Traumatic Brachial Plexus Injuries 

Updated: Aug 06, 2018
Author: Stefanos F Haddad, MD; Chief Editor: Murali Poduval, MBBS, MS, DNB 

Overview

Background

High-energy trauma to the upper extremity and neck can cause a variety of lesions to the brachial plexus. Most common are traction injuries, in which the head and neck are moved away violently from the ipsilateral shoulder; injuries may also be caused by compression between the clavicle and the first rib, penetrating injuries, or direct blows. Recognition may be delayed by other injuries, particularly to the spinal cord and head.[1, 2]

The treatment of lesions of the brachial plexus has changed from shoulder fusion, elbow bone block, and finger tenodesis following World War II to far greater functional restoration made possible by advances in nerve repair and microsurgery.

The natural history of becoming "one-handed" within 2 years has been replaced by early exploration, neurolysis, nerve grafting, neurotization, and free muscle transfers, as well as tendon transfers, for shoulder and elbow function and for wrist or hand prehension. Advances in diagnostic imaging, nerve transfers, electrophysiologic testing, nerve root repair, nerve rootlet replantation, and free muscle transfers have made this a dynamic but highly specialized field.[3, 4, 5]

Because the topic is a complex one, this article focuses primarily on traction injuries, the most common type in adults. Such injuries usually are catastrophic for the affected individual. Loss of useful function of the upper extremity is common, but early repair and reconstruction are providing far greater restoration than was previously possible a few years ago.

See Football Injuries: Slideshow, a Critical Images slideshow, to help diagnose and treat injuries from a football game that can result in minor to severe complications.

Anatomy

The brachial plexus is formed from the spinal nerves or roots, the coalescence of the ventral (motor) and the dorsal (sensory) rootlets as they pass through the spinal foramen. The dorsal root ganglion contains the cell bodies of the sensory nerves; the cell bodies for the ventral nerves lie within the spinal cord.

Typically, the brachial plexus is formed from C5-T1; in some cases with there is a contribution from C4 (prefixed, 28-62%) or T2 (postfixed, 16-73%). All nerve supply to the upper extremity passes through this plexus. The brachial plexus starts at the scalenes, courses under the clavicle, and ends at the axilla. It is typically composed of five roots, three trunks, six divisions (two from each trunk), three cords, and terminal branches.

The five roots are named according to the level with which they correspond. The C5-7 roots give off branches to form the long thoracic nerve, and the C5 root gives branches to form the dorsal scapular nerve. C5 and C6 gives branches to form the superior trunk, C7 the middle trunk, and C8 and T1 the inferior trunk.

Each of the three trunks has two divisions. One division of each of the trunks forms the posterior cord. The anterior division of the superior trunk and the anterior division of the middle trunk form the lateral cord. The anterior division of the inferior trunk forms the medial cord. The medial, lateral, and posterior cord designations refer to the relations of these structures to the axillary artery.

The superior trunk gives off the suprascapular nerve and a nerve to the subclavius. The posterior cord has the upper and lower subscapular nerves, with the thoracodorsal nerve between them. The lateral pectoral nerve emanates from the lateral cord, and the medial pectoral nerve emanates from the medial cord, but with a connection between the pectoral nerves. The posterior cord then becomes the axillary and radial nerves.

The lateral cord continues as the musculocutaneous nerve; a branch from the medial and lateral cords becomes the median nerve; and a branch from the lateral branch joins the medial cord continuation as the ulnar nerve, after the medial cord gives off the medial brachial cutaneous and the medial antebrachial cutaneous nerves.

The cords and branches are distal to the clavicle; the roots and trunks are proximal. The plexus lies in close proximity to the axillary artery, which exits between the anterior and middle scalenes. Knowledge of this anatomy may allow localization of lesions from the physical examination.

Many different approaches to the brachial plexus have been used. Surgeons' preferences are largely shaped by their training and by the goals of a particular procedure. In any approach, the clavicle can be a barrier to visualization.

Millesi described an approach that uses three anterior incisions with the patient in the supine position.[6] In this approach, a sagittal incision is made on the lower neck and two transverse incisions are made more distally, following skin tension lines. By moving the clavicle and looking at the plexus from both a cephalad and a caudad direction, the operator can visualize the upper, middle, and lower trunks of the brachial plexus and avoid osteotomy of the clavicle. The spinal nerves of the upper plexus can also be visualized with this approach.

Pathophysiology

In traction-type brachial plexus injuries, the head and neck are moved away violently from the ipsilateral shoulder. Upper-plexus injuries (C5 and C6) usually predominate if the arm is at the side because the first rib acts as a fulcrum to direct the traction forces preferentially in line with the upper plexus.

When the arm is moved violently and abducted overhead, the lower elements (C8-T1) typically are injured because the force is directed in line with C7. A lower-plexus lesion predominates when the arm is raised because the coracoid acts as a fulcrum in a similar fashion. Lower-plexus lesions may be more common, in part because of the well-formed transverse radicular ligaments that help resist traction forces at C5, C6, and C7; C8 and T1 lack these ligaments.

Traction forces can result in preganglionic or postganglionic injuries. Preganglionic injuries refer to lesions proximal to the dorsal root ganglion, which is in the spinal canal, and foramen. They may be central or direct from the spinal cord or intradural. Preganglionic lesions do not cause wallerian degeneration or neuroma formation, because the axons remain in continuity with the cell bodies in the dorsal root ganglion. Postganglionic lesions are defined as any lesions distal to the spinal ganglion and are physiologically similar to other peripheral nerve injuries.

Etiology

The common mechanism for traction injuries of the brachial plexus is violent distraction of the entire forequarter from the rest of the body. These injuries usually result from a motorcycle accident or a high-speed motor vehicle accident (MVA). A fall from a significant height may also result in brachial plexus injury, either of the traction type or from a direct blow; penetrating injuries and low- or high-velocity gunshot wounds also are seen.

In traction-type injuries, the crucial prognostic factor is whether the injury is proximal or distal to the dorsal root ganglion (ie, preganglionicor postganglionic). A preganglionic root avulsion means that the cell bodies of the sensory nerves are pulled from the cord, diminishing the possibility of recovery or surgical reconstruction. These are differentiated from distal ruptures—postganglionic stretch injuries—in which cell bodies are still in continuity with their axons.

Epidemiology

Reliable information on the incidence of traumatic brachial plexus injuries is difficult to find; the exact incidence is not known. Goldie and Coates suggested that 450-500 closed supraclavicular injuries occur each year in the United Kingdom.[7] Young males are disproportionately affected, mostly between the ages of 15 and 25 years, as in other types of trauma.

On the basis of 18 years of experience with 1068 patients, Narakas developed his rule of "seven seventies," as follows[8] :

  • Approximately 70% were MVAs
  • Of the MVAs, 70% were motorcycles or bicycles
  • Of the cycle riders, 70% had multiple injuries
  • Of the multiple injuries in cycle riders, 70% were supraclavicular injuries
  • Of the supraclavicular injuries, 70% had at least one root avulsed
  • Of the avulsed roots, 70% were lower C7, C8, T1
  • Of the 70% avulsed roots, 70% of those were associated with chronic pain

Prognosis

Chronic management and residuals

The prognosis for traumatic brachial plexus injuries 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.[9]  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.[10]  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.

Patient Education

Brachial plexus injury significantly influences psychological well-being and daily functioning. As a result, patients experience a high prevalence of posttraumatic stress disorder (PTSD), depression, and suicidal ideation. Patients with brachial plexus injury have a high prevalence of psychological concerns and challenges that will require continued attention throughout treatment.[11]

 

Presentation

History

The index of suspicion for a brachial plexus injury is much higher for severe shoulder girdle injuries, particularly motorcycle and motor vehicle accidents. The mechanism of injury should be considered; these injuries may occur in the setting of polytrauma. The presence of other injuries necessitating sedation indicates that detailed follow-up examination of the upper extremity may be needed.

The patient may present with the following symptoms:

  • Pain, especially of the neck and shoulder - Pain over a nerve is common with rupture, as opposed to lack of percussion tenderness with avulsion
  • Paresthesias and dysesthesias
  • Weakness or heaviness in the extremity
  • Diminished pulses - Vascular injury may accompany traction injury

Physical Examination

The standard advanced trauma life support (ATLS) protocol should be followed. Abrasions to the head, helmet, or tip of the shoulder suggest supraclavicular injury. Ptosis (lid droop), enophthalmos (sinking of the eye into the orbit), anhydrosis (dry eye), and miosis (small pupil) or Horner syndrome suggest a complete lower-plexus lesion (see the image below), in that the sympathic ganglion for T1 is in close proximity to the brachial plexus.

Traumatic brachial plexus injury. Patient has ptos Traumatic brachial plexus injury. Patient has ptosis and myosis of his right eye secondary to complete lower brachial plexus lesion.

Swelling about the shoulder can be dramatic. Diminished or absent pulses suggest vascular injury, and special consideration should be given to rupture of the subclavian vessels. Clavicle fractures often are palpable. Careful inspection and palpation of the axial skeleton may reveal concomitant injuries. Each cervical root should be examined individually for motor and sensory function as soon as circumstances allow.

Some special considerations are warranted for the neurologic examination. Sensory examination is extremely important. Deep pressure sensation may be the only clue to continuity in a nerve with no motor function or other sensation (see Table 1 below). The deep pressure test involves applying full pinch to the nail base and pulling the patient's finger outward. Any burning suggests continuity of the tested nerve. When no burning is elicited, these examination findings are less helpful because a neurapraxia can persist for more than 6 months.

Table 1. Deep Pressure Test (Open Table in a new window)

Location of Deep Pressure Test

Affected Spinal Nerve

Nerve

Affected Cord

Thumb

C6

Median nerve

Lateral cord

Middle finger

C7

Median nerve

Lateral cord

Little finger

C8

Ulnar nerve

Medial cord

Examination of wrist and finger sensation and motion with respect to the median, ulnar, and radial nerves may help locate the lesion within the brachial plexus.

Motor examination is also useful (see Table 2 below). Significant variations occur among the spinal nerves within the cord and account for most of the anomalous patterns of innervation. These variations may make identifying the levels involved challenging. In addition, C4 may contribute a branch to the plexus up to 60% of the time. When C4 makes a significant contribution to the plexus, the plexus is called prefixed. A prefixed cord can explain recovery in the distribution of a nerve root clinically presumed to be avulsed.

Table 2. Guide to Motor Testing (Open Table in a new window)

Cervical Root

Clinically Relevant Gross Motor Function

C5

Shoulder abduction, extension, and external rotation; some elbow flexion

C6

Elbow flexion, forearm pronation and supination, some wrist extension

C7

Diffuse loss of function in the extremity without complete paralysis of a specific muscle group, elbow extension, consistently supplies the latissimus dorsi

C8

Finger extensors, finger flexors, wrist flexors, hand intrinsics

T1

Hand intrinsics

In performing the motor examination, it is important to keep in mind that most individual muscles have contributions from multiple cervical levels (see the image below).

Traumatic brachial plexus injury. Human cadaveric Traumatic brachial plexus injury. Human cadaveric dissection of right brachial plexus shows that clavicle and some soft tissues have been resected. Nerve roots are exiting their respective foramina at right-hand border. Uppermost nerve root observed is C5, with C6, C7, and C8 also visible. Cords of plexus can be observed at left-hand margin. Note axillary artery at bottom.

Elbow flexion and extension determine musculocutaneous and high radial nerve function. Shoulder abduction tests the axillary nerve, which comes off the posterior cord. The posterior cord may also affect deltoid function by the radial nerve. The latissimus dorsi is innervated by the thoracodorsal nerve off the posterior cord and may be tested by palpation of the muscle while the patient coughs.

Pectoralis muscles can be palpated as the patient adducts the arm against resistance (the medial pectoral nerve to the sternal head comes off the medial cord, whereas the lateral pectoral nerve to the clavicular head comes off the lateral cord). The long thoracic nerve innervates the serratus anterior, and the dorsal scapular nerve innervates the rhomboids; thus, winging of the scapula may help localize the injury.

 

Workup

Laboratory Studies

Laboratory studies generally are not helpful for diagnosis of traumatic brachial plexus injury, though they may be indicated in the routine evaluation of any trauma patient. Electrophysiologic studies are crucial in the management of these injuries, but timing (eg, for wallerian degeneration to occur) must be considered.

Imaging Studies

Plain radiography

In anteroposterior (AP) chest radiography, specific attention should be directed to the distance between the spinous processes of the thoracic spine and the scapula. If the radiograph is not malrotated, an increase in this distance as compared with the contralateral side may indicate scapulothoracic dissociation (see the image below).

Traumatic brachial plexus injury. Initial anteropo Traumatic brachial plexus injury. Initial anteroposterior chest radiograph of patient involved in accident with 18-wheeled truck. Clavicle fracture observed on initial chest radiograph was important in signaling need for further evaluation of injury because patient was intubated and unresponsive secondary to closed head injury. Scapulothoracic dissociation was suspected on close review of chest CT scan, and brachial plexus injury was noted once patient became responsive.

AP and axillary lateral views of the shoulder reveal clavicle fractures, most scapular fractures, and most proximal humerus fractures.

Cervical spine radiographs, including AP, lateral, and odontoid, views are useful.

Computed tomography

Adequate plain radiographs, especially of the odontoid and the cervicothoracic junction, may be difficult to obtain. Computed tomography (CT) of the neck can often be obtained in conjunction with the CT evaluation received by many trauma patients. Plain CT is very helpful in evaluating any cervical fractures and should be obtained if fractures are suspected on the basis of plain radiographic findings. Chest CT may reveal subclavian vessel injuries, scapular fractures, humeral fractures, and thoracic spine fractures (see the image below).

Traumatic brachial plexus injury. Plain CT scan ob Traumatic brachial plexus injury. Plain CT scan obtained during initial workup of same patient as in preceding image. Fracture of right scapula is visible, as is right pulmonary contusion and significant periscapular swelling. Scapulothoracic dissociation was suspected on basis of clavicle fracture, scapula fracture, brachial plexus palsy, and high-energy mechanism of injury (ie, accident with 18-wheeled truck). CT scan is oblique; high-quality anteroposterior chest radiograph demonstrating lateral displacement of right scapula was obtained later to confirm diagnosis.

Plain myelography

The most reliable indicator of root avulsion is an absent root shadow on plain myelography.[12] A common sign of a root avulsion is a meningocele at the affected level; hence, myelography may best be delayed for 4 weeks so that any blood clot will not be dislodged by the study and the meningocele can be allowed to form.

CT myelography

The literature is still inconclusive regarding the sensitivity and specificity of CT myelography (CTM), but CTM is being performed more often.[13] CTM is capable of detecting lower concentrations of contrast medium than standard myelography can. Burge stated that CTM may be better able to reveal small meningoceles, but artifact from surrounding soft tissues may be problematic at the lower cervical levels.[14]

Magnetic resonance imaging

Magnetic resonance imaging (MRI) is the current criterion standard for visualizing spinal cord injuries, but reports of its utility in evaluating traumatic lesions of the brachial plexus have been sparse. MRI is the only technique that can be used to visualize the postganglionic brachial plexus. Although the impact of MRI on surgical decision-making is yet to be fully defined, it no doubt will play a larger role in the evaluation of the brachial plexus in the future.

Angiography

Both conventional angiography and magnetic resonance angiography (MRA) are valuable tools in evaluating any suspected vascular disruption.

Other Tests

Sensory nerve action potentials

Sensory nerve action potentials (SNAPs) are very helpful in differentiating preganglionic from postganglionic injuries. If the injury is proximal to the dorsal root ganglion (DRG), no wallerian degeneration occurs, because the sensory axon is intact. Thus, a SNAP observed in a nerve with an anesthetic dermatome confirms a preganglionic lesion. SNAPs are not useful for C5 evaluation, because C5 does not provide a significant contribution to a major peripheral sensory nerve.

Electromyography

In the first week after injury, electromyography (EMG) cannot be used to exclude a complete nerve disruption unless voluntary motor unit action potentials are observed. If no signs of denervation are apparent in a paralyzed muscle by 3 weeks after injury, EMG can be used to confirm neurapraxia.

Somatosensory evoked potentials

Intraoperative somatosensory evoked potentials (SSEPs) are useful in brachial plexus surgery. The presence of SSEPs suggests continuity between the peripheral nervous system and the central nervous system via the DRG. SSEPs are absent in postganglionic or combined pre- and postganglionic lesions.

 

Treatment

Approach Considerations

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 can be considered permanent.[15]  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 considered. 

In general, current surgical options consist of the following:

  • Nerve transfers
  • 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.[16]  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.

Medical Therapy

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.[17]

Surgical Therapy

Surgical options (see below) include nerve (primary) and soft-tissue (secondary) reconstruction. 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.[18]  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.[19, 20]  These improve shoulder abduction and external rotation in the common but devastating high plexus injuries (C5, C6).[21]  The Oberlin transfer uses a fascicle of a functioning ulnar nerve, but the median nerve or others may also be used in specific cases.

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.[22]  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.[23]

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.[24]  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.[25]  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.[26]

Postoperative Care

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 is controversial but may at least have psychological benefit.

Complications

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.[27] 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.[28] Most surgeons reserve such invasive procedures for long-standing severe pain that is refractory to conservative measures.

Long-Term Monitoring

Follow-up should be prolonged; neural recovery time is lengthy, with a regeneration rate of 1 mm/day (~1 in./month). 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.