Recurrence of trigeminal neuralgia after microvascular decompression: a systematic histopathological evaluation of Teflon granuloma.

Objective: Teflon granuloma is one of the possible causes of recurrence in patients with trigeminal neuralgia (TN) who undergo successful microvascular decompression (MVD). The incidence of Teflon granuloma has been variable and the pathophysiology and mechanisms for recurrence have not been well defined. The aim of this study was to characterize the histological features of Teflon granulomas and correlate their occurrence with clinical and intraoperative findings.

Methods: Histopathological studies were available for 14 specimens from 13 patients over a 15-year period. Histopathological data and clinical findings were analyzed, and correlation analyses were performed.

Results: The mean time until recurrence was 24 months after the index MVD. In 6 instances, the distribution of pain had progressed to an adjacent area, mostly from V2 to V2/V3. All samples showed scar tissue adjacent to the birefringent Teflon filaments, which were embedded between enlarged collagenous fibers. The full configuration of foreign body granuloma with Teflon-adherent giant cells and distinct lymphocytic infiltrates was evident in 10 of 13 instances. Siderophages were found in 4 of 13 instances and microcalcifications occurred in 5 of 13 instances. Notably, the presence of macrophages and siderophages correlated with a longer time to recurrence, suggesting an ongoing inflammatory reaction.

Conclusions: This study highlights differences in histopathological findings over time and their possible relevance in the development of Teflon granuloma. While other factors need to be considered for the clinical manifestations of TN recurrence, according to the histopathological findings described here, preventive measures might be considered.