A racial analysis of pain outcomes following microvascular decompression for trigeminal neuralgia

J Neurosurg 139:633–639, 2023

Pain outcomes by race in trigeminal neuralgia (TN) are not well investigated. The authors aimed to compare microvascular decompression (MVD) outcomes in TN patients on the basis of self-identified race.

METHODS The authors retrospectively reviewed all patients with TN who underwent MVD at their institution from 2007 to 2020. Each patient’s self-reported race was recorded, and Barrow Neurological Institute (BNI) scores for pain and numbness were compared. Factors associated with pain recurrence were assessed using survival analyses and multivariate regressions.

RESULTS Of 1011 patients, 925 reported their racial demographic characteristics, and patients who identified as Native American or American Indian and Native Hawaiian or Pacific Islander were excluded due to small sample sizes. Of the resulting 921 patients, 697 (75.7%) patients identified as White, 108 (11.7%) as Black or African American, 39 (4.2%) as Asian, and 77 (8.4%) as other. Compared with White patients, Black TN patients were more likely to present with type 1 TN (p = 0.02). At final follow-up, the mean BNI pain score of Black patients was significantly higher (p < 0.001) compared with that of White patients, although pain scores did not differ preoperatively. The adjusted multivariate ordinal regression model showed that Black patients were associated with higher BNI pain scores at final follow-up (p = 0.01). Furthermore, compared with White patients, Black patients were at increased risk for postoperative pain recurrence (p = 0.04), which additionally occurred after a shorter median pain-free duration (p = 0.03).

CONCLUSIONS TN patients who identify as Black or African American exhibit worse postoperative pain outcomes after MVD compared with White patients. Future studies investigating the factors driving these racial differences are warranted.

Effect of lesion temperature on the durability of percutaneous radiofrequency rhizotomies to treat trigeminal neuralgia

J Neurosurg 139:625–632, 2023

Percutaneous radiofrequency rhizotomy is a common procedure for trigeminal neuralgia (TN) that creates thermocoagulative lesions in the trigeminal ganglion. Lesioning parameters for the procedure are left to the individual surgeon’s discretion, and published guidance is primarily anecdotal. The purpose of this work was to assess the role of lesioning temperature on long-term surgical outcomes.

METHODS This was a retrospective analysis of patients who underwent percutaneous radiofrequency rhizotomy from 2009 to 2020. Patient data, including demographics, disease presentation, surgical treatment, and outcomes, were collected from medical records. The primary endpoint was the recurrence of TN pain. Univariate and multivariate Cox proportional hazards regressions were used to assess the impact of chosen covariates on pain-free survival.

RESULTS A total of 280 patients who had undergone 464 procedures were included in the analysis. Overall, roughly 80% of patients who underwent rhizotomy would have a recurrence within 10 years. Lower lesion temperature was predictive of longer periods without pain recurrence (HR 1.05, p < 0.001). The inclusion of lesion time, postoperative numbness, prior history of radiofrequency rhizotomy, surgeon, and multiple sclerosis as confounding variables did not affect the hazard ratio or the statistical significance of this finding. Postoperative numbness and the absence of multiple sclerosis were significant protective factors in the model.

CONCLUSIONS The study findings suggest that lower lesion temperatures and, separately, postoperative numbness result in improved long-term outcomes for patients with TN who undergo percutaneous radiofrequency rhizotomies. Given the limitations of retrospective analysis, the authors suggest that a prospective multisite clinical trial testing lesion temperatures would provide definitive guidance on this issue with specific recommendations about the number needed to treat and trial design.

Percutaneous Rhizotomy of the Gasserian Ganglion in Patients With Mass Lesion–Associated Trigeminal Neuralgia

Operative Neurosurgery 25:142–149, 2023

Patients with trigeminal neuralgia (TN) secondary to mass lesions are typically treated by directly addressing the underlying pathology. In cases of TN not alleviated by treatment of the pathology, percutaneous balloon compression (PBC) and glycerol rhizotomy (Gly) are simple and effective ways to alleviate pain. However, there is limited literature on the use of these techniques for patients with TN caused by mass lesions.

OBJECTIVE: To describe the use of PBC/Gly to treat mass lesion–related TN.

METHODS: We report a retrospective, single-institution, descriptive case series of patients who presented with TN secondary to tumor or mass-like inflammatory lesion from 1999 to 2021. Patients with primary, idiopathic, or multiple sclerosis–related TN were excluded. Outcomes included Barrow Neurological Institute (BNI) pain intensity and hypesthesia scores, pain persistence, and postoperative complications.

RESULTS: A total of 459 procedures were identified, of which 16 patients met the inclusion criterion (14 PBC and 2 Gly). Of the 15 patients with tumors, 12 had TN pain despite prior tumor-targeted radiation. Short-term (<3 months) BNI pain intensity improvement occurred in 15 (93.8%) patients. The mean follow-up was 54.4 months. Thirteen (81.3%) patients were pain-free (Barrow Neurological Institute pain intensity scale: IIIa–50%; I–25.0%; II–6.3%) for a mean of 23.8 (range 1137) months. Ten patients (62.5%) had pain relief for ≥6 months from first procedure. New facial numbness developed immediately postprocedure in 8 (50%) patients. Transient, partial abducens nerve palsy occurred in 1 patient.

CONCLUSION: PBC/Gly is an effective option for medically refractory TN in patients with mass-associated TN and is a viable option for repeat treatment.

Gamma Knife Stereotactic Radiosurgery for Trigeminal Neuralgia Secondary to Multiple Sclerosis

Neurosurgery 93:453–461, 2023

The efficacy of stereotactic radiosurgery (SRS) for the relief of trigeminal neuralgia (TN) is well established. Much less is known, however, about the benefit of SRS for multiple sclerosis (MS)–related TN (MS-TN). OBJECTIVE: To compare outcomes in patients who underwent SRS for MS-TN vs classical/idiopathic TN and identify relative risk factors for failure.

METHODS: We conducted a retrospective, case-control study of patients who underwent Gamma Knife radiosurgery at our center for MS-TN between October 2004 and November 2017. Cases were matched 1:1 to controls using a propensity score predicting MS probability using pretreatment variables. The final cohort consisted of 154 patients (77 cases and 77 controls). Baseline demographics, pain characteristics, and MRI features were collected before treatment. Pain evolution and complications were obtained at follow-up. Outcomes were analyzed using the Kaplan-Meir estimator and Cox regressions.

RESULTS: There was no statistically significant difference between both groups with regards to initial pain relief (modified Barrow National Institute IIIa or less), which was achieved in 77% of patients with MS and 69% of controls. In responders, 78% of patients with MS and 52% of controls eventually had recurrence. Pain recurred earlier in patients with MS (29 months) than in controls (75 months). Complications were similarly distributed in each group and consisted, in the MS group, of 3% of new bothersome facial hypoesthesia and 1% of new dysesthesia.

CONCLUSION: SRS is a safe and effective modality to achieve pain freedom in MS-TN. However, pain relief is significantly less durable than in matched controls without MS.

Augmented Reality–Assisted Percutaneous Rhizotomy for Trigeminal Neuralgia

Operative Neurosurgery 24:665–669, 2023

Percutaneous rhizotomy of the trigeminal nerve is a common surgery to manage medically refractory trigeminal neuralgia. Traditionally, these procedures have been performed based on anatomic landmarks with fluoroscopic guidance. Augmented reality (AR) relays virtual content on the real world and has the potential to improve localization of surgical targets based on preoperative imaging.

OBJECTIVE: To study the potential application and benefits of AR as an adjunct to traditional fluoroscopy-guided glycerol rhizotomy (GR).

METHODS: We used traditional fluoroscopy-guided percutaneous GR technique as previously described, performed under general anesthesia. Anatomic registration to the Medivis SurgicalAR system was performed based on the patient’s preoperative computerized tomography, and the surgeon was equipped with the system’s AR goggles. AR was used as an adjunct to fluoroscopy for trajectory planning to place a spinal needle into the medial aspect of the foramen ovale.

RESULTS: A 50-year-old woman with multiple sclerosis–related right-sided classical trigeminal neuralgia had persistent pain, refractory to medications, previous gamma knife stereotactic radiosurgery, and percutaneous radiofrequency rhizotomy performed elsewhere. The patient underwent AR-assisted fluoroscopy-guided percutaneous GR. The needle was placed into the right trigeminal cistern within seconds. She was discharged home after a few hours of observation with no complications and reported pain relief.

CONCLUSION: AR-assisted percutaneous rhizotomy may enhance the learning curve of these types of procedures and decrease surgery duration and radiation exposure. This allowed rapid and correct placement of a spinal needle through the foramen ovale.

Multiple Vessel Compression of the Trigeminal Nerve Is Associated With Worse Outcomes in Trigeminal Neuralgia After Microvascular Decompression

Neurosurgery 92:1029–1034, 2023

Whether the total number of compressive vessels in trigeminal neuralgia (TN) affects outcomes after microvascular decompression (MVD) is unknown.

OBJECTIVE: To investigate whether the number of compressive vessels is associated with outcomes after MVD.

METHODS: We retrospectively reviewed all patients with TN who underwent MVDs at our institution from 2007 to 2020. The number and identity of compressive vessels on the trigeminal nerve were recorded. Preoperative and postoperative pain and numbness Barrow Neurological Institute scores were compared. Factors associated with pain recurrence were assessed using survival analyses and multivariate regressions.

RESULTS: We identified 496 patients with a single vessel and 381 patients with multiple vessels compressing the trigeminal nerve. Compared with patients with a single compressive vessel, patients with multiple sources of compression exhibited increased Barrow Neurological Institute pain scores preoperatively (P = .01). In addition, pain recurrence was more frequent (P < .001) and occurred after a significantly shorter pain-free duration (P < .001) for the multiple compression group. Using multivariate ordinal regression, a greater number of arteries (P = .03) and veins (P = .03) were both significantly associated with higher pain scores at final follow-up. Furthermore, the number of arteries (P = .01) and of veins (P = .01) was significantly associated with a higher risk for pain recurrence.

CONCLUSION: TN patients with a single compressive vessel exhibited better pain outcomes after an MVD. Patients with multiple compressive vessels exhibited higher pain scores preoperatively and incurred a higher risk for pain recurrence, which occurred after a shorter pain-free interval compared with the single compression cohort.

Refining the Anatomy of Percutaneous Trigeminal Rhizotomy: A Cadaveric, Radiological, and Surgical Study

Operative Neurosurgery 24:341–349, 2023

Percutaneous trigeminal rhizotomy (PTR) is a widely used procedure for trigeminal neuralgia. However, comprehensive analyses that combine anatomic, radiological, and surgical considerations are rare.

OBJECTIVE: To present high-quality anatomic dissections and radiological studies that highlight the technical nuances of this procedure.

METHODS: Six silicon-injected postmortem heads underwent PTR. The surgical corridors were dissected, and the neurovascular relationships were studied. In addition, 20 dried human skulls and 50 computed tomography angiography and MRI scans were collected to study the anatomic relationships for a customized puncture corridor.

RESULTS: The PTR corridor was divided into 3 segments: the buccal segment (length, 34.76 ± 7.20 mm), the inferior temporal fossa segment (length, 42.06 ± 6.92 mm), and the Meckel cave segment (length, 24.75 ± 3.34 mm). The puncture sagittal (α) and axial (β) angles measured in this study were 38.32° ± 4.62° and 19.13° ± 2.82°, respectively. The precondylar reference line coincided with the foramen ovale in 75% of the computed tomography angiography scans, and the postcondylar line coincided with the carotid canal in 70% of the computed tomography angiography scans; these lines serve as the intraoperative landmarks for PTR. The ovale-carotid-pterygoid triangle, delineated by drawing a line from the foramen ovale to the carotid canal and the lateral pterygoid plate, is a distinguished landmark to use for avoiding neurovascular injury during fluoroscopy.

CONCLUSION: Knowledge of the anatomic and radiological features of PTR is essential for a successful surgery, and a customized technical flow is a safe and effective way to access the foramen ovale.

A Case Series of Trigeminal Neuralgia With Pure Venous Compression: Postoperative Outcomes Associated With Intraoperative Venous Transposition Versus Coagulation

Operative Neurosurgery 24:377–382, 2023

Microvascular decompressions (MVDs) are effective open-surgical procedures for trigeminal neuralgia (TN). Intraoperative management of compressive veins may include either venous transposition or coagulation. Although both are generally considered safe,which technique results in optimal postoperative outcomes remains unclear.

OBJECTIVE: To compare postoperative pain and numbness outcomes after an MVD in patients with TN of exclusive venous compression.

METHODS: We retrospectively reviewed all patients with TN who underwent MVDs at our institution from 2007 to 2020. Patients with TN of pure venous compression were identified using MRI imaging, which was subsequently confirmed intraoperatively. Patient demographics, procedural characteristics, and postoperative pain and numbness scores were recorded and compared. Factors associated with pain recurrence were assessed using survival analyses and multivariate regressions.

RESULTS: We identified 181 patients who presented with TN of pure venous compression. Using a multivariate linear regression, adjusted for age, sex, and presence of multiple sclerosis, use of venous transposition vs coagulation was not significantly associated with the Barrow Neurological Institute pain score at final follow-up, although venous transposition was significantly predictive of a worse postoperative Barrow Neurological Institute numbness score (P = .003). Using a Kaplan–Meier survival analysis and a multivariate Cox proportional hazards regression, respectively, venous transposition was significantly associated with faster (P = .01) as well as higher risk for pain recurrence (P = .01).

CONCLUSION: The use of venous coagulation during an MVD is associated with better postoperative pain and numbness outcomes. The results of our study may help inform preoperative patient counseling and surgical management for TN cases that involve pure venous compression.

Factors Predicting Cerebrospinal Fluid Leaks in Microvascular Decompressions: A Case Series of 1011 Patients

Operative Neurosurgery 24(3):p 262-267, March 2023.

Microvascular decompression (MVD) using a retrosigmoid approach is a highly effective, open-surgical procedure for neurovascular conflict in the posterior fossa, although there is a risk of postoperative cerebrospinal fluid (CSF) leak.

To identify factors associated with postoperative CSF leakage after MVD.

We retrospectively reviewed all patients who underwent MVDs at our institution from 2007 to 2020. Patient demographics, clinical diagnoses, and procedural characteristics were recorded and compared. Factors leading to CSF leak were analyzed using χ2, univariate, and multivariate regression.

Of 1011 patients who underwent MVDs, 37 (3.7%) presented with postoperative CSF leaks. In univariate analysis, the use of Cranios/Norian to obliterate the air cells was protective against CSF leak (P = .01). Craniotomies (P = .002), the use of dural substitutes such as Durepair (P = .04), dural onlays such as DuraGen (P = .04), muscle/fascia (P = .03), and titanium mesh cranioplasty >5 cm (P = .03) were associated with CSF leak. On multivariate analysis, only the presence of craniotomies (P = .04) and nonprimary dural closure (P = .03) were significant risk factors for CSF leak. When excluding the 34 (3.4%) patients who underwent a craniotomy, the lack of primary dural closure still remained significantly associated with postoperative CSF leak (P = .04).

Our results represent one of the largest series of posterior fossa surgeries for a uniform indication in North America. Our study demonstrates increased risk for postoperative CSF leak when craniotomies are performed and when primary dural closure is not established. Given the small sample of patients who received a craniotomy, however, future studies corroborating this finding should be performed.

Sacrifice or preserve the superior petrosal vein in microvascular decompression surgery

J Neurosurg 138:390–398, 2023

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.


Increase in Trigeminal Nerve Cross-Sectional Area on Immediate Postoperative MRI Predicts Favorable Outcome After Microvascular Decompression for Classical Trigeminal Neuralgia

Neurosurgery 92:283–292, 2023

Although distortion or indentation of a trigeminal nerve due to neurovascular compression (NVC) is associated with classical trigeminal neuralgia, whether morphological change in the trigeminal nerve is relieved by eliminating NVC has not been studied.

OBJECTIVE: To estimate morphological change in the trigeminal nerve after microvascular decompression (MVD).

METHODS: Fifty patients with classical trigeminal neuralgia who underwent MVD were included. Using coronal images in both preoperative and postoperative MRI, the trigeminal nerve cross-sectional area (CSA) was measured at 4 mm anterior to the nerve entry into the pons. Clinical outcomes were assessed using the Barrow Neurological Institute Pain Intensity Scale (BNI-PS) at the patient’s latest follow-up.

RESULTS: Forty-one patients achieved favorable outcomes without medication (BNI-PS I or II), and 9 patients had residual pain (BNI-PS ≥ 3A). The mean symptomatic trigeminal nerve CSA was increased by 51.47% after MVD in the favorable outcome group (pre-operative: 4.37 ± 1.64 mm 2 vs postoperative: 6.26 ± 1.76 mm2 , P < .01), whereas it was not significantly changed in the unfavorable outcome group (preoperative: 4.20 ± 1.19 mm2 vs postoperative: 4.43 ± 1.24 mm2 , P = .69). Kaplan–Meier survival analysis showed that the 3-year probability of maintaining a favorable outcome was 92.3 ± 7.4% and 56.1 ± 11.9%, for those whose symptomatic trigeminal nerve CSA was increased by over 20% and less than 20%, respectively (P < .01).

CONCLUSION: Morphological changes in the trigeminal nerve due to NVC could be recovered by MVD, and increases in the trigeminal nerve CSA predicted favorable outcomes.

Internal neurolysis versus intraoperative glycerin rhizotomy for trigeminal neuralgia

J Neurosurg 138:270–275, 2023

Internal neurolysis (IN) and intraoperative glycerin rhizotomy (ioGR) are emerging surgical options for patients with trigeminal neuralgia without neurovascular contact. The objective of this study was to compare the neurological outcomes of patients who underwent IN with those of patients who underwent ioGR.

METHODS The authors retrospectively reviewed all patients who underwent IN or ioGR for trigeminal neuralgia at our institution. Patient demographic characteristics and immediate postoperative outcomes, as well as long-term neurological outcomes, were compared.

RESULTS Of 1044 patients who underwent open surgical treatment for trigeminal neuralgia, 56 patients underwent IN and 91 underwent ioGR. Of these 147 patients, 37 had no evidence of intraoperative neurovascular conflict. All patients who underwent IN and 96.7% of patients who underwent ioGR had immediate postoperative pain relief. At last followup, patients who underwent IN had lower Barrow Neurological Institute (BNI) pain intensity scores (p = 0.05), better BNI facial numbness scores (p < 0.01), and a greater degree of pain improvement (p = 0.05) compared with those who underwent ioGR. Patients who underwent IN also had significantly lower rates of symptomatic pain recurrence (p < 0.01) at last follow-up over an average of 9.5 months.

CONCLUSIONS IN appears to provide patients with a greater degree of pain relief, lower rates of facial numbness, and lower rates of pain recurrence compared with ioGR. Future prospective studies will better characterize long-term pain recurrence and outcomes.


Technical Assessment of Microvascular Decompression for Trigeminal Neuralgia Using a 3-Dimensional Exoscope

Operative Neurosurgery 23:374–381, 2022

Detailed anatomic visualization of the root entry zone of the trigeminal nerve is crucial to successfully perform microvascular decompression surgery (MVD) in patients with trigeminal neuralgia.

OBJECTIVE: To determine advantages and disadvantages using a 3-dimensional (3D) exoscope for MVD surgery.

METHODS: A 4K 3D exoscope (ORBEYE) was used by a single surgical team for MVD in a retrospective case series of 8 patients with trigeminal neuralgia in a tertiary center. Clinical and surgical data were collected, and advantages/disadvantages of using the exoscope for MVD were recorded after each surgery. Descriptive statistics were used to summarize the data.

RESULTS: Adequate MVD of the trigeminal nerve root was possible in all patients by exclusively using the exoscope. It offered bright visualization of the cerebellopontine angle and the root entry zone of the trigeminal nerve that was comparable with a binocular operating microscope. The greatest advantages of the exoscope included good optical quality, the pronounced depth of field of the image for all observers, and its superior surgeon ergonomics. Disadvantages were revealed with overexposure at deep surgical sites and the lack of endoscope integration. In 6 patients, facial pain improved significantly after surgery (Barrow Neurological Institute pain intensity score I in 5 and III in 1 patient), whereas it did not in 2 patients (Barrow Neurological Institute score IV and V). No complications occurred.

CONCLUSION: Utilization of a 3D exoscope for MVD is a safe and feasible procedure. Surgeons benefit from better ergonomics, excellent image quality, and an improved experience for observers.

Incidence of repeat procedures and healthcare utilization following surgery, radiosurgery, and percutaneous procedures in elderly patients with trigeminal neuralgia

J Neurosurg 137:828–839, 2022

Management of trigeminal neuralgia (TN) in elderly patients poses significant challenges. The impact of different treatment modalities (surgery, radiosurgery [RS], and percutaneous techniques [PTs]) on healthcare utilization is not well defined in the management of TN in elderly patients. The aim of this study was to compare the long-term healthcare utilization metrics of different interventions in the management of elderly patients with TN.

METHODS The MarketScan database was queried using the International Classification of Diseases, Ninth Revision and Current Procedural Terminology, from 2000 to 2016. TN patients ≥ 65 years of age managed using surgery, RS, and PTs with at least 5 years of follow-up after the index procedure were included. Outcomes analyzed were hospital admissions, outpatient services, and medication refills.

RESULTS Of 993 patients, 43% (n = 430) underwent RS, 44% (n = 432) had PTs, and only 13% (n = 131) underwent surgery for TN. Overall, the median age of patients was 74 years old, 64% were females, 90% had Medicare insurance, and 17% had an Elixhauser index ≥ 3. Patients in the surgery group were younger (median age 71 years) with a higher comorbidity index (≥ 3; 24%) compared with patients undergoing RS and PTs (13% and 17%, respectively). At 1, 2, and 5 years after the index procedure, 41%, 48%, and 57% of patients in the PT cohort underwent any repeat procedure compared with 11%, 18%, and 29% for the RS cohort, and 6%, 9%, and 11% for the surgical cohort, respectively. Also, patients in the PT cohort incurred 1.8, 1.9, and 2.0 times the combined payment at 1, 2, and 5 years, respectively, compared with the surgery cohort. Similarly, patients who underwent RS for TN incurred 1.4, 1.5, and 1.5 times the combined payment at 1, 2, and 5 years, respectively, compared with the surgery cohort. At 5 years after the index procedure, combined payments for the PT cohort were $79,753 (IQR $46,013, $144,064) compared with $61,016 (IQR $27,114, $117,097) for the RS cohort and $41,074 (IQR $25,392, $87,952) for the surgery cohort (p < 0.0001).

CONCLUSIONS PTs followed by RS were the common procedures used in the majority of elderly patients with TN. However, surgery for TN resulted in durable control with the least need for reoperations up to 5 years after the index procedure, followed by RS and PTs. PTs for TN resulted in the highest utilization of healthcare resources and need for reoperations at all time points. These findings should be considered in clinical decision-making when selecting appropriate treatment modalities in elderly patients with TN.

Purely venous compression in trigeminal neuralgia—can we predict the outcome of surgery

Acta Neurochirurgica (2022) 164:1567–1573

Controversies regarding venous compression and trigeminal neuralgia (TN) still exist. The study demonstrates our experience for microvascular decompression (MVD) in TN caused by purely venous compression. The goal was to identify prognostic anatomical or surgical factors that may influence the outcome.

Methods Between 2004 and 2020, 49 patients were operated with purely venous compression. Average age was 58.4 years. Mean history of TN was 7.8 years. Microsurgical procedures included transposition or separation of the vein, coagulation, and division. Several features have been analyzed with respect to BNI scores.

Results Evaluation on discharge revealed a complete pain relief in 39 (80%), partial improvement in 7 (14%), and no benefit in 3 (6%) patients. Facial hypesthesia was reported by 14 (28.6%) patients. Mean follow-up (FU) was 42.1 months. BNI pain intensity score on FU revealed 71.4% excellent to very good scores (score 1: 32 (65.3%); 2: 3 (6.1%)). BNI facial numb- ness score 2 could be detected in 13 patients (26.5%) during FU. There was no statistical relationship between immediate pain improvement or BNI pain intensity score on FU with respect to surgical procedure, size of trigeminal cistern, type of venous compression, venous caliber, trigeminal nerve indentation, or neurovascular adherence. BNI facial numbness score was dependent on type of venous compression (p < 0.05).

Conclusion We did not find typical anatomical features that could either predict or influence the outcome regarding pain improvement or resolution in any form. Neither classic microvascular decompression (interposition/transposition) nor sacrificing the offending vein made any difference in outcome.

The impact of needle location on clinical outcome of radiofrequency rhizotomy for trigeminal neuralgia

Acta Neurochirurgica (2022) 164:1575–1585

Radiofrequency thermocoagulation trigeminal rhizotomy (RT-TR) through the foramen ovale is a minimally invasive treatment for trigeminal neuralgia. Navigation of magnetic resonance imaging (MRI) and CT fusion imaging is a well-established method for cannulation of the Gasserian ganglion. In this study, we use the inline measurements from fusion image to analyze the anatomical parameters between the actual and simulation trajectories and compare the short- and intermediate-term outcomes according to determinable factors.

Methods The study included thirty-six idiopathic neuralgia patients who had undergone RT-TR with MRI and CT fusion image as a primary modality or repeated procedures.

Results Among thirty-six treated patients, the inline length of the trigeminal cistern was longer for the simulated trajectory (8.4 ± 2.4 versus 6.5 ± 2.8 mm; p < 0.05), and the predominant structure at risk extrapolated from the inline trajectory was the brainstem, which signified a more medially directed route, in contrast with the equal weighting of temporal lobe and brainstem for the actual trajectory. The preoperative visual analogue scale (VAS) was 9.3 ± 1.0, which decreased to 2.5 ± 2.6 and 2.9 ± 3.1 at first (mean, 3 months) and second (mean, 14 months) postoperative follow-up, respectively. The postoperative VAS scores at the two follow-ups were not statistically significant without a covariate analysis. After adjustment for covariate risk factors, the second follow-up sustained therapeutic benefit was evident in patients with no prior history of related treatment, an ablation temperature greater than 70 °C, and needle location within or adjacent to the trigeminal cistern.

Conclusions This preliminary study demonstrated that the needle location between cistern and ganglion also plays a significant role in better intermediate-term results.

Treatment Strategies for Different Types of Intraneural Offending Vessels in Microvascular Decompression Surgery for Trigeminal Neuralgia

Neurosurgery 90:562–568, 2022

Microvascular decompression (MVD) surgery is the treatment of choice for trigeminal neuralgia (TGN). However, decompression becomes difficult when the offending vessel penetrates the trigeminal nerve root.

OBJECTIVE: To estimate the rates and patterns of different types of intraneural offending vessels in patients with TGN for MVD and to discuss respective management strategies. METHODS: All patients with TGN undergoing MVD in our center from January 1, 2015, to December 31, 2019, were analyzed retrospectively. The intraneural offending vessels included veins and arteries. The postoperative pain relief rate, complications, and recurrences were evaluated.

RESULTS: Of the 302 TGN cases, the intraneural offending vessels were identified in 58 of the cases (19.2%). The 9 cases (15.5%) of intraneural offending arteries were decompressed using shredded Teflon wrapping interposition. Of the 49 cases (84.5%) of intraneural offending veins (INOVs), 29 were not considered true offending vessels, and the treatment only addressed the offending artery in these patients. Of the remaining 20 INOVs, 15 were electrocoagulated and divided, and 5 were decompressed with shredded Teflon. Complete pain relief was achieved in all 58 patients. However, the pain recurred in 5 patients (8.6%), and transient hemifacial numbness occurred in 4 patients (6.9%).

CONCLUSION: Intraneural offending vessels requiring treatment are uncommon and are seen in less than 1 in 10 patients undergoing MVD for TGN. For intraneural offending artery, decompression by shredded Teflon wrapping interposition is recommended. Management of the INOV depends on the individual situations, and the management includes sacrifice, wrapping decompression, or leaving them untreated.


The Long-Term Outcome of Radiofrequency Ablation in Multiple Sclerosis–Related Symptomatic Trigeminal Neuralgia

Neurosurgery 90:293–299, 2022

Radiofrequency lesioning (RFL) is used to surgically manage trigeminal neuralgia (TN) secondary to multiple sclerosis (MS). However, the long-term outcome of RFL has not been established.

OBJECTIVE: To investigate the long-term clinical outcome of RFL in MS-related TN (symptomatic trigeminal neuralgia [STN]).

METHODS: During a 23-yr period, institutional data were available for 51 patients with STN who underwent at least one RFL procedure to treat facial pain. Patient outcome was evaluated at a mean follow-up of 69 mo (95% confidence interval; range 52-86 mo). No pain with no medication (NPNM) was the primary long-term outcome measure.

RESULTS: After an initial RFL procedure, immediate pain relief was achieved in 50 patients (98%), and NPNM as assessed at 1, 3, and 6 yr was 86%, 52%, and 22%, respectively. At the last clinical visit after an initial RFL, 23 patients (45%) with pain recurrence underwent repeat RFL; NPNM at 1, 3, and 6 yr after a repeat RFL was 85%, 58%, and 32%, respectively. There was no difference in pain outcome after an initial and repeat RFL (P = .77). Ten patients with pain recurrence underwent additional RFL procedures. Two patients developed mastication muscle weakness, one patient experienced a corneal abrasion, which resolved with early ophthalmological interventions, and one patient experienced bothersome numbness.

CONCLUSION: RFL achieves NPNM status in STN and can be repeated with similar efficacy.

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

World Neurosurg. (2022) 158:226-233

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

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

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

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

Results of three or more Gamma Knife radiosurgery procedures for recurrent trigeminal neuralgia

J Neurosurg 135:1789–1798, 2021

Gamma Knife radiosurgery (GKRS) is an established surgical option for the treatment of trigeminal neuralgia (TN), particularly for high-risk surgical candidates and those with recurrent pain. However, outcomes after three or more GKRS treatments have rarely been reported. Herein, the authors reviewed outcomes among patients who had undergone three or more GKRS procedures for recurrent TN.

METHODS The authors conducted a multicenter retrospective analysis of patients who had undergone at least three GKRS treatments for TN between July 1997 and April 2019 at two different institutions. Clinical characteristics, radiosurgical dosimetry and technique, pain outcomes, and complications were reviewed. Pain outcomes were scored on the Barrow Neurological Institute (BNI) scale, including time to pain relief (BNI score ≤ III) and recurrence (BNI score > III).

RESULTS A total of 30 patients were identified, including 16 women and 14 men. Median pain duration prior to the first GKRS treatment was 10 years. Three patients (10%) had multiple sclerosis. Time to pain relief was longer after the third treatment (p = 0.0003), whereas time to pain recurrence was similar across each of the successive treatments (p = 0.842). Complete or partial pain relief was achieved in 93.1% of patients after the third treatment. The maximum pain relief achieved after the third treatment was significantly better among patients with no prior percutaneous procedures (p = 0.0111) and patients with shorter durations of pain before initiation of GKRS therapy (p = 0.0449). New or progressive facial sensory dysfunction occurred in 29% of patients after the third GKRS treatment and was reported as bothersome in 14%. One patient developed facial twitching, while another experienced persistent lacrimation. No statistically significant predictors of adverse effects following the third treatment were found. Over a median of 39 months of follow-up, 77% of patients maintained complete or partial pain relief. Three patients underwent a fourth GKRS treatment, including one who ultimately received five treatments; all of them reported sustained pain relief at the extended follow-up.

CONCLUSIONS The authors describe the largest series to date of patients undergoing three or more GKRS treatments for refractory TN. A third treatment may produce outcomes similar to those of the first two treatments in terms of longterm pain relief, recurrence, and adverse effects.


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