Diagnostic Approach to Lower Limb Entrapment Neuropathies: A Narrative Literature Review

Entrapment neuropathies of the lower limb are a misunderstood and underdiagnosed group of disorders, characterized by pain and dysesthesia, muscular weakness, and specific provoking movements on physical examination. The most frequent of these syndromes encountered in clinical practice are fibular nerve entrapment, proximal tibial neuropathy, sural nerve neuropathy, deep gluteal syndrome or sciatic nerve entrapment, and lateral femoral cutaneous nerve entrapment, also known as meralgia paresthetica. These are commonly mistaken for lumbar plexopathies, radiculopathies, and musculotendinous diseases, which appear even more frequently and have overlapping clinical presentations. A comprehensive anamnesis, physical examination, and electrodiagnostic studies should help clarify the diagnosis. If the diagnosis is still unclear or a secondary cause of entrapment is suspected, magnetic resonance neurography, MRI, or ultrasonography should be conducted to clarify the etiology, rule out other diseases, and confirm the diagnosis. The aim of this narrative review was to help clinicians gain familiarity with this disease, with an increase in diagnostic confidence, leading to early diagnosis of nerve damage and prevention of muscle atrophy. We reviewed the epidemiology, anatomy, pathophysiology, etiology, clinical presentation, and EDX technique and interpretation of the entrapment neuropathies of the lower limb, using articles published from 1970 to 2022 included in the Pubmed, MEDLINE, Cochrane Library, Google Scholar, EMBASE, Web of Science, and Scopus databases.

Sickness absence and disability pension after carpal tunnel syndrome diagnosis: A register-based study of patients and matched references in Sweden

Aims: The aim of this study was to examine sickness absence and disability pension (SA/DP) during working lifespan among individuals diagnosed with carpal tunnel syndrome (CTS) and their matched references, accounting for sociodemographic factors. Methods: We used a register cohort of 78,040 individuals aged 19-60 years when diagnosed with CTS in secondary health care (hospitals and outpatient specialist health care) and their 390,199 matched references from the general population in 2001-2010. Sociodemographic factors and SA/DP net days during a three-year follow-up were included. Negative binomial regression was used. Results: For those not on DP at inclusion, the average number of SA/DP days per person-year was 58 days (95% confidence interval (CI) 56-60 days) among individuals with CTS and 20 days (95% CI 19-21 days) among the matched references. Among both groups, these numbers increased with age and were higher among women than among men. The rate ratio (RR) of SA/DP days was threefold higher among people with CTS than among the matched references (adjusted RR=3.00, 95% CI 2.91-3.10) Moreover, compared to the matched references, the RR for SA/DP was higher among men with CTS (RR=3.86, 95% CI 3.61-4.13) than among women with CTS (RR=2.69, 95% CI 2.59-2.78). The association between CTS and the number of SA/DP days was smaller among older age groups. Sociodemographic factors were similarly associated with SA/DP among people with and without CTS. Conclusions: Numbers of SA/DP days were higher among people with CTS than their matched references in all age groups, particularly among individuals in their early work careers, highlighting public-health relevance of the findings.

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

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

Upper limb entrapment neuropathies in multiple sclerosis

Introduction

Entrapment neuropathies of upper limbs such as carpal tunnel and cubital tunnel syndromes are common in the general population. Identification of entrapment neuropathies of upper limbs in patients with multiple sclerosis can be clinically challenging as signs and symptoms could be attributed to multiple sclerosis. People at later stages of multiple sclerosis use mobility aids and wheelchairs. Weakness of hands in this cohort due to entrapment neuropathies could adversely affect their mobility and independence.

Methods

This was a retrospective review of records of patients with multiple sclerosis referred for clinical neurophysiological studies with clinical suspicion of upper limb entrapment neuropathies over a 10-year period. We collected demographic details, clinical features, clinical neurophysiological data and details of aids and appliances used for mobility.

Results

Among 71 patients, 38 (53.5%) patients had at least one entrapment neuropathy of upper limb confirmed by clinical neurophysiological studies. Twelve (31%) patients had median nerve entrapment, 20 (53%) had ulnar nerve entrapment and six (16%) had both. Risk of ulnar nerve entrapment was significantly higher in patients using a powered wheelchair (odds ratio 5.7, 95% confidence interval (1.7-18.7, p = 0.0037).

Discussion

Entrapment neuropathies should be considered in patients with multiple sclerosis reporting sensory and motor symptoms of hands.

Superficial brachial artery: a possible cause for idiopathic median nerve entrapment neuropathy

Nerve entrapment syndromes occur because of anatomic constraints at specific locations in both upper and lower limbs. Anatomical locations prone to nerve entrapment syndromes include sites where a nerve courses through fibro-osseous or fibromuscular tunnels or penetrates a muscle. The median nerve (MN) can be entrapped by the ligament of Struthers; thickened biceps aponeurosis; between the superficial and deep heads of the pronator teres muscle and by a thickened proximal edge of flexor digitorum superficialis muscle. A few cases of MN neuropathies encountered are reported to be idiopathic. The superficial branchial artery (SBA) is defined as the artery running superficial to MN or its roots. This divergence from normal anatomy may be the possible explanation for idiopathic MN entrapment neuropathy. This study presents three cases with unilateral presence of the SBA encountered during routine undergraduate dissection at the University of Johannesburg. Case 1 - SBA divided into radial and ulnar arteries. Brachial artery (BA) terminated as deep brachial artery. Case 2 - SBA continued as radial artery (RA). BA terminated as ulnar artery (UA), anterior and posterior interosseous arteries. Case 3 - SBA continued as UA. BA divided into radial and common interosseous arteries. Arteries that take an unusual course are more vulnerable to iatrogenic injury du-ring surgical procedures and may disturb the evaluation of angiographic images during diagnosis. In particular, the presence of SBA may be acourse of idiopathic neuropathies.

Treatment of proximal hamstring tendinopathy-related sciatic nerve entrapment: presentation of an ultrasound-guided "Intratissue Percutaneous Electrolysis" application

BACKGROUND

Proximal Hamstring Tendinopathy-related Sciatic Nerve Entrapment (PHTrSNE) is a neuropathy caused by fibrosis interposed between the semimembranosus tendon and the sciatic nerve, at the level of the ischial tuberosity.

METHODS

Ultrasound-guided Intratissue Percutaneous Electrolysis (US-guided EPI) involves galvanic current transfer within the treatment target tissue (fibrosis) via a needle 0.30 to 0.33 mm in diameter. The galvanic current in a saline solution instantly develops the chemical process of electrolysis, which in turn induces electrochemical ablation of fibrosis. In this article, the interventional procedure is presented in detail, and both the strengths and limits of the technique are discussed.

RESULTS

US-guided EPI eliminates the fibrotic accumulation that causes PHTrSNE, without the semimembranosus tendon or the sciatic nerve being directly involved during the procedure. The technique is however of limited use in cases of compression neuropathy.

CONCLUSION

US-guided EPI is a technique that is quick to perform, minimally invasive and does not force the patient to suspend their activities (work or sports) to make the treatment effective. This, coupled to the fact that the technique is generally well-tolerated by patients, supports use of US-guided EPI in the treatment of PHTrSNE.

Assessment of the utility of ultrasonography with high-frequency transducers in the diagnosis of postoperative neuropathies

The primary aim of this paper was to assess the relevance of high-frequency ultrasound examination in qualifying patients for either surgical or conservative treatment of postoperative peripheral neuropathies. The study was conducted in a group of 71 patients who in 2009–2011 were referred to ultrasound examinations due to a clinical suspicion of peripheral neuropathies. For the purposes of this analysis, the suspected postoperative neuropathies were divided into three groups: after surgical treatment of the median nerve (1), after surgical treatment of the ulnar nerve (2) and other postoperative neuropathies (3). All patients underwent the interview, physical examination and ultrasound examination. The ultrasound examinations were performed with Esaote MyLab 50 and MyLab 60 systems. Based on the clinical and US examinations, the patients were qualified for either surgical (51 cases) or conservative treatment (20 cases). An EMG examination was also performed in certain patients (60 cases). Mean values of cross-sectional areas and diameters of the nerve trunks were calculated in individual pathology groups. The ultrasound features of the peripheral nerves analyzed in the study, such as echostructure, notch sign, hyperemia and continuity of the transverse ligament, were divided into subgroups. Moreover, the frequency of adhesions between the nerve trunks and adjacent tissues, occurrence of pain on compression with a transducer and instability of the ulnar nerve as well as angulation of the posterior interosseous nerve in a dynamic examination was calculated. The analyses of the collected material were performed by means of descriptive statistics. The results of clinical and surgical verification were consistent with ultrasound findings in 100% of cases. The results indicate that high-frequency ultrasonography is a valuable method in qualifying patients for various types of treatment of peripheral postoperative neuropathies.

Ultrasound assessment on selected peripheral nerve pathologies. Part I: Entrapment neuropathies of the upper limb - excluding carpal tunnel syndrome

Ultrasound (US) is one of the methods for imaging entrapment neuropathies, post-traumatic changes to nerves, nerve tumors and postoperative complications to nerves. This type of examination is becoming more and more popular, not only for economic reasons, but also due to its value in making accurate diagnosis. It provides a very precise assessment of peripheral nerve trunk pathology – both in terms of morphology and localization. During examination there are several options available to the specialist: the making of a dynamic assessment, observation of pain radiation through the application of precise palpation and the comparison of resultant images with the contra lateral limb. Entrapment neuropathies of the upper limb are discussed in this study, with the omission of median nerve neuropathy at the level of the carpal canal, as extensive literature on this subject exists. The following pathologies are presented: pronator teres muscle syndrome, anterior interosseus nerve neuropathy, ulnar nerve groove syndrome and cubital tunnel syndrome, Guyon's canal syndrome, radial nerve neuropathy, posterior interosseous nerve neuropathy, Wartenberg's disease, suprascapular nerve neuropathy and thoracic outlet syndrome. Peripheral nerve examination technique has been presented in previous articles presenting information about peripheral nerve anatomy [Journal of Ultrasonography 2012; 12 (49): 120–163 – Normal and sonographic anatomy of selected peripheral nerves. Part I: Sonohistology and general principles of examination, following the example of the median nerve; Part II: Peripheral nerves of the upper limb; Part III: Peripheral nerves of the lower limb]. In this article potential compression sites of particular nerves are discussed, taking into account pathomechanisms of damage, including predisposing anatomical variants (accessory muscles). The parameters of ultrasound assessment have been established – echogenicity and echostructure, thickness (edema and related increase in the cross sectional area of the nerve trunk), vascularization and the reciprocal relationship with adjacent tissue.