Pediatric Brachial Plexus Palsy

Pediatric Brachial Plexus Palsy


Nathan J. Ranalli and Tae Sung Park


Pediatric obstetric brachial plexus palsy, or neonatal brachial plexus palsy (NBPP), refers to the condition arising from a traumatic insult to one or more of the cervical roots C5–C8 and T1 preceding, during, or following the birth process. Although improvements in obstetric care and heightened attention to documented risk factors for injury have resulted in reduced rates of occurrence, the incidence of NBPP has been reported to be between 0.38 and 5.8 per 1,000 live births; an extensive epidemiologic review by Foad et al in 2008 demonstrated an incidence of 1.51 cases per 1,000 live births in the United States.13 For many children, the deficits are mild and transient, with rates of spontaneous recovery between 75 and 95% cited in the literature.47 More recent reports, however, have suggested that these outcomes may be overly optimistic, finding much lower recovery rates and significant permanent disabilities in affected patients who were managed conservatively.4,​814


In the past several decades, it has become increasingly apparent that the role of the pediatric neurosurgeon in the management of NBPP centers on the proper selection of patients for whom surgical intervention will be of benefit. This chapter reviews the anatomy and pathophysiology of NBPP, discusses the clinical presentation and comprehensive evaluation of these patients, and illustrates the current approach to the operative treatment of NBPP; the focus is on surgical timing, microsurgical techniques, treatment adjuncts, prognosis, and secondary reconstruction.


59.1 History


Although the first clinical description of birth-related brachial plexus injury was made by William Smellie in 1764, the term obstetric palsy was not coined until 1872. Guillaume Duchenne detailed four cases of upper brachial plexus palsy due to excessive traction on the arm and shoulder during birth, with resultant root avulsions.15,​16 Two years later, Wilhelm Erb identified the site at which the C5 and C6 nerve roots join in the neck as the location of injury in patients with weakness of the deltoid, biceps, coracobrachialis, and brachioradialis muscles; therefore, the term Erb (or Erb-Duchenne) palsy refers to the classic upper brachial plexus injury involving only the upper trunk of C5 and C6 with or without C7.17 A century later, Augusta Klumpke illustrated the relationship between the Horner sign and T1 root avulsion in brachial plexus lesions; the term Klumpke palsy, the least common pattern of injury in NBPP, refers to an insult isolated to the lower trunk of the C8 and T1 roots.18


The first report of surgical treatment for NBPP came from Robert Kennedy in his 1903 publication describing the neuroma resection and neurorrhaphy of the injured fifth and sixth cervical roots in a young boy with Erb palsy, and the positive results were documented pictorially.19 A subsequent review of 1,100 cases of obstetric brachial plexus palsies by Sever in 1925 concluded, however, that patients managed conservatively or surgically had the same outcomes.20 In light of this finding, primary operative intervention for NBPP was rarely employed until the advent of microsurgical techniques and improved pediatric anesthesia in the 1970s. The published works of Millesi, Narakas, and Gilbert et al, each highlighting favorable results in patients with NBPP treated with direct surgical repair, rekindled an interest in the operative treatment of birth brachial plexus palsy that continues to this day.2123


59.2 Epidemiology


At present, NBPP occurs in more than 5,400 children born in the United States each year, and rates are nearly equal between male and female newborns.24,​25 Although some authors have cited congenital malformations and uterine cavity abnormalities as possible causes of obstetric brachial plexus palsy, the presumed etiology of NBPP is difficult childbirth and the excessive application of lateral traction forces to the nerves during delivery.2628 This scenario usually occurs in the setting of shoulder dystocia, in which the upper extremity is pulled in excess of nerve tolerance during extrication, or of hyperextension of the arms in a breech delivery.29 Trauma to the upper roots of the plexus typically takes place in a vertex delivery with shoulder dystocia when the neck is laterally flexed with the arm in adduction to free the shoulder from the pubic arch. Because of the more common left occiput anterior presentation of the descending fetus, right-sided lesions occur more frequently; injury to the posterior shoulder, however, may occur when that shoulder is lodged on the maternal sacral promontory during the birthing process.26,​30 Bilateral injuries have been reported with breech presentation, although unilateral insults to the upper roots are still seen more often in that setting.31,​32 Several investigations have demonstrated that more than 1% of cases of NBPP occur following cesarean deliveries.33,​34


59.3 Risk Factors


Despite increased awareness of the problem, NBPP is not a preventable disease. In fact, a study by Mollberg et al showed that the incidence of obstetric palsy has actually increased in one industrialized country over a recent 10-year period.35 As a result, significant attention has been paid to the identification of predisposing factors that may be associated with the occurrence of NBPP. These include maternal characteristics, such as obesity and excessive maternal weight gain, primiparity, grand multiparity, gestational diabetes, and advanced maternal age (older than 35 years); labor-related factors are shoulder dystocia, prolonged second stage of labor, vaginal breech delivery, instrument (vacuum)–assisted vaginal delivery, and epidural analgesia. The most important fetal trait is macrosomia (birth weight > 4,500 g).3640 Several recent studies have determined that shoulder dystocia and the ancillary maneuvers required to deliver the shoulders are the most prevalent risk factor for NBPP, although prior reports suggested it is much less common.4143 The observation that some patients with NBPP have one or more risk factors while others have none has led some investigators to hypothesize that not all permanent brachial plexus injury is due to birth-related traction, and some patients may have an undefined or inherent susceptibility to the condition.4446 Other traumatic lesions, such as fractures of the clavicle and humerus, facial nerve injury, cephalohematoma, and torticollis, have been associated with obstetric brachial plexus palsy.41,​4750


59.4 Surgical Anatomy and Pathophysiology


Peripheral nerve injuries have been classically described and categorized, first by Seddon in 1943 and later by Sunderland in 1951.51,​52 In Seddon’s classification (and Sunderland I), neurapraxia refers to a physiologic block of nerve conduction within affected axons without a loss of axonal continuity; it is the mildest form of injury, and full recovery is generally observed in days to weeks. Axonotmesis (Sunderland II–IV) involves a relative loss of continuity of the axon and its myelin sheath, but with preservation of the epineurium and perineurium; wallerian degeneration and scar formation occur, but recovery may take place without surgical intervention if the axons successfully grow back to reach the target muscle. Neurotmesis (Sunderland V) describes a total severance or disruption of the entire nerve fiber; recovery from this injury is not possible without timely surgical treatment. Mechanically, these insults have been referred to as stretch (Sunderland I), varying degrees of rupture (Sunderland II–V), and avulsions.53


More clinically relevant than pathologic severity is the anatomical localization of the brachial plexus injury. Most authors recognize four major patterns of injury, described by Narakas and others, involving three plexus palsy categories: upper, lower, and total.5456 The first and most common is a purely upper brachial plexus lesion affecting C5 and C6 (Erb palsy) and causing weakness of only the deltoid and biceps; several reports have demonstrated evidence of rates of spontaneous recovery as high as 90% in these cases.57,​58 The second presentation is that of an injury involving the C5, C6, and C7 roots. The arm is internally rotated and adducted at the shoulder, the elbow is extended, the forearm is pronated, and the wrist is flexed with fingers extended, resulting in the “waiter’s tip” posture. The next most common type of birth palsy, accounting for 9 to 26% of cases of NBPP, is that of a total brachial plexus injury involving the C5–T1 roots; it is the most devastating injury to the brachial plexus with the least favorable outcomes.4,​26,​59,​60 These newborns manifest flaccid, insensate paralysis of the entire arm and hand with pale or mottled skin due to vasomotor impairment; Horner syndrome (ptosis, myosis, enophthalmos, and anhydrosis) may or may not be seen. The final and exceedingly rare pattern of injury is that of Klumpke palsy, due to damage of the lower roots C8 and T1. The clinical features include a “claw hand” posture and Horner syndrome and are seen in fewer than 1% of obstetric palsies.57


Neonatal injuries of the brachial plexus may be further subcategorized as supraclavicular, affecting the roots and/or trunks, or infraclavicular, involving plexus lesions distal to the level of the cords. The determination of the pre- or postganglionic nature of the level of injury is important for prognostic purposes.61,​62 Preganglionic lesions are avulsions from the spinal cord that cause denervation weakness in all muscles supplied by the injured root (motor cell bodies in the spinal cord), but nerve conduction (sensory cell bodies in the dorsal root ganglion) is intact. Damage to the nerves arising in proximity to the ganglion, including the phrenic (elevated hemidiaphragm), long thoracic (winged scapula), dorsal scapular (absence of rhomboid), suprascapular (rotator cuff), and thoracodorsal (latissimus dorsi) nerves, or the presence of Horner syndrome (preganglionic sympathetic fibers to the eye join the sympathetic chain from the T1 spinal nerve) resulting in mydriasis and ptosis suggests a significant preganglionic injury.63 These cases do not recover motor function spontaneously. Postganglionic ruptures generally result in sensory conduction delay and the paralysis of target muscles innervated by the trunk level and beyond; such lesions have sufficient proximal and distal nerve components relative to the site of injury to be amenable to surgical repair and reconstruction.64 A common pattern of injury is postganglionic rupture of the roots and trunks in the supraclavicular compartment (Erb palsy) and preganglionic avulsion in the infraclavicular compartment.59,​65


59.5 Natural History and Recovery Potential


As noted in the introduction, previous reports have documented that the majority of patients with NBPP have an overall favorable prognosis, showing that 70 to 95% had a complete spontaneous recovery with conservative management (physical therapy).6,​55,​6668 Gordon et al found that 90% of patients showed improvement by 4 months of age, and Greenwald and others reported recovery within the first 3 months in 92% of patients.4,​69 More recently, however, Hoeksma et al published a complete neurologic recovery rate of only 66% in a series of 56 patients, and Bager found severe impairment in 22% of 52 Swedish children with NBPP.8,​70 We found at our own institution that 66% of 80 infants with NBPP achieved complete recovery, defined as antigravity movement in the biceps, triceps, and deltoid muscles by 4.5 months of age.9 In the cases of complete recovery, all patients achieved three-fifths strength in all three muscle groups by 5.5 months at the latest, and any permanent weakness was apparent by 6 months of age as two-fifths or lower strength in the biceps, triceps, or deltoid muscle. Narakas determined that satisfactory recovery in patients with total palsy was extremely unusual, and Al-Qattan et al found that none of 22 patients with Horner syndrome in their series achieved a positive outcome.54,​71 Factors that portend a worse prognosis include total plexopathy and lower plexus injury, Horner syndrome, and multiple root avulsions.6,​26,​59,​72 A systematic review by Pondaag et al in 2004 concluded that the most commonly reported high recovery rates were based on inadequate study methodologies limited by insufficient follow-up periods, unclear criteria for permanent injury, and lack of a final evaluation by a brachial plexus specialist.10 An evidence-based review focusing on prognosis following NBPP by Foad et al, published in 2009, reported that of 11 studies from 1966 through 2006 that met criteria for inclusion, only four achieved an Oxford evidence-based grading scale level of 1 or 2; they concluded that the quality of the literature on this subject is poor and that the rates of spontaneous recovery are significantly lower than those documented in early reports (even among patients with upper trunk palsies, only 64% had a spontaneous recovery of biceps function at 3 months).73


Despite the discordant data, several points remain clear. Most cases of NBPP are transient and show some improvement beginning as early as 2 weeks of age with supervised home therapy to support passive range of motion.74 Infants who achieve partial antigravity strength in upper trunk–innervated muscles within the first 2 months are likely to progress to complete recovery over the next 2 years, whereas those who do not recover antigravity strength by 5 to 6 months after birth are unlikely to recover completely without surgical intervention.75 Global shoulder function is increasingly impaired with longer duration of biceps muscle recovery, and these patients are likely to experience permanent, debilitating limitations of motion and strength as well as joint contractures.76 Infants who demonstrate no signs of recovery and have a persistently flaccid arm at 2 months of age have a total palsy with an unfavorable long-term prognosis.26,​41,​67,​77


59.6 Patient Evaluation


59.6.1 Neurologic Examination


At our institution, patients in whom NBPP is diagnosed are evaluated as soon as possible after birth in a comprehensive multidisciplinary brachial plexus clinic comprised of a pediatric neurosurgeon, a pediatric neurologist, an orthopedic surgeon, physical and occupational therapists, a neuroradiologist, an electrophysiologist, and a nurse coordinator. A complete examination is performed, with the focus on a detailed obstetric and birth history, with the presence or absence of the aforementioned risk factors for NBPP noted. A careful assessment of passive range of motion of the involved arm, forearm, hand, and shoulder is made, often by simply observing spontaneous activity and coaxing the patient to reach for items with and without assistance. Numerous scales exist for evaluating motor strength, including the British Medical Research Council muscle movement scale, the Gilbert and Tassin muscle grading system, the Mallet scale, and the Hospital for Sick Children (Toronto) muscle grading system.7881 We use the modified and simplified Medical Research Council scale (MRC 0–5) for all infants and, for patients older than 2 years who are able to cooperate, the Mallet scale in order to document functional changes in the shoulder and arm. In newborns, the presence or absence of a pinch response may provide useful information regarding sensory loss; evidence of self-mutilation of the fingers may be appreciated as well. Narakas classified the sensory responses of infants with NBPP into four groups.54 Suspected associated injuries like rib, spine, clavicle, or humerus fractures or observed asymmetry of chest wall expansion should be clarified with inspiratory and expiratory plain radiographs. Fractures of the humerus and clavicle, the bones most commonly broken during delivery, can cause compression of the brachial plexus and a pseudoparalysis that mimics true NBPP.78,​82,​83 Other entities in the differential diagnosis include congenital aplasia of brachial plexus nerve roots, congenital Varicella of the upper extremity, umbilical cord palsy, and intrauterine maladaption palsy.


Typically, the inflammatory component of the birth trauma resolves over several days or weeks, and the true nature of the child’s injury becomes more apparent. Many patients with palsies recover completely in this time frame, signifying a neurapraxic insult, whereas others improve from an entirely flaccid arm to a purely upper plexus palsy. Physical therapy in the form of passive range of motion exercises is initiated at home within the first month, and the patient returns to the clinic 4 weeks after birth. If the child still has a total palsy, particularly in the presence of Horner syndrome, the poor prognosis is explained to the parents and surgical intervention is discussed; numerous publications support microsurgical reconstruction in these infants by 3 months of age.59,​64,​79,​84 If the patient exhibits evidence of improving hand function without shoulder or biceps recovery, physical therapy is continued, and he or she is seen on a monthly basis.85 By 3 to 4 months of age, infants with antigravity strength or greater in the biceps, triceps, or deltoid muscle may be followed expectantly; children with less than antigravity strength in each of these muscles undergo neuroimaging and electrophysiologic studies in preparation for likely surgical intervention.9 If at 6 months of age the aforementioned muscles still have not recovered antigravity strength, brachial plexus exploration and repair are recommended. This practice pattern is based on our own prospective study of conservatively managed patients, in which we found that antigravity muscle strength at 3 months is prognostic for progression to a full recovery without an operation; similar strength testing at 6 months identifies those patients with less than antigravity strength who will not achieve a satisfactory outcome (antigravity strength) without surgery.86 We believe this approach minimizes unnecessary surgical intervention in children destined to recover spontaneously yet avoids the development of irreversible joint contractures or permanent muscle atrophy in those patients who will ultimately benefit from microsurgical repair.


59.6.2 Other Tests


Ancillary studies often used in the evaluation of a patient with NBPP include plain radiography, electromyography (EMG) and nerve conduction studies, magnetic resonance (MR) imaging, and computed tomographic (CT) myelography. As mentioned, when phrenic nerve injury is a concern on examination, chest X-rays should be obtained to look for an elevated hemidiaphragm; when fractures of the ribs, clavicle, spine, or humerus are present, radiographs of the specific site of suspected injury should be obtained.


If a patient presents with NBPP without evidence of obstetric trauma and an intrauterine injury is considered, EMG is performed within a week of delivery to assess for denervation and to clarify the timing of the event.87,​88 When surgical intervention is proposed, EMG and nerve conduction studies are undertaken in some centers 3 months after birth. Details regarding the extent and distribution of the brachial plexus injury, as well as the expected pattern of recovery, may be collected; additionally, evidence of normal sensory conduction in the setting of severe motor weakness suggests a nerve root avulsion or preganglionic injury. Although EMG is standard in the work-up of adult brachial plexus injuries, its utility in the evaluation of NBPP is not as clear. Several studies have suggested that because denervation disappears early in newborn trauma and extensive collateral sprouting occurs rapidly to affected muscles, EMG may not accurately portray the severity of the clinical condition.89 We have not found EMG to be particularly helpful in our own practice.


When the decision is made to proceed with brachial plexus exploration, we use T1- and T2-weighted fast spin-echo cervical MR imaging sequences to look for pseudomeningoceles as a marker for nerve root avulsion, as well as any sign of spinal cord injury.90,​91 It is worth noting, however, that 15% of pseudomeningoceles are not associated with complete nerve root avulsion, and 20% of surgically diagnosed avulsed roots may not be associated with a pseudomeningocele.49,​92 A retrospective review by Smith et al in 2008 demonstrated in a small group of infants with birth-related brachial plexus injuries the ability of MR neurography to aid in the anatomical localization and characterization of nerve swelling, neuromas, and denervation changes.93 CT myelography is an invasive alternative to MR imaging that provides a better delineation of the nerve roots and intervertebral foramina but requires general anesthesia, lumbar puncture, intrathecal contrast, and exposure to radiation.


59.7 Timing of Surgery


The primary clinical dilemma is to determine if an infant with NBPP warrants surgical exploration and reconstruction, and the absence of motor recovery is the main indication for operative intervention. Because these patients have varying degrees of nerve pathology (Sunderland II through IV) and their neuromuscular recovery following conservative management versus that after microsurgical intervention have not yet been compared in a prospective or randomized controlled manner, the timing of surgical treatment remains controversial.94 As early as 1917, Wyeth and Sharpe advocated surgery if there were no signs of motor recovery 3 months after birth.77 Many authors cite Gilbert and Tassin’s classic study of 44 children with NBPP in whom recovery of the biceps muscle at 3 months of age served as the indicator for expected spontaneous recovery (shoulder function was better in infants who showed biceps and deltoid recovery before 3 months) and recommend surgical exploration at 3 months if sufficient improvement has not occurred.80 Laurent et al espoused close monitoring of the triceps and deltoid muscles, in addition to the biceps, to determine microsurgical intervention.59 Chuang et al proposed that an aggressive approach (exploration at 3 months) is indicated for total palsy but only relatively so for lesions of the upper plexus.95 We found in our own series that patients who continued with less than antigravity biceps strength by 6 months of age had unsatisfactory outcomes with nonsurgical management.9 Terzis and Papakonstantinou argued for operative intervention at 4 to 6 weeks in patients with severe global injuries and at 3 months in children with isolated C5–C6 deficits and absence of antigravity biceps or deltoid recovery.25 Clarke and Curtis, on the other hand, recommended employing the “cookie test” to evaluate isolated elbow flexion recovery at 9 months of age as a measure of prognosis and to guide surgical treatment.78


59.8 Surgical Treatment


59.8.1 Anesthesia and Exposure


Before the operation, we make a concerted effort to counsel the parents regarding expectations and emphasize that the goal of surgery is to improve the functional capabilities of the arm, that it may never be completely normal, and that recognizable benefits may not appear for up to 6 months.


Surgery is performed under general anesthesia with a short-acting neuromuscular agent to permit intraoperative electrical stimulation.30 Following induction, the patient is positioned supine with a gel shoulder roll placed to elevate the clavicular region, and the head is rotated contralaterally. The entire neck, chest, and affected upper extremity and both lower limbs are prepared in a sterile manner to allow visual inspection of the muscles of the affected arm during surgery and to accommodate the potential need for bilateral sural nerve graft harvesting; this last point has been modified recently at our own institution as we have started using a peripheral nerve allograft in lieu of sural nerve autografts (Avance; AxoGen, Alachua, FL) in order to spare the patient a second (or third) surgical site. For an Erb or upper trunk palsy, a standard supraclavicular approach is used, whereas treatment of the lower plexus requires an infraclavicular exposure. The incision for the former begins two fingerbreadths beneath the mastoid tip and follows the posterior border of the sternocleidomastoid muscle to the midpoint of the clavicle; if a combined approach is indicated, the incision is extended laterally along the superior border of the clavicle to the deltopectoral groove and curved inferiorly to the anterior axillary fold. The entire operation is done under microscopic visualization.


Once the incision is made through the skin and platysma muscle for the supraclavicular approach, the flaps are raised, and a layer of fibrofatty tissue overlying the brachial plexus posterior to the sternocleidomastoid muscle is elevated with sharp dissection. The omohyoid muscle is divided, and the transverse cervical vessels are retracted or cauterized. Dissection continues down to the clavicle, with subsequent division of the subclavius muscle and clavicular periosteum. Although some authors routinely perform a clavicular osteotomy to improve exposure for combined approaches, others connect the supra- and infraclavicular plexus elements through subclavicular blunt dissection; if necessary, the clavicular portion of the pectoralis major muscle may be dissected from the clavicle, with preservation of the pectoral nerve, in order to expose the cords of the brachial plexus.96


The first goal is to reveal the C5 and C6 nerve roots and upper trunk, which requires identification of both the phrenic nerve along the anterior scalene muscle and the spinal accessory nerve arising from the C4 root; the latter may be seen at the posterior junction of the upper and middle thirds of the sternocleidomastoid muscle. Direct electrical stimulation and observation of responses are used throughout the dissection and aid in the labeling of these nerves. The upper trunk neuroma is likely to be readily apparent, and the C5 root is identified by tracing the most superficial portion of the upper trunk toward the neural foramen. The anterior scalene muscle is then divided and partially resected to provide access to the C6–T1 nerve roots; care must be taken when the T1 root is exposed, given its proximity to the pleura and subclavian vessels. Soft Silastic (Dow Corning, Midland, MI) vessel loops are used to designate and retract the roots, while the three trunks are identified close to the clavicle and freed from surrounding fibrotic tissue. The dorsal scapular and suprascapular nerves will be located arising from the C5 root and upper trunk, respectively; the long thoracic nerve will often be found under the upper trunk above the middle scalene muscle. Infraclavicular exposure is achieved by dissecting along the deltopectoral groove, with subsequent division of the pectoralis major at its insertion into the humerus and at the midpoint of the pectoralis minor; the cephalic vein is preserved, and marking sutures are used in the pectoralis major to facilitate closure. At this point, the cords of the brachial plexus as well as the median, ulnar, musculocutaneous, and axillary nerves may be identified.


Traditionally, we have harvested autologous sural nerve grafts through bilateral open posterior lower leg stepladder incisions; endoscopic harvest of the sural nerves has also been described.97 Because the sensory sural nerves are smaller than the mixed nerves of the brachial plexus, multiple segments of sural nerve are needed following neuroma resection to create an adequate graft spanning the distance from nerve root to trunk. This requires a second or third incision, increases the risk for wound infection, and may cause postoperative pain or paresthesias. Recently, we have instead used a decellularized and sterile extracellular matrix processed from donor human peripheral nerve tissue called Avance. Alternative donor sites include nerves in areas of the patient’s own plexus where reinnervation is unlikely to occur, including the medial cutaneous nerve of the forearm.


59.8.2 Resection of Neuromas


Surgical options for the treatment of neonatal brachial plexus palsy include neurolysis, complete or partial resection of the neuroma, and repair by nerve grafting with or without intra- and/or extra-plexus nerve transfers.98 External neurolysis alone is employed only when the neural elements show evidence of mild traction injury without disruption of the perineurial sheath; the resection of conducting neuromas in continuity has been shown to have better results than neurolysis alone.99 Nevertheless, controversy exists regarding the optimal intraoperative management of neuromas, particularly in light of the fact that the use of nerve action potential measurements during surgery as a prognostic tool has not been validated in the pediatric population.100,​101 Some authors resect all neuromas unless distinct fascicular architecture is observed.26,​29,​41,​67 Laurent and colleagues depend on the intraoperative assessment of compound muscle action potentials (CMAPs) across a neuroma to determine whether to perform neurolysis or neuroma resection and nerve grafting; a drop in the CMAP of more than 50% indicates resection, and a drop of less than 50% results in neurolysis.58,​59,​102 We combine a semiquantitative evaluation of muscle contraction in response to electrical stimulation of the nerve root proximal to the neuroma with intraoperative inspection of the neuroma, awareness of the preoperative muscle strength, and knowledge of the MR imaging findings to arrive at a decision. Generally, if the root or trunk is ruptured and electrical stimulation of up to 10 milliamperes generates no or minimal muscle contraction, the neuroma is resected. If there is evidence of nerve root avulsion and weak conduction through the remaining nerve root, then the nerve root sheath is divided. If the brachial plexus is in continuity but elicited muscle contraction is poor, the neuroma is resected. If the brachial plexus is in continuity and strong muscle contraction is observed following electrical stimulation of the proximal nerve root and the neuromas are not extensive, no resection is undertaken.


59.8.3 Repair Procedures


The primary objective of surgery for Erb or upper trunk palsy is to restore shoulder and biceps muscle function through a variety of grafting and neurotization procedures. These include using the stumps of the C5 and/or C6 roots, the C7 nerve root, or the spinal accessory nerve for grafting to all or part of the upper trunk, suprascapular nerve, and axillary nerve arising from the posterior cord. For total plexus injury, multiple nerve grafts must be employed. If several nerve root stumps are identified, these are divided and used for grafting all trunks and cords of the brachial plexus. If only a single nerve root stump is accessible, it is grafted to the musculocutaneous nerve. All nerve grafts should be prepared 10 to 15% longer than the measured defect length and combined to match the diameter of the host nerves. Neurorrhaphy is performed with 9–0 Prolene (Ethicon, Somerville, NJ) epineurial sutures combined with fibrin glue.


Nerve root avulsions require neurotization. Historically, this has meant nerve crossover or transfer between an uninjured neighboring donor nerve and a distal segment of a nonfunctioning nerve directly or with grafts. Nerve transfers involve motor-to-motor neural connections and may be used primarily or in late cases to augment function in the setting of partial neurologic recovery.63 Spinal accessory, phrenic, intercostal, medial pectoral, thoracodorsal, long thoracic, and subscapular nerves have all been used for neurotization. When a transfer of the spinal accessory nerve to the suprascapular nerve is used to reinnervate the infra- and supraspinatus muscles, care must be taken to section the nerve distal to the first branch to the trapezius muscle in order to avoid a significant motor deficit.22,​103 This can be combined with a transfer of the long head of the triceps motor branch of the radial nerve to the anterior portion of the axillary nerve for improved shoulder abduction.10,​104106 Al-Qattan and others have employed the technique described by Oberlin et al for transferring the fascicles of the ulnar nerve that supply the flexor carpi ulnaris to the motor branches of the biceps in patients with good recovery of shoulder function but little or no elbow flexion; more recently, transfer of the motor fibers of the median nerve and medial pectoral nerve has also been described in such children with good success.107111 We perform the transfer only in the setting of a secondary operation, either when the primary neurolysis/grafting did not result in adequate biceps function (as above) or when the primary exploration revealed such severely traumatized roots/trunks that grafting was impossible (one patient who returned at a later date for multiple transfers). We do think, however, that the Oberlin transfer could be considered at the primary operation for a patient who achieved spontaneous recovery of shoulder function without satisfactory recovery of biceps function by the 6-month time point. The phrenic nerve transfer has also proved safe and effective in adults with normal diaphragmatic function but is not recommended in infants in light of their immature respiratory system and greater risk for fatal pulmonary complications. Additionally, the long-term efficacy of neurotization with the long thoracic, thoracodorsal, subscapular, and pectoral nerves in babies is unknown.


Wound closure is performed in layers, including reinsertion of the pectoralis major muscle (if sectioned) and the platysma muscle, in a routine manner. The shoulder is maintained in adduction over the trunk with an elastic bandage and sling, and a soft collar is applied to the neck.


59.8.4 Complications


Risks of the surgery include loss of preoperative muscle strength, injury to the phrenic nerve with diaphragmatic paralysis, cerebrospinal fluid leak, pneumothorax, thoracic duct injury (left-sided approach only), injury to the carotid and subclavian arteries or to the jugular and subclavian veins, pseudoarthrosis of the clavicle in the setting of clavicular osteotomy, and wound infection. Rarely, a wound hematoma or airway edema may result in respiratory compromise, and the patient must be monitored closely for evidence of airway insufficiency and swallowing dysfunction.


59.8.5 Postoperative Care


Most of our patients are discharged on postoperative day 2 or 3. The affected arm is immobilized in a sling for 3 weeks, at which point physical therapy is initiated to prevent joint stiffness and contractures. The patient is seen every 3 months in the clinic, and pain control is generally not a challenge when acetaminophen or ibuprofen is used. Other authors advocate the prolonged use of a cast placed in the operating room with subsequent use of a sling for several months before the initiation of physical therapy.


59.8.6 Outcomes


The results of surgery depend not only on the severity of the injury but also on the extent of root avulsions. Recovery typically begins within 2 to 10 months after surgical intervention and may continue until the patient is 5 years old. A 1995 report by Gilbert et al of 178 cases treated with nerve reconstruction showed excellent results for repairs in children who had Erb palsy with regard to shoulder and elbow function; in 54 children with global palsy, reinnervation of the lower trunk achieved useful finger flexion in 75% of cases.112 Multiple authors have demonstrated that neurologic improvement occurs in 75 to 95% of patients undergoing surgical reconstruction, with most achieving antigravity strength in the shoulder and/or elbow.29,​60,​79,​102,​113 Because the goal of surgery is not only to restore function but also to prevent permanent changes in the denervated muscle that may create long-term orthopedic deformities, the objectives include the following: stabilization of the shoulder through reinnervation of the supraspinatus and deltoid muscles, restoration of elbow flexion with reactivation of the biceps, and improvement of median nerve sensory function in cases of lower or total palsies in preparation for future secondary reconstruction procedures.114 Boome and Kaye published results including antigravity strength in 95% of the deltoid and 80% of the biceps muscles in patients following surgery; Laurent et al found that 85 to 95% of patients recovered antigravity strength above the elbow and noted a 50 to 70% recovery rate distal to the elbow.41,​58,​102 In our own series, those patients undergoing exploration and repair for upper plexus lesions achieved better results than those having surgery for lower plexus injuries.86


59.8.7 Secondary Reconstruction


Up to 35% of infants and children with chronic NBPP commonly experience specific secondary deformities at each joint due to the unopposed contraction of innervated muscle groups, the presence of joint contractures, and the occurrence of abnormal stressors affecting the upper limbs.8,​10 A review by Zancolli et al reported rates of secondary deformities of 72% for internal rotation contracture of the shoulder, 62% for flexion contracture of the elbow, 69% for supination contracture of the forearm, and 27% for ulnar deviation of the wrist and varying types of finger paralysis.115 Secondary reconstructions are often performed when such patients attain a rehabilitation plateau. The most common presentation is internal rotation contracture at the shoulder due to muscular imbalance between the active internal rotators and the paralyzed external rotators in patients with upper plexus injuries. Management by orthopedic surgeons includes serial clinical and radiologic assessments, muscle releases and muscle or tendon transfers, rotational osteotomies, and later shoulder arthrodesis. Grossman et al published their experience in infants aged 11 to 29 months with brachial plexus birth injuries. They used a late combined reconstruction of both the upper brachial plexus via end-to-side neurorrhaphies and the shoulder via subscapularis slides with or without glenohumeral joint reduction and capsulorrhaphies; their findings of improvement in all patients of at least two grades on a modified Gilbert scale suggest that some children presenting late with persistent neurologic deficits and concomitant shoulder deformities may benefit from this type of simultaneous treatment.116 Weakness of elbow flexion may be addressed with a bipolar latissimus dorsi pedicle muscle transfer or a functional muscle transfer performed in two stages. Extension deficit or elbow flexion contracture is also common and may be due to cross-innervation and muscle imbalance (stronger biceps than triceps) following spontaneous recovery from Erb palsy; because this is frequently observed in association with internal rotation contracture of the shoulder, surgical treatment of the shoulder deformity will typically improve the elbow contracture.117,​118 Additionally, joint splinting, muscle or tendon release, and extension osteotomy of the distal humerus may be necessary. The usual birth palsy forearm deformity of slight pronation does not require intervention because the hand is in a functional position; the supination posture seen in patients with global palsy, however, may require biceps tendon rerouting, interosseous membrane release, and rotational osteotomy of the radius or proximal radioulnar arthrodesis.119,​120 Finally, the lack of wrist extension in patients with upper plexus palsies is frequently reconstructed with a flexor carpi ulnaris or radialis muscle transfer; the wrist instability observed in some patients with total paralysis is treated with arthrodesis after skeletal maturity is achieved.121


59.9 Conclusion


Despite increased awareness of the etiology and risk factors and improved obstetric techniques, the incidence of birth-related brachial plexus palsy has not declined in recent years. Although many neonates with birth palsy attain spontaneous recovery within weeks of the occurrence, others fail to improve with conservative therapy. We favor a process of close and frequent follow-up in our multidisciplinary clinic, with a recommendation for surgery earlier than 3 months in cases of total plexus palsy. We have demonstrated that the motor examination at 3 months of age is predictive of a favorable outcome if antigravity strength of the deltoid, biceps, and triceps muscles is present; such patients are managed with physical therapy alone. Similarly, we have shown that strength testing at 6 months of age is predictive of a poor functional outcome if antigravity strength in the aforementioned muscle groups is not achieved; surgical intervention is recommended in these cases. Patient evaluation includes a detailed neurologic examination, chest radiography, EMG, and MR imaging of the cervical spine and brachial plexus. The surgical approach is tailored to each patient’s specific injuries, and repair strategies include neurolysis, neuroma resection and grafting, and nerve transfers; intraoperative electrophysiology may aid in the determination of the ideal reconstructive technique. We have recently used a decellularized peripheral nerve allograft in place of a sural nerve autograft with reduced operating time, a closer size match between graft and brachial plexus neural elements, and improved postoperative pain control due to the absence of leg incisions. The outcomes of primary brachial plexus reconstructions have been shown to be positive, with most patients making functional gains, particularly in the setting of upper trunk injuries. For those patients with chronic joint deformities due to unopposed muscle activity and contractures, secondary orthopedic surgery in the form of tendon releases, muscle transfers, osteotomies, or arthrodesis procedures may be necessary.




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Jul 16, 2016 | Posted by in NEUROSURGERY | Comments Off on Pediatric Brachial Plexus Palsy

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