The risk factors associated with birth brachial plexus palsy (perhaps incorrectly termed obstetrical palsy) are well known and include macrosomia (particularly weights greater than 4000 g), cepha-lopelvic disproportion leading to shoulder dysto-cia, and maternal obesity and diabetes. Two general presentations have been recognized. The most common injury occurs to the upper elements of the plexus, either C5 + C6 roots with the site of injury at their fusion into the upper trunk. This has been termed Erb's palsy. Injury to C7 may complicate the situation, but, if present, the term Erb's palsy is still used. The injured arm is held abducted and internally rotated at the shoulder, extended at the elbow and with forearm pronated and the wrist frequently held flexed. The other presentation is one characterized by the involvement of all elements of the plexus. This has been termed a global palsy. The involved limb is flail, the hand demonstrates trophism, and there is typically a Claude Bernard-Horner's sign (lagop-thalmo and meiosis.)
The overwhelming majority of babies who suffer only an upper plexus injury associated with the birth process rapidly recover high function, though it is occasionally a less than fully normal state. Their nerve injury is rarely to the level of Sunderland IV (severe axonotmesis) or 5 (neu-rotmesis) . The babies that show signs of rapid recovery (ie, within days or weeks) rarely have functional deficits that will be reliably benefited by surgery, either microneurosurgical or conventional. The opposite is true for babies with global palsies who do not recover very rapidly. These babies all have some combination of root rupture and avulsion and will not experience predictable spontaneous recovery. In spite of a large experience in managing babies with birth palsies, there is still controversy regarding the roles of micro-neurosurgical and conventional treatment.
The role of microneurosurgical treatment of birth palsies remains controversial in terms of indications and timing. The greatest controversy exists regarding the typical baby with an injury to only the upper plexus (C5, C6.) This baby has an essentially normal hand and, frequently, normal wrist function, and lacks only some shoulder abduction and external rotation and elbow flexion. It is the rare baby that does not eventually spontaneously recover useful elbow flexion and some shoulder abduction. Thus, the persistent deficit in the great majority of nonmicrosurgically operated babies, and even in those who undergo microneurosurgical reconstruction before ages 9 to 12 months, is reduced shoulder elevation and external rotation. Various investigators [9,39,40] have demonstrated that in both groups, operated and nonoperated, conventional treatment, including internal rotation contracture release, muscle rebalancing, splinting, and prolonged therapy, can upgrade shoulder function, though seldom to the level of the uninjured side. The surgical literature is equivocal regarding whether the ultimate functional outcome for babies with an isolated C5, C6 lesion who demonstrate evidence of muscle recovery in a "timely" fashion is significantly superior in microneurosurgically reconstructed babies versus those allowed to evolve spontaneously and undergo secondary conventional procedures. The controversy focuses primarily on what constitutes "timely" evidence of muscle recovery. Some surgeons advocate plexus exploration for C5, C6 babies who fail to show evidence of biceps recovery by 3 months of age [9,41]. Others wait 6 months before making a decision regarding surgery and advocate the recovery of additional muscles, such as wrist extensors, before making that decision . Still others advocate a longer period of observation . There is currently a multicenter study comparing early (3 months of age), later (6 months of age), and no surgery. One primary goal of the study is to answer several of these key questions.
Babies with complete (global) palsies
There is much less controversy regarding babies who suffer injury to all elements of the plexus. Complete or global palsy at birth that does not evolve within days to a pattern more suggestive of an upper plexus injury is an indication for early microneurosurgical treatment. As opposed to the circumstances in the adult with a total brachial plexus palsy, or the more rare, isolated C8, T1 palsy (Klumpke), there is the possibility of restoring good hand function and even intrinsic muscle function if early plexus reconstruction is performed in babies with global palsy. This is the one good opportunity to make these babies better, because the results of secondary conventional surgery, such as muscle-tendon transfers, are far from predictable. One must consider that any muscle that might be considered expendable later (for a secondary tendon transfer) was once a paralyzed muscle itself. The secondary procedures most reliable to improve hand function include radio-carpal fusion to control the wrist in the child who has recovered some finger movement.
Was this article helpful?