Functional outcome predictors after spinal accessory nerve to suprascapular nerve transfer for restoration of shoulder abduction in traumatic brachial plexus injuries in adults: the effect of time from injury to surgery

Shoulder abduction is crucial for daily activities, and its restoration is one of the surgical priorities. We evaluated the predictive factors of shoulder abduction functional outcome after spinal accessory nerve (SAN) to suprascapular nerve (SSN) transfer, with special emphasis on the effect of time from injury to the surgery, in the treatment of traumatic brachial plexus injuries.

This cohort included adult patients who underwent SAN-to-SSN transfer with a preoperative Medical Research Council strength grade 0 and a follow-up of minimum 18 months. The primary outcome was shoulder abduction function (bad, < 30°; good, 30°–60°; or excellent, > 60°). Demographics, trauma characteristics, time lapse between injury and surgery, concomitant axillary nerve reconstruction, and surgery duration were registered. Ordinal logistic regression was used to identify predictors of functional outcomes.

The records of 83 patients (86.7% men, mean age 28.8 ± 9.8 years) were analysed. Mean body mass index was 24.1 ± 3.7 kg/m², and 43.1% were overweight/obese. Motorcycle crashes were the most common trauma mechanism (88.0%). Excellent, good, and bad outcomes were achieved by 20.4%, 38.6%, and 41.0%, respectively. Older patients tended to have worse outcomes (p = 0.074), as well as left-sided lesions (p = 0.015) or those contralateral to manual dominance (p = 0.057). The longer the interval between injury and surgery the worse the outcome: excellent, 5.5 (4.3–7.1); good, 6.9 (5.9–8.7); and bad, 8.2 (5.7–10.1) months (p = 0.018). After multivariable analysis, longer time interval predicted lower odds of better outcomes (OR 0.823, 95% CI 0.699–0.970, p = 0.020; 17.7% lower odds of good or excellent outcome for each additional month). The odd of good or excellent outcomes was also associated with axillary nerve reconstruction (OR 2.767, 95% CI 1.016–7.536, p = 0.046), but not with age or lesion laterality.

Excellent or good functional outcomes for shoulder abduction were achieved by almost sixty percent of adults who underwent SAN-to-SSN transfer for reconstruction of traumatic brachial plexus injuries, associated or not with axillary nerve reconstruction strategies. Longer delays from injury to surgery predicted worse outcomes, and the best time frame seemed to be less than 6 months.