Neonatal brachial plexus palsy (NBPP) is frequently associated with internal rotation contractures of the shoulder as a result of muscle imbalance due to muscle fattening and/or fibrosis which favour the internal rotation of the shoulder. Botulinum toxin A (BTX-A) injection in the subscapularis (SC) muscle could weaken the SC and thereby restore muscle balance. The purpose of this study was to assess the effect of intra muscular injection of BTX-A in the SC on the passive external rotation and the need for external rotation surgery in NBPP patients after BTX-A injection.

A prospective comparative study was performed with 93 patients with progressive internal rotation contractures. Al patients underwent an MRI to determine the percentage of the humeral head anterior to the glenoid (PHHA) and glenoid version. Patients younger than 48 months old and with a minimum deformity (PHHA> =35%) or moderate deformity (PHHA< 35%) were included. Patients with a severe deformity or complete posterior dislocation were excluded. Fifteen consecutive patients were injected with BTX-A (2 U/kg body weight, botox^®) at two sites of the SC of the affected shoulder immediately after the MRI under general anesthesia. Seventy eight patients were included as a control group before the new BTX-A treatment was introduced. The passive external rotation was measured pre-MRI and at follow-up. The indication for external rotation surgery was determined after the MRI was performed.

No adverse events were observed. Pre-MRI, the mean passive external rotation in adduction in the BTX-A group was −5° (SE 8°) and in the control group 3° (SE 3°). In the BTX-A group, the mean passive external rotation in adduction increased with 53° (95% CI 31°–74°, p< 0.001) compared to the control group. After stratification the beneficial effect of BTX-A was observed in patients with a minimum deformity (54°, 95% CI 37°–71°, p< 0.001), but this was not significant in patients with a moderate deformity (47°, 95% CI −20°−115°, p=0.13) compared to the control group. The patients in the BTX-A group were less frequently indicated for external rotation surgery compared the control group (27% vs. 89%, p< 0.001). The maximum effect of BTX-A injection was observed at a mean follow-up of 3 months (SE 1). The control group was followed for a mean of 7 months (SE 0.4) to observe the natural history of internal rotation contractures. The groups were comparable regarding type of lesion, primary treatment, age, PHHA, glenoid version and passive external rotation pre-MRI (p 0.09–0.74).

BTX-A injections in the SC of NBPP patients reduce internal rotation contractures. This effect was mainly observed in patients with a minimum glenohumeral deformity. Restoration of muscle balance could prevent further glenohumeral deformation and could prevent external rotation surgery.

Background: Traumatic brachial plexus (BP) injuries may cause loss of elbow flexion. After nerve surgery active elbow flexion often remains insufficient. Muscle strength improvement via cell therapy would be a potential option and could avoid muscle transfer surgery. The primary objective of this pilot study was to assess the safety and feasibility of autologous bone marrow (BM)-derived mononuclear cell (MNC) injection in partly denervated m. biceps brachii of BP patients. Secondary, this study has focused on the myogenic potential of BM-derived MNC by assessing the morphological and functional improvement of the biceps.

Methods: Nine adult BP patients with insufficient force recovery of elbow flexion were included. Three escalating doses (0.9, 4 and 8 * 108) of MNCs were injected in the m. biceps brachii (group A, B and C). In group A, BM was aspirated under local anesthesia (60 ml). In group B and C, BM was aspirated in combination with a muscle tendon transfer (Steindler flexorplasty) under general anesthesia (350 and 650 ml respectively). A muscle biopsy was performed before and 3 months after transplantation. Furthermore, quantitative needle EMG, CT-scan and clinical function was obtained at pre-transplantation and at 3 and 6 months follow-up. The EMG and CT-scan data were blinded during analysis.

Results: No negative side effects were observed. Biopsies showed an increase of 80% in myofiber diameter (P = 0.007), 51% in satellite cells (P = 0.045), 83% in capillary to myofiber ratio (P < 0.001) and a decrease of 51% in fibrosis (P = 0.012). Histological changes were most apparent in group B with an increase of 126% in myofiber diameter (P = 0.019), 100% in capillary to myofiber ratio (P = 0.027), and a decrease of 70% in fibrosis (P = 0.023). EMG demonstrated an increase of 36% in amplitude (P = 0.045), 29% in duration (P = 0.005) and 29% in number of phases of the motor unit potentials (P = 0.002). CT-scan analysis showed a decrease of 48% in mean muscle density (P = 0.009).

Discussion: This study shows that BM-derived MNC transplantation in a partly denervated muscle of traumatic PB patients is safe and feasible. Muscle improvement was observed in muscle biopsies. Furthermore, changes in EMGs and CT-scans were also suggestive for muscle regeneration. The BM dose applied in group B could represent the optimal dose to enhance partly denervated muscles. The results of the present study require confirmation in a placebo-controlled study.