OBJECTIVE: To identify the center of extensor indicis (EI) muscle through cadaver dissection and compare the accuracy of different techniques for needle electromyography (EMG) electrode insertion. METHODS: Eighteen upper limbs of 10 adult cadavers were dissected. The center of trigonal EI muscle was defined as the point where the three medians of the triangle intersect. Three different needle electrode insertion techniques were introduced: M1, 2.5 cm above the lower border of ulnar styloid process (USP), lateral aspect of the ulna; M2, 2 finger breadths (FB) proximal to USP, lateral aspect of the ulna; and M3, distal fourth of the forearm, lateral aspect of the ulna. The distance from USP to the center (X) parallel to the line between radial head to USP, and from medial border of ulna to the center (Y) were measured. The distances between 3 different points (M1– M3) and the center were measured (marked as D1, D2, and D3, respectively). RESULTS: The median value of X was 48.3 mm and that of Y was 7.2 mm. The median values of D1, D2 and D3 were 23.3 mm, 13.3 mm and 9.0 mm, respectively. CONCLUSION: The center of EI muscle is located approximately 4.8 cm proximal to USP level and 7.2 mm lateral to the medial border of the ulna. Among the three methods, the technique placing the needle electrode at distal fourth of the forearm and lateral to the radial side of the ulna bone (M3) is the most accurate and closest to the center of the EI muscle.
Adult ; Cadaver* ; Electrodes ; Electrodiagnosis ; Electromyography* ; Fingers ; Forearm ; Head ; Humans ; Needles* ; Ulna ; Upper Extremity

OBJECTIVE: To compare the diagnostic significance of H reflex and somatosensory evoked potential(SEP) in the diagnosis of S1 radiculopathy, and to explore the possible interpretations on the discrepancies of the test results. METHOD: Twenty-eight patients who were diagnosed as a S1 radiculopathy by the clinical and radiological correlations, and thirty-five controls with no evidence of S1 radiculopathy by the clinical or radiological studies were studied by the H reflex, sural SEP, and needle electromyography. RESULTS: The sensitivity of H reflex study was 64% for the S1 radiculopathy, and the specificity was 86%. The sensitivity and the specificity of the sural SEP study for the S1 radiculopathy were 50% and 80% respectively. Within 1 month from the onset, the sensitivity of H reflex increased to 75%. The needle electromyography showed 19% for the sensitivity and 100% for the specificity. The probability of the S1 radiculopathy was 70% in 10 cases who had the abnormal H reflex and normal SEP values and 36% in 8 cases who had the normal H reflex and abnormal SEP values. CONCLUSION: H reflex study was the most sensitive test in the electrodiagnosis of the S1 radiculopathy and the electrodiagnostic significance of sural SEP was obscure.
Diagnosis ; Electrodiagnosis ; Electromyography ; Evoked Potentials, Somatosensory* ; H-Reflex* ; Humans ; Needles ; Radiculopathy* ; Sensitivity and Specificity

OBJECTIVE: To reveal the pattern of involvement of the peroneal and tibial division in the sciatic nerve injury according to the locations and etiologies. METHOD: Fifty-four patients with sciatic nerve injuries were investigated. The relative involvement of peroneal dominant (PD) and tibial dominant (TD) were determined by needle electromyography, and the locations and etiologies of sciatic nerve injury were evaluated. Fifteen patients were followed up and the prognostic factors were investigated. RESULTS: The peroneal division was more severely affected in thirty-three cases (59.3%), tibial division was more in thirteen cases (24.1%), and there were nine cases (16.7%) equally affected. Fracture was the most common cause of sciatic nerve injury, and TD was common in case of pelvic fracture while PD was common in the lesions below the hip joint. Younger person, responsiveness of sensory nerve conduction and fracture were the factors of better improvement while pattern of involvement (TD/PD) was not. CONCLUSION: The sciatic nerve injuries affected the peroneal division greater than the tibial division, but in case of pelvic fracture it affected the tibial division greater than the peroneal division. The relative fixation and anatomical difference of peroneal nerve was thought to be the cause of those differences.
Electrodiagnosis ; Electromyography ; Hip Joint ; Humans ; Needles ; Neural Conduction ; Peroneal Nerve ; Sciatic Nerve*

OBJECTIVE: To investigate the relationship the electrodiagnostic findings with the functional outcomes in spina bifida patients and to assess usefulness of follow up electrodiagnostic study. METHOD: Initial and follow up electrodiagnostic data of 100 patients who had been diagnosed as spina bifida were obtained retrospectively. Electrophysiological diagnosis and neurological level were investigated by the findings of needle electromyography. Each patients were divided into no change, improvement and deterioration group according to follow up study. The change of urodynamic study findings and clinical findings were also investigated. The recent functional outcomes and the presence of complications were evaluated by recent outpatient record. RESULTS: 56 patients had no change, 15 patients had improvement and 29 patients had deterioration electrophysiologically. The initial electrodiagnostic findings were associated with the functional outcomes in patients with spina bifida (p<0.05). However, neurological level by electrodiagnostic findings cannot predict functional outcomes except ambulation activities. The change of electrodiagnostic findings of follow up study were related with the change of clinical findings statistically (p<0.05). CONCLUSION: Follow up electrodiagnostic study as well as initial study is necessary for the evaluation of the change of neurological states in the patients with spina bifida.
Diagnosis ; Electrodiagnosis ; Electromyography ; Follow-Up Studies ; Humans ; Needles ; Outpatients ; Retrospective Studies ; Spinal Dysraphism ; Urodynamics ; Walking

OBJECTIVE: To investigate the usefulness of the somatosensory evoked potentials (SEP) study in predicting the outcome of complete peripheral nerve injury. METHOD: Thirty eight complete peripheral nerve injuries, diagnosed by motor and sensory nerve conduction studies (NCS) and needle electromyography (nEMG), were studied. Nerve injuries were grouped into two groups with and without SEP recorded at the time of initial evaluation. Outcome of nerve injuries was graded from 0 to 3 based on the results of NCSs and nEMG, followed up for more than six months. Grade 0 was designated for those with no evidence of recovery, and grade 3 for those with recovery in nEMG and both motor and sensory NCSs. RESULTS: At the time of initial electrodiagnosis, SEP study showed no response in 25 cases, but SEP could be observed in 13 cases, although they were attenuated or delayed. Recovery of nerve injury was observed in 22 cases, despite the findings compatible with complete injury in initial NCSs and nEMG. The group in which SEPs were recorded showed significantly higher grades of recovery, compared to no response group. CONCLUSION: In predicting the prognosis of complete peripheral nerve injuries, SEP study could be useful as a supplementary electrodiagnostic method.
Electrodiagnosis ; Electromyography ; Evoked Potentials, Somatosensory* ; Needles ; Neural Conduction ; Peripheral Nerve Injuries* ; Peripheral Nerves* ; Prognosis*

Assessment of peripheral nerve injury is a common task in forensic practice. As an objective assistance of inspection, electrophysiological examination is significant in the evaluation of peripheral nerve function after injury. There are currently several methods of electrophysiological examination, including I-T curve, EMG, NCV and SEP. Because electrophysiological examination can assess the injury and regeneration of peripheral nerve injury at different times, it is valuable to estimate prognosis of peripheral nerve injury in forensic medicine. Besides the electrophysiological examination, evaluation of the peripheral nerve injury needs to combine other clinical manifestations to provide an accurate appraisal.
Electrodiagnosis/methods* ; Electromyography/methods* ; Forensic Medicine ; Humans ; Neural Conduction/physiology* ; Peripheral Nerve Injuries ; Peripheral Nerves/physiopathology*

OBJECTIVE: To investigate the contributing factors of carpal tunnel syndrome (CTS), electrodiagnostic and ultrasonographic findings of median nerve, and median nerve change after exercise in wheelchair basketball (WCB) players. METHODS: Fifteen WCB players with manual wheelchairs were enrolled in the study. Medical history of the subjects was taken. Electrodiagnosis and ultrasonography of both median nerves were performed to assess CTS in WCB players. Ultrasonographic median nerves evaluation was conducted after wheelchair propulsion for 20 minutes. RESULTS: Average body mass index (BMI) and period of wheelchair use of CTS subjects were greater than those of normal subjects. Electrodiagnosis revealed CTS in 14 of 30 hands (47%). Cross-sectional area (CSA) of median nerve was greater in CTS subjects than in normal subjects at 0.5 cm and 1 cm proximal to distal wrist crease (DWC), DWC, 1 cm, 2 cm, 3 cm, and 3.5 cm distal to DWC. After exercising, median nerve CSAs at 0.5 cm and 1 cm proximal to DWC, DWC, and 3 cm and 3.5 cm distal to DWC were greater than baseline CSAs in CTS subjects; and median nerve CSAs at 1 cm proximal to DWC and DWC were greater than baseline CSAs in normal subjects. The changes in median nerve CSA after exercise in CTS subjects were greater than in normal subjects at 0.5 cm proximal to DWC and 3 cm and 3.5 cm distal to DWC. CONCLUSION: BMI and total period of wheelchair use contributed to developing CTS in WCB players. The experimental exercise might be related to the median nerve swelling around the inlet and outlet of carpal tunnel in WCB athletes with CTS.
Athletes* ; Basketball* ; Bays ; Body Mass Index ; Carpal Tunnel Syndrome* ; Electrodiagnosis ; Electromyography ; Hand ; Humans ; Median Nerve ; Ultrasonography ; Wheelchairs* ; Wrist

OBJECTIVE: To evaluate the relationship between postoperative sensory change on lower extremities and clinical factors associated with gynecologic operation. METHODS: We retrospectively reviewed 38 cases of patients with postoperative complaints of pain or dysthesis on lower extremities, especially anterolateral thigh from March 1993 through December 1999 at Gyeongsang National University Hospital, Department of Obstetrics and Gynecology. The electromyography (EMG) and nerve conduction velocity (NCV) were performed in all 38 patients. According to the result of EMG and NCV, patients were divided into control group (n=28) which in that with normal finding in electrodiagnosis and study group (n=10) who showed femoral cutaneous nerve injury in electrodiagnosis. Clinical characteristics (age, height, weight and operative history), operative methods, skin incisional method, operative time and postoperative diagnosis were reviewed in each group. RESULTS: There were significant differences in patient's body weight, height, skin incisional method and operative method between control and study group. Height was 152.5cm [150.3-155.6] in study group and 157.5cm [153.4-159.2] in control group (p-value = 0.020). Weight was 46.9kg [43.4-58.0] in study group and 57.0kg [54.4-58.1] in control group (p-value=0.004). Skin incisional method in study group was done by 6 cases (60%) of infraumbilical mid-line vertical incision and in control group by 5 cases (17.9%) (p-value = 0.019). In operative method, radical hysterectomy was 4 cases (40%) in study group and 2 cases (7.1%) in control group (p-value=0.031). But no correlation was observed in post-operative diagnosis, operative time, blood loss and transfusion between two groups. CONCLUSION: It was suggested that Lateral femoral cutaneous nerve was compressed by pelvic retractor during the gynecologic operation. Patient's body weight, height, skin incisional method and operative method may play a role of compressive factor on Lateral femoral cutaneous nerve, increasing Meralgia Paresthetica.
Body Weight ; Diagnosis ; Electrodiagnosis ; Electromyography ; Gynecology ; Humans ; Hysterectomy ; Lower Extremity ; Neural Conduction ; Obstetrics ; Operative Time ; Retrospective Studies ; Skin ; Thigh

OBJECTIVE: To evaluate the clinical significance of motor unit number estimation (MUNE) and quantitative analysis of motor unit action potential (MUAP) in carpal tunnel syndrome (CTS) according to electrophysiologic severity, ultrasonographic measurement and clinical symptoms. METHOD: We evaluated 78 wrists of 45 patients, who had been diagnosed with CTS and 42 wrists of 21 healthy controls. Median nerve conduction studies, amplitude and duration of MUAP, and the MUNE of the abductor pollicis brevis were measured. The cross sectional area (CSA) of the median nerve at the pisiform and distal radioulnar joint level was determined by high resolution ultrasonography. Clinical symptom of CTS was assessed using the Boston Carpal Tunnel Questionnaire (BCTQ). RESULTS: The MUNE, the amplitude and the duration of MUAP of the CTS group were significantly different from those found in the control group. The area under the ROC curve was 0.944 for MUNE, 0.923 for MUAP amplitude and 0.953 for MUAP duration. MUNE had a negative correlation with electrophysiologic stage of CTS, amplitude and duration of MUAP, CSA at pisiform level, and the score of BCTQ. The amplitude and duration of MUAP had a positive correlation with the score of BCTQ. The electrophysiologic stage was correlated with amplitude but not with the duration of MUAP. CONCLUSION: MUNE, amplitude and duration of MUAP are useful tests for diagnosis of CTS. In addition, the MUNE serves as a good indicator of CTS severity.
Action Potentials ; Boston ; Carpal Tunnel Syndrome ; Electrodiagnosis ; Electromyography ; Humans ; Joints ; Median Nerve ; ROC Curve ; Wrist ; Surveys and Questionnaires

OBJECTIVE: This study was to evaluate the correlation of clinical symptoms and physical signs with electrodiagnostic findings in carpal tunnel syndrome (CTS), and to increase the usefulness of clinical symptoms and physical signs in the diagnosis of CTS. METHOD: We prospectively identified 322 hands from 172 subjects clinically from 5 tertiary hospitals. All subjects completed 6 clinical symptoms and 6 physical signs including 3 provocative tests. Each symptoms and signs were divided motor and sensory symptoms and signs, and the correlation between symptoms and signs and the results of motor and sensory conduction studies and needle electromyography were evaluated. The sensitivity and specificity of each valuable symptoms and signs for electrodiagnostic results were also assessed. RESULTS: Tingling sensation, nocturnal pain, worsening, and Phalen sign were correlated with motor conduction study, and falling tendency, abductor pollicis brevis weakness and atrophy, tingling sensation, hypoesthesia, and Tinel and Phalen signs were correlated with needle electromyography. The Phalen sign had the best sensitivity and specificity for median motor conduction study, and the best sensitive physical sign for needle electromyography. CONCLUSION: Motor and sensory symptoms and signs were not correlated with motor and sensory conduction studies, but motor symptoms and signs were correlated with needle electromyography. The Phalen test was the most useful evaluating tool to diagnose CTS.
Atrophy ; Carpal Tunnel Syndrome* ; Diagnosis ; Electrodiagnosis ; Electromyography ; Hand ; Hypesthesia ; Needles ; Prospective Studies ; Sensation ; Sensitivity and Specificity ; Tertiary Care Centers