Letter to the Editor: Adjusting Anterior Thigh Muscle Measurements Using Ultrasound in Sarcopenia

We have read with great interest the recently published article by Tsukasaki et al (1). We congratulate the authors for drawing attention to regional muscle mass measurements for evaluating sarcopenia. As they highlighted, age-related muscle loss occurs initially in the anterior thigh muscles that predominantly contain fast-twitch (type II) fibers (2). Therefore, regional muscle mass and functional assessments are important for the early diagnosis and follow-up of sarcopenia (2). In this regard, computed tomography (CT), magnetic resonance imaging, ultrasound (US) and dual-energy X-ray absorptiometry (DXA) techniques give opportunity for regional muscle mass measurements. Likewise, the authors compared the relationships among regional/total muscle mass measurements, muscle power, strength and performance tests. Although we agree with them in general, we would like to add further.

Ultrasonographic Evaluation of the Radial Nerves in Patients with Unilateral Refractory Lateral Epicondylitis

Objective

To evaluate the possible radial nerve entrapment of patients with unilateral refractory lateral epicondylitis (LE) by using ultrasound (US) and electroneuromyography.

Design

Cross-sectional study.

Setting

Three physical medicine and rehabilitation departments.

Subjects

Consecutive 44 patients (15 M, 29 F) with unilateral refractory LE.

Methods

All patients underwent detailed clinical, electrophysiological and ultrasonographic evaluations. Ultrasound imaging was used to evaluate thickness and presence of abnormal findings of the common extensor tendon (CET) and cross-sectional area (CSA) of the radial nerve (at spiral groove and before bifurcation) bilaterally. Unaffected sides of the patients were taken as controls.

Results

When compared with the unaffected sides, CET thickness and radial nerve CSAs (at both levels) were higher, and abnormal US findings regarding LE (47.7% vs. 6.8%) were more common on the affected sides than nonaffected sides (all P  < 0.001). Grip strength values were lower on the affected sides ( P  < 0.001). Electrophysiological studies were all normal, and similar between the two sides (all P  > 0.05). When subgroup analyses were performed after taking into account the hand dominance, affected and dominant sides were found to be the same in 31 and different in 13 patients. In subgroups, CETs and radial nerve CSAs at both levels were higher on the affected sides (all P  < 0.01).

Conclusions

Radial nerves and the CETs seem to be swollen on the affected sides, independent from the hand dominance of the patients with refractory LE. These results morphologically support the previous literature that attributes some of the chronic complaints of these patients actually to radial nerve entrapment.

Ultrasound-Guided Diagnosis and Treatment of Meralgia Paresthetica

Meralgia paresthetica refers to the entrapment of the lateral femoral cutaneous nerve at the level of the inguinal ligament. The lateral femoral cutaneous nerve – a purely sensory nerve – arises from the L2 and L3 spinal nerve roots, travels downward lateral to the psoas muscle, and then crosses the iliacus muscle. Close to the anterior superior iliac spine, the nerve courses in contact with the lateral aspect of the inguinal ligament and eventually innervates the lateral thigh. The entrapment syndrome is usually idiopathic but can also ensue due to trauma/ overuse, pelvic and retroperitoneal tumors, stretching of the nerve due to prolonged leg/trunk hyperextension, leg length discrepancies, prolonged standing, external compression by belts, weight gain, and tight clothing. The diagnosis of Meralgia paresthetica is usually clinical, i.e., based on the following symptoms: paresthesia, numbness, burning sensation, dysesthesia, and pain over the anterolateral aspects of the thigh. These complaints may be worsened by walking or prolonged standing and typically disappear after weight loss, abdominal muscle strengthening, or elimination of the underlying cause. Although there are several reports on the confirmatory role of electrodiagnostic studies in the diagnosis of Meralgia paresthetica, electromyographers would usually prefer/suggest not to perform nerve conduction studies in daily clinical practice. Herewith, due to its several advantages, ultrasound imaging has been proposed as an alternative diagnostic method in the recent literature. It not only confirms the entrapment morphologically, but also uncovers a likely underlying cause and provides immediate interventional guidance. The pertinent sonographic findings would be hypoechoic and swollen lateral femoral cutaneous nerve. Key words: Meralgia paresthetica, ultrasound, diagnosis, treatment

Ultrasound-Guided Diagnosis and Treatment of Meralgia Paresthetica

Meralgia paresthetica refers to the entrapment of the lateral femoral cutaneous nerve at the level of the inguinal ligament. The lateral femoral cutaneous nerve - a purely sensory nerve - arises from the L2 and L3 spinal nerve roots, travels downward lateral to the psoas muscle, and then crosses the iliacus muscle. Close to the anterior superior iliac spine, the nerve courses in contact with the lateral aspect of the inguinal ligament and eventually innervates the lateral thigh. The entrapment syndrome is usually idiopathic but can also ensue due to trauma/overuse, pelvic and retroperitoneal tumors, stretching of the nerve due to prolonged leg/trunk hyperextension, leg length discrepancies, prolonged standing, external compression by belts, weight gain, and tight clothing. The diagnosis of Meralgia paresthetica is usually clinical, i.e., based on the following symptoms: paresthesia, numbness, burning sensation, dysesthesia, and pain over the anterolateral aspects of the thigh. These complaints may be worsened by walking or prolonged standing and typically disappear after weight loss, abdominal muscle strengthening, or elimination of the underlying cause. Although there are several reports on the confirmatory role of electrodiagnostic studies in the diagnosis of Meralgia paresthetica, electromyographers would usually prefer/suggest not to perform nerve conduction studies in daily clinical practice. Herewith, due to its several advantages, ultrasound imaging has been proposed as an alternative diagnostic method in the recent literature. It not only confirms the entrapment morphologically, but also uncovers a likely underlying cause and provides immediate interventional guidance. The pertinent sonographic findings would be hypoechoic and swollen lateral femoral cutaneous nerve.

Ultrasound-Guided Diagnosis and Treatment of Morton’s Neuroma

Morton’s neuroma is the fibrous enlargement of the interdigital nerve branches, usually in the second and third interspace between the metatarsal heads where the lateral and medial plantar nerves often join. Specific symptoms are dull or sharp pain, numbness and/or tingling in the third and fourth digits, burning sensation, cramping, and a feeling of “walking on a stone” around the metatarsal heads. Numerous clinical tests for Morton’s neuroma have been described, such as thumb index finger squeeze, and Mulder’s click and foot squeeze tests. Ultrasound and magnetic resonance imaging can be used for confirmation, especially for differential diagnosis, exact localization, and number of neuromas. Further, performing dynamic imaging during the aforementioned tests is paramount and can readily be carried out with ultrasound. The treatment mainly comprises footwear modifications, radiofrequency ablation, physical therapy, local (corticosteroid and anesthetic) injections into the affected webspace, and surgery. Again the use of real-time ultrasound guidance during such interventions is noteworthy. Key words: Morton’s neuroma, ultrasound, diagnosis, treatment