Bulbocavernosus reflex and pudendal nerve somatosensory evoked potential are valuable for the diagnosis of cauda equina syndrome in male patients.

Aims: This study is to assess the value of bulbocavernosus reflex (BCR) and pudendal nerve somatosensory evoked potential (SSEP) in the topical diagnosis of cauda equina syndrome (CES) with or without sphincter dysfunction in male patients. Methods: In this study, 40 healthy male adults (control group) and 53 male adult patients (experimental group) were included. The experimental group was subdivided into sphincter subgroup (24 patients with sphincter dysfunction) and non-sphincter subgroup (29 patients without sphincter dysfunction). All subjects underwent BCR and SSEP examinations. The mean latencies of BCR and SSEP P41 were calculated and compared between the control group and the experimental group. Latencies above the average value of +2.58S were considered abnormal. The abnormality rates of BCRs and SSEPs in sphincter and non-sphincter subgroups were calculated, respectively. Results: BCR and SSEP latencies in the experimental group were remarkably prolonged than those in the control group. BCR and SSEP latencies in sphincter subgroup were remarkably prolonged than those in non-sphincter subgroup. Among the 106 nerves in the experimental group, 87 nerves had prolonged BCR latencies and 3 nerves had no wave elicited, with an abnormality rate of 84.9%. The abnormality rates of BCR were 95.8% and 74.1% in sphincter subgroup and non-sphincter subgroup, respectively. Among the 53 nerves in the experimental group, 39 nerves had prolonged SSEP P41 latencies and 2 nerves had no wave elicited, with an abnormality rate of 77.4%. The abnormality rates of SSEP P41 were 91.7% and 65.5% in sphincter subgroup and non-sphincter subgroup, respectively. Conclusions: Both BCR and SSEP were changed in CES patients with or without sphincter dysfunction, and they were especially changed in patients with sphincter dysfunction. BCR and SSEP are valuable in the diagnosis of cauda equina lesions and their severity in males.