Traumatic Brachial Plexus Injuries Treatment & Management

Formerly, most brachial plexus lesions were treated conservatively. Patients were monitored over 12-18 months for recovery of significant voluntary motor control, and any residual deficit was pronounced permanent. Leffert suggested that after 9-12 months, any residual deficit at the level of the shoulder could be considered permanent. ^[21]  However, recovery of more distal function is sometimes observed more than 1 year after injury. The customary treatments were shoulder fusion, elbow fusion, wrist and finger tenodesis, and transhumeral amputation.

Currently, 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 under consideration. 

In general, current surgical options consist of the following:

• Nerve transfers (neurotization)
• Nerve grafting
• Muscle transfers
• Free muscle transfers
• Neurolysis of scar around the brachial plexus in incomplete lesions

Given that these injuries are very complex and vary widely, patient selection is key. Other preoperative considerations are timing of intervention, which can be critical, and planning of the repair versus reconstructive nature of specific procedures. ^[22]  The timing of and indications for surgical treatment are addressed in more detail below (see Surgical Therapy).

Contraindications for surgical treatment include the following:

• Joint contractures
• Severe edema
• Advanced patient age
• Lack of patient motivation or lack of patient understanding of surgical goals

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.

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 one is waiting for recovery after surgery or waiting for recovery from neurapraxia.

There have been reports in the literature assessing cellular therapy as a potential therapeutic modality after traumatic brachial plexus injuries, suggesting augmented clinical benefits with the combination of cellular therapy and rehabilitation. ^[23]

Surgical options (see below) include nerve (primary) and soft-tissue (secondary) procedures. Primary procedures are reparative in nature; secondary procedures are reconstructive.

The three crucial factors in restoration of upper-arm function after brachial plexus injury are as follows:

• Patient selection
• Timing of surgery
• Prioritization of restoration

Patient selection and evaluation

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

The nerve action potential (NAP) can demonstrate preserved axons or significant regeneration, as well as 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 central nervous system and the peripheral nervous system via a dorsal root ganglion (DRG). Postganglionic lesions do not have SSEPs.

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.

Surgical options

Open injuries, particularly high-velocity gunshot wounds, are treated with debridement and repair (immediate or delayed; see below). External neurolysis should be performed for intraoperative monitoring and electrical studies, or neurolysis alone for nerves in continuity that exhibit an NAP.

Postganglionic neuromas or ruptures may benefit from nerve grafting. From an overall perspective, such grafts include C5 for shoulder abduction, C6 for elbow flexion, and C7 for elbow and wrist extension.

Nerve grafting or nerve transfers (neurotization) may be performed for preganglionic injury (ie, intact cell bodies in DRG) or to reduce reinnervation time. ^[24]  Such procedures, ideally performed within 6 months, reduce time to reinnervation by reducing the distance to the site of the nerve injury.

Sources for transfer include the spinal accessory nerve, intercostal nerves, and the medial pectoral nerve. ^{[25, 26]}  These improve shoulder abduction and external rotation in the common but devastating high plexus injuries (C5, C6). ^[27]  The Oberlin transfer uses a fascicle of a functioning ulnar nerve, but the median nerve or others may also be used in specific cases.

In a systematic review and meta-analysis assessing different donor nerves for nerve transfer to restore elbow flexion after partial or total brachial plexus injury, Kim et al demonstrated that intercostal nerves and phrenic nerves were statistically superior to contralateral C7 in achieving a composite motor score of M3 or better. ^[28]  In patients with upper-trunk injuries, neurotization using ulnar, median, or double-fascicle nerve transfers yielded similarly excellent functional results.

The age of the patient is also an important consideration. The ability of nerve transfers to restore functional strength decreases dramatically with patient age. Therefore, many of the surgical options are reserved for younger patients.

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. ^[29]  This was 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. ^[30]

Ali et al reviewed articles published since 1990 to assess the relative effectiveness of (1) nerve grafting, (2) nerve transfers, and (3) a combination of the two for treatment of brachial plexus injuries. ^[31]  They included in their study only articles that reported on results involving 10 or more cases. They concluded that in upper-trunk brachial plexus injuries in adults, the Oberlin procedure and nerve transfers are more successful in restoring elbow flexion and shoulder abduction, respectively, compared with nerve grafting or combined techniques.

Sousa et al conducted a study comparing the anterior approach with the posterior approach in the transfer of the spinal accessory nerve to the suprascapular nerve in patients with traumatic brachial plexus injuries. ^[32]  Their study included 20 male patients; Narakas' scale was used for assessment of arm abduction and shoulder rotation. The investigators concluded that with regard to external arm rotation, the posterior approach yielded better results.

Timing of surgical intervention

Open injuries from a sharp object may benefit most from immediate exploration and, if possible, direct, end-to-end repair. Unfortunately, blunt-force and avulsion-type injuries are more common. With an open injury from a blunt object, a 3- to 4-week delay in repair, after initial debridement and tagging, allows injured nerve ends to demarcate. Low-velocity gunshots injuries may be neurapraxic and may be observed. High-velocity gunshot injuries warrant early exploration for significant soft-tissue damage.

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 an NAP.

Stretch injuries present the most complex issues. Although timing is controversial for such injuries, a period for spontaneous recovery should generally be allowed. Early surgery may preclude opportunities for spontaneous recovery; however, delaying surgery too long may result in failure of motor end plates and reinnervation. Suspected avulsions may be explored at 3-6 weeks, and generally, failure of adequate reinnervation may be explored at 3-6 months.

A 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.

Prioritization of restoration

Reconstruction details are really a matter of planning; the variety of procedures is large, and reconstruction may have to be staged. Many surgeons prioritize the elbow and then the shoulder for reconstructive procedures. The principal 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. ^[33]

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 for safely maintaining joint motion and suppleness, in conjunction with supports for protection.

Electrical stimulation has been controversial but may at least have psychological benefit. A small study (N = 19) by Pulos et al found that the use of a myoelectric orthosis yielded improved elbow flexion strength, increased function, and reduced pain in the majority of patients with brachial plexus injury and inadequate elbow flexion after observation or surgical reconstruction. ^[34]

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 initiation of treatment with a multidisciplinary approach. ^[35] 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. ^[36] Most surgeons reserve such invasive procedures for long-standing severe pain that is refractory to conservative measures.

Follow-up should be prolonged; neural recovery time is lengthy, with a regeneration rate of 1 mm/day (~1 in./mo). Significant recovery after nerve grafting can take more than 18 months, and maintaining joint mobility, minimizing edema, and treating deafferentation pain during this period can make postoperative care challenging. 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.