Introduction
Brachial plexus birth injuries (BPBI) not resolving through natural recovery often result in various sequelae associated with the shoulder, elbow, wrist, and/or hand. These impairments often include decreased range of motion, strength, coordination, and sensation, although functional limitations associated with BPBI can vary substantially in extent and severity. Serial physical examination of children with BPBI is recommended to follow recovery patterns and to determine the need for appropriate therapeutic and/or surgical intervention. Over half of those with BPBI resolve spontaneously while the remaining children may require surgical or nonsurgical intervention to maximize functioning.
Shoulder
Regardless of the need for primary nerve repair, infants may demonstrate a substantial shoulder contracture as early as a few months of age. Most children with BPBI sustain an injury to the upper plexus (C5, C6) with or without C7. Children with functional impairments at the shoulder often exhibit weakness in abduction, external rotation, and terminal internal rotation due to decreased function of the deltoid and rotator cuff muscles. Unless nerve recovery is early and complete, the denervated muscles fail to grow normally, leading to relative shortening and contractures circumferentially about the glenohumeral joint. The most notable component of the global shoulder contracture is the lack of passive external rotation in adduction, as this motion is the only glenohumeral motion for which scapulothoracic motion cannot compensate. In addition, the persistent function of internal rotators, such as the pectoralis major, can create a functional imbalance of the muscles about the shoulder girdle, potentially exacerbating the contracture and leading to glenohumeral deformity. Up to 35% of infants and children with BPBI experience some degree of shoulder weakness, contracture, or joint deformity. Establishing shoulder alignment and stability is important due to the distal aspects of the upper extremity relying on the shoulder to function successfully.
Evaluation
Assessment of the shoulder may begin with active and passive range of motion at the very first session, captured through universal goniometry. Passive internal/external rotation is measured both in adduction and at 90 degrees of abduction. It is important to evaluate shoulder external rotation by passively manipulating bilateral upper extremities simultaneously to prevent natural trunk compensation if an internal rotation contracture is present. Muscle tightness of the pectoralis major is evaluated with direct palpation during passive external rotation in both adduction and abduction. Glenohumeral joint subluxation or dislocation may be determined by posterior palpation of the humeral head, asymmetry of axillary skin folds, and/or an apparently shortened humeral length. Dynamic instability of the joint and degree of scapular winging are assessed when the shoulder is adducted and internally rotated.
The Active Movement Scale and Modified Mallet Scale are both validated instruments utilized consistently with BPBI patients. The Active Movement Scale may be utilized at any age to capture active motion throughout the involved upper extremity, first with gravity eliminated, then against gravity. The original Mallet Scale has been modified to include six components of active motion focusing on shoulder motion: shoulder abduction, shoulder external rotation, hand to neck, hand to mouth, hand to back, and hand to stomach. As children age, it is important to take precaution to block trunk compensation and ensure slow motions are utilized to not allow momentum to impact demonstrated active motion. Imaging may provide additional information if an internal rotation contracture is noted. For those under 12 months of age, a shoulder ultrasound provides visual confirmation of shoulder alignment, while a shoulder MRI remains the standard of care for full assessment of glenohumeral dysplasia.
Therapy
Therapy is vital to children with BPBI regardless of whether surgery is indicated, although rehabilitative therapy can also preserve and build on gains made possible by surgical interventions. Therapeutic management addressing shoulder imbalance may include active and passive range of motion, use of taping to facilitate positional awareness and give feedback to relevant muscle groups, and use of neuromuscular electrical stimulation (NMES) for strengthening and biofeedback. When a muscle contraction is noted in a weak muscle, NMES can be utilized to facilitate muscle recruitment, provided the practitioner is skilled in its use. Knowledge of the physical and electrical components of this treatment modality is crucial.
Use of splints should be considered in cases where there is weakness, contracture, or to assist in preventing further deformity. Preemptive use of shoulder external rotation splinting may be worthwhile in helping to keep the shoulder developing well through early growth ( Fig. 13.1 ). Proper splinting and casting requires a strong collaboration between the physician and the therapist.
As children grow, the relationship between the shoulder and scapula becomes an area of focus as the scapula is noted to wing and/or tilt. Winging of the scapula is a common occurrence seen with children with contractures at the glenohumeral joint, as scapular winging compensates for limited glenohumeral motion. Joint mobilization and stretching may be utilized to address this limitation.
Botulinum Toxin
Children with incomplete recovery often demonstrate limitations due to cocontraction of agonist and antagonist muscles related to abnormal reinnervation patterns. Management of cocontraction can include temporary weakening of the more powerful muscle with botulinum toxin injection to allow a period of motor learning for the weaker muscle. In addition, the often powerful pectoralis muscle can be used to resist the necessary stretching of the subscapularis muscle, so temporary weakening of the pectoralis with botulinum toxin injection can facilitate appropriate passive range of motion. However, the use of botulinum toxin to directly treat contractures has fallen out of favor, as mounting evidence argues against muscle overactivity as the cause of the contractures.
Surgical Intervention
If active external rotation is absent but full passive range of motion is demonstrated, surgical intervention to restore active motion can consist of nerve reconstruction or tendon transfers. Nerve reconstruction can take the form of excision and grafting of the injured nerves of the brachial plexus or transfer of functioning nerves to paralyzed muscles (e.g., spinal accessory to suprascapular nerve transfer). The relative indications for these nerve reconstruction strategies are covered in a previous chapter. If active external rotation is absent and a persistent internal rotation contracture is noted upon exam, or if poor glenohumeral alignment is noted on imaging studies, surgical intervention may include a contracture release and tendon transfers. The first such procedure was described over a century ago. Since then, many techniques have been described, but most techniques include releasing a portion of the subscapularis muscle, with or without release of the joint capsule or other structures, and transferring the latissimus dorsi and/or teres major tendons to the posterior-superior rotator cuff, where they become active abductors and external rotators of the shoulder. These are the most common procedures utilized to address shoulder imbalance for those with BPBI. A surgical overview has been provided in Appendix A .
A general postoperative guideline for releasing the subscapularis includes having young patients be casted for 4 weeks to hold the shoulder in external rotation. Subsequently, the child returns to therapy without restriction once the cast is removed. If an orthosis is utilized instead of casting, patients are able to come out of the orthosis daily for bathing and active range of motion. Those not casted may begin therapy immediately after surgery without restriction. A general guideline following the subscapularis release and transfer of the latissimus/teres major includes the patient being casted or in an orthosis full time for 4 weeks. Therapy is then initiated with restrictions associated with protecting the transferred muscle(s) until 3 months after surgery. Restrictions typically include no passive range of motion into internal rotation or shoulder extension as well as no resistive activities. The shoulder and surrounding muscles need appropriate postoperative therapy to adapt to the new configuration, as well as to increase muscle function and strength. Often surgeons differ slightly in their surgical technique and postoperative protocol. If a patient is having surgery, the therapist should reach out to the surgeon to learn more about the procedure and the postoperative therapeutic plan.
A humeral osteotomy may be recommended for patients with long-term internal rotation contractures with substantial glenohumeral deformity or if the internal rotation contracture exists despite prior surgical attempts to improve alignment. An osteotomy is performed in the shaft of the humerus with internal fixation utilized to hold the new position. This new bony alignment creates a new set point for the available active rotation of the shoulder. Following the surgery, a sling is used for comfort only. Therapy may be initiated soon after surgery to facilitate active range of motion and functional use with the new positioning. Resistive activities and passive range of motion are prohibited until radiographic confirmation of bone healing has been completed.
Elbow
The natural resting position for many children with BPBI is an internal rotation position at the shoulder with a slight bend at the elbow. The reason for development of elbow flexion contractures has historically been unknown, although it has been thought to be due to residual muscle weakness. However, recent basic science data has shown that the elbow flexion contracture actually develops due to impaired growth and thus relative shortening of the biceps muscle, which may also be very weak. This shortening of the biceps may lead to loss of passive range of motion, which often worsens during periods of growth.
Evaluation
Assessment includes active and passive range of motion with use of goniometry. Radiographs may also be valuable in determining bony alignment and growth changes impacting an inability to fully extend the elbow, although bony deformity is a much less common limiting factor than it is at the shoulder. Anterior radial head dislocation is common, but does not in and of itself lead to increased functional difficulties, as it typically occurs in children with severe global brachial plexus involvement with limited functional recovery. Nonetheless, palpable radial head instability can be a concern to the family and can be noticed by the therapist.
Therapy
Because of the limited results of surgical correction of an elbow flexion contracture, splinting and casting are frequently used to maximize elbow extension. If an elbow flexion contracture of less than 20 degrees is noted, splinting may be utilized to maintain the position so it does not worsen. If an initial contracture of 20–40 degrees is noted, serial casting may be first utilized to improve elbow range of motion. This would then be followed by nighttime splinting to maintain gains made through the serial casting. Serial casting has been proven effective in addressing elbow flexion contractures in children with BPBI ( Fig. 13.2 ).
Surgical Intervention
The most common surgery performed at the elbow is a release of the flexion contracture through lengthening of the biceps and brachialis muscles, with or without joint capsule release. Although surgical results may show initial improvements greater than that obtained by serial casting, deterioration of passive elbow extension occurs over time. Overall, surgical treatments are only able to correct approximately half the passive extension deficit. Postoperatively, patients are casted for 4 weeks followed by splint fabrication. The splint is worn full time for an additional 2 weeks before restarting therapy 6 weeks after surgery. Use of the protective splint continues at this point although it may be removed for light functional use and active range of motion. Gentle passive range of motion may also be started at this time.
Forearm
Patients with C5, C6, and C7 involvement may demonstrate mild deficits in functional forearm supination due to delayed innervation of the supinator muscle and its biceps support. This often improves with time to a functional level of range of motion. Children with a global BPBI involving C8 and T1 have additional limitations throughout the forearm, wrist, and hand. Those with global injuries appear most prone to developing a supination contracture that limits functional use of the hand. Most daily needs are met through distal upper extremity functioning with the forearm in a pronated position. Forearm rotation can be best assessed using goniometry to capture active and passive range of motion.
Therapy/Surgery
Early therapeutic intervention may include the use of taping, splinting with a rotary strap, and/or serial casting to promote forearm rotation. If active rotation does not recover, or once a rotational contracture has developed, substantial improvement is only seen with surgical intervention. If the forearm remains supple through a full range of rotation, but the patient lacks active protonation, the distal biceps tendon can be rerouted from an active supinator to a pronator function. Following this procedure, patients are casted for 4 weeks and then are able to start therapy. A splint is fabricated for intermittent wearing for an additional 2–4 weeks. Restrictions include no passive or resistive activities until 3 months following surgery. For a fixed contracture, a derotational osteotomy of the radius and/or ulna is the most common surgical procedure performed to improve forearm positioning Postoperative care includes casting for 4 weeks and then therapy is initiated to facilitate active range of motion and functional use with new positioning. Resistive activities and passive range of motion are prohibited until radiographic confirmation of bone healing has been completed.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
