Sacral plexus disorder caused by a wooden toothpick in the rectum

A 67-year-old man presented with a 2-month history of pain in his right buttock and lower limb. MRI depicted right L5/S1 lateral recess stenosis requiring surgical treatment; however, preoperative CT showed an approximately 7 cm long, thin, rod-shaped structure in the rectum, which was ultimately determined to be an accidentally ingested toothpick. It was removed surgically 6 days after diagnosis, because right leg pain worsened rapidly. The pain disappeared thereafter, and the symptoms have not recurred since. The pain might have been localised to the right buttock and posterior thigh in the early stages because the fine tip of the toothpick was positioned to the right of the anterior ramus of the S2 spinal nerve. Although sacral plexus disorder caused by a rectal foreign body is extremely rare, physicians should be mindful to avoid misdiagnosis.