Long-term outcomes of microvascular decompression in trigeminal neuralgia: a systematic review

Objective: To assess the long-term results of microvascular decompression (MVD) using autologous muscle for trigeminal neuralgia (TGN).
Methods: We retrospectively reviewed all primary MVD patients for typical classic TGN without previous surgery between 2000 and 2019 at a tertiary supraregional neurosurgery centre. Age, sex, surgical findings, surgical outcomes, complications, and recurrence at 1 year, 5 years, and final follow-up were recorded. Pain relief was measured with the Barrow Neurological Institute (BNI) score. Categorical variables were compared using the Chi-squared test with continuity correction, and Kaplan-Meier curves and Cox regression were used to determine recurrence risk factors.
Results: We analyzed 1035 patients with a median follow-up of 8 years (IQR 5-13 years; range 3-20 years). Immediately after surgery, 893 patients (86.7%) had complete pain relief, 110 (10.3%) had partial pain relief (both groups did not need medication), and 32 (2.9%) had no relief. There were 141 recurrences (13.8%) at a median of 3 years (IQR 2-6 years) after surgery. The proportion of patients without recurrence at 1 year was 97%, 90% at 5 years, 85% at 10 years, 83% at 15 years, and 81% at 20 years. There was no difference in the likelihood of recurrence between patients with complete (114/907 12.6% recurrences) or partial (19/110 17.9% recurrences) pain relief (log-rank p=0.124). The rate of MVD failure was significantly higher in patients with venous compression (N=322, N=16, 5%) than arterial compression (N=14/703, 2%) (chi-squared p=0.015). In a Cox Proportional Hazards model, the hazards of recurrence for venous compression and no immediate postoperative pain relief were 1.62 (95% confidence interval (CI) 1.16-2.27) and 2.65 (95% CI 1.45-4.82), respectively. 124 (12.1%) complications were documented: 44 facial numbness (35.9%), facial nerve palsy (N=37, 29.8%), CSF leak (N=13, 10.5%), and diplopia (N=5, 4%) which resolved in all patients.
Conclusions: MVD with autologous muscle provides long-lasting pain relief in TGN with vascular compression with minimum morbidity and is a viable alternative to synthetic materials.