Prospective PC-interactive pressure algesimetry of post-traumatic neck pain after whiplash injury

Cervical pain is a prominent symptom in both acute whiplash injury and late whiplash syndrome. However, no systematic analysis of post-traumatic pain development covering several weeks has yet been performed in whiplash patients. It was the aim of the present study to analyse the duration and course of post-traumatic muscle pain due to whiplash injury in a prospective follow-up examination with short investigation intervals. A recovery of initially increased muscle pain after whiplash injury within 1 month was hypothesized. Pressure pain of the splenius and trapezius muscles was recorded using PC-interactive pressure algesimetry. Whiplash patients were investigated during the acute injury stage and after 3, 4, and 6 weeks and compared with matched controls. We found significantly increased pressure pain of the splenius and trapezius muscles in the acute stage of whiplash injury. After 4 weeks patients' scores of pain parameters were comparable to those of healthy control subjects. Within the patient group the first changes of pressure pain were observed within 3 (splenius) and 4 weeks (trapezius). For most patients the recovery dynamics lasted 4-6 weeks. A minority of patients did not show any improvement after 6 weeks. The present study shows that the dynamics of pressure pain due to whiplash injury can be quantified by means of PC-interactive pressure algesimetry. Our results confirm the clinical experience that the acute post-traumatic cervical syndrome normally subsides within weeks.