Seung Nam Yang

Needle Electrode Insertion Into the Tibialis Posterior: A Comparison of the Anterior and Posterior Approaches

OBJECTIVES To analyze and compare the safety of the anterior and posterior approaches for needle electrode placement and to examine the method for inserting the needle electrode using the anterior approach. DESIGN Cross-sectional study. SETTING University hospital. PARTICIPANTS Lower-extremity radiographs and magnetic resonance images of 22 patients (13 men, 9 women). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURE Measurement of lower-extremity radiographs and magnetic resonance imaging. RESULTS The anterior approach offers the advantage of a larger safe window for needle insertion into the upper third of the leg than the posterior approach. No significant differences were observed between the anterior and posterior approaches in terms of safety of needle insertion into the midpoint. The safe zone of the overlying skin for needle insertion was found to be approximately 40% to 80% of the width of the tibia away from the lateral margin of the tibia shaft on the upper third of the leg and 32% to 58% of the width of the tibia at the midpoint of the leg in the anterior approach. CONCLUSIONS The method suggested in this article can be used for needle electromyography and deserves more widespread use in clinical practice.

Sonographic features of peripheral nerves at multiple sites in patients with diabetic polyneuropathy

OBJECTIVE Diabetic polyneuropathy (DPN) is one of the major complications of diabetes mellitus. Ultrasound has been frequently used for evaluation of peripheral nerves. However, there are few studies that have evaluated multiple peripheral nerves in DPN. In this study, ultrasonographic features of multiple peripheral nerves in upper and lower extremities of DPN patients were investigated and compared with those of healthy controls. METHODS This study was a case-control study that enrolled 20 patients with confirmed diagnosis of DPN and 20 healthy controls. The ultrasonography was performed on the sural, tibial, fibular, sciatic, median, ulnar, radial, and musculocutaneous nerves. Nerve cross-sectional area (CSA) was measured at multiple points for each peripheral nerve. The CSAs were compared between DPN and control groups, and analyzed in relation to the clinical characteristics and electrophysiologic findings. RESULTS The CSAs were significantly larger in the DPN group for sural nerve, fibular nerve at the fibular head level, median nerve at the carpal tunnel and mid-humerus level, ulnar nerve at the cubital tunnel outlet and mid-humerus level, and radial nerve at the spiral groove. The CSAs of sural nerve, tibial nerve and median nerve were significantly correlated with electrophysiologic findings. The sural nerve CSA revealed significant correlation with HbA1c. CONCLUSIONS These results suggest that the ultrasonography can provide useful information in diagnosis and evaluation of DPN.

Movement of the ulnar nerve at the elbow: A sonographic study

The aim of this study was to measure the degree of movement of the ulnar nerve in the cubital tunnel using sonography in patients with ulnar neuropathy at the elbow compared to a healthy control group.

Muscular polyarteritis nodosa.

We present an unusual case of a 26-year-old man with muscular polyarteritis nodosa (PAN) with severe calf pain and gait disturbance. Magnetic resonance imaging of the lower limbs demonstrated highly increased signal intensity in both soleus muscles and the lateral head of the left gastrocnemius muscle. Biopsies of the soleus muscle showed acute necrotizing arteritis. The calf pain and limited range of motion of ankle dorsiflexion subsided from day 1 on administration of oral corticosteroid at high dosage and were completely resolved by 4 months. After tapering corticosteroid to 10 mg, symptoms recurred. A combined regimen of immunosuppressants was found to maintain symptomatic relief.Muscular PAN should be included in the differential diagnosis of a patient presenting with symptoms of acute or subacute calf pain. Although this muscular PAN was so far been benign, complete remission of the underlying process may be difficult to achieve.

L1 radiculopathy mimicking meralgia paresthetica: A case report

L1 radiculopathy is very rare and difficult to diagnose with needle electromyography. A patient presented with pain and hypesthesia on the anterolateral aspect of the left thigh. Nerve conduction studies and needle electromyography were normal, except for the quadratus lumborum and iliopsoas muscles, which showed abnormal spontaneous activity and polyphasic motor unit potentials with reduced recruitment patterns. Magnetic resonance imaging of the lumbar spine showed disc extrusion of the L1–2 intervertebral space with upward migration. This case demonstrates the usefulness of examination of the quadratus lumborum in the diagnosis of L1 radiculopathy. Muscle Nerve 41: 566–568, 2010

Factors Affecting the Motor Evoked Potential Responsiveness and Parameters in Patients With Supratentorial Stroke

Objective To investigate the factors which affect the motor evoked potential (MEP) responsiveness and parameters and to find the correlation between the function of the upper extremities and the combined study of MEP with a diffusion tensor tractography (DTT) in patients with stroke. Methods A retrospective study design was used by analyzing medical records and neuroimaging data of 70 stroke patients who underwent a MEP test between June 2011 and March 2013. MEP parameters which were recorded from the abductor pollicis brevis muscle were the resting motor threshold, latency, amplitude, and their ratios. Functional variables, Brunnstrom stage of hand, upper extremity subscore of Fugl-Meyer assessment, Manual Function Test, and the Korean version of Modified Barthel Index (K-MBI) were collected together with the biographical and neurological data. The DTT parameters were fiber number, fractional anisotropy value and their ratios of affected corticospinal tract. The data were compared between two groups, built up according to the presence (MEP-P) or absence (MEP-N) of MEP on the affected hand. Results Functional and DTT variables were significantly different between MEP-P and MEP-N groups (p<0.001). Among the MEP-P group, the amplitude ratio (unaffected/affected) was significantly correlated with the Brunnstrom stage of hand (r=-0.427, p=0.013), K-MBI (r=-0.380, p=0.029) and the time post-onset (r=-0.401, p=0.021). The functional scores were significantly better when both MEP response and DTT were present and decreased if one or both of the two studies were absent. Conclusion This study indicates MEP responsiveness and amplitude ratio are significantly associated with the upper extremity function and the activities of daily living performance, and the combined study of MEP and DTT provides useful information.

Lofgren's Syndrome-Acute Onset Sarcoidosis and Polyarthralgia: A Case Report.

Lofgrens syndrome is an acute form of sarcoidosis characterized by erythema nodosum, bilateral hilar lymphadenopathy (BHL), and polyarthralgia or polyarthritis. This syndrome is common among Caucasians but rare in the Korean population. A 44-year-old woman was admitted to our hospital complaining of polyarthralgia. A chest radiograph revealed BHL and nodular shadows. Angiotensin-converting enzyme levels were within the normal range. Tissue biopsy from a mediastinum lymph node showed noncaseating granulomas. We diagnosed her with Lofgrens syndrome, an acute form of sarcoidosis.

Ultrasound-Guided Lateral Femoral Cutaneous Nerve Conduction Study

Objective To verify the utility of the lateral femoral cutaneous nerve (LFCN) ultrasound-guided conduction technique compared to that of the conventional nerve conduction technique. Methods Fifty-eight legs of 29 healthy participants (18 males and 11 females; mean age, 42.7±14.9 years) were recruited. The conventional technique was performed bilaterally. The LFCN was localized by ultrasound. Cross-sectional area (CSA) of the LFCN and the distance between the anterior superior iliac spine (ASIS) and the LFCN was measured. The nerve conduction study was repeated with the corrected cathode location. Sensory nerve action potential (SNAP) amplitudes of the LFCN were recorded and compared between the ultrasound-guided and conventional techniques. Results Mean body mass index of the participants was 23.7±3.5 kg/m2, CSA was 4.2±1.9 mm2, and the distance between the ASIS and LFCN was 5.6±1.7 mm. The mean amplitude values were 6.07±0.52 µV and 6.66±0.54 µV using the conventional and ultrasound-guided techniques, respectively. The SNAP amplitude of the LFCN using the ultrasound-guided technique was significantly larger than that recorded using the conventional technique. Conclusion Correcting the stimulation position using the ultrasound-guided technique helped obtain increased SNAP amplitude.

Is median nerve enlargement at the wrist associated with tremor in Parkinson disease

Tremor is one of the cardinal features of Parkinson disease (PD) and may cause cumulative trauma‐related injury to nerves of the hands. The aim of this study was to assess the electrodiagnostic and sonographic features of patients with PD and to assess the effect of tremor in PD on the median nerve.

Sonographic Evaluation of the Peripheral Nerves in Hereditary Neuropathy With Liability to Pressure Palsies: A Case Report

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominantly inherited disorder that affects peripheral nerves by repeated focal pressure. HNPP can be diagnosed by clinical findings, electrodiagnostic studies, histopathological features, and genetic analysis. Ultrasonography is increasingly used for the diagnosis of neuromuscular diseases; however, sonographic features of HNPP have not been clearly defined. We report the sonographic findings and comparative electrodiagnostic data in a 73-year-old woman with HNPP, confirmed by genetic analysis. The cross-sectional areas of peripheral nerves were enlarged at typical nerve entrapment sites, but enlargement at non-entrapment sites was uncommon. These sonographic features may be helpful for diagnosis of HNPP when electrodiagnostic studies are suspicious of HNPP and/or gene study is not compatible.