Use of 5% lidocaine medicated plaster to treat localized neuropathic pain secondary to traumatic injury of peripheral nerves

OBJECTIVE The efficacy of 5% lidocaine medicated plaster (LMP) has previously been demonstrated in post-traumatic localized neuropathic pain. This study evaluated the use of LMP in localized neuropathic pain secondary to traumatic peripheral nerve injury. PATIENTS AND METHODS This prospective observational study enrolled patients with traumatic injuries to peripheral nerves that were accompanied by localized neuropathic pain of more than 3 months duration. Demographic variables, pain intensity (measured using the numeric rating scale; NRS), answers to the Douleur Neuropathique 4 (DN4) questionnaire, and the size of the painful area were recorded. RESULTS Nineteen patients were included, aged (mean ± standard deviation) 41.4 ± 15.7 years. Nerve injuries affected the upper (eight patients) or lower (11 patients) limbs. The mean duration of pain before starting treatment with LMP was 22.6 ± 43.5 months (median 8 months). Mean baseline values included: NRS 6.7 ± 1.6, painful area 17.8 ± 10.4 cm(2) (median 18 cm(2)), and DN4 score 6.7 ± 1.4. The mean duration of treatment with LMP was 19.5 ± 10.0 weeks (median 17.4 weeks). Mean values after treatment were: NRS 2.8 ± 1.5 (≥3 point reduction in 79% of patients, ≥50% reduction in 57.9% of patients) and painful area 2.1 ± 2.3 cm(2) (median 1 cm(2), ≥50% reduction in 94.7% of patients). Functional improvement after treatment was observed in 14/19 patients (73.7%). CONCLUSION LMP effectively treated traumatic injuries of peripheral nerves which presented with chronic localized neuropathic pain, reducing both pain intensity and the size of the painful area.