Endoscopic versus microscopic microvascular decompression for trigeminal neuralgia: equivalent pain outcomes with possibly decreased postoperative headache after endoscopic surgery

Pain Outcomes Following Endoscopic Microvascular Decompression for Trigeminal Neuralgia Based on Vascular Compression Type

Background  Arterial compression of the trigeminal nerve at the root entry zone has been the long-attributed cause of compressive trigeminal neuralgia despite numerous studies reporting distal and/or venous compression. The impact of compression type on patient outcomes has not been fully elucidated. Objective  We categorized vascular compression (VC) based on vessel and location of compression to correlate pain outcomes based on compression type. Methods  A retrospective video review of 217 patients undergoing endoscopic microvascular decompression for trigeminal neuralgia categorizing VC into five distinct types, proximal arterial compression (VC1), proximal venous compression (VC2), distal arterial compression (VC3), distal venous compression (VC4), and no VC (VC5). VC type was correlated with postoperative pain outcomes at 1 month ( n  = 179) and last follow-up (mean = 42.9 mo, n  = 134). Results  At 1 month and longest follow-up, respectively, pain was rated as "much improved" or "very much improved" in 89 69% of patients with VC1, 86.6 and 62.5% of patients with VC2, 100 and 87.5% of patients with VC3, 83 and 62.5% of patients with VC4, and 100 and 100% of patients with VC5. Multivariate analysis demonstrated VC4 as a significant negative of predictor pain outcomes at 1 month, but not longest follow-up, and advanced age as a significant positive predictor. Conclusion  The degree of clinical improvement in all types of VC was excellent, but at longest follow-up VC type was not a significant predictor out outcome. However distal venous compression was significantly associated with worse outcomes at 1 month.

Fully Endoscopic Microvascular Decompression for Trigeminal Neuralgia Caused by Vertebrobasilar Artery: A Case Series Review: 2-Dimensional Operative Video

BACKGROUND AND OBJECTIVE

Microvascular decompression (MVD) is the most definitive and preferred surgical treatment for trigeminal neuralgia (TN). Treatment of TN caused by the vertebrobasilar artery (VBA) has been reported to be challenging and less satisfactory in complications and recurrence. Endoscopy has been implemented to provide a comprehensive view of neurovascular conflicts and minimize brain tissue stretch injury while exploring the trigeminal nerve. However, there are few retrospective studies on the treatment of TN caused by VBA by fully endoscopic microvascular decompression (E-MVD). This article aimed to illustrate the safety and efficacy of E-MVD for TN caused by the VBA.

METHODS

Clinical data for 26 patients with TN caused by the VBA who underwent E-MVD from 2019 to 2022 were retrospectively analyzed. The characteristics of vertebrobasilar-associated TN were summarized. The safety and efficacy of E-MVD for vertebrobasilar-associated TN were estimated based on the analysis of intraoperative manipulation, postoperative symptom relief, and complications.

RESULTS

Intraoperatively, the vertebrobasilar artery was regarded as a direct offending vessel in all 26 patients with TN, the vertebral artery in 18 (69.23%) and the basilar artery in 10 (38.46%). In addition to the vertebrobasilar artery, other vessels involved included the superior cerebellar artery in 12 patients, anterior inferior cerebellar artery in 9, posterior inferior cerebellar artery in 1, and veins in 4. All patients underwent E-MVD, and TN was entirely resolved in 26 (100%) patients immediately postoperatively. During the follow-up period of 12-45 months, no recurrence or serious complications were found. There were no serious postoperative complications, such as cerebellar swelling, intracranial hemorrhage, or death.

CONCLUSION

E-MVD for vertebrobasilar-associated TN is effective and safe.

Daily olive oil intake is feasible to reduce trigeminal neuralgia facial pain: A pilot study

Extra virgin olive oil (EVOO) is thought to contribute to neuroprotection and, thus, may influence pain symptoms experienced by adults with demyelination-related trigeminal neuralgia (TN). This study aimed to determine the feasibility of daily intake of EVOO and its potential to alleviate facial pain of TN. Adults, self-reporting as female and affected by TN, were enrolled in a 16-week nonblinded, parallel study. After a 4-week baseline, participants were randomized to 60 mL/day EVOO or control (usual diet and no supplemental EVOO) for 12 weeks. Participants completed a daily questionnaire on pain intensity and compliance, the Penn Facial Pain Scale weekly, the 36-Item Short Form Survey monthly, and dietary assessment during baseline and intervention. Participants (n = 52; 53.3 ± 12.9 years) were recruited nationally; 42 completed the study. The EVOO group, with 90% intake compliance, showed significant decreases in the Penn Facial Pain Scale items of interference with general function, interference with orofacial function, and severity of pain from baseline, whereas the control group showed no improvements. EVOO benefit, compared with control, trended for the interference with orofacial function (P = .05). The 36-Item Short Form Survey items of role limitations resulting from emotional problems and role limitations from physical health favored EVOO. The EVOO group significantly improved their Healthy Eating Index 2015 component scores of fatty acids (primarily from increased oleic acid), sodium, and refined grains. EVOO intake of 60 mL/day was feasible for participants experiencing TN and may mitigate pain and improve quality of life. This trial was registered at clinicaltrials.gov (NCT05032573).

Endoscopic Microvascular Decompression

Microvascular decompression is a widely accepted surgical treatment for compressive cranial nerve pathologies such as trigeminal neuralgia, hemifacial spasm, glossopharyngeal neuralgia, and other craniofacial pain syndromes. Endoscopy has risen as a safe and effective minimally invasive tool to optimize microvascular decompression. Endoscopy offers improved visualization, minimizes retraction, and allows for smaller surgical openings compared to traditional microscopic approaches. There are several reports of improved neuralgia outcomes and reduced post-operative complications after endoscopic microvascular decompression. In skilled surgical hands, endoscopy is an excellent option for microvascular decompression as stand-alone tool or adjunct to the microscope. An overview of the history, operative considerations, and techniques is provided in this chapter.

Endoscopic microvascular decompression versus microscopic microvascular decompression for trigeminal neuralgia: A systematic review and meta-analysis

BACKGROUND

To compare the efficacy and safety of full endoscopic or endoscope-assisted microvascular decompression (E-MVD) and microscopic microvascular decompression (M-MVD) for primary trigeminal neuralgia (TN).

METHODS

We systematically searched the online database, including PubMed, Embase and Cochrane Library. The search terms used included, but were not limited to, "Trigeminal Neuralgia", "Microvascular Decompression Surgery" and "Endoscope". Postoperative facial pain relief and postoperative complications were considered for meta-analysis. All the outcomes were calculated as odds ratios (ORs) with 95% confidence intervals using R language.

RESULTS

A total of three studies involving 442 (E-MVD [218] versus M-MVD [224]) patients were included for analysis in our study. Postoperative facial pain relief (very much improved or much improved) was no difference between the two groups (OR, 0.95;95% CI, 0.57-1.58; I2 = 0%; p = 0.83). In addition, the occurrence of some postoperative complications was not statistically different between the two groups, including CSFleak (OR, 1.35;95% CI, 0.16-11.13; I2 = 0%; p = 0.94), facial paralysis (OR, 0.26;95% CI, 0.03-2.54; I2 = 0%; p = 0.67), hearing loss (OR, 0.87;95% CI, 0.30-2.55; I2 = 32%; p = 0.22), facial numbness (OR, 1.03;95% CI, 0.56-1.87; I2 = 62%; p = 0.10).

CONCLUSIONS

Both endoscopic microvascular decompression and microscopic microvascular decompression for trigeminal neuralgia appear to provide patients with equivalent facial pain relief outcomes. Complication rates were also similar between the groups.

Fully endoscopic microvascular decompression for the treatment of hemifacial spasm, trigeminal neuralgia, and glossopharyngeal neuralgia: a retrospective study

BACKGROUND

Microvascular decompression (MVD) is already the preferred surgical treatment for medically refractory neurovascular compression syndromes (NVC) such as hemifacial spasm (HFS), trigeminal neuralgia (TN), and glossopharyngeal neuralgia (GPN). Endoscopy has significantly advanced surgery and provides enhanced visualization of MVD. The aim of this study is to analyze the efficacy and safety of fully endoscopic microvascular decompression (E-MVD) for the treatment of HFS, TN, and GPN, as well as to present our initial experience.

MATERIALS AND METHODS

This retrospective case series investigated fully E-MVD performed in 248 patients (123 patients with HFS, 115 patients with TN, and 10 patients with GPN ) from December 2008 to October 2021 at a single institution. The operation duration, clinical outcomes, responsible vessels, intra- and postoperative complications, and recurrences were recorded. Preoperative and immediate postoperative magnetic resonance imaging (MRI) and computerized tomography (CT) were performed for imageological evaluation. The Shorr grading and Barrow Neurological Institute (BNI) pain score were used to evaluate clinical outcomes. The efficacy, safety, and risk factors related to the recurrence of the operation were retrospectively analysed, and the surgical techniques of fully E-MVD were summarised.

RESULTS

A total of 248 patients (103 males) met the inclusion criteria and underwent fully E-MVD were retrospectively studied. The effective rate of 123 patients with HFS was 99.1%, of which 113 cases were completely relieved and 9 cases were significantly relieved. The effective rate of 115 patients with TN was 98.9%, of which 105 cases had completely pain relieved after surgery, 5 cases had significant pain relieved, 4 cases had partial pain relieved but still needed to be controlled by medication. The effective rate of 10 patients with GPN was 100%, 10 cases of GPN were completely relieved after surgery. As for complications, temporary facial numbness occurred in 4 cases, temporary hearing loss in 5 cases, dizziness with frequent nausea and vomiting in 8 cases, headache in 12 cases, and no cerebral hemorrhage, intracranial infection, and other complications occurred. Follow-up ranged from 3 to 42 months, with a mean of 18.6 ± 3.3 months. There were 4 cases of recurrence of HFS and 11 cases of recurrence of TN. The other effective patients had no recurrence or worsening of postoperative symptoms. The cerebellopontine angle (CPA) area ratio (healthy/affected side), the length of disease duration, and the type of responsible vessels are the risk factors related to the recurrence of HFS, TN, and GPN treated by fully E-MVD.

CONCLUSIONS

In this retrospective study, our results suggest that the fully E-MVD for the treatment of NVC such as HFS, TN, and GPN, is a safe and effective surgical method. Fully E-MVD for the treatment of NVC has advantages and techniques not available with microscopic MVD, which may reduce the incidence of surgical complications while improving the curative effect and reducing the recurrence rate.

Questionnaire for Dental Practitioners to Screen for Trigeminal Neuralgia

Objective  Trigeminal neuralgia (TN) is a neurological disorder that often presents as severe toothache. The majority of TN patients visit dental clinics first, so TN represents a potential pitfall for dental practitioners. This report describes the development of a trigeminal neuralgia questionnaire (TNQ), assessing 10 characteristics of TN, to assist dentists in screening for TN in dental clinics, and evaluates the effectiveness of TNQ. Materials and Methods  Fifty-three patients who visited the TN outpatient department in our institute and completed the TNQ were included in this study. All patients were examined by two neurosurgeons and neuroimaging was performed. Statistical Analysis  Patients were classified into a TN group and a non-TN group. TNQ score was retrospectively compared between groups. Furthermore, history and characteristics of TN were investigated in the TN group to clarify the status of the reference situation. Results  Thirty-seven cases were assigned to the TN group, and 16 cases to the non-TN group. Mean TNQ score was 8.3 in the TN group and 6.6 in the non-TN group. Setting a TNQ cutoff score of 7 offered 91% sensitivity and 56% specificity for TN. Investigation of the history of the present illness indicated that 39.2% of TN cases were improperly triaged and referred from initial dental clinics, and interdisciplinary practice was insufficient. Conclusion  TNQ offers a reliable, convenient method to triage TN patients, and may assist dentists in screening for TN. Multidisciplinary practice is necessary for total management of TN and the TNQ is expected to connect dentists and TN specialists.

Preservation of Enlarged Mastoid Emissary Vein during Microvascular Decompression for Trigeminal Neuralgia Accompanied by Abnormal Venous Drainage: A Technical Case Report

During microvascular decompression (MVD) for trigeminal neuralgia (TGN), the mastoid emissary veins (MEV) are routinely sacrificed using the suboccipital retrosigmoid approach. The technical nuances when the MEV is an important collateral venous pathway for the obstructive internal jugular vein (IJV) have not been described thus far. Herein, we demonstrate for the first time a modified surgical technique for MVD to preserve the MEV. A 62-year-old man with a 10-year history of TGN refractory to carbamazepine was referred to our hospital for MVD. Preoperative imaging revealed that the superior cerebellar artery was the offending vessel. Computed tomography angiography also revealed that his contralateral IJV pathway was hypoplastic, and the ipsilateral pathway was severely stenosed by the external compression of the elongated styloid process and the transverse process of the first cervical vertebra. The ipsilateral MEV and the connecting occipital veins were enlarged as the sole collateral pathways of intracranial venous drainage. A modified MVD technique, including an upside-down L-shaped skin incision, layer-by-layer dissection of the occipital muscles, and denuding of the intraosseous part of the MEV, was used to cure the TGN with the preservation of the venous pathway. After surgery, the pain completely diminished without any complications. In conclusion, such technical modifications would be applicable in cases where the MEV needs to be preserved during posterior fossa surgery. Preoperative screening of the venous system is also recommended.

Case report: Fully endoscopic microvascular decompression for trigeminal neuralgia

Microvascular decompression is safe, effective, and micro-invasive. Due to these advantages, it has become the mainstream treatment for trigeminal neuralgia, glossopharyngeal neuralgia, and hemifacial spasm. Initially, microvascular decompression was performed under a microscope, which limited the light source and visualization capabilities. With the development of endoscopic technology, the endoscope has been used in microvascular decompression, which further improved the visualization range and light source properties. The purpose of the present study was to investigate the efficacy of fully endoscopic microvascular decompression for the treatment of trigeminal neuralgia. In total, three patients with trigeminal neuralgia who underwent fully endoscopic microvascular decompression were evaluated. After surgery, the facial pain of all patients was significantly relieved. In addition, there were no obvious postoperative complications and no recurrence after 6 months of follow-up. These excellent surgical outcomes indicate that fully endoscopic microvascular decompression is an effective and safe method for the treatment of trigeminal neuralgia. Furthermore, it also shows that the endoscope presents advantages for use in microvascular decompression.

Microvascular decompression: Diversified of imaging uses, advantages of treating trigeminal neuralgia and improvement after the application of endoscopic technology

Classical trigeminal neuralgia (CTN) is a unilateral and severe facial pain disease, which seriously affects the patient's quality of life. Microvascular decompression (MVD) is currently the most effective surgical method, and it is the only treatment for the etiology of CTN. Imaging for MVD has been increasingly used, and the advantages and disadvantages of endoscopy-assisted vascular decompression surgery have been controversially debated. In this review, we aimed to discuss the advantages of MVD in the treatment of patients with CTN, the importance of using imaging in disease management, and the improvements of vascular decompression surgery through the application and maturity of endoscopic techniques. Compared with other surgical methods, MVD has more prominent short- and long-term treatment effects. Its selection depends on the accurate discovery of neurovascular compression by preoperative imaging. Moreover, magnetic resonance imaging plays a diverse role in MVD, not only in identifying the responsible vessels but also in determining the prognosis and as a tool for scientific research. The use of endoscopic techniques provides improved visualization of the MVD and additional benefits for vascular decompression surgery.

Epidemiology of post-suboccipital craniotomy headache: A multicentre retrospective study

The detailed epidemiology and mechanism of post-craniotomy headaches are not well understood. This study aimed to establish the actual clinical incidence and causes of post-craniotomy headaches. Suboccipital craniotomy surgeries performed in six institutions within the five-year study period were included. This study included 311 patients (138 males, 173 female; mean age, 59.3 years old). A total of 145 patients (49%) experienced post-craniotomy headaches. Microvascular decompression surgery, craniectomy and facial spasms were significant risk factors for post-craniotomy headaches. In most cases, the post-craniotomy headaches disappeared within one month; however, some patients suffered from long-term headaches. The craniotomy site and the methods of dura and skull closures should be individually determined for each patient. However, to prevent post-craniotomy headaches, craniotomy, instead of craniectomy, may be considered.

Posterior fossa endoscopic-assisted surgery: A systematization of its surgical corridors

INTRODUCTION

The use of endoscopic-assisted techniques in neurosurgery has been implemented to improve better visualization and predict extent of resection. We aim to systematize the posterior fossa surgical regions and the endoscopic surgical corridors providing a quick reference of the anatomy and surgical nuances.

METHODS

A retrospective review of patients undergoing endoscopic-assisted surgery of the posterior fossa at a single institution between 2019 and 2020 was conducted along with a description of the microsurgical anatomy from cadaveric specimens and surgical cases.

RESULTS

The posterior fossa was segmented into three topographic regions, (upper, middle and lower), with three surgical corridors within each of these. Upper region is accessed through a supracerebellar infratentorial approach and comprises the pineal and pericuadrigeminal region constituted by the median corridor, the lateral corridor, and the extreme lateral corridor. Middle region is accessed through a retrosigmoid approach and comprises the cerebellopontine angle region constituted by the supralateral corridor containing the upper neurovascular complex (NVC), the median corridor containing the median NVC, and the infralateral corridor containing the lower NVC. The lower region is accessed through a far-lateral approach and contains the craniocervical junction region constituted by the upper corridor in between the VII-VIII and IX cranial nerves (CNs), the median corridor between the X and XI CNs, and the lower corridor between the cranial and spinal rootlets of the XI CN.

CONCLUSION

We propose a simple and concise systematization, dividing the area into three regions with predefined corridors.

Endoscopic Microvascular Decompression for Vagoglossopharyngeal Neuralgia

Glossopharyngeal neuralgia (GN) is a nerve compression syndrome that presents with episodes of unilateral sharp, stabbing pain in the distribution of the ninth cranial nerve. This syndrome may present with cardiac and autonomic manifestations - a condition termed vagoglossopharyngeal neuralgia (VGPN). Most cases of VGPN arise from neurovascular insult at the cerebellopontine angle. Conservative treatment for VGPN includes antiepileptic medications. Surgical treatments include trigeminal tractotomy-nucleotomy, Gamma Knife® stereotactic radiosurgery, radiofrequency thermocoagulation, rhizotomy, and, as shown in this paper, endoscopic microvascular decompression (E-MVD). In this article, we present two cases. Case 1 demonstrates a 53-year-old male with right-sided GN symptoms that began to experience syncopal episodes 10-years after the initial presentation. Case 2 presents a 61-year-old female with a history of Ehlers-Danlos syndrome, and the malignant vasovagal syndrome that became associated with painful, shooting left anterior neck spasms consistent with GN. Both patients underwent E-MVD, leading to complete relief of neuralgia and cardiac symptoms. Our outcomes support previously published reports of successful treatment of VGPN using microvascular decompression (MVD) and describe a purely endoscopic surgical technique. MVD is the preferred treatment option for VGPN with evident neurovascular insult.

Dexmedetomidine Combined With Butorphanol or Sufentanil for the Prevention of Post-operative Nausea and Vomiting in Patients Undergoing Microvascular Decompression: A Randomized Controlled Trial

Background: Patients undergoing microvascular decompression are often accompanied with high risk of post-operative nausea and vomiting (PONV). In this study, we compare the antiemetic efficacy of butorphanol or sufentanil combined with dexmedetomidine in patients undergoing microvascular decompression.

Methods: Patients undergoing microvascular decompression were randomized into two groups. The primary outcome was the occurrence and severity of PONV during the 72 h after surgery. Secondary outcomes included levels of pain intensity and sedation and consumption of opioids at 1, 2, 6, 12, 24, 48, and 72 h after surgery. We also recorded the intraoperative hemodynamics, consumption of narcotic drugs, operation and anesthesia time, estimated blood loss, infusion volume and urine output, requirements of rescue antiemetics or analgesics, the satisfaction scores of patients and surgeons, complications, and length of stay.

Results: The overall incidence rates of nausea and vomiting during the 72 h after surgery were significantly reduced in group DB (76.00 and 44.00% in group DS vs. 54.17% and 22.92% in group DB, P < 0.05). Patients in group DB had a lower incidence of nausea than those in group DS at intervals of 1–6 and 6–24 h (P < 0.05). However, patients in group DB had a lower incidence of vomiting than those in group DS only at intervals of 1–6 h (P < 0.05). Similarly, the number of patients requiring rescue antiemetics was also significantly reduced in group DB compared with that in group DS at intervals of 1–6 h (P < 0.05). The number of patients experiencing moderate to severe PONV was comparable between the two groups during 72 h after surgery (P > 0.05). The consumption of opioid morphine equivalent was significantly reduced in group DB (P < 0.05). Compared with those in group DS, the satisfaction scores of both patients and surgeons were significantly increased in group DB (P < 0.05).

Conclusion: Butorphanol combined with dexmedetomidine could reduce early PONV and the number of patients requiring rescue antiemetics, especially at intervals of 1–6 h, while the satisfaction scores of both patients and surgeons were significantly increased.

Endoscopic Vascular Decompression for the Treatment of Trigeminal Neuralgia: Clinical Outcomes and Technical Note

Purpose

Microvascular decompression (MVD) surgery is considered as an effective method with which to treat trigeminal neuralgia (TN). However, sometimes MVD surgery fails due to incomplete decompression of the responsible vessels caused by a poor visual field. In this study, we evaluated the benefits of endoscopic visualization and the value of full endoscopic vascular decompression (EVD) by describing the surgical results of 20 patients with TN after EVD.

Patients and Methods

This was a retrospective study in a single institution of 20 patients with TN who received EVD between April 2018 and October 2019. All patients underwent EVD via the suboccipital retrosigmoid approach without microscopy at any stage. Abnormal muscle response (AMR) and brainstem auditory evoked potentials (BAEPs) were routinely monitored throughout the procedure. Follow-up was conducted by outpatient and telephone interviews. The degree of facial pain was graded using the Barrow Neurological Institute (BNI) pain intensity score; a BNI of 1 was considered as the best result while a BNI of 2 or 3 was considered as a satisfactory result. Follow-up time ranged from 8 to 24 months, with a mean of 18±4.36 months.

Results

All 20 patients with severe preoperative pain (BNI of 5) achieved immediate relief or complete control of pain after surgery (BNI of 1 to 2). Vascular conflicts were observed during surgery in all of the patients. None of the patients experienced hearing loss, facial paralysis, intracranial infection, cerebrospinal fluid leakage, cerebral hemorrhage, or death, following the operation.

Conclusion

When carried out by surgeons with endoscopic experience, EVD can provide a clear surgical field of view and reduce the risk of surgical injury. Our findings indicate that EVD is a safe and effective surgical method for the treatment of TN.

Endoscopic versus open microvascular decompression for trigeminal neuralgia: a systematic review and comparative meta-analysis

OBJECTIVE

Microvascular decompression (MVD) is commonly used in the treatment of trigeminal neuralgia (TN) with positive clinical outcomes. Fully endoscopic MVD (E-MVD) has been proposed as an effective minimally invasive alternative, but a comparative review of the two approaches has not been conducted. The authors performed a meta-analysis of studies, comparing patient outcome rates and complications for the open versus the endoscopic technique.

METHODS

The PubMed/MEDLINE and Ovid databases were searched for studies published from database inception to 2017. The search terms used included, but were not limited to, "open microvascular decompression," "microvascular decompression for trigeminal neuralgia," and "endoscopic decompression for trigeminal neuralgia." Criteria for inclusion of studies in the meta-analysis were established as follows: adult patients, clinical studies with ≥ 10 patients (excluding case studies to obtain a higher volume of outcome rates), utilization of open MVD or E-MVD to treat TN, craniotomy and retrosigmoid incision, English-language studies, and articles that listed pain relief outcomes (complete, very good, partial, or absent), recurrence rate (number of patients), and complications (paresis, hearing loss, CSF leakage, cerebellar damage, infection, death). Relevant references from the chosen articles were also included.

RESULTS

From a larger pool of 1039 studies, 23 articles were selected for review: 13 on traditional MVD and 10 on E-MVD. The total number of patients was 6749, of which 5783 patients (and 5802 procedures) had undergone MVD and 993 patients (and procedures) had undergone E-MVD. Analyzed data included postoperative pain relief outcome (complete or good pain relief vs partial or no pain relief), and rates of recurrence and complications including facial paralysis, weakness, or paresis; hearing loss; auditory and facial nerve damage; cerebrospinal fluid leakage; infection; cerebellar damage; and death.Good pain relief was achieved in 81% of MVD patients and 88% of E-MVD patients, with a mean recurrence rate of 14% and 9%, respectively. Average rates of reported complications were statistically lower in E-MVD than in MVD approaches, including facial paresis or weakness, hearing loss, cerebellar damage, infection, and death, whereas cerebrospinal fluid leakage was similar. The overall incidence of complications was 19% for MVD and 8% for E-MVD.

CONCLUSIONS

The reviewed literature revealed similar clinical outcomes with respect to pain relief for MVD and E-MVD. The recurrence rate was lower in E-MVD studies, though not significantly so, and the incidence of complications, notably facial paresis and hearing loss, were statistically higher for MVD than for E-MVD. Based on these results, the use of endoscopy to perform MVD for TN appears to offer at least as good a surgical outcome as the more commonly used open MVD, with the possible added advantages of having a shorter operative time, smaller craniotomy, and lower recurrence rates. The authors advise caution in interpreting these data given the asymmetry in the sample size between the two groups and the relative novelty of the E-MVD approach.

Fully endoscopic microvascular decompression for hemifacial spasm

OBJECTIVE

Hemifacial spasm (HFS) is characterized by involuntary tonic and/or clonic contractions of facial nerve muscles. Fully endoscopic microvascular decompression (E-MVD) for HFS has not been widely adopted. This paper aims to illustrate the safety and efficacy of the fully endoscopic technique for HFS treatment.

METHODS

The authors conducted a single-center retrospective study of 27 patients (28 separate E-MVD cases; 1 patient had bilateral E-MVD) diagnosed with HFS who underwent fully E-MVD from January 2013 to October 2016. Intraoperative brainstem auditory evoked potentials and lateral spread resolution were reviewed. Outcome was based on the clinical status of the patient at the last contact point with the senior author. Complications were categorized as facial weakness, hearing loss, ataxia, dysphagia, or any adverse event able to be attributed to the surgical procedure.

RESULTS

HFS was relieved either completely or partially in the majority of cases (24 of 28, 85.7%). Of the 28 separate procedures, 17 (60.7%) resulted in complete resolution of symptoms, 4 (14.3%) resulted in near-complete resolution, 2 (7.1%) resulted in 50% reduction of symptoms, 1 (3.6%) resulted in minimal reduction, and 4 (14.3%) resulted in no relief. Of the 27 patients, 26 (96%) had no permanent postoperative complications. In multivariate logistic regression, the best predictor of greater than 50% resolution of spasm was resolution of intraoperative lateral spread response.

CONCLUSIONS

A fully E-MVD for HFS provides a safe and comprehensive view of the neurovascular conflict. Exclusive use of the endoscope in MVD is both safe and feasible in the treatment of HFS. Attention to lateral spread response monitoring remains an integral part of comprehensive neurosurgical management.

Pain threshold monitoring during chronic constriction injury of the infraorbital nerve in rats

Background: The chronic constriction injury (CCI) of the infraorbital nerve (ION) has been used to establish an animal mode of trigeminal neuralgia (TN), but key parameters of the model have not been quantified until now. Objective: The aim of the study was to quantify a standard of pain threshold to evaluate a successful TN model in Sprague-Dawley (SD) rats. Methods: Forty-eight adult SD rats (200-220 g) underwent chronic constriction injury of the infraorbital nerve. The pain threshold was tested one day preoperatively (baseline) and day 1, 3, 7, 14, 28 postoperatively using the up-down method. At day 28, all the animals were killed by dislocation of the cervical spine and the trigeminal nerve specimens were removed for electron microscopy. Results: The baseline pain threshold was 14.40 ± 0.87 g. Postoperatively, all the rats presented an initial reduced sensitivity to mechanical stimulation from day 1 (15.63 ± 1.92 g) through 7 (17.39 ± 1.43 g) after the surgery. At day 14, 32 (66.7%) began to show significant mechanical allodynia (0.71 ± 0.43 g) which did not change significantly till day 28 (0.88 ± 0.54 g). These animals were regarded as successful TN models with a 95% confidence interval of the pain threshold of 0.58-1.27 at Day 14. The electron microscopy demonstrated homogeneously demyelinated changes in those successful TN model animals rather than severe or mild epineurial lesions in those unsuccessful model animals. Conclusion: Our study showed that an animal TN model could be established with a two-week chronic constriction injury of the infraorbital nerve. The mechanical allodynia index <1.27 at Day 14 was suggested as a criterion for a successful model.

Endoscopic management of a low-grade thalamic glioma: a safe alternative to open microsurgery?

BACKGROUND

Despite considerable advances in preoperative and intraoperative imaging and neuronavigation, resection of thalamic gliomas remains challenging. Although both endoscopic biopsy and third ventriculostomy (ETV) for the treatment of secondary hydrocephalus are commonly performed, endoscopic resection of thalamic gliomas has been very sparsely described.

METHOD

We report and illustrate the surgical procedure and patient's outcome after full endoscopic resection of a thalamic glioma and to discuss this approach as an alternative to open microsurgery.

RESULTS

In 2016, a 56-year-old woman presented with disorientation, dysphasia and right facial hypaesthesia in our department. Cranial magnetic resonance imaging revealed a left thalamic lesion and subsequent hydrocephalus. Initially, hydrocephalus was treated by ETV but forceps biopsy was not diagnostic. However, metabolism in ¹⁸F-fluoroethyl-L-tyrosine positron emission tomography indicated glioma. Subsequently, endoscopic and neuronavigation-guided tumour resection was performed using a <1 cm², trans-sulcal approach through the left posterior horn of the lateral ventricle. While visibility was poor using the intraoperative microscope, neuroendoscopy provided excellent visualisation and allowed safe tumour debulking. Neither haemorrhage from the tumour or collapse of the cavity compromised endoscopic resection.

CONCLUSIONS

In accordance with one previously published case of endoscopic resection of a thalamic glioma, no surgery-related complications were observed. Although this remains to be determined in larger series, endoscopic resection of these lesions might be a safe and feasible alternative to biopsy or open surgery. Future studies should also aim to identify patients specifically eligible for these approaches.