Reconstruction of the Suprascapular Nerve in Brachial Plexus Birth Injury

Abstract

Background: Shoulder external rotation recovery in brachial plexus birth injury is often limited. Nerve grafting to the suprascapular nerve and transfer of the spinal accessory nerve to the suprascapular nerve are commonly performed to restore shoulder external rotation, but the optimal surgical technique has not been clearly demonstrated. We investigated whether there was a difference between nerve grafting and nerve transfer in terms of shoulder external rotation recovery or secondary shoulder procedures. Methods: This is a multicenter, retrospective cohort study of 145 infants with brachial plexus birth injury who underwent reconstruction with nerve grafting to the suprascapular nerve (n = 59) or spinal accessory nerve to suprascapular nerve transfer (n = 86) with a minimum follow-up of 18 months (median, 25.7 months [interquartile range, 22.0, 31.2 months]). The primary outcome was the Active Movement Scale (AMS) score for shoulder external rotation at 18 to 36 months. The secondary outcome was secondary shoulder surgery. Two-sample Wilcoxon and t tests were used to analyze continuous variables, and the Fisher exact test was used to analyze categorical variables. The Kaplan-Meier method was used to estimate the cumulative risk of subsequent shoulder procedures, and the proportional hazards model was used to estimate hazard ratios (HRs). Results: The grafting and transfer groups were similar in Narakas type, preoperative AMS scores, and shoulder subluxation. The mean postoperative shoulder external rotation AMS scores were 2.70 in the grafting group and 3.21 in the transfer group, with no difference in shoulder external rotation recovery between the groups (difference, 0.51 [95% confidence interval (CI), −0.31 to 1.33]). A greater proportion of the transfer group (24%) achieved an AMS score of >5 for shoulder external rotation compared with the grafting group (5%) (odds ratio, 5.9 [95% CI, 1.3 to 27.4]). Forty percent of the transfer group underwent a secondary shoulder surgical procedure compared with 53% of the grafting group; this was a significantly lower subsequent surgery rate (HR, 0.58 [95% CI, 0.35 to 0.95]). Conclusions: Shoulder external rotation recovery in brachial plexus birth injury remains disappointing regardless of surgical technique, with a mean postoperative AMS score of 3, 17% of infants achieving an AMS score of >5, and a high frequency of secondary shoulder procedures in this study. Spinal accessory nerve to suprascapular nerve transfers were associated with a higher proportion of infants achieving functional shoulder external rotation (AMS score of >5) and fewer secondary shoulder procedures. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Triceps to teres minor motor nerve transfer to restore glenohumeral external rotation after neonatal brachial plexus injury

“…The unexpected finding of the ineffectiveness of this additional nerve transfer restoring aGHER during primary plexus reconstruction confirms prior reports describing difficulty restoring aGHER in infants. It also is consistent with the low 5%–25% of patients achieving true glenohumeral external rotation after microsurgical brachial plexus reconstruction (Manske et al, 2020; Pondaag et al, 2005). In addition, only 40% of children with NBPI who recover antigravity elbow flexion between the fourth and fifth month of age also recover spontaneous active shoulder external rotation (Paavilainen, 2015).…”

“…It also is consistent with the low 5%-25% of patients achieving true glenohumeral external rotation after microsurgical brachial plexus reconstruction (Manske et al, 2020;Pondaag et al, 2005). In addition, only 40% of children with NBPI who recover antigravity elbow flexion between the fourth and fifth month of age also recover spontaneous active shoulder external rotation (Paavilainen, 2015).…”

“…Attaining active glenohumeral external rotation (aGHER) following primary reconstruction or spontaneous recovery is infrequent in patients with neonatal brachial plexus palsy (NBPI) (Manske et al, 2020; Soldado, 2020). Reconstruction with tendon transfers result in mediocre outcomes and further glenohumeral contractures (Greenhill et al, 2018).…”

Brachial Plexus Birth Injuries

“…A trend toward worse Mallet scores and increased rates of secondary shoulder procedures with nerve grafting was reported by the TOBI Study Group 68 , which retrospectively reviewed 145 infants with BPBI who underwent reconstruction with either nerve grafting or nerve transfer. While the average AMS score for shoulder external rotation was similar between the 2 groups, 24% of the patients who underwent nerve transfer achieved a score of 6 to 7 compared with 5% of patients in the nerve-grafting group 69 . Heterogeneity among patients, length of follow-up, and patient factors make direct comparisons difficult.…”

Recent Advances in the Treatment of Brachial Plexus Birth Injury

“…Three years after SAN-to-SSN transfer, only 14% of BPBI children have external rotation greater than 20 degrees beyond the sagittal plane, 59 and several studies have independently demonstrated a mean external rotation AMS score of only 3 after SAN-to-SSN transfer. 58,61,63,64 The suboptimal results in previous reports may be confounded by unrecognized glenohumeral abnormality. More recently, selective transfer of the SAN to the infraspinatus branch of the SSN has been described in patients with congruent glenohumeral joints with encouraging results: a preliminary series showed that 86% of patients had active external rotation greater than 20 degrees beyond the sagittal plane.…”