Usefulness of myelography in brachial plexus injuries

Early MRI Can Predict the Indication for Surgery in Brachial Plexus Birth Injury: Results of the NAPTIME Study

BACKGROUND

Magnetic resonance imaging (MRI) has not been routinely used for infants with brachial plexus birth injury (BPBI); instead, the decision to operate is based on the trajectory of clinical recovery by 6 months of age. The aim of this study was to develop an MRI protocol that can be performed without sedation or contrast in order to identify infants who would benefit from surgery at an earlier age than the age at which that decision could be made clinically.

METHODS

This prospective multicenter NAPTIME (Non-Anesthetized Plexus Technique for Infant MRI Evaluation) study included infants aged 28 to 120 days with BPBI from 3 tertiary care centers. Subjects had nonsedated non-contrast rapid volumetric proton density MRI on 3-T scanners. Neuroradiologists at each site calculated the NAPTIME nerve root injury score for subjects at their site. Interrater reliability was performed on a subset of subjects. All of the subjects were evaluated with routine clinical examinations up to 6 months of age, by which time the treating surgeon determined whether to offer nerve surgery. Surgeons were blinded to the MRI results. The ability of the NAPTIME score to discriminate surgeon indication for surgery was evaluated using the receiver operating characteristic (ROC) curve, by estimating the area under the curve (AUC) across the range of NAPTIME scores.

RESULTS

Sixty-five infants successfully completed the NAPTIME MRI; 18 (28%) ultimately met the clinical criteria for nerve surgery. The interrater reliability for the NAPTIME score was moderate at 0.703 (95% confidence interval [CI], 0.582 to 0.818). The median NAPTIME score for subjects who met the criteria for nerve surgery was 16.2 (interquartile range [IQR], 9.9 to 18.9), while the median score for those who did not was 7.0 (IQR, 5.0 to10.5). The NAPTIME score predicted meeting the criteria for surgery with an AUC of 0.812 (95% CI, 0.688 to 0.936). A score of >13 offered a specificity of 0.94 and a sensitivity of 0.61 for surgical indication.

CONCLUSIONS

Non-contrast MRI without sedation is a useful tool in determining the severity of injury in BPBI. The NAPTIME score might distinguish which infants will meet the criteria for reconstructive nerve surgery earlier than when the decision can be made clinically.

LEVEL OF EVIDENCE

Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Clinical Application of Diffusion Tensor Imaging for a Brachial Plexus Injury

Brachial plexus injuries are commonly diagnosed clinically, as conventional imaging has a low sensitivity. In recent years, diffusion tensor imaging has established a clinical role in the study of the central nervous system and, while still presenting some limitations due to the technical complexity of the acquisition method, is showing promising results when applied to peripheral nerves. Moreover, deterministic fiber tracking with the Euler’s method and multishell acquisition are two novel advances in the field which contribute to enhancing the reliability of the technique reducing the respiratory and inhomogeneity artifacts in this “magnetically complex” region, and better isolating the fibers in a heterogeneous territory. Here, we report a case of brachial plexus traumatic injury, a healthy reference subject, and details on the acquisition protocol of the reconstruction algorithm.

Double Fascicular Transfer Using Partially Injured Donor Nerves: Is It Powerful Enough to Restore Elbow Flexion in Acute Brachial Plexus Injuries?

BACKGROUND

 Loss of elbow flexion is a common sequela of acute brachial plexus injuries (BPIs). The Mackinnon/Oberlin-II double fascicular transfer (DFT) is a widely used method to restore this function in acute C5-6 or C5-7 injuries. This study attempted to evaluate if this technique can be applied reliably for cases involving C8 and/or T1 injuries.

METHODS

 Adult patients with acute BPIs who underwent the Mackinnon/Oberlin-II DFT in our center between 2008 and 2018 were retrospectively identified. Group I (n = 37) included patients with only C5-6 or C5-7 injury, while group II (n = 32) patients presented C5-8 ± T1 injuries. The demographic data, pre- and postoperative neurologic evaluations, electrodiagnostic studies, and grip strength assessment were collected.

RESULTS

 A total of 69 patients met the inclusion criteria. Preoperatively, the patients in group II presented poorer nerve conduction and electromyography in both the median and the ulnar nerves and the supply muscles. The percentage of M3 achievement in both groups was 91.9 versus 87.5% and M4 was 73.0 and 71.9%, respectively, which both were not statically significant but the achievement of group II was slower than the group I, 1 to 2 months slower, respectively. Both groups had 57.57 and 46.0% of the postoperative grip power compared with the healthy side, the result of shoulder abduction was not different (p = 0.480).

CONCLUSION

 With careful preoperative evaluation, early intervention, appropriate intraoperative functional fascicle selection, and aggressive postoperative rehabilitation, indications for the Mackinnon/Oberlin-II DFT technique can safely include acute C5-8 injuries and even partial T1 acute BPIs.

Anatomy, Imaging, and Pathologic Conditions of the Brachial Plexus

The brachial plexus is an intricate anatomic structure with an important function: providing innervation to the upper extremity, shoulder, and upper chest. Owing to its complex form and longitudinal course, the brachial plexus can be challenging to conceptualize in three dimensions, which complicates evaluations in standard orthogonal imaging planes. The components of the brachial plexus can be determined by using key anatomic landmarks. Applying this anatomic knowledge, a radiologist should then be able to identify pathologic appearances of the brachial plexus by using imaging modalities such as MRI, CT, and US. Brachial plexopathies can be divided into two broad categories that are based on disease origin: traumatic and nontraumatic. In the traumatic plexopathy group, there are distinct imaging findings and management methods for pre- versus postganglionic injuries. For nontraumatic plexopathies, having access to an accurate patient history is often crucial. Knowledge of the timing of radiation therapy is critical to diagnosing post-radiation therapy brachial plexopathy. In acute brachial neuritis, antecedent stressors occur within a specific time frame. Primary and secondary tumors of the brachial plexus are not uncommon, with the most common primary tumors being peripheral nerve sheath tumors. Direct extension and metastasis from primary malignancies such as breast and lung cancer can occur. Although diagnosing a brachial plexus anomaly is potentially perplexing, it can be straightforward if it is based on foundational knowledge of anatomy, imaging findings, and pathologic features. ^©RSNA, 2020.

Is Pseudomeningocele an Absolute Sign of Root Avulsion Brachial Plexus Injury?

BACKGROUND

The finding of pseudomeningocele from cervical myelogram is widely accepted as a pathognomonic sign for diagnosing root avulsion in brachial plexus injury. In general, motor power in this setting should be absent. However, in clinical practice, we observed that motor power in some patients was still preserved. The objective of this study is to evaluate the accuracy of pseudomeningocele from cervical myelogram for predicting root avulsion in brachial plexus injury.

METHODS

We retrospectively reviewed 201 patients with brachial plexus injury from 2007-2011. Four patients were excluded due to open wound injury. Motor power of the key muscle of each nerve root was evaluated by skilled hand surgeons. All cervical myelogram was interpreted by radiologists. Sensitivities, specificities, positive predictive values and negative predictive values were calculated with 95% confidence interval.

RESULTS

Thirty and 29% of pseudomeningocele occurred at C7 and C8 level, respectively. The sensitivity of pseudomeningocele of each root from C5 to T1 was low (range, 10-62%). The specificity was high only at C5 (91%) and T1 (96.2%). Over 20% of patients with pseudomeningocele at C6-8 levels had some motor function. The initial muscle power of these patients was M1 or M2 and 70% of them recovered to at least M3 at the final follow-up.

CONCLUSIONS

Pseudomeningocele is not an absolute sign for diagnosing of root avulsion in brachial plexus injury due to its high false positive rate when compared with preoperative motor function of each root. Careful examination of the key muscle of each root is extremely crucial to prevent unnecessary operation on that cervical nerve root.

Brachial plexus injuries

Brachial Plexus Injuries result from a variety of causative mechanisms. They often present in a polytraumatic setting, and as such there is often a delay in their diagnosis and treatment. An understanding of the anatomy of the Brachial Plexus, and associated clinical pictures associated with injury, allows for early diagnosis and treatment. This review will consider the specific features of Brachial Plexus injuries relating to incidence, anatomy, mechanisms of injury, clinical presentation, and diagnostic evaluation.

Neonatal Magnetic Resonance Imaging Without Sedation Correlates With Injury Severity in Brachial Plexus Birth Palsy

PURPOSE

Which infants with brachial plexus birth palsy (BPBP) should undergo microsurgical plexus reconstruction remains controversial. The current gold standard for the decision for plexus reconstruction is serial clinical examinations, but this approach obviates the possibility of early surgical treatment. We hypothesize that a new technique using 3-dimensional volumetric proton density magnetic resonance imaging (MRI) without sedation can evaluate the severity of BPBP injury earlier than serial clinical examinations.

METHODS

Infants were prospectively enrolled prior to 12 weeks of age and imaged using 3 Tesla MRI without sedation. Clinical scores were collected at all visits. The imaging findings were graded based on the number of injured levels and the severity of each injury, and a radiological score was calculated. All infants were followed at least until the decision for surgery was made based on clinical examination.

RESULTS

Nine infants completed the MRI scan and clinical follow-up. The average Toronto score at presentation was 4.4 out of 10 (range, 0-8.2); the average Active Movement Scale score was 50 out of 105 (range, 0-86). Four infants required surgery: 2 because of a flail limb and Horner syndrome and 2 owing to failure to recover antigravity elbow flexion by age 6 months. Radiological scores ranged from 0 to 18 out of a maximum score of 25. The average radiological score for those infants who required surgery was 12 (range, 6.5-18), whereas the average score for infants who did not require surgery was 3.5 (range, 0-8).

CONCLUSIONS

Three-dimensional proton density MRI can evaluate spinal nerve roots in infants without the need for radiation, contrast agents, or sedation. These data suggest that MRI can help determine the severity of injury earlier than clinical examination in infants with BPBP, although further study of a larger sample of infants with varying severity of disease is necessary.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Non-Sedated Rapid Volumetric Proton Density MRI Predicts Neonatal Brachial Plexus Birth Palsy Functional Outcome

BACKGROUND AND PURPOSE

The current prognostic biomarker of functional outcome in brachial plexus birth palsy is serial clinical examination throughout the first 6 months of age. This can delay surgical treatment and prolong parental anxiety in neonates who will recover spontaneously. A potentially superior biomarker is a volumetric proton density MRI performed at clinical presentation and within the first 12 weeks of life, providing a high spatial and contrast resolution examination in 4 minutes.

METHODS

Nine neonates ranging in age from 4 to 9 weeks who presented with brachial plexus birth palsy were enrolled. All subjects underwent non-sedated 3 Tesla MRI with Cube Proton Density MRI sequence at the same time as their initial clinical visit. Serial clinical examinations were conducted at routine 4 week intervals and the functional performance scores were recorded. MRI findings were divided into pre-ganglionic and post-ganglionic injuries and a radiological scoring system (Shriners Radiological Score) was developed for this study.

RESULTS

Proton Density MRI was able to differentiate between pre-ganglionic and post-ganglionic injuries. Radiological scores (Shriners Radiological Score) correlated better with functional performance at 6 months of age (P = .022) than the initial clinical examinations (Active Movement Scale P = .213 and Toronto P = .320).

CONCLUSIONS

Rapid non-sedated volumetric Cube Proton Density MRI protocol performed at initial clinical presentation can accurately grade severity of brachial plexus birth palsy injury and predict functional performance at 6 months of age.

The Diagnostic Value of Intraoperative Measurement of Choline Acetyltransferase Activity During Brachial Plexus Surgery

We used the measurement of choline acetyltransferase (CAT) activity to distinguish between preganglionic and postganglionic injuries of the spinal roots during brachial plexus surgery. This study includes ten spinal roots in six patients with traumatic brachial plexus injuries. The results of CAT activity were compared with myelographic findings, the operative findings and the intraoperative evoked spinal cord potentials. The results of CAT activity and the operative findings were consistent in all roots. Whereas CAT activity in fascicles in preganglionic injured roots was below 500 cpm, it was above 2000 cpm in postganglionic injured roots. This study shows that intraoperative measurement of CAT activity can provide useful information on the site and severity of brachial plexus injuries and the assessment of the motor function status of the injured spinal root, both directly and quantitatively.

Brachial plexus injuries in adults: evaluation and diagnostic approach

The increased incidence of motor vehicle accidents during the past century has been associated with a significant increase in brachial plexus injuries. New imaging studies are currently available for the evaluation of brachial plexus injuries. Myelography, CT myelography, and magnetic resonance imaging (MRI) are indicated in the evaluation of brachial plexus. Moreover, a series of specialized electrodiagnostic and nerve conduction studies in association with the clinical findings during the neurologic examination can provide information regarding the location of the lesion, the severity of trauma, and expected clinical outcome. Improvements in diagnostic approaches and microsurgical techniques have dramatically changed the prognosis and functional outcome of these types of injuries.

Adult brachial plexus injury: evaluation and management

Adult traumatic brachial plexus injury involves injury of the C5-T1 spinal nerves. Common patterns of injury include "upper arm" and "total arm" types. The specific signs of preganglionic avulsion injury infer a poor prognosis for spontaneous recovery and surgery may be needed. Detailed preoperative evaluation is recommended for localization of the lesions. The treatment of upper arm type injury comprises restoration of elbow flexion and shoulder control. Good functional results may be achieved after multiple nerve transfers. The treatment of total arm type includes hand function reconstruction, in addition to shoulder and elbow treatment. Current options for hand function reconstruction include functioning free muscle transfers and nerve transfers.

Magnetic resonance imaging in brachial plexus injury

Brachial plexus injury represents the most severe nerve injury of the extremities. While obstetric brachial plexus injury has showed a reduction in the number of cases due to the improvements in obstetric care, brachial plexus injury in the adult is an increasingly common clinical problem. The therapeutic measures depend on the pathologic condition and the location of the injury: Preganglionic avulsions are usually not amenable to surgical repair; function of some denervated muscles can be restored with nerve transfers from intercostals or accessory nerves and contralateral C7 transfer. Postganglionic avulsions are repaired with excision of the damaged segment and nerve autograft between nerve ends or followed up conservatively. Magnetic resonance imaging is the modality of choice for depicting the anatomy and pathology of the brachial plexus: It demonstrates the location of the nerve damage (crucial for optimal treatment planning), depicts the nerve continuity (with or without neuroma formation), or may show a completely disrupted/avulsed nerve, thereby aiding in nerve-injury grading for preoperative planning. Computed tomography myelography has the advantage of a higher spatial resolution in demonstration of nerve roots compared with MR myelography; however, it is invasive and shows some difficulties in the depiction of some pseudomeningoceles with little or no communication with the dural sac.

Phrenic nerve palsy associated with brachial plexus avulsion in a pediatric patient with multitrauma

Although brachial plexus injury occurring during multitrauma is frequent in adults, it is rarely observed in childhood. The most common cause of pediatric traumatic brachial palsy is motor vehicle accidents followed by pedestrian struck. Generally, phrenic nerve palsy accompanying brachial plexus trauma is observed in 10% to 20% of cases, but it is overlooked because unilateral injuries are frequently asymptomatic. Severe unilateral phrenic nerve palsy accompanying brachial plexus avulsion is very rare. Here, we present a pediatric case of unilateral phrenic nerve palsy associated with respiratory distress and brachial plexus avulsion due to multitrauma.

Brachial plexus injury in adults: Diagnosis and surgical treatment strategies

Adult post traumatic Brachial plexus injury is unfortunately a rather common injury in young adults. In India the most common scenario is of a young man injured in a motorcycle accident. Exact incidence figures are not available but of the injuries presenting to us about 90% invole the above combination This article reviews peer-reviewed publications including clinical papers, review articles and Meta analysis of the subject. In addition, the authors' experience of several hundred cases over the last 15 years has been added and has influenced the ultimate text. Results have been discussed and analysed to get an idea of factors influencing final recovery. It appears that time from injury and number of roots involved are most crucial.

Imaging and electrodiagnostic work-up of acute adult brachial plexus injuries

Imaging and electrodiagnostic studies form an essential part of the evaluation of the patient with traumatic brachial plexopathy, enabling clarification of surgical options, prognostication of outcome and formulation of postoperative management. The primary objective of imaging is to identify pre-ganglionic injury indicative of nerve root avulsion. The presence of one or more nerve root avulsion injuries is a critical factor in surgical decision-making and the prognosis of surgical reconstruction. CT myelography is the current imaging modality of choice for this purpose. Initial electrodiagnostic (EDX) testing is ideally performed no sooner than 4 weeks following injury unless otherwise clinically indicated. Follow-up testing can be helpful at approximately 6 week intervals. The sensory nerve amplitudes are the most important component of nerve conduction testing in distinguishing between pre- and post-ganglionic injuries. Electromyographic studies will also assist in the determination of a pre- from post-ganglionic injury, the level of plexus involvement and identify potential donor nerves that may be suitable for use as transfers.

Obstetric brachial plexus injury

Obstetric brachial plexus injury (OBPI), also known as birth brachial plexus injury (BBPI), is unfortunately a rather common injury in newborn children. Incidence varies between 0.15 and 3 per 1000 live births in various series and countries. Although spontaneous recovery is known, there is a large subset which does not recover and needs primary or secondary surgical intervention. An extensive review of peer-reviewed publications has been done in this study, including clinical papers, review articles and systematic review of the subject. In addition, the authors' experience of several hundred cases over the last 15 years has been added and has influenced the ultimate text. Causes of OBPI, indications of primary nerve surgery and secondary reconstruction of shoulder, etc. are discussed in detail. Although all affected children do not require surgery in infancy, a substantial proportion of them, however, require it and are better off for it. Secondary surgery is needed for shoulder elbow and hand problems. Results of nerve surgery are very encouraging. Children with OBPI should be seen early by a hand surgeon dealing with brachial plexus injuries. Good results are possible with early and appropriate intervention even in severe cases.

Complications of intercostal nerve transfer for brachial plexus reconstruction

PURPOSE

Although numerous publications discuss outcomes of intercostal nerve transfer for brachial plexus injury, few publications have addressed factors associated with intercostal nerve viability or the impact perioperative nerve transfer complications have on postoperative nerve function. The purposes of this study were to report the results of perioperative intercostal nerve transfer complications and to determine whether chest wall trauma is associated with damaged or nonviable intercostal nerves.

METHODS

All patients who underwent intercostal nerve transfer as part of a brachial plexus reconstruction procedure as a result of injury were identified. A total of 459 nerves in 153 patients were transferred between 1989 and 2007. Most nerves were transferred for use in biceps innervation, free-functioning gracilis muscle innervation, or a combination of the two. Patient demographics, trauma mechanism, associated injuries, intraoperative nerve viability, and perioperative complications were reviewed.

RESULTS

Complications occurred in 23 of 153 patients. The most common complication was pleural tear during nerve elevation, occurring in 14 of 153 patients. Superficial wound infection occurred in 3 patients, whereas symptomatic pleural effusion, acute respiratory distress syndrome, and seroma formation each occurred in 2 patients. The rate of complications increased with the number of intercostal nerves transferred. Nerves were harvested from previously fractured rib levels in 50 patients. Rib fractures were not associated with an increased risk of overall complications but were associated with an increased risk of lack of nerve viability. In patients with rib fractures, intraoperative nerve stimulation revealed 148 of 161 nerves to be functional; these were subsequently transferred. In patients with preoperative ipsilateral phrenic nerve palsy, the risk of increased complications was marginally significant.

CONCLUSIONS

Brachial plexus reconstruction using intercostal nerves can be challenging, especially if there is antecedent chest wall trauma. Complications were associated with increasing numbers of intercostal nerves transferred. Ipsilateral rib fracture was adversely associated with intercostal nerve viability; it was not significantly associated with complication risk and should not be considered a contraindication to transfer. Preoperative phrenic nerve palsy was marginally associated with the likelihood of complications but not postoperative respiratory dysfunction when associated with intercostal nerve transfer.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Cervicothoracic intraspinal pseudomeningocele with cord compression after a traumatic brachial plexus injury

BACKGROUND CONTEXT

Pseudomeningoceles are noted within the neural foramen after avulsion plexus injuries. We present the case of a cervicothoracic epidural pseudomeningocele with spinal cord compression 18 years after a brachial plexus injury.

PURPOSE

To present a case report of a patient and literature review on cases with epidural pseudomeningoceles.

STUDY DESIGN

Case report and review of the literature.

METHODS

Retrospective review of the medical records of a patient presenting with an epidural pseudomeningocele after a plexus injury.

RESULTS

A 37-year-old male presented with neurological decline 18 years after sustaining a brachial plexus injury. Magnetic resonance tomography revealed an epidural fluid collection from C5 to T7 with significant spinal cord compression. Surgical intervention initially involved fenestration of the cyst and then rhizotomies of the C7 and C8 roots resulting in resolution of his new symptoms.

CONCLUSIONS

Pseudomeningoceles are common after brachial plexus avulsion injury and are usually stable, causing no symptoms, other than plexus neuropathies. We are unaware of previous reports of a patient with a traumatic brachial plexus avulsion who developed a large cervicothoracic, symptomatic, spinal, epidural, intracanalicular pseudomeningocele with cord compression 18 years after the initial injury. Patients with prior trauma and known plexus injuries with development of new neurological symptoms should be evaluated for the rare case of intradural pseudomeningoceles. Preoperative imaging with computed tomography myelography is important to isolate and definitively treat the fistulous connection.

Advanced radiological work-up as an adjunct to decision in early reconstructive surgery in brachial plexus injuries

BACKGROUND

As neurophysiologic tests may not reveal the extent of brachial plexus injury at the early stage, the role of early radiological work-up has become increasingly important. The aim of the study was to evaluate the concordance between the radiological and clinical findings with the intraoperative findings in adult patients with brachial plexus injuries.

METHODS

Seven consecutive male patients (median age 33; range 15-61) with brachial plexus injuries, caused by motor cycle accidents in 5/7 patients, who underwent extensive radiological work-up with magnetic resonance imaging (MRI), computed tomography myelography (CT-M) or both were included in this retrospective study. A total of 34 spinal nerve roots were evaluated by neuroradiologists at two different occasions. The degree of agreement between the radiological findings of every individual nerve root and the intraoperative findings was estimated by calculation of kappa coefficient (capital KA, Cyrillic-value). Using the operative findings as a gold standard, the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the clinical findings and the radiological findings were estimated.

RESULTS

The diagnostic accuracy of radiological findings was 88% compared with 65% for the clinical findings. The concordance between the radiological findings and the intraoperative findings was substantial (capital KA, Cyrillic = 0.76) compared with only fair (capital KA, Cyrillic = 0.34) for the clinical findings. There were two false positive and two false negative radiological findings (sensitivity and PPV of 0.90; specificity and NPV of 0.87).

CONCLUSIONS

The advanced optimized radiological work-up used showed high reliability and substantial agreement with the intraoperative findings in adult patients with brachial plexus injury.

Aspects cliniques, électroneuromyographiques et IRM des traumatismes du plexus brachial

OBJECTIVES

Management of traumatic lesions of the brachial plexus mainly depends on whether the injury is pre- (nerve root avulsion) or postganglionic (trunks and cords). The aim of this study was to assess the diagnostic and prognostic value of MRI in such lesions, and to determine any correlations among radiological, clinical and electroneuromyographical (EMG) data from both the initial and follow-up studies.

MATERIAL AND METHODS

Nine patients with acute traumatic lesions of the brachial plexus were investigated by MRI and EMG. Five further patients served as controls. The MRI protocol included fast spin-echo (FSE) T2-weighted and STIR sequencing. These scans were independently interpreted by two senior radiologists. Their findings were then validated during consensus meetings of surgeons, radiologists and neurologists to identify the exact localization and mechanism of each lesion, and to determine the advantages and drawbacks of each technique.

RESULTS

Among the nine patients, MRI scans were judged as normal in three whereas EMG showed distal lesions in two of them. In a further three patients, STIR MRI sequences demonstrated high signal intensities from the trunks and cords of C5 to T1. Among these three patients, MRI at three months showed persistence of these signal anomalies in one patient, and partial regression in the two others. In the remaining three patients, three-dimensional T2-weighted sequences showed nerve root avulsion, consistent with the initial EMG findings.

CONCLUSION

MRI is the best technique to demonstrate nerve root avulsion. However, unlike EMG, MRI does not allow visualization of distal lesions of the brachial plexus. Differentiation between edema (reversible) and demyelination (irreversible) of trunk and cord lesions remains difficult, and requires EMG or late MRI.

Computerized tomography myelography with coronal and oblique coronal view for diagnosis of nerve root avulsion in brachial plexus injury

Background

The authors describe a new computerized tomography (CT) myelography technique with coronal and oblique coronal view to demonstrate the status of the cervical nerve rootlets involved in brachial plexus injury. They discuss the value of this technique for diagnosis of nerve root avulsion compared with CT myelography with axial view.

Methods

CT myelography was performed with penetration of the cervical subarachnoid space by the contrast medium. Then the coronal and oblique coronal reconstructions were created. The results of CT myelography were evaluated and classified with presence of pseudomeningocele, intradural ventral nerve rootlets, and intradural dorsal nerve rootlets. The diagnosis was by extraspinal surgical exploration with or without spinal evoked potential measurements and choline acetyl transferase activity measurement in 25 patients and recovery by a natural course in 3 patients. Its diagnostic accuracy was compared with that of CT myelography with axial view, correlated with surgical findings or a natural course in 57 cervical roots in 28 patients.

Results

Coronal and oblique coronal views were superior to axial views in visualization of the rootlets and orientation of the exact level of the root. Sensitivity and specificity for coronal and oblique coronal views of unrecognition of intradural ventral and dorsal nerve root shadow without pseudomeningocele in determining pre-ganglionic injury were 100% and 96%, respectively. There was no statistically significant difference between coronal and oblique coronal views and axial views.

Conclusion

The information by the coronal and oblique coronal slice CT myelography enabled the authors to assess the rootlets of the brachial plexus and provided valuable data for helping to decide whether to proceed with exploration, nerve repair, primary reconstruction.

SPINAL CORD HERNIATION INTO ASSOCIATED PSEUDOMENINGOCELE AFTER BRACHIAL PLEXUS AVULSION INJURY

OBJECTIVE

Posttraumatic spinal cord herniation is a rare condition. We describe a case of spinal cord herniation into an associated pseudomeningocele after a brachial plexus avulsion injury.

CLINICAL PRESENTATION

A 33-year-old man began to develop progressive Horner's syndrome 14 years after a brachial plexus avulsion injury. At a clinical presentation 17 years after that injury, sensory disturbance and a unilateral pyramidal sign were also evident. In addition to myelography and computed tomographic myelography findings, coronal magnetic resonance imaging scans clearly demonstrated herniation of the spinal cord into a large pseudomeningocele inside the C7–T1 intervertebral foramen. Another pseudomeningocele inside the T1–T2 intervertebral foramen was also noted.

INTERVENTION

The patient underwent a C6–T2 laminectomy, during which the spinal cord was found to be herniated through a dural defect into a pseudomeningocele at the C8 root level, and a second dural defect was also shown, with an arachnoid outpouching that included an avulsed T1 root. The spinal cord herniation was reduced and the dural defects were repaired. After surgery, the patient showed no significant neurological changes, and his condition stabilized.

CONCLUSION

Brachial plexus root avulsions may result in the formation of pseudomeningoceles and can lead to spinal cord herniation. Coronal magnetic resonance imaging is useful to demonstrate spinal cord herniation as well as pseudomeningoceles. Surgical treatment is recommended for such cases with progressive symptoms to prevent further deterioration.

Brachial Plexus Injury: Clinical Manifestations, Conventional Imaging Findings, and the Latest Imaging Techniques

Brachial plexus injury (BPI) is a severe neurologic injury that causes functional impairment of the affected upper limb. Imaging studies play an essential role in differentiating between preganglionic and postganglionic injuries, a distinction that is crucial for optimal treatment planning. Findings at standard myelography, computed tomographic (CT) myelography, and conventional magnetic resonance (MR) imaging help determine the location and severity of injuries. MR imaging sometimes demonstrates signal intensity changes in the spinal cord, and enhancement of nerve roots and paraspinal muscles at MR imaging indicates the presence of root avulsion injuries. New techniques including MR myelography, diffusion-weighted neurography, and Bezier surface reformation can also be useful in the evaluation and management of BPI. MR myelography with state-of-the-art technology yields remarkably high-quality images, although it cannot replace CT myelography entirely. Diffusion-weighted neurography is a cutting-edge technique for visualizing postganglionic nerve roots. Bezier surface reformation allows the depiction of entire intradural nerve roots on a single image. CT myelography appears to be the preferred initial imaging modality, with standard myelography and contrast material-enhanced MR imaging being recommended as additional studies. Work-up will vary depending on the equipment used, the management policy of peripheral nerve surgeons, and, most important, the individual patient.

Adult traumatic brachial plexus injuries

Adult traumatic brachial plexus injuries are devastating, and they are occurring with increasing frequency. Patient evaluation consists of a focused assessment of upper extremity sensory and motor function, radiologic studies, and, most important, preoperative and intraoperative electrodiagnostic studies. The critical concepts in surgical treatment are patient selection as well as the timing and prioritizing of restoration of function. Surgical techniques include neurolysis, nerve grafting, neurotization, and free muscle transfer. Results are variable, but increased knowledge of nerve injury and repair, as well as advances in microsurgical techniques, allow not only restoration of elbow flexion and shoulder abduction but also of useful prehension of the hand in some patients.

Adult brachial plexus injuries: mechanism, patterns of injury, and physical diagnosis

Most brachial plexus injuries involve the entire plexus. An injury to major cords or branches often contains a mixed injury pattern, with portions of the nerve being avulsed, ruptured, or stretched. An advancing Tinel's sign implies the possibility of neurologic recovery; however, the surgeon should combine this physical finding with that of electrodiagnostic studies to assess the extent of nerve injury to allow for expedient surgical intervention when necessary.

Imaging the brachial plexus

Imaging the brachial plexus is challenging because of the complex anatomy of the region and the wide variety of pathology that can affect it. For the purpose of imaging, it is helpful to divide traumatic and nontraumatic entities affect-ing the brachial plexus. Improvements in imaging technology, including multidetector CT for CT myelography and the availability of full-field-strength MRI systems with fast gradients and dedicated surface coils for optimal spatial resolution, have led to more accurate prospective diagnoses and improved aid for neurosurgical planning for traumatic and nontraumatic brachial plexopathies. CT myelography is the current gold standard for the diagnosis of nerve root avulsions affecting the brachial plexus. MRI is the preferred modality for nontraumatic brachial plexopathy. Other modalities, such as US and PET, have a limited role in the evaluation of brachial plexus pathology. High-quality, high-resolution CT and MRI remain the mainstays for imaging the brachial plexus.

Planning brachial plexus surgery: treatment options and priorities

Brachial plexus injuries are devastating and usually result from high-energy trauma in young patients. Clinicians treating brachial plexus injuries need to recognize the pattern of injury presenting in each patient. Most injuries can be described as either supraclavicular or infraclavicular. The specific injury is determined by means ofa precise workup, including careful physical examination, electrodiagnostic studies, and imaging studies; a thorough workup is essential for successful preoperative planning. Priorities need to be identified and matched with available resources in each patient. A growing number of good treatment alternatives are available. Finally,counseling patients toward realistic expectations isa critical component of preparation for surgery.

Brachial plexopathies: classification, causes, and consequences

The brachial plexus, which is the most complex structure of the peripheral nervous system, supplies most of the upper extremity and shoulder. The high incidence of brachial plexopathies reflects its vulnerability to trauma and the tendency of disorders involving adjacent structures to affect it secondarily. The combination of anatomic, pathophysiologic, and neuromuscular knowledge with detailed clinical and ancillary study evaluations provides diagnostic and prognostic information that is important to clinical management. Since most brachial plexus disorders do not involve the entire brachial plexus but, rather, show a regional predilection, a regional approach to assessment of plexopathies is necessary.

Adult traumatic brachial plexus injury

Injury to the brachial plexus in the adult is usually a closed injury and the result of considerable traction to the shoulder. Brachial plexus injury in the adult is an increasingly common clinical problem. Recent advances in neurosurgical techniques have improved the outlook for patients with brachial plexus injuries. The choice of surgical procedure depends on the level of the injury and the radiologist has an important role in guiding the surgeon to the site of injury. This article will describe the anatomy and pathophysiology of traction brachial plexus injury in the adult. The neurosurgical options available will be described with emphasis on the information that the surgeon wants from imaging studies of the brachial plexus. The relative merits of MRI and CT myelography are discussed.

Accuracy of abnormal paraspinal muscle findings on contrast-enhanced MR images as indirect signs of unilateral cervical root-avulsion injury

PURPOSE

To evaluate the accuracy of abnormal magnetic resonance (MR) findings in the paraspinal muscles as indirect signs of nerve-root avulsion injury.

MATERIALS AND METHODS

Forty-three consecutive patients suspected of having unilateral root-avulsion injury underwent MR imaging and were evaluated. Paraspinal muscles were evaluated for abnormal signal intensity on T1- and T2-weighted images, abnormal enhancement on images obtained after contrast material enhancement, and muscle volume loss. MR images were interpreted independently by two observers for interobserver variability. MR findings were compared with findings of root continuity, determined with a combination of surgery and clinical evaluation. Sensitivities, specificities, and kappa values of the findings were calculated.

RESULTS

Sensitivities of MR findings in the paraspinal muscles indicating root-avulsion injury were 88% (36 of 41 patients) for abnormal enhancement, 83% (34 of 41 patients) for high signal intensity on T2-weighted images, 37% (15 of 41 patients) for high signal intensity on T1-weighted images, and 71% (29 of 41 patients) for muscle volume loss. Specificities for all findings were 100% (two of two patients). Of the paraspinal muscles, findings in the multifidus muscle were the most accurate and provided the highest interobserver agreement (kappa = 0.81).

CONCLUSION

Contrast material-enhanced abnormal MR findings in the paraspinal muscles are accurate in indicating root-avulsion injuries, and abnormal enhancement in the multifidus muscle is the most accurate among paraspinal muscle findings.

Cervical nerve root avulsion in brachial plexus injuries: magnetic resonance imaging classification and comparison with myelography and computerized tomography myelography

OBJECT

The authors describe a new magnetic resonance (MR) imaging technique to demonstrate the status of the cervical nerve roots involved in brachial plexus injury. They discuss the accuracy and reproducibility of a MR imaging-derived classification for diagnosis of nerve root avulsion compared with those of myelography combined with computerized tomography (CT) myelography.

METHODS

The overlapping coronal-oblique slice MR imaging procedure was performed in 35 patients with traumatic brachial plexus injury and 10 healthy individuals. The results were retrospectively evaluated and classified into four major categories (normal rootlet, rootlet injuries, avulsion, and meningocele) after confirming the diagnosis by surgical exploration with or without spinal evoked potential (EP) measurements and by referring to myelography and CT myelography findings. The reliability and reproducibility of the MR imaging-based classification was prospectively assessed by eight independent observers, and its diagnostic accuracy was compared with that of traditional myelography/CT myelography classification, correlated with surgical and spinal EP findings in another 50 cervical roots in 10 patients with traumatic brachial plexus injury.

CONCLUSIONS

In the retrospective study in which MR imaging and myelography/CT myelography findings involving 175 cervical roots in 35 patients were compared, the sensitivity of detection of the cervical nerve root avulsion was the same (92.9%) with both modalities. In the prospective study, interobserver reliability and intraobserver reproducibility showed that there was no statistically significant difference between MR imaging and myelography/CT myelography and that their accuracy for detecting cervical root avulsion was the same as that in the retrospective study. The overlapping coronal-oblique slice MR imaging technique is a reliable and reproducible method for detecting nerve root avulsion. The information provided by this modality enabled the authors to assess the roots of the brachial plexus and provided valuable data for helping to decide whether to proceed with exploration, nerve repair, primary reconstruction, or other imaging modalities.

Imaging of adult brachial plexus traction injuries

Closed, high-energy transfer traction injuries of the adult brachial plexus lead to rupture or avulsion of the spinal nerves. Accurate preoperative diagnosis is crucial for surgical planning and reconstruction. Myelography, computerised tomographic myelography and magnetic resonance imaging are the main radiological methods for preoperative diagnosis of the lesion. This article reviews the current status of imaging of traction injuries of the adult brachial plexus.

The surgical treatment of brachial plexus injuries in adults

Posttraumatic brachial plexus palsy is a severe injury primarily affecting young individuals at the prime of their life. The devastating neurological dysfunction inflicted in those patients is usually lifelong and creates significant socioeconomic issues. During the past 30 years, the surgical repair of these injuries has become increasingly feasible. At many centers around the world, leading surgeons have introduced new microsurgical techniques and reported a variety of different philosophies for the reconstruction of the plexus. Microneurolysis, nerve grafting, recruitment of intraplexus and extraplexus donors, and local and free-muscle transfers are used to achieve optimal outcomes. However, there is yet no consensus on the priorities and final goals of reconstruction among the various centers.

The role of magnetic resonance imaging in the management of traction injuries to the adult brachial plexus

Magnetic resonance imaging (MRI) of the cervical spine and brachial plexus was performed on 26 consecutive patients presenting with traction injuries of the brachial plexus during 1996 and 1997. These included T1 and T2 weighted coronal, sagittal and axial images of the cervical spine and coronal images of the brachial plexus. The results were compared with surgical findings, intraoperative neurophysiology, and subsequent clinical progress. Operations for exploration and repair have been performed in 23 and 26 patients scanned. Evidence of root avulsion was seen in 11 patients in the form of displacement or oedema of the spinal cord, haemorrhage or scarring within the spinal canal, absence of roots in the intervertebral foramena, and meningoceles. Characteristic abnormalities were evident in the MR scans of all cases where exploration confirmed some root avulsions. There were no false positives. MRI underestimated the number of individual roots avulsed; sensitivity was 81%. Post-ganglionic lesions were seen as swelling on T1 images associated with increasing signal on T2 images. It was usually possible to define the level of the injury within the plexus. This study suggests that MR imaging, performed early after traction injury to the brachial plexus, provides useful additional information towards establishing the level of the lesion. It also provides information about injury to the plexus outside the spinal canal.

Diagnosis of root avulsions in traumatic brachial plexus injuries: value of computerized tomography myelography and magnetic resonance imaging

Surgical management and prognosis of traction injuries of the brachial plexus depend on the accurate diagnosis of root avulsion from the spinal cord. Myelography, computerized tomography (CT) myelography, and recently magnetic resonance (MR) imaging have become the main radiological methods for preoperative diagnosis of cervical root avulsions. Most of the previous studies on the accuracy of CT myelography and MR imaging studies have correlated the radiological findings with the extraspinal surgical findings at brachial plexus surgery. Surgical experience shows that in many cases extraspinal findings diverge from intradural determinations. Consequently, only correlation with the intradural surgical findings will allow assessment of the factual accuracy of CT myelography and MR imaging studies. In a prospective study, 135 cervical roots (C5-8) were evaluated by CT myelography and/or MR imaging and further explored intradurally via a hemilaminectomy. The accuracy of the preoperative CT myelography-based diagnosis in relation to the intraoperative findings was 85%. On the other hand, MR imaging demonstrated an accuracy of only 52%. The most common reasons for false-positive or false-negative findings were: 1) partial rootlet avulsion; 2) intradural fibrosis; and 3) dural cystic lesions. Computerized tomography myelography scans using 1- to 3-mm axial slices prove to be the most reliable method to evaluate preoperatively the presence of complete or partial root avulsion in traumatic brachial plexus injuries. Because extradural judgment of cervical root avulsion can be unreliable, accurate assessment of intraspinal root avulsion enormously simplifies the decision concerning the choice of donor nerves for transplantation and/or neurotization during brachial plexus surgery.

Reconstruction of irreparable brachial plexus injuries with reinnervated free-muscle transfer. Case report

The complete avulsion of the brachial plexus is a severe injury usually caused by high-energy trauma. Even with the advent of modern microsurgical techniques, many patients have been rendered severely handicapped following this injury. The authors present a new reconstructive procedure that uses a microsurgical reinnervated free-muscle transfer to return prehensile function to an upper limb that is completely paralyzed. Although the procedure is still preliminary, a successful case is briefly described.

Restoration of sensibility in the hand after complete brachial plexus injury

Twenty-one patients with complete brachial plexus palsy due to the avulsion of multiple cervical nerve roots underwent motor and sensory reconstruction. Of these, 15 patients who had been followed for at least 2 years were included in the present study. Sensory reconstruction was performed by nerve graft or nerve crossing to the median nerve. The donor nerves included the supraclavicular nerve in 10 patients, the intercostal nerve in 3, and the C5 nerve root in the first 2 patients. Limited sensibility in the median nerve distribution of the hand was restored in 12 patients, and the results were classified as S2+ in 2, S2 in 4, S1 in 6, and S0 in 3, according to the S0 to S4 grading system. No moving two-point discrimination was restored in any case. While the best recovery obtained was only at the S2+ level, even this limited sensibility was useful for otherwise completely anesthetic patients.

Fast spin-echo magnetic resonance imaging for radiological assessment of neonatal brachial plexus injury

Neurosurgical management of birth-related brachial plexus palsy involves observing the patient for a period of several months. Operative intervention is usually undertaken at 3 to 6 months of age or more in infants who have shown little or no improvement in affected muscle groups. Ancillary tests such as electromyography and nerve conduction studies are occasionally useful. No radiological study has been consistently helpful in operative planning, except for contrast computerized tomography (CT) myelography, which requires general anesthesia in infants. This is because the infant's small size exceeds the functional resolution of the imaging modalities. This report describes the use of a special sequence of magnetic resonance (MR) imaging entitled "fast spin echo" (FSE-MR). Unlike CT myelography, this technique provides high-speed noninvasive imaging that allows clinicians to evaluate preganglionic nerve root injuries without the use of general anesthesia and lumbar puncture. The utility of this technique is illustrated in three cases, two involving either infraclavicular exploration or a combination of infraclavicular and supraclavicular exposure based on FSE-MR findings. The FSE-MR imaging offers an excellent alternative to contrast CT myelography in evaluation of infants with birth-related brachial plexus injuries.

Brachial plexus injury in Thailand: a report of 520 cases

Between October 1984 and October 1993, 520 patients with traumatic brachial plexus injuries were treated at the Department of Orthopaedic Surgery, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok. There were 486 male and 34 female patients. Eighty-two percent of the injuries were caused by motorcycle accidents, 9% by other traffic accidents, and 9% by gunshot, stabbing, and other means. The initial physical examination revealed 332 (63.8%) complete paralyses and 88 (36.2%) incomplete paralyses. One hundred twenty-seven patients were treated conservatively, 43 patients were observed before definitive treatment was given, and 350 patients were treated by operative means. Four hundred and twenty-one surgical procedures were performed, consisting of 314 neurotisations (250 spinal accessory, 14 plexo-plexal, 21 intercostal, 21 phrenic, 4 cervical plexus, 1 long thoracic, and 3 neuromuscular), 38 neurolyses, 23 nerve grafting, 16 free muscle transfers combined with neurotisations, and 30 musculotendinous transfers. Motor functional recovery of patients followed up for more than 2 years was evaluated. Nerve grafting gave 82% good (more than MRC grade 3) and 18% fair and poor recovery. Neurolysis gave 69% good and 31% fair and poor recovery. In patients with neurotisation, the spinal accessory (to suprascapular, axillary, and musculotaneous) intercostal (to musculotaneous), phrenic (to suprascapular, axillary, and musculocutaneous), and plexo- plexal methods gave a significant number of good results.

Clinical, electrophysiological, and myelographic studies of 9 patients with cervical spinal root avulsions: discrepancies between EMG and X-ray findings

In traumatic brachial plexus injuries a thorough neurological, electrodiagnostic, and radiological examination is essential to determine treatment and prognosis. The most important diagnostic question concerns the presence or absence of a preganglionic nerve root lesion. Electromyography and motor and sensory conduction studies were performed in 17 patients with traumatic plexus injuries who had myelographic evidence of nerve root avulsion; in 8 of these clinical and electrophysiological features confirmed the X-ray findings. However, in 9 cases there was a discrepancy between myelographic and neurophysiological data regarding the actual number and sites of roots avulsed. Thus, in 2 cases myelography showed avulsion of one more root than did conduction studies and EMG; in 2 others, there was discordance as to the specific roots avulsed; in 4 cases fewer nerve roots seem to be avulsed radiologically than predicted clinically, and in 1, none at all, although clinical and electrophysiological data were compatible with avulsion of four roots. In 6 cases recovery showed that avulsions indicated by clinical and electrophysiological considerations could not have occurred. When both EMG and myelography are misleading, surgical exploration should be considered.

The diagnostic value of MRI in traumatic brachial plexus injury

Findings in 34 patients with traumatic brachial plexus injury documented by surgical exploration and intra-operative somatosensory-evoked potentials were correlated with findings on myelography and magnetic resonance imaging (MRI) to determine whether MRI can identify nerve root avulsion. The coronal and sagittal planes were not able to demonstrate avulsion of the individual nerve roots. The axial and axial oblique planes did provide useful information to determine which nerve root was avulsed in the upper plexus, although it was difficult to clearly delineate the lower cervical rootlets. The accuracy of MRI was 73% for C5 and 64% for C6 and that of myelography 63% for C5 and 64% for C6. Thus, the diagnostic accuracy of MRI for upper nerve roots was slightly superior to myelography. Although its primary diagnostic value is limited to the upper nerve roots whose avulsion is relatively difficult to diagnose by myelography, MRI can provide useful guidance in the waiting period prior to surgical exploration after brachial plexus injury.

Clinical application of motorsensory differentiated nerve repair

Since 1979 acetylcholinesterase has been used in clinical practice for motor sensory differentiation. It was first used for median and ulnar nerve injuries at the wrist. Recently the application was extended to secondary nerve repair, including plexus reconstruction. The aim of this study was to present, for the first time, clinical results of motor sensory differentiated median and ulnar nerve repair and to show the advantage of this method in secondary repair. We compared a group of nine patients with motor sensory differentiated median and ulnar nerve repair with a group of 13 patients without motor sensory differentiation. Sensibility testing, strength measurements, and anatomical examinations were performed. The hand function was expressed in percentage values. Compound muscle action potentials and sensory antidromic conduction velocities were measured electroneurographically. Sensibility recovery was significantly better after motor sensory differentiated median nerve repair (P < 0.05). In secondary nerve repair acetylcholinesterase was used additionally for evaluating the level of resection of the proximal stump. The time required for perioperative histochemical differentiation has now been reduced to 2 hr.