Pain Relief after Surgical Decompression of the Distal Brachial Plexus

Abstract

Background Brachial plexopathy causes pain and loss of function in the affected extremity. Entrapment of the brachial plexus terminal branches within the surrounding connective tissue, or medial brachial fascial compartment, may manifest in debilitating symptoms. Open fasciotomy and external neurolysis of the neurovascular bundle in the medial brachial fascial compartment were performed as a surgical treatment for pain and functional decline in the upper extremity. The aim of this study was to evaluate pain outcomes after surgery in patients diagnosed with brachial plexopathy. Methods We identified 21 patients who met inclusion criteria. Documents dated between 2005 and 2019 were reviewed from electronic medical records. Chart review was conducted to collect data on visual analog scale (VAS) for pain, Semmes-Weinstein monofilament test (SWMT), and Medical Research Council (MRC) scale for muscle strength. Pre- and postoperative data was obtained. A paired sample t -test was used to determine statistical significance of pain outcomes. Results Pain severity in the affected arm was significantly reduced after surgery (pre: 6.4 ± 2.5; post: 2.0 ± 2.5; p < 0.01). Additionally, there was an increased response to SWMT after the procedure. More patients achieved an MRC rating score ≥3 and ≥4 in elbow flexion after surgery. This may be indicative of improved sensory and motor function. Conclusion Open fasciotomy and external neurolysis at the medial brachial fascial compartment is an effective treatment for pain when nerve continuity is preserved. These benefits were evident in patients with a prolonged duration elapsed since injury onset.

Keywords: brachial plexopathy; brachial plexus; compression; entrapment; medial brachial fascial compartment; neuropathy; outcomes; pain; surgery.

Fig. 1

Study flow diagram.

Fig. 2

MRI ( axial view ) of the upper extremity illustrating structures within the MBFC. BAV, brachial artery and veins; BB, biceps brachii; BV, basilica vein; H, humerus; MN, median nerve; MBFC, medial brachial fascial compartment; MRI, magnetic resonance imaging; TB, triceps brachii; UN, ulnar nerve.

Fig. 3

Longitudinal incision along the medial bicipital groove. Subcutaneous tissue is retracted exposing the underlying medial brachial fascial compartment.

Fig. 4

Connective tissue that comprises the MBFC and encloses the neurovascular bundle. MBFC, medial brachial fascial compartment.

Fig. 5

Neurovascular elements are identified and released. Fascia is excised and adhesions are lysed. Nerves and vessels lay loosely in a healthy tissue bed. BA, brachial artery; MN, median nerve; UN, ulnar nerve.

Fig. 6

( A ) Etiology of brachial plexopathy in 21 patients who underwent surgical decompression in our clinic. ( B ) latrogenic causes further described. ( C ) Traumatic mechanisms represented in greater detail.

Fig. 7

Visual analog scale (VAS) for pain scores within the brachium of the affected extremity, before and after surgery. Data shown as mean ± SD. ( n  = 21 patients). * p  < 0.05, ** p  < 0.01. SD, standard deviation.

Fig. 8

Semmes-Weinstein monofilament test (SWMT) for tactile sensation within the finger pulps of the affected extremity, before and after surgery. Data shown as mean ± SD. ( n  = 21 patients). * p  < 0.05, ** p  < 0.01. SD, standard deviation.