Nerve Entrapment Syndromes of the Elbow, Forearm, and Wrist

Ergonomic considerations for the modern radiology practice: An update

The average post-pandemic modern radiology practice is experiencing an ever-increasing workload volume with overall relatively similar staffing levels, regardless of practice setting. This has resulted in an increased workload demand for the average diagnostic radiologist, which in many cases translates to longer working hours. It is now more important than ever to be cognizant of various work-related injuries, including repetitive-stress injuries and vision-related ailments as examples, in relation to the working conditions of the radiologist. This article will discuss commonly occurring conditions and ergonomic considerations that the radiologist can employ to reduce the risk of work-related injuries.

Comparing the efficacy of multiple quantitative and qualitative ultrasound parameters for the diagnosis of carpal tunnel syndrome

PURPOSE

Carpal tunnel syndrome (CTS) is a compression neuropathy causing significant morbidity. Over the years, ultrasound has been evaluated as an alternative to nerve conduction study (NCS) for diagnosing CTS, however, there is no consensus as to which ultrasound parameter is the best. Our study aimed to determine and compare the efficacy of various ultrasound-based variables for diagnosis of CTS.

METHODS

80 patients with clinical suspicion of CTS underwent ultrasound examination with calculation of cross-sectional area (CSA), delta CSA, wrist forearm ratio (WFR), palmer bowing (PB), flattening ratio (FR), flexor retinaculum thickness (FT), and evaluation of echogenicity and vascularity of median nerve. NCS was taken as the gold standard and the diagnostic efficacy of all these variables was compared, followed by receiver operator curve (ROC) analysis.

RESULTS

Delta CSA had the highest accuracy (91.25%), followed by CSAc (80%), WFR (78.75%), and PB (73.75%). Youden's index and sensitivity were highest for delta CSA (0.783 and 96.15% respectively), while specificity was highest for FT (89.29%). The highest area under the curve was noted for delta CSA (97.1%), followed by WFR (AUC = 87.4%) and CSAc (AUC = 86.0%).

CONCLUSION

Delta CSA was found to be the best ultrasound parameter for diagnosis of CTS, followed by CSAc, WFR, and PB, and can be used as an alternative to NCS. Using ROC analysis this study also predicted the best cut-off values for these parameters which could improve their diagnostic accuracy and further research is needed to confirm these findings.

Ultrasonographic differential diagnosis of medial elbow pain

Medial elbow pain is a common musculoskeletal problem among individuals engaging in repetitive activities. Medial epicondylitis is the predominant cause of this pain. However, other potential causes must be considered as part of the differential diagnosis. This article discusses several etiologies of medial elbow pain, including medial epicondylitis, ulnar neuropathy, snapping triceps syndrome, ulnar collateral ligament injury, medial antebrachial cutaneous neuropathy, and diseases of the elbow joint, with an emphasis on ultrasound (US) findings. Awareness of possible diagnoses and their US features can assist radiologists in establishing a comprehensive diagnosis for medial elbow pain.

Median Nerve Entrapment by Superficial Brachioulnar Artery: Anatomical Insights and Clinical Perspective

Entrapment neuropathy of the median nerve is typically caused by compression at specific anatomical points. However, idiopathic cases, where the standard anatomical compression points are normal, pose diagnostic challenges. This report highlights a unique case discovered during an anatomical dissection of the right upper limb in a 62-year-old male cadaver, where the median nerve was compressed by an unusual branch of the brachial artery, termed the superficial brachioulnar artery (SBUA). The median nerve formed at the distal half of the arm, receiving additional components from the lateral cord, with a noted communication with the musculocutaneous nerve. The SBUA, originating from the brachial artery, passed between the roots of the median nerve and continued superficially, forming the superficial palmar arch. The coexistence of neurovascular variations is clinically significant as it may lead to nerve compression and subsequent symptoms. This case is the first documented instance of median nerve compression by an SBUA. Such variations are crucial for surgical and diagnostic procedures, as abnormal vascular structures can be mistaken for veins, leading to iatrogenic injuries. In addition, understanding these variations helps explain idiopathic median nerve neuropathies and highlights the need for thorough anatomical knowledge to prevent complications during surgical interventions.

Hourglass-like constrictions on MRI are common in electromyography-confirmed cases of neuralgic amyotrophy (Parsonage-Turner syndrome): A tertiary referral center experience

INTRODUCTION/AIMS

Hourglass-like constrictions (HGCs) of involved nerves in neuralgic amyotrophy (NA) (Parsonage-Turner syndrome) have been increasingly recognized with magnetic resonance neurography (MRN). This study sought to determine the sensitivity of HGCs, detected by MRN, among electromyography (EMG)-confirmed NA cases.

METHODS

This study retrospectively reviewed records of patients with the clinical diagnosis of NA, and with EMG confirmation, who underwent 3-Tesla MRN within 90 days of EMG at a single tertiary referral center between 2011 and 2021. "Severe NA" positive cases were defined by a clinical diagnosis and specific EMG criteria: fibrillation potentials or positive sharp waves, along with motor unit recruitment (MUR) grades of "discrete" or "none." On MRN, one or more HGCs, defined as focally decreased nerve caliber or diffusely beaded appearance, was considered "imaging-positive." Post hoc inter-rater reliability for HGCs was measured by comparing the original MRN report against subsequent blinded interpretation by a second radiologist.

RESULTS

A total of 123 NA patients with 3-Tesla MRN performed within 90 days of EMG were identified. HGCs were observed in 90.2% of all NA patients. In "severe NA" cases, based on the above EMG criteria, HGC detection resulted in a sensitivity of 91.9%. Nerve-by-nerve analysis (183 nerve-muscle pairs, nerves assessed by MRN, muscles assessed by EMG) showed a sensitivity of 91.0%. The second radiologist largely agreed with the original HGC evaluation, (94.3% by subjects, 91.8% by nerves), with no significant difference between evaluations (subjects: χ2 = 2.27, P = .132, nerves: χ2 = 0.98, P = .323).

DISCUSSION

MRN detection of HGCs is common in NA.

Ultrasound of the Ulnar Nerve: A Pictorial Review: Part 2: Pathological Ultrasound Findings

This is the second part of a two-part article in which we focus on the ultrasound (US) appearance of the pathological ulnar nerve (UN) and its main branches. Findings in a wide range of our pathological cases are presented with high-resolution US images obtained with the latest-generation US machines and transducers.

Imaging characteristics of posterior interosseous nerve syndrome

Posterior interosseous nerve syndrome (PINs) is a rare nerve compression syndrome that affects the deep branch of the radial nerve in the supinator muscle region. In this article, we aimed to report a case of a 58-year-old male who had clinical symptoms, electromyographic, ultrasound, and MRI features suggestive of PINs due to compressing the arcade of Frohse. He subsequently underwent surgical correlation at our hospital, and the clinical symptoms were improved significantly.

Non-invasive in vivo study of morphology and mechanical properties of the median nerve

The current literature studied the median nerve (MN) at specific locations during joint motions. As only a few particular parts of the nerve are depicted, the relevant information available is limited. This experiment investigated the morphological and biomechanical properties of the MN. The effects of the shoulder and wrist motions on MN were explored as well. Eight young healthy female individuals were tested with two-dimensional ultrasound and shear wave elastography (SWE). The morphological and biomechanical properties were examined in limb position 1, with the wrist at the neutral position, the elbow extended at 180°, and the shoulder abducted at 60°. In addition, the experiment assessed the differences among the wrist, forearm, elbow, and upper arm with Friedman's test and Bonferroni post hoc analysis. Two groups of limb positions were designed to explore the effects of shoulder movements (shoulder abducted at 90° and 120°) and wrist movements (wrist extended at 45° and flexed at 45°) on the thickness and Young's modulus. Differences among the distributions of five limb positions were tested as well. The ICC3, 1 values for thickness and Young's modulus were 0.976 and 0.996, respectively. There were differences among the MN thicknesses of four arm locations in limb position 1, while Young's modulus was higher at the elbow and wrist than at the forearm and upper arm. Compared to limb position 1, only limb position 4 had an effect on MN thickness at the wrist. Both shoulder and wrist motions affected MN Young's modulus, and the stiffness variations at typical locations all showed a downward trend proximally in all. The distributions of MN thickness and Young's modulus showed fold line patterns but differed at the wrist and the pronator teres. The MN in the wrist is more susceptible to limb positions, and Young's modulus is sensitive to nerve changes and is more promising for the early diagnosis of neuropathy.

Superficial Radial Neuropathy due to Anatomic Variation: A Case Report

Superficial radial neuropathy is a purely sensory neuropathy, usually caused by nerve entrapment in the distal forearm. We report a case of superficial radial neuropathy caused by the anomalous course of the superficial radial nerve, which was found to be spirally encircling the brachioradialis tendon in the distal forearm. To the best of our knowledge, this is the first report of an anatomical variant of the superficial radial nerve that causes neuropathy.

Ultrasound of the Ulnar Nerve: A Pictorial Review: Part 1: Normal Ultrasound Findings

This is the first of a two-part article in which we focus on the ultrasound (US) appearance of the normal ulnar nerve (UN) and its main branches. The detailed US anatomy of the UN course is presented with high-resolution US images obtained with the latest-generation US machines and transducers.

Ultrasound and magnetic resonance imaging neurography assessment of diagnostic criteria in patients with carpal tunnel syndrome using electrophysiological tests as gold standard: A prospective study

Objectives

Evaluating peripheral neuropathy mainly relies on physical examination, patient history, and electrophysiological studies. High-resolution ultrasound is a fast, noninvasive modality for dynamic nerve assessment that enables the length of the nerve to be examined. Magnetic resonance imaging is preferred for examining deeper nerves with a high contrast resolution; its use shows excellent benefit in patients with atypical presentation, equivocal diagnosis, suspected secondary causes, and postsurgical relapse. We aimed to assess the measurements and criteria for both ultrasound and magnetic resonance neurography for the diagnosis of carpal tunnel syndrome, based mainly on the three measurements assessed by Buchberger et al.

Methods

This prospective study was conducted to test diagnostic accuracy. Thirty-two patients who presented clinically with, and were diagnosed by electrophysiological tests as having, carpal tunnel syndrome participated. Superficial ultrasound of the wrist joint was performed on all participants, followed by magnetic resonance imaging within 1 week of ultrasonography.

Results

The three main parameters of cross-sectional area measurement, distal nerve flattening, and flexor retinaculum bowing indices showed positive occurrences of 93.7%, 59.4%, and 59.4%, respectively; 90.6% of patients had decreased nerve echotexture. The diagnostic ability of magnetic resonance imaging was decreased when cross-sectional area measurements were used: positive results were achieved in 81.2% of patients, but the positive results showing the distal tunnel nerve increased flattening and bowed flexor retinaculum slightly decreased to 56.2% for each. A high T2 signal of the median nerve was observed in 90.6% of patients. In an agreement analysis, we found a statistically significant difference that supported the use of ultrasound as a primary diagnostic modality for carpal tunnel syndrome. However, magnetic resonance imaging improved tissue characterization and was a good diagnostic modality, with a statistically significant difference, for cases of secondary carpal tunnel syndrome, detection of the underlying entrapping cause, and early abnormality detection in the innervated muscle.

Conclusions

Our results demonstrate that ultrasound examination can be used as the first imaging modality after physician evaluation, with results comparable to those of electrophysiological studies for evaluating carpal tunnel syndrome and determining its cause. Magnetic resonance neurography examination is the second step in detecting secondary causes in cases with suspected early muscle denervation changes that cannot be elicited by ultrasound or in cases with equivocal results.

Accessory head of flexor carpi radialis and abnormal course of the median nerve in the forearm

Background

The median nerve anatomy and its clinical presentation are crucial for surgeons to consider avoiding iatrogenic injury and performing effective surgical interventions.

Case Description

An atypical presentation of median nerve anatomy proximal to the carpal tunnel was found during cadaveric dissection. The median nerve was located deep to a uniquely double-headed flexor carpi radialis and curved medially around the tendons of the forearm to enter the carpal tunnel superficially.

Conclusion

The atypical presentation of median nerve anatomy can assist surgeons in adverse event reduction during surgeries such as carpal tunnel and pronator teres syndrome releases.

An Updated Review of Magnetic Resonance Neurography for Plexus Imaging

Magnetic resonance neurography (MRN) is increasingly used to visualize peripheral nerves in vivo. However, the implementation and interpretation of MRN in the brachial and lumbosacral plexi are challenging because of the anatomical complexity and technical limitations. The purpose of this article was to review the clinical context of MRN, describe advanced magnetic resonance (MR) techniques for plexus imaging, and list the general categories of utility of MRN with pertinent imaging examples. The selection and optimization of MR sequences are centered on the homogeneous suppression of fat and blood vessels while enhancing the visibility of the plexus and its branches. Standard 2D fast spin-echo sequences are essential to assess morphology and signal intensity of nerves. Moreover, nerve-selective 3D isotropic images allow improved visualization of nerves and multiplanar reconstruction along their course. Diffusion-weighted and diffusion-tensor images offer microscopic and functional insights into peripheral nerves. The interpretation of MRN in the brachial and lumbosacral plexi should be based on a thorough understanding of their anatomy and pathophysiology. Anatomical landmarks assist in identifying brachial and lumbosacral plexus components of interest. Thus, understanding the varying patterns of nerve abnormalities facilitates the interpretation of aberrant findings.

Preoperative electrodiagnostic studies and postoperative outcomes for ulnar mononeuropathy at the elbow: A systematic review

OBJECTIVE

To analyze the association between preoperative electrodiagnostic (EDX) studies and postoperative pain and functional outcomes following ulnar nerve decompression and/or transposition for ulnar neuropathy at the elbow (UNE).

LITERATURE SURVEY

Protocol was submitted and database search was conducted by an experienced librarian of all available studies in the English language from 1990 to June 8, 2022. Databases included Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, and Scopus.

METHODOLOGY

Inclusion criteria consisted of randomized controlled trials, prospective and retrospective longitudinal studies, and studies involving adults ≥18 years of age who underwent ulnar nerve decompression and/or transposition for UNE. Study quality and risk of bias were assessed using the National Heart, Lung, and Blood Institute (NHLBI) Study Quality of Assessment Tool. Certainty in evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. A meta-analysis was not performed.

SYNTHESIS

A total of 289 studies were screened, and 8 retrospective cohort studies met inclusion criteria comprising 762 patients. A decreased or absent preoperative sensory nerve action potential amplitude (SNAP) showed significance with worse postoperative outcomes. The presence of preoperative conduction block showed significance in higher quality studies. There was limited evidence for slow preoperative motor conduction velocities or preoperative electromyography (EMG) abnormalities and postoperative outcomes. Overall quality assessment demonstrated that two studies had "good," four "fair," and two "poor" quality of evidence. Certainty in evidence was "low" due to risk of bias.

CONCLUSIONS

A decreased or absent preoperative ulnar SNAP may predict worse postoperative outcomes. Per higher quality studies, preoperative conduction block at the elbow may also predict worse postoperative outcomes. Careful interpretation is required with a full understanding of the limited evidence, risk of bias, and low certainty in evidence to support the use of preoperative EDX to predict postoperative outcomes in UNE.

Ultrasound-guided median nerve hydrodissection of pronator teres syndrome: a case report and a literature review

Aim of the study

To describe the sonographic appearance of pronator teres syndrome and the role of ultrasound-guided hydrodissection for its management.

Case description

Pronator teres syndrome is a well-known compressive neuropathy of the median nerve between the two heads of pronator teres. However, the clinical presentation of this syndrome can be indolent with vague pain at the proximal volar forearm leading to a delay in diagnosis. We describe our experience in the management of pronator teres syndrome in a healthy young badminton player with ultrasound-guided median nerve hydrodissection. We highlight the clinical presentation, the role of dynamic Ultrasound scan (USS) in the diagnosis and effective treatment of pronator teres syndrome.

Conclusions

In conclusion, managing PTS can be challenging, and this case highlights the importance of ultrasound-guided hydrodissection, when conservative measures have failed to improve the symptoms. Further studies are required to assess and compare the long-term outcomes of these interventions.

Strike Out: A Case Report of Glioblastoma in a Collegiate Softball Player

A 20-year-old female, right-hand-dominant Division I softball player, presented to her pre-participation exam endorsing numbness that started in her left thumb and had progressed to involve her entire hand and left medial elbow. She had no change in her physical health over the past year prior to presentation and denied injury illness or trauma to the left upper extremity or neck. She reported no change in her softball off-season training regimen or equipment. Exam exhibited decreased sensation in C6, C7, and C8 dermatomes and weakness in the C8 myotome. Magnetic resonance angiography (MRA) displayed a right parietal lobe mass which biopsy confirmed as glioblastoma multiforme (GBM). GBM, also known as glioblastoma or grade 4 astrocytoma is an aggressive form of cancer that can affect the brain and spinal cord. Despite being the most common malignant primary brain tumor in adults, current treatment is mostly palliative. Treatment for this student-athlete included surgery, radiation, and chemotherapy. The selection of aggressive treatment including excision of the tumor was largely elected due to her age. She received chemotherapy with temozolomide in conjunction with radiation for a total of nine months. Following treatment, she worked with physical therapy to help improve her functional deficits, caused both by the tumor as well as the excision. Additionally, psychological and emotional support was provided to the patient during the course of the diagnosis and treatment of her athletics career-ending diagnosis. The same support services were also extended to the entirety of her teammates as well as her family members. This case outlines the diagnosis, treatment, and challenges of GBM in a Division I softball athlete including the challenges of providing emotional support for an athlete living away from home while being diagnosed with a life and athletics-career altering condition.

Possible Points of Ulnar Nerve Entrapment in the Arm and Forearm: An Ultrasound, Anatomical, and Histological Study

Background: Ulnar nerve entrapment is one of the most common entrapment neuropathies, usually occurring in the cubital tunnel of the elbow and in Guyon’s canal of the wrist. However, it can also occur at other anatomical locations. Purpose: Our aim was to review other possible locations of ulnar nerve entrapment in an ultrasound and anatomical study. Material and Methods: Eleven upper limbs from eight adult corpses were ultrasonographically examined and subsequently dissected in a dissection laboratory. Four specific anatomical points were analysed, and any anatomical variations were documented. Moreover, six samples of the nerve were taken for histological analysis. Results: Distinct anatomical relationships were observed during ultrasound and dissection between the ulnar nerve and the medial intermuscular septum, the triceps aponeurosis, Osborne’s fascia at the elbow, the arcuate ligament of Osborne and the intermuscular aponeurosis between the flexor carpi ulnaris and the flexor digitorum superficialis muscles. A statistical study showed that these locations are potential areas for ulnar nerve compression. In addition, a fourth head of the triceps brachii muscle was found in some specimens. Conclusion: Results demonstrate that ultrasound is a good tool to investigate ulnar nerve entrapment neuropathy and to identify other anatomical points where the nerve can remain compressed.

Acute and Chronic Elbow Disorders

Elbow pain is very common and can be due to many pathologic conditions. After radiographs are obtained, advanced imaging is often necessary. Both ultrasonography and MR imaging can be used to evaluate the many important soft-tissue structures of the elbow, with each modality having advantages and disadvantages in certain clinical scenarios. Imaging findings between the two modalities often correlate. It is important for musculoskeletal radiologists to understand normal elbow anatomy and how best to use ultrasonography and MR imaging to evaluate elbow pain. In this way, radiologists can provide expert guidance to referring clinicians and best guide patient management.

Etiological study of superficial radial nerve neuropathy: series of 34 patients

Objectives

Superficial radial nerve (SRN) neuropathy is a rare focal neuropathy leading to pain and paresthesia of the dorsolateral aspect of the hand. Reported causes include trauma, extrinsic compression, or it may be idiopathic. We describe the clinical and electrodiagnostic (EDX) features of 34 patients with SRN neuropathy of varied etiology.

Methods

This is a retrospective study of patients with upper limb neuropathy referred for EDX studies who were found to have SRN neuropathy based on clinical and EDX findings. Twelve patients also had ultrasound (US) evaluations.

Results

Decreased pinprick sensation was noted in the distribution of the SRN in 31 (91%) patients, and a positive Tinel's sign was observed in 9 (26%). Sensory nerve action potentials (SNAPs) were not recordable in 11 (32%) patients. Of the patients who had a recordable SNAP, the latency was delayed, and the amplitude was decreased in all cases. Of the 12 patients who underwent US studies, 6 (50%) had an increased cross-sectional area of the SRN at or immediately proximal to the site of injury/compression. A cyst was located adjacent to the SRN in 2 patients. The most common cause of SRN neuropathy was trauma in 19 (56%) patients, of which 15 were iatrogenic. A compressive etiology was identified in 6 patients (18%). No specific etiology was detected in 10 patients (29%).

Conclusion

This study is aimed at raising the awareness among surgeons about the clinical features and varied causes of SRN neuropathy; such knowledge may potentially lessen iatrogenic causes of injury.

Ultrasound as a Useful Tool for a Peripheral Nerve Surgeon: Examples in Clinical Practice

BACKGROUND

 Peripheral nerve surgeons often require additional imaging for examination, diagnostic testing, and preoperative planning. Point-of-care ultrasound (US) is a cost-effective, accessible, and well-established technique that can assist the surgeon in diagnosing and treating select peripheral nerve pathologies. With this knowledge, the properly trained surgeon may perform US-guided nerve blocks to help accurately diagnose and treat causes of neuropathic pain. We offer this paper, not as an exhaustive review, but as a selection of various peripheral nerve pathologies, which the senior author treats, and their associated US examination findings. Our goal is to encourage other peripheral nerve surgeons to incorporate US into their practices.

METHODS

 We provide various cases from our outpatient peripheral nerve clinic demonstrating relevant US anatomy. We also review techniques for US guided nerve blocks with relevant anatomic landmarks.

RESULTS

 US imaging successfully assisted in identification and injection techniques for various peripheral nerve pathologies in a surgeon's practice. Examples were presented from the neck, trunk, upper extremity, and lower extremity.

CONCLUSION

 Our review highlights the use of US by a peripheral nerve surgeon in an outpatient private practice clinic to diagnose and treat select peripheral nerve pathologies. We encourage reconstructive surgeons to add US to their arsenal of diagnostic tools.

Role of dynamic ultrasound in assessment of the snapping elbow and distal biceps tendon injury

Introduction

Ultrasound is useful in assessing patients with snapping syndromes around the elbow joint. The dynamic nature of the examination allows for direct visualisation of the underlying causative factor.Topic description: We discuss the role of dynamic ultrasound in assessing various snapping syndromes around the elbow, such as ulnar nerve instability, snapping triceps and less commonly, snapping brachialis. Ultrasound is also useful in evaluating the distal biceps tendon, particularly in differentiating partial from complete tendon injury.

Discussion

Ulnar nerve instability and snapping triceps can be assessed via a medial approach with the transducer placed transversely between the medial epicondyle and the olecranon. In ulnar nerve instability, the nerve can be seen crossing over the medial epicondyle on elbow flexion. In snapping triceps syndrome, both the ulnar nerve and the distal triceps can be seen dislocating over the medial epicondyle. Dynamic assessment of the distal biceps tendon using a lateral approach minimises anisotropy artefact often seen on the anterior approach. Passive pronation and supination of the forearm will reveal little or no movement in a completely torn tendon whereas moving tendon fibres will be appreciated in partial tears. In a snapping brachialis, the medial portion of brachialis will be seen abnormally translocating anterolateral to the medial border of the trochlea during elbow flexion and snapping back into its normal position on elbow extension.

Conclusion

Dynamic ultrasound of the elbow is valuable in diagnosing patients with snapping sensations around the joint and in evaluating the integrity of the distal biceps tendon.

Hydrodissection for Carpal Tunnel Syndrome: A Systematic Review

ABSTRACT

Hydrodissection is an ultrasound-guided technique that has received more attention recently for its role in nerve entrapment syndromes. The purposes of this systematic review were to evaluate the safety and effectiveness of hydrodissection in carpal tunnel syndrome and to investigate the ideal parameters for injectate type, dosage, volume, and frequency; injection approach and technique; as well as operator experience and training required. We searched the Embase, MEDLINE, and PubMed databases with supplemental searches in the CINAHL, Web of Science, and Google Scholar databases for relevant randomized controlled trials. Primary outcome measures were adverse outcomes and clinical effectiveness. Six randomized controlled trials involving 356 wrists were included. All studies used ultrasound guidance in their interventions. No safety-related adverse outcomes were found, although not all studies declared this. Only one study was placebo controlled and revealed symptomatic as well as functional improvements at 6 mos, whereas the rest investigated hydrodissection with different injectate types. We concluded that nerve hydrodissection for carpal tunnel syndrome can be safely performed under ultrasound guidance. However, it is unclear whether the hydrodissection mechanism truly causes improvements in clinical outcomes. We were also unable to draw conclusions regarding the ideal procedure-related parameters. We recommend that future work should not only investigate safety and clinical effectiveness but also attempt to clarify the ideal procedure-related parameters.

Ultrasonographic Evaluation of Peripheral Nerves: Technical Considerations

Advances in ultrasonographic (US) technology featuring high-resolution transducers have revolutionized US over recent years as a modality increasingly used in the evaluation of musculoskeletal structures and peripheral nerves. A wide variety of nerve pathologies can be detected, such as neoplastic and tumorlike lesions, entrapment syndromes, posttraumatic injuries, and inflammatory conditions. US can serve as an imaging tool for guiding percutaneous treatments, such as injection therapies or hydrodissection, and assist with perioperative nerve marking and visualization of peripheral nerves in the operating room. This article describes the normal US appearance of peripheral nerves, US imaging techniques, common peripheral nerve pathologies, and interventional applications.

Aberrant Neuronal Activity in a Model of Work-Related Upper Limb Pain and Dysfunction

Work-related musculoskeletal disorders associated with intense repetitive tasks are highly prevalent. Painful symptoms associated with such disorders can be attributed to neuropathy. In this study, we characterized the neuronal discharge from the median nerve in rats trained to perform an operant repetitive task. After 3-weeks of the task, rats developed pain behaviors and a decline in grip strength. Ongoing activity developed in 17.7% of slowly conducting neurons at 3-weeks, similar to neuritis. At 12-weeks, an irregular high frequency neuronal discharge was prevalent in >88.4% of slow and fast conducting neurons. At this time point, 8.3% of slow and 21.2% of fast conducting neurons developed a bursting discharge, which, combined with a reduction in fast-conducting neurons with receptive fields (38.4%), is consistent with marked neuropathology. Taken together, we have shown that an operant repetitive task leads to an active and progressive neuropathy that is characterized by marked neuropathology following 12-weeks task that mainly affects fast conducting neurons. Such aberrant neuronal activity may underlie painful symptoms in patients with work-related musculoskeletal disorders. PERSPECTIVE: Aberrant neuronal activity, similar to that reported in this study, may contribute to upper limb pain and dysfunction in patients with work-related musculoskeletal disorders. In addition, profiles of instantaneous frequencies may provide an effective way of stratifying patients with painful neuropathies.

Outcome of Surgical Treated Isolated Pronator Teres Syndromes-A Retrospective Cohort Study and Complete Review of the Literature

PURPOSE

This study aims to elucidate the occurrence of postoperative carpal tunnel syndrome (CTS), the functional outcome of patients with primary pronator teres syndrome (PTS), and review complete literature regarding this topic.

MATERIAL AND METHODS

A retrospective chart review was conducted in patients with PTS at a single center. In all patients, a numeric Visual Analog Scale (VAS) score, Pinch-Test, Jamar hand dynamometer test (JAMAR), and the Disabilities of the Arm Shoulder and Hand (DASH) score were analyzed preoperatively and at final follow-up to assess outcome. Additionally, a complete review of the literature was performed, including all data dealing with pronator teres syndrome.

RESULTS

Ten female and two male patients were included with a mean age of 49 years. Significant improvement in DASH and numeric VAS was detected at latest postoperative follow-up. In three patients, clinical signs of CTS pathology were detected during the follow-up period. One patient needed to be treated surgically, and in the other two patients, a conservative management was possible. In one patient (8%), a PTS recurrence was detected. All patients presented satisfied at latest follow-up.

CONCLUSION

In one-fourth of our patients, a CTS occurred during the follow-up period. Therefore, focusing on double-crush syndrome in unclear or mixed symptoms is necessary to avoid multiple operations. Furthermore, it seems that assessment with NCV is not enough for diagnosing PTS; therefore, further research is needed to clarify this problem.

Surgical decompression of an accessory bicipital aponeurosis associated with median neuropathy in the antecubital fossa: A case report

Background:

Accessory muscles in the arm are well-known anatomical variants which have been hypothesized as sources of neurovascular compression syndromes. We report a rare presentation of neuropathy secondary to an accessory biceps aponeurosis causing compression of the median nerve in the antecubital fossa.

Case Description:

A 65-year-old man presented with a 5-year history of numbness and pain associated with arm flexion. Electromyography was normal and exam revealed mild weakness in the median nerve distribution; however, magnetic resonance imaging demonstrated an accessory biceps tendon overlaying the median nerve in the antecubital fossa. The patient underwent surgical decompression of the median nerve with detachment of the accessory tendon resulting in clinical improvement.

Conclusion:

Anomalous biceps musculature should be considered in the workup and treatment of proximal median neuropathy.

MRI Evaluation of Various Elbow, Forearm, and Wrist Neuropathies: A Pictorial Review

Upper extremity entrapment neuropathies are common and can cause pain, sensory loss, and muscle weakness leading to functional disability. We conducted a retrospective review from January 2007 until March 2020 of the magnetic resonance imaging (MRI) features of intrinsic and extrinsic causes of wrist, forearm, and elbow neuropathies of 637 patients who received a diagnosis of neuropathy by means of clinical and electrodiagnostic testing. We discuss cases with varying intrinsic and extrinsic nerve pathologies, including postoperative examples, affecting the median, radial, and ulnar nerve.Our collection of cases demonstrates a diversity of intrinsic and extrinsic causative factors. Intrinsic pathologies include neuritis as well as tumors arising from the nerve. Extrinsic causes resulting in nerve entrapment include masses, acute and chronic posttraumatic cases, anatomical variants, inflammatory and crystal deposition, calcium pyrophosphate deposition disease, and dialysis-related amyloidosis. Finally, we review postsurgical cases, such as carpal tunnel release and ulnar nerve transposition.Although upper extremity neuropathies tend to have a typical clinical presentation, imaging, particularly MRI, plays a vital role in evaluating the etiology and severity of each neuropathy and ultimately helps guide clinical management.

Elbow Imaging: Variants and Asymptomatic Findings

One of the key principles in the interpretation of radiology images is the ability to differentiate between normal and abnormal findings. This article provides a comprehensive overview of normal structures and anatomical variants occurring around the elbow including potential diagnostic pitfalls. We discuss frequently observed anatomical variants found in routine clinical practice associated with osseous, ligamentous, musculotendinous, and neurovascular structures at the elbow that may simulate pathology or predispose to symptoms under specific circumstances.

Possible points of compression of the ulnar nerve: Tricks and traps that await clinicians from an anatomical point of view

The ulnar nerve can be subject to numerous types of compression. The most common are cubital tunnel and ulnar tunnel syndromes, but there are many others with more uncommon etiologies. The existence of additional communicating branches, median nerve involvement, various types of injuries, and unusual anatomical variations can be a challenge for both diagnosis and treatment. This review presents a comprehensive depiction of ulnar nerve entrapment syndromes with particular reference to their anatomical background, risk factors, and clinical evaluation. Even common disorders can result from atypical morphological changes. It is important to be familiar with them as it is a key ability in daily medical practice.

Imaging of Elbow Injuries

Familiarity with throwing mechanics during elbow range of motion allows accurate diagnosis of sports-related elbow injuries, which occur in predictable patterns. In addition, repetitive stress-related injuries are often clinically apparent; however, imaging plays an important role in determining severity as well as associated injuries that may affect clinical management. A detailed understanding of elbow imaging regarding anatomy and mechanism of injury results in prompt and precise treatment.

Differential Diagnosis for the Painful Tingling Arm

ABSTRACT

The painful tingling arm is a common presenting complaint for the musculoskeletal physician. The differential diagnosis for upper-extremity pain associated with paresthesias will be the focus of this review. Symptoms are often neurologic in etiology, originating from the spinal cord, nerve root(s), brachial plexus, or peripheral nerve(s). Localizing the pathology starts with a comprehensive understanding of neuromuscular anatomy. It also is imperative to understand the function of these respective structures. The differential diagnosis can be narrowed with a thorough history, including an assessment of sport-specific risk factors, along with a comprehensive physical examination and functional assessment. It is important to determine the sensory distribution of the patient's symptoms. If weakness also is present, the affected muscles must be identified. While the diagnosis can often be made clinically, electrodiagnostics, magnetic resonance imaging, and ultrasound can be used as needed for confirmation and more specific localization. Nonneurologic structures also may be causative or contributory to the patient's symptoms and also should be considered.

Review Article "Spotlight on Ultrasonography in the Diagnosis of Peripheral Nerve Disease: The Evidence to Date"

Neuromuscular ultrasound is rapidly becoming incorporated into clinical practice as a standard tool in the assessment of peripheral nerve diseases. Ultrasound complements clinical phenotyping and electrodiagnostic evaluation, providing critical structural anatomical information to enhance diagnosis and identify structural pathology. This review article examines the evidence supporting neuromuscular ultrasound in the diagnosis of compressive mononeuropathies, traumatic nerve injury, generalised peripheral neuropathy and motor neuron disease. Extending the sonographic evaluation of nerves beyond simple morphological measurements has the potential to improve diagnostics in peripheral neuropathy, as well as advancing the understanding of pathological mechanisms, which in turn will promote precise therapies and improve therapeutic outcomes.

Health economic evaluation of different treatment strategies for peripheral entrapment mononeuropathies: a systematic review

Introduction: In this era of cost-conscious health systems, it is of utmost importance to identify and establish the most cost-effective treatment option. However, in the case of peripheral entrapment mononeuropathies there is alack of data regarding economically effective treatment strategies. Therefore, the objective was to conduct an economic evaluation including both costs and benefits of various treatment strategies applied to peripheral entrapment mononeuropathies to estimate the relative cost-effective treatment regimens.Areas covered: Over the 19 years, seven excellent-high quality economic evaluations of three types of peripheral entrapment mononeuropathies were identified in four countries. Our findings showed that surgery was the most cost-effective therapy followed by same cost efficacy of infiltrative therapy and conservative therapy for peripheral entrapment mononeuropathies. However, the fact that surgery was the most common comparator (n = 6) in our selected studies cannot be neglected.Expert opinion: Due to huge methodological variability, the finding of surgery as the cost-effective treatment strategy remains tentative and the decision about the most suitable clinical and cost-effective therapy should be individualized from case to case. Moreover, the economic evaluation of all possible treatment strategies for peripheral entrapment mononeuropathies over alonger period of analysis is required in future studies.

Ultrasonography evaluation of the normal ulnar nerve in adult: Comparison of the cross-sectional area at elbow extension and flexion

Background

Cross-sectional area (CSA) measurement of the ulnar nerve in the adult population by using ultrasonography (US) at elbow extension and flexion has previously been reported, but not much evidence showed a significant difference between elbow extension and flexion position.

Purpose

To compare the ulnar nerve CSA between elbow extension and flexion position.

Methods

A comparative cross-sectional study was conducted by involving 36 healthy adults with normally functioning ulnar nerve proven by Nerve Conduction Study (NCS) or Electroneurography. The ulnar nerve CSA was measured on each elbow by using US at the level of the medial epicondyle, 2 cm distal and 2 cm proximal from the medial epicondyle.

Results

The average ulnar nerve CSA at the medial epicondyle, 2 cm distal and proximal to the medial epicondyle at elbow extension respectively were 5.95 ± 0.74 mm2, 6.27 ± 0.92 mm2, and 5.92 ± 0.73 mm2. At elbow flexion, the average ulnar nerve CSA at the positions was 5.70 ± 0.83 mm2, 5.23 ± 0.87 mm2, dan 5.73 ± 0.71 mm2 respectively. The CSA of the ulnar nerve at elbow extension was significantly larger compared to the flexion position in the three areas observed in this study (p < 0.001).

Conclusion

The CSA of the ulnar nerve at elbow extension position was larger compared to the flexion position. Elbow position should be considered in measuring CSA of the ulnar nerve.

[Imaging of the hand : What should be considered regarding the nerves?]

BACKGROUND

Peripheral nerve disorders of the hand and wrist are most commonly caused by entrapment neuropathies, while traumatic nerve injuries and neoplasms are less common.

OBJECTIVES

The indication for additional imaging methods and different imaging options, especially in patients with atypical symptoms or remaining unclear etiology of symptoms after completion of standard diagnostics, are presented.

MATERIALS AND METHODS

The imaging methods magnetic resonance (MR) neurography and neurosonography are introduced, and typical findings as well as diagnostic pitfalls are presented.

RESULTS

The diagnostic gold standard, which comprises a past medical history, neurologic examination and electrophysiology, can often establish the diagnosis. Imaging methods, especially MR neurography and neurosonography, are gaining increasing importance in the diagnostic workup of atypical neuropathies, as well as in the determination of the exact lesion location and spatial lesion extension, especially for surgical planning. Recent technical advances allow high-resolution depiction of small distal terminal nerve branches.

CONCLUSIONS

MR neurography allows for the high-resolution depiction of peripheral nerves of the hand and wrist. It can confirm the diagnosis of neuropathy, identify the exact lesion location, and rule out any differential diagnoses. Neurosonography is a time- and cost-efficient alternative diagnostic method.

Clinico-radiological review of peripheral entrapment neuropathies - Part 1 upper limb

PURPOSE

This article aims to review the pertinent anatomy, etiopathogenesis, current clinical and radiological concepts and principles of management in case of upper limb entrapment neuropathies.

METHODS

The review is based on critical analysis of the existing literature as well as our experience in dealing with entrapment neuropathies.

RESULTS

Entrapment neuropathies of the upper limb peripheral nerves are common conditions that are often misdiagnosed because of their varying clinical presentations and lack of standardized diagnostic methods. Clinical assessment and electrodiagnostic studies have been the mainstay; however, imaging techniques have provided newer insights into the pathophysiology of these entities, leading to a paradigm shift in their diagnosis and management. The current best practice protocols for entrapment syndromes are constantly evolving with increasing emphasis on the role high-resolution ultrasound and magnetic resonance imaging. Many imaging criteria are described and we have tried to present the most validated measurements for diagnosing entrapment neuropathies.

CONCLUSION

It is imperative for a clinical radiologist to be familiar with the etiopathogenesis and clinical features of these conditions, in addition to being thorough with the anatomy and the latest imaging strategies.

Percutaneous Radiofrequency Ablation of the Posterior and Anterior Interosseous Nerves for Chronic Wrist Pain: A Novel Technique

The treatment of chronic wrist pain, due to posttraumatic, degenerative, or inflammatory arthritis, is challenging to adequately manage. The ideal surgical procedure should preserve wrist mobility and provide long-lasting pain relief. In this regard, denervation aims to decrease wrist pain by interrupting sensory innervation, without impairing motor function, and avoids the need for postoperative immobilization to decrease the risk of stiffness. For these reasons, denervation is particularly attractive as a possible treatment for chronic wrist pain. Our aim was to describe our novel technique for partial percutaneous wrist denervation, performed by radiofrequency ablation of the posterior and anterior interosseous nerves, and to report on the prospective outcomes over a 1-year follow-up for 3 patients (4 wrists) treated as of March 2019. The technique is performed on an outpatient basis and does not require postprocedure wrist immobilization or restriction in activities of daily living or work. Findings at the 1-year follow-up indicate that partial denervation improved grip strength, provided pain relief, maintained wrist motion, and improved subjective report of disabilities of the arm, shoulder, and hand. One patient did not report a benefit of the procedures, with other patients being very satisfied. Our percutaneous procedure is an evolution of the traditional partial denervation technique, providing advantages of being less invasive, not requiring restriction of movement or activities in the postoperative phase, can be performed on an out-patient basis, and does not preclude the subsequent use of invasive surgical procedures, as needed.

Conditions and Injuries Affecting the Nerves Around the Elbow

Sports-related peripheral neuropathies account for 6% of all peripheral neuropathies and most commonly involve the upper extremity. The routes of the median, radial, and ulnar nerves are positioned in arrangements of pulleys and sheaths to glide smoothly around the elbow. However, this anatomic relationship exposes each nerve to risk of compression. The underlying mechanisms of the athletic nerve injury are compression, ischemia, traction, and friction. Chronic athletic nerve compression may cause damage with moderate or low pressure for long or intermittent periods of time.

Comprehensive Update of Elbow Magnetic Resonance Imaging

We present a comprehensive update of elbow magnetic resonance imaging, detailing the complex anatomy and pathology of the elbow. A variety of pathologies may affect the elbow joint, and many of the symptoms overlap. As such, magnetic resonance imaging of the elbow serves as an invaluable clinical tool for the clinician in the diagnosis and management of patients presenting with elbow pain.

Imaging of the Hand and Wrist

Imaging plays a key role in the evaluation and treatment planning of hand and wrist injuries in athletes. Depending on the suspected injury, a combination of conventional radiographs, computed tomography, magnetic resonance imaging, magnetic resonance arthrography, and/or ultrasound may be indicated. This article reviews the strengths and limitations of these imaging modalities and how they can be utilized in commonly encountered clinical questions.

Acupotomy for nerve entrapment syndrome: A systematic review protocol

BACKGROUND

Acupotomy has been widely used to treat nerve entrapment syndrome. But its efficiency has not been scientifically and methodically evaluated. The aim of this study is to evaluate the efficacy and safety of the acupotomy treatment in patients with nerve entrapment syndrome.

METHODS

Fifteen databases will be searched from inception to Dec 2019. We will include randomized controlled trials (RCTs) assessing acupotomy for nerve entrapment syndrome. All RCTs on acupotomy or related interventions will be included. Study inclusion, data extraction and quality assessment will be performed independently by 2 reviewers. Assessment of risk of bias and data synthesis will be performed using RevMan 5.3 software. Cochrane criteria for risk-of-bias will be used to assess the methodological quality of the trials.

RESULTS

This study will provide a high-quality synthesis of pain VAS and functional disability or the quality of life, the success treatment rate, the recurrent rate and the complications rate to assess the effectiveness and safety of acupotomy for nerve entrapment syndrome patients.

CONCLUSION

This systematic review will provide evidence to judge whether acupotomy is an effective intervention for patients with nerve entrapment syndrome.

PROSPERO REGISTRATION NUMBER

CRD42018109086.

MR imaging of the postsurgical cubital tunnel: an imaging review of the cubital tunnel, cubital tunnel syndrome, and associated surgical techniques

Ulnar nerve compression at the elbow, specifically the cubital tunnel, is the second most common upper extremity compression neuropathy. Many patients presenting with compression symptoms will subsequently undergo surgical intervention. We review the open surgical treatment of cubital tunnel syndrome and review the expected postoperative imaging appearance of those treatments on magnetic resonance imaging (MR), including: simple or in situ decompression, medial epicondylectomy, and anterior transposition, including subcutaneous, intramuscular, and submuscular variants. We discuss the relevant anatomy of the presurgical cubital tunnel and common sites and causes of ulnar nerve compression at and about the cubital tunnel. The imaging appearance of the preoperative and postoperative ulnar nerve and postoperative complications are reviewed.

Imaging in the diagnosis of ulnar nerve pathologies-a neoteric approach

The ulnar nerve is a branch of the C8 and T1 nerve roots and arises from the medial cord of the brachial plexus. It supplies the intrinsic muscles of the hand and assists the median nerve in functioning of the flexors. Also known as the musician’s nerve, it is the second most common nerve involved in compressive neuropathy following the median nerve. Common sites of entrapment include cubital tunnel at the elbow, the ulnar groove in the humerus and the Guyon’s canal at the wrist. Patients present with altered sensation in the ulnar fourth and the fifth digit and the medial side of arm with loss of function of intrinsic muscles of the hand, the flexor carpi ulnaris and ulnar fibres of flexor digitorum superficialis in more severe cases. Diagnosis relies on clinical examination, electrodiagnostic studies and imaging findings. Plain radiographs are used to identify fracture sites, callus, or tumours as cause of compression. Technological advances in ultrasonography have allowed direct visualisation of the involved nerve with assessment of exact site, extent and type of injury. It yields unmatched information about anatomical details of the nerve. MR imaging adds to soft tissue details and helps in characterising the lesion. This pictorial review aims to illustrate a wide spectrum of causes of ulnar neuropathies as seen on ultrasound and MRI and emphasises upon the importance of imaging modalities in the diagnosis of neuropathies.

Sonographic evaluation of uncommonly assessed upper extremity peripheral nerves: anatomy, technique, and clinical syndromes

Targeted ultrasound of the median, ulnar, and radial nerves is a well-established technique for suspected upper extremity peripheral neuropathy. However, sonographic imaging of the brachial plexus and smaller peripheral nerve branches is more technically difficult and the anatomy is less familiar to many radiologists. As imaging techniques improve, many clinicians refer patients for imaging of previously less-familiar structures. In addition, some patients may present with injuries that could involve local neurovascular structures. Finally, patients presenting with isolated peripheral neuropathies may be referred for perineural injections with local anesthetic for diagnostic purposes, or steroid for therapeutic reasons. This requires sonologists to have a firm understanding of the courses of these nerves and the surrounding anatomic landmarks that can be used to accurately identify and characterize them. We discuss clinical syndromes referable to specific peripheral nerve branches in the upper extremity, the relevant anatomy, and sonographic technique.