Ultrasound-guided treatment of meralgia paresthetica (lateral femoral cutaneous neuropathy): technical description and results of treatment in 20 consecutive patients

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.

Ultrasound-guided Musculoskeletal Interventional Procedures Around the Hip: A Practical Guide

Several studies have shown that ultrasound guidance may contribute to improved safety, effectiveness and accuracy of musculoskeletal interventional procedures performed around the hip if compared to those performed with a landmark-guided technique. Different approaches and injectates can be used for treating hip musculoskeletal disorders. These procedures may involve injections in the hip joint, periarticular bursae, tendons, and peripheral nerves. Intra-articular hip injections are mostly used as a conservative approach for treating patients affected by hip osteoarthritis. Ultrasound-guided injection of the iliopsoas bursa is performed in patients with bursitis and/or tendinopathy, to treat those with painful prosthesis due to iliopsoas impingement, or when the lidocaine test is indicated to identify the iliopsoas as a source of pain. Ultrasound-guided interventions are routinely used in patients with greater trochanteric pain syndrome having as target the gluteus medius/minimus tendons and/or the trochanteric bursae. Ultrasound-guided fenestration and platelet-rich plasma injection are applied in patients with hamstring tendinopathy with good clinical outcomes. Last but not least, ultrasound-guided perineural injections can be used for peripheral neuropathies or blocks of the sciatic, lateral femoral cutaneous, and pudendal nerves. In this paper, we discuss the evidence and technical tips for musculoskeletal interventional procedures performed around the hip, highlighting the added value of ultrasound as an imaging guidance modality.

Meralgia Paresthetica Review: Update on Presentation, Pathophysiology, and Treatment

Purpose of Review

Meralgia paresthetica (MP) is a condition characterized by paresthesias, neuropathic pain, and alterations in sensorium of the anterolateral thigh secondary to impingement of the lateral femoral cutaneous nerve (LFCN). MP is generally diagnosed by clinical history and is often a diagnosis of exclusion. When diagnosis remains a challenge, diagnostic modalities such as ultrasound, MRI, electromyography, and nerve conduction studies have been utilized as an adjunct. This review summarizes the most recent medical literature regarding MP, its pathophysiology, presentation, and current treatment options.

Recent Findings

Treatment options for patients with MP range from lifestyle modifications and conservative management to surgical procedures. Initial management is often conservative with symptoms managed with medications. When conservative management fails, the next step is regional blocks followed by surgical management. The conflicting data for treatment options for MP highlight how the evidence available does not point to a single approach that's universally effective for treating all patients with MP.

Summary

Despite the apparent success at treating MP with regional blocks and surgical interventions, much remains to be known about the dosing, frequency, and optimal interventions due to the inconclusive results of current studies. Further research including randomized controlled trials are needed to better understand the most optimal treatment options for MP including studies with a larger number of participants.

Treatment of idiopathic meralgia paresthetica – is there reliable evidence yet?

OBJECTIVE

Meralgia paresthetica is a common condition that is usually diagnosed by its classical clinical presentation and by exclusion of a spinal origin of pain, sensory loss, and/or paresthesias in the anterolateral thigh. Treatment modalities include conservative management, local injections, and surgical therapy. To date, no level 1 evidence exists about treatment options for idiopathic meralgia paresthetica. This review article aims to give a structured overview of epidemiology, history, anatomy, diagnostics, and treatment. It focuses on the existing literature and current developments in clinical management.

METHODS

A literature search on PubMed/MEDLINE was performed on 20 December 2021, yielding 1412 results. Abstracts were screened and classified in terms of epidemiology, anatomy, diagnostics, and treatment.

RESULTS

High-quality observational data that was included in recent meta-analyses showed satisfactory results for conservative management, injections, and surgical decompression or neurectomy, but there is some major methodological criticism. For idiopathic meralgia paresthetica, the results of surgical decompression have never been compared to those of neurectomy in a randomized setup. The only study protocol published so far does not consider any extended decompression techniques (dynamic, circumferent, proximal, and distal to the inguinal ligament). A multicenter, prospective design has never been proposed.

DISCUSSION

Reliable high-quality evidence on the treatment of idiopathic meralgia paresthetica is lacking at the current state, and challenges in clinical decision-making remain.

Increased Risk of Lateral Femoral Cutaneous Nerve Injury in Patients With Previous Hip Arthroscopy Who Underwent a Direct Anterior Approach Total Hip Arthroplasty

Purpose

To evaluate the rates of lateral femoral cutaneous nerve (LFCN) injury in patients who underwent a direct anterior approach (DAA) total hip arthroplasty (THA) with and without previous hip arthroscopy.

Methods

We retrospectively investigated consecutive DAA THAs performed by a single surgeon. These cases were grouped into patients with and without a history of previous ipsilateral hip arthroscopy. LFCN sensation was assessed during the initial follow-up (6 weeks) and 1-year (or most recent) follow-up visits. The incidence and character of LFCN injury was compared between the 2 groups.

Results

In total, 166 patients underwent a DAA THA with no previous hip arthroscopy, and 13 had a history of previous arthroscopy. Of the 179 total patients who underwent THA, 77 experienced some form of LFCN injury at initial follow-up (43%). The rate of injury for the cohort with no previous arthroscopy was 39% (n = 65/166) on initial follow-up, whereas the rate of injury for the cohort with a history of previous ipsilateral arthroscopy was 92% (n =12/13) on initial follow-up (P < .001). In addition, although the difference was not significant, 28% (n = 46/166) of the group without history of previous arthroscopy and 69% (n = 9/13) of the group with a history of previous arthroscopy had continued symptoms of LFCN injury at most recent follow-up.

Conclusions

In this study, patients who underwent hip arthroscopy before an ipsilateral DAA THA were at increased risk of LFCN injury compared with patients who underwent a DAA THA without a previous hip arthroscopy. At final follow-up of patients with initial LFCN injury, symptoms resolved in 29% (n = 19/65) of patients with no previous hip arthroscopy and 25% (n = 3/12) of patients with previous hip arthroscopy.

Level of Evidence

Level III, case-control study.

Ultrasound-Guided Hydrodissection Provides Complete Symptom Resolution in Radial Tunnel Syndrome: A Case Series and Scoping Review on Hydrodissection for Radial Nerve Pathology

ABSTRACT

This study analyzes the effectiveness of ultrasound-guided hydrodissection (HD) perineural as a treatment for radial tunnel syndrome (RTS). A literature search was performed along with retrospective analysis of local cases to assess outcomes and safety of this procedure. In the case series, surgical candidates, defined as cases with over 80% but temporary relief after diagnostic injection, were treated with ultrasound-guided HD. Of 22 patients who received ultrasound-guided diagnostic injections, 11 proceeded to HD. All HD patients experienced complete and lasting symptom resolution for a minimum of 2 years, and none required surgery. Thorough literature review provided seven studies, which fulfilled inclusion criteria. Sixty-one patients are represented in the literature. All studies reported significant benefit to pain symptoms with HD of radial nerve, with five specifying over 90% improvement. No adverse effects from HD were noted in any study. Ultrasound-guided HD of the radial tunnel has potential to be a surgery sparing treatment for RTS.

US for Traumatic Nerve Injury, Entrapment Neuropathy, and Imaging-guided Perineural Injection

US is commonly performed to help diagnose traumatic peripheral nerve injury and entrapment neuropathy, particularly with superficial nerves, where higher spatial resolution provides an advantage over MRI. Other advantages of US include dynamic evaluation, easy contralateral comparison, fewer implant contraindications, less artifact from ferromagnetic debris, and facile needle guidance for perineural injections. The authors review peripheral nerve US for traumatic peripheral nerve injury with an emphasis on injury grading and entrapment neuropathy and describe best-practice techniques for US-guided perineural injections while highlighting specific techniques and indications. Online supplemental material is available for this article. ^©RSNA, 2022.

Ultrasound of the Lateral Femoral Cutaneous Nerve: A Review of the Literature and Pictorial Essay

We review the ultrasound (US) findings in patients who present with meralgia paresthetica (MP). The anatomy of the lateral femoral cutaneous nerve at the level where the nerve exits the pelvis and potential entrapment sites that can lead to MP are discussed. A wide range of pathological cases are presented to help in recognizing the US patterns of MP. Finally, our experience with US-guided treatment is discussed.

Clinical indications for image-guided interventional procedures in the musculoskeletal system: a Delphi-based consensus paper from the European Society of Musculoskeletal Radiology (ESSR)-part VII, nerves of the lower limb

OBJECTIVES

To perform a Delphi-based consensus on published evidence on image-guided interventional procedures for peripheral nerves of the lower limb (excluding Morton's neuroma) and provide clinical indications.

METHODS

We report the results of a Delphi-based consensus of 53 experts from the European Society of Musculoskeletal Radiology who reviewed the published literature for evidence on image-guided interventional procedures offered around peripheral nerves in the lower limb (excluding Morton's neuroma) to derive their clinical indications. Experts drafted a list of statements and graded them according to the Oxford Centre for evidence-based medicine levels of evidence. Consensus was considered strong when > 95% of experts agreed with the statement or broad when > 80% but < 95% agreed. The results of the Delphi-based consensus were used to write the paper.

RESULTS

Nine statements on image-guided interventional procedures for peripheral nerves of the lower limb have been drafted. All of them received strong consensus. Image-guided pudendal nerve block is safe, effective, and well tolerated with few complications. US-guided perisciatic injection of anesthetic provides good symptom relief in patients with piriformis syndrome; however, the addition of corticosteroids to local anesthetics still has an unclear role. US-guided lateral femoral cutaneous nerve block can be used to provide effective post-operative regional analgesia.

CONCLUSION

Despite the promising results reported by published papers on image-guided interventional procedures for peripheral nerves of the lower limb, there is still a lack of evidence on the efficacy of most procedures.

KEY POINTS

• Image-guided pudendal nerve block is safe, effective, and well tolerated with few complications. • US-guided perisciatic injection of anesthetic provides good symptom relief in patients with piriformis syndrome; however, the addition of corticosteroids to local anesthetics still has an unclear role. • US-guided lateral femoral cutaneous nerve block can be used to provide effective post-operative regional analgesia. The volume of local anesthetic affects the size of the blocked sensory area.

Ultrasound-guided peripheral nerve interventions for common pain disorders

There are a number of common pain disorders that can be managed effectively by injections around or ablation of peripheral nerves. Ultrasound is a universally available imaging tool, is safe, cost-effective, and is excellent in imaging many peripheral nerves and guiding needles to the site of the nerves. This article aims to present an overview of indications and techniques of such procedures that can be effectively performed by a radiologist.

Ultrasound-guided injections in pelvic entrapment neuropathies

Pelvic entrapment neuropathies represent a group of chronic pain syndromes that significantly impede the quality of life. Peripheral nerve entrapment occurs at specific anatomic locations. There are several causes of pelvic entrapment neuropathies, such as intrinsic nerve abnormality or inflammation with scarring of surrounding tissues, and surgical interventions in the abdomen, pelvis and the lower limbs. Entrapment neuropathies in the pelvic region are not widely recognized, and still tend to be underdiagnosed due to numerous differential diagnoses with overlapping symptoms. However, it is important that entrapment neuropathies are correctly diagnosed, as they can be successfully treated. The lateral femoral cutaneous nerve, ischiadic nerve, genitofemoral nerve, pudendal nerve, ilioinguinal nerve and obturator nerve are the nerves most frequently causing entrapment neuropathies in the pelvic region. Understanding the anatomy as well as nerve motor and sensory functions is essential in recognizing and locating nerve entrapment. The cornerstone of the diagnostic work-up is careful physical examination. Different imaging modalities play an important role in the diagnostic process. Ultrasound is a key modality in the diagnostic work-up of pelvic entraptment neuropathies, and its use has become increasingly widespread in therapeutic procedures. In the article, the authors describe the background of pelvic entrapment neuropathies with special focus on ultrasound-guided injections.

Treatment of meralgia paresthetica (Lateral Femoral Cutaneous Neuropathy): A meta-analysis of ultrasound-guided injection versus surgery

PURPOSE

To compare ultrasound (US)-guided injections and surgery for the treatment of meralgia paresthetica (lateral femoral cutaneous neuropathy).

METHODS

Two reviewers, independently, up to 10 October 2020 retrieved Studies that assessed the outcome of US-guided injections and surgery for the treatment of meralgia paresthetica from major medical libraries. Predefined inclusion and exclusion criteria were adopted.

RESULTS

399 studies were initially found, and the meta-analysis was conducted on 10 studies for a total of 149 patients. US-guided injections were done in three studies, surgery in seven studies. N = 38 % (57/149) of patients were treated with US-guided injection and 62 % (92/149) were treated with surgery. After US-guided injections, 85 % (49/57) of patients were treated successfully, whereas 80 % (74/92) were treated with surgery successfully from the clinical point of view. Differences were not statistically significant even with a slight heterogeneity of studies and outcome pooled on random-effect model. No comparative cohort study or RCT was conducted.

CONCLUSION

This meta-analysis showed that there was no statistically significant difference in treatment of meralgia paresthetica with ultrasound-guided injection or surgery. A RCT to compare a standardized US-guided approach versus surgery is essential to compare these techniques properly.

Meralgia paresthetica attributable to surgery in the park-bench position

OBJECTIVE

Meralgia paresthetica (MP) is an entrapment neuropathy of the lateral femoral cutaneous nerve (LFCN). We report a rare MP complication after microvascular decompression (MVD) surgery in the park-bench position in a patient with hemi-facial spasm.

CASE

The patient was a 46-year-old female (height: 155 cm, weight: 42 kg). She was neither diabetic nor a regular alcohol user. After the first MVD for right hemifacial spasm, her symptom recurred and she underwent a second MVD procedure in the park-bench position that led to the disappearance of her hemifacial spasm. However, she complained of right antero-lateral thigh pain and dysesthesia without motor weakness. The symptom was limited to the LFCN area; pelvic compression test elicited a positive Tinel-like sign. Our preliminary diagnosis was MP. As conservative therapy was ineffective she underwent LFCN block 9 months after the second MVD procedure. Her symptom improved dramatically and we made a definitive diagnosis of MP. There has been no recurrence in the course of 30 months although she reported persistent mild dysesthesia in the LFCN area.

CONCLUSION

MP is a rare complication after MVD surgery in the park-bench position. Symptom abatement and a definitive early diagnosis can be obtained by LFCN blocks.

The Effectiveness and Safety of Commonly Used Injectates for Ultrasound-Guided Hydrodissection Treatment of Peripheral Nerve Entrapment Syndromes: A Systematic Review

Background: Peripheral nerve entrapment syndromes commonly result in pain, discomfort, and ensuing sensory and motor impairment. Many conservative measures have been proposed as treatment, local injection being one of those measures. Now with high-resolution ultrasound, anatomical details can be visualized allowing diagnosis and more accurate injection treatment. Ultrasound-guided injection technique using a range of injectates to mechanically release and decompress the entrapped nerves has therefore developed called hydrodissection or perineural injection therapy. Several different injectates from normal saline, local anesthetics, corticosteroids, 5% dextrose in water (D5W), and platelet-rich plasma (PRP) are available and present clinical challenges when selecting agents regarding effectiveness and safety.

Aims: To systematically search and summarize the clinical evidence and mechanism of different commonly used injectates for ultrasound-guided hydrodissection entrapment neuropathy treatment.

Methods: Four databases, including PubMed, EMBASE, Scopus, and Cochrane were systematically searched from the inception of the database up to August 22, 2020. Studies evaluating the effectiveness and safety of different commonly used injectates for ultrasound-guided hydrodissection entrapment neuropathy treatment were included. Injectate efficacy presents clinical effects on pain intensity, clinical symptoms/function, and physical performance, electrodiagnostic findings, and nerve cross-sectional areas. Safety outcomes and mechanism of action of each injectate were also described.

Results: From ten ultrasound-guided hydrodissection studies, nine studies were conducted in carpal tunnel syndrome and one study was performed in ulnar neuropathy at the elbow. All studies compared different interventions with different comparisons. Injectates included normal saline, D5W, corticosteroids, local anesthetics, hyaluronidase, and PRP. Five studies investigated PRP or PRP plus splinting comparisons. Both D5W and PRP showed a consistently favorable outcome than those in the control group or corticosteroids. The improved outcomes were also observed in comparison groups using injections with normal saline, local anesthetics, or corticosteroids, or splinting. No serious adverse events were reported. Local steroid injection side effects were reported in only one study.

Conclusion: Ultrasound-guided hydrodissection is a safe and effective treatment for peripheral nerve entrapment. Injectate selection should be considered based on the injectate mechanism, effectiveness, and safety profile.

Role of ultrasound-guided perineural injection of the posterior antebrachial cutaneous nerve for diagnosis and potential treatment of chronic lateral elbow pain

OBJECTIVE

To examine diagnostic and therapeutic utility of novel ultrasound-guided perineural injection of posterior antebrachial cutaneous nerve in chronic lateral elbow pain.

MATERIALS AND METHODS

We performed a retrospective analysis of ultrasound-guided perineural injection of the posterior antebrachial cutaneous nerve with local anesthetic with or without corticosteroid in patients with chronic lateral elbow pain. Data variables collected included patient demographics, illness course, diagnostic ultrasound findings, immediate pre- and post-injection pain using numeric rating pain scale between 0 and 10, injection complications, and post-injection outcomes.

RESULTS

Fifteen patients (9 females and 6 males) with average age 46.9 (range 16-69 years) underwent 20 perineural injections between 2009 and 2019. Patients had on average 84% reduction in pain immediately after the injection (median pre- and post-procedure numeric rating pain scale of 6 and 0, respectively, p < 0.001). Patients had pain relief for an average of 15 h (range 2-48 h) when only local anesthetic was injected, compared with average pain relief of 26.5 days (range 2 h-43 days) when local anesthetic was combined with corticosteroid, p = 0.01.

CONCLUSION

Novel ultrasound-guided perineural anesthetic injections around the posterior antebrachial cutaneous nerve can be performed safely and have diagnostic and potentially therapeutic utility in select patients with chronic refractory lateral elbow pain.

Meralgia paresthetica caused by inguinal lymphadenopathy related to tinea pedis infection: A case report

Mechanical compression at any point along the lateral femoral cutaneous nerve (LFCN) may result in meralgia paresthetica (MP). A 54-year-old male patient presented with pain and tingling on the anterolateral side of thigh. After excluding other causes of pain radiating to legs, he was diagnosed with MP. Inguinal lymphadenopathy which caused the compression of LFCN was found on ultrasonographic examination. Tinea pedis infection was also identified during the detailed investigation for lymphadenopathy. Associated MP symptoms partially resolved immediately after ultrasound-guided LFCN block and a complete recovery was achieved after the treatment of tinea pedis.

Review of Ilioinguinal Nerve Blocks for Ilioinguinal Neuralgia Post Hernia Surgery

PURPOSE OF REVIEW

The purpose of this review is to evaluate the current evidence on ultrasound-guided ilioinguinal nerve blocks for ilioinguinal neuralgia post hernia surgery.

METHODS

A literature search was performed to find all relevant case reports, case series, prospective or retrospective cohort studies, and randomized controlled trials (RCTs) where ultrasound-guided or landmark-based ilioinguinal nerve blocks were used for ilioinguinal neuralgia post-inguinal hernia surgery.

RECENT FINDINGS

A total of six studies were identified with suitable data for inclusion. Three studies were retrospective, two studies were prospective, and one study was a randomized controlled trial. A total of 133 subjects were enrolled across these studies. Approximately 55-70% had a beneficial analgesic response to treatment. No major complications were reported in these studies. Ultrasound- and landmark-based ilioinguinal nerve blocks are safe and effective for pain relief post inguinal hernia surgery. Although there were two studies that did not show a statically significant difference in both techniques, the ultrasound-guided injection has the advantage of direct visualization of pathology, more accurate needle placement, and decreased risks of intravascular injections.

Carpal Tunnel Syndrome and Meralgia Paresthetica in Pregnancy

Importance

Carpal tunnel syndrome and meralgia paresthetica are 2 common neuropathies complicating pregnancy. Each of these causes significant discomfort but can be diagnosed and treated safely during pregnancy.

Objective

This article outlines the existing literature diagnosis, treatment, and prognosis of carpal tunnel syndrome and meralgia paresthetica, specifically looking at the implications during pregnancy. The aim is to provide a reference for physicians diagnosing and treating neuropathies in pregnant patients.

Evidence Acquisition

Existing literature on neuropathies during pregnancy, clinical presentation, and treatment options for both carpal tunnel syndrome and meralgia paresthetica was reviewed through a MEDLINE and PubMed search. Referenced articles were reviewed and used as primary source materials as appropriate.

Results

Carpal tunnel syndrome affects individuals of all ages and sexes but is more prevalent in women, particularly during pregnancy. Meralgia paresthetica can occur in various circumstances but is most commonly associated with prolonged second stage in lithotomy position. Multiple clinical signs and neurologic tests are useful to establish the diagnosis of either neuropathy. Effective treatment for carpal tunnel syndrome includes wrist splints, steroid and lidocaine injections, and release surgery. Optimal treatment of meralgia paresthetica remains controversial but includes nerve block injections and active release techniques.

Conclusions and Relevance

Neuropathies are common in pregnancy and can result in significant impairment. Accurate diagnosis is possible during pregnancy and can usually be accomplished with bedside neurologic tests. Treatment options can be safely considered during pregnancy and can result in symptomatic improvement and reduction in chronic symptoms.

Ultrasound-Guided Perineural Injection for Pronator Syndrome Caused by Median Nerve Entrapment

Patients and physicians have increasingly sought minimally invasive procedures such as ultrasound-guided injection for the treatment of peripheral nerve entrapment syndromes. In this series, we assessed subjective outcome data in 14 patients who underwent ultrasound-guided perineural hydrodissection and steroid injection for pronator syndrome secondary to median nerve entrapment in the pronator tunnel. Excellent symptomatic relief (≥75% improvement) was achieved in 70% of nerves with 3-month follow-up data, with no significant change in symptoms between 3 and 6 months. These outcomes suggest that this technique could play a role in the management of pronator syndrome due to median nerve entrapment.

Meralgia paresthetica: Nerve stimulator-guided injection with methylprednisolone/lidocaine, a double-blind randomized placebo-controlled study

BACKGROUND

Meralgia paresthetica is a mononeuropathy of the lateral femoral cutaneous nerve. A common therapy is injection with corticosteroids. The goal of this study was to analyze the effect of injection with methylprednisolone/lidocaine vs placebo.

METHODS

After randomization, 10 patients received a nerve stimulator-guided injection with methylprednisolone/lidocaine, and 10 patients received saline. The primary outcome measure was pain (visual analogue scale, VAS).

RESULTS

In the placebo group, there was a significant pain reduction (baseline VAS, 6.8; VAS week 12, 4.3; P = .014). The VAS score in the methylprednisolone group did not show a significant reduction (baseline VAS, 7.4; VAS week 12, 4.8; P = .053). There was no significant difference in pain reduction between the groups.

CONCLUSIONS

We found no objective evidence for benefit from nerve stimulator-guided injection with corticosteroids in meralgia paresthetica, although this study is limited by a small sample size. Future placebo-controlled studies using ultrasound-guided injection are warranted.

The primary role of radiological imaging in the diagnosis of rare musculoskeletal diseases. Emphasis on ultrasound

Objective: In July 2017 a multidisciplinary clinical Center specialized in rare diseases was activated. A rare disease can involve the musculoskeletal system. A multimodality musculoskeletal imaging approach allows for a rapid diagnosis. The purpose of this study was to assess when musculoskeletal radiology, ultrasound in particular, plays a primary role in the diagnostic path of a rare disease. Methods and materials: The Center included a list of 621 main rare diseases. Pathologies in which radiology has a primary diagnostic role were extracted from the list. From September 2017 to January 2018 all conditions involving the musculoskeletal system, including the peripheral nervous system, were systematically evaluated by one radiologist. The second radiologist, an official consultant of the Center, verified the list for consistency. Descriptive analysis was performed. Results: A total of 101/621 (16%) rare diseases can be diagnosed for the first time in the diagnostic path of the patient with medical imaging. A total of 36/101 (36%) rare diseases involve the musculoskeletal system. A total of 14/36 (39%) are pediatric diseases, 10/36 (28%) are adult age diseases, while 12/36 (33%) diseases affect all ages. A total of 23/36 (64%) of the selected rare diseases could be diagnosed with MRI, 19/36 (53%) with CT, 23/36 (64%) with X-ray, 9/36 (25%) with an US, and 1/36 (3%) with PET. Conclusions: Musculoskeletal imaging could be important for a non-invasive diagnosis in up to 36/101 (36%) rare diseases, as well as for outcome prediction, especially in pediatrics. Musculoskeletal imaging plays a crucial role in the diagnosis of rare diseases and could strongly influence the clinical pathway. Ultrasound is crucial in up to 25% of patients with rare diseases affecting the musculoskeletal system.

Nerve hydrodissection for carpal tunnel syndrome: A prospective, randomized, double-blind, controlled trial

INTRODUCTION

In this study we explored the efficacy of nerve hydrodissection for mild-to-moderate carpal tunnel syndrome (CTS).

METHODS

Thirty-four participants were randomly assigned to an intervention group or a control group. One 5-ml dose of normal saline was injected into the intracarpal and subcutaneous regions in subjects of both groups, respectively. The primary outcome measure was the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) score. Secondary outcomes were cross-sectional area of the median nerve and electrophysiological studies. Assessments were performed before the injection and at 1, 2, 3, and 6 months postintervention.

RESULTS

Compared with the control group, the intervention group showed significantly greater improvement at the second and third posttreatment months according to BCTQ severity score and at all time-points for cross-sectional area of the median nerve (P < 0.01).

DISCUSSION

Our study demonstrates the therapeutic effects of nerve hydrodissection for mild-to-moderate CTS. Muscle Nerve 59:174-180, 2019.

Lateral Femoral Cutaneous Nerve Decompression Guided by Preoperative Ultrasound Mapping

Injury to the lateral femoral cutaneous nerve (LFCN) from compression or entrapment may result in meralgia paresthetica, a painful mononeuropathy of the anterolateral thigh. Surgical decompression of the LFCN may provide relief when conservative management fails. However, the considerable anatomic variability of this nerve may complicate surgical localization and thus prolong operative time. Herein, we report the use of preoperative high-resolution ultrasonography to map the LFCN in a patient with bilateral meralgia paresthetica. This simple, noninvasive imaging technique was seen to be effective at providing precise localization of the entrapped and, in this case, bilateral anatomically variant nerves. Preoperative high-resolution ultrasound mapping of the LCFN can be used to facilitate precise operative localization in the treatment of bilateral meralgia paresthetica. This is especially useful in the setting of suspected unusual nerve anatomy.

[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 Diagnostic and Therapeutic Injections of the Hip and Groin

Hip and groin pain often presents a diagnostic and therapeutic challenge. The differential diagnosis is extensive, comprising intra-articular and extra-articular pathology and referred pain from lumbar spine, knee and elsewhere in the pelvis. Various ultrasound-guided techniques have been described in the hip and groin region for diagnostic and therapeutic purposes. Ultrasound has many advantages over other imaging modalities, including portability, lack of ionising radiation and real-time visualisation of soft tissues and neurovascular structures. Many studies have demonstrated the safety, accuracy and efficacy of ultrasound-guided techniques, although there is lack of standardisation regarding the injectates used and long-term benefit remains uncertain.

Six-month Efficacy of Perineural Dextrose for Carpal Tunnel Syndrome: A Prospective, Randomized, Double-Blind, Controlled Trial

OBJECTIVE

To assess the 6-month effectiveness of ultrasound-guided perineural injection therapy (PIT) using 5% dextrose (D5W) in patients with mild-to-moderate carpal tunnel syndrome (CTS).

PATIENTS AND METHODS

A prospective, randomized, placebo-controlled, and double-blind study was conducted between May 1, 2016, through March 30, 2017. A total of 49 participants diagnosed with mild-to-moderate CTS were randomized into D5W and control groups. Participants in the D5W group received 1 session of ultrasound-guided PIT with 5 cc of D5W, and the control group received PIT with normal saline. The visual analog scale measured pain as a primary outcome. Secondary outcomes were Boston Carpal Tunnel Syndrome Questionnaire scores, the cross-sectional area of the median nerve, and electrophysiological measurement results. Assessment was performed before injection and at 1, 3, and 6 months post-injection.

RESULTS

All patients (data from 30 wrists in each group) completed the study. Compared with the control group, at all post-injection time points, the D5W group had a significant reduction in pain and disability, improvement on electrophysiological response measures, and decreased cross-sectional area of the median nerve.

CONCLUSION

Our study reveals that ultrasound-guided PIT with D5W is an effective treatment for patients with mild-to-moderate CTS.

TRIAL REGISTRATION

www.ClinicalTrials.gov: NCT02809261.

A rare presentation of meralgia paraesthetica in limb girdle muscular dystrophy

A 44-year-old female with paraesthesia and pain on the left anterolateral thigh who had been diagnosed with limb-girdle muscular dystrophy by electromyography and muscle biopsy is presented. Neurological examination revealed atrophy of the proximal muscles of both shoulders, plus pseudo hypertrophy of both calves. Electromyography exhibited a myopathic pattern. Musculoskeletal ultrasound imaging demonstrated a fusiform nerve swelling below the inguinal ligament suggesting lateral femoral cutaneous nerve compression, consistent with meralgia paraesthetica. Treatment with a perineural injection of betamethasone dipropionate and betamethasone sodium phosphate combination, and prilocaine-HCl, under ultrasound guidance, was performed. Symptoms resolved within 6 h. At 3-week follow-up, the patient was asymptomatic, and there was no paraesthesia or pain on examination. In this case, ultrasound-guided perineural injection of the lateral femoral cutaneous nerve with local anaesthetics and steroid served both diagnostic and therapeutic functions.

Evaluating the evidence: is neurolysis or neurectomy a better treatment for meralgia paresthetica?

BACKGROUND

Meralgia paresthetica is a mononeuropathy of the lateral femoral cutaneous nerve (LCFN). Surgical treatment involves transection or decompression of the LCFN. There is no clear consensus on the superiority of one technique over the other. We performed a systematic review of the literature to answer this question.

METHODS

Eligible studies included those that compared neurolysis versus neurectomy for the treatment of meralgia paresthetica after failure of conservative therapy. Our outcome of interest was resolution of symptoms. We performed a computerized search of MEDLINE (PubMed; all years) and of the Cochrane Central Register of Controlled Trials. Eligible studies had to include the words "meralgia paresthetica" and "surgery." All patients regardless of age were included, and there was no language restriction. We then reviewed the articles' titles and abstracts. All studies that compared neurolysis to neurectomy were included in the analysis.

RESULTS

Of the studies identified, none were randomized controlled trials. There were two German language articles that were translated by a third researcher. Each study was evaluated by two independent researchers who assigned a level of evidence according to American Association of Neurologist algorithm and also performed data extraction (neurolysis vs. neurectomy and resolution of pain symptoms). Each study was found to be level four evidence.

CONCLUSION

After reviewing the data, there was insufficient evidence to recommended one method of treatment over the other. This highlights the importance of keeping a national registry in order to compare outcomes between the two methods of treatment.

Ultrasound-guided alcohol neurolysis of lateral femoral cutaneous nerve for intractable meralgia paresthetica: a case series

Meralgia paresthetica is a rare sensory entrapment neuropathy which leads to burning, tingling and numbness in the antero-lateral aspect of thigh. Mostly it runs a benign course, and responds to conservative measures. We present a case series of six patients with intractable meralgia paresthetica with severe pain over antero-lateral thigh along the distribution of lateral cutaneous nerve of thigh which was further confirmed by nerve conduction study. These patients did not respond to the oral anti-neuropathic medications. The two successive diagnostic lateral femoral cutaneous nerve block not only had confirmed the diagnosis but also provided pain relief for a few days. Then the ultrasound-guided lateral femoral cutaneous nerve neurolysis was done using 50% alcohol. In all the patients, there were more than 50% decrease in pain intensity and improvement in quality of life after the procedure, and the relief and improvement were maintained for up to 12 weeks. This case series shows ultrasound-guided lateral femoral cutaneous nerve neurolysis is a safe and effective treatment for intractable meralgia paresthetica and also provides prolonged pain relief and is a good option in avoiding the surgery. Summary points The literature on neurolysis is rare, with only few case reports. This is the first case series on this topic, and it will greatly improve the evidence that ultrasound-guided neurolysis can also be used for intractable meralgia paresthetica patients who do not respond to conservative measures before proceeding to surgery.

Update in Musculoskeletal Ultrasound Research

CONTEXT

Musculoskeletal ultrasound (US) research is expanding due to increased clinical utility of sonography.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Ultrasound is widely applied in musculoskeletal imaging and sports medicine. The real-time capabilities and favorable cost profile of US make it ideal for use in diagnosis of musculoskeletal conditions. The enthusiasm for the use of US in musculoskeletal imaging has led to an increase in US research to broaden its applications.

CONCLUSION

Several recent advances have been made in conventional and novel US imaging techniques, quantitative US imaging, and US-guided interventions.

STRENGTH OF RECOMMENDATIONS TAXONOMY SORT

C.

Technical feasibility of robot-assisted minimally-invasive neurolysis of the lateral cutaneous nerve of thigh: About a case

To limit the risk of iatrogenic neuroma and recurrence after surgical treatment of meralgia paresthetica, some authors have recently developed a technique of endoscopic neurolysis of the lateral cutaneous nerve of thigh (LCNT) below the level of the inguinal ligament. We report the case of a robot-assisted endoscopic technique underneath the inguinal ligament. A 62-year-old patient suffering of idiopathic meralgia paresthetica for the past 18 months received a Da Vinci robot-assisted minimally-invasive 10cm long neurolysis, of which 1/3 was situated above the level of the inguinal ligament and 2/3 below it. The patient was discharged the following day without complications. At 6-months follow-up the pain was rated 0/10 compared to 5/10 pre-operatively. Robot-assisted endoscopic neurolysis of the LCNT retains the advantages of conventional endoscopy and enables to approach the nerve in the most frequently compressed zone underneath the inguinal ligament. The three-dimensional view offered by robotic surgery facilitates the dissection. The superiority of this technique remains to be demonstrated by comparing it to conventional techniques.

Ultrasound-guided interventional procedures for chronic pain management

Ultrasonography has multiple advantages over traditional radiologic imaging modalities when used for interventional procedures. It allows improved visualization of the anatomy while avoiding ionizing radiation and risks associated with contrast use. It has proved superiority at accuracy of delivery and procedural effectiveness over blind procedures when used in association with interventional pain procedures. Although limited in its ability to see through bony structures, ultrasound has utility in visualizing soft tissues and vascular structures in anatomic regions of interest resulting in increased use for posterior neuraxial, periaxial, peripheral nerve and joint-related structures. Current evidence for use in these settings is presented here. In some cases, optimal utility may be improved by combining ultrasonography with other imaging modalities.

Lateral femoral cutaneous nerve injury with the direct anterior approach for total hip arthroplasty

PURPOSE

Although injury of the lateral femoral cutaneous nerve (LFCN) is a known complication after total hip arthroplasty (THA) via the direct anterior approach (DAA), the impact of this complication on postoperative quality of life (QOL) is unclear. This study aims to investigate the incidence of LFCN injury after DAA for THA, and to determine the impact of LFCN injury on QOL and hip function.

METHODS

We prospectively investigated 122 hips operated upon using the DAA regarding the incidence of LFCN injury using self-reported questionnaires, hip functional scores such as the Harris Hip Score (HHS) and the Japanese Orthopaedic Association (JOA) score, and patient-reported outcomes such as the Western Ontario and McMaster Universities Osteoarthritis Index, the Japanese Orthopaedic Association Hip disease Evaluation Questionnaire (JHEQ), and the Forgotten Joint Score-12 (FJS).

RESULTS

LFCN injury was seen in 39 hips (31.9 %). In affected hips, the leading symptom was hypo-aesthesia (46.2 %), followed by tingling or jolt-like sensation (28.2 %). There was no difference in the HHS and JOA score between those with LFCN injury and those without. There was a significant difference in the FJS-12 between the two groups (50.9 ± 25.3 for hips with LFCN injury vs 64.3 ± 25.7 without, p = 0.01). There was a non-significant tendency for patients with LFCN injury to have a lower JHEQ than those without (63.6 ± 19.6 for hips with LFCN injury vs 70.8 ± 22.9 without, p = 0.13).

CONCLUSIONS

The incidence of LFCN injury decreased QOL but not hip function after DAA for THA.

Meralgia paraesthetica: Ultrasound-guided injection at multiple levels with 12-month follow-up

OBJECTIVES

To evaluate the efficacy of ultrasound (US)-guided injections around the lateral femoral cutaneous nerve (LFCN) at different levels in meralgia paraesthetica (MP) patients.

METHODS

The study was approved by the university ethics committee and informed oral and written consent were obtained from all patients. Between June 2008 and August 2013, 20 patients with symptoms of MP, including nine men (mean age, 61.33 years) and 11 women (mean age 61.18 years), were treated with US-guided injection of steroids along the LFCN at three different levels in a mean of 2.25 sessions. A visual analogue scale (VAS) was used to measure symptoms before, immediately after and 12 months after treatment.

RESULTS

Complete resolution of symptoms was documented in 15/20 patients (mean VAS decreased from 82 to 0), and partial resolution in the remaining five (mean VAS decreased from 92 to 42), which was confirmed at 12-month follow-up. By using the different levels of injection approach overall significantly better symptom relief was obtained (p < 0.05).

CONCLUSION

The outcome of US-guided injection along the LFCN can be further improved by injections at different levels (p < 0.05), which was confirmed at 12-month long-term follow-up.

KEY POINTS

Meralgia paraesthetica is an entrapment neuropathy of the lateral femoral cutaneous nerve. Ultrasound proved effective in diagnosis and in guiding injection therapy. Injection at the anterior superior iliac spine has been used previously. Multiple injections along the nerve course were used in this study. Long-term follow-up (12 months) confirmed the results.

Anatomical study of the iliohypogastric, ilioinguinal, and genitofemoral nerves using high-resolution ultrasound

INTRODUCTION

In this study we aimed to determine whether high-resolution ultrasound (US) can identify the iliohypogastric (IH), ilioinguinal (II), and genitofemoral (GF) nerves and their relations.

METHODS

This investigation, initially undertaken in cadavers, was followed by a high-resolution US study in 30 healthy adult volunteers (180 nerves) by 2 musculoskeletal radiologists on separate occasions, using 2 different approaches (proximal to distal and distal to proximal). A 0-3 scale was used to assess nerve visibility. Location and course of the IH, II, and GF nerves and their relations to adjacent anatomical structures were analyzed.

RESULTS

Nerves and their terminal branches were better visualized with the distal-to-proximal approach (P < 0.05). Visualization of the terminal branches was possible in up to 60% of volunteers.

CONCLUSIONS

High-resolution ultrasound (US) can identify the IH, II, and GF nerves at the level of the abdominal wall and the terminal branches in the majority of volunteers.

Meralgia paresthetica-like symptoms following epidural analgesia after total knee arthroplasty

Meralgia paresthetica (MP) is generally caused by entrapment of the lateral femoral cutaneous nerve (LFCN), and presents with pain and paresthesia in the anterolateral thigh. This paper describes a patient who had MP-like symptoms as a result of continuous epidural analgesia after total knee arthroplasty. The patient with pre-existing left foraminal stenosis at L3-L4 and disc herniations at L4-5 did not complain of paresthesia or pain during the combined spinal-epidural anesthetic procedure. However, during epidural analgesia on the second post-operative day, he complained of paresthesia and pain in the anterolateral thigh of the contralateral leg. Electromyography showed a neurogenic lesion at the level of L3. Although an ultrasound-guided diagnostic block of the LFCN was performed twice post-operatively, the patient's symptoms persisted. The symptoms gradually resolved 12 months after the surgery. In our case, we suggest that the continuous epidural infusate caused neural ischemia of the L3 nerve root by a compressive effect.