Neurapraxia in patients with trigeminal neuralgia but no identifiable neurovascular conflict during microvascular decompression: a retrospective analysis of 26 cases

Background Microvascular decompression (MVD) is the first choice in patients with classic trigeminal neuralgia (TGN) that could not be sufficiently controlled by pharmacological treatment. However, neurovascular conflict (NVC) could not be identified during MVD in all patients. To describe the efficacy and safety of treatment with aneurysm clips in these situations. Methods A total of 205 patients underwent MVD for classic TGN at our center from January 1, 2015 to December 31, 2019. In patients without identifiable NVC upon dissection of the entire trigeminal nerve root, neurapraxia was performed using a Yasargil temporary titanium aneurysm clip (force: 90 g) for 40 s (or a total of 60 s if the process must be suspended temporarily due to bradycardia or hypertension). Results A total of 26 patients (median age: 64 years; 15 women) underwent neurapraxia. Five out of the 26 patients received prior MVD but relapsed. Immediate complete pain relief was achieved in all 26 cases. Within a median follow-up of 3 years (range: 1.0–6.0), recurrence was noted in 3 cases (11.5%). Postoperative complications included hemifacial numbness, herpes labialis, masseter weakness; most were transient and dissipated within 3–6 months. Conclusions Neurapraxia using aneurysm clip is safe and effective in patients with classic TGN but no identifiable NVC during MVD. Whether this method could be developed into a standardizable method needs further investigation.

Microvascular decompression for trigeminal neuralgia, long-term follow-up results and assessment of possible prognostic factors: a single-center retrospective cross-sectional cohort study

Aim: Prognostic factors detection and analysis of long-term results of microvascular decompression for trigeminal neuralgia. Materials and methods. 161 cases of trigeminal neuralgia (TN) treatment by MVD technique without preliminary invasive interventions within 10 years were analyzed. Two blocks of information were designed which included objective case data (8 factors) and patient satisfaction survey (5 questions). Follow-up minimal cut-off was 1 year (median 5.8 years). The primary end point is the proportion of pain free patients and BNI (Barrow Neurological Institute) score at last follow-up. The secondary end point is the assessment of possible risk factors of treatment failure: symptoms duration, decompression type, affected nerve branches, neurovascular conflict visible on MRI, different indications for surgery. Logit-regression analysis was carried out. Significance level was set at p<0,01. Results. Among the studied factors as predictors for pain recurrence all but one failed to reach significance threshold. Conflict on MRI (p=0,231), involved nerve branches (p=0,340), indications for surgery (p=0,659), number of involved vessels (p=0,834), achieved decompression type (p=0,157), venous compression (p=0,143), gender (p=0,150), affected side (p=0,934) did not reach the significance level. For symptoms duration p=0,0012. Conclusions. As a result of multifactorial analysis of study results, the only significant prognostic factor for treatment failure (pain recurrence or worsening of obtained result) was symptoms duration at the time of surgery.

Factors Related to the Delayed Cure of Hemifacial Spasm after Microvascular Decompression: An Analysis of 175 Consecutive Patients

Detailed studies assessing the factors related to delayed cure of hemifacial spasm (HFS) after microvascular decompression (MVD) are sparse. We aimed to evaluate the effect of 11 clinical factors on the time until the patient became spasm free after MVD. We enrolled 175 consecutive patients with HFS who underwent MVD between 2012 and 2018. The end point was defined as the time point at which the patient became spasm free based on the outpatient interview. Patients were divided into six groups depending on when they became spasm free after the operation, as follows: <7 days (n = 62), 7 days to 1 month (n = 28), 1 to 3 months (n = 38), 3 to 6 months (n = 25), 6 to 12 months (n = 17), and >12 months (n = 5). The median time to become spasm free after MVD was 30.0 days. Association of 11 factors (age, sex, laterality, number of offending arteries, vertebral artery compression, number of compression sites, compression at root detachment zone, preoperative Botox treatment, indentation of the brain stem on preoperative magnetic resonance image, transposition, and interposition) with spasm-free rate was assessed using the Cox's proportional hazards model. Spasm-free rate curve after MVD for the significant factor was obtained using the Kaplan–Meier method. In univariate and multivariate analyses, nontransposition was significantly related to delayed HFS cure after MVD (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.42, 0.87; p = 0.0068 and HR, 0.60; CI, 0.43, 0.85; p = 0.042, respectively). The spasm-free rate was higher in the transposition than in the nontransposition group (p = 0.0013). As shortening the time until spasm free after MVD improves patients' quality of life, transposition should be recommended. Prediction of spasm-free time could relieve the anxiety of postoperative patients.

Microvascular Decompression by Interposition Method for Treatment of Trigeminal Neuralgia Due to Vertebrobasilar Dolichoectasia: A Retrospective Single-Center Study

Trigeminal neuralgia (TN) due to vertebrobasilar dolichoectasia (VBD) is a rare disease that can be challenging to treat. The objectives of this study are to investigate the characteristics of patients with TN due to VBD and to analyze the efficacy of microvascular decompression (MVD) by the interposition method for treatment of the condition. From 2010 till 2020, the data of 30 patients with TN due to VBD who were treated with MVD by the interposition method were analyzed retrospectively. The characteristics of the patients were compared with those of patients with non-VBD TN (n = 815). Kaplan–Meier survival analysis was performed to determine pain-free survival. The 30 patients (21 males, 9 females; mean age, 63.03 years) accounted for 3.55% of all patients with TN during the study period. In 30 patients, the offending vessel was the basilar artery (BA) in 1 patient, the vertebral artery (VA) in 6 patients, the VA plus the superior cerebellar artery (SCA) in 6 patients, the VA plus the anterior inferior cerebellar artery (AICA) in 12 patients, and the VA+SCA+AICA in 5 patients. Compared to non-VBD TN patients, those with TN due to VBD were significantly more likely to be male, to have TN of the left side, and to have hypertension (all P < 0.001). Mean age at surgery (P = 0.057) and symptom duration (P = 0.308) were comparable between the two groups. All 30 patients had immediate relief of facial pain after MVD and could stop medication. There were no postoperative complications. Over mean follow-up of 76.67 months, 3 patients had recurrence. The mean duration of pain-free survival was 70.77 months. In conclusions, TN due to VBD appears to be more likely in males, in those with hypertension, and to involve the left side. The interposition method performed by experienced and skilled neurosurgeons is a safe and effective treatment for TN due to VBD. Further studies are needed to analyze the associated long-term results and the pain recurrence rate among this special population.

Microvascular decompression for hemifacial spasm involving the vertebral artery

Objective Microvascular decompression (MVD) has become an accepted treatment modality for the vertebral artery (VA)–involved hemifacial spasm (HFS). The aim of this retrospective study was to evaluate clinical and surgical outcomes of HFS patients undergoing MVD and surgical and cranial nerve complications and investigate reasonable transposition procedures for two different anatomic variations of VA. Methods Between January and December 2018, 109 patients underwent first MVD for HFS involving VA at Nanjing Drum Tower Hospital. Based on whether the VA could be moved ventrally at the lower cranial nerves (LCNs) level, patients were assigned to Group A (movable VA, n = 72) or B (unmovable VA, n = 37), and clinical and surgical outcomes and complications on the day of post-surgery and during follow-up were assessed. All patients were followed up ranging from 17 to 24 months with a mean follow-up period of 21 months. Results After a mean follow-up of 21 months, the total cure rate significantly decreased in all patients compared to that achieved on the day of surgery, and Group A patients exhibited a higher cure rate versus Group B (93.1% vs. 75.7%, P = 0.015). Group B patients with unmovable VA revealed both higher incidence of surgical complications (45.9% vs. 15.3%, P = 0.001) and frequency of bilateral VA compression (27% vs. 8.3%, P = 0.009) versus Group A. No significant difference was observed in long-term cranial nerve complications. Conclusions VA-involved HFS can benefit from MVD strategies after preoperative assessment of VA compression. HFS patients with movable VA may receive better long-term efficacy and fewer complications. A Teflon bridge wedged between the distal VA and medulla gives rise to adequate space for decompression surgery.