Microvascular decompression in trigeminal neuralgia - a prospective study of 115 patients

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.

Factors associated with outcomes following microvascular decompression for the treatment of primary trigeminal neuralgia in adults: a systematic review and meta-analysis

This study aimed to evaluate pain assessment strategies and factors associated with outcomes after microvascular decompression for the treatment of primary trigeminal neuralgia in adults. We conducted a systematic review and meta-analysis of English, Spanish, and French literature. We searched three databases, PubMed, Ovid, and EBSCO, from 2010 to 2022 and selected studies including patients with primary trigeminal neuralgia, clear pain assessment, and pain outcomes. Population means and standard deviations were calculated. Studies that included factors associated with postoperative outcomes were included in the meta-analysis. A total of 995 studies involving 5673 patients with primary trigeminal neuralgia following microvascular decompression were included. Patients with arteries compressing the trigeminal nerve demonstrated optimal outcomes following microvascular decompression (odds ratio [OR]= 0.39; 95% confidence interval [CI] = 0.19-0.80; X2 = 46.31; Dof = 15; I2 = 68%; P = < 0.0001). Conversely, when comparing arterial vs venous compression of the trigeminal nerve (OR = 2.72; 95% CI = 1.16-6.38; X2 = 23.23; Dof = 10; I2 = 57%; P = 0.01), venous compression demonstrated poor outcomes after microvascular decompression. Additionally, when comparing single-vessel vs multiple-vessel compression (OR = 2.72; 95% CI = 1.18-6.25; X2 = 21.17; Dof = 9; I2 = 57%; P = 0.01), patients demonstrated unfavorable outcomes after microvascular decompression. This systematic review and meta-analysis evaluated factors associated with outcomes following microvascular decompression (MVD) for primary trigeminal neuralgia (PTN). Although MVD is an optimal treatment strategy for PTN, a gap exists in interpreting the results when considering the lack of evidence for most pain assessment strategies.

A causal effect study of cortical morphology and related covariate networks in classical trigeminal neuralgia patients

Structural covariance networks and causal effects within can provide critical information on gray matter reorganization and disease-related hierarchical changes. Based on the T1WI data of 43 classical trigeminal neuralgia patients and 45 controls, we constructed morphological similarity networks of cortical thickness, sulcal depth, fractal dimension, and gyrification index. Moreover, causal structural covariance network analyses were conducted in regions with morphological abnormalities or altered nodal properties, respectively. We found that patients showed reduced sulcal depth, gyrification index, and fractal dimension, especially in the salience network and the default mode network. Additionally, the integration of the fractal dimension and sulcal depth networks was significantly reduced, accompanied by decreased nodal efficiency of the bilateral temporal poles, and right pericalcarine cortex within the sulcal depth network. Negative causal effects existed from the left insula to the right caudal anterior cingulate cortex in the gyrification index map, also from bilateral temporal poles to right pericalcarine cortex within the sulcal depth network. Collectively, patients exhibited impaired integrity of the covariance networks in addition to the abnormal gray matter morphology in the salience network and default mode network. Furthermore, the patients may experience progressive impairment in the salience network and from the limbic system to the sensory system in network topology, respectively.

Trigeminal neuralgia

Trigeminal neuralgia (TN) is a facial pain disorder characterized by intense and paroxysmal pain that profoundly affects quality of life and presents complex challenges in diagnosis and treatment. TN can be categorized as classical, secondary and idiopathic. Epidemiological studies show variable incidence rates and an increased prevalence in women and in the elderly, with familial cases suggesting genetic factors. The pathophysiology of TN is multifactorial and involves genetic predisposition, anatomical changes, and neurophysiological factors, leading to hyperexcitable neuronal states, central sensitization and widespread neural plasticity changes. Neurovascular compression of the trigeminal root, which undergoes major morphological changes, and focal demyelination of primary trigeminal afferents are key aetiological factors in TN. Structural and functional brain imaging studies in patients with TN demonstrated abnormalities in brain regions responsible for pain modulation and emotional processing of pain. Treatment of TN involves a multifaceted approach that considers patient-specific factors, including the type of TN, with initial pharmacotherapy followed by surgical options if necessary. First-line pharmacological treatments include carbamazepine and oxcarbazepine. Surgical interventions, including microvascular decompression and percutaneous neuroablative procedures, can be considered at an early stage if pharmacotherapy is not sufficient for pain control or has intolerable adverse effects or contraindications.

Exploring the mechanism of Nav1.3 in the ION-CCI rat model based on the TLR4/TRAF6/NF-κB pathway

BACKGROUND

Trigeminal neuralgia (TN) is a common and difficult-to-treat neuropathic pain disorder in clinical practice. Previous studies have shown that Toll-like receptor 4 (TLR4) modulates the activation of the NF-κB pathway to affect neuropathic pain in rats. Voltage-gated sodium channels (VGSCs) are known to play an important role in neuropathic pain electrical activity.

OBJECTIVE

To investigate whether TLR4 can regulate Nav1.3 through the TRAF6/NF-κB p65 pathway after infraorbital nerve chronic constriction injury (ION-CCI).

STUDY DESIGN

ION-CCI modeling was performed on SD (Sprague Dawley) rats. To verify the success of the modeling, we need to detect the mechanical pain threshold and ATF3. Then, detecting the expression of TLR4, TRAF6, NF-κB p65, p-p65, and Nav1.3 in rat TG. Subsequently, investigate the role of TLR4/TRAF6/NF-κB pathway in ION-CCI model by intrathecal injections of LPS-rs (TLR4 antagonist), C25-140 (TRAF6 inhibitor), and PDTC (NF-κB p65 inhibitor).

RESULTS

ION-CCI surgery decreased the mechanical pain threshold of rats and increased the expression of ATF3, TLR4, TRAF6, NF-κB p-p65 and Nav1.3, but there was no difference in NF-κB p65 expression. After inject antagonist or inhibitor of the TLR4/TRAF6/NF-κB pathway, the expression of Nav1.3 was decreased and mechanical pain threshold was increased.

CONCLUSION

In the rat model of ION-CCI, TLR4 in the rat trigeminal ganglion regulates Nav1.3 through the TRAF6/NF-κB p65 pathway, and TLR4 antagonist alleviates neuropathic pain in ION-CCI rats.

Efficacy and safety of microvascular decompression with or without partial sensory rhizotomy: a comprehensive meta-analysis and systematic review in treating trigeminal neuralgia

Classical trigeminal neuralgia (TN), caused by vascular compression of the nerve root, is a severe cause of pain with a considerable impact on a patient's quality of life. While microvascular decompression (MVD) has lower recurrence rates when compared with partial sensory rhizotomy (PSR) alone, refractoriness can still be as high as 47%. We aimed to assess the efficacy and safety profile of MVD + PSR when compared to standalone MVD for TN. We searched Medline, Embase, and Web of Science following PRISMA guidelines. Eligible studies included those with ≥ 4 patients, in English, published between January 1980 and December 2023, comparing MVD vs. MVD + PSR for TN. Endpoints were pain cure, immediate post-operative pain improvement, long-term effectiveness, long-term recurrence, and complications (facial numbness, hearing loss, and intracranial bleeding). We pooled odds ratios (OR) with 95% confidence intervals with a random-effects model. I2 was used to assess heterogeneity, and sensitivity and Baujat analysis were conducted to address high heterogeneity. Eight studies were included, comprising a total of 1,338 patients, of whom 1,011 were treated with MVD and 327 with MVD + PSR. Pain cure analysis revealed a lower likelihood of pain cure in patients treated with MVD when compared to patients treated with MVD + PSR (OR = 0.30, 95% CI: 0.13 to 0.72). Immediate postoperative pain improvement assessment revealed a lower likelihood of improvement in the MVD group when compared with the MVD + PSR group (OR = 0.31, 95% CI: 0.10 to 0.95). Facial numbness assessment revealed a lower likelihood of occurrence in MVD alone when compared to MVD + PSR (OR = 0.08, 95% CI: 0.04 to 0.15). Long-term effectiveness, long-term recurrence, hearing loss, and intracranial bleeding analyses revealed no difference between both approaches. Our meta-analysis identified that MVD + PSR was superior to MVD for pain cure and immediate postoperative pain improvement for treating TN. However, MVD + PSR demonstrated a higher likelihood of facial numbness complications. Furthermore, identified that hearing loss and intracranial bleeding complications appear comparable between the two treatments, and no difference between long-term effectiveness and recurrence.

A nomogram based on radiomics and clinical information to predict prognosis in percutaneous balloon compression for the treatment of trigeminal neuralgia

OBJECTIVE

To develop a clinical-radiomics nomogram based on clinical information and radiomics features to predict the prognosis of percutaneous balloon compression (PBC) for the treatment of trigeminal neuralgia (TN).

METHODS

The retrospective study involved clinical data from 149 TN patients undergoing PBC at Zhongnan Hospital, Wuhan University from January 2018 to January 2022. The free open-source software 3D Slicer was used to extract all radiomic features from the intraoperative X-ray balloon region. The relationship between clinical information and TN prognosis was analyzed by univariate logistic analysis and multivariate logistic analysis. Using R software, the optimal radiomics features were selected using the least absolute shrinkage and selection operator (Lasso) algorithm. A prediction model was constructed based on the clinical information and radiomic features, and a nomogram was visualized. The performance of the clinical radiomics nomogram in predicting the prognosis of PBC in TN treatment was evaluated using the area under the receiver operating characteristic curve (AUC) and decision curve analysis (DCA).

RESULTS

A total of 149 patients were eventually included. The clinical factors influencing the prognosis of TN in univariate analysis were compression severity score and TN type. The lasso algorithm Max-Relevance and Min-Redundancy(mRMR) was used to select two predictors from 13 morphology-related radiomics features, including elongation and surface-volume ratio. A total of 4 predictors were used to construct a prediction model and nomogram. The AUC was 0.886(95% confidence interval (CI), 0.75 to 0.96), indicating that the model's good predictive ability. DCA demonstrated the nomogram's high clinical applicability.

CONCLUSION

Clinical-radiomics nomogram constructed by combining clinical information and morphology-related radiomics features have good potential in predicting the prognosis of TN for PBC treatment. However, this needs to be further studied and validated in several independent external patient populations.

Safety and efficacy of carbamazepine in the treatment of trigeminal neuralgia: A metanalysis in biomedicine

Trigeminal neuralgia is a debilitating condition characterized by severe facial pain. Carbamazepine has been widely used as a first-line treatment option for trigeminal neuralgia, but there is a need to evaluate its safety and efficacy based on existing evidence. This meta-analysis aims to systematically assess the available literature and provide a comprehensive evaluation of the safety and efficacy of carbamazepine in the treatment of trigeminal neuralgia. A thorough search of electronic databases yielded a total of 15 relevant studies that met the inclusion criteria. The pooled analysis of these studies revealed that carbamazepine demonstrated significant efficacy in reducing pain intensity and frequency in patients with trigeminal neuralgia. Moreover, the drug was generally well-tolerated, with the most common adverse events being mild and transient. Subgroup analyses based on different dosages and treatment durations further supported the overall findings. However, caution should be exercised in patients with certain comorbidities or specific populations, as some rare but severe adverse events were reported. In conclusion, this meta-analysis provides strong evidence supporting the safety and efficacy of carbamazepine as a valuable therapeutic option for the management of trigeminal neuralgia. These results can guide clinicians in making informed decisions regarding the use of carbamazepine and contribute to optimizing treatment strategies for patients with trigeminal neuralgia. Further research is warranted to explore long-term safety and efficacy outcomes, as well as to compare carbamazepine with alternative treatment modalities.

Letter to the editor: A prospective cohort study on perioperative percutaneous balloon compression for trigeminal neuralgia: safety and efficacy analysis

This study evaluated the safety and efficacy of Percutaneous Balloon Compression (PBC) for managing Trigeminal Neuralgia (TN) during the perioperative period in 400 patients. The results indicated no significant difference in postoperative pain relief between male and female patients, although female patients experienced more complications. PBC demonstrated effectiveness regardless of prior treatment, such as PBC, Microvascular Decompression (MVD), or Radiofrequency Thermocoagulation (RFT). Despite its efficacy, PBC has drawbacks, including an increased risk of complications in females and challenges in achieving standardized compression parameters. Compared to other surgical techniques for TN, PBC offers advantages in minimally invasive intervention, but has limitations, particularly in recurrent TN after MVD or RFT. While promising, the lack of standardized protocols and focus on short-term outcomes limits the generalizability of the findings. In conclusion, PBC represents a significant advancement in TN management, providing high initial pain relief rates with minimal invasiveness. However, further research is necessary to standardize procedures, address complications, and evaluate the long-term efficacy for a comprehensive understanding of its role in TN treatment.

A prospective cohort study on perioperative percutaneous balloon compression for trigeminal neuralgia: safety and efficacy analysis

With the recent emergence of percutaneous balloon compression (PBC) as a promising treatment for trigeminal neuralgia (TN), there is a growing need for research on its safety and efficacy. This study was designed to evaluate the safety and efficacy of PBC in the treatment of TN patients during the perioperative period. This study involved a total of 400 TN patients who were selected and treated with PBC at our institution. The clinical data and short-term outcomes were analyzed based on sex, initial PBC treatment for TN, and subsequent PBC treatment for recurrent TN after previous PBC or microvascular decompression (MVD) or radiofrequency thermocoagulation (RFT). No statistically significant difference was found when comparing postoperative pain relief between male and female patients with TN. Nevertheless, female patients were found to be more vulnerable than male patients to abnormal facial sensations (P = 0.001), diplopia (P = 0.015), postoperative headache (P = 0.012), and hyposmia (P = 0.029). Additionally, it was observed that there was no substantial difference in the postoperative pain relief rate between the first-time PBC group and PBC for recurrent TN patients postoperatively following procedures such as PBC, MVD, and RFT. In conclusion, this study has shown that PBC treatment is effective in managing TN in both males and females, regardless of whether the treatment was administered as a primary intervention or following prior surgical procedures such as PBC, MVD, or RFT. Nonetheless, it is noted that the risk of postoperative complications appears to be higher in female patients compared to male patients.

Trigeminal Neuralgia as a Primary Demyelinating Disease: Potential Multimodal Evidence and Remaining Controversies

Trigeminal neuralgia is a heterogeneous disorder with likely multifactorial and complex etiology; however, trigeminal nerve demyelination and injury are observed in almost all patients with trigeminal neuralgia. The current management strategies for trigeminal neuralgia primarily involve anticonvulsants and surgical interventions, neither of which directly address demyelination, the pathological hallmark of trigeminal neuralgia, and treatments targeting demyelination are not available. Demyelination of the trigeminal nerve has been historically considered a secondary effect of vascular compression, and as a result, trigeminal neuralgia is not recognized nor treated as a primary demyelinating disorder. In this article, we review the evolution of our understanding of trigeminal neuralgia and provide evidence to propose its potential categorization, at least in some cases, as a primary demyelinating disease by discussing its course and similarities to multiple sclerosis, the most prevalent central nervous system demyelinating disorder. This proposed categorization may provide a basis in investigating novel treatment modalities beyond the current medical and surgical interventions, emphasizing the need for further research into demyelination of the trigeminal sensory pathway in trigeminal neuralgia. PERSPECTIVE: This article proposes trigeminal neuralgia as a demyelinating disease, supported by histological, clinical, and radiological evidence. Such categorization offers a plausible explanation for controversies surrounding trigeminal neuralgia. This perspective holds potential for future research and developing therapeutics targeting demyelination in the condition.

Progress in study on animal models of trigeminal neuralgia

Trigeminal neuralgia is a manifestation of orofacial neuropathic pain disorder, always deemed to be an insurmountable peak in the field of pain research and treatment. The pain is recurrent, abrupt in onset and termination similar to an electric shock or described as shooting. A poor quality of life has been attributed to trigeminal neuralgia, as the paroxysms of pain may be triggered by innocuous stimuli on the face or inside the oral cavity, such as talking, washing face, chewing and brushing teeth in daily life. The pathogenesis of trigeminal neuralgia has not been fully elucidated, although the microvascular compression in the trigeminal root entry zone is generally considered to be involved in the emergence and progression of the pain disorder. In addition, orofacial neuropathic pain restricted to one or more divisions of the trigeminal nerve might be secondary to peripheral nerve injury. Based on current hypotheses regarding the potential causes, a variety of animal models have been designed to simulate the pathogenesis of trigeminal neuralgia, including models of compression applied to the trigeminal nerve root or trigeminal ganglion, chronic peripheral nerve injury, peripheral inflammatory pain and center-induced pain. However, it has not yet been possible to determine which model can be perfectly employed to explain the mechanisms. The selection of appropriate animal models is of great significance for the study of trigeminal neuralgia. Therefore, it is necessary to discuss the characteristics of the animal models in terms of animal strains, materials, operation methods and behavior observation, in order to gain insight into the research progress in animal models of trigeminal neuralgia. In the future, animal models that closely resemble the features of human trigeminal neuralgia pathogenesis need to be developed, with the aim of making valuable contributions to the relevant basic and translational medical research.

Comparative safety and efficacy of percutaneous radiofrequency thermocoagulation and percutaneous balloon compression in CT-guided and local anesthesia for recurrent trigeminal neuralgia

Background

There are several ways to treat trigeminal neuralgia (TN); however, TN may recur after treatment. Although microvascular decompression (MVD) is considered an effective treatment for trigeminal neuralgia, patients with recurrence may not be willing to undergo craniotomy.

Objective

This study compared the safety and efficacy of percutaneous radiofrequency thermocoagulation and percutaneous balloon compression for treating recurrent trigeminal neuralgia.

Methods

This was a prospective non-randomized controlled study. A total of 52 with recurrent TN were scheduled to undergo surgery in our Hospital from January-June 2021. The patients were classified into percutaneous radiofrequency thermocoagulation (PRT) and percutaneous balloon compression (PBC) groups based on the treatment. All surgeries were performed under computed tomography guidance and local anesthesia. Post-operative complications were also observed. Pain was assessed using the visual analog scale (VAS) and Barrow Neurological Institute (BNI) scale. Efficacy indices were evaluated at 3, 6, 12, and 18 months after surgery.

Results

During follow-up, the efficacy rates of the two methods within 18 months were 76.0 and 88.9%, respectively. All patients had hypoesthesia on the affected side, and no severe complications. Notably, 5 patients (20%) in the PRT group with multiple-branch pain, including the first branch of the trigeminal nerve (V1) pain in the PRT group, received radiofrequency therapy for the supraorbital notch (foramen) after puncture of the foramen ovale. However, multiple pain episodes resolved with only one operation in the PBC group.

Conclusion

CT-guided percutaneous radiofrequency thermocoagulation and percutaneous balloon compression under local anesthesia may be good options for treating recurrent trigeminal neuralgia. Percutaneous balloon compression may be recommended when multiple branches are involved, particularly in cases of V1 neuralgia.

Effectiveness of gamma knife radiosurgery in the management of trigeminal neuralgia associated with multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

Trigeminal neuralgia (TN) is a chronic condition characterized by intense facial pain akin to electric shocks, often associated with the trigeminal nerve. It can be either idiopathic or secondary, with multiple sclerosis (Ms) being a significant contributing factor. Non-responsive patients may opt for minimally invasive procedures, such as gamma knife radiosurgery (GKRS), which offers precise, non-invasive treatment and is frequently chosen as a primary approach. This meta-analysis evaluates the long-term efficacy of GKRS in TN management in Ms patients.

METHODS

We conducted a focused search across various databases. Inclusion criteria encompassed studies with ≥ 30 patients using GKRS for TN in Ms, reporting pertinent clinical outcomes. Primary outcomes assessed GKRS efficacy through Barrow Neurological Institute Pain scores. Secondary outcomes encompassed bothersome numbness, facial numbness, and recurrence. Data analysis employed OpenMeta, random effect models, and odds ratios with 95% confidence intervals. Heterogeneity was assessed using I2 statistics.

RESULTS

Fourteen studies with 752 cases of GKRS for TN were included. Regarding the outcomes, 83% of patients experienced a positive initial pain response, while the overall treatment success rate was 51%. Additionally, 19.6% of patients reported facial numbness, 4.1% experienced bothersome numbness, and 40% faced recurrence. The odds ratio for positive initial pain response was 0.83 (95% CI, 0.76-0.89), while for treatment success, it was 0.51 (95% CI, 0.379-0.639). Facial numbness had an odds ratio of 0.196 (95% CI, 0.130-0.262), bothersome numbness had an odds ratio of 0.041 (95% CI, 0.013-0.069), and recurrence had an odds ratio of 0.403 (95% CI, 0.254-0.551).

CONCLUSIONS

In conclusion, treating trigeminal neuralgia in multiple sclerosis patients remains challenging. GKRS shows promise, but customized treatment approaches tailored to individual patient characteristics are urgently needed to address the unique challenges of this condition.

Comparison of the efficacy in improving trigeminal neuralgia in petroclival meningioma between microsurgery and radiosurgery: a meta-analysis

The purpose of this study was to systematically review studies in the literature to assess the superiority between microsurgery and radiosurgery regarding the efficacy in improving petroclival meningioma (PCM)-related trigeminal neuralgia (TN). PubMed, Embase, Web of Science, and Cochrane clinical trial databases were systematically searched from the inception until December 08, 2022. The overall proportion of patients with improved TN after treatment in all six included studies was 56% (95% confidence interval [CI], 35-76.9%). Higgins I2 statistics showed significant heterogeneity (I2 = 90%). Subgroup analysis showed that the proportion of improved TN was higher in the microsurgery group than that in the radiosurgery group (89%; 95% CI, 81-96.5% vs. 37%, 95% CI, 22-52.7%, respectively, p < 0.01). Subgroup analysis (for studies that documented the number of posttreatment Barrow Neurological Institute scores 1 and 2) revealed that the proportion of pain-free without medication after treatment was higher in the microsurgery group than that in the radiosurgery group (90.7%; 95% CI, 81-99.7% vs. 34.5%, 95% CI, 21.3-47.7.7%, respectively, p < 0.01). Based on the results of this meta-analysis, we concluded that microsurgery is superior to radiosurgery in controlling PCM-related TN.

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.

Percutaneous glycerol rhizolysis of the trigeminal ganglion for the treatment of idiopathic and classic trigeminal neuralgia: Outcomes and complications

BACKGROUND AND PURPOSE

Patients with idiopathic trigeminal neuralgia (TN) with absent arterial contact or venous contact only and classic TN with morphological changes of the trigeminal nerve secondary to venous compression are not routinely recommended microvascular decompression at our institution. In patients with these anatomical subtypes of TN, limited data exists describing the outcomes of percutaneous glycerol rhizolysis (PGR) of the trigeminal ganglion (TG).

METHODS

We performed a retrospective single-center cohort study and analyzed outcomes and complications after PGR of the TG. Clinical outcome after PGR of the TG was assessed via the Barrow Neurological Institute (BNI) Pain Scale.

RESULTS

Forty-five patients underwent a total of 66 PGRs of the TG. At short-term follow-up, 58 procedures (87.9%) resulted in a BNI score of I (i.e., freedom from pain without medication). At a median follow-up of 3.07 years, 18 procedures (27.3%) resulted in a BNI score of I, 12 procedures (18.1%) resulted in BNI score of IIIa, and 36 procedures (54.5%) resulted in a BNI score of IIIb-V. The median length of freedom from pain without medication was 1.5 years. Eighteen procedures (27.3%) caused hypesthesia and two (3.0%) caused paresthesias. There were no serious complications.

CONCLUSION

In patients with these anatomical subtypes of TN there was a high rate of short-term pain relief for the first 1-2 years and thereafter a large proportion of patients experienced pain relapse. In this patient group, PGR of the TG represents a safe procedure that is efficacious in the short term.

A Case Series of Stereotactic Radiosurgery First for Trigeminal Neuralgia: A History of Stereotactic Radiosurgery Does Not Complicate Microvascular Decompression

BACKGROUND AND OBJECTIVES

The influence of prior stereotactic radiosurgery (SRS) on outcomes of subsequent microvascular decompression (MVD) for patients with trigeminal neuralgia (TN) is not well understood. To directly compare pain outcomes in patients undergoing primary MVD vs those undergoing MVD with a history of 1 prior SRS procedure.

METHODS

We retrospectively reviewed all patients undergoing MVD at our institution from 2007 to 2020. Patients were included if they underwent primary MVD or had a history of SRS alone before MVD. Barrow Neurological Institute (BNI) pain scores were assigned at preoperative and immediate postoperative time points and at every follow-up appointment. Evidence of pain recurrence was recorded and compared via Kaplan-Meier analysis. Multivariate Cox proportional hazards regression was used to identify factors associated with worse pain outcomes.

RESULTS

Of patients reviewed, 833 met our inclusion criteria. Thirty-seven patients were in the SRS alone before MVD group, and 796 patients were in the primary MVD group. Both groups demonstrated similar preoperative and immediate postoperative BNI pain scores. There were no significant differences between average BNI at final follow-up between the groups. Multiple sclerosis (hazard ratio (HR) = 1.95), age (HR = 0.99), and female sex (HR = 1.43) independently predicted increased likelihood of pain recurrence on Cox proportional hazards analysis. SRS alone before MVD did not predict increased likelihood of pain recurrence. Furthermore, Kaplan-Meier survival analysis demonstrated no relationship between a history of SRS alone and pain recurrence after MVD ( P = .58).

CONCLUSION

SRS is an effective intervention for TN that may not worsen outcomes for subsequent MVD in patients with TN.

Radiosurgery for classical trigeminal neuralgia: impact of the shot size on clinical outcome

BACKGROUND

This study compares the outcome of patients suffering from medically refractory classical trigeminal neuralgia (TN) after treatment with radiosurgery using two different shot sizes (5- and 6-mm).

METHODS

All patients included in this open, prospective, non-controlled study were treated in a single institution for TN (95 cases in 93 patients) with LINear ACcelerators (LINAC) single-dose radiosurgery using a 5-mm shot (43 cases) or 6-mm shot (52 cases). The target was positioned on the intracisternal part of the trigeminal nerve.

RESULTS

The mean Dmax (D0.035) to the brainstem was higher in the 6-mm group: 12.6 vs 21.3 Gy (p < 0.001). Pain relief was significantly better in the 6-mm group: at 12 and 24 months in the 6-mm group the rate of pain-free patients was 90.2 and 87.8%, respectively vs. 73.6 and 73.6% in the 5-mm group (p = 0.045). At 12 and 24 months post-radiosurgical hypoesthesia was more frequent in the 6-mm group: 47.0 and 58% vs.11.3 and 30.8% in the 5-mm group (p = 0.002). To investigate the effect of cone diameter and the dose to the brainstem on outcomes, patients were stratified into three groups: group 1 = 5-mm shot, (all Dmax < 25 Gy, 43 cases), group 2 = 6-mm shot, Dmax < 25 Gy (32 cases), group 3 = 6-mm shot Dmax > 25 Gy (20 cases). At 12 months the rates of hypoesthesia were 11.3, 33.5 and 76.0%, respectively in groups 1, 2 and 3 (p < 0.001) and the rates of recurrence of pain were 26.4, 16.5 and 5%, respectively, (p = 0.11).

CONCLUSION

LINAC treatment with a 6-mm shot provided excellent control of pain, but increased the rate of trigeminal nerve dysfunction, especially when the maximum dose to the brainstem was higher than 25 Gy.

Large persistent trigeminal artery variant that supplied the subtotal cerebellar hemisphere and caused trigeminal neuralgia, which was diagnosed by magnetic resonance (MR) angiography and MR cisternography

PURPOSE

To describe a case of large persistent trigeminal artery (PTA) variant that caused trigeminal neuralgia, which was diagnosed by magnetic resonance (MR) angiography and MR cisternography.

CASE REPORT

An 82-year-old woman with left trigeminal neuralgia underwent cranial MR imaging, MR angiography and MR cisternography. MR imaging revealed no significant abnormality. MR angiography showed that a relatively large artery arose from the precavernous segment of the left internal carotid artery (ICA) without connection to the basilar artery, which is indicative of a PTA variant. This artery supplied the left cerebellar arteries, except for the rostral branch of the superior cerebellar artery. MR cisternography showed that the inferior surface of the left trigeminal nerve was compressed by the PTA variant. She was treated by microvascular decompression surgery and her symptoms disappeared.

DISCUSSION

According to a meta-analysis, the prevalence of the PTA variants is reported to be 0.2%. The majority of PTA variants are small arteries and are classified as the anterior inferior cerebellar artery type. The present case involved a relatively large artery that supplied large territories of the cerebellar hemisphere. PTA and PTA variants rarely cause trigeminal neuralgia.

CONCLUSION

Using MR angiography and MR cisternography, the author diagnosed a case of large PTA variant that caused trigeminal neuralgia. No similar case has been reported in the relevant English language literature.