Risk factors for poor physical and psychological outcomes after traumatic brachial plexus injury: a multicenter retrospective cohort study

Background Traumatic brachial plexus injury (BPI) is associated with upper limb dysfunction, neuropathic pain (NP), and depressive symptoms, but factors linked to these outcomes remain insufficiently defined. Methods This retrospective multicenter cohort study enrolled 327 surgical patients with BPI from 19 regional hospitals. Clinical data were collected from electronic medical records. Follow-up was performed through outpatient visits. Upper limb recovery was evaluated with the Medical Research Council (MRC) muscle strength scale, NP with the Visual Analog Scale (VAS), and depressive symptoms with the 9-item Patient Health Questionnaire (PHQ-9). Multivariable logistic regression was performed using SPSS. Model fit was assessed with the Hosmer-Lemeshow test and the area under the receiver operating characteristic curve (AUC). Results Among 327 patients with unilateral BPI, 259 were male, and the mean age was 34.31 years. Traffic accidents (51.07%) were the main injury mechanism. Most injuries were closed (81.65%), and 81.04% patients had concomitant injuries, most frequently humeral fractures (36.70%). The most common injury pattern was C5-C6 (27.22%). Surgery was performed within 3 months in 195 patients. Over a mean follow-up of 45.78 months, 216 patients achieved muscle strength of M3 or higher. Independent risk factors for poor functional recovery included total BPI (OR = 4.62), surgical delay >6 months (OR = 4.41), and neurotization surgery (OR = 4.38). NP occurred in 189 patients; the main risk factors were surgical delay >6 months (OR = 6.76) and total BPI (OR = 6.22). Depressive symptoms were present in 192 patients; leading risk factors included motorcycle accident (OR = 6.18) and surgical delay >6 months (OR = 3.42). All models showed acceptable calibration and discrimination (AUC ≥ 0.76). Conclusion Total BPI, root avulsion, and surgical delay beyond 6 months were significantly associated with adverse physical and psychological outcomes. Timely surgery and multidisciplinary care, including nerve repair, pain control, and psychological support, may improve recovery in high-risk patients with BPI.