Birth-Related (Obstetrical) Brachial Plexus Injuries Treatment & Management

Updated: May 10, 2018
  • Author: Alison Snyder-Warwick, MD; Chief Editor: Jeffrey D Thomson, MD  more...
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Treatment

Approach Considerations

Most infants with birth-related brachial plexus palsy (BRBPP) demonstrate spontaneous improvement in upper-extremity function and do not require surgical management. Spontaneous complete recovery rates have been reported to be as high as 93% by age 4 months. [75]  Recovery rates and extent depend on the injury type and severity. Mild injuries with rapid recovery clearly do not require surgery. Similarly, injuries involving a flail upper limb and Horner syndrome require operative management.

Discerning the conditions between these two extremes that would benefit from operative management is more challenging. Historically, absence of elbow flexion by age 3-4 months has been used as a predictor of benefit from operative management. Poor shoulder function at age 5 years and increased need for secondary procedures were noted by Gilbert and Tassin in infants who had no biceps function at age 3 months and received no surgery. [76, 77]

The timing for surgical intervention has since been debated in the literature. [78, 40, 79]  When absence of elbow flexion alone was used to predict outcome, Michelow et al [23]  reported poor recovery was incorrectly reported 12% of the time. When evaluation of elbow, wrist, finger, and thumb extension were added to assessment of elbow flexion at age 3 months, poor recovery was incorrectly predicted only 5.2% of the time.

The Toronto Test Score consists of the sum of converted scores from the Active Movement Scale (see Table in Clinical) for these five movements at age 3 months. Operative management is indicated for a test score of less than 3.5. Fisher et al [80]  reviewed 209 patients with OBPP managed over a 4-year period at the Hospital for Sick Children. Groups were divided by presence or absence of elbow flexion at age 3 months, as well as surgical or nonsurgical management. At 3-year follow-up, no differences in upper extremity function were noted among the groups, indicating that elbow flexion alone is a poor predictor of functional prognosis and need for surgical intervention.

Clarke et al at the Hospital for Sick Children developed a general algorithm that includes motor assessment at birth and then age 3, 6, and 9 months. [81]  Patients with a flail arm and Horner syndrome may proceed to early surgical management. Horner syndrome is a poor prognostic sign. [82]

The Toronto Test Score is performed at age 3 months. A score of less than 3.5 predicts poor spontaneous recovery and is an indication for surgical management. For infants who scored greater than 3.5, the motor examination is again completed at age 6 months. Failure to improve from low scores on the Active Movement Scale at age 6 months may indicate a need for surgical intervention.

At age 9 months, the child again undergoes motor evaluation and assessment with the “cookie test,” which involves placing a lightweight cookie in the affected upper extremity with the humerus adducted against the chest wall. The child passes the test if he or she is able to flex the elbow sufficiently to reach the cookie to the mouth without flexing the neck more than 45°. In cases of a passed cookie test, nonoperative management is usually recommended. Operative intervention for C5-6 neuroma excision and sural nerve grafting has been suggested for patients who have elbow flexion at 9 months but who have deficits in shoulder motion or forearm supination. [81, 83]

There is a small subset of patients who, despite passing these previous milestones, may benefit from primary nerve surgery to treat poor shoulder function, particularly external rotation. [81]

It should be noted that no single algorithm is universally applicable, and management decisions must be achieved based on individual circumstances and performance over time.

Brachial plexus reconstructions are complex, lengthy procedures that require skill, appropriate equipment, and a well-prepared team. The patient’s overall health status must be included in the consideration for operative management. The patient must be sufficiently healthy for a prolonged surgical procedure. The brachial plexus is in the vicinity of critical structures such as the great vessels and thoracic cavity. Systemic conditions such as coagulopathies may be contraindications for surgery.

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Medical Therapy

Physical therapy is used to maintain passive range of motion (ROM) of the affected joints. Some believe that in patients with BRBPP, transcutaneous electrical nerve stimulation (TENS) is useful in waking up muscles that have been successfully reinnervated over a period of time. [84] However, no scientific studies support this conclusion, and the authors do not routinely employ this modality.

Glenohumeral dysplasia (GHD) with shoulder instability (dislocation or subluxation) may be managed with chemodenervation of internal shoulder rotators, closed reduction, and shoulder spica casting. [85]  

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Surgical Therapy

Once the need for operative intervention has been determined, many reconstructive options are available, depending on the intraoperative findings, including the type of neural lesion encountered, the resulting neural gap, and the amount of available neural donor tissues. Surgical treatment involves brachial plexus exploration, neuroma excision, and nerve grafting or nerve transfer.

Preparation for surgery

Given the complexity and length involved with brachial plexus reconstruction procedures, appropriate preoperative planning can improve efficiency and outcomes. Safety measures, such as suturing the nasotracheal tube to the nasal septum and placing a clear plastic drape over the patient’s face, may prevent disastrous and avoidable airway complications. The patient should be appropriately positioned, with all pressure points effectively padded and protected. Throughout the process, communication among all caregivers is essential to minimize complications.

Operative details

Neuroma excision has been shown to have superior long-term results compared with neurolysis alone in children with birth-related brachial plexus lesions. Neurolysis alone for the surgical management of neuroma-in-continuity provides functional improvements at 12-month follow-up for patients with upper-plexus, but not total-plexus, lesions. [86]  After neuroma excision and interpositional nerve grafting, patients with BRBPP regain their preoperative functional levels by 3-6 months postoperatively, [87]  indicating no downgrade of function for patients selected as operative candidates via the previously outlined algorithm.

In a long-term comparison of 108 patients receiving either neurolysis alone or neuroma excision and interpositional grafting, patients with upper-plexus lesions who received only neurolysis had no functional improvements 4 years postoperatively, whereas those with upper-plexus lesions receiving neuroma resection and grafting achieved significant functional gains in seven tested movements. [88] In the same study, patients with total-plexus lesions treated with neuroma resection and grafting demonstrated significant functional improvements in 11 of 15 tested movements at 4-year follow-up, whereas the corresponding group treated with neurolysis alone showed no significant functional improvements.

Because neuroma resection and grafting yields improved outcomes in BRBPP patients requiring surgical management, sural nerve grafts can be harvested as the first stage of the procedure. This sequence allows initial prone patient positioning to facilitate sural nerve graft harvest, followed by supine positioning for brachial plexus exposure and reconstruction. Sural nerve harvest for graft material results in minimal donor-site morbidity but does create a permanent insensate patch at the lateral foot, which, though measurable, often goes unnoticed by patients. [89]  When the sural nerve is harvested proximally, from its branch point from the tibial nerve, up to 13-15 cm per leg may be obtained from a 10-kg infant.

Many approaches to brachial plexus exposure may be used, but the authors typically use a supraclavicular approach with a V-shaped incision coursing along the posterior border of the sternocleidomastoid (SCM) and the superior edge of the clavicle. As dissection proceeds to expose the plexus, the clavicular head of the SCM and the external jugular vein may have to be divided. The supraclavicular sensory nerves may be required as additional graft material and therefore should be divided distally during the exposure to preserve length. The transverse cervical artery and omohyoid are also divided.

Once exposed, the fat pad of Brown is swept laterally to expose the brachial plexus. The suprascapular vessels are divided to increase exposure of the brachial plexus neuroma. The phrenic nerve, coursing from lateral to medial, is carefully dissected away from the neuroma. Each of the roots of the brachial plexus is then systematically identified as the neuroma is dissected to determine the level and nature of the lesion. The C4 root is located as a landmark for identifying the C5 root by following the supraclavicular nerves proximally. Dissection of the neuroma proceeds in a cranial-to-caudal direction. An empty foramen suggests root avulsion.

Once the proximal extent of the neuroma is identified, dissection proceeds distally to identify healthy nerve. The nerve trunks are identified and dissected. The dorsal scapular artery, located between either the upper and middle trunks or the middle and lower trunks, requires division for adequate plexus visualization. Infraclavicular exposure can usually be achieved with inferior traction on the clavicle rather than clavicular resection. Care should be taken to avoid injury to the subclavian artery during dissection of the C8 and T1 roots. The T1 root lies adjacent to the parietal pleura and can be adherent depending on the extent of the neuroma.

A saline pool test should be performed after dissection is completed to assess pleural integrity. The neuroma should be dissected in its entirety. The nerve roots are stimulated to ascertain functional upper extremity results.

Once the neuroma is completely exposed, it is divided in its midportion. Distally, nerves are divided at healthy, soft-appearing nerve, distal to the neuroma. Distal neural ends are sent to pathology as frozen sections for histologic examination. Proximally, nerves should also be transected in healthy regions and samples sent for frozen section. The frozen sections are then reviewed with a neuropathologist to ensure absence of fibrosis or scarring and the presence of a normal fascicular pattern to ensure reconstruction outside of the zone of injury. Management should incorporate information from preoperative imaging, histologic appearance, and intraoperative appearance and stimulation.

Once the neuroma is adequately resected, the resulting nerve gaps should be measured. Reconstruction may consist of a combination of nerve grafts and transfers, if necessary, depending on the size of the neural gaps and the amount of nerve graft available. Priority is given to reconstruction of hand function, followed by the elbow and shoulder.

Anatomic reconstructions, or grafts from the intended target to the original root, are performed whenever possible. Cable grafts are performed with the amount of available graft. Additional graft material may be obtained from the cervical plexus if required. All grafts are reversed to minimize axonal dropoff. Neural coaptations are performed with fibrin glue with the use of the operating microscope.

Nerve transfers allow reconstruction of a nerve from a different nerve source and are useful in cases of root avulsion, late presentation, or isolated deficits. Transfers also allow reconstruction of specific motor or sensory deficits with a single nerve coaptation and can sometimes be performed in closer proximity to the target function to allow more rapid target innervation. [90]  The International Federation of Societies for Surgery of the Hand noted limitations in the literature that prevent direct comparisons of nerve grafting and nerve transfer and cautioned against overreliance on nerve transfers for patients with severe BRBPP. [91]

The spinal accessory–to–suprascapular nerve transfer is commonly performed in cases of BRBPP for restoration of supraspinatus and infraspinatus muscle function. [92, 93]  This transfer can be performed from either an anterior or a posterior approach, [94, 95]  and the posterior approach allows simultaneous release of the suprascapular ligament, which is a known compression site of the suprascapular nerve.

Reconstruction of biceps function can be performed via the Oberlin transfer, which consists of transfer of a redundant branch supplying the flexor carpi ulnar muscle to the biceps branch of the musculocutaneous nerve. [50, 49]  Humphreys and Mackinnon [96]  described transfer of redundant fascicles of both median and ulnar nerves to restore function to the biceps and brachialis branches of the musculocutaneous nerve. These transfers have been reported in patients with BRBPP. [97]  Transfer of three or more intercostal nerves can be performed to the musculocutaneous nerve for reconstruction of elbow flexion in cases of insufficient donor axons. [47]

Other nerve transfers described for use in BRBPP are the medial pectoral nerve–to–musculocutaneous nerve transfer, [98]  the radial nerve–to–axillary nerve transfer, [99]  ipsilateral C7 neurotization of the upper trunk, [100, 101]  and the contralateral C7 transfer in cases of pan-plexus root avulsions, [102]  though these transfers are less commonly used. Hypoglossal [103]  and phrenic nerve [104]  or phrenic nerve branch [105]  transfers have also been performed in patients with BRBPP, though their use is not recommended, owing to significant donor deficits.

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Postoperative Care

The patient’s affected upper extremity should be maintained in a Velpeau stockinette for 3 weeks postoperatively to maintain shoulder adduction. After this 3-week immobilization period, the child may be permitted to move freely.

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Complications

Complications of surgery for BRBPP include the following:

  • Infection
  • Hematoma
  • Seroma
  • Injury to nearby structures, including vascular structures and the thoracic cavity

Unique to this surgery is the possibility of further inhibiting function by injuring components of the brachial plexus that are normal or recovering. In this patient population, injury to the phrenic nerve can result in devastating pulmonary compromise that could require urgent diaphragmatic plication. In theory, an intercostal motor branch or a nerve to the rectus muscle can be transferred to the distal end of the phrenic nerve, just above the diaphragm, to provide some reinnervation of the diaphragm.

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Long-Term Monitoring

Initially, patients with BRBPP are monitored for wound management. At 4 weeks following surgery, patients are referred for therapy to regain active and passive ROM of the extremity. Recovery of some motor function may be noted as early as 3 months following surgery. Baseline motor function is usually achieved by 6 months. Patients continue to improve for up to 4 years, however, following surgery. Botulinum toxin has been used for management of muscle imbalance and has shown sustained benefits for elbow movement imbalance. [106] Secondary procedures such as muscle transfers, tendon transfers, osteotomies, or shoulder releases may also be necessary to maximize function.

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