Detection of peripheral nerve pathology: comparison of ultrasound and MRI

Bibliometric analysis of the 100 most cited articles on cubital tunnel syndrome

Background

The aim of this study was to analyze the 100 most cited articles (T100) on Cubital Tunnel Syndrome (CuTS).

Methods

T100 articles were identified using the Web of Science database with the keyword cubital tunnel syndrome on January 10, 2024. Bibliometric analysis included information such as article title, total number of citations, number of authors, author names, country of publication, year of publication, type of publication, subject covered, journal publishing, h-index of publishing journals, Q classification, and impact factor.

Results

The number of citations for T100 articles ranged between 28 and 183. Journal of Hand Surgery - American Volume (n = 28) was the journal with the highest number of T100 articles. In the comparison between countries, the United States of America (n = 55) was represented by the highest number of articles. The evaluation of the main topics covered in the articles showed that surgical treatment (n = 64) was the main topic in the majority of T100 articles.

Conclusion

The results of this study provide insight into the scientific community's interest in CuTS. This study can be a guide for further research and potential solutions for CuTS.

Imaging for inflammatory neuropathies

Inflammatory neuropathies comprise a heterogeneous group of conditions united by inflammation-mediated damage to peripheral nerves and their vasa nervorum. Although classification, diagnosis and management are largely based on clinical features, electrodiagnostic and laboratory examinations, imaging studies play an important supporting role. Ultrasound and MRI are the two modalities used for imaging peripheral nerves. The two techniques differ in the clinical context of application, the information provided and the diagnostic performance. This narrative review aims to provide guidance on when and how to use ultrasound or MRI in patients with inflammatory neuropathies, highlighting their respective strengths and pitfalls, and how to combine these imaging modalities to enhance their usefulness in the diagnostic-therapeutic management of these far from rare conditions.

Electrodiagnostic Assessment of Peri-Procedural Iatrogenic Peripheral Nerve Injuries and Rehabilitation

Iatrogenic nerve injuries are a significant concern for medical professionals and the patients affected. Peri-procedural nerve injuries result in functional deficits associated with pain and disability. The exact pathophysiology and etiology of peri-procedural nerve injuries are complex and often elude providers. The rates of injury to specific nerves are unclear and relate to both procedural and patient specific risk factors. Initial classification of the nerve injury into neurapraxia, axonotmesis, mixed nerve injury, or possible complete transection (neurotmesis) guides rehabilitation and management. Electrodiagnostic medical consultation at least four weeks post-injury, supplemented with nerve imaging (ultrasound and magnetic resonance imaging), can allow for accurate nerve injury classification. Supplemented with nerve imaging and detailed clinical evaluation, treatment, recovery and rehabilitation can be maximized. Recognizing nerves at risk associated with medical and surgical procedures can facilitate injury avoidance and early diagnosis. If a nerve injury is incomplete, in an optimized physiologic milieu (good glucose control, smoking cessation, etc.), there is a good potential for spontaneous (total or partial) improvement over time. Surgical referral should be considered for severe nerve injuries within 6 months, especially if there is concern for neurotmesis, and/or deteriorating nerve function. This review gives guidance for approaching peri-procedural peripheral nerve injuries, including the timing and the role of electrodiagnostic medical consultation including serial electrodiagnostic studies in management and rehabilitation.

Evaluation of MRI features of neuromas in oncological amputees, and the relation to pain

OBJECTIVE

The impact of time on neuroma growth and morphology on pain intensity is unknown. This study aims to assess magnetic resonance imaging (MRI) differences between symptomatic and non-symptomatic neuromas in oncological amputees, and whether time influences MRI-detected neuroma dimensions and their association with pain.

MATERIAL AND METHODS

Oncological patients who underwent traditional extremity amputation were included. Post-amputation MRIs were assessed before decision for neuroma surgery. Chart review was performed for residual limb pain (numeric rating scale, 0-10) and the presence of neuropathic symptoms. Neuromas were classified as symptomatic or non-symptomatic, with neuroma size expressed as radiological neuroma-to-nerve-ratio (NNR).

RESULTS

Among 78 neuromas in 60 patients, the median NNR was 2.0, and 56 neuromas (71.8%) were symptomatic with a median pain score of 3.5. NNR showed no association with symptomatology or pain intensity but correlated with a longer time-to-neuroma-excision interval and a smaller nerve caliber. Symptomatic neuromas were associated with lower extremity amputation, T2 heterogeneity, and the presence of heterotopic ossification. Lower extremity amputation, T2 heterogeneity, perineural edema, and presence of heterotopic ossification were associated with more painful neuromas.

CONCLUSION

MRI features associated with symptomatic neuromas and pain intensity were identified. Awareness of the potential clinical significance of these imaging features may help in the interpretation of MRI exams and may aid clinicians in patient selection for neuroma surgery in oncological amputees.

Accuracy of ultrasound and MRI in the diagnosis of common peroneal nerve injuries

BACKGROUND

This study aimed to determine the accuracy of ultrasound (US) and MRI compared to intraoperative findings in patients who underwent surgery for their common peroneal nerve (CPN) injury.

METHODS

Patients who underwent surgical management of a CPN injury with preoperative US were reviewed. The status of the CPN as interpreted by the radiologist in the preoperative US and MRI were recorded. The intraoperative findings of the CPN were compared to the imaging findings. The CPN was classified as intact, partial injury, or complete transection. The location of the injury, and presence of a neuroma-in-continuity or stump neuroma were recorded. The sensitivity and specificity of US for diagnosis of a complete transection and an intact CPN were calculated.

RESULTS

Thirteen patients were included in this study. Preoperative US accurately diagnosed a complete transection in 3 out of 4 patients and an intact CPN in 4 out of 5 patients. MRI did not accurately identify the status of the CPN in any patients. US had 75% sensitivity and 78% specificity for detecting complete transection, and 80% sensitivity and 63% specificity for detecting an intact CPN. The level of injury was correctly identified in 7 out of 13 cases by US and 1 out of 8 cases by MRI. A neuroma was correctly identified in 7 of 11 cases by US and 1 out of 8 cases by MRI.

CONCLUSION

US has a high sensitivity and specificity when diagnosing CPN lesions and was more accurate than MRI.

Utility of ultrasound in the diagnosis and management of a radial nerve perineurioma in a pediatric patient

Background

Intraneural perineuriomas are tumors originating from the perineurial cells surrounding nerve sheath fascicles. Intraneural perineuriomas represent about 1% of peripheral nerve tumors and are often misdiagnosed due to their rarity. In this case, we report a pediatric patient with a radial nerve perineurioma, in which ultrasound played a key role in diagnosis.

Case Description

We present the case of a 4-year-old male with over 6 months of progressive left upper extremity weakness found to have chronic left radial neuropathy distal to the triceps branch of the radial nerve on electromyography/nerve conduction study. Ultrasound showed a well-defined fusiform hypoechoic mass of approximately 1.5 × 0.5 × 0.8 cm, with the radial nerve noted to enter and exit the mass. Magnetic resonance imaging (MRI) did not encompass the pathology. The mass was excised with small margins, and pathology was consistent with perineurioma. The resultant 3 cm gap was repaired through nerve grafting. Surveillance MRI showed no recurrence of the perineurioma over time.

Conclusion

Ultrasound served as a necessary adjunct in the workup of upper extremity weakness despite negative MRI findings. This imaging modality should be considered if there is high clinical suspicion of a peripheral nerve lesion.

Peripheral Nerve Imaging: MR Neurography versus High-Resolution US

"Just Accepted" papers have undergone full peer review and have been accepted for publication in Radiology. This article will undergo copyediting, layout, and proof review before it is published in its final version. Please note that during production of the final copyedited article, errors may be discovered which could affect the content.

High-Resolution US vs MR Neurography for Diagnosis of Upper Extremity Peripheral Nerve Disorders

"Just Accepted" papers have undergone full peer review and have been accepted for publication in Radiology. This article will undergo copyediting, layout, and proof review before it is published in its final version. Please note that during production of the final copyedited article, errors may be discovered which could affect the content. Background High-resolution imaging methods contribute important pathomorphological information in diagnosing peripheral nerve disorders, but their diagnostic roles remain unclear due to limited clinical evidence. Purpose To investigate the diagnostic performance of high-resolution nerve US (HRUS) and MR neurography (MRN). Materials and Methods This prospective observational, single-center cohort study included 800 patients referred for clinically suspected peripheral neuropathy of the upper extremity from November 2015 to February 2022. All patients underwent both HRUS and MRN, performed and interpreted independently by experienced neuroradiologists. Accuracy, sensitivity, and specificity of HRUS and MRN in diagnosing peripheral neuropathy correctly were calculated in reference to the final diagnosis, based on compound results of clinical, electrophysiological, imaging, and surgical/histopathological findings and compared by means of the McNemar's test and X2-Testing. Results In total 800 patients (431 male, 369 female; mean age 47.8 ± 16.5 years) were included. Overall, MRN provided higher accuracy (85.4% [95%CI: 82.7%, 87.8%] vs. 70.6% [95%CI: 67.3%, 73.8%], P<.001) and sensitivity (91.6% [95%CI: 89.1%,93.7%] vs. 68.7% [95%CI: 64.8%,72.3%], P<.001), while HRUS achieved higher specificity (76.0% [95%CI: 69.4%,81.9%] vs. 66.2% [95%CI: 59.1%,72.8%], P<.001) for diagnosing peripheral neuropathy correctly. Conclusion For diagnosing peripheral neuropathies of the upper extremity, MRN achieved higher accuracy and sensitivity while HRUS achieved higher specificity. See also the editorial by Deshmukh in this issue.

The Role of High-Resolution Ultrasound in the Diagnosis of Nerve Trauma New Perspective: A Preliminary Systematic Review and Meta-Analysis of the Recent Evidence

SUMMARY

Precise localization of peripheral nerve injuries and evaluation of their prognosis based on clinical and electrodiagnostic examinations are particularly challenging in the acute phase. High-resolution ultrasound (HRUS) may offer a viable and cost-effective imaging option for assessing the morphology of nerve injuries. Consequently, a systematic review and meta-analysis of studies on the use of ultrasound for diagnosing traumatic nerve injuries were conducted. A total of 15 studies were included, reporting the most recent findings on using HRUS in the diagnosis of traumatic nerve injury. These studies assessed the diagnostic test accuracy of ultrasound for the detection of traumatic nerve injury in 272 participants, with the cross-sectional area at the site of traumatic nerve injury also reported in 1,249 participants. The pooled sensitivity and specificity of the included studies were 92% confidence interval (CI) (0.89-0.95) and 86% CI (0.82-0.89), respectively. The positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 13.76 CI (1.41-134.34), 0.08 CI (0.03-0.18), and 286.23 CI (21.22-3,860.40), respectively. In the summary of the receiver operating characteristic curve, the area under the curve was 0.986, and the Q* index was 0.949. Based on the current literature, HRUS has shown promising results in addition to its availability and feasibility. HRUS can serve as a valuable complement to clinical and electrodiagnostic examinations for diagnosing traumatic peripheral nerve injuries. Further research is recommended to better understand the ultrasound characteristics of these injuries.

Comparison of ultrasound and magnetic resonance imaging of the median nerve's recurrent motor branch and the value of its diameter in diagnosing carpal tunnel syndrome

Background

Anatomical variations of the recurrent motor branch (RMB) are at risk of injury during carpal tunnel release procedures. Previous studies have visualized the RMB using ultrasound (US) and magnetic resonance imaging (MRI) but have not compared the imaging capabilities of the two. Previous investigations have overlooked two specific types of carpal tunnel syndrome (CTS): simultaneous compression of the median nerve and the RMB and isolated compression of the latter. This study aims to identify the best imaging method to prevent iatrogenic injury to the RMB by comparing US and MRI capabilities. It also aims to devise a new method for the comprehensive diagnosis of CTS by evaluating the initial diameter of the RMB (RMB-ID). Additionally, this study aims to gain insights into the distribution patterns of the different anatomic variations of the RMB in healthy individuals and patients through an analysis of these variations. A cross-sectional study was conducted.

Methods

Forty healthy adults subjected to bilateral US and MRI of the RMB were included in this study. The US and magnetic resonance images of each patient were subsequently compared. US imaging of the RMB was performed on 102 hands of healthy adults and 112 hands of patients with CTS. The cross-sectional area of the median nerve (MN-CSA) and RMB-ID were measured.

Results

US provided better visibility of the RMB than did MRI (P<0.05). No statistically significant difference was observed in the variation type composition of the RMB between the healthy and patient groups (P>0.05). The RMB-ID and the MN-CSA significantly differed between groups (P<0.001). The RMB-ID increased with the increase of the MN-CSA (R=0.842; P<0.001). The optimal cutoff point for diagnosing CTS of the RMB-ID was 0.85 mm, yielding a sensitivity of 83.0%, a specificity of 92.2%, and the area under the curve of 0.945. The MN-CSA was 0.115 cm2, with a sensitivity of 73.2%, a specificity of 96.1%, and an area under the curve of 0.923 [95% confidence interval (CI): 0.887-0.958]. No statistically significant difference was observed in the area under the receiver operator characteristic curve between the two diagnostic methods (P>0.05). The interexaminer reliability for the RMB-ID and the MN-CSA measurements was 0.983 (95% CI: 0.978-0.987) and 0.966 (95% CI: 0.955-0.974), respectively.

Conclusions

US outperformed MRI in visualizing the anatomical variations of the RMB. The RMB-ID was an accurate and valid indicator for comprehensive diagnosis of CTS.

Ultrasound for Postoperative and Iatrogenic Peripheral Nerve Lesions: What Do Radiologists Need to Know?

Iatrogenic nerve injuries are common and require an immediate accurate diagnosis to allow surgical treatment within a short window of opportunity. Targeted investigation using high-resolution ultrasound (US) allows an accurate diagnosis in the acute phase when electrophysiology has a limited role. By identifying the exact site of injury, mechanism, and type of nerve damage, US can help determine the prognosis of the lesion and the need for surgical management. This pictorial review discusses the role of high-resolution US in the work-up of iatrogenic nerve injuries, with an emphasis on US appearances and the clinical knowledge needed by the radiologist to provide solutions to clinical challenges.

Injury Patterns, Imaging Findings, and Prognosis for Muscle Strength Recovery in Surgical Infraclavicular Brachial Plexus Injuries

Purpose

Historically, infraclavicular brachial plexus injuries (IBPIs) were considered neuropraxic injuries that would improve with nonsurgical intervention. However, more recent studies suggest that these injuries may benefit from surgical intervention. The aims of this retrospective study were to (1) describe injury patterns and associated injuries of isolated, traumatic IBPIs, (2) evaluate the concordance of preoperative ultrasound and magnetic resonance neurography with surgical findings of patients who underwent surgical intervention for IBPIs, and (3) describe outcomes of surgical intervention for these injuries.

Methods

A total of 148 patients who underwent surgical intervention for traumatic injury to the IBP by one of three hand/upper-extremity fellowship-trained surgeons from 1995 to 2021 were included. Patients with supraclavicular brachial plexus injuries, stretch injuries, nonsurgical IBPIs, and brachial plexus dysfunction without traumatic injury were excluded.

Results

The most common cause of injury was motor vehicle accident (74%). Scapular fractures were associated with IBPI in 22% of patients. Isolated branch injuries were the most common (58.8%), of which isolated musculocutaneous nerve injury was the most frequent (40.6%). Preoperative ultrasound and magnetic resonance neurography were concordant with surgical findings in eight of nine and seven of nine patients, respectively. Nerve transfers were the most common intervention (46%). Muscle strength improved after surgery, with an increase from 1 to 5 points on the Medical Research Council scale at 14-50 months after surgery.

Conclusions

Infraclavicular brachial plexus injuries are associated with high-energy trauma and concomitant upper-extremity fractures. Ultrasound and magnetic resonance neurography are mostly concordant with surgical findings in patients undergoing surgical intervention for IBPIs. Prognosis for muscle recovery after surgery is good in patients with IBPIs.

Clinical relevance

Infraclavicular brachial plexus injuries can improve with surgical intervention.

The use of ultrasound-guided imaging to localize peripheral nerve injury in pediatric patients: A case report

Background

The use of ultrasonography to diagnose and manage peripheral nerve injury is not routinely performed, but is an advantageous alternative to magnetic resonance imaging (MRI) in the pediatric population.

Case Description

The authors report a case of a toddler-aged female who sustained a supracondylar fracture and subsequent median and ulnar nerve injuries. All preoperative and postoperative imaging was performed through high-resolution ultrasound as opposed to MRI. Starting at 6 months post-nerve repair and with 18 months of follow-up, the patient exhibited substantial improvement in motor strength and sensory function. This case demonstrated a successful outcome while providing an imaging alternative that is portable, relatively low-cost, lacks ionizing radiation, provides additional information on vascular integrity, and obviates the need for general anesthetic such as MRI.

Conclusion

The authors conclude that the use of ultrasonography to diagnose and manage traumatic peripheral nerve injury is advantageous, particularly in the pediatric population.

Initial findings using high-resolution magnetic resonance imaging for visualisation of the sural nerve and surrounding anatomy in healthy volunteers at 7 Tesla

BACKGROUND AND AIMS

Histopathological diagnosis is the gold standard in many acquired inflammatory, infiltrative and amyloid based peripheral nerve diseases and a sensory nerve biopsy of sural or superficial peroneal nerve is favoured where a biopsy is deemed necessary. The ability to determine nerve pathology by high-resolution imaging techniques resolving anatomy and imaging characteristics might improve diagnosis and obviate the need for biopsy in some. The sural nerve is anatomically variable and occasionally adjacent vessels can be sent for analysis in error. Knowing the exact position and relationships of the nerve prior to surgery could be clinically useful and thus reliably resolving nerve position has some utility.

METHODS

7T images of eight healthy volunteers' (HV) right ankle were acquired in a pilot study using a double-echo in steady-state sequence for high-resolution anatomy images. Magnetic Transfer Ratio images were acquired of the same area. Systematic scoring of the sural, tibial and deep peroneal nerve around the surgical landmark 7 cm from the lateral malleolus was performed (number of fascicles, area in voxels and mm2, diameter and location relative to nearby vessels and muscles).

RESULTS

The sural and tibial nerves were visualised in the high-resolution double-echo in steady-state (DESS) image in all HV. The deep peroneal nerve was not always visualised at level of interest. The MTR values were tightly grouped except in the sural nerve where the nerve was not visualised in two HV. The sural nerve location was found to be variable (e.g., lateral or medial to, or crossing behind, or found positioned directly posterior to the saphenous vein).

INTERPRETATION

High-resolution high-field images have excellent visualisation of the sural nerve and would give surgeons prior knowledge of the position before surgery. Basic imaging characteristics of the sural nerve can be acquired, but more detailed imaging characteristics are not easily evaluable in the very small sural and further developments and specific studies are required for any diagnostic utility at 7T.

Upper Extremity Ballistic Nerve Injury: A Scoping Review and Algorithm for Management

» Gunshot injuries to the upper extremity (UE) have high likelihood for causing peripheral nerve injury secondary to the high density of vital structures. Roughly one-fourth of patients sustaining a gunshot wound (GSW) to the UE incur a nerve injury. Of these nerve injuries, just over half are neurapraxic. In cases of surgical exploration of UE nerve injuries, nearly one-third demonstrate a transected or discontinuous nerve.» Existing literature regarding surgical management of nerve injuries secondary to GSWs comes from both military and civilian injuries. Outcomes are inconsistently reported, and indications are heterogeneous; however, reasonable results can be obtained with nerve reconstruction.» Our proposed management algorithm hinges on 4 treatment questions: if there is a nerve deficit present on examination, if there is a concomitant injury in the extremity (i.e., fracture or vascular insult), whether the injured nerve would be in the operative field of the concomitant injury, and whether there was an identified nerve lesion encountered at the time of surgery by another surgeon?» Early exploration rather than continued expectant management may offer improved recovery from GSW nerve injuries in particular situations. When an UE nerve deficit is present, establishing follow-up after the initial GSW encounter and early referral to a peripheral nerve surgeon are pivotal.

Sciatic nerve fascicle differentiation on high-resolution ultrasound with histological verification: An ex vivo study

INTRODUCTION/AIMS

The development of high-resolution ultrasound (HRUS) has enabled the depiction of peripheral nerve microanatomy in vivo. This study compared HRUS fascicle differentiation to the structural depiction in histological cross-sections (HCS).

METHODS

A human cadaveric sciatic nerve was marked with 10 surgical sutures, and HRUS image acquisition was performed with a 22-MHz probe. The nerve was excised and cut into five segments for HCS preparation. Selected HCS were cross-referenced to HRUS, with sutures to improve orientation. Sciatic nerve and fascicle contouring were performed to assess nerve and fascicular cross-sectional area (CSA), fascicle count, and interfascicular distances. Three groups were defined based on HRUS fascicle differentiation in comparison to HCS, namely single fascicle (SF), fascicular cluster (FC), and no depiction (ND) group.

RESULTS

On cross-referenced HRUS to HCS images, 58% of fascicles were differentiated. On HRUS, significantly larger fascicle CSA and smaller fascicle count were observed compared with HCS. Group analysis showed that 41% of fascicles were defined as SF, 47% as FC, and 12% as ND. The mean fascicle CSA in the ND group was 0.05 mm2. Compared with the SF, the FC had significantly larger fascicle CSA (1.2 ± 0.7 vs. 0.6 ± 0.4 mm2; p < .001) and shorter interfascicular distances (0.1 ± 0.04 vs. 0.5 ± 0.3 μm; p < .001).

DISCUSSION

While HRUS can depict fascicular anatomy, only half of the fascicles visualized on HRUS directly correspond to single fascicles observed on HCS. The amount of interfascicular epineurium appears to influence the ability of HRUS to differentiate individual fascicles.

Nerve Autograft: Preservation of a Lost Art

Nerve autografts involve the transplantation of a segment of the patient's own nerve to bridge a nerve gap. Autografts provide biological compatibility, support for axonal regeneration, and the ability to provide an anatomic scaffold for regrowth that other modalities may not match. Disadvantages of the autograft include donor site morbidity and the extra operative time needed to harvest the graft. Nevertheless, nerve autografts such as the sural nerve remain the gold standard in reconstructing nerve gaps, but a multitude of factors need to be favorable in order to garner reliable, consistent outcomes.

Foot drop in critically ill patients: a narrative review of an elusive complication with intricate implications for recovery and rehabilitation

Foot drop is a condition characterized by the inability to lift the foot upwards towards the shin bone. This condition may affect a proportion of critically ill patients, impacting on their recovery after the acute phase of the illness. The occurrence of foot drop in critical care patients may result from various underlying causes, including neurological injuries, muscular dysfunction, nerve compression, or vascular compromise. Understanding the etiology and assessing the severity of foot drop in these patients is essential for implementing appropriate management strategies and ensuring better patient outcomes. In this comprehensive review, we explore the complexities of foot drop in critically ill patients. We search for the potential risk factors that contribute to its development during critical illness, the impact it has on patients' functional abilities, and the various diagnostic techniques adopted to evaluate its severity. Additionally, we discuss current treatment approaches, rehabilitation strategies, and preventive measures to mitigate the adverse effects of foot drop in the critical care setting. Furthermore, we explore the roles of critical care physical therapists, neurologists, and other healthcare professionals in the comprehensive care of patients with foot drop syndrome and in such highlighting the importance of a multidisciplinary approach.

Ultrasound of Benign Cutaneous Tumors and Pseudotumors: The Key Lesions

Benign cutaneous tumors are commonly seen in daily practice. Most of these lesions are diagnosed based on clinical appearance, but in some cases, clinical findings are nonspecific. A diagnostic imaging exam is indicated to provide additional information, and the first choice for studying dermatologic lesions is a high-frequency color Doppler ultrasound, a noninvasive technique that can play a relevant role in all cases and give important anatomical information for final diagnosis and proper clinical management. This article aims to show the most common benign skin lesions emphasizing clinical-sonographic correlation and familiarizing radiologists with the sonographic appearance of the key benign cutaneous tumors.

Experience with ultrasound neurography for postoperative evaluation of targeted muscle reinnervation

Targeted muscle reinnervation (TMR) was originally developed as a means for increasing intuitive prosthesis control, though later found to play a role in phantom limb pain and neuroma prevention. There is a paucity of literature describing the clinical course of patients with poor TMR surgical outcomes and the value of imaging in the postoperative recovery period. This report will illustrate the potential utility of ultrasound neurography to accurately differentiate TMR surgical outcomes in two patients that received upper extremity amputation and subsequent reconstruction with TMR. Ultrasound evaluation of TMR sites in patient 1 confirmed successful reinnervation, evident by nerve fascicle continuity and eventual integration of the transferred nerve into the target muscle. Conversely, the ultrasound of patient 2 showed discontinuity of the nerve fascicles, neuroma formation, and muscle atrophy in all three sites of nerve transfer, suggesting an unsuccessful procedure and poor functional recovery. Ultrasound neurography is uniquely able to capture the longitudinal trajectory of rerouted nerves to confirm continuity and eventual reinnervation into muscle. Therefore, the application of ultrasound in a postoperative setting can correctly identify instances of failed TMR before this information would become available through clinical evaluation. Early identification of poor TMR outcomes may benefit future patients by fostering the discovery of failure mechanisms and aiding in further surgical planning to improve functional outcomes.

Neuromuscular ultrasound: Impact on diagnosis and management

INTRODUCTION/AIM

High-resolution ultrasound (HRUS) is increasingly used in evaluating neuromuscular conditions. Its potential advantages include its ability to discern anatomic information and make specific etiological diagnoses. Although many studies have demonstrated HRUS effectiveness, especially in mononeuropathies, more information is needed to better determine how often and to what extent useful information is obtained; how it influences diagnosis, clinical decision-making, and patient management; and how it is used with electrodiagnostic (EDx) studies.

METHODS

A retrospective cohort study was performed on patients referred for HRUS at a university laboratory during 2021. Demographic information, referral diagnoses, clinical information, HRUS findings, and follow-up patient management were analyzed. For patients who had EDx, results were compared with HRUS. Determinations were made whether HRUS did or did not aid in the diagnosis. For patients in whom HRUS resulted in a diagnosis, determination was made whether it confirmed the diagnosis made clinically or by EDx but did not change management; added additional important information; and/or made a decisive impact on subsequent management.

RESULTS

Five hundred two patients were analyzed, most referred for mononeuropathy, brachial plexopathy, and polyneuropathy. HRUS was abnormal in 81.7% of patients. HRUS added additional useful information in 79.0% and was decisive in management in 62.7%. In patients who also had abnormal EDx, HRUS resulted in decisive management in 49.5%.

DISCUSSION

HRUS is an effective diagnostic tool that frequently adds localizing and structural information that is otherwise not obtainable by clinical and EDx evaluation. In a substantial number of patients selected for HRUS, it is decisive in guiding further management.

Pronator syndrome and anterior interosseous nerve palsy due to neurolymphomatosis: a case report

Pronator syndrome is a median nerve entrapment neuropathy that can be difficult to diagnose due to its variable presentation and objective findings. Neurolymphomatosis is an uncommon disease in which malignant lymphocytes infiltrate central or peripheral nerve endoneurium and is often missed for prolonged periods prior to diagnosis. We present a rare case of pronator syndrome and anterior interosseous nerve palsy due to neurolymphomatosis that was occult on initial MRI in spite of the presence of a median nerve mass discovered intra-operatively during neurolysis. This case demonstrates the value of ultrasound for the examination of peripheral nerve pathology and illustrates its utility as an adjunct to MRI, in part due to the ability to screen a large region.

Ulnar neuropathy

Ulnar neuropathy at the elbow is the second most common compressive neuropathy. Less common, although similarly disabling, are ulnar neuropathies above the elbow, at the forearm, and the wrist, which can present with different combinations of intrinsic hand muscle weakness and sensory loss. Electrodiagnostic studies are moderately sensitive in diagnosing ulnar neuropathy, although their ability to localize the site of nerve injury is often limited. Nerve imaging with ultrasound can provide greater localization of ulnar injury and identification of specific anatomical pathology causing nerve entrapment. Specifically, imaging can now reliably distinguish ulnar nerve entrapment under the humero-ulnar arcade (cubital tunnel) from nerve injury at the retro-epicondylar groove. Both these pathologies have historically been diagnosed as either "ulnar neuropathy at the elbow," which is non-specific, or "cubital tunnel syndrome," which is often erroneous. Natural history studies are few and limited, although many cases of mild-moderate ulnar neuropathy at the elbow appear to remit spontaneously. Conservative management, perineural steroid injections, and surgical release have all been studied in treating ulnar neuropathy at the elbow. Despite this, questions remain about the most appropriate management for many patients, which is reflected in the absence of management guidelines.

The role of imaging in focal neuropathies

Electrodiagnostic testing (EDX) has been the diagnostic tool of choice in peripheral nerve disease for many years, but in recent years, peripheral nerve imaging has been used ever more frequently in daily clinical practice. Nerve ultrasound and magnetic resonance (MR) neurography are able to visualize nerve structures reliably. These techniques can aid in localizing nerve pathology and can reveal significant anatomical abnormalities underlying nerve pathology that may have been otherwise undetected by EDX. As such, nerve ultrasound and MR neurography can significantly improve diagnostic accuracy and can have a significant effect on treatment strategy. In this chapter, the basic principles and recent developments of these techniques will be discussed, as well as their potential application in several types of peripheral nerve disease, such as carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), radial neuropathy, brachial and lumbosacral plexopathy, neuralgic amyotrophy (NA), fibular, tibial, sciatic, femoral neuropathy, meralgia paresthetica, peripheral nerve trauma, tumors, and inflammatory neuropathies.

[Choosing the right imaging for the diagnostics and assessment of the course of peripheral nerve injuries]

BACKGROUND

Nerve injuries are a frequent problem in routine clinical practice and require intensive interdisciplinary care.

OBJECTIVE

The current status of imaging to confirm the diagnosis of nerve injuries is described. The role of high-resolution ultrasound and magnetic resonance imaging (MRI) in the diagnostics and follow-up of peripheral nerve injuries is elaborated.

MATERIAL AND METHODS

Review of the current state of imaging to confirm the diagnosis of nerve injuries.

RESULTS

Depending on the suspected site of damage, the primary domain of magnetic resonance (MR) imaging (MR neurography) is injuries in the region of the spine, nerve roots, brachial plexus and lumbar plexus, pelvis and proximal thigh. In contrast, in other peripheral nerve lesions of the extremities the advantages of high-resolution nerve ultrasound in a dynamic setting predominate. The MR neurography is indicated here, especially in the frequent bottleneck syndromes and only in very isolated and selected cases.

CONCLUSION

In addition to a correct anatomical assignment, the timely decision for a possible intervention and the appropriate concomitant treatment are an important basis for a favorable prognosis of nerve injuries. Imaging techniques should therefore be used early in the diagnostics and follow-up controls of peripheral nerve injuries.

High-resolution ultrasound and magnetic resonance imaging of ulnar nerve neuropathy in the distal Guyon tunnel

OBJECTIVE

The aim of the present study is to describe the ultrasound (US) and magnetic resonance imaging (MRI) findings in patients with neuropathies affecting the deep (DB) and superficial (SB) branches of the Ulnar nerve (UN) and to investigate the potential role of imaging modalities in the diagnostic workup of these conditions.

MATERIALS AND METHODS

We screened our institutional imaging database to identify patients with a diagnosis of UN mononeuropathy, and among them, we reviewed the cases where US disclosed pathological findings affecting the UN terminal divisions. In this latter subgroup, we retrieved available data on MRI and electrodiagnostic tests performed by the patients during the diagnostic workup. All the patients were evaluated with US machines equipped with 17-5-MHz, 18-4-MHz, 24-8-MHz, or 22-8-MHz probes. MRI exams were performed on a 3-T unit equipped with a 64-channel head RF coil.

RESULTS

Among 166 patients with UN mononeuropathy, we retrieved 15 patients (9%) for which US detected pathological findings affecting the UN terminal divisions, consisting of 7 cases of DB neuropathy, 4 cases of SB neuropathy, and 4 cases of combined neuropathy involving both nerves. Seven (46.7%) patients were submitted to MRI to integrate US findings. Among patients with SB and DB neuropathies, imaging allowed the identification of 7 traumatic nerve injuries, 2 nerve tumors, and 6 entrapment neuropathies, including 4 cases of nerve compression by a ganglion cyst.

CONCLUSION

High-resolution US and MRI are accurate modalities for the investigation of patients with SB/DB neuropathy, can provide critical information on the cause of nerve damage, and guide therapeutic decisions.

CRITICAL RELEVANCE STATEMENT

High-resolution US and MRI are accurate modalities for the investigation of patients with superficial/deep branch of the ulnar nerve neuropathy. In the proper setting, US may be regarded as a first-line approach in patients with suspected neuropathies affecting these small branches.

KEY POINTS

• Neuropathies affecting the distal ulnar nerve often require multimodal investigations. • US and MRI can provide detailed morphological information about the terminal branches of the ulnar nerve. • US may be considered as a first-line approach in suspected distal ulnar nerve neuropathies.

Unveiling the power of imaging techniques: comparing high-resolution ultrasound and functional MR neurography in peripheral nervous system pathology: a short communication

MRI and ultrasonography are used for diagnosing and helping manage peripheral nervous system pathologies. Multiple studies have compared the diagnostic accuracy of these two modalities, but the results can vary depending on the specific conditions being evaluated. In general, high-resolution ultrasound is considered a reliable and accurate tool for evaluating peripheral nerves, with high sensitivity and specificity. High-resolution ultrasound and functional MR neurography are both noninvasive imaging techniques used to evaluate nerve structures in the body. However, they differ in several technical aspects like imaging modality, spatial resolution, field of view, image quality, and accessibility. Establishing consensus on image acquisition techniques, and reporting formats to facilitate effective communication and comparison of results will further enhance the outcomes. The use of advanced ultrasound techniques, such as contrast-enhanced ultrasound, elastography, and ultrasound biomicroscopy, should be promoted for better visualization and characterization of nervous tissues, like transcranial Doppler for cerebrovascular evaluation.

Localization and Diagnostic Evaluation of Peripheral Nerve Disorders

OBJECTIVE

This article provides a framework for the initial evaluation of patients with suspected peripheral nerve disease. The key clinical elements of peripheral nerve diseases can help the practicing neurologist differentiate among peripheral neuropathies with similar presentations.

LATEST DEVELOPMENTS

The wide range of peripheral nerve diseases with similar clinical presentations can pose a diagnostic challenge. The large array of available testing modalities (including imaging and electrodiagnostic, autonomic, laboratory, biopsy, and genetic testing) further complicates clinical decision making. Recent developments (eg, discovery of new autoantibodies, genetic variations, and histopathologic techniques) across the peripheral neuropathy spectrum have resulted in an increased need to evaluate patients logically and with a tailored diagnostic approach.

ESSENTIAL POINTS

A careful approach that focuses on key clinical elements combined with an understanding of purposeful diagnostic testing can lead to a successful diagnosis of peripheral nerve diseases.

Tarsal tunnel ganglion cyst: intraneural or extraneural site?

Intraneural ganglion cysts are very uncommon lesions, whose diagnosis has increased since the articular theory and the description of the MRI findings were established. We present a case report of a 59-year-old man with symptoms of tarsal tunnel syndrome. Foot and ankle MRI demonstrated the presence of an intraneural cystic lesion in the posterior tibial neve and its connection with the subtalar joint through an articular branch. The identification of the specific radiological signs like the «signet ring sign» allowed establishing an adequate preoperative diagnosis, differentiating it from an extraneural lesion and facilitating the articular disconnection of the nerve branch during surgery.

Imaging diagnosis in peripheral nerve injury

Peripheral nerve injuries (PNIs) can be caused by various factors, ranging from penetrating injury to compression, stretch and ischemia, and can result in a range of clinical manifestations. Therapeutic interventions can vary depending on the severity, site, and cause of the injury. Imaging plays a crucial role in the precise orientation and planning of surgical interventions, as well as in monitoring the progression of the injury and evaluating treatment outcomes. PNIs can be categorized based on severity into neurapraxia, axonotmesis, and neurotmesis. While PNIs are more common in upper limbs, the localization of the injured site can be challenging. Currently, a variety of imaging modalities including ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI) and positron emission tomography (PET) have been applied in detection and diagnosis of PNIs, and the imaging efficiency and accuracy many vary based on the nature of injuries and severity. This article provides an overview of the causes, severity, and clinical manifestations of PNIs and highlights the role of imaging in their management.

An unusual cause of posterior interosseous nerve palsy and contribution of ultrasonography to electromyography in a patient with neurofibroma

Neurofibroma, a benign peripheral nerve sheath tumor, represents a rare cause of posterior interosseous nerve syndrome. Electrodiagnostic studies may not identify the exact site of nerve compression, a possible lesion that compresses the nerve and do not provide information about the morphological changes. Ultrasound is a cost-effective, practical modality that provides the opportunity for dynamic tracking in the peripheral nerves, and it is widely considered as the initial imaging modality for peripheral nerves. Herein, we report a case of posterior interosseous nerve palsy in a 13-year-old boy with neurofibroma of posterior interosseous nerve diagnosed with ultrasound. The benefit of ultrasound in localizing and determining the etiology of the posterior interosseous nerve palsy is emphasized in this case report. A meticulous ultrasound examination is recommended in suspected peripheral nerve lesions, regardless of the results of electrophysiological and imaging modalities.

A scoping review of current and emerging techniques for evaluation of peripheral nerve health, degeneration and regeneration: part 2, non-invasive imaging

Peripheral neuroregenerative research and therapeutic options are expanding exponentially. With this expansion comes an increasing need to reliably evaluate and quantify nerve health. Valid and responsive measures of the nerve status are essential for both clinical and research purposes for diagnosis, longitudinal follow-up, and monitoring the impact of any intervention. Furthermore, novel biomarkers can elucidate regenerative mechanisms and open new avenues for research. Without such measures, clinical decision-making is impaired, and research becomes more costly, time-consuming, and sometimes infeasible. Part 1 of this two-part scoping review focused on neurophysiology. In part 2, we identify and critically examine many current and emerging non-invasive imaging techniques that have the potential to evaluate peripheral nerve health, particularly from the perspective of regenerative therapies and research.

Comparison of Magnetic Resonance Imaging and High-Resolution Ultrasound for the Diagnosis of Pathologies of the Peripheral Nerve

The study was done to evaluate high-resolution ultrasound with Magnetic Resonance Imaging (MRI) for the diagnosis of peripheral nerve pathologies. Ultrasound examination and MRI were performed for selected cases, and their sensitivity and specificity were compared. Ultrasound was found to detect peripheral pathologies with greater accuracy as compared to MRI. Also, ultrasound was found to have higher sensitivity and specificity than MRI. It was concluded that ultrasound is a better adjunct tool for the diagnosis of peripheral nerve lesions when compared with MRI.

Ultrasound-Guided Pulsed Radiofrequency Treatment for Superficial Peroneal Nerve Entrapment in a Professional Handball Player

Peripheral nerve injury in athletes is rare but deleterious to their performance, entrapment being one of the most frequent causes. Isolated injury to the superficial peroneal nerve (SPN) is rare and often underdiagnosed. The authors reported a clinical case of a 34-year-old handball athlete who presented with neuropathic pain in the inferolateral third of the leg and dorsum of the foot, with three months of evolution, after an ankle sprain, refractory to conservative treatment. After clinical assessment and ultrasound investigation, it was considered that the pain source was likely to be an SPN entrapment. Thus, a diagnostic ultrasound-guided nerve block with 2ml of 2% lidocaine and 3ml of 0.2% ropivacaine was performed, followed by nerve hydrodissection, with a major improvement in the patient's symptoms and functionality for three weeks. Thereafter, a long-lasting alternative was made - pulsed radiofrequency (pRF). There were no complications after the procedure. As a form of neuromodulation, pRF offered pain resolution without tissue damage or painful sequela, after 3, 6, 12, and 24 months of follow-up and complete participation in sports activity, avoiding surgical treatment. With this clinical case, the authors intend to demonstrate the effectiveness of pRF in the resolution of peripheral neuropathy due to entrapment, avoiding more invasive treatment options and, in the case of an athlete, allowing an early return to play. They also intend to corroborate the advantage of using ultrasound in the diagnosis and guide of minimally invasive procedures.

Ultrasound of peripheral nerve injury

Nerve injury in children is important to recognize early given the greater chance for recovery. Both children and adults have better outcomes the sooner nerve injuries are recognized and repaired. Children have even better functional results after surgical repair, thought to be related to their neural plasticity. Ultrasound is a powerful diagnostic tool for grading and mapping peripheral nerve injury and is complementary to electromyography and nerve conduction studies. Nerve injuries can be classified into low and high grade with ultrasound adding essential prognostic information and aiding in patient management. High-grade nerve injuries likely require surgical intervention. This article will review nerve anatomy and injury grading systems that radiologists can learn quickly in order to accurately communicate with their clinical partners. A practical approach to describe the sonographic appearance of nerve injury will be discussed. This article will show radiologists how the added value of ultrasound for peripheral nerve injury can directly affect clinical management.

Peripheral Nerve Imaging

Magnetic resonance (MR) neurography and high-resolution ultrasound are complementary modalities for imaging peripheral nerves. Advances in imaging technology and optimized techniques allow for detailed assessment of nerve anatomy and nerve pathologic condition. Diagnostic accuracy of imaging modalities likely reflects local expertise and availability of the latest imaging technology.

Traumatic neuromas of peripheral nerves: Diagnosis, management and future perspectives

Traumatic neuromas are infrequent in clinical settings but are prevalent following trauma or surgery. A traumatic neuroma is not a true malignancy, rather, it is a hyperplastic, reparative nerve reaction after injury and typically manifests as a nodular mass. The most common clinical manifestations include painful hypersensitivity and the presence of a trigger point that causes neuralgic pain, which could seriously decrease the living standards of patients. While various studies are conducted aiming to improve current diagnosis and management strategies via the induction of emerging imaging tools and surgical or conservative treatment. However, researchers and clinicians have yet to reach a consensus regarding traumatic neuromas. In this review, we aim to start with the possible underlying mechanisms of traumatic neuromas, elaborate on the diagnosis, treatment, and prevention schemes, and discuss the current experiment models and advances in research for the future management of traumatic neuromas.

Hybrid reflected-ultrasound computed tomography versus B-mode-ultrasound for muscle scoring in spinal muscular atrophy

BACKGROUND AND PURPOSE

Novel light- and sound-based technologies like multispectral optoacoustic tomography (MSOT) with co-registered reflected-ultrasound computed tomography (RUCT) could add additional value to conventional ultrasound (US) for disease phenotyping in pediatric spinal muscular atrophy (SMA). The aim of this study was to investigate the quality of RUCT compared to US for qualitative and quantitative assessment of imaging neuromuscular disorders.

METHODS

Subanalyzing the MSOT SMA study, 288 RUCT and 276 US images from 10 SMA patients (mean age 9.0 ± 3.7) and 10 gender- and age-matched healthy volunteers (HV; mean age 8.7 ± 4.3) were analyzed for quantitative (grayscale levels [GSLs]) and qualitative (echogenicity, distribution pattern, Heckmatt scale, and muscle texture) muscle changes. RUCT and US measures were further correlated with clinical standard motor outcomes.

RESULTS

Quantitative agreement using GSLs revealed significantly higher GSLs in muscles of SMA patients compared to healthy muscles in both techniques (US mean GSL [SD] SMA vs. HV: 110.70 [27.8] vs. 68.85 [19.2], p < .0001; RUCT mean GSL [SD] SMA vs. HV: 91.81 [21.8] vs. 59.86 [8.2], p < .0001) with good correlation with motor outcome tests, respectively. Qualitative agreement between methods for muscle composition was excellent for differentiation of pathological versus healthy muscles, echogenicity, and distribution pattern, moderate for Heckmatt scale, and poor for muscle texture.

CONCLUSIONS

The data suggest that RUCT may allow the assessment of basic qualitative and quantitative measures for muscular diseases with comparable results to conventional US.

Iatrogenic Nerve Injuries of the Upper Extremity: A Critical Analysis Review

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Iatrogenic nerve injuries may occur after any intervention of the upper extremity.

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Causes of iatrogenic nerve lesions include direct sharp or thermal injury, retraction, compression from implants or compartment syndrome, injection, patient positioning, radiation, and cast/splint application, among others.

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Optimal treatment of iatrogenic peripheral nerve lesions relies on early and accurate diagnosis.

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Advanced imaging modalities (e.g., ultrasound and magnetic resonance imaging) and electrodiagnostic studies aid and assist in preoperative planning.

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Optimal treatment of iatrogenic injuries is situation-dependent and depends on the feasibility of direct repair, grafting, and functional transfers.

Electrophysiology and Magnetic Resonance Neurography Findings of Nontraumatic Ulnar Mononeuropathy From a Tertiary Care Center

BACKGROUND

Ulnar nerve is frequently involved in mononeuropathies of the upper limb. Ulnar neuropathies have been diagnosed conventionally using clinical and electrophysiological findings. Physicians opt for nerve imaging in patients with ambiguous electrophysiological tests to gain additional information, identify etiology and plan management.

OBJECTIVES

The aim of this study was to describe the electrophysiological and the magnetic resonance neurography (MRN) findings in patients with nontraumatic ulnar neuropathy.

METHODS

All consecutive patients with suspected nontraumatic ulnar mononeuropathy were recruited; clinical assessment and electrophysiological studies (EPSs) were done in all. After EPS, patients with localization of lesion along the ulnar nerve underwent MRN.

RESULTS

All 39 patients recruited had clinical findings suggestive of ulnar neuropathy; Electrophysiological confirmation was possible in 36/39 (92.30%) patients. Localization of ulnar nerve lesion to elbow and wrist was possible in 27 (75%) and 9 (25%) patients, respectively. MRN was done in 22 patients; a lesion was identified in 19 of 22 (86.36%) ulnar nerves studied. Thickening and hyperintensity in T2 W/short TI inversion recovery images of ulnar nerve at the level of olecranon, suggesting ulnar neuropathy at elbow, was the commonest (8/22) imaging finding.

CONCLUSIONS

MRN acts as a complimentary tool to EPS for evaluating nontraumatic ulnar neuropathy. By identifying the etiology, MRN is likely to modify the management decision.

Morphological and Mechanical Properties of Lower-Limb Muscles in Type 2 Diabetes: New Potential Imaging Indicators for Monitoring the Progress of DPN

The aim of this study was to explore changes in morphological and mechanical properties of lower-limb skeletal muscles in patients with diabetes with and without diabetic peripheral neuropathy (DPN) and seek to find a potential image indicator for monitoring the progress of DPN in patients with type 2 diabetes mellitus (T2DM). A total of 203 patients with T2DM, with and without DPN, were included in this study. Ultrasonography and ultrasound shear wave imaging (USWI) of the abductor hallux (AbH), tibialis anterior (TA), and peroneal longus (PER) muscles were performed for each subject, and the shear wave velocity (SWV) and cross-sectional area (CSA) of each AbH, TA, and PER were measured. The clinical factors influencing AbH_CSA and AbH_SWV were analyzed, and the risk factors for DPN complications were investigated. AbH_CSA and AbH_SWV in the T2DM group with DPN decreased significantly (P < 0.05), but no significant differences were found in the SWV and CSA of the TA and PER between the two groups. Toronto Clinical Scoring System (CSS) score and glycosylated hemoglobin (HbA1c) were independent predictors of AbH_CSA and AbH_SWV. As AbH_SWV and AbH_CSA decreased, Toronto CSS score and HbA1c increased and incidence of DPN increased significantly. In conclusion, the AbH muscle of T2DM patients with DPN became smaller and softer, while its morphological and mechanical properties were associated with the clinical indicators related to the progression of DPN. Thus, they could be potential imaging indicators for monitoring the progress of DPN in T2DM patients.

High resolution ultrasound for the evaluation of radial nerve pathology adjacent to metallic hardware

Accurate localization and characterization of peripheral nerve injuries adjacent to metallic hardware is difficult with magnetic resonance imaging (MRI) due to susceptibility artifact. This study sought to present the use of high-resolution ultrasound (US) in accurate characterization of radial nerve injury adjacent to metallic hardware, using findings at the time of operative exploration as confirmation of the US assessment. A retrospective chart review of cases with clinically identified radial nerve injuries evaluated by the high-resolution US was performed from January 2015 through December 2019. Preoperative clinical data, US reports, MRI reports, electrodiagnostic (EDx) reports, and operative reports were reviewed for each case. Preoperative US correctly characterized the affected nerve component, type, and location of injury in all 13 cases (100%), when correlated with intraoperative findings. Nerve injury was directly adjacent to metallic hardware in 12 cases (92%). Out of the seven cases evaluated by both US and MRI, US correctly accurately diagnosed radial nerve injuries in all cases, whereas MRI accurately diagnosed in four cases (57%). In 3/7 cases (43%) MRI was nondiagnostic due to susceptibility artifact. MRI evaluation of the nerve was limited to some degree by metallic artifact in 6/7 cases (85%).

Peripheral nerve defects repaired with autogenous vein grafts filled with platelet-rich plasma and active nerve microtissues and evaluated by novel multimodal ultrasound techniques

BACKGROUND

Developing biocompatible nerve conduits that accelerate peripheral nerve regeneration, lengthening and functional recovery remains a challenge. The combined application of nerve microtissues and platelet-rich plasma (PRP) provides abundant Schwann cells (SCs) and various natural growth factors and can compensate for the deficiency of SCs in the nerve bridge, as well as the limitations of applying a single type of growth factor. Multimodal ultrasound evaluation can provide additional information on the stiffness and microvascular flow perfusion of the tissue. This study was designed to investigate the effectiveness of a novel tissue-engineered nerve graft composed of an autogenous vein, nerve microtissues and PRP in reconstructing a 12-mm tibial nerve defect and to explore the value of multimodal ultrasound techniques in evaluating the prognosis of nerve repair.

METHODS

In vitro, nerve microtissue activity was first investigated, and the effects on SC proliferation, migration, factor secretion, and axonal regeneration of dorsal root ganglia (DRG) were evaluated by coculture with nerve microtissues and PRP. In vivo, seventy-five rabbits were equally and randomly divided into Hollow, PRP, Micro-T (Microtissues), Micro-T + PRP and Autograft groups. By analysing the neurological function, electrophysiological recovery, and the comparative results of multimodal ultrasound and histological evaluation, we investigated the effect of these new nerve grafts in repairing tibial nerve defects.

RESULTS

Our results showed that the combined application of nerve microtissues and PRP could significantly promote the proliferation, secretion and migration of SCs and the regeneration of axons in the early stage. The Micro-T + PRP group and Autograft groups exhibited the best nerve repair 12 weeks postoperatively. In addition, the changes in target tissue stiffness and microvascular perfusion on multimodal ultrasound (shear wave elastography; contrast-enhanced ultrasonography; Angio PlaneWave UltrasenSitive, AngioPLUS) were significantly correlated with the histological results, such as collagen area percentage and VEGF expression, respectively.

CONCLUSION

Our novel tissue-engineered nerve graft shows excellent efficacy in repairing 12-mm defects of the tibial nerve in rabbits. Moreover, multimodal ultrasound may provide a clinical reference for prognosis by quantitatively evaluating the stiffness and microvescular flow of nerve grafts and targeted muscles.

Imaging of Nerve Disorders in the Elbow

Neuropathies of the elbow represent a spectrum of disorders that involve more frequently the ulnar, radial, and median nerves. Reported multiple pathogenic factors include mechanical compression, trauma, inflammatory conditions, infections, as well as tumor-like and neoplastic processes. A thorough understanding of the anatomy of these peripheral nerves is crucial because clinical symptoms and imaging findings depend on which components of the affected nerve are involved. Correlating clinical history with the imaging manifestations of these disorders requires familiarity across all diagnostic modalities. This understanding allows for a targeted imaging work-up that can lead to a prompt and accurate diagnosis.

Isolated Proximal Median Neuropathy after Aortic Dissection Repair: Case Report

Surgery-related isolated proximal median neuropathy is a rare complication. Brachial plexus injury is a possible complication after major cardiac surgery; however, isolated mononeuropathy is less frequently documented. We present an unusual case of isolated proximal median neuropathy after aortic dissection repair surgery in a 39-year-old man. Electrodiagnostic study and ultrasound examinations helped in localizing the lesion to the axillary region. Serial follow-ups showed improvement in electrodiagnostic parameters, which were compatible with clinical symptoms. Partial recovery was achieved at the seventh month follow-up. This case report aimed to increase awareness of nerve stretching during open heart surgery and demonstrate the diagnosis and clinical follow-up by concomitant use of electrodiagnostic and nerve ultrasound studies.

Respiratory and peripheral muscular ultrasound characteristics in ICU COVID 19 ARDS patients

PURPOSE

Severe cases of coronavirus disease 2019 develop ARDS requiring admission to the ICU. This study aimed to investigate the ultrasound characteristics of respiratory and peripheral muscles of patients affected by COVID19 who require mechanical ventilation.

MATERIALS AND METHODS

This is a prospective observational study. We performed muscle ultrasound at the admission of ICU in 32 intubated patients with ARDS COVID19. The ultrasound was comprehensive of thickness and echogenicity of both parasternal intercostal and diaphragm muscles, and cross-sectional area and echogenicity of the rectus femoris.

RESULTS

Patients who survived showed a significantly lower echogenicity score as compared with those who did not survive for both parasternal intercostal muscles. Similarly, the diaphragmatic echogenicity was significantly different between alive or dead patients. There was a significant correlation between right parasternal intercostal or diaphragm echogenicity and the cumulative fluid balance and urine protein output. Similar results were detected for rectus femoris echogenicity.

CONCLUSIONS

The early changes detected by echogenicity ultrasound suggest a potential benefit of proactive early therapies designed to preserve respiratory and peripheral muscle architecture to reduce days on MV, although what constitutes a clinically significant change in muscle echogenicity remains unknown.