A clinical study on the pain following brachial plexus injury and its correlative factors

Objective To evaluate the characteristic and correlative factors of pain following traumatic brachial plexus injury and the impact of surgery on pain. Methods This study was a prospective, self-controlled study. Each enrolled patient was asked to respond to the revised short form McGill pain (SF-MPQ-2) and neuropathic pain symptom inventory (NPSI) questionnaire before and after surgery. Multiple factors analysis on pain was carried out and the effect of surgery on pain was evaluated. Results The total number of the study was 100 patients. Both of the SF-MPQ-2 38.33±30.38 and NPSI 15.62±14.84 scores after surgery were significantly lower than those before surgery SF-MPQ-2 50.13±36.55; NPSI 20.24±16.84. The highest score appeared in affective descriptors of the four subscales in SF-MPQ-2 and the score of paresthesia was the highest in the 5 divisions of NPSI, no matter before or after surgery. The postoperative scores of deep pain, evoked pain and paresthesia were significantly lower than the preoperative scores. Preoperative pain was related to whether nerve continuity existed or not (SF-MPQ-2: r=-0.2198, P=0.0280; NPSI: r=-0.2322, P=0.0201). The postoperative SF-MPQ-2 and NPSI scores were significantly lower than preoperative scores in motorcycle accident and weight dropping groups. The SF-MPQ-2 and NPSI scores were the highest in global brachial plexus injury group before and after operation. The SF-MPQ-2 and NPSI scores in global brachial plexus injury group or upper and middle trunks injury group after surgery were significantly lower than those before surgery. The postoperative SF-MPQ-2 and NPSI scores in nerve transfer or neurolysis group were significantly lower than preoperative scores. Conclusion In the study, according to SF-MPQ-2 and NPSI evaluation, affective descriptors and paresthesia accounted for the largest proportion in pain expression. Nerve transfer or neurolysis might have a positive effect on prognosis of neuropathic pain for traumatic brachial plexus injury. Surgery might relieve deep pain and evoked pain and paresthesia. Key words: Brachial plexus; Prospective studies; Neuropathic pain; SF-MPQ-2; NPSI