Brachial plexopathies: classification, causes, and consequences

Brachial Plexus Injury Influences Efferent Transmission on More than Just the Symptomatic Side, as Verified with Clinical Neurophysiology Methods Using Magnetic and Electrical Stimulation

The variety of sources of brachial plexus injuries (BPIs) and the severity and similarity of their clinical symptoms with those of other injuries make their differential diagnosis difficult. Enriching their diagnosis with objective high-sensitivity diagnostics such as clinical neurophysiology may lead to satisfactory treatment results, and magnetic stimulation (MEP) might be an advantageous addition to the diagnostic standard of electrical stimulation used in electroneurography (ENG). The asymptomatic side in BPI cases sometimes shows only subclinical neurological deficits; this study aimed to clarify the validity and utility of using MEP vs. ENG to detect neural conduction abnormalities. Twenty patients with a BPI and twenty healthy volunteers with matching demographic and anthropometric characteristics were stimulated at their Erb's point in order to record the potentials evoked using magnetic and electrical stimuli to evaluate their peripheral motor neural transmission in their axillar, musculocutaneous, radial, and ulnar nerves. MEP was also used to verify the neural transmission in participants' cervical roots following transvertebral stimulations, checking the compatibility and repeatability of the evoked potential recordings. The clinical assessment resulted in an average muscle strength of 3-1 (with a mean of 2.2), analgesia that mainly manifested in the C5-C7 spinal dermatomes, and a pain evaluation of 6-4 (mean of 5.4) on the symptomatic side using the Visual Analog Scale, with no pathological symptoms on the contralateral side. A comparison of the recorded potentials evoked with magnetic versus electrical stimuli revealed that the MEP amplitudes were usually higher, at p = 0.04-0.03, in most of the healthy volunteers' recorded muscles than in those of the group of BPI patients, whose recordings showed that their CMAP and MEP amplitude values were lower on their more symptomatic than asymptomatic sides, at p = 0.04-0.009. In recordings following musculocutaneous and radial nerve electrical stimulation and ulnar nerve magnetic stimulation at Erb's point, the values of the latencies were also longer on the patient's asymptomatic side compared to those in the control group. The above outcomes prove the mixed axonal and demyelination natures of brachial plexus injuries. They indicate that different types of traumatic BPIs also involve the clinically asymptomatic side. Cases with predominantly median nerve lesions were detected in sensory nerve conduction studies (SNCSs). In 16 patients, electromyography revealed neurogenic damage to the deltoid and biceps muscles, with an active denervation process at work. The predominance of C5 and C6 brachial plexus injuries in the cervical root and upper/middle trunk of patients with BPI has been confirmed. A probable explanation for the bilateral symptoms of dysfunction detected via clinical neurophysiology methods in the examined BPI patients, who showed primarily unilateral damage, maybe the reaction of their internal neural spinal center's organization. Even when subclinical, this may explain the poor BPI treatment outcomes that sometimes occur following long-term physical therapy or surgical treatment.

Emotion Processing in Peripheral Neuropathic Pain: An Observational Study

BACKGROUND

In clinical practice, the implementation of tailored treatment is crucial for assessing the patient's emotional processing profile. Here, we investigate all three levels of analysis characterizing emotion processing, i.e., recognition, representation, and regulation, in patients with peripheral neuropathic pain (PNP).

METHODS

Sixty-two patients and forty-eight healthy controls underwent quantitative sensory testing, i.e., psychophysical tests to assess somatosensory functions such as perception of cold (CDT), heat-induced pain (HPT), and vibration (VDT), as well as three standardized tasks to assess emotional processing: (1) the Ekman 60-Faces Test (EK-60F) to assess recognition of basic facial emotions, (2) the Reading the Mind in the Eyes Test (RME) to assess the ability to represent the feelings of another person by observing their eyes, and (3) the 20-item Toronto Alexithymia Scale (TAS-20) to assess emotional dysregulation, i.e., alexithymia.

RESULTS

General Linear Model analysis revealed a significant relationship between left index finger VDT z-scores in PNP patients with alexithymia. The RME correlated with VDT z-scores of the left little finger and overall score for the EK-60F.

CONCLUSIONS

In patients with PNP, emotion processing is impaired, which emphasizes the importance of assessing these abilities appropriately in these patients. In this way, clinicians can tailor treatment to the needs of individual patients.

Brachial Plexus Injury Secondary to Spontaneous Upper Limb Haematoma

Spontaneous upper limb muscle haematomas are rare clinical phenomenons, which often go under- or misdiagnosed. They can present management challenges in the context of anticoagulant therapy, especially in the presence of other medical conditions. We present the case of a 52-year-old male with an initially missed presentation of a spontaneous muscle haematoma that progressed and re-presented to the emergency department (ED) with signs of mixed upper limb neuropathy requiring surgical evacuation and an emergency fasciotomy. This case highlights the importance of prompt diagnosis and intervention. While brachial plexus injuries from haematoma compression are uncommon, in our case, we discuss the need for surgical intervention to relieve pressure and optimise patient outcomes when clinically concerned about compartment syndrome or progressive neuropathy.

Recent advances in neuroanatomy: the myotome update

The myotome of a muscle is the basis for diagnosing spinal and peripheral nerve disorders. Despite its critical importance in clinical neurology, myotome charts presented in many textbooks, surprisingly, show non-negligible discordances with each other. Many authors do not even clearly state the bases of their charts. Studies that have presented with raw data regarding myotome identification are rather rare. A classic study in the 19th century that pursued the nerve course in cadavers still has a substantial influence on existing charts, despite its definite limitations. Other scarce studies in humans include identification by root stimulation during surgery, clinical observations in root avulsion or spinal cord injury and clinical and electromyographical investigations in patients with single radiculopathies or certain plexopathies. A few recent studies have proposed new theories regarding the myotomes of some muscles. T1 innervation of the median intrinsic hand muscles is a typical example. We have added a number of new findings, such as T1 innervation of the forearm flexor muscles innervated by the median nerve except the pronator teres and flexor carpi radialis, C5 innervation of the brachioradialis, and two C6 indicator muscles, pronator teres and extensor carpi radialis brevis. Increased accuracy of the myotome charts will improve the localisation in neurology.

Diagnostic Uncertainty in Cervical Radiculopathy

Cervical radiculopathy is defined as a pathological process affecting the cervical nerve root(s). While not an uncommon entity, this report describes a case of cervical radiculopathy in an active duty Marine with unique features to include the C5 nerve root as the primary point of injury with corresponding severe motor weakness that warranted expedited workup. This expedited workup included early referral to Neurology for nerve conduction and electromyography (EMG) studies that were ultimately diagnostic in the setting of equivocal Magnetic Resonance Imaging findings. This highlight of this case is the demonstration of the utility of EMG in cervical radiculopathy evaluation, which aided in an efficient and effective treatment course. We contend that in cases of cervical radiculopathy with a focal deficit of profound weakness with shoulder abduction and elbow flexion, obtaining nerve conduction studies and EMGs within the first 4 to 6 weeks of presentation should be viewed as essential for the long-term recovery and effective management of the injured service member, particularly when injury to the upper trunk of the brachial plexus can also account for these specific motor deficits. This report will cover a brief review of the pathophysiology, evaluation, and natural history of cervical radiculopathy with special attention paid to the timing and efficacy of EMG.

Acute Radial Compressive Neuropathy: The Most Common Injury Induced by Japanese Rope Bondage

Japanese rope bondage (RB), or Shibari, is an art form involving the voluntary and aesthetic binding of a person with a rope, which may result in compression injuries to peripheral nerves. To investigate the nature and extent of nerve injuries associated with this practice, we conducted a survey of four experienced RB practitioners (riggers) and participants who were willing to share their experiences of injury. Injuries presented acutely and immediately following full-body suspensions, with a total of 10 individuals (16 injuries) identified with damage to the radial, axillary, or femoral nerves. Notably, the radial nerve was the most commonly affected structure in our patient cohort, with 90.0% of individuals experiencing an injury at this level. We present a rare case of acute repeated compression of the radial nerve during full-body suspension RB. A 29-year-old female was suspended for 25 minutes using a 6-mm jute rope, resulting in wrist and finger drop, as well as reduced sensation in the left hand. Analysis revealed a 77.3% conduction block in the upper arm segment. Improvement was observed after three months, fully achieved after five months. Seventeen months later, re-compression of both radial nerves occurred during a similar suspension lasting 8-10 minutes. Improvement occurred after one week, fully achieved after four weeks. The third compression episode occurred three years later, lasting five minutes, with full recovery within two minutes. This study focuses on the injury of peripheral nerves, including the radial, axillary, and femoral nerves, namely, acute compression neuropathy induced by Japanese RB. Because the radial nerve is the most frequently injured structure, the findings underscore the significance of recognizing the anatomical course of the radial nerve, particularly its position posteriorly at the distal deltoid tuberosity level, as a means of preventing nerve injury in this region. This knowledge is particularly crucial for individuals engaged in the practice of RB, emphasizing the importance of taking precautions to avoid potential nerve damage.

Neurophysiological Evaluation of Neural Transmission in Brachial Plexus Motor Fibers with the Use of Magnetic versus Electrical Stimuli

The anatomical complexity of brachial plexus injury requires specialized in-depth diagnostics. The clinical examination should include clinical neurophysiology tests, especially with reference to the proximal part, with innovative devices used as sources of precise functional diagnostics. However, the principles and clinical usefulness of this technique are not fully described. The aim of this study was to reinvestigate the clinical usefulness of motor evoked potential (MEP) induced by a magnetic field applied over the vertebrae and at Erb's point to assess the neural transmission of brachial plexus motor fibers. Seventy-five volunteer subjects were randomly chosen to participate in the research. The clinical studies included an evaluation of the upper extremity sensory perception in dermatomes C5-C8 based on von Frey's tactile monofilament method, and proximal and distal muscle strength by Lovett's scale. Finally, 42 healthy people met the inclusion criteria. Magnetic and electrical stimuli were applied to assess the motor function of the peripheral nerves of the upper extremity and magnetic stimulus was applied to study the neural transmission from the C5-C8 spinal roots. The parameters of compound muscle action potential (CMAP) recorded during electroneurography and MEP induced by magnetic stimulation were analyzed. Because the conduction parameters for the groups of women and men were comparable, the final statistical analysis covered 84 tests. The parameters of the potentials generated by electrical stimulus were comparable to those of the potentials induced by magnetic impulse at Erb's point. The amplitude of the CMAP was significantly higher following electrical stimulation than that of the MEP following magnetic stimulation for all the examined nerves, in the range of 3-7%. The differences in the potential latency values evaluated in CMAP and MEP did not exceed 5%. The results show a significantly higher amplitude of potentials after stimulation of the cervical roots compared to potentials evoked at Erb's point (C5, C6 level). At the C8 level, the amplitude was lower than the potentials evoked at Erb's point, varying in the range of 9-16%. We conclude that magnetic field stimulation enables the recording of the supramaximal potential, similar to that evoked by an electric impulse, which is a novel result. Both types of excitation can be used interchangeably during an examination, which is essential for clinical application. Magnetic stimulation was painless in comparison with electrical stimulation according to the results of a pain visual analog scale (3 vs. 5.5 on average). MEP studies with advanced sensor technology allow evaluation of the proximal part of the peripheral motor pathway (between the cervical root level and Erb's point, and via trunks of the brachial plexus to the target muscles) following the application of stimulus over the vertebrae.

Case report: Brachial plexopathy caused by malignant peripheral nerve sheath tumor and review of the literature

Brachial plexopathy (BP) is easily misdiagnosed due to its complexity and varying clinical presentation. Malignant peripheral nerve sheath tumors (MPNST) can accumulate in the brachial plexus and share symptoms with BP, which may hinder the differential diagnosis between BP induced by radiation or metastases, and MPNST-derived BP, in patients with a history of breast cancer and radiation exposure. A 34-year-old Chinese female presented with MPNST. The tumor involved the brachial plexus. She had a history of breast cancer and radiotherapy. The first consideration was radiation- or breast cancer metastasis-derived BP. Clinical examination was performed. Finally, a diagnosis of MPNST of the brachial plexus was made, which guided an accurate treatment plan. This report highlights the importance of correctly diagnosing BP etiology for guiding precise treatment. BP caused by MPNST needs to be considered in clinical practice, and biopsy plays a central role in the differential diagnosis. Complete local surgical resection can prolong survival of patients with MPNST and improve treatment prognosis.

Neuromuscular electrodiagnosis

The electrodiagnostic (EDX) study is an extension of the clinical examination, which means that the clinical features dictate the initial nerve conduction studies (NCS) performed. However, once the EDX study is started, it continues in an independent manner, meaning that the initial NCS findings dictate the subsequent studies performed. Because competent EDX study performance requires considerable knowledge (and special training), it is not possible to convey all of the basic and advanced concepts in a single chapter. Nonetheless, the most important concepts are easily conveyed by a discussion limited to EDX-pertinent anatomical, physiological, pathological, pathophysiological, and basic electrical concepts. The focus of this chapter will be on the standard NCS and needle EMG measurements made during EDX studies and their significance with regard to lesion localization and characterization. Because the most challenging portion of EDX study is motor unit action potential analysis, this topic is more extensively reviewed. The utility of the sensory NCS for identifying focal axon loss, the utility of the motor NCS for screening long nerve segments for focal demyelination and for determining lesion severity, and the utility of the needle EMG for confirming the NCS findings, better defining lesion localization, and identifying the temporal features (e.g., chronicity) and rate of progression of the lesion are also reviewed.

The effects of melatonin in the treatment of acute brachial plexus compression injury in rats

Introduction

Brachial plexus injury (BPI) is one of the most destructive peripheral nerve injuries and there is still a lack of effective treatment.

Methods

This study was conducted to evaluate the effects of melatonin in the treatment of acute brachial plexus compression injury in rats using histopathological, histomorphometric, immunohistochemical and electrophysiological methods. Forty-eight adult male Sprague Dawley rats were randomly allocated into three groups: sham, melatonin and vehicle groups. The brachial plexus compression injury model was performed by a vascular clamp. Melatonin group received intraperitoneal injection of melatonin at doses of 10 mg/kg for 21 days after crush injury. The conduction velocity and amplitude of compound muscle action potential (CAMP) in the regenerated nerve, and nerve histomorphometry, as well as levels of myelin protein zero (P0) protein of the crush region were assessed.

Results

Compared with the vehicle group, the melatonin group which reported significant increased CMAP conduction velocity and amplitude also showed thicker myelin sheath and lower levels of P0 protein.

Discussion

Our results suggest that melatonin effectively promotes nerve regeneration and improves the function of damaged nerves. Melatonin treatment is a promising strategy for the treatment of acute brachial plexus compression injury.

Outcome of Nerve Grafting for Radiation-Induced Brachial Plexopathy

BACKGROUND

There is no consensus on the optimal treatment for radiation-induced brachial plexopathy (RIBP).

OBJECTIVE

To present our experience of using nerve resection and autografting as a treatment strategy for this challenging condition.

METHODS

From September 2014 to January 2020, 8 patients with RIBP were treated with segmental nerve resection and autografting, with or without other supplementary procedures. All patients underwent sural nerve grafting to the musculocutaneous nerve. All were female with a mean age of 53 (range 38-64) years. Seven were on the left, and 1 was on the right. The mean follow-up duration was 33 (range 17-72) months.

RESULTS

By the final review, 7 of 8 patients regained at least antigravity elbow flexion. Four patients reached Medical Research Council (MRC) grade 4, 3 MRC grade 3, and MRC grade 2 recovery in the biceps. The mean Visual Analog Score for pain improved from 2.6 preoperatively to 0.6 postoperatively ( P = .042).

CONCLUSION

Nerve resection and autografting may restore satisfactory elbow flexion in patients with RIBP.

Brachial Plexopathy After Single-Fraction Stereotactic Body Radiation Therapy in Apical Lung Tumors

PURPOSE

The objective of this study was to evaluate the incidence of brachial plexus injury (BPI) after single-fraction stereotactic body radiation therapy (SBRT) to apical lung tumors.

METHODS AND MATERIALS

A retrospective cohort analysis was performed of all patients treated with single-fraction lung SBRT at our institution from 2007 to 2022. Apical tumors were identified as those with an epicenter located above the arch of the aorta. Dosimetric analysis of dose to the brachial plexus (BP) was done using both the subclavian vessel (SCV) surrogate structure and anatomic BP. BPI was assessed per Common Terminology Criteria for Adverse Events, version 4.0, as regional paresthesia, marked discomfort and muscle weakness, and limited movement of the arm or hand.

RESULTS

A total of 45 patients met inclusion criteria with median follow-up of 21 months. There were 9 patients who exceeded the BP dose constraint using the SCV or anatomic BP volume. Only 1 patient (2.2%) developed grade 2 BPI, occurring 7 months after SBRT. Dose to the anatomic BP for the affected patient was 26.39 Gy. For the entire cohort, the median SCV and anatomic maximum BP doses were 8.44 and 7.14 Gy, respectively.

CONCLUSIONS

There is considerable variability in dose delivered to the BP after SBRT to apical lung tumors. BPI after single-fraction SBRT to apical tumors is rare and rates are comparable with those reported with multifraction regimens.

Correlation of Magnetic Resonance Imaging (Neurography) and Electrodiagnostic Study Findings with Intraoperative Findings in Post Traumatic Brachial Plexus Palsy

Background  The majority of brachial plexus injuries (BPIs) are caused by trauma; most commonly due to two-wheeler road accidents. It is important to determine whether the lesion in question is pre-ganglionic or post-ganglionic for purposes of surgical planning and prognosis. Diagnostic testing helps the surgeon to not only decide whether surgical intervention is required, but also in planning the procedure, thereby maximizing the patient's chances of early return to function. The aim of the study was to determine the diagnostic efficacy of electrodiagnostic studies (Edx) and magnetic resonance imaging (MRI) individually, and in unison, in detecting the type and site of BPI by comparison with intraoperative findings (which were used as the reference standard) in patients with posttraumatic BPI. Methods  It is an observational cross-sectional prospective randomized study, wherein 48 patients with BPI underwent a detailed clinical and neurological examination of the upper limb, Edx, MRI neurography and were subsequently operated upon. We assessed a total of 240 roots. The diagnosis of all spinal roots was noted on Edx. MRI was performed to look for root avulsion, pseudomeningocoele, and/or rupture injury. The patients were subsequently operated upon. All roots were traced from infraclavicular level right up to the foramen to ensure continuity of root or note rupture/ avulsion. The findings were tabulated. Results  MRI accurately diagnosed 138 of the 147 injured roots and MRI sensitivity for the detection of BPI was 93.88%, whereas Edx correctly identified 146 out of 147 injured roots and thus, had sensitivity of 99.32%; however, both lacked specificity (18.28 and 20.43%, respectively). With Edx and MRI in unison, sensitivity was 100% which meant that if a given patient with a BPI is subjected to both tests, not a single abnormal root will go unnoticed. Conclusion  Edx and MRI are two highly sensitive investigation modalities whose combined sensitivity is 100% for the detection of a root injury. Therefore, we recommend both tests as they are excellent screening tests.

True neurogenic thoracic outlet syndrome: late outcomes from a surgical series

BACKGROUND

True neurogenic thoracic outlet syndrome (TNTOS) is rare, and evaluation of surgical treatment is limited to a few studies in the literature. The purpose of this study is to present the results from a surgical series of 21 patients with TNTOS.

METHODS

Retrospective analysis on 21 patients diagnosed with TNTOS who underwent surgery. Demographic data and neurological status were characterized, and patients were classified in accordance with a pre-established scale for assessing the severity of hand impairment before and after surgery. Neuropathic pain was assessed using a visual analogue scale (VAS) and functional disability was quantified using the QuickDASH questionnaire. The results from before and after surgery were compared using the Wilcoxon test, and the significance level was taken to be 5%.

RESULTS

There was a significant difference in VAS values from before to after the operation (Wilcoxon test: p = 0.0001; r = 0.86). Most patients (90%) improved after surgery, and in 85% of these patients, the VAS improvement was greater than 50%. Improvement in hand function occurred in seven patients (33.3%), and in most of these cases (28.6%), this improvement was classified as mild. Most patients (93.3%) showed moderate to very severe functional disability at the end of the follow-up.

CONCLUSION

After surgery, only one-third of the cases showed improvement in motor function and most patients had significant functional disability. However, the improvement regarding pain was significant. Surgery to control this symptom should be recommended, even in cases of late presentation and severe motor impairment.

Location of brachial plexus birth injury affects functional outcomes in a rat model

Brachial plexus birth injury (BPBI) results in shoulder and elbow paralysis with shoulder internal rotation and elbow flexion contracture as frequent sequelae. The purpose of this study was to develop a technique for measuring functional movement and examine the effect of brachial plexus injury location (preganglionic and postganglionic) on functional movement outcomes in a rat model of BPBI, which we achieved through integration of gait analysis with musculoskeletal modeling and simulation. Eight weeks following unilateral brachial plexus injury, sagittal plane shoulder and elbow angles were extracted from gait recordings of young rats (n = 18), after which rats were sacrificed for bilateral muscle architecture measurements. Musculoskeletal models reflecting animal-specific muscle architecture parameters were used to simulate gait and extract muscle fiber lengths. The preganglionic neurectomy group spent significantly less (p = 0.00116) time in stance and walked with significantly less (p < 0.05) elbow flexion and shoulder protraction in the affected limb than postganglionic neurectomy or control groups. Linear regression revealed no significant linear relationship between passive shoulder external rotation and functional shoulder protraction range of motion. Despite significant restriction in longitudinal muscle growth, normalized functional fiber excursions did not differ significantly between groups. In fact, when superimposed on a normalized force-length curve, neurectomy-impaired muscle fibers (except subscapularis) accessed regions of the curve that overlapped with the control group. Our results suggest the presence of compensatory motor control strategies during locomotion following BPBI. The clinical implications of our findings support emphasis on functional movement analysis in treatment of BPBI, as functional and passive outcomes may differ substantially.

Localization of Brachial Plexopathies Using a Novel Diagnostic Program

Background: Assessing the extent and specific location of brachial plexus injuries can be difficult given the variety of mechanisms of injury and anatomic complexity of the plexus. We developed a program to accurately assess the location of a patient's neurologic injury based on electromyographic data. Purpose: We sought to test our hypothesis that the location of traumatic brachial plexopathies could be accurately assessed with a novel program that processed electromyogram (EMG) and mechanism of injury data. Methods: This retrospective diagnostic cohort study was carried out with a novel diagnostic algorithm developed with the Python programming language. The program accepts user input of muscles demonstrating decreased motor unit recruitment, positive sharp waves, or fibrillation potentials. The testing data set was derived from a registry of brachial plexus injuries treated at our center. The primary outcome was the percent concordance of the algorithm's diagnosis with the surgical diagnosis. Results: Ninety-five cases met the inclusion criteria. Median time from injury onset to EMG examination was 4 months; median time from EMG examination to surgery was 1.2 months. The program diagnosis matched the surgical diagnosis in 92 out of 95 (97%) of cases, including cases with multilevel injuries and additional peripheral nerve injuries. Conclusion: This program accurately localized brachial plexopathies in nearly all cases, including those involving polytrauma or complex patterns of injury. This algorithm may be valuable as an aid to complete electrodiagnostic examinations, a diagnostic adjunct when planning treatment of severe plexus palsies, or an educational tool.

Stereotactic body radiotherapy for apical lung tumors: Dosimetric analysis of the brachial plexus and preliminary clinical outcomes

BACKGROUND

Dosimetric constraints of the brachial plexus have not yet been well-established for patients undergoing stereotactic body radiotherapy (SBRT). This study evaluated long-term experience with the treatment of early stage apical lung tumors with SBRT and reports on dosimetric correlates of outcome.

METHODS

Between 2009 and 2018, a total of 78 consecutive patients with 81 apical lung tumors underwent SBRT for T1-3N0 non-small cell lung cancer. Apical tumors were those with tumor epicenter superior to the aortic arch. The brachial plexus (BP) was anatomically contoured according to the Radiation Therapy Oncology Group (RTOG) atlas. Patient medical records were retrospectively reviewed to determine incidence of brachial plexus injury (BPI) and a normal tissue complication probability model (NTCP) was applied to the dosimetric data.

RESULTS

Five patients (6.4%) reported neuropathic symptoms consistent with BPI and occurred a median 11.9 months after treatment (range, 5.2 to 28.1 months). Most common dose and fractionation in those developing BPI were 50 Gy in 5 fractions (4 patients). Symptoms consisted of pain in 2 patients (40.0%), numbness in the hand or axilla in 4 patients (80.0%), and ipsilateral hand weakness in 1 patient (20.0%). In the overall cohort the median BP Dmax (EQD2_{3 Gy}) was 5.13 Gy (range, 0.18 to 217.2 Gy) and in patients with BPI the median BP Dmax (EQD2_{3 Gy}) was 32.14 Gy (range, 13.4 to 99.9 Gy). The NTCP model gave good fit with an area under the curve (AUC) of 0.75 (OR 7.3, 95% CI: 0.8-68.3) for BP Dmax (EQD2_{3 Gy}) threshold of 20 Gy.

CONCLUSION

Significant variation exists in the dose delivered to the brachial plexus for patients treated by SBRT for apical lung tumors. The incidence of neuropathic symptoms in the post-SBRT setting was appreciable and prospective clinical correlation with dosimetric information should be utilized in order to develop evidence-based dose constraints.

Success with dorsal root entry zone lesioning after a failed trial of spinal cord stimulation in a patient with pain due to brachial plexus avulsion

Pain caused by brachial plexopathy (BP) represents a challenging clinical problem with few effective therapeutic options. Here, we present a patient with severe, painful BP after a high-impact motor vehicle accident who failed conservative treatments. A trial of cervical spinal cord stimulation was completed using multiple waveforms (tonic, BurstDR, and 10 kHz) over 14 days with only 30% to 40% pain reduction. Subsequently, he underwent dorsal root entry zone lesioning with a significant decrease in his pain 1 year later. Surgical exploration revealed extensive damage and avulsion of his cervical roots that was not observed on a previous brachial plexus magnetic resonance imaging. We discuss the etiology and diagnosis of traumatic BP, possible reasons for the failed spinal cord stimulation trial, and implications for management.

Approach to Limb Weakness

"Approach to limb weakness" provides an overview of the pathways of the motor system and the type of weakness seen with pathology at each level from the cortex to the muscle. This article provides the clinical pearls needed to identify different patterns of weakness and accurately localize the level of weakness. It offers important pointers that help distinguish among the different etiologies of weakness at each level, as well as various diagnostic approaches and treatments of diseases that lead to limb weakness. The diagnoses discussed are meant to be representative and not exhaustive, as a complete differential for each pattern of weakness is beyond the scope of this article.

Inpatient Diagnosis and Management of Neuromuscular Disorders

Although many neuromuscular conditions are evaluated on an outpatient basis owing to their chronic or progressive nature, more urgent evaluation and management is often required for the inpatient presenting with acute to subacute focal or generalized numbness or weakness. This review focuses on clinical pattern recognition and basic anatomic localization principles to aid in the identification of common, as well as some less frequently encountered, neuromuscular disorders in hospitalized patients. The characteristic clinical and diagnostic features, associated complications, and recommended treatments of key neuromuscular conditions with acute and subacute manifestations are discussed. These conditions can be life-threatening in some cases, such as in Guillain-Barré syndrome, owing to associated oropharyngeal weakness, respiratory failure, or marked dysautonomia. Prompt recognition of the clinical and pathologic features is therefore necessary to reduce associated morbidity and mortality.

Occult primary breast cancer presenting with brachial plexopathy: A case report

Breast cancer affects about one in eight women over the course of her lifetime. Occult breast cancer, in which primary breast cancer is detected without evidence of disease in the breast itself, comprises up to 1% of new diagnoses; this is typically detected from abnormal axillary lymph nodes, and distant metastases are rare. Here, we present an unusual case of occult breast cancer presenting as upper extremity pain, edema, and weakness, with a metastatic mass to the brachial plexus being the only site of disease.

Diagnosis of Neurogenic Thoracic Outlet Syndrome Based on the Clinical Status

OBJECTIVES

At our institute, we devised a clinical algorithm for diagnosis of neurogenic thoracic outlet syndrome (TOS). Our approach assisted in the accurate diagnosis and in detection of patients likely to benefit from surgical treatment. The purposes of this study were to propose our diagnostic approach to neurogenic TOS, and to describe the outcomes of surgical and conservative treatment.

METHODS

Patients (n = 91) who were suspected to have neurogenic TOS, and therefore, underwent a routine clinical protocol from January 2012 to January 2018 were reviewed. Through the clinical protocol, diagnosis of "true neurologic TOS", "symptomatic TOS", and "not likely TOS" was made. The visual analog scale (VAS) pain score and Disabilities of the Arm, Shoulder and Hand (DASH) score were used to assess the treatment outcomes. Satisfaction with surgery was assessed according to the Derkash classification as excellent, good, fair, or poor.

RESULTS

Among 91 patients with presumed neurogenic TOS, 25 patients were "true neurologic TOS", 61 patients were "symptomatic TOS", and five patients were "not likely TOS". Nineteen patients underwent supraclavicular decompression of the brachial plexus whose mean age at the time of surgery was 36.4 years. The VAS average pain score improved from 3.6 to 0.8, and the DASH score improved from 38.4 to 17.1. According to the Derkash classification, ten patients (53%) rated their recovery as excellent, four (21%) as good, and five (26%) as fair. Sixty-seven patients underwent conservative treatment. At the last follow-up visit, their VAS and DASH score were 2.3 and 11.8, respectively.

CONCLUSIONS

By using an algorithm, we diagnosed the patients suspected to have neurogenic TOS into three groups based on clinical status. We surgically treated 19 patients using supraclavicular approach, and achieved favorable outcomes.

The relationship between alexithymia, sensory phenotype and neurophysiological parameters in patients with chronic upper limb neuropathy

In this study, we investigated the relationship between sensory abnormalities evaluated by quantitative sensory testing (QST) and alexithymia, depression and anxiety in patients with neuropathic pain involving the upper limbs. We enrolled 62 patients (34 with carpal tunnel syndrome, 7 with brachial plexopathy, 3 with cervical painful radiculopathy, 5 with ulnar entrapment neuropathy at elbow and 13 with post-burn hypertrophic scars) and 48 healthy controls. All underwent nerve conduction studies (NCS), evaluation of cold, heat pain and vibration detection threshold (VDT) by QST and evaluation of alexithymia by Toronto Alexithymia Scale (TAS-20), depression by Beck Depression Inventory II (BDI-II), anxiety by State-Trait Anxiety Inventory (STAI-Y), level of psychological distress by 12-item General Health Questionnaire (GHQ-12) and perceived social support by the Multidimensional Scale of Perceived Social Support (MSPSS). The general linear model analysis revealed a significant relationship between TAS-20 overall and TAS-20 sub-score for difficulty identifying feelings and VDT z-scores in the left index with no interaction by year of education and sensory NCS results. Our results demonstrated the association between impairment of vibratory sensation of the left hand, reflecting cutaneous mechanoceptor dysfunction, and alexithymia, particularly the difficulty to identify feelings. The importance of delivering to patients with neuropathic pain personalized care that takes into account not only the neurophysiological aspects but also the aspects of mental functioning is discussed.

[Lower trunk brachial plexopathy due to hematoma following median sternotomy: a case report]

We present the case of an 81-year-old woman who underwent aortic valve replacement and coronary artery bypass surgery by median sternotomy. Following the operation, she experienced distal muscle weakness in her left upper limb and numbness in the medial part of her left forearm and palm. Nerve conduction study revealed low amplitudes of her left ulnar compound muscle action potential (CMAP) and sensory nerve action potential (SNAP), radial CMAP, and medial antebrachial cutaneous SNAP. Needle electromyography showed denervation potentials in the extensor digitorum communis and abductor pollicis brevis. CT and MRI showed a left first rib fracture and a hematoma nearby. Short-T1 inversion recovery image (STIR) showed a high-intensity area in the left root of C8. Based on these findings, we diagnosed the patient with lower trunk brachial plexopathy due to hematoma.

Brachial and lumbosacral plexopathies: A review

Diseases of the brachial and lumbosacral plexus are uncommon and complex. The diagnosis of plexopathies is often challenging for the clinician, both in terms of localizing a patient's symptoms to the plexus as well as determining the etiology. The non-specific clinical features and similar presentations to other root, nerve, and non-neurologic disorders emphasize the importance of a high clinical index of suspicion for a plexopathy and comprehensive clinical evaluation. Various diagnostic tests, including electrodiagnostic (EDX) studies, neuroimaging (including ultrasound, MRI, or PET), serologic studies, and genetic testing, may be used to confirm a plexopathy and assist in identifying the underlying etiology. EDX testing plays an important role in confirming a plexopathy defining the localization, pathophysiology, chronicity, severity, and prognosis. Given the complexity of the plexus anatomy, multiple common and uncommon NCS and an extensive needle examination is often required, and a comprehensive, individualized approach to each patient is necessary. Treatment of plexopathies often focuses on symptomatic management although, depending on the etiology, specific targeted treatments may improve outcome. This article reviews the clinical features, EDX approaches, and evaluation and treatment of brachial and lumbosacral plexopathies.

Backpack palsy and other brachial plexus neuropathies in the military population

Brachial plexus neuropathy is often seen in the military population, especially due to pressure (backpack palsy, BPP) or idiopathic (neuralgic amyotrophy, NA). We aimed to gain insight in the disease characteristics of soldiers with brachial plexus neuropathies in the Dutch military population and to compare disease characteristics between patients with BPP and NA. In this retrospective chart review study we aimed to include all patients with brachial plexus neuropathy, who presented in the Joint Military Hospital between 1 January, 2011 and 31 December, 2016. We calculated the incidence of NA and BPP and Chi-square tests or Student t tests were performed for differences in patient characteristics between NA and BPP. We included 127 patients, 63 with BPP, 45 with NA, 10 with traumatic brachial plexus neuropathy, and 9 with other plexopathy. The incidence of brachial plexus neuropathy was 50/100 000 person years overall, 25/100 000 person years for BPP, and 18/100 000 person years for NA. Patients in the BPP group differed from the NA with regard to pain (BPP 41% vs NA 93%, P = .000), atrophy (13% BPP vs 29% NA, P = .049), and sensory symptoms (83% BPP vs 44% NA, P = .000). In the BPP group 90% had incomplete recovery and in the NA group 78%. Our study showed a high incidence of BPP and NA in the military population and suggests recovery is not so benevolent as previously thought. Future research is necessary to improve insight and outcome of military patients with brachial plexus neuropathies.

Ultrasound imaging of nerves in the neck: Correlation with MRI, EMG, and clinical findings

Objective

We evaluated the performance of ultrasound in the detection of neuropathy of the suprascapular nerve (SSN), long thoracic nerve (LTN), spinal accessory nerve (SAN), and phrenic nerve and compared this performance with MRI.

Methods

A retrospective review of 56 patients who had undergone ultrasound imaging of the SSN, LTN, SAN, and phrenic nerve was performed. Diagnoses made by ultrasound, MRI, EMG reports, and clinical and operative notes were recorded.

Results

Ultrasound was successful in visualizing nerves in the neck in the overwhelming majority of cases. Sonographic findings were typically in agreement with MRI and clinical findings.

Conclusion

Ultrasound is effective in the visualization and diagnostic evaluation of the SSN, LTN, SAN, and phrenic nerve.

Classification of evidence

This study provides Class IV evidence that ultrasound can effectively visualize and diagnose neuropathy of the SSN, LTN, SAN, and phrenic nerve in the neck.

Radiation-induced brachial plexus toxicity after SBRT of apically located lung lesions

Purpose: To evaluate the rate and dose response of brachial plexus toxicity post stereotactic body radiation therapy (SBRT) of apically situated lung lesions. Material/methods: We retrospectively identified all patients with apically located tumors, defined by the epicenter of the tumor being located superiorly to the aortic arch, and treated with SBRT between 2008 and 2013. Patients with a shorter follow-up than 6 months were excluded. Primary aim was to evaluate radiation-induced brachial plexopathy (RIBP). Dose to the plexus was assessed by a retrospective delineation of the brachial plexus on the CT used for treatment planning. Then, D_max, D_0.1cc, D_1cc and D_3.0cc of the brachial plexus were collected from the dose-volume histograms (DVH) and recalculated to the biologically effective dose (BED) using α/β = 3 Gy. A normal tissue complication probability (NTCP) model, based on four different dose-volume parameters (BED_3,max, BED_3,0.1cc, BED_3,1.0cc, BED_3,3.0cc) was fitted to the data. Results: Fifty-two patients with 56 apically located tumors were identified. Median prescription dose per fraction was 15 Gy (range 6-17) and median number of fractions was 3 (3-10). With a median follow-up of 30 months (6.1-72) seven patients experienced maximum grade 2 (scored 3 times) or 3 (scored 4 times) RIBP after a median of 8.7 months (range 4.0-31). Three patients had combined symptoms with pain, sensory and motor affection and four patients had isolated pain. Median BED_3,max for the patients experiencing RIBP was 381 Gy (range 30-524) versus BED_3,max of 34 Gy (range 0.10-483) for the patients without RIBP. The NTCP models showed a very high predictive ability (area under the receiver operating characteristic curve (AUC) 0.80-0.88). Conclusion: SBRT of apically located lung lesions may cause severe neurological symptoms; for a three-fraction treatment, we suggest that the maximum dose to the plexus should be kept ≤30 Gy (130 Gy BED₃).

A prospective study of high resolution ultrasound in brachial plexopathies - Correlation with electrophysiological measurements

OBJECTIVES

To evaluate the diagnostic role of ultrasound in brachial plexopathies.

METHODS

We included 59 healthy subjects (HS) and 42 patients consecutively referred with clinical suspicion of brachial plexopathy from October 2015 to May 2016. Patients underwent routine electrodiagnostic testing (EDx) as reference standard and a blinded standardised ultrasound examination of the brachial plexus as index test with cross-sectional area (CSA) as the ultrasound parameter of choice.

RESULTS

Seventeen patients were diagnosed by EDx with brachial plexopathy, ten with mononeuropathies, and ten had normal EDx. Five had a cervical radiculopathy. In 11 (64%) out of the 17 patients with EDx diagnosed plexopathy, we found at least one abnormal level on ultrasound. Six (60%) out of ten normal EDx patients had a normal ultrasound examination at all levels. Ultrasound identified the same abnormal level(s) as EDx in eight (73%) of the 11 patients who had both abnormal EDx and ultrasound results. Mean CSA was higher in the plexopathy group compared to HS at the level of the C6 root (p = .022), the middle trunk (p = .027), and the medial cord (p = .003).

CONCLUSION

Ultrasound examination showed abnormalities in patients with brachial plexopathies in good agreement with EDx.

SIGNIFICANCE

Ultrasound may be an important supplement to electrodiagnostics in evaluating brachial plexopathies.

Brachial plexus impingement secondary to implantable cardioverter defibrillator: A case report

Overall complication rates of 9.1% have been reported following implantable cardioverter defibrillator (ICD) placement. Brachial plexus injury is infrequently reported in the literature. We describe a 26-year-old female experiencing left arm nerve pain, a positive Tinel's sign, numbness in the median nerve distribution of the hand and biceps muscle weakness following revision ICD via subclavian vein approach. Nerve conduction studies identified severe partial left brachial plexopathy, which remained incompletely resolved with conservative management. Surgical exploration revealed lateral cord impingement by the ICD generator and a loop of the ICD lead, along with fibrosis, necessitating surgical neurolysis and ICD generator repositioning. As increasing numbers of patients undergo cardiac device implantation, it is incumbent on practitioners to be aware of potential increases in the prevalence of this complication.

A Comprehensive Protocol to Prevent Brachial Plexus Injury During Ankylosing Spondylitis Surgery

PURPOSE

This article describes a comprehensive protocol to protect the brachial plexus when performing pedicle subtraction osteotomy for ankylosing spondylitis patients with thoracolumbar kyphosis.

DESIGN

A descriptive study was conducted.

METHODS

Records of 101 cases from October 2013 to December 2016 were retrospectively audited. The protocol included five items: (1) preoperative assessment of motion range and nerve function of limbs and trunks; (2) preoperative positioning according to the assessment results; (3) intra-operative somatosensory evoked potential and blood pressure monitoring; (4) intra-operative repositioning according to the monitoring alarm signals; and (5) postoperative neurological function check.

FINDINGS

Five patients showed impending brachial plexus injury indicators, including two who had a decrease in blood pressure and three who had a decrease in the amplitude of somatosensory evoked potential. After adjustment of position and soft pads, one patient had brachial plexus injury (0.99%) and the recovery time was 2 weeks.

CONCLUSIONS

With this comprehensive strategy, the brachial plexus could be effectively protected during the surgery.

Organs at risk in lung SBRT

Lung stereotactic body radiotherapy (SBRT) is an accurate and precise technique to treat lung tumors with high 'ablative' doses. Given the encouraging data in terms of local control and toxicity profile, SBRT has currently become a treatment option for both early stage lung cancer and lung oligometastatic disease in patients who are medically inoperable or refuse surgical resection. Dose-adapted fractionation schedules and ongoing prospective trials should provide further evidence of SBRT safety trying to reduce toxicities and complications. In this heterogeneous scenario, a non-systematic review of dose constraints for lung SBRT was performed, including the main organs at risk in the thorax.

Contralateral Involvement of Congenital Muscular Torticollis and Clavicular Fracture

Congenital muscular torticollis (CMT) is known to concur with some conditions such as developmental dysplasia of the hip or brachial plexus injury, which gives us some insights for pathogenesis of CMT. Although clavicular fracture is the most common fracture in newborns, little is known about concurrence of CMT and clavicular fracture. Our clinical experience led us to realize that concurrence of CMT and clavicular fracture tended to occur on the contralateral side for each other rather than the ipsilateral side. This study aimed to verify contralateral concurrence of CMT and clavicular fracture. This is a retrospective cohort study in a tertiary hospital, including 996 subjects with CMT. Concurrent clavicular fracture was found in 20 of 996 subjects with CMT, with the concurrence rate being 2.01%. Concurrent clavicular fracture and clavicular fracture occurred on the contralateral side for each other in 18 subjects (90%) rather than the ipsilateral side. This contralateral concurrence between side of CMT and clavicular fracture was significant (P = 0.001), with an odds ratio of 81 (P = 0.0032). Concurrent clavicular fracture and clavicular fracture seem to occur significantly more on the contralateral side for each other. Underlying mechanism for consistent contralateral concurrence needs to be verified in the near future.

Electrodiagnostic studies in the intensive care unit: A comparison study 2 decades later

INTRODUCTION

Since the late 1980s, critical illness myopathy (CIM) and critical illness polyneuropathy (CIP) have been increasingly recognized in the intensive care unit (ICU). We explored whether these causes of ICU weakness were now more likely to lead to electrodiagnostic studies (EDX) at our institution than they were 19-20 years earlier.

METHODS

We reviewed 100 consecutive ICU patients who underwent EDX from 2009 to 2015 and compared them to a previously reported study population from 1990-1995.

RESULTS

Thirty-seven (39%) had CIM, CIP, or both versus 55% in the previous study (P = 0.04). Thirty-four (36%) were diagnosed with "traditional" pre-ICU causes of weakness, such as motor neuron disease or Guillain-Barre syndrome, versus 29% in the earlier study (P = 0.3).

DISCUSSION

CIM and CIP continue to be common disorders that lead to ICU EDX, but their proportion declined compared with 19-20 years earlier, possibly due to the perceived role and selective use of EDX in the ICU. Muscle Nerve 57: 772-776, 2018.

Backpack palsy with Horner's syndrome

Traumatic injuries to the brachial plexus are typically high impact and can be debilitating, life-changing injuries. Backpack palsy is a rare but well-established cause of brachial plexus injury, arising as a result of heavy backpack use. We present an unusual case of backpack palsy with Horner's syndrome.

The thoracic outlet syndromes: Part 2. The arterial, venous, neurovascular, and disputed thoracic outlet syndromes

The thoracic outlet syndromes (TOSs) are a group of etiologically and clinically distinct disorders with 1 feature in common: compression of 1 or more neurovascular elements as they traverse the thoracic outlet. The medical literature reflects 5 TOSs: arterial; venous; traumatic neurovascular; true neurogenic; and disputed. Of these, the first 4 demonstrate all of the features expected of a syndrome, whereas disputed TOS does not, causing many experts to doubt its existence altogether. Thus, some categorize disputed TOSs as cervicoscapular pain syndrome rather than as a type of TOS. To better understand these disorders, their distinctions, and the reasoning underlying the categorical change of disputed TOS from a form of TOS to a cervicoscapular pain syndrome, a thorough understanding of the pertinent anatomy, pathology, pathophysiology, and electrodiagnostic manifestations of these pathophysiologies is required. This review of the TOSs is provided in 2 parts. In part 1 we covered general information pertinent to all 5 TOSs and reviewed true neurogenic TOS in detail. In part 2, we review the arterial, venous, traumatic neurovascular, and disputed forms of TOS. Muscle Nerve 56: 663-673, 2017.

The thoracic outlet syndromes: Part 1. Overview of the thoracic outlet syndromes and review of true neurogenic thoracic outlet syndrome

The thoracic outlet syndromes (TOSs) are a group of etiologically and clinically distinct disorders with 1 feature in common: compression of 1 or more neurovascular elements as they traverse the thoracic outlet. The medical literature reflects 5 TOSs: arterial; venous; traumatic neurovascular; true neurogenic; and disputed. Of these, the first 4 demonstrate all of the features expected of a syndrome, whereas disputed TOS does not, causing many experts to doubt its existence altogether. Thus, some categorize disputed TOS as a cervicoscapular pain syndrome rather than as a type of TOS. To better understand these disorders, their distinctions, and the reasoning underlying the categorical change of disputed TOS from a form of TOS to a cervicoscapular pain syndrome, a thorough understanding of the pertinent anatomy, pathology, pathophysiology, and the electrodiagnostic manifestations of their pathophysiologies is required. This review of the TOSs is provided in 2 parts. In this first part we address information pertinent to all 5 TOSs and reviews true neurogenic TOS. In part 2 we review the other 4 TOSs. Muscle Nerve 55: 782-793, 2017.

Thoracic outlet syndromes. The so-called "neurogenic types"

Neurogenic thoracic outlet syndrome (TOS) is one of the most controversial pain syndromes of the upper limbs. The controversies revolve around both the diagnosis and treatment of the non-specific or subjective subtypes. Their diagnosis rests on a combination of history, suggestive symptoms and clinical examination. Proximal pain is primarily muscular in origin, while distal symptoms may be the result of intermittent nerve compression and/or myofascial pain syndrome. Stringent clinical criteria are required to confirm the diagnosis of subjective TOS. In reality, multiple factors can be entangled, with TOS being one element within a multifactorial pain disorder; any musculotendinous pathology of the upper limb and any peripheral nerve entrapment require screening for potential concomitant TOS. Surgery is indicated in most cases of true neurogenic TOS, whereas rehabilitation is the standard treatment for subjective TOS.