S. Podnar () Institute of Clinical Neurophysiology Division of Neurology University Medical Center Ljubljana SI–1525 Ljubljana, Slovenia E-mail: simon.podnar@kclj.si rophysiology is discouraged. In patients with suspected neu- rogenic bowel disorders, comprehensive electrodiagnostic approach, performed by clinical neurophysiologists experi- enced in application of these tests to the sacral nervous sys- tem, should complement data obtained by other methods and giude patient management. Key words Anal incontinence • Constipation • Electro- diagnosis • External anal sphincter • Needle electromyogra- phy • Pelvic floor Introduction In many patients with anal incontinence and constipation, the clinician can make a reasonably accurate diagnosis after completing the medical history and clinical examination. However, to obtain the diagnosis and determine the optimal treatment in a proportion of patients, instrumental investiga- tions (imaging, manometry, endoscopy, electrodiagnosis) are needed. Electrodiagnostic techniques should be considered in patients with a suspected neurogenic etiology of their bowel dysfunction [1, 2]. Neurogenic versus non-neurogenic bowel dysfunction On assessing a patient with possible neurogenic bowel dys- function, the crucial question is the probability of such etiol- ogy. The patient’s medical history is very important in this regard. Neurogenic bowel dysfunction usually occurs con- comitantly with other sacral (urinary and sexual) dysfunc- tion, meaning that their concomitant occurrence will increase the probability of a neurogenic etiology [3]. Furthermore, it is important to inquire about neurological diagnoses with common bowel dysfunction, such as a spinal cord lesion, Tech Coloproctol (2003) 7:71–76 DOI 10.1007/s10151-003-0012-x © Springer-Verlag 2003 S. Podnar Electrodiagnosis of the anorectum: a review of techniques and clinical applications Received: 20 December 2002 / Accepted: 17 March 2003 REVIEW Abstract Electrodiagnostic tests may be valuable in the assessment of patients with anorectal dysfunction and are complementary to imaging and manometry. While the latter delineate morphological and functional sphincter changes, respectively, electrodiagnostic methods document, help to localize and assess the severity and mechanism of neural injury. These data are important for the treatment of patients and for estimating their prognoses. Among electrodiagnostic tests, concentric needle electromyography of the external anal sphincter is the most important. It demonstrates muscle denervation, quantitatively estimates muscle reinnervation, estimates the level of motor neuron excitability and assess- es several kinesiological parameters. In addition, measure- ment of the bulbocavernosus reflex is often useful, while pudendal somatosensory evoked potentials are sometimes useful. Use of single tests of sacral nervous system by work- ers less familiar with theoretical principles of clinical neu- Presented in part at the Meeting of the Mediterranean Society of Coloproctology, Otoćec, Slovenia, September 2002.