Outcomes of Brachial Plexus Neurolysis in 40 Patients With Obstetric Brachial Plexus Injury.

Abstract

Background: Severe traction injury to the brachial plexus (BP) during childbirth can induce the formation of intraneural scar tissue or neuroma in continuity. This can lead to nerve entrapment and demyelination, which inhibit axonal transport to the target muscles. Secondary complications include muscle weakness, contractures, joint deformity, and altered limb growth with prolonged and persistent disability. These patients find difficulty performing activities of daily living. BP neurolysis is one of the multistage reconstructive procedures in patients with obstetric brachial plexus injury (OBPI). The successful outcome of BP neurolysis is reported in patients with OBPI. We report improvements in all Mallet functional movements, including forearm supination angle (the Nath-modified Mallet), in 40 OBPI patients after BP neurolysis.

Methods: Forty OBPI patients (25 female and 15 male with a mean age of 14 years, range 2-25 years; 29 on the right and 11 on the left) underwent BP neurolysis and follow-up evaluations with the lead author and surgeon (RKN). All these patients had undergone multiple previous surgeries, such as primary exploration, Botox, nerve transfer, humeral or forearm osteotomy, wrist tendon transfer, mod Quad, triangle tilt, and biceps tendon lengthening. Patients' pre- and postoperative shoulder functions were evaluated by the surgeon in the clinic and from photos/videos. These functional movements include shoulder abduction, external rotation, hand-to-mouth movement, hand-to-neck movement, and hand-to-spine movement, which score from 1 (no movement) to 5 (normal movement). In addition to the Mallet functional movements, the supination angle (the angle between the midline of the body and the tangential line to the palm with arms straight; neutral = 0, full supination = 90°, full pronation = -90°) was also evaluated and scored using the Nath-modified Mallet before and after BP neurolysis.

Results: Of the 40 patients in this report, 37 (93%) achieved a Mallet grade of 5/5 (n = 23, 58%) or 4/5 (n = 14, 35%) in shoulder abduction after BP neurolysis. The other 3 patients had a Mallet grade of 3/5 (90 degrees) postoperatively in shoulder abduction. There was statistically highly significant improvement after BP neurolysis in shoulder abduction (3.9 ± 0.7 to 4.5 ± 0.6, P < .0001), external rotation (2.9 ± 1.0 to 3.8 ± 1.1, P < .0001), hand-to-mouth (4.2 ± 0.7 to 4.5 ± 0.7, P < .03), hand-to-neck (3.6 ± 0.8 to 4.2 ± 0.8, P < .0001), hand-to-spine (2.9 ± 1.1 to 3.4 ± 1.2, P < .004), forearm supination (3.8 ±1.1 to 4.2 ±1.0, P < .0001), the Nath-modified total Mallet score (21 ± 3.1 to 25 ± 3.3, P < .0001), including supination angle (40.5 ± 48.8 to 56.3 ± 41.6, P < .001). Improvement in the Nath-modified total Mallet functions was weakly associated with follow-up time after BP neurolysis (R = 0.17, P = .0003).

Conclusions: Among the 40 patients, 37 (93%) achieved a Mallet grade of 5/5 or 4/5 in shoulder abduction after surgery with a mean follow-up of 2 years. All upper-limb functional movements improved significantly as BP neurolysis improves axonal transport to the target muscles after surgically removing the external and internal scarring of the upper trunk and its terminal branches. Additionally, neurolysis decompresses the BP from external compression by the surrounding connective tissues and densely scarred scalene muscles. Thus, it can provide these patients with an effective and rapid functional recovery. These children and their parents are pleased with the progress and increased ability to perform their activities of daily living after surgery.