Obstetrical Brachial Plexus Palsy

doi:10.1016/j.pediatrneurol.2007.09.013

Pediatric Neurology

Volume 38, Issue 4, April 2008, Pages 235-242

https://doi.org/10.1016/j.pediatrneurol.2007.09.013 Get rights and content

Obstetrical brachial plexus palsy, one of the most complex peripheral nerve injuries, presents as an injury during the neonatal period. The majority of the children recover with either no deficit or a minor functional deficit, but it is almost certain that some will not regain adequate limb function. These few cases must be managed in an optimal way. Considerable medical and legal debate has surrounded the etiologic factors of this traumatic lesion, and obstetricians are often considered responsible for the injury. According to recent studies, spontaneous endogenous forces may contribute substantially to this type of neonatal trauma. All obstetric circumstances that predispose to brachial plexus damage and that could be anticipated should be assessed. Correct diagnosis is necessary for the accurate estimation of prognosis and treatment. The most important aspect of therapy is timely recognition and referral, to prevent the various possible sequelae affecting the shoulder, elbow, or forearm. Since the early 1990s, research has increased the understanding of obstetrical brachial plexus palsy. Further research is needed, focused on developing strategies to predict brachial injury. This review focuses on emerging data relating to obstetrical brachial plexus palsy and discusses the present controversies regarding natural history, prognosis, and treatment in infants with brachial plexus birth palsies.

Introduction

Obstetrical brachial plexus palsy is defined as a flaccid paresis of an upper extremity due to traumatic stretching of the brachial plexus received at birth, with the passive range of motion greater than the active [1]. Obstetrical brachial plexus palsy results from injury to the cervical roots C₅-C₈ and thoracic root T₁[2], [3]. Although most injuries are transient, with full return of function occurring in 70-92% of cases [4], [5], [6], some result in prolonged and persistent disability [2], [7] and become major source of pregnancy-related medical litigation [8]. Until recently, many cases of brachial plexus palsies were subject to negligence suit, and expert medical witnesses and specialist lawyers had important ethical decisions to make.

The purpose of this review is to condense many of the current views and to highlight some reported evidence of developing knowledge and debate.

Section snippets

Terminology

Physicians who deal with this kind of injury have often proposed the use of the term birth brachial plexus palsy instead of obstetrical brachial plexus palsy. The suggested term reflects the pathophysiology of the injury, which is based on the position of the shoulder and head in relationship to the maternal pelvis, whereas obstetrical implies that the obstetrician is the cause of the palsy, a perception that could lead to confusion [9].

Other authors prefer the term congenital brachial palsy to

Incidence

There is wide variation in the rate of occurrence of obstetrical brachial plexus palsy among different epidemiological studies. The incidence ranges from 0.38 to 3 per 1000 live births in industrialized countries [3], [10], [11], [12]. The difference in incidence may depend on the type of obstetric care and the average birth weight of infants in different geographic regions [13], [14]. Improvements in obstetric technique have lowered the prevalence of obstetrical brachial plexus palsy to the

Risk Factors

The risk factors for brachial plexus palsies may be divided into three categories: neonatal, maternal, and labor-related factors (Table 1)[32].

The most significant risk factor cited in the literature is high birth weight (>4 kg) [25], [26]. Several studies have shown that increasing birth weight is strongly associated with an increasing risk of shoulder dystocia [33], [34], [35], [36], [37], [38].

Fetal position is also very important. Brachial injury occurs more frequently with breech

Pathophysiology of Obstetrical Brachial Plexus Injury

Obstetrical brachial plexus injury is generally considered to be caused by excessive traction applied to nerves [5]. This injury may result from shoulder dystocia, use of excessive or misdirected traction, or hyperextension of the arms in breech extraction [58].

The mechanics of the maternal pelvic size and the fetal shoulder size and position during the delivery process determine the injury to the brachial plexus. Typically, the anterior shoulder is involved when shoulder dystocia is present

Classification of Brachial Plexus Injuries: Clinical presentation

The brachial plexus is a group of nerves that includes the lower four cervical roots (C₅-C₈) and the first thoracic root (T₁). According to the severity, there are four types of nerve injuries: avulsion, rupture, neuroma, and neurapraxia [78], [79]. In terms of anatomical location, obstetrical brachial plexus palsies are divided into four categories [70], [80]: upper, intermediate, lower, and total plexus palsy.

Upper plexus palsy involves C₅, C₆, and sometimes C₇[81]. Also called Erb’s palsy,

Natural History

The majority (70-95%) of patients make complete spontaneous recovery [4], [89], [96], [97], [98]. There are many reported studies examining the natural history of neonatal brachial plexus palsy [2], [85], [99], some of which report recovery by 3 or 4 months of age [2], [100].

Both the extent (upper, lower, total) and the severity (avulsion, rupture) of the injury influence the prognosis. The upper plexus palsies are generally less severe [2], [100]. Poor prognostic factors include total [60] or

Physical Examination

Patients with birth brachial plexus palsies are, ideally, seen at a multidisciplinary clinic as soon as possible after birth. A history is taken, including obstetric history, mode of delivery, and postnatal health of the infant. All limbs should be examined for fractures and potential neurologic deficit, and a comprehensive examination of the entire body should identify any other injuries that may have occurred during delivery. Clinically observed asymmetry of chest wall expansion indicates

Investigations

Radiologic examination, electrophysiologic studies, and magnetic resonance imaging are useful in confirming clinical diagnosis and the extent of the injury in obstetrical brachial plexus palsy. X-rays of the chest, spine, and upper limbs are of utmost importance because they reveal associated injuries, such as rib, transverse process, clavicle, or humeral fractures [105]. Moreover, a chest X-ray is necessary to rule out phrenic nerve injury. Electrodiagnostic studies with electromyography and

Management

Treatment for a brachial plexus injury should be obtained as soon as possible from qualified, experienced medical professionals who specialize in treating brachial plexus injuries [4]. This multidisciplinary team of specialists ideally consists of a pediatrician, a pediatric neurologist, a neurosurgeon, a physical therapist, a pediatric orthopedic surgeon, a pediatric plastic surgeon, a neurophysiologist, an occupational therapist, and a social worker [4], [78].

In all cases of perinatal

Conclusions

Obstetrical brachial plexus palsy is a devastating complication of pregnancy and delivery, the incidence of which has remained stable over several decades. A variety of several risk factors contribute to the occurrence of obstetrical brachial plexus palsy, but the etiology remains to be fully elucidated. Persistent injury constitutes a significant proportion of obstetrically related medical litigation [3], [96]. There has been much legal debate over whether obstetricians are responsible for

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