Comparison of the Spinal Level Assumption by Palpation of the Iliac Crest and Posterior Superior Iliac Spine

OBJECTIVE: To compare the clinical usefulness of the posterior superior iliac spine (PSIS) with that of iliac crest (IC) for identifying the lumbar vertebral level. METHOD: Lumbar spine level was identified by the line connecting bilateral upper margin of iliac crests in the antero-posterior lumbar X-rays of 120 patients. Assumed IC level and assumed PSIS level were compared by 3 examiners' palpation in 60 patients. A marker was taped on assumed IC level and assumed PSIS level by 4 examiners and the postero-anterior lumbar X-rays was taken in randomly distributed 50 patients. RESULTS: IC intersection line was ranged from the L4 spinous process to the L5-S1 interspinous process in all patients. Inter- examiner agreement of palpation was significantly greater in PSIS than IC level (p<0.05). The marker indicating assumed IC level was higher than true IC level in all patients and was higher than L3-4 interspinous process in 8%. CONCLUSION: We may use PSIS level for assumption of the lumbar vertebral level to compensate for the limitation of iliac crest palpation, but at the same time keep in the mind the variarity of the PSIS level.

Clinical Significance of the R3 Response of the Blink Reflex in Medullar and Cervical Spinal Cord Lesions

OBJECTIVE: To compare the R3 response of the blink reflex in medullar and spinal cord lesion and to investigate whether the reflex arc of the R3 response descend to the cervical spinal cord or not. METHOD: We have studied 3 patients with medullar lesion and 5 patients with cervical spinal cord or vertebral lesion. Normal ranges of the R3 response refer to the results suggested by Moon et al. RESULTS: In 3 patients with medullar lesion, two patients with lateral medullar lesion showed delayed R3 latency or no evoked potential. Four patients with cervial spinal cord lesion showed no R3 response. In one patient with disc protrusion R3 was normal. CONCLUSION: Our results support the hypothesis that the reflex arc of the R3 response descend to the cervical spinal cord.

Lateral Femoral Cutaneous Nerve Conduction Study

OBJECTIVE: The purpose of this study was to determine the reliability and usefulness of the lateral femoral cutaneous nerve conduction study by comparing the modified Ma's method (method I) with the method proposed by Spevak and Prevec (method II) and to develop a standard value of the Korean normal adult by the method II. METHOD: Twenty-nine healthy adults were examined for the lateral femoral cutaneous nerve conduction by both methods bilaterally. The nerve was stimulated 1 cm medial to anterior superior iliac spine (ASIS) in the method I and 8 cm distal to ASIS in the method II. The sensory nerve action potential was recorded with 8 cm long strip electrodes placed on the thigh 17 cm distal to ASIS in the method I and 33 cm distal to ASIS in the method II. RESULTS: 1) Among 58 extremities, a sensory nerve action potential was detected in 52 extremities (89.7%) by the method I and in 57 extremities (98.3%) by the method II without a significant difference between both methods. 2) The mean distal latency was 3.41 msec by the method I and 4.56 msec by the method II. 3) The mean amplitude was 7.24 microvolt by the method I and 6.63 microvolt by the method II without a significant difference between both methods. 4) The mean conduction velocity was 50.9 m/sec by the method I and 55.2 m/sec by the method II without a significant difference between both methods. CONCLUSION: According to the study, both methods are compatible and reliable for the examination of lateral femoral cutaneous nerve except for a significant difference in a mean conduction velocity.