Abstract
Background and Aims: Neuropathic pain can occur following intentional or unintentional peripheral nerve injury. The purpose of this review was to determine in patients who have post-traumatic trigeminal neuropathic pain or required ablative mandibular operations with transection of the nerve, do those who undergo immediate or early surgical interventions, when compared to those whose nerves are not repaired or delayed, have a decreased or increased risk for resolving neuropathic pain?
Methods: Two single-site and one multi-site retrospective observatory studies of patients who had neuropathic pain prior to operative treatment of the injured nerve and in patients who underwent resection of the mandible for benign or malignant disease with either no repair or immediate repair were analyzed for the presence or absence of neuropathic pain at 6 months post-surgery. The primary predictor variable in the surgical treatment of neuropathic pain pre-existing surgery was the time from injury to repair and the preoperative pain intensity rated by Visual Analogue Scale (VAS). The primary predictor variable in the study of intentional transected nerve was the immediate repair or no repair of the nerve at the time of resection.
Results: There was statistically significant difference in the primary outcome based on time from injury to repair. When the time to surgery was less than 200 days, the percentage of patients with no neuropathic pain was greater than 60%. There was a significant difference in mean VAS between those who had no neuropathic pain (6.4,SD 2.68) and those with recurrence (7.75,SD 1.95). Following mandibular resection there was statistically significant difference between the immediate repair and no repair group. Post-hoc logistic regression modeling showed an inverse relationship between the immediate repair and the incidence of chronic postoperative pain and neuropathic pain with an odd ratio <1.
Conclusions: In patients with neuropathic pain, earlier diagnosis and treatment, including peripheral nerve surgery, should be considered with the best outcomes when operative interventions occur within 200 days of the injury and pain intensity are mild or moderate on VAS scales.
The immediate repair of an intentionally transected trigeminal nerve appears to reduce and possibly eliminate the development of neuropathic and chronic postoperative pain compared to avoiding nerve repair.