Obstetrical brachial plexus palsy: lessons in functional neuroanatomy

A Systematic Review of the Tensile Biomechanical Properties of the Neonatal Brachial Plexus

Brachial plexus (BP) birth injury has a reported incidence of 1 to 4 per 1000 live births. During complicated deliveries, neonatal, maternal, and other birth-related factors can cause over-stretching or avulsion of the neonatal brachial plexus leading to injury. Understanding biomechanical responses of the neonate brachial plexus when subjected to stretch can offer insight into the injury outcomes while guiding the development of preventative maneuvers that can help reduce the occurrence of neonatal brachial plexus injuries. This review article aims to offer a comprehensive overview of existing literature reporting biomechanical responses of the brachial plexus, in both adults and neonates, when subjected to stretch. Despite the discrepancies in the reported biomechanical properties of the brachial plexus, available studies confirm the loading rate and loading direction dependency of the brachial plexus tissue. Future studies, possibly in vivo, that utilize clinically relevant neonatal large animal models can provide translational failure values of the biomechanical parameters for the neonatal brachial plexus when subjected to stretch.

The Relationship between Trunk Control and Upper Extremity Function in Children with Obstetric Brachial Plexus Palsy

PURPOSE

This study aimed to assess sitting skills and trunk control in children with obstetric brachial plexus palsy (OBPP) and investigate the effect of these skills on upper extremity function.

METHODS

A total of 106 children with OBPP aged 10-18 months were included in this study. Injury severity was determined with Narakas Classification. The Gross Motor Function Measurement Sitting Sub-scale was used to assess sitting skills, while the Sitting Assessment Scale was used to evaluate the trunk control. The upper extremity functions were assessed with using the Active Movement Scale and the Modified Mallet Score.

RESULTS

As the severity of injury increased, sitting skills and trunk control values decreased (p = .0001). In addition, upper extremity function decreased with the decreasing sitting skills and trunk control (p = .0001).

CONCLUSION

Rehabilitation approaches should involve approaches that aim to increase trunk control in addition to programs targeting the extremity function in children with OBPP.

A Systematic Review of the Electrodiagnostic Assessment of Neonatal Brachial Plexus

Despite improvements in obstetric care, neonatal brachial plexus palsy continues to significantly impact infants’ lives worldwide, with an incidence of 1 to 4 per 1000 live births. While a majority of affected infants recover spontaneously by three months, 20-30% suffer permanent functional deficits that significantly impair their quality of life. Anatomical complexity of the brachial plexus results in varying degrees of injury and pathological changes at multiple levels within the plexus. Current clinical diagnosis relies on electrodiagnostic techniques such as nerve conduction (i.e., motor and sensory) and electromyography studies. These techniques not only aid clinicians to differentiate between axonal and demyelinating lesions, evident by changes in signal shape and conduction, but also provide prognostic information in cases of brachial plexus injuries. The presented study offers a comprehensive review of existing literature on electrodiagnostic techniques employed for assessing neonatal brachial plexus injuries.

Fifth Lumbar L5 Perineural Cyst with Unusual Radiculopathy: Traction Plexopathy

Perineural cysts are cystic dilations and are frequently seen in relation to the lumbosacral spine. We describe a case of a fifth lumbar (L5) perineural cyst with unusual radicular symptoms and discuss the possible role of traction plexopathy caused by the cyst. A 38-year-old male presented with a longstanding history of back pain and right side thigh pain. This pain radiated from the buttocks to the lateral and anterior aspect of the thigh. He described the pain as pins and needles/burning with no significant relief with medications or rest. Imaging of the lumbar spine revealed a cystic lesion on the right side involving the L5 nerve root in the foraminal region. He failed conservative treatment and elected to have the cyst removed even with a guarded prognosis. A wide L5 laminectomy was performed. Due to the size of the cyst which was causing traction on the exiting L5 nerve root, the L5 pedicle was excised in order to delineate the cyst and to prevent any iatrogenic injury to the root. The patient had the dramatic improvement in his radicular pain immediately after the surgery and continues to be pain-free at his latest three-year follow-up. This case highlights the unusual pain pattern distribution from a perineural cyst possibly secondary to traction effect of the tumor.

Obstetrical Brachial Plexus Palsy

Obstetrical brachial plexus palsy is a disorder of the peripheral nervous system and occurs in as many as 0.4% of infants born. It is associated with shoulder dystocia, use of mechanical extraction, and macrosomia; it occurs more frequently in infants born by vaginal delivery. The unilateral injury to the brachial plexus complex occurs during the delivery phase as lateral traction is applied to the head to permit shoulder clearance. The infant typically presents in the delivery room with decreased active movements of the affected arm and asymmetrical primitive reflex responses. The severity of nerve involvement can range from a stretch injury to complete avulsion. While full recovery is possible, prognosis is variable and up to 35% of children may have some degree of life-long functional impairment of the affected limb.

The implications of injury in the developing nervous system on upper extremity function

STUDY DESIGN

Literature review.

PURPOSE

The corticospinal system (CS) and peripheral nervous system (PNS) are common sites of damage during the early stages of life. The prenatal or immediately prenatal period is the most common time for damage to occur. Here we briefly review the basic features of the development of the CS and the PNS and the clinical consequences of injury to or improper development of these systems on upper extremity (UE) function.

RESULTS

The proper development of both the CS and PNS is necessary to achieve adequate function of the (UE). Injury or improper development of these systems can lead to upper extremity dysfunction and limit participation in activities of daily living.

CONCLUSIONS

Both the PNS and CS play major roles in the proper functioning of the UE. A better understanding of their roles and common developmental disorders is needed to move rehabilitation of motor impairments forward.