V2 Trigeminal Neuralgia Research Articles

Microvascular decompression in patients with isolated maxillary division trigeminal neuralgia, with particular attention to venous pathology

The authors have the clinical impression that patients with isolated V2, or maxillary division, trigeminal neuralgia (TN) are most often women of a younger age with atypical pain features and a predominance of venous compression as the pathology. The aim of this study was to evaluate a specific subgroup of patients with V2 TN. Among 120 patients who underwent microvascular decompression (MVD) for TN in 2007, data were available for 114; 6 patients were lost to follow-up. Patients were stratified according to typical (Burchiel Type 1), mixed (Burchiel Type 2a), or atypical (Burchiel Type 2b) TN. A pain-free status without medication was used to determine the efficacy of MVD. All patients were contacted in June 2008 and again in January 2009 at 12-24 months after surgery (median 18.4 months) and asked to rate their response to MVD as excellent (complete pain relief without medication), fair (complete pain relief with medication or some relief with or without medication), or poor (continued pain despite medication; that is, no change from their preoperative baseline pain status. Of 114 patients, 14 (12%) had isolated V2 TN. Among these 14 were 2 typical (14%), 1 mixed (7%), and 11 atypical cases (79%) of TN. Among the remaining 100 cases were 37 typical (37%), 14 mixed (14%), and 49 atypical cases (49%) of TN. In the isolated V2 TN group, all patients were women as compared with 72% of women in the larger group of 100 patients (p = 0.05, chi-square test). The average age in the isolated V2 TN group was 51.2 years (median 48.1 years) versus 54.2 years (median 54.0 years) in the remainder of the group (p = NS, unpaired Student t-test). In the isolated V2 TN group, there was a predominance of atypical pain cases (79%) versus 49% in the remainder of the group, and this finding trended toward statistical significance (p = 0.07, chi-square test). Venous contact or compression (partly or wholly) was noted in 93% of the patients with isolated V2 versus 69% of the remainder of the group (p = 0.13, chi-square test). The likelihood of excellent outcomes in the patients with V2 TN (71%) was compared with that in typical pain cases (79%) among patients in the rest of the group (that is, the bestoutcome group), and no difference was found between the 2 groups (p = 0.8, chi-square test). The authors confirmed that patients with isolated V2 TN were more likely to be female, tended toward an atypical pain classification with venous pathology at surgery, and fared just as well as those presenting with typical pain.

Anatomoradiological landmarks for accuracy of radiofrequency thermorhizotomy in the treatment of trigeminal neuralgia.

The correct positioning of the electrode is of prime importance for effectiveness and selectivity of percutaneous trigeminal radiofrequency thermorhizotomy (RF-TR) for the treatment of trigeminal neuralgia (TN). The aim of our study was to establish some anatomoradiological landmarks for the purpose of accurate placement of the electrode tip in RF-TR. Of 1000 patients who underwent RF-TR, 100 were retrospective and randomly selected and divided into study groups according to postoperative hypoesthesia in the trigeminal nerve divisions. The patients' petroclival angle, petroelectrodal angle, electrode tip, and the petroelectrodal angle/petroclival angle ratio were calculated on lateral cranial x-rays. These measurements were then correlated with the topography of hypoesthesia obtained by the RF-TR to define the anatomoradiological x-ray landmarks corresponding to the divisions of the trigeminal root. The postoperative hypoesthesia groups were correlated with their respective preoperative pain topography to check the accuracy of the thermolesion. In addition, the intraoperatively evoked paresthesia responses and the side effects were evaluated. The results were analyzed using a paired-samples Student's t test, the chi test, and one-way analysis of variance, followed by Bonferroni and Tamhane post hoc tests. All study groups were comparable with respect to age, sex, side effects, electrode tip location, side of TN, and values of petroclival angle. The lowest values of petroelectrodal angle/orbitomeatal electrodal angle and petroelectrodal angle/ petroclival angle were detected in patients with V3 TN, whereas the greatest values were in patients who had TN in all branches of the trigeminal nerve. The greatest height of the electrode was in patients who had TN in all branches, whereas the least height was in patients with V3 TN. When the results were compared with each other, the mean differences were found to be statistically significant between V3 TN patients and the other groups with different P values. There was no statistical difference between the postoperative hypoesthesia data and the preoperative pain topography, which demonstrated evidence of the accuracy of the thermolesion in our series. Our data suggest that the determination of the presented landmarks allows customization to individual patient anatomy and may help the surgeon achieve a more selective effect with a variety of percutaneous procedures for each branch of the trigeminal root.

ANATOMORADIOLOGICAL LANDMARKS FOR ACCURACY OF RADIOFREQUENCY THERMORHIZOTOMY IN THE TREATMENT OF TRIGEMINAL NEURALGIA

Abstract Objective: The correct positioning of the electrode is of prime importance for effectiveness and selectivity of percutaneous trigeminal radiofrequency thermorhizotomy (RF-TR) for the treatment of trigeminal neuralgia (TN). The aim of our study was to establish some anatomoradiological landmarks for the purpose of accurate placement of the electrode tip in RF-TR. Methods: Of 1000 patients who underwent RF-TR, 100 were retrospective and randomly selected and divided into study groups according to postoperative hypoesthesia in the trigeminal nerve divisions. The patients’ petroclival angle, petroelectrodal angle, electrode tip, and the petroelectrodal angle/petroclival angle ratio were calculated on lateral cranial x-rays. These measurements were then correlated with the topography of hypoesthesia obtained by the RF-TR to define the anatomoradiological x-ray landmarks corresponding to the divisions of the trigeminal root. The postoperative hypoesthesia groups were correlated with their respective preoperative pain topography to check the accuracy of the thermolesion. In addition, the intraoperatively evoked paresthesia responses and the side effects were evaluated. The results were analyzed using a paired-samples Student's ttest, the χ2 test, and one-way analysis of variance, followed by Bonferroni and Tamhane post hoc tests. Results: All study groups were comparable with respect to age, sex, side effects, electrode tip location, side of TN, and values of petroclival angle. The lowest values of petroelectrodal angle/orbitomeatal electrodal angle and petroelectrodal angle/ petroclival angle were detected in patients with V3 TN, whereas the greatest values were in patients who had TN in all branches of the trigeminal nerve. The greatest height of the electrode was in patients who had TN in all branches, whereas the least height was in patients with V3TN. When the results were compared with each other, the mean differences were found to be statistically significant between V3 TN patients and the other groups with different Pvalues. There was no statistical difference between the postoperative hypoesthesia data and the preoperative pain topography, which demonstrated evidence of the accuracy of the thermolesion in our series. Conclusion: Our data suggest that the determination of the presented landmarks allows customization to individual patient anatomy and may help the surgeon achieve a more selective effect with a variety of percutaneous procedures for each branch of the trigeminal root.

Surgical treatment of V1 trigeminal neuralgia

Surgical treatment of V1 trigeminal neuralgia