Traumatic Brachial Plexus Injuries Treatment & Management

Nonoperative treatment of brachial plexus lesions is complex and may best be addressed by an integrated multidisciplinary team that includes a skilled orthotist, occupational therapists, physical therapists, and physicians. Bracing often plays a role in preventing contractures while waiting for recovery after surgery or while waiting for recovery from neurapraxia.

Operative care of the brachial plexus is a highly specialized field that is limited to relatively few tertiary care centers. Wide variation exists in how these injuries are addressed surgically. The availability of subspecialists with experience in the operative management of these lesions is critical if operative management is considered.

In general, the surgical options consist of nerve transfers, nerve grafting, muscle transfers, free muscle transfers, and neurolysis of scar around the brachial plexus in incomplete lesions. Advances in the field are likely to create more surgical options in the future. For example, Carlstedt obtained promising initial results with the repair of preganglionic lesions by replanting nerve rootlets directly into the spinal cord.^[17] This is a dramatic advance because preganglionic lesions were previously thought to be irreparable. Further, end-to-side radial sensory to median nerve transfer has been reported to improve sensation and to relieve pain in C5 and C6 nerve root avulsion.^[18]

Patient selection is key, as these injuries are very complex and vary widely. Other preoperative considerations are timing of intervention, which can be critical, and planning of the repair versus reconstructive nature of specific procedures.^[19]

Initial evaluation centers on examination, particularly sensation and remaining motor function, but electrodiagnostic studies and imaging are integral to planning for any proposed procedure.

Physical therapy may be important in the prevention of contractures during the period of preoperative observation. However, surgery may proceed without observation if examination and imaging demonstrate the absence of potential for spontaneous recovery.

Immediate exploration with possible end-to-end repair may be indicated in some cases of open injury caused by a sharp object. Unfortunately, blunt-force and avulsion-type injuries are more common; if such an injury is open, nerves may be tagged at debridement, but call for 3-4 weeks for demarcation for delayed repair.

Although timing is controversial for stretch injuries, a period for spontaneous recovery should be allowed. However, too lengthy a delay may result in motor end-plate failure, which typically occurs at 3-6 months.

Reconstruction details are really a matter of planning, as the variety of procedures is large and reconstruction may need to be staged. Many surgeon prioritize the elbow and then the shoulder for reconstructive procedures. The principle considerations are the root level involved and the specific deficits, particularly hand sensibility, wrist extension, finger flexion, wrist flexion, finger extension, and intrinsic function of the hand.^[20]

Examples of nerve grafting include cable grafts of sural nerve with C5 to target shoulder abduction, C6 for elbow flexion, and C7 for elbow and wrist extension.

Primary procedures are repair procedures; secondary procedures are reconstructive.

Open injuries, particularly high-velocity gunshot wounds, call for debridement and immediate repair when possible, or tagging of nerves for delayed repair. External neurolysis should be performed for intraoperative monitoring and electrical studies, or neurolysis alone for nerves in continuity that exhibit a nerve action potential (NAP). The NAP can demonstrate preserved axons or significant regeneration, and potential for further recovery; a neurapraxic lesion shows no NAP, as opposed to axonometric lesions (positive for NAP). Otherwise (no intraoperative NAP) nerve grafting can be done for postganglionic neuromas or neural ruptures.

Somatosensory evoked potentials (SSEPs) demonstrate continuity between the CNS and the peripheral nervous system via a dorsal root ganglion (DRG). Postganglionic lesions do not have SSEPs.

Nerve grafting or nerve transfers (neurotization) may be performed for preganglionic injury (ie, intact cell bodies in DRG) or to reduce reinnervation time, usually within 6 months of the trauma.

Expectations after surgery are not for immediate recovery, but instead for a slow process requiring significant patient and family education and involvement. Physical therapy is critical to safely maintain joint motion and suppleness, as well as supports for protection. Electrical stimulation is controversial but may at least have psychological benefit.

Follow-up should be prolonged, as neural recovery time is lengthy, with a regeneration rate of 1 mm per day (1 inch per month). Tendon and free muscle transfers as well as arthrodeses may be critical to restoring some function; even marginal improvements may be functionally significant.

Physical therapy and bracing often are used over the prolonged postoperative period to prevent contractures, to keep joints supple after surgery, and to reinforce the need for patience from patient and family.

Contractures related to certain types of incisions have been reported. In some exposures, the spinal accessory nerve is at risk and should be protected. More specific complications are variable and depend on the exact type of procedure performed.

Deafferentation pain can be one of the most difficult problems for the clinician to treat after brachial plexus injuries. This pain syndrome may occur after surgical repair or with conservative treatment of brachial plexus lesions. When the nerve roots are avulsed in preganglionic lesions, the cells in the dorsal column are robbed of their nerve supply. Shortly after the injury (days to weeks), spontaneous signals are generated in these cells. These spontaneous signals can result in intractable pain for the patient. Patients often report severe burning in the extremity, and they may describe the pain as shooting or crushing. Typically, the pain is severe and has a paroxysmal component.

Treatment of deafferentation pain begins with conservative measures. A pain management team should be involved early, and admission is often helpful to allow for initiation of treatment with a multidisciplinary approach.^[21] Antidepressants, anticonvulsants, and narcotics all may have a role, and treatments must be customized to the character of the pain and to the patient. As with other types of neurogenic pain, gabapentin has met with some success in the treatment of deafferentation pain.

Transcutaneous nerve stimulation (TNS) can be considered. TNS may work by preventing the cells in the dorsal column from sending abnormal signals proximally. TNS must be used for a prolonged period, and maximum benefit from the device may not occur for several months. For a total brachial plexus lesion (C5-T1), the stimulators are placed on the front of the chest (C3-C4 dermatome) and on the inner arm (T2 dermatome).

Acupuncture, hypnosis, biofeedback, and various desensitization protocols have been tried with mixed results.

Advances in surgical technique have renewed interest in surgical procedures to disrupt the signals generated in the dorsal reentry zone (DREZ) of the dorsal columns. Thomas and Sheehy documented good pain reduction (75% relief) in about half of the patients in their series.^[22] Most surgeons reserve such invasive procedures for long-standing severe pain that is refractory to conservative measures.

The prognosis is highly variable. It depends not only on the nature of the injury but also on the age of the patient and the type of procedure performed. Doi et al reported achieving reliable grasping of the hand and voluntary control of the shoulder and elbow after complete avulsion of the brachial plexus.^[23] They achieved these impressive results using a double free muscle transfer technique. Kandenwein et al presented 134 cases that were treated surgically for traumatic brachial plexus lesions.^[24] In this group, the percentage of patients with grade 3 or better motor strength progressed from 2% preoperatively to 52% postoperatively, an enormous improvement over historical results; graft reconstruction performed better than neurotization.

Clear consensus regarding surgical timing and surgical indications is lacking. However, sural nerve grafting has been shown to be better than neurotization, and surgery between 3 and 6 months has become more common and preferred, with better outcomes. There is some difficulty in obtaining a significant series of comparable patients. More research is needed to demonstrate the efficacy of most of the procedures currently available.

The future may bring further advances in nerve rootlet replantation for preganglionic injuries and in free muscle transfer techniques. Research into growth factors that promote nerve regeneration may make nerve grafting and transfers more appealing in the future.