Peripheral nerve lesions: role of high-resolution US

Sonographic Evaluation of the Lateral Femoral Cutaneous Nerve: Single-Institution Experience and Pictorial Review

ABSTRACT

The location of the lateral femoral cutaneous nerve (LFCN) makes it susceptible to injury with trauma, external compression, and iatrogenic injury. The objectives of this study were to report the single-institution efficacy of LFCN visualization on ultrasound (US), define the clinical characteristics of patients with LFCN palsy, and describe sonographic appearances of LFCN abnormalities by pictorial review. A retrospective chart review of LFCN cases evaluated using US at a single institution was performed, documenting rate of visibility on US, mode of nerve injury, and US imaging findings. Nerve visibility rates on US were correlated with magnetic resonance imaging (MRI) when both modalities were used. Imaging findings were confirmed with clinical/surgical history and follow-up. Retrospective review found that 170 patients underwent US for LFCN evaluation in the last 10 years. Injury was associated with surgical intervention in 56% of cases, and perineural scarring was the most common pathology described using US. Lateral femoral cutaneous nerve was visible on US in 97% of cases; MRI visualized LFCN in 60%. Chart review showed US as an effective tool in evaluating LFCN pathology, with a higher visualization rate than MRI. Through pictorial review, the array of LFCN pathology sonographically detectable is demonstrated.

Protect the recurrent laryngeal nerves in US-guided microwave ablation of thyroid nodules at Zuckerkandl tubercle: a pilot study

BACKGROUND

To evaluate the safety and efficacy of US-guided microwave ablation in patients with thyroid nodules at Zuckerkandl tubercle.

METHODS

103 consecutive patients with thyroid nodules at Zuckerkandl tubercle (ZTTN) were enrolled in this study from November 2017 to August 2021. Prior to the surgery or US-guided microwave ablation (MWA), preoperative ultrasound visualization of the recurrent laryngeal nerve (RLN) and ZTTN was performed, the size and the position relationship between them were observed. Patients were followed up at 1, 3, 6, and 12 months after MWA and the volume reduction rates (VRR) of the thyroid nodules were analyzed.

RESULTS

All patients successfully had the RLN and ZTTN detected using ultrasound before surgery or ablation with a detection rate of 100%. For the 103 patients, the majority of ZTTN grades were categorized as grade 2, with the distance from the farthest outside of ZTTN to the outer edge of thyroid ranging between 6.0 and 10.0 mm. The position relationship between ZTTN and RLN was predominantly type A in 98 cases, with type D observed in 5 cases. After MWA, the median nodule volume had significantly decreased from 4.61 (2.34, 8.70) ml to 0.42 (0.15, 1.41) ml and the VRR achieved 84.36 ± 13.87% at 12 months. No nodules regrew throughout the 12-month follow-up period. Of the 11 patients experienced hoarseness due to RLN entrapment before ablation, 7 recovered immediately after separation of the RLN and ZTTN during MWA, 2 recovered after one week, and the other 2 recovered after two months.

CONCLUSIONS

The RLN is closely related to ZTTN and mainly located at the back of ZTTN. The RLN can be separated from ZTTN by hydrodissection during MWA. US-guided MWA is a safe and effective treatment for ZTTN.

An Unusual Case of a Giant Schwannoma of the Sciatic Nerve: A Case Report With a Review of Literature

Sciatic nerve schwannomas are rare tumors, mainly characterized by sciatic neuralgia rather than sensory-motor deficits. The poorly suggestive clinical presentation of this localization leads to a delayed diagnosis. Here, we describe the case of a 47-year-old female patient with a nine-month history of schwannoma localized in the sciatic nerve, just above the left popliteal fossa. Although magnetic resonance imaging (MRI) is the imaging modality of choice, the final diagnosis rests on the histological examination of the tumor. The schwannoma must be surgically removed without severing the nerve trunk.

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.

Preventive Effect of Local Lidocaine Administration on the Formation of Traumatic Neuroma

BACKGROUND

Traumatic neuroma is a common sequela of peripheral nerve injury or amputation, which often leads to severe neuropathic pain. The present study investigated the effect of local lidocaine administration on preventing the formation of traumatic neuroma.

METHODS

Forty-eight male Sprague-Dawley rats were randomly assigned to two groups. The lidocaine group underwent sciatic nerve transection, followed by an injection of lidocaine (0.5%) around the proximal of a severed sciatic nerve under ultrasound-guidance 2-7 days after neurectomy. In the control group, rats received an injection of saline following neurectomy. The autotomy score, mechanical allodynia, thermal hyperalgesia, histological assessment, expression of neuroma, and pain-related markers were detected.

RESULTS

Lidocaine treatment reduced the autotomy score and attenuated mechanical allodynia and thermal hyperalgesia. The mRNA expression of α-SMA, NGF, TNF-α, and IL-1β all significantly decreased in the lidocaine group in comparison to those in the saline control group. The histological results showed nerve fibers, demyelination, and collagen hyperplasia in the proximal nerve stump in the saline control group, which were significantly inhibited in the lidocaine group.

CONCLUSIONS

The present study demonstrated that local lidocaine administration could inhibit the formation of painful neuroma due to traumatic nerve injury.

Saphenous Nerve Schwannoma: A Rare Differential Diagnosis of Knee Pain in Children

Schwannomas are uncommon benign tumors of the peripheral nerves with a low risk of malignant transformation. They rarely affect children, can affect any part of the body but rarely occur in the lower extremity and typically present with a palpable mass, pain or neurological signs. Imaging helps to orient the diagnosis and anatomopathological examination helps to confirm it. We report a case of a 12-year-old girl who presented with left knee pain with subcutaneous mass overlying the tibial tuberosity medially. Clinical examination revealed a positive Tinel's sign. Magnetic resonance imaging (MRI) of the knee was performed, which revealed an encapsulated subcutaneous soft tissue mass overlying the tibial tuberosity medially, eccentric to the course of the infrapatellar branch of the saphenous nerve. The patient was operated with total intracapsular excision of the lesion and the anatomopathological study of the surgical specimen came back in favor of a schwannoma. Postoperatively, the patient showed a good recovery with disappearance of pain and swelling.

Investigation of Ultrasound Parameters for the Differential Diagnosis of Malignant and Benign Peripheral Nerve Sheath Tumors

OBJECTIVES

The objectives were to identify the key features of malignant and benign peripheral nerve sheath tumors (PNSTs) and determine a strategy for differentiating them using sonography.

METHODS

Forty-six malignant peripheral nerve sheath tumors (MPNSTs) and 83 benign peripheral nerve sheath tumors (BPNSTs) confirmed by pathology from April 2010 to July 2021 were included. The general data and grayscale and color Doppler ultrasonic manifestations were compared between the two groups. We used single factor, multifactor, and area under the receiver operating characteristic (ROC) curve analyses to extract significant malignant risk factors and then established a scoring system with these factors.

RESULTS

The significant variables identified in univariate analysis (P < .05) were maximum diameter, location, shape, boundary, encapsulation, echogenicity, texture pattern, calcification, entering or exiting nerve, and vascularity. Shape, boundary and vascularity were significant risk factors, and a scoring system was established. The area under the ROC curve (0.925) confirmed the usefulness of the scoring system for differentiating MPNSTs and BPNSTs.

CONCLUSIONS

Ultrasonography is an effective method for differentiating MPNSTs from BPNSTs.

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.

Ultrasonography of Superficial Soft-Tissue Masses: Society of Radiologists in Ultrasound Consensus Conference Statement

The Society of Radiologists in Ultrasound convened a panel of specialists from radiology, orthopedic surgery, and pathology to arrive at a consensus regarding the management of superficial soft-tissue masses imaged with US. The recommendations in this statement are based on analysis of current literature and common practice strategies. This statement reviews and illustrates the US features of common superficial soft-tissue lesions that may manifest as a soft-tissue mass and suggests guidelines for subsequent management.

The EFSUMB Guidelines and Recommendations for Musculoskeletal Ultrasound - Part I: Extraarticular Pathologies

The first part of the guidelines and recommendations for musculoskeletal ultrasound, produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), provides information about the use of musculoskeletal ultrasound for assessing extraarticular structures (muscles, tendons, entheses, ligaments, bones, bursae, fasciae, nerves, skin, subcutaneous tissues, and nails) and their pathologies. Clinical applications, practical points, limitations, and artifacts are described and discussed for every structure. After an extensive literature review, the recommendations have been developed according to the Oxford Centre for Evidence-based Medicine and GRADE criteria and the consensus level was established through a Delphi process. The document is intended to guide clinical users in their daily practice.

The role of ultrasonography in diagnosing hourglass-like fascicular constriction(s) of the anterior interosseous nerve

BACKGROUND

In the past, the diagnosis of hourglass-like fascicular constriction(s) of the anterior interosseous nerve mostly depended on electrophysiological examination, by which the location could not be diagnosed. There are few studies on the evaluation of hourglass-like fascicular constriction(s) by ultrasonography.

PURPOSE

To evaluate the role of ultrasonography in the diagnosis of hourglass-like fascicular constriction(s) of the anterior interosseous nerve.

MATERIAL AND METHODS

A retrospective analysis of 12 patients with hourglass-like fascicular constriction(s) of the anterior interosseous nerve was carried out, and the characteristics of the high-frequency ultrasonographic images were summarized and compared with surgical exploration.

RESULTS

The 12 cases of hourglass-like fascicular constriction(s) of the anterior interosseous nerve were all located in the median nerve of the distal upper arm, including nine cases of single hourglass-like fascicular constriction and three cases of multiple hourglass-like fascicular constrictions. High-frequency ultrasonography can accurately locate the hourglass-like fascicular constriction(s) of the anterior interosseous nerve and the extent of neuropathy. The ultrasonographic images of hourglass-like fascicular constriction(s) of the anterior interosseous nerve showed single or multiple hourglass-like change(s) in the median nerve of the distal upper arm. The nerve fascicles on both sides of the affected nerve with hourglass-like change thickened.

CONCLUSIONS

High-frequency ultrasonography could be a reliable, convenient, and non-invasive diagnostic imaging method for hourglass-like fascicular constriction(s) of the anterior interosseous nerve.

[Schwannoma of the sciatic nerve: a case report]

Les schwannomes du nerf sciatique sont des tumeurs rares. Elles se manifestent essentiellement par des névralgies sciatiques plutôt que par des déficits sensitivo-moteurs. Nous rapportons le cas d´une patiente de 30 ans présentant une douleur de la fesse droite depuis 1 an. La palpation a révélé un signe de Tinel positif. Une imagerie par résonnance magnétique (IRM) a été réalisée qui a objectivé une masse grossièrement arrondie, régulière de 2 cm de diamètre en contact intime avec le nerf grand sciatique. Une exérèse complète de la tumeur a été réalisée. Cette exérèse a permis la disparition de la douleur et l´examen anatomopathologique a conclu à un schwannome plexiforme.

Ultrasonography of the Peripheral Nerves of the Forearm, Wrist and Hand: Definition of Landmarks, Anatomical Correlation and Clinical Implications

BACKGROUND

 Peripheral nerve pathologies of the upper extremity are increasingly assessed by high-resolution ultrasonography (HRUS), yet rapid identification of nerve segments can be difficult due to small nerve diameters and complex regional anatomy. We propose a landmark-based approach to speed up and facilitate evaluation and intervention in this region.

METHOD

 Relevant landmarks and section planes for eleven nerve segments of the forearm, wrist and hand were defined by ultrasonography in cadaver arms before cryosection and topographical neurovascular preparation. Information on all nerve segments and a pictorial guide including anatomical cross-sections, topographical preparations and HRUS images are provided. The identification rates of these nerve segments were then assessed in 20 healthy volunteers.

RESULTS AND CONCLUSION

 Sonographic landmarks and guidelines for the rapid identification and assessment of nerves of the forearm, wrist and hand are presented in pictorial and tabular form, including discussion of normal variants. Utilizing this overview should facilitate training, diagnostic examinations and intervention for nerves of the upper extremity.

KEY POINTS

  · High-resolution ultrasound enables assessment of peripheral nerves of the forearm, wrist and hand.. · A landmark-based approach can facilitate and speed up nerve evaluation in these regions.. · High detection rates could be reproduced using the proposed landmark-based approach..

CITATION FORMAT

· Gruber L, Loizides A, Peer S et al. Ultrasonography of the Peripheral Nerves of the Forearm, Wrist and Hand: Definition of Landmarks, Anatomical Correlation and Clinical Implications. Fortschr Röntgenstr 2020; 192: 1060 - 1072.

Feasibility and Reliability of an Ultrasound Examination to Diagnose Piriformis Syndrome

OBJECTIVE

We explored the diagnostic performance of ultrasound examinations in the diagnosis of piriformis syndrome (PS).

METHODS

In our single-center retrospective study, 52 patients with a diagnosis of PS and 50 healthy volunteers were enrolled to undergo ultrasound examination of the piriformis and sciatic nerve. The thicknesses of the piriformis and the diameter of the sciatic nerve were measured to compare the differences between the patients with PS and healthy volunteers. The diagnostic performance of ultrasound examinations was assessed by constructing a receiver operating characteristic curve and calculating the area under the curve.

RESULTS

In patients with PS, the piriformis and sciatic nerve were enlarged on the abnormal side compared with the asymptomatic side, accompanied by a decreased echo intensity and an unclear perineurium. In addition, the piriformis thickness and sciatic nerve diameter of those with PS were significantly greater than were those of the healthy volunteers. The diagnostic performance of ultrasonography was significant. The area under the receiver operating characteristic curve for piriformis thickness and sciatic nerve diameter to discriminate between the abnormal and asymptomatic sides was 0.778 and 0.871, respectively.

CONCLUSION

Ultrasound examinations can assist in the clinical diagnosis of PS and have the potential to be an alternative method for the diagnosis of PS for most musculoskeletal clinicians.

Quantifying regeneration in patients following peripheral nerve injury

Healthy nerve function provides humans with the control of movement; sensation (such as pain, touch and temperature) and the quality of skin, hair and nails. Injury to this complex system creates a deficit in function, which is slow to recover, and rarely, if ever, returns to what patients consider to be normal. Despite promising results in pre-clinical animal experimentation effective translation is challenged by a current inability to quantify nerve regeneration in human subjects and relate this to measurable and responsible clinical outcomes. In animal models, muscle and nerve tissue samples can be harvested following experimental intervention. This allows direct quantification of muscle mass and quality and quantity of regeneration of axons; such an approach is not applicable in human medicine as it would ensure a significant functional deficit. Nevertheless a greater understanding of this process would allow the relationship that exists between neural and neuromuscular regeneration and functional outcome to be more clearly understood. This article presents a combined commentary of current practice from a specialist clinical unit and research team with regard to laboratory and clinical quantification of nerve regeneration. We highlight how electrophysiological diagnostic methods (which are used with significant recognised limitations in the assessment of clinical medicine) can potentially be used with more validity to interpret and assess the processes of neural regeneration in the clinical context, thus throwing light on the factors at play in translating lab advances into the clinic.

Ultra-high-frequency Ultrasound to Assess Nerve Fascicles in Median Nerve Traumatic Neuroma

A traumatic neuroma is a major cause of persistent neuropathic pain. Diagnostic imaging tools are critical to the success of surgical treatment. Ultra-high-frequency ultrasound is a novel technology that can generate frequencies up to 70 MHz, assessing structures up to 30 μm. We report a unique case of intraoperative use of ultra-high-frequency ultrasound to provide detailed imaging of nerve fascicles, facilitating surgical excision of the mass.

Estimating the most accurate sonographic measurement in the diagnosis of carpal tunnel syndrome: Which is the best?

Objectives

This study aims to identify the most accurate method or ultrasonographic measurement for the diagnosis of carpal tunnel syndrome (CTS).

Patients and methods

Between October 2010 and April 2011, a total of 160 hands of 87 patients (4 males, 83 females; mean age 54.5 years; range, 26 to 84 years) with clinically and electrodiagnostically proven CTS and 80 hands of 40 controls (3 males, 37 females; mean age 53.7 years; range, 32 to 77 years) were evaluated by sonographic examination. The diameters and cross-sectional areas (CSA) of the median nerve and longitudinal diameters of the median nerve were measured at the inlet, proximal carpal tunnel, and outlet of the carpal tunnel. Volar bulging and thickness of the retinaculum were also measured.

Results

The most optimal combination for the diagnosis of CTS was proximal CSA, volar bulging, and the proximal transverse diameter. The combination of proximal CSA with volar bulging increased the sensitivity and specificity of sonographic measurements.

Conclusion

Based on our study results, ultrasonography can be used as a practical modality to distinguish CTS patients from asymptomatic controls.

[Sonographic characteristics of non-traumatic focal hourglass-like nerve constriction]

AIM

To describe the sonographic phenomenon of the focal 'hourglass-like constriction' of the peripheral nerves (FCPN).

MATERIAL AND METHODS

The authors described 7 patients meeting the criteria for the diagnosis of neuralgic amyotrophy with unilateral FCPN identified with ultrasound in 4 cases and detected intraoperatively in 3 cases (preliminary ultrasound was not performed). The US scanner Sonoscape Pro mode gray scale in the transverse and longitudinal scanning, linear probe 8-15 MHz and Logiq9 scanner with elastography were used.

RESULTS

FCPN was detected in the single nerve in 4 patients, in two nerves in 2 patients and in 3 nerves in one patient. Among all the nerves involved in the pathological process, the radial nerve and its branches were affected in 73% (8 nerves); the ulnar nerve was involved in 18% (2 nerves) and the musculo-cutaneous nerve in 9%. The length of the constriction of the peripheral nerve did not exceed 1.7 mm. The deformation coefficient (DC) of constriction area was 3.8 to .,9; the change in the elasticity in the form of an increase of DC to 5.9 when compared to the intact portion of the nerve and a decrease in echogenicity were observed in one patient.

CONCLUSION

High-resolution ultrasound of the nerve can be an informative method for the diagnosis of idiopathic non-traumatic FCPN mononeuropathy.

Ultrasonographic Reference Values for Assessing Normal Sciatic Nerve Ultrasonography in the Normal Population

Objective:

High-resolution ultrasonography (HRUS) has been used recently to characterize median and ulnar nerves but is seldom used to characterize the lower extremity nerves. The reference standard for normal the lower extremity nerves has not been established. Thus, this study measured the cross-sectional areas (CSAs) of the sciatic nerve of 200 healthy male or female volunteers, aged 18–80 using HRUS. These data provide basic clinical data for the use of high-resolution ultrasound for the future diagnosis, treatment, and prognostic evaluation of peripheral neuropathies.

Methods:

Two hundred healthy volunteers with 400 lower extremities were studied with HRUS. According to their age, the subjects were assigned to young group (18-30 years, n = 75), middle group. (31-60 years, n = 70), and old group(61-80 year, n = 55). Age, sex, height, weight were recorded and CSAs of sciatic nerve were obtained at every predetermined sites.

Results:

The mean CSAs of sciatic nerves at GS and MGPF were 0.527 ± 0.028 cm² and 0.444 ± 0.026 cm² respectively. Pearson's correlation analysis showed that the mean CSAs were correlated with height and weight. There was no difference in mean CSAs among the three groups (P > 0.05). Women had smaller CSAs of the normal Sciatic nerves than men in two measuring sites (GS, MGPF) (P < 0.05).

Conclusion:

Peripheral nerve ultrasonography is a reliable and reproducible diagnostic method in the hands of experienced examiners. Normal values for the sciatic nerve nerves are provided by our study. Thus, reference values of Sciatic nerve CSA of the lower extremity can facilitate the analysis of abnormal nerve conditions.

[Ultrasound-guided interventions on the peripheral nervous system]

CLINICAL/METHODICAL ISSUE

Up to the advent of high-resolution ultrasound, interventions on the peripheral nervous system, including local anesthesia and pain treatment were performed without visual guidance, which in some cases led to treatment failure or local tissue and nerve damage.

METHODICAL INNOVATIONS

Progress in the field of ultrasound has enabled the functional visualization, anesthesia and anti-inflammatory or neurolytic treatment of many peripheral nerves, such as the brachial plexus, nerves of the upper and lower extremities and various nerves of the trunk. Contrast medium-guided biopsies have also become feasible.

ACHIEVEMENTS

This article discusses the general prerequisites for such interventions and details the visualization and the interventional algorithms for interventions on the brachial plexus, on large nerves often affected by compression neuropathies, such as the median, ulnar, sciatic and femoral nerves and small nerves, such as the lateral cutaneous nerves of the thigh. Furthermore, contrast medium-aided biopsies of intraneural and perineural masses are discussed. Finally, the treatment of stump neuromas via phenol instillation is described.

PRACTICAL RECOMMENDATIONS

Innovations in high-resolution ultrasound allow the reliable and safe diagnosis and treatment of various pathologies of the peripheral nervous system with few side effects. Compared to older methods, which did not use visual guidance ultrasound provides higher success rates and lower adverse event rates in many instances.

Ultrasound evaluation in traumatic peripheral nerve lesions: from diagnosis to surgical planning and follow-up

Surgical treatment of traumatic nerve lesions is a matter of debate, mostly about the timing and technical aspects of the procedure. In deciding about and planning the operation, it is often necessary to repeat the electrophysiological and neuroradiological studies several times. Here we present our experience with ultrasonography taken before and after surgery: this simple and handy tool allowed clear visualization of the preoperative anatomy, thorough preparation and fast carrying out of surgery, and accurate postoperative monitoring of the graft's vitality at follow-up. Though this is a limited series, the importance of ultrasonographic evaluation in traumatic peripheral nerve lesions appears remarkable.

Intraoperative ultrasound-assisted peripheral nerve surgery

Historically, peripheral nerve surgery has relied on landmarks and fairly extensive dissection for localization of both normal and pathological anatomy. High-resolution ultrasonography is a radiation-free imaging modality that can be used to directly visualize peripheral nerves and their associated pathologies prior to making an incision. It therefore helps in localization of normal and pathological anatomy, which can minimize the need for extensive exposures. The authors found intraoperative ultrasound (US) to be most useful in the management of peripheral nerve tumors and neuromas of nerve branches that are particularly small or have a deep location. This study presents the use of intraoperative US in 5 cases in an effort to illustrate some of the applications of this useful surgical adjunct.

The utility of ultrasound in the assessment of traumatic peripheral nerve lesions: report of 4 cases

Ultrasound technology continues to improve with better image resolution and availability. Its use in evaluating peripheral nerve lesions is increasing. The current review focuses on the utility of ultrasound in traumatic injuries. In this report, the authors present 4 illustrative cases in which high-resolution ultrasound dramatically enhanced the anatomical understanding and surgical planning of traumatic peripheral nerve lesions. Cases include a lacerating injury of the sciatic nerve at the popliteal fossa, a femoral nerve injury from a pseudoaneurysm, an ulnar nerve neuroma after attempted repair with a conduit, and, finally, a spinal accessory nerve injury after biopsy of a supraclavicular fossa lesion. Preoperative ultrasound images and intraoperative pictures are presented with a focus on how ultrasound aided with surgical decision making. These cases are set into context with a review of the literature on peripheral nerve ultrasound and a comparison between ultrasound and MRI modalities.

Ultrasonography-Based Thyroidal and Perithyroidal Anatomy and Its Clinical Significance

Ultrasonography (US)-guided procedures such as ethanol ablation, radiofrequency ablation, laser ablation, selective nerve block, and core needle biopsy have been widely applied in the diagnosis and management of thyroid and neck lesions. For a safe and effective US-guided procedure, knowledge of neck anatomy, particularly that of the nerves, vessels, and other critical structures, is essential. However, most previous reports evaluated neck anatomy based on cadavers, computed tomography, or magnetic resonance imaging rather than US. Therefore, the aim of this article was to elucidate US-based thyroidal and perithyroidal anatomy, as well as its clinical significance in the use of prevention techniques for complications during the US-guided procedures. Knowledge of these areas may be helpful for maximizing the efficacy and minimizing the complications of US-guided procedures for the thyroid and other neck lesions.

Cross-sectional sonographic assessment of the posterior interosseous nerve

PURPOSE

Cross-sectional sonographic measurements are considered first-line confirmatory tests in diagnosing peripheral nerve entrapment syndromes. Our aim is to establish normal values of cross-sectional area of the posterior interosseous nerve (PIN) at the arcade of Frohse, the most common site of compression of this nerve.

METHODS

The PIN was identified with ultrasound on 50 healthy adults and 30 cadavers. Measurements of the cross-sectional area (CSA), antero-posterior (AP) and lateral (L) distances were taken immediately proximal and distal to the arcade of Frohse.

RESULTS

The mean AP and L distances of the PIN proximal to the arcade of Frohse were 0.111 cm (0 ± 0.021) and 0.266 cm (±0.058), respectively, while the mean AP and L distances of the PIN distal to the arcade of Frohse were 0.085 cm (±0.019) and 0.343 cm (±0.057), respectively. P squared testing showed a statistically significant difference between the AP and lateral distances of the PIN when comparing proximal and distal to the arcade (p ≤ 0.001). However, the mean CSA of the PIN measured immediately proximal to the arcade of Frohse was 0.022 cm(2) (±0.005); immediately distal to the arcade of Frohse, it was 0.023 cm(2) (±0.004). t test showed no statistical difference between the two regions (p = 0.11).

CONCLUSIONS

Our study has provided reference values for the PIN in healthy individuals at the arcade of Frohse. Although, there is a flattening of the nerve as it enters the supinator muscle, this should not be mistaken for nerve entrapment as the size of the nerve remains consistent.

In-continuity neuroma of the median nerve after surgical release for carpal tunnel syndrome: case report

Iatrogenic injuries of the median nerve after surgical release for carpal tunnel syndrome resulting in the formation of a neuroma are rare. We present here the case of two patients, one with a bifid median nerve, showing in-continuity neuroma after surgical release for carpal tunnel syndrome. The patients reported persistent post-operative pain and showing symptoms. In both cases, ultrasound showed an in-continuity neuroma with a hypoechoic and enlarged median nerve at the carpal tunnel. The case report shows that ultrasound may be helpful in confirming the clinical diagnosis of neuroma and it is useful for evaluation of the percentage of the area affected by the tear.

In-continuity neuroma of the median nerve at the elbow

Neuromas are a hyperplastic disorganised proliferation of cells that represent an attempt at nerve regeneration after trauma. They can be classified into terminal and in-continuity neuromas; the latter are observed when the nerve stumps are both connected. We present here the case of a 46-year-old male who sustained a deep cut at the volar aspect of the right elbow while repairing a glass. The injury caused partial transection of the median nerve, which was initially unrecognised. After several months, the patient presented pain at the volar aspect of the elbow, worsening with manual compression at the site of previous injury. Ultrasound showed an in-continuity neuroma with a hypoechoic and enlarged median nerve at the site of the sutured wound. The case report shows that ultrasound may be helpful in confirming the clinical diagnosis of neuroma and that it is useful to evaluate the percentage of the area affected by the lesion.

High resolution ultrasound in the evaluation and management of traumatic peripheral nerve injuries: review of the literature

High-resolution ultrasound has been used as an important tool in the diagnosis, management and monitoring of both acute and chronic peripheral nerve injuries. According to literature, it demonstrated high sensitivity and specificity for the detection of specific pathologies and its ability to differentiate between them. Literature has been reviewed, summarizing the specific finding of such modality in various peripheral neuropathies and with a specific focus over its role in evaluation and management of traumatic peripheral neuropathies.

An analysis of contrast agent flow patterns from sequential ultrasound images using a motion estimation algorithm based on optical flow patterns

This study estimates flow patterns of contrast agents from successive ultrasound image sequences by using an anisotropic diffusion-based optical flow algorithm. Before flow fields were recovered, the test sequences were reconstructed using relative composition of structural and textural parts from the original image. To improve estimation performance, an anisotropic diffusion filtering model was embedded into a spline-based slightly nonconvex total variation-L1 minimization algorithm. In addition, an incremental coarse-to-fine warping framework was employed with a linear minimization scheme to account for a large displacement. After each warping iteration, the implementation used intermediate bilateral filtering to prevent oversmoothing across motion boundaries. The performance of the proposed algorithm was tested using three different sequences obtained from two simulated datasets and phantom ultrasound sequences. The results indicate the robust performance of the proposed method under different noise environments. The results of the phantom study also demonstrate reliable performance according to different injection conditions of contrast agents. These experimental results suggest the potential clinical applicability of the proposed algorithm to ultrasonographic diagnosis based on contrast agents.

High-resolution ultrasonography for the diagnosis of brachial plexus root lesions

The aim of this study was to investigate the feasibility of using high-resolution ultrasonography in the diagnosis of brachial plexus (BP) root lesions. A prospective study of ultrasonographic evaluation of BP nerve roots was performed in 37 patients with BP root lesions (29 with root injuries, 8 with tumors). The pre-operative ultrasonographic findings were compared with the surgical and pathohistological findings. All C5-7 roots were detected by ultrasonography in all patients, whereas 92% (68/74) of C8 and 51% (38/74) of T1 nerve roots were visualized. Among 29 patients with BP root avulsion, partial injuries or totally interrupted BP roots were detected in all patients. Cystic masses and neuromas were detected in 16 and 23 patients, respectively. In 8 patients with BP root tumors, 8 hypo-echoic masses were detected inside or partly outside of intervertebral foramina connecting to nerve roots. Surgical exploration revealed that there were 57 BP root avulsions in 29 patients. However, 2 T1 nerve root avulsions had been missed by pre-operative ultrasonography. Pathohistology revealed that all 8 BP root tumors pre-operatively diagnosed by ultrasonography were schwannomas. High-resolution ultrasonography can provide a convenient and accurate imaging modality for quick diagnosis and location of BP root lesions.

Ultrasound and neurophysiological correlation in common fibular nerve conduction block at fibular head

OBJECTIVE

Ultrasound (US) and neurophysiological examination are useful tools in the evaluation of common fibular mononeuropathy. There is only a report comparing US and electrophysiological parameters in patients with common fibular nerve (CFN) conduction block at fibular head. We investigated the correlation between US and neurophysiologic findings in this condition.

METHODS

We retrospectively reviewed patients with CFN assessed in our lab during last 2 years. Each patient underwent to clinical, neurophysiological and ultrasound evaluations. Cross sectional area (CSA) of CFN at fibular head was assessed.

RESULTS

Twenty-four patients were included. Motor nerve conduction study showed a reduction of distal compound muscle action potential (CMAP) amplitude in 10 patients (mean 1.3 mV). US showed an increased CSA in 10 patients. Statistical analysis revealed a strong correlation between the increased CSA and the CMAP reduction of CFN.

CONCLUSION

Our data suggest that usually US examination is normal in CFN conduction block at fibular head. However the association with axonal damage is frequently accompanied by an increase of CSA.

SIGNIFICANCE

Ultrasound evaluation may represent a powerful diagnostic/prognostic tool in cases with CPN conduction block at fibular head because it usually shows normal pattern in pure conduction block and increase of CSA in associated axonal damage.

Comprehensive musculoskeletal sonographic evaluation of the hand and wrist

Sonography is widely used for evaluation of hand and wrist lesions. The easy accessibility, cost-effectiveness, and good diagnostic accuracy of sonography coupled with the numerous benefits of real-time imaging make it desirable. The aim of this article is to describe the typical sonographic appearances of lesions in the hand and wrist that are encountered frequently in routine clinical practice, such as inflammatory arthropathies, tumors, traumatic injuries, foreign bodies, and nerve entrapment syndromes. Relevant anatomy, scanning methods, and recent developments in musculoskeletal sonography are also discussed.

Ultrasonography- or electrophysiology-guided suprascapular nerve block in arthroscopic acromioplasty: a prospective, double-blind, parallel-group, randomized controlled study of efficacy

PURPOSE

To evaluate the efficacy of ultrasonography-guided (UG) and electrophysiology-guided (EG) suprascapular nerve block (SNB) for arthroscopic acromioplasty with regard to pain relief.

METHODS

A prospective, double-blind, randomized controlled clinical trial was performed from June 2007 to April 2010. Patients who were scheduled for elective arthroscopic acromioplasty and who met the inclusion criteria were assigned to 1 of 2 experimental groups (UG or EG SNB) or to 1 blind group (using anatomic landmarks). Before surgery, an SNB was performed with either ultrasonographic or electrophysiologic guidance or with no assistive devices (blind). Variables were collected at 4, 24, 48, and 72 hours postoperatively.

RESULTS

Sixty-three patients were initially enrolled in the study, but 11 dropped out for various reasons. In the UG group at 4 hours, the visual analog scale score at rest (30 ± 12.0 v 39 ± 9.9 for EG group and 41 ± 11.8 for blind group) and when the patient was moving (42 ± 15.2 v 52 ± 11.5 for EG group and 53 ± 12.6 for blind group) was significantly decreased compared with the EG and blind groups (P < .05). Opioid consumption during the first 24 hours was significantly reduced in the UG and EG groups (4.3 ± 1.9 mg and 3.8 ± 2.3 mg, respectively) compared with the blind group (5.1 ± 2.2 mg) (P < .05). The visual analog scale score at rest and when the patient was moving; the pain score on the University of California, Los Angeles questionnaire; and the activities of daily living score on the American Shoulder and Elbow Surgeons questionnaire in the EG and UG groups improved more than the values in the blind group over the follow-up intervals (P < .05). Morphine consumption in the EG and UG groups by the first, second, and third days was significantly smaller than that in the blind control group (P < .05).

CONCLUSIONS

UG and EG SNB can reduce pain and painkiller consumption for up to 72 hours postoperatively. Ultrasonographic or electrophysiologic guidance is more effective than the blind method of SNB.

LEVEL OF EVIDENCE

Level I, randomized controlled trial with significant difference.

Detection of peripheral nerve pathology: comparison of ultrasound and MRI

OBJECTIVE

To compare accuracy of ultrasound and MRI for detecting focal peripheral nerve pathology, excluding idiopathic carpal or cubital tunnel syndromes.

METHODS

We performed a retrospective review of patients referred for neuromuscular ultrasound to identify patients who had ultrasound and MRI of the same limb for suspected brachial plexopathy or mononeuropathies, excluding carpal/cubital tunnel syndromes. Ultrasound and MRI results were compared to diagnoses determined by surgical or, if not performed, clinical/electrodiagnostic evaluation.

RESULTS

We identified 53 patients who had both ultrasound and MRI of whom 46 (87%) had nerve pathology diagnosed by surgical (n = 39) or clinical/electrodiagnostic (n = 14) evaluation. Ultrasound detected the diagnosed nerve pathology (true positive) more often than MRI (43/46 vs 31/46, p < 0.001). Nerve pathology was correctly excluded (true negative) with equal frequency by MRI and ultrasound (both 6/7). In 25% (13/53), ultrasound was accurate (true positive or true negative) when MRI was not. These pathologies were typically (10/13) long (>2 cm) and only occasionally (2/13) outside the MRI field of view. MRI missed multifocal pathology identified with ultrasound in 6 of 7 patients, often (5/7) because pathology was outside the MRI field of view.

CONCLUSIONS

Imaging frequently detects peripheral nerve pathology and contributes to the differential diagnosis in patients with mononeuropathies and brachial plexopathies. Ultrasound is more sensitive than MRI (93% vs 67%), has equivalent specificity (86%), and better identifies multifocal lesions than MRI. In sonographically accessible regions ultrasound is the preferred initial imaging modality for anatomic evaluation of suspected peripheral nervous system lesions.