Neurophysiological evaluation of bowel dysfunction in lower motor neuron lesions

Introduction: Fecal incontinence is a distressing condition, often caused by split of the anal sphincter or pelvic floor nerve injury. Constipation constituted additional bowel impairment in patients with neurogenic lesions. Patients suspected to have bowel dysfunction with neurogenic etiology should undergo neurophysiological testing. Aim of The work: This work was aimed to assess the electrodiagnostic value of sphincteric electromyography, pudendal nerve terminal motor latency, sacral reflexes, pudendal nerve and somatosensory-evoked potentials in bowel dysfunction. Patients and Methods: This study included 25 patients suffering from bowel dysfunction, with Lower motor neuron lesionsselected from Tanta and Alexandria University Hospitals. Diagnosis of the patients based on a full history including boweldysfunction and constipation questionnaires, complete physical and neurological examination andmagnetic resonance imaging.Followed by the electrodiagnostic of sphincteric electromyography, pudendal nerve terminal motor latency, sacral reflexes, and pudendal nerve somatosensory-evoked potentials. Results: The sensitivity of motor unit action potential of external anal sphincter parameters in diagnosis of neuropathic lesion include: sensitivity of amplitude 40% , duration 56 %, area 100%, , rise time 100%, phases 88%, denervation 56%.The sensitivity of other parameters in diagnosis of neuropathic lesion as following: bulbocavernosus12%, puborectalis56%, gracilis92%, pudendal nerve terminal motor latencies right 100% &left 88%, reflex the bulbocavernosus12%, ReflexPudendo-anal 72%, Somatosensory evoked potentials of pudendal nerve 28%.Conclusion:This study results point to the importance of using a combination of of motor unit action potentialparameters to increase sensitivity for the detection of neuropathic changes in bowel dysfunction