How Does Changing the Time to Surgery Affect the Recurrence of Post-Traumatic Trigeminal Neuropathic Pain

Purpose: The recurrence of post-traumatic trigeminal neuropathic pain (PTTNp) following peripheral microneurosurgery continues to be poorly understood. The objective of this study was to determine if the time from injury to surgery of the trigeminal nerve in patients with PTTNp affected the recurrence of PTTNp following surgery. Patients and Methods: A retrospective cohort of patients with PTTNp prior to trigeminal nerve surgery at a single institute was analyzed for the presence or absence of PTTNp at 6 months postsurgery. The primary predictor was the time from injury to surgical treatment and the primary outcome was the presence or absence of PTTNp using subjective and objective neurosensory testing at 6 months. Four groups were predefined to evaluate the effect of time to surgery: Group 1 (0 to 100 days), Group 2 (101 to 200 days), Group 3 (201 to 300 days), and Group 4 (> 300 days). Repeated measures analysis of variance was used to assess differences in the presence or absence of PTTNp among groups. If a statistical difference was found, a post hoc Tukey-Kramer test was performed. Results: Sixty of 63 eligible patients met inclusion and exclusion criteria with end points at 6 months. The weighted mean PTTNp score in Group 1 was 1.6 ± 0.32, Group 2 was 1.61 ± 0.18, Group 3 was 1.3 ± 0.29, and Group 4 was 1 ± 0.0. There was a statistically significant difference in the primary outcome among the groups based on time from injury to repair (P = .0002). The between-group differences were significant for Group 1 and 3 and 4 and between Group 2 and 3 and 4 (P < .01). Within the 4 cohorts, the percentage of patients with PTTNp before surgery with no neuropathic pain at the 6-month follow-up was 41.6%. However, between the 4 cohorts, when the time to surgery was 200 days or less, the percentage of patients with PTTNp before surgery with no neuropathic pain at the 6-month follow-up was more than 60%. Conclusions: Time from injury to surgery appears to have an effect on the recurrence of PTTNp. Best outcomes are associated with operative interventions within 200 days of the injury.