Brachial plexopathy in infants after traumatic delivery: evaluation with MR imaging

Radiographic imaging modalities for perinatal brachial plexus palsy: a systematic review

PURPOSE

Perinatal brachial plexus palsy (PBPP) has a wide spectrum of clinical symptoms that can range from incomplete paresis of the affected extremity to flaccid arm paralysis. Although there is a high rate of spontaneous recovery within the first two years of life, it remains challenging to determine which patients will benefit most from surgical intervention. The diagnostic and predictive use of various imaging modalities has been described in the literature, but there is little consensus on approach or algorithm. The anatomic, pathophysiological, and neurodevelopmental characteristics of the neonatal and infant patient population affected by PBPP necessitate thoughtful consideration prior to selecting an imaging modality.

METHODS

A systematic review was conducted using six databases. Two reviewers independently screened articles published through October 2021.

RESULTS

Literature search produced 10,329 publications, and 22 articles were included in the final analysis. These studies included 479 patients. Mean age at time of imaging ranged from 2.1 to 12.8 months and investigated imaging modalities included MRI (18 studies), ultrasound (4 studies), CT myelography (4 studies), and X-ray myelography (1 study). Imaging outcomes were compared against surgical findings (16 studies) or clinical examination (6 studies), and 87.5% of patients underwent surgery.

CONCLUSION

This systematic review addresses the relative strengths and challenges of common radiologic imaging options. MRI is the most sensitive and specific for identifying preganglionic nerve injuries such as pseudomeningoceles and rootlet avulsion, the latter of which has the poorest prognosis in this patient population and often dictates the need for surgical intervention.

Diagnosis of closed injury and neoplasm of the brachial plexus by ultrasonography

PURPOSE

To evaluate the feasibility and accuracy of high-frequency sonography (US) in diagnosing traumatic brachial plexus (BP) lesions and neoplasms in the adult.

METHODS

Eleven patients with suspected BP closed trauma, 6 patients with BP neoplasm, and 12 healthy volunteers were scanned. The US findings were compared with surgical findings.

RESULTS

The interscalene space and intervertebral foramina were useful anatomic markers in identifying the BP. In the 24 sites examined in the normal group (12 subjects examined on both sides), the fifth to seventh cervical nerve roots (C5-7, including upper and middle trunk) were seen, whereas the eighth cervical and first thoracic nerve roots (C8, T1, including the lower trunk) were seen in 91.7% (22/24) of the subjects. The BP appeared as three or four discrete rounded hypoechoic nodules between the anterior scalene and middle scalene muscle in transverse views at the C5-7 level, representing the trunks in the sagittal oblique section. In the BP trauma group (n = 11), the normal nerve trunk was interrupted, and lesions were shown as thickening and swelling with indistinct inner structures. In the neoplasm group (n = 6), masses were shown as hypoechoic masses.

CONCLUSIONS

High-frequency US is valuable in diagnosing BP closed injuries and neoplasms.

The diagnostic value of CT myelography, MR myelography, and both in neonatal brachial plexus palsy

BACKGROUND AND PURPOSE

Although most infants with brachial plexus palsy recover function spontaneously, approximately 10-30% benefit from surgical treatment. Pre-operative screening for nerve root avulsions is helpful in planning reconstruction. Our aim was to compare the diagnostic value of CT myelography, MR myelography, and both against a surgical criterion standard for detection of complete nerve root avulsions in birth brachial plexus palsy.

MATERIALS AND METHODS

Nineteen patients who underwent a preoperative CT and/or MR myelography and subsequent brachial plexus exploration were included. Imaging studies were analyzed for the presence of abnormalities potentially predictive of nerve root avulsion. Findings of nerve root avulsion on surgical exploration were used as the criterion standard to assess the predictive value of imaging findings.

RESULTS

Ninety-five root levels were examined. When the presence of any pseudomeningocele was used as a predictor, the sensitivity was 0.73 for CT and 0.68 for MR imaging and the specificity was 0.96 for CT and 0.97 for MR imaging. When presence of pseudomeningocele with absent rootlets was used as the predictor, the sensitivity was 0.68 for CT and 0.68 for MR imaging and the specificity was 0.96 for CT and 0.97 for MR imaging. The use of both CT and MR imaging did not increase diagnostic accuracy. Rootlet findings in the absence of pseudomeningocele were not helpful in predicting complete nerve root avulsion.

CONCLUSIONS

Findings of CT and MR myelography were highly correlated. Given the advantages of MR myelography, it is now the single technique for preoperative evaluation of nerve root avulsion at our institution.

Differential diagnosis between pre- and postganglionic adult traumatic brachial plexus lesions by ultrasonography

The goal of this study was to prospectively investigate the feasibility of preoperative ultrasonography evaluation in the differentiation between pre- and postganglionic traumatic brachial plexus lesions. Two expert radiologists employed ultrasonography to observe the morphology of the brachial plexus in 23 patients with suspected traumatic brachial plexus lesions and 40 healthy volunteers. The detection rate was 100% (126/126) for the C5 through C7 nerve roots and upper and middle trunks and three fascicles, 84% (106/126) for the C8 roots and the lower trunks and 64% (81/126) for T1 roots in all subjects. Surgical inspections found 58 lesions in 23 patients (40 preganglionic lesions and 18 postganglionic lesions). Ultrasonography detected most of the brachial plexus lesions (56/58) but misjudged two preganglionic and two postganglionic lesions. The rate of differentiation was 93% (52/56). This study demonstrated that ultrasonography is a useful but experience-dependent supplemental imaging technique for preoperative diagnosis of brachial plexus lesions and differentiation between pre- and postganglionic brachial plexus lesions.

Neonatal trauma

A variety of traumatic lesions can occur during the neonatal period. Some of those lesions are clearly birth injuries due to delivery and others are caused by necessary procedures during intensive care in critically ill neonates. As usual patient history must be known and knowledge about the typical complications is necessary in order to select the appropriate imaging modality and thus enabling correct interpretation of those investigations by the radiologist. The purpose of this article is to present typical neonatal injuries, describe the underlying pathomechanisms and aetiology as well as the imaging findings.

Mechanical properties of spinal nerve roots subjected to tension at different strain rates

An understanding of the biomechanical and physiological properties of spinal nerve roots, particularly in response to tension, is critical in understanding the pathomechanisms of pain and nerve root injury and subsequent management of related injuries. Biomechanical properties of dorsal nerve roots at the lumbar and sacral levels were evaluated at various strain rates. Nerve roots were stretched at two different rates, 0.01 mm/s (Group A, quasistatic) and 15 mm/s (Group B, dynamic). Load, displacement and digital video data were obtained as the nerve roots were stretched until failure. Maximum stress, strain at maximum stress and modulus of elasticity (E) were calculated from the load-displacement measurements. Comparison of mechanical properties and failure patterns of nerve roots at two different rates revealed significant differences. Maximum load, maximum stress and E values of 5.7+/-2.7 gm, 257.9+/-111.3 kPa and 1.3+/-0.8 MPa were observed for Group A and 13.9+/-7.5 gm, 624.9+/-306.8 kPa and 2.9+/-1.5 MPa were observed for Group B, respectively. Higher maximum load, maximum stress and E values occurred at the dynamic stretch rate as compared to the quasistatic stretch rate, illustrating the strain-rate dependency of spinal nerve roots. No differences were observed in the strain values. Differences in mechanical behavior of nerve roots were also observed among the four root levels (L4-S1). A significant interaction effect was observed between nerve root diameter and stretch rates. Overall, results from the present study demonstrate viscoelastic material properties of spinal nerve roots and provide better insight on the tensile properties of nerve roots at different strain rates.

Complete recovery of spinal cord injury without radiographic abnormality and traumatic brachial plexopathy in a young infant falling from a 30-feet-high window

The laxity and elasticity of the infant or child spine may predispose him to cervical spine injury without bony disruption. The term 'SCIWORA' syndrome (Spinal Cord Injury Without Radiographic Abnormalities) is commonly used to characterize this condition. We report a 14-month-old infant who fell from a fourth-story window, with delayed onset of SCIWORA and brachial plexopathy. The infant initially presented with complete limb paralysis, but had a full recovery 6 months later. In contrast to the classical grave prognosis of these two conditions, our case represents one of the few exceptions in the literature with excellent recovery. Corresponding to previous reports, we suggest that the initial normal appearance of the spinal cord and nerve roots on magnetic resonance image may serve as a good prognosticator, regardless of the severity of initial neuroelectrophysiological studies or clinical manifestations.

Detection of Root Avulsion in the Dominant C7 Obstetric Brachial Plexus Lesion: Experience with Three-dimensional Constructive Interference in Steady-state Magnetic Resonance Imaging and Electrophysiology

OBJECTIVE:

Preoperative, reliable detection by ancillary investigations of spinal nerve root avulsions in infants with severe obstetric brachial plexus lesions to avoid ineffective operative repair from deceivingly intact but actually avulsed nerve roots.

METHODS:

Ten infants were selected with an infrequent, severe dominant C7 lesion, primarily because of the anatomically distinct supraclavicular course of this spinal nerve. Three-dimensional constructive interference in steady-state magnetic resonance imaging (3D CISS MRI) studies under mild sedation were performed and evaluated for detection of avulsed nerve roots by two experienced neuroradiologists. Preoperative electrodiagnostics (electromyography and somatosensory evoked potentials) as well as intraoperative somatosensory potentials and muscle contractions after electrostimulation were recorded. Preoperative and intraoperative ancillary investigations were correlated with intraoperative findings in eight patients and clinical status in two children who recovered spontaneously.

RESULTS:

Despite two minor motion artifacts, the quality of the 3D CISS MRI studies was good. In 8 of 10 patients, prediction of root continuity was consistent with operative or clinical findings, and 2 remained doubtful. Preoperative and intraoperative electrodiagnostics tended not to correlate with intraoperative findings in this small, selected group.

CONCLUSION:

3D CISS MRI provides good images of anterior and posterior spinal roots in infants with obstetric brachial plexus lesions. Images seem to allow accurate prediction of root avulsion in the majority of patients. In this study, electrodiagnostics were of limited value.

Update on management of pediatric brachial plexus palsy

This manuscript will review the literature and focus on the present controversies regarding natural history, microsurgical treatment, and secondary shoulder reconstructive surgery in infants with brachial plexus birth palsies. Surgical indications, expected outcomes and complications will be addressed. The controversy regarding microsurgery timing in extra-foraminal ruptures will be addressed in detail. The developments in assessment and care of glenohumeral deformity with magnetic resonance imaging scans, arthroscopic and open reductions, and tendon transfers about the shoulder will be discussed. Recommendations for microsurgery and shoulder reconstruction will be based on the present evidence from the literature.

Update on management of pediatric brachial plexus palsy

This manuscript will review the literature and focus on the present controversies regarding the natural history, microsurgical treatment, and secondary shoulder reconstructive surgery in infants with brachial plexus birth palsies. Surgical indications, expected outcomes, and complications will be addressed. The controversy regarding the timing of microsurgery in extraforaminal ruptures will be addressed in detail. The developments in assessment and care of glenohumeral deformity with magnetic resonance imaging scans, arthroscopic and open reductions, and tendon transfers about the shoulder will be discussed. Recommendations for microsurgery and shoulder reconstruction will be based on the present evidence from the literature.

MRI of rotator cuff muscle atrophy in relation to glenohumeral joint incongruence in brachial plexus birth injury

PURPOSE

To evaluate rotator cuff muscles and the glenohumeral (GH) joint in brachial plexus birth injury (BPBI) using MRI and to determine whether any correlation exists between muscular abnormality and the development of glenoid dysplasia and GH joint incongruity.

MATERIALS AND METHODS

Thirty-nine consecutive BPBI patients with internal rotation contracture or absent active external rotation of the shoulder joint were examined clinically and imaged with MRI. In the physical examination, passive external rotation was measured to evaluate internal rotation contracture. Both shoulders were imaged and the glenoscapular angle, percentage of humeral head anterior to the middle of the glenoid fossa (PHHA) and the greatest thickness of the subscapular, infraspinous and supraspinous muscles were measured. The muscle ratio between the affected side and the normal side was calculated to exclude age variation in the assessment of muscle atrophy.

RESULTS

All muscles of the rotator cuff were atrophic, with the subscapular and infraspinous muscles being most severely affected. A correlation was found between the percentage of humeral head anterior to the middle of the glenoid fossa (PHHA) and the extent of subscapular muscle atrophy (r(s)=0.45, P=0.01), as well as between its ratio (r(s)=0.5, P P=0.01). Severity of rotator cuff muscle atrophy correlated with increased glenoid retroversion and the degree of internal rotation contracture.

CONCLUSIONS

Glenoid retroversion and subluxation of the humeral head are common in patients with BPBI. All rotator cuff muscles are atrophic, especially the subscapular muscle. Muscle atrophy due to neurogenic damage apparently results in an imbalance of the shoulder muscles and progressive retroversion and subluxation of the GH joint, which in turn lead to internal rotation contracture and deformation of the joint.

The brachial plexus: normal anatomy, pathology, and MR imaging

The brachial plexus is the most technically and anatomically challenging area of the peripheral nervous system for diagnostic imaging. Marked improvements in spatial and contrast resolution of plexus images have resulted from the use of phased-array technology and newer MR pulse sequence designs. This article presents case material incorporating these improvements and discusses the primary factors that continue to limit MR image quality, such as inhomogenous fat suppression, motion artifacts, and small vessels that mimic or obscure plexus components, and potential solutions and imaging alternatives. Brachial plexus anatomy and its appearance on multiplanar MR images are reviewed. The morphologic features and MR signal characteristics that have been found useful in distinguishing between normal and abnormal plexus components,and in detecting neuropathic lesions, are addressed in the context of clinical indications for plexus imaging as follows: mass involving the plexus, traumatic injury, entrapment syndrome, posttreatment evaluation, and miscellaneous conditions.

The Surgical Treatment of Obstetric Brachial Plexus Palsy

Learning Objectives: After studying this article, the participant should be able to: 1. Understand the natural history of obstetric brachial plexus injury with an emphasis on clinicopathologic features. 2. Develop an awareness of the indications and timing for both nonsurgical and surgical treatment. 3. Acquire knowledge of the current methodologies involved in primary and secondary brachial plexus reconstruction.Obstetric brachial plexus palsy is a potentially devastating form of cervical nerve injury that occurs in 0.38 to 2.6 births per thousand. In this review, we discuss fundamental clinicopathology and delve into the indications and methods of both nonsurgical and surgical strategies. An analysis of the major techniques of reconstruction is placed within the context of historical trends and a contemporaneous survey of the literature. On this basis, and given our own 12-year experience (with 415 surgically treated patients), several general conclusions can be made: (1) Early surgical intervention (3 to 6 months) is essential to optimizing long-term outcome in patients who have not had return of function in critical muscle groups. At Texas Children’s Hospital, we have developed an efficient multidisciplinary approach to primary brachial plexus exploration and reconstruction by integrating the neurosurgical, physical medicine and rehabilitation, neurologic, and plastic surgical services. (2) Secondary residual deformities—most notably the quintessential internal rotation and adduction deformity of the upper extremity—arise from both prolonged conservative management and failed surgical treatment; however, an effective armamentarium of reconstructive options (tendon transfers, muscle releases, neurotizations, and free muscle flap transplantations) has evolved to markedly improve the functional status of these patients. (3) Innovative reconstructive approaches, including nerve grafting, intraplexal and extraplexal neurolysis, and nerve transfers, should be well planned and applied for maximal functional recovery of the extremity. Priorities for the restoration of hand function, elbow flexion, and shoulder abduction should be the goal.

Clinical assessment, MRI, and EMG in congenital brachial plexus palsy

Thirteen infants with congenital brachial plexus palsy (eight with upper, five with upper and lower) were monitored by magnetic resonance imaging (the first performed between 7 and 41 days of age and the second at 3 months of age), electromyography (the first performed between 27 and 50 days and the second at 3 months), and the muscle scoring system of the Hospital for Sick Children (at 3, 6, and 9 months of age). The findings were evaluated with respect to the clinical status of the patients at 12 months of age. Magnetic resonance imaging, which could be performed readily even in the neonatal period, revealed pseudomeningoceles in two of the five patients with a poor prognosis (in all planes even in the early days after birth) and in two of the eight patients with a good prognosis (more easily visible at 3 months of age). Electromyography implied root avulsion in three of five patients with a poor prognosis. Electromyography can be of great value for patients with a poor prognosis and root avulsion but may underestimate the severity. The muscle scoring system (Hospital for Sick Children) was determined to be the most predictive method for prognosis.

Emergency MR imaging of orthopedic trauma. Current and future directions

Fast MR imaging protocols pave the way for more widespread use of MR imaging to evaluate emergency room trauma patients. This article reviews technical developments and protocols facilitating rapid imaging, conventional applications of MR imaging to evaluate soft tissue injuries, and newer applications in which MR imaging is used to image both axial and appendicular fractures.

Obstetrical brachial palsy

Obstetrical brachial palsy (OBP) (also known in its various forms as Erb's palsy, Klumpke's paralysis, Erb-Duchenne palsy) complicates a very small proportion of births. Furthermore it seems likely that many cases recover with little in the way of remaining deficit but it is equally certain that some cases will not recover. There is increasing evidence that microsurgical help at an early stage can improve the prognosis in some cases. Scepticism exists about the role of surgery and many cases are referred too late for primary nerve surgery. Specialist surgical advice, specialist physiotherapy and where appropriate, either early nerve surgery or secondary reconstructive procedures at a later date can improve the condition of many of these children. This review condenses many of the current opinions and highlights areas of developing knowledge and debate.

Traction injuries of the brachial plexus: signal intensity changes of the posterior cervical paraspinal muscles on MRI

PURPOSE

Our goal was to evaluate MR signal intensity change of the posterior cervical paraspinal muscles in brachial plexus traction injuries to determine the value of this finding in the diagnosis of nerve root avulsion.

METHOD

MR images of 11 consecutive patients, 7 with nerve root avulsion and 4 without nerve root avulsion, were retrospectively analyzed, focusing on the signal intensity of the paraspinal muscles.

RESULTS

Among the seven patients with nerve root avulsion, T2- or T2*-weighted MR images showed increased signal intensity in the deep posterior paraspinal muscles in five and traumatic meningocele in four. The signal intensity of the posterior paraspinal muscles was normal in all patients without nerve root injuries.

CONCLUSION

MR signal intensity change in the deep posterior cervical paraspinal muscles is related to denervation and suggests the presence of nerve root avulsion.

Obstetrical brachial plexus injury in newborn babies delivered by caesarean section

The hand surgeon is frequently involved in the medicolegal assessment of birth palsy cases. Although brachial plexus injury has been reported in newborns delivered by Caesarean section, it is difficult to determine if these cases are due to excessive force when delivering the infant from the uterus or whether the palsy is related to other factors. We have studied our series of 16 cases of obstetrical brachial plexus palsy with special attention to the newborn baby delivered by Caesarean section. We have reviewed the English literature over the last decade and found that birth palsy in newborns delivered by Caesarean section is extremely rare (1% of all birth palsy cases). The differentiation between brachial plexus injury caused by forcible delivery and congenital upper limb palsy from other causes is discussed.

Klumpke's birth palsy. Does it really exist?

Erb's palsy is the most common obstetric brachial plexus injury followed by total plexus palsy. The distribution of Klumpke's birth palsy with modern obstetric practice is unknown. In this paper, we studied the distribution of Klumpke's birth palsy in our series of 235 consecutive cases of obstetrical brachial plexus injury and determined the incidence of this type of palsy to be 0.6% as cited in the English literature over the last decade.