Author/Editor		Podnar, Simon
Title		Bilateral vs. unilateral electromyographic examination of the external anal sphincter muscle
Type		članek
Source		Neurophysiol Clin
Vol. and No.		Letnik 34
Publication year		2004
Volume		str. 153-7
Language		eng
Abstract		Aim of the study. - In patients with cauda equina or conus medullaris lesions, bilateral electromyographic (EMG) examination of the subcutaneous external anal sphincter (EAS) muscles has been suggested. In spite of its circular shape, EAS should be considered as two separate semicircular muscles. The aim of the present study was to test the hypothesis that information obtained by bilateral examination of the EAS muscle outweighs inconvenience due to additional needle insertions. Potients and mečhods. - A 8roup of 67 patients with clinical and radiological data supportive of cauda equina or conus meduLLaris lesion was studied. From the subcutaneous EAS muscles motor unit potentials (MUPs) were sampled by the standard concentric EMG needle electrode, and an advanced EMG system with template operated multi-MUP analysis. Severity of EMG abnormalities was determined, and compared in 48 pairs of the left/right subcutaneous EAS musdes. Results. - In 18 patients, bilateral EMG abnormalities were found, in five of them asymmetry of involvement was demonstrated. UniLateral MUP abnormalities were found in 22 patients. The sensitivity of unilateral EMG analysis was 57% and of bilateral examination, 83%. Conclusion. - In patients with suspected cauda equina Lesions, as a rule, bilateral EMG of the subcutaneous EAS muscle is recommended.
Descriptors		CAUDA EQUINA NERVE COMPRESSION SYNDROMES SPINAL CORD COMPRESSION ELECTROMYOGRAPHY ANUS MOTOR NEURONS