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

High-resolution ultrasound in the evaluation of the adult hip

This paper reviews ultrasound of the hip, which is a commonly requested examination for symptomatic hip issues. This includes both intra-articular and extra-articular causes of hip pain. Ultrasound is easily accessible, lacks radiation exposure, and allows for evaluation of the contralateral hip as well as assessment of dynamic maneuvers. Ultrasound can be used to guide interventional procedures. Ultrasound of the hip can be challenging due to the deep location of structures and complex anatomy. Typically, high-frequency transducers are used to examine the hip, however the choice of ultrasound transducer depends on the patient's body habitus, with lower frequency transducers required to penetrate deep structures in obese patients. It is important to have an approach to ultrasound of the hip which includes assessment of the anterior, lateral, posterior, and medial aspects of the hip. The technique and relevant anatomy of each of these compartments are discussed as well as the use of Doppler examination of the hip. Several dynamic maneuvers can be performed to help determine the cause of hip pathology in various locations, and these are described and illustrated. Ultrasound is useful for guided procedures about the hip, and these indications will be reviewed.

Meralgia Paresthetica: Relevance, Diagnosis, and Treatment

BACKGROUND

Pain and sensory disturbance in the distribution of the lateral femoral cutaneous nerve in the ventrolateral portion of the thigh is called meralgia paresthetica (MP). The incidence of MP has risen along with the increasing prevalence of obesity and diabetes mellitus and was recently estimated at 32 new cases per 100 000 persons per year. In this review, we provide an overview of current standards and developments in the diagnosis and treatment of MP.

METHODS

This review is based on publications retrieved by a selective literature search, with special attention to meta-analyses, systematic reviews, randomized and controlled trials (RCTs), and prospective observational studies.

RESULTS

The diagnosis is mainly based on typical symptoms combined with a positive response to an infiltration procedure. In atypical cases, electrophysiological testing, neurosonography, and magnetic resonance imaging can be helpful in establishing the diagnosis. The literature search did not reveal any studies of high quality. Four prospective observational studies with small case numbers and partly inconsistent results are available. In a meta-analysis of 149 cases, pain relief was described after infiltration in 85% of cases and after surgery in 80%, with 1-38 months of follow-up. In another meta-analysis of 670 cases, there was pain relief after infiltration in 22% of cases, after surgical decompression in 63%, and after neurectomy in 85%. Hardly any data are available on more recent treatment options, such as radiofrequency therapy, spinal cord stimulation, or peripheral nerve stimulation.

CONCLUSION

The state of the evidence is limited in both quantity and quality, corresponding to evidence level 2a for surgical and non-surgical methods. Advances in imaging and neurophysiological testing have made the diagnosis easier to establish. When intervention is needed, good success rates have been achieved with surgery (decompression, neurectomy), and variable success rates with infiltration.

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.

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.

EULAR points to consider for the use of imaging to guide interventional procedures in patients with rheumatic and musculoskeletal diseases (RMDs)

OBJECTIVES

To develop evidence-based Points to Consider (PtC) for the use of imaging modalities to guide interventional procedures in patients with rheumatic and musculoskeletal diseases (RMDs).

METHODS

European Alliance of Associations for Rheumatology (EULAR) standardised operating procedures were followed. A systematic literature review was conducted to retrieve data on the role of imaging modalities including ultrasound (US), fluoroscopy, MRI, CT and fusion imaging to guide interventional procedures. Based on evidence and expert opinion, the task force (25 participants consisting of physicians, healthcare professionals and patients from 11 countries) developed PtC, with consensus obtained through voting. The final level of agreement was provided anonymously.

RESULTS

A total of three overarching principles and six specific PtC were formulated. The task force recommends preference of imaging over palpation to guide targeted interventional procedures at peripheral joints, periarticular musculoskeletal structures, nerves and the spine. While US is the favoured imaging technique for peripheral joints and nerves, the choice of the imaging method for the spine and sacroiliac joints has to be individualised according to the target, procedure, expertise, availability and radiation exposure. All imaging guided interventions should be performed by a trained specialist using appropriate operational procedures, settings and assistance by technical personnel.

CONCLUSION

These are the first EULAR PtC to provide guidance on the role of imaging to guide interventional procedures in patients with RMDs.

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.

Value of imaging to guide interventional procedures in rheumatic and musculoskeletal diseases: a systematic literature review informing EULAR points to consider

OBJECTIVES

To summarise current data on the value of imaging to guide interventional procedures in patients with rheumatic and musculoskeletal disease (RMDs) informing an European Alliance of Associations for Rheumatology taskforce.

METHODS

A systematic literature review was conducted to retrieve prospective and retrospective studies published in English and comparing different (imaging) techniques, different settings and procedural protocols to guide interventions in patients with RMDs. MEDLINE, EMBASE, the Cochrane Library and Epistemonikos databases were searched through October 2021. Risk of bias (RoB) was assessed using the Cochrane RoB tool for randomised trials V.2 (ROB2), the RoB tool for Non-Randomised Studies of Interventions and the appraisal tool for cross-sectional studies.

RESULTS

Sixty-six studies were included (most with moderate/high RoB); 49 were randomised controlled trials, three prospective cohort studies and 14 retrospective studies. Fifty-one studies compared either one imaging technique with another imaging technique, or with palpation-guided interventions. Ultrasound (US) was most frequently studied (49/51), followed by fluoroscopy (10/51). Higher accuracy was found for US or fluoroscopy compared with palpation-guided interventions. Studies comparing different imaging techniques (12/51) did not endorse one specific method. Different settings/equipment for imaging-guided procedures (eg, automatic vs manual syringes) were investigated in three studies, reporting heterogeneous results. Fifteen studies compared different imaging-guided procedures (eg, intra-articular vs periarticular injections).

CONCLUSION

Higher accuracy of needle positioning at joints and periarticular structures was seen in most studies when using imaging (especially US) guidance as compared with palpation-guided interventions with the limitation of heterogeneity of data and considerable RoB.

Preoperative ultrasound to map the three-dimensional anatomical distribution of the lateral femoral cutaneous nerve in direct anterior approach for total hip arthroplasty

Background

The postoperative complaints of hypoesthesia or a burning sensation due to lateral femoral cutaneous nerve (LFCN) injury in patients are not yet solved. The present study aimed to identify the three-dimensional (3D) distribution of LFCN using preoperative ultrasound and evaluate the rate of injury in direct anterior approach for total hip arthroplasty.

Methods

A total of 59 patients (28 males and 31 females, age 69.0 ± 4.6 years, BMI 24.7 ± 3.0 kg/m²) were randomly allocated to the ultrasound group and 58 patients (28 males and 30 females, age 68.5 ± 4.5 years, BMI 24.8 ± 2.8 kg/m²) were in the control group. Surgeons received the data of 3D distribution of LFCN only in the ultrasound group before surgery with respect to the direction, the depth on the skin, and the length to tensor fasciae latae (TFL). The anatomical characteristics of LFCN in the surgical region were summarized. At 1 and 3 months of post surgery, the rate of LFCN injury and abnormal sensitive area was evaluated in both groups.

Results

There was a significant consistency in gender, age and BMI of these two groups (P > 0.05). Based on the data from the ultrasound group, over 90% of patients had one or two branches of LFCN. LFCN always courses in the fascia layer, the depth ranged from 6.8 ± 2.6 (3.0–12.0) mm to 11.1 ± 3.4 (4.0–17.0) mm and depended on the thickness of the subcutaneous fat, and length was 3.3 ± 4.6 (− 5.0–10.0) mm at proximal part and − 2.7 ± 4.7 (− 10.0–8.0) at distal end to the medial edge of TFL. Both the rate of LFCN injury and abnormal sensory area in the ultrasound group was significantly lower than those in the control group (3.4% vs. 25.9%, P = 0.001, at 1 month; 3.4% vs. 22.4%, P = 0.005, at 3 months).

Conclusions

LFCN mostly courses along the medial border of TFL in the fascia layer. The 3D distribution of LFCN using preoperative ultrasound mapping could help the surgeons to evaluate the risk of injury preoperatively and decrease the rate of injury during the operation. However, some branch injuries, especially for the fan type LFCN, could not be avoided.

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 treated by injection, decompression, and neurectomy: a systematic review and meta-analysis of pain and operative outcomes

OBJECTIVE

Meralgia paresthetica is caused by entrapment of the lateral femoral cutaneous nerve (LFCN) and often presents with pain. Multiple treatment options targeting the LFCN can be pursued to treat the pain should conservative measures fail, with the most common options being injection, neurolysis, and neurectomy. However, their efficacy in causing pain relief and their clinical outcomes have yet to be directly compared. The aim of this study was to interrogate the contemporary literature and quantitatively define how these options compare.

METHODS

The electronic databases Ovid Embase, PubMed, SCOPUS, and the Cochrane Library were interrogated from inception to May 2020 following the PRISMA guidelines. Candidate articles were screened against prespecified criteria. Outcome data were abstracted and pooled by random-effects meta-analysis of proportions.

RESULTS

There were 25 articles that satisfied all criteria, reporting outcomes for a total of 670 meralgia paresthetica patients, with 78 (12%) treated by injection, 496 (74%) by neurolysis, and 96 (14%) by neurectomy. The incidence of complete pain relief was 85% (95% CI 71%-96%) after neurectomy, 63% (95% CI 56%-71%) after neurolysis, and 22% (95% CI 13%-33%) after injection, which were all statistically different (p < 0.01). The incidence of revision procedures was 12% (95% CI 4%-22%) after neurolysis and 0% (95% CI 0%-2%) after neurectomy, which were significantly lower than 81% (95% CI 64%-94%) after injection (p < 0.01). The incidences of treatment complications were statistically comparable across all three treatments, ranging from 0% to 5% (p = 0.34).

CONCLUSIONS

There are multiple treatment options to target pain in meralgia paresthetica. The incidence of complete pain relief appears to be the greatest among the 3 interventions after neurectomy, accompanied by the lowest incidence of revision procedures. These findings should help inform patient preference and expectations. Greater exploration of the anatomical rationale for incomplete pain relief after surgical intervention will assist in optimizing further surgical treatment for meralgia paresthetica.

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.

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.

Ultrasound Imaging of Disorders of Small Nerves of the Extremities: Less Recognized Locations

Ultrasound is a well-proven imaging modality for showing peripheral nerve disorders and guiding perineural injections. The aim of this review is to focus on small peripheral nerve abnormalities, which are usually not recognized by sonologists. In fact, most of these small nerves have a tiny diameter (<2 mm), and their anatomy is less familiar. We describe the most common causes of small peripheral nerve disorders, providing an accurate description of their anatomic locations and relationships with adjacent structures; we also focus on technical hints that may help in their evaluation.

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.