SURGICAL INDICATIONS

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Indications for timing of brachial plexus surgery for infants have been controversial. It has been shown that a longer time for recovery leads to a worse shoulder function and that those who regain elbow flexion after 6 months of age have worse function than those who regain it between 3 and 6 months (64). Those with recovery by 3 months have normal function. Those who had microsurgery at 6 months did better than those who spontaneously recovered elbow flexion at 5 months (65). Surgical intervention is commonly recommended for those having less-than-antigravity strength in elbow flexion at 6 months of age (66). Estimates vary that from 4% to 34% of those with BBPP will require surgery for clinical improvement (67).

Later brachial plexus injuries are divided into supraclavicular and infraclavicular injuries, supraclavicular being 75% and infraclavicular 25%. Supraclavicular injuries are generally felt to be due to traction of the plexus (classically in a motorcycle crash), and these have a worse prognosis than infraclavicular injuries (68). There may be a fracture of the clavicle or cervical transverse process, and supraclavicular fossa swelling may be seen. Dorsal scapular nerve or long thoracic nerve injury may be present. Supraclavicular lesions may also be due to falls; large objects falling on a shoulder, such as a tree limb; skiing or climbing; or contact sports, including football (52). Other etiologies are backpacks that are too heavy, tumors and gunshot wounds, or lacerations or animal bites. Those who have ipsilateral Horner's syndrome and persistent pain have a worse prognosis (52).

Infraclavicular brachial plexus injuries are more commonly associated with fractures and dislocations about the shoulder or humerus, occurring more often in older adults. The posterior cord, axillary nerve, or musculocutaneous nerve are classically involved. Infraclavicular injuries are less severe and have better outcomes (69). Infraclavicular plexus injuries may also be due to falls, motor vehicle collision, or tumors (52). Gunshot wounds, stab wounds, and failed attempts at shoulder reductions may cause infraclavicular injuries as well (70). Brachial plexus palsy has been reported after axillary crutch use, anesthesia positioning (particularly with table tilt), and after bony fracture with malunion (71). For severe injuries later in life, recommendations are for surgical exploration and nerve grafting, most commonly at 3 to 4 months post-injury (70,72).

SURGERY

Surgical interventions for brachial plexus palsy are varied. There may be electrical testing, including evoked potentials, and nerve conduction studies done to assess the nerves in the operating room to be as specific as possible with the procedures undertaken. Microsurgical repair yields results months later. Recovery is generally felt to proceed at the rate of approximately a millimeter a day or an inch a month. It is also believed that there is more nerve growth factor available in babies than older people so that both size and age have an impact in outcome. It is critical to have therapy postsurgery and to continue a faithful daily home program as well.

There are a variety of options for surgical procedures for brachial plexus injury Neurosurgery may include neurolysis in which scar and fibrotic tissue are removed from nerve tissue. Direct nerve transfers have the advantage of quick recovery time due to short regeneration distance versus neurotization, which requires interposition of a nerve graft. The sural nerve and great auricular nerve are commonly used as donor nerve fibers for these grafts (73). More recently, end-to-side neurorrhaphy is performed for those who have some intact fibers for augmentation. The advantage of this is not requiring a sacrifice of any other nerves. Not uncommonly, synkinesis of newly innervated muscles with contraction of muscles innervated by the donor nerve may be seen, and is treated with therapy (74). Synthetic nerve conduits are now available for nerve grafting.

Some classic nerve procedures involve transfer from a functionally less important nerve to a distal denervated nerve. Common examples include taking intercostal nerves to the upper trunk or to the suprascapular nerve. Another classic surgery is the Oberlin procedure, which transfers one or several ulnar nerve fascicles to the musculocutaneous nerve as it enters the biceps muscle (75). Transfer of the spinal accessory nerve to the suprascapular nerve is also commonly used for shoulder abduction. Contralateral C7 transfers have been performed both in adults and infants for those with multiple severe avulsions. This procedure has been shown to provide adequate elbow flexion as a result, and most patients have had only temporary sensory deficits on the ipsilateral C7 side (76). This procedure clearly illustrates the point that nerve grafts are not required to have their original source but can have function coming from a variety of intact neurologic structures. This allows for greater flexibility and creativity in the surgeon performing the procedure, aiming for recovery of function.

Glenoid dysplasia with posterior shoulder subluxation is frequently a complication of children after BBPP. It was commonly thought to be the result of a slowly progressive glenohumeral deformation due to muscle imbalance and possible physeal trauma, but it was found that posterior shoulder dislocation happened at a mean age of 6 months, with rapid loss of passive external rotation. There was no correlation between the initial neurologic deficit and the presence or absence of dislocation (77).

Many musculotendinous surgical procedures are performed for children with BBPP. It has been shown that latissimus dorsi and teres major tendon transfer to the rotator cuff, along with musculotendinous lengthening, will provide improved shoulder function but no significant change in the bony position of the shoulder or humerus. This procedure does not decrease glenohumeral dysplasia (78).

With internal rotational contracture and glenohumeral joint deformity, along with significant abnormality of glenohumeral joint, a derotational osteotomy can result in improved shoulder function, along with improved internal rotation contracture (79).

Some children with BBPP have been described to have arthroscopic release of shoulder deformity alone before 3 years, and for those over 3 years of age, arthroscopic release with latissimus dorsi transfer. They all show improved shoulder position, but they do have loss of internal rotation. Some of the children under 3 years of age do have a recurrence and require a second procedure with a latissimus dorsi transfer (80).

In adults, performing a glenohumeral arthrodesis, in patients with upper plexus palsy with functional distal arm, as well as in those with total plexus palsy, has been shown to increase functional capabilities. The strength of the pectoralis major is a significant prognostic factor for outcome (81).

Performing wrist arthrodesis in adults with brachial plexus injury is done for improved function as well as pain relief. There will be limitations after having this procedure, and potential patients need to have full information in order to know what to expect prior to the procedure. There also remains some controversy regarding the ideal position to place the hand, which is generally placed in slight wrist extension and ulnar deviation in order to have the most powerful grip (71,82). A dramatic surgical procedure sometimes performed for children and adults with brachial plexus palsy is a free muscle transfer, most commonly performed with the gracilis muscle. The muscle is transferred with its vascular and nerve supply and attached to these in the arm. This procedure has been described as having reliable results for elbow flexion and wrist extension (71).

PAIN

Pain has not been reported as a severe problem in birth brachial plexus injury, although with one study reporting biting of the limbs in less than 5% of the cases, it is possible that this is a manifestation of pain. Self-mutilation has been reported in youngsters after a birth brachial plexus injury. A study of 280 patients with a birth brachial plexus injury found that 11 of these children had self-mutilating behavior by biting or mouthing the affected arm. The age of onset was between 11 and 21 months, and the duration of the behavior was 4 to 7 months. This was more frequent in children who underwent surgery, with 6.8% of these children, and 1.4% of children who did not have surgery. It is unclear if this is due to surgery or the severity of the injury or a combination of these (83). It is also possible that this is a response to the unusual sensation of the recovering nerve, possibly a manifestation of what we see on examination as a Tinel's sign. It has been felt, however, that it is more likely biting with the resumption of nerve growth with sensation of tingling as there is recovery occurring, but this is not proven.

In those who have later traumatic or nontraumatic brachial plexus injuries, pain can be a significant problem. It has been described most commonly with avulsions as severe burning and crushing pain most commonly in the hand. This may develop days to months after the injury and almost always within 3 months. It is most commonly resolved within several years, but approximately 20% of those with pain have severe, long-lasting disruptive pain (84). This can be treated with transcutaneous nerve stimulation classically from C3-T2. Medications, including antidepressants and anticonvulsant agents, have been affective. Topical treatments, including topical lidocaine 5% pain patches, are sometimes useful. Nerve surgery is commonly effective in resolving pain (85,86). The author has seen children with traumatic brachial plexus injuries and severe pain complaints prior to their nerve procedure wake up postoperatively in the recovery room excited that the pain is gone. Amputation is not effective for resolving the pain (87).

 
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