Neuroanatomy of the brachial plexus: The missing link in the continuity between the central and peripheral nervous systems

Lateral Antebrachial Cutaneous Neuropathy: A Review of 15 Cases

Background: Lateral antebrachial cutaneous nerve is a terminal sensory branch of the musculocutaneous nerve. Lateral antebrachial cutaneous neuropathy (LABCN) is rare and often underdiagnosed. Less than 100 cases have been described in the orthopedic literature.

Methods: It’s a single-center retrospective study. A retrospective chart review of patients with LABCN who were seen over 16 years was performed. Demographics and detailed clinical information were recorded. In addition, electrodiagnostic data were reviewed, and clinical outcome was recorded.

Results: Fifteen patients were included in this study. Postsurgical etiology was the most common (n = 7) cause of LABCN. Other cases included antecubital fossa phlebotomy and intravenous placement (n = 4), trauma (n = 1), overuse or repetitive forearm use (n = 2), and dog bite (n = 1). No etiology was found in one case, but the patient had diabetes.

Conclusion: Our study proposes that patient positioning during orthopedic surgeries leading to stretch or compression of the lateral antebrachial cutaneous nerve is the most likely cause of LABCN. Antecubital fossa needle placement is the second most common cause of LABCN. However, it’s a rare mononeuropathy and can be underdiagnosed. Therefore, detailed history, examination, and nerve conduction studies of the bilateral lateral antebrachial cutaneous nerve could help establish the diagnosis after other etiologies have been carefully excluded.

Epidemiology, etiology, and types of severe adult brachial plexus injuries requiring surgical repair: systematic review and meta-analysis

The literature describing epidemiology, etiology, and types of serious brachial plexus injuries (BPIs) is sparse. The aim of this review was to investigate the epidemiological and etiopathogenetical data of serious BPIs undergoing surgical reconstruction. A systematic search was conducted from January 1985 to December 2017. All studies that reported data about prevalence of specific types and causes of BPIs in adults treated surgically were included and cumulatively analyzed. Ten studies including 3032 patients were identified. The pooled prevalence of closed BPIs was 93% (95% CI: 87-97%), lacerations accounted for 3% (95% CI: 1-6%), and gunshot wounds (GSWs) for 3% (95% CI: 0-7%). The prevalence of male patients was 93% (95% CI: 90-96%) and female cases 7% (95% CI: 4-10%). The most common cause of closed BPI was motorcycle accidents with 67% (95% CI: 49-82%) prevalence followed by car crashes with 14% (95% CI: 8-20%). Other causes were rare. Ninety percent (95% CI: 78-98%) of patients suffered from a supraclavicular or combined supra-/infraclavicular trauma, while 10% (95% CI: 2-22%) from isolated infraclavicular injury. The prevalence of complete lesions was 53% (95% CI: 47-58%) followed by upper plexus lesion with 39% (95% CI: 31-48%) and lower plexus injury with 6% (95% CI: 1-12%). This meta-analysis demonstrates that the typical patient suffering from severe BPI is a male after motorcycle accident with closed supraclavicular injury causing complete or slightly less commonly upper plexus palsy. Lacerations and GSWs of brachial plexus are rare.

Recombinant peptide derived from the venom the Phoneutria nigriventer spider relieves nociception by nerve deafferentation

The avulsion of nerve roots of the brachial plexus that is commonly seen in motorcycle accidents is a type of neuropathy due to deafferentation. This type of pain is clinically challenging since therapeutical protocols fail or have severe side effects. Thus, it is proposed to evaluate the antinociceptive activity of the recombinant CTK 01512-2 peptide that is derived from the venom of the Phoneutria nigriventer spider, as a future new therapeutical option. The neuropathic pain was surgically induced by avulsion of the upper brachial plexus trunk in groups of male Wistar rats and after 17 days, they were treated intrathecally with morphine, ziconotide, and CTK 01512-2. Behavioral tests were performed to evaluate mechanical and thermal hyperalgesia, cold allodynia, the functional activity of the front paw, and exploratory locomotion after the treatments. The peripheral blood samples were collected 6 h after the treatments and a comet assay was performed. The spinal cord was removed for the lipoperoxidation dosing of the membranes. The cerebrospinal fluid was analyzed for the dosage of glutamate. The recombinant peptide showed an antinociceptive effect when compared to the other drugs, without affecting the locomotor activity of the animals. Mechanical and thermal hyperalgesia, as well as cold allodynia, were reduced in the first hours of treatment. The levels of glutamate and the damage by membrane lipoperoxidation were shown to be improved, and genotoxicity was not demonstrated. In a scenario of therapeutical failures in the treatment of this type of pain, CTK 01512-2 was shown as a new effective alternative protocol. However, further testing is required to determine pharmacokinetics.

Non-neoplastic pathology at the crossroads between neck imaging and cardiothoracic imaging

The thoracic inlet is located at the crossroads between imaging of the neck and chest. It represents an important anatomic landmark, serving as the central conducting pathway for many vital structures extending from the neck into the chest and vice versa. Many important body systems are located within this region, including the enteric, respiratory, vascular, lymphatic, neurologic, and endocrine systems. A detailed examination of this region is essential when reviewing neck and thoracic imaging. This article will discuss the normal anatomic boundaries of the thoracic inlet and present an image-rich systematic discussion of the non-neoplastic pathology that can occur in this region. The neoplastic pathology of the thoracic inlet will be covered in a companion article.

The distribution of brachial plexus lesions after experimental traction: a cadaveric study

OBJECTIVEThe objective of the present study was to determine experimentally the distribution of lesions caused in the cadaveric brachial plexus (BP) by excessive stretching. The authors attempted to delineate the correlation between the direction of stretching and sites of lesions.METHODSFifteen specimens (each comprised the spinal segment C4-T2 with 2 BPs) were harvested from adult cadavers. Each BP was stretched in a mechanical testing machine at a constant speed of 200 mm/min. Specimens were divided into 3 groups: in group A the BPs were stretched caudally at a 45° angle to the spinal midline; in group B they were stretched perpendicularly to the spinal midline; and in group C the stretching was caudally parallel to the midline. Lesions of each BP were identified and analyzed. A graph of load against dislocation was registered when stretching to delineate the maximal force (Fmax), defined as the maximum load at which BP failure occurs.RESULTSBased on macroscopic examination, 140 sites of mechanical damage were identified in 30 BPs. Preganglionic injuries (63.6% of lesions), defined as avulsions of the spinal ganglia with their rootlets, were found in 89 spinal nerves. In group B-in which specimens were stretched perpendicularly to the spinal segment-preganglionic injuries were significantly more frequent (41 avulsed spinal nerves) than in groups A and C (21 and 27 avulsed spinal nerves, respectively). Postganglionic lesions equivalent to neurotmesis were found in 51 sites (36.4% of all lesions) along spinal nerves, trunks, divisions, and cords. Postganglionic lesions in group B were much less frequent (8) as compared with groups A and C (24 and 19, respectively).CONCLUSIONSPredominance of preganglionic lesions suggests that attachments of the BP to the spine are more susceptible to traction than postganglionic elements. Preganglionic lesions were mainly produced in C7, C8, and T1 spinal nerves, suggesting their weaker attachment to the spine than in the case of C5 and C6 nerves. Preganglionic lesions were highly correlated with a traction perpendicular to the spine, whereas postganglionic lesions were provoked mainly by traction directed at 45° caudally or by means of caudal traction parallel to the midline. This discrepancy implies a relationship between mechanical resistance of pre- and postganglionic elements of the BP and the vector of force.

Protective myoelectric activity at performing upper limb neurodynamic test 1 in breast cancer survivors. A cross-sectional observational study

Myoelectric activity and range of motion during ULNT1 were recorded in 62 breast cancer (BC) survivors who had axillary lymph node dissection (n = 30) or sentinel lymph node biopsy (n = 32) within the previous 18 months, and 63 age-matched healthy women. BC survivors' symptoms were reproduced by ULNT1 and exhibited greater myoelectric activity in the biceps brachii than healthy women (MD (95% CI): 21,26 (10,83-31,70)). No differences between the axillary lymph node dissection and sentinel lymph node biopsy groups (MD (95% CI): 8,47 (-7,84-24,79)) were found. Myoelectric activity in the triceps brachii was greater in the sentinel lymph node biopsy group (MD (95% CI): 2,70 (-2,06-7,60)). BC survivors exhibited less shoulder and elbow range of motion during ULNT1 than healthy women. Increased upper limb nerve mechanosensitivity in BC survivors was associated with a greater protective muscle response during ULNT1.

Diagnosis of brachial and lumbosacral plexus lesions

To most doctors, brachial and lumbosacral plexopathies are known as difficult disorders, because of their complicated anatomy and relatively rare occurrence. Both the brachial, lumbar, and sacral plexuses are extensive PNS structures stretching from the neck to axillary region and running in the paraspinal lumbar and pelvic region, containing 100000-200000 axons with 12-15 major terminal branches supplying almost 50 muscles in each limb. The most difficult part in diagnosing a plexopathy is probably that it requires an adequate amount of clinical suspicion combined with a thorough anatomical knowledge of the PNS and a meticulous clinical examination. Once a set of symptoms is recognized as a plexopathy the patients' history and course of the disorder will often greatly limit the differential diagnosis. The most common cause of brachial plexopathy is probably neuralgic amyotrophy and the most common cause of lumbosacral plexopathy is diabetic amyotrophy. Traumatic and malignant lesions are fortunately rarer but just as devastating. This chapter provides an overview of both common and rarer brachial and lumbosacral plexus disorders, focusing on clinical examination, the use of additional investigative techniques, prognosis, and treatment.

Lateral antebrachial cutaneous neuropathy following the long head of the biceps rupture

Lateral antebrachial cutaneous neuropathies present as purely sensory lesions, manifesting as elbow pain or dysesthetic pain over the lateral forearm. Classically, entrapment of the lateral antebrachial cutaneous nerve has been documented at the lateral edge of the biceps tendon as it exits the deep fascia in the antecubital fossa. We report a case of lateral antebrachial cutaneous nerve traction neuritis, rather than entrapment, resulting from a rupture of the long head of the biceps. The biceps displaced the nerve laterally, resulting in sensory loss and severe allodynia. The patient's symptoms were relieved with proximal biceps tenodesis.

Functional cooperation of of IL-1β and RGS4 in the brachial plexus avulsion mediated brain reorganization

BACKGROUNDS

There is considerable evidence that central nervous system is continuously modulated by activity, behavior and skill acquisition. This study is to examine the reorganization in cortical and subcortical regions in response to brachial plexus avulsion.

METHODS

Adult C57BL/6 mice were divided into four groups: control, 1, 3 and 6 month of brachial plexus avulsion. IL-1β, IL-6 and RGS4 expression in cortex, brainstem and spinal cord were detected by BiostarM-140 s microarray and real-time PCR. RGS4 subcellular distribution and modulation were further analyzed by primary neuron culture and Western Blot.

RESULTS

After 1, 3 and 6 months of brachial plexus avulsion, 49 (0 up, 49 down), 29 (17 up, 12 down), 13 (9 up, 4 down) genes in cerebral cortex, 40 (8 up, 32 down), 11 (7 up, 4 down), 137 (63 up, 74 down) in brainstem, 27 (14 up, 13 down), 33 (18 up, 15 down), 60 (29 up, 31 down) in spinal cord were identified. Among the regulated gene, IL-1β and IL-6 were sustainable enhanced in brain stem, while PKACβ and RGS4 were up-regulated throughout cerebral cortex, brainstem and spinal cord in 3 and 6 month of nerve injury. Intriguingly, subcellular distribution of RGS4 in above three regions was dependent on the functional correlation of PKA and IL-1β.

CONCLUSION

Data herein indicated that brachial plexus avulsion could efficiently initiate and perpetuate the brain reorganization. Network involved IL-1β and RGS4 signaling might implicate in the re-establish and strengthening of the local circuits at the cortical and subcortical levels.

MR imaging of the thoracic inlet

The thoracic inlet serves as the junction between the neck and the chest. As such, it is sometimes considered a sort of "no-man's-land" between the well-defined and comfortable territories of the thoracic radiologist and that of the head and neck radiologist. Crucial digestive, respiratory, vascular, lymphatic, and neural structures traverse the thoracic inlet. Endocrine structures also are in close proximity to, and sometimes extend into, the thoracic inlet. Familiarity with the normal anatomy of the thoracic inlet on routine chest or neck imaging, and on dedicated high-resolution examinations of such areas as the brachial plexus, is critical for detection and characterization of pathologic conditions.

Novel double-superior-trunk injury of the brachial plexus: a case report

Brachial plexus injuries are generally rare and a double-superior-trunk injury of the brachial plexus has never been reported before. We report the first case of a brachial plexus injury in a 43-year-old Chinese male with a double superior trunk. This was observed incidentally during an operation 1 month after initial traction injury sustained in a car accident. The double superior trunk of the brachial plexus was formed by the double roots of C5 and C6, respectively. Six months after discharge, the patient reported the recovery of most of the function of his left arm except the muscles innervated by the radial nerve. Two years after discharge, he reported almost full functional recovery of his left arm. We discuss what is known about anatomical variations of the brachial plexus, and the possible association between this novel brachial plexus anatomy and the almost complete functional recovery of the arm.