modalities on pain control for TN. Using a large prospective longitudinal database, the authors aimed to 1) directly compare long-term pain control rates for first-time surgical treatments for idiopathic TN, and 2) identify predictors of pain control.

METHODS

The authors reviewed a prospectively collected database for all patients who underwent treatment for TN between 1997 and 2014 at the University of California, San Francisco. Standardized collection of data on preoperative clinical characteristics, surgical procedure, and postoperative outcomes was performed. Data analyses were limited to those patients who received a first-time procedure for treatment of idiopathic TN with > 1 year of follow-up.

RESULTS

Of 764 surgical procedures performed at the University of California, San Francisco, for TN (364 SRS, 316 MVD, and 84 RFA), 340 patients underwent first-time treatment for idiopathic TN (164 MVD, 168 SRS, and 8 RFA) and had > 1 year of follow-up. The analysis was restricted to patients who underwent MVD or SRS. Patients who received MVD were younger than those who underwent SRS (median age 63 vs 72 years, respectively; p < 0.001). The mean follow-up was 59 ± 35 months for MVD and 59 ± 45 months for SRS. Approximately 38% of patients who underwent MVD or SRS had > 5 years of follow-up (60 of 164 and 64 of 168 patients, respectively). Immediate or short-term (< 3 months) postoperative pain-free rates (Barrow Neurological Institute Pain Intensity score of I) were 96% for MVD and 75% for SRS. Percentages of patients with Barrow Neurological Institute Pain Intensity score of I at 1, 5, and 10 years after MVD were 83%, 61%, and 44%, and the corresponding percentages after SRS were 71%, 47%, and 27%, respectively. The median time to pain recurrence was 94 months (25th–75th quartiles: 57–131 months) for MVD and 53 months (25th–75th quartiles: 37–69 months) for SRS (p = 0.006). A subset of patients who had MVD also underwent partial sensory rhizotomy, usually in the setting of insignificant vascular compression. Compared with MVD alone, those who underwent MVD plus partial sensory rhizotomy had shorter pain-free intervals (median 45 months vs no median reached; p = 0.022). Multivariable regression demonstrated that shorter preoperative symptom duration (HR 1.005, 95% CI 1.001–1.008; p = 0.006) was associated with favorable outcome for MVD and that post-SRS sensory changes (HR 0.392, 95% CI 0.213–0.723; p = 0.003) were associated with favorable outcome for SRS.

CONCLUSIONS

In this longitudinal study, patients who received MVD had longer pain-free intervals compared with those who underwent SRS. For patients who received SRS, postoperative sensory change was predictive of favorable outcome. However, surgical decision making depends upon many factors. This information can help physicians counsel patients with idiopathic TN on treatment selection.

Puncture of Cerebellar Horizontal Fissure for Retrosigmoid Approach: A Prospective and Quantitative Analysis

BACKGROUND

Cerebrospinal fluid (CSF) drainage is important in retrosigmoid approached surgery; however, in some cases, it is not feasible due to cerebellar swelling.

OBJECTIVE

To introduce a method, puncture of the horizontal fissure of the cerebellum, which can reduce the cerebellum to easily obtain a good operative corridor and slowly drain CSF.

METHODS

Between January and December 2014, we estimated the precise location of the horizontal fissure in 56 patients who underwent surgery via a retrosigmoid approach. Then, we collected and analyzed CSF drained by puncturing the horizontal fissure. We investigated whether a good operative corridor was obtained with this method.

RESULTS

The location of the precise horizontal fissure was a mean of 3.97 mm caudal to transverse sinus and the mean amount of CSF drained in 56 patients was 50.4 mL. A good corridor was obtained in 46 (82.1%) of 56 patients without additional cistern puncture.

CONCLUSION

The puncture of the horizontal fissure can be useful in retrosigmoid approach surgery. Moreover, inexperienced surgeons can use this method to effectively avoid injury of the cerebellum.

Suprafloccular approach via the petrosal fissure and venous corridors for microvascular decompression of the trigeminal nerve: technique notes and clinical outcomes

OBJECTIVE Surgical exposure and decompression of the entire trigeminal nerve in a conventional lateral supracerebellar approach can be challenging because of blockages from the superior petrosal vein complex, cerebellum, and vestibulocochlear nerve. The authors demonstrate a novel suprafloccular approach via the petrosal fissure and venous corridors that can be used as a substitute for the conventional route used to treat trigeminal neuralgia and present a consecutive series of patients and their clinical outcomes. METHODS Preoperative and postoperative clinical data from 420 patients who underwent this modified approach at Hangzhou First People's Hospital between March 2012 and May 2014 were reviewed. The technique expands the working space by opening the petrosal fissure and dissecting adhesions between the vein of the cerebellopontine fissure and the simple lobule as needed. Via 3 surgical corridors, the entire trigeminal nerve is exposed and decompressed thoroughly with minimal retraction of the surrounding vital structures. RESULTS The medial one-third of the trigeminal nerve accounted for the majority (275 [65.5%] cases) of neurovascular conflict sites. The lateral corridor was used in 219 (52.1%) cases, the medial corridor was used in 175 (41.7%) cases, and the intermediate corridor was used in 26 (6.2%) cases. The entire trigeminal nerve in each patient was accessed directly and decompressed properly. At the end of the 24-month follow-up period, the rate of excellent results (Kondo score of T0 or T1) was stable at approximately 90.5%. No complications were related directly to petrosal vein or vestibulocochlear nerve injury. CONCLUSIONS Based on data from the large patient series, the authors found this suprafloccular approach via the petrosal fissure and venous corridors provides full exposure and decompression of the entire trigeminal nerve, a high cure rate, and a low neurovascular morbidity rate.

The Current Status of Microvascular Decompression for the Treatment of Hemifacial Spasm in Japan: An Analysis of 2907 Patients Using the Japanese Diagnosis Procedure Combination Database

Microvascular decompression (MVD) is widely used as a safe and effective treatment for hemifacial spasm (HFS). However, the extent of application of this therapeutic method and its outcomes in Japan are currently unclear. To address these questions, we analyzed the utilization of MVD for the treatment of HFS during the 33- month period from July 2010 to March 2013. We conducted an analysis on data contained in the Diagnosis Procedure Combination database in Japan. This analysis showed that MVD was used for the treatment of HFS in 2907 cases (men, 916; women, 1991) with 2.2 times more women treated than men. MVD for HFS was most frequently performed in women aged 50 to 69 years; however, most men were aged between 40 and 59 years at the time of the procedure. The numbers of procedures performed per 100,000 population/year were 0.83 overall in Japan, with the numbers larger in prefectures with larger populations. Regarding discharge outcomes, the mortality rate was 0.1%. The mean length of hospital stay in patients undergoing MVD for HFS was 14.7 days. This analysis provides preliminary information regarding the trends in the performance of MVD for the treatment of HFS in Japan. Further studies on other registries that contain data obtained by standardized assessment methods and that include long-term outcomes and postoperative complications are required.

Options in treating trigeminal neuralgia: Experience with 195 patients

OBJECTIVE

For patients with medically unresponsive trigeminal neuralgia (TN), surgical options include microvascular decompression (MVD), radiofrequency rhizotomy (RF), and stereotactic radiosurgery (SRS). In an attempt to identify the risks and benefits and cost inherent with each of the three modalities, we performed a retrospective review of our experience with 195 cases of TN treated over the past 15 years.

METHODS

Since 2001, 195 patients with previously untreated TN were managed: with MVD in 79, RF in 36, and SRS in 80. All patients reported herein underwent preoperative MRI. Women outnumbered men 122/73 (p=0.045). Follow-up after surgery was 32±46months.

RESULTS

The patients qualifying for MVD were generally healthier and younger, with a mean age±SD of 57±14, compared to those undergoing RF (75±15) or SRS (73±13, p<0.0001). In case of relapse, medical treatment was always tried and failed prior to consideration of surgical intervention. A second surgical procedure was necessary in 2, 23, and 18 patients initially treated with MVD, RF, and SRS respectively (p<0.0001). In the patients treated with MVD, RF, and SRS, the average number of procedures per patient necessary to achieve pain control was 1.1, 2.0, and 1.3 respectively (p=0.001). There were 7 complications in the patients treated with MVD but no deaths. Numbness was present in 13, 18, and 29 patients treated with MVD, RF, and SRS respectively (p=0.008).

CONCLUSION

MVD for TN is the treatment least likely to fail or require additional treatment. Patients who underwent MVD were younger than those undergoing RF or SRS. The highest rate of recurrence of TN was encountered in patients undergoing RF (64%). Facial numbness was least likely to occur with MVD (16%) compared to RF and SRS (50% and 36% respectively).

A Perforating Artery Compressing the Nerve Rootlet and Causing Glossopharyngeal Neuralgia

BACKGROUND

A surgical procedure for glossopharyngeal neuralgia (GPN) was selected from microvascular decompression, glossopharyngeal and upper vagal rhizotomy, or a combination of these procedures based on the presence of arteries compressing the glossopharyngeal and vagal rootlets. The offending artery is usually a main trunk or branch of the cerebellar arteries. A perforating artery is a known but uncommon variation of the offending artery that causes GPN. The appropriate procedure for such cases is unknown.

OBJECTIVE

To analyze the clinical significance of the perforating artery in GPN, we describe 2 patients with a perforating artery compressing the rootlet, and its mobilization relieved neuralgia. We examined the validity of decompressing a perforating artery as an alternative to rhizotomy in such cases.

METHODS

We independently reviewed 12 GPN patients treated with microvascular decompression. The patients' pain severity, medication doses, preoperative imaging studies, intraoperative findings, and outcomes were examined.

RESULTS

Eleven patients had neurovascular compression of the glossopharyngeal nerve. In 2 of the patients, a perforating artery compressed the rootlet, thereby generating an indentation and creating a discoloration of the rootlet. Mobilizing the perforating artery with no additional rhizotomy provided complete pain relief with no significant complications and allowed the discontinuation of medications.

CONCLUSION

Even a small perforating artery can cause GPN when it compresses the rootlet. In such cases, mobilization of the perforating artery with no additional rhizotomy is an effective surgical option.

Analysis of therapeutic effect of microvascular decompression surgery on idiopathic hemifacial spasm

OBJECTIVE

The objective of this paper is to study the therapeutic effect of microvascular decompression surgery on idiopathic hemifacial spasm with compression on different zones of facial nerve.

METHODS

The clinical data of 348 patients with idiopathic hemifacial spasm treated by microvascular decompression surgery were retrospectively analyzed. Patients were divided into 5 groups according to compression on different zones of facial nerve by offending vessels. Root exit point was compressed in 18 patients (group A), transitional zone of brainstem was compressed in 42 patients (group B), attached segment of brainstem was compressed in 35 patients (group C), distal cisternal portion was compressed in 21 patients (group D), and 2 or more zones were compressed in 232 patients (group E). The therapeutic effect was observed, and outcome of excellent and partial good were regarded as effective.

RESULTS

Patients were followed up for 0.5 to 2 years. The effective rates were 94.4%, 95.2%, 97.1%, 95.2%, and 93.9% in group A, group B, group C, group D, and group E, respectively.No death occurred during operation,and there were no severe complications such as complete facial paralysis, intracranial hematoma, and hearing loss after operation.

CONCLUSION

Microvascular decompression surgery is the first choice for treatment hemifacial spasm. Proper detection of offending vessels and complete decompression may be the key factors to increase the cure rate.