Brachial Plexus Injuries—Where Do We Stand?

When we speak about the current understanding of the surgical management of brachial plexus injuries, we need to look deeply into how far we have moved forward or if we stand still. The brachial plexus injury finds its place in the eighth book of Homer's Iliad between the 12th and 6th centuries BCE.[1] Thorburn, in 1900, described surgical repair for a case of complete rupture of the brachial plexus in a 16-year-old girl and reported poor functional results.[2] Many instances of neurovascular injury in the neck and shoulder region emerged during the First World War. Foerster, in 1929, documented his experience in the surgical repair of 64 cases of brachial plexus injuries.[3] However, his work failed to generate much enthusiasm. This led to a “wait and see” policy in the years between the two World Wars. In 1947, Davis et al published their favorable outcomes in the management of 47 cases of closed and open injuries of the brachial plexus.[4] In 1948, Lurje modernized the neighboring nerve transfers in brachial plexus injuries when a direct repair was impossible. He recommended the transfer of the long thoracic nerve, thoracodorsal nerve, and the triceps branch of the radial nerve to the suprascapular nerve, the musculocutaneous nerve, and the axillary nerve. Soon, Millessi and Narakkas, in the late 1960s and 1970s, popularized the nerve grafting and nerve transfer concepts, respectively, as viable options in proximal nerve injuries.

For elbow flexion, the brachial plexus surgeons preferred and recommended nerve–nerve transfer, such as spinal accessory and intercostal nerves. However, with the advent of the partial ulnar nerve transfer concept by Oberlin et al in 1994, there was a paradigm shift in restoring better elbow flexion.[5] Soon later, Mackinnon recommended dual nerve transfer for the elbow flexion by coapting both biceps and brachialis branches of the musculocutaneous nerve with ulnar and median nerve donor fascicles, respectively.[6] Beyond these nerve transfers, few studies utilized the medial pectoral and the long thoracic nerves as donors and showed promising results. Overall, the ulnar fascicle with or without median nerve fascicles nerve transfers claims superiority in improving elbow flexion. The distal nerve transfer has a short distance between the regenerating motor axons and the target muscle and provides faster recovery than proximal nerve grafting.

The spinal accessory nerve is still the preferred donor for the suprascapular nerve. Brachial plexus surgeons adopt the anterior or posterior approach to this transfer. The posterior approach is beneficial in brachial plexus injuries where the suprascapular nerve might be endangered in cases with displaced clavicles and comminuted scapular neck fractures.[7] Contralateral spinal accessory nerve transfer is also a viable option for the suprascapular nerve in complete brachial plexus injuries. The long head of the triceps or median head triceps branch is the accepted donor nerve for axillary nerve neurotization. Surgeons prefer the anterior deltopectoral, posterior, or axillary recess approach for these transfers. Nevertheless, there is no significant difference between the surgical approaches and the deltoid recovery in these transfers.[8]

For delayed or neglected brachial plexus injuries, free-functioning muscle (gracilis) is the option for elbow flexion. Dual-free functioning muscle transfer using the gracilis can promote elbow flexion/extension and wrist extension/flexion. The key to success lies not only in the meticulous microsurgical technique but also in aggressive and sustained rehabilitation. The prehensile reconstruction in patients with brachial plexus has recently shifted from nerve-crossing procedures to free innervated muscle transfer with multiple nerve crossings.

As brachial plexus surgeons, we have witnessed a reconstructive revival era of distal nerve transfers so far. But today, we lack or have limited scope and options for innovations and significant developments in nerve transfers. This is because of limited opportunities for complex brachial plexus injuries with uncertainty.

Despite these drawbacks, it is vital to understand that we race against time in treating adult traumatic brachial plexus injuries. Irreversible changes occur in motor endplate, and an early exploration as high as 6 weeks in cases suspecting avulsion injuries makes a better outcome. In general, the optimal time of surgical intervention in all traumatic brachial plexus injuries is 1 to 3 months.

The electromyography (EMG) findings with absent voluntary recruitment, discrete, or severely reduced recruitment advocates surgical intervention. The EMG studies localize and grade the motor nerve injury and motor function. Motor nerve testing (nerve conduction study) helps in identifying more distal nerve injuries (at the elbow, wrist, etc.) and underlying or preexisting disorders (neuropathy and myopathy). The sensory nerve amplitudes differentiate between pre- and postganglionic injuries. Neurophysiological testing can establish axonal degeneration but can never definitively demonstrate nerve continuity or disruption. There are no set guidelines for follow-up EMG testing, but 6- to 8-week time intervals are generally chosen. The magnetic resonance neurography of the brachial plexus emerged as a sensitive and specific modality for adult and pediatric brachial plexus injuries. Brachial plexus evaluation must include clinical examination supported by neurophysiological and imaging studies.

With the incorporation of microsurgical techniques, the last few decades have witnessed brilliant results in upper arm type of brachial plexus injuries. Notwithstanding the considerable progress made, we are still far from attaining a complete recovery in all brachial plexus lesions. Management of disabling deafferentation pain and reanimation of hand in total root avulsion injuries continue to pose challenges despite significant refinements and exciting innovations in surgical procedures.

Publication History

Article published online:
02 November 2022

• References

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