Introduction: Pain relief following microsurgery for trigeminal neuralgia (TN) may be related to multiple factors including pain type(1), degree of neurovascular conflict(2), arterial compression, and location of compression(3). The objective of this study was to construct a predictive scoring system based on clinical and radiographic factors that can preoperatively prognosticate long-term outcomes in TN following surgery.
Methods: 275 patients with Type 1 or Type 2 TN underwent microvascular decompression(MVD) or internal neurolysis(IN) following a preoperative high-resolution MRI. Outcome data was obtained retrospectively by chart review and/or phone follow-up. Characteristics of neurovascular conflict were obtained from preoperative MRI. Factors that resulted in a probability value of <0.05 on univariate logistic regression analyses were entered into a multivariate cox regression analysis in a backward stepwise fashion. For the multivariate analysis, significance at the 0.15 level was used.4 A prognostic system was then devised (see Table 1) with three possible scores (0/1, 2, or 3) and survival analyses were conducted.
Results: Univariate predictors of pain-free survival were pain type(p=0.013), presence of any vessel(p=0.042), and neurovascular compression severity(0.038). Scores of 0/1, 2, and 3 were found to be significantly different in regard to pain-free survival(log rank, p=0.008) (Figure 1). At 5 and 10 years there were 42, 57, and 72% and 42,52, and 58%, pain free survival in groups 0/1, 2, and 3, respectively. TN1 patients with severe neurovascular conflict (score of 3) had the best outcome, which was significantly better that TN1 patients without neurovascular conflict(score of 1)(log rank, p=0.005)(Figure 2). Severe neurovascular conflict is more likely to have arterial compression (99%) (p<0.001).
Conclusions: Pain-free survival of TN patients after microsurgery can be predicted in a step-wise statistically significant fashion, by a simple scoring system based on preoperative clinical and radiographic findings.
Patient Care: This model of predictability is a novel tool which combines easily obtainable data points to quantify preoperative probability of success for Trigeminal neuralgia patients undergoing microsurgical treatment. It may aid in the decision-making process for both patients and clinicians.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Have a greater understanding of the factors that effect outcome following surgical intervention for Trigeminal Neuralgia,
2) Be able to implement this simple scoring system when considering likelyhood of pain-free outcomes in heterogeneous patient populations
3) identify factors which predict a greater likelyhood of successful operative intervention in Trigeminal neuralgia
References: (1)Miller J, Magill S, Acar F, and Burchiel K. Predictors of long-term success after microvascular decompression for trigeminal neuralgia. J Neurosurg. 2009; 110:620-626.
(2)Leal PR, Hermier M, Froment JC, Souza M, Christino-Filho G, and Sindou M. Preoperative demonstration of the neurovascular compression characteristics with special emphasis on the degree of compression, using high-resolution magnetic resonance imagine: A prospective study, with comparison to surgical findings, in 100 consecutive patients who underwent microvascular decompression for trigeminal neuralgia. Acta Neurochir. 2010; 152:817-825.
(3)Jo KW, Kong D-S, Hong K-S, Lee J, and Park K. Long-term prognostic factors for microvascular decompression for trigeminal neuralgia. Journal of Clinical Neuroscience. 2013; 20:440-445.
(4) Kulkarni A, Drake J, Mallucci C, Sgouros S, Roth J, Constantini S. Endoscopic third ventriculostomy in the treatment of childhood hydrocephalus. The Journal of Pediatrics. 2009; 155(2):254-259.