A 34-year-old man complained of repeated anal mass prolapse with occasional bleeding for five years. The anal mass prolapse after defecation and bleeding was usually bright red and not mixed with the stool. Since the anal mass was exacerbated, he was no longer able to bear the mass and bleeding. The patient received rectosigmoidoscopy and was diagnosed with hemorrhoids. His laboratory work, including routine blood work, electrolyte tests, and hepatic, renal, and coagulation functions, was within the normal range. After completing the preoperative preparation, the patient was sent to the operating room. The L3/4 intervertebral space was chosen as the puncture point. Cerebrospinal fluid could be seen when the needle is inserted 4 cm. One milliliter of 1% ropivacaine hydrochloride injection (Naropin) mixed with saline solution (0.9 ml) was slowly injected into the subarachnoid space in approximately 20 s. At the same time, an epidural catheter was inserted 8 cm in the L3/4 intervertebral space. After approximately 10 min, anesthesia took effect, and the blocked level of the sensory system was raised and fixed at the T8 level. The duration of PPH operation was 50 min, and the patient had no discomfort during the anesthesia time and operation time. A patient-controlled epidural analgesia (PCEA) was connected to the epidural catheter. The 100 ml PCEA solution consisted of 2 ml sufentanil citrate injection (YICHANG HUMANWEL PHARMACETICAL, 100 µg/2 ml/bnp), 238.4 mg ropivacaine mesylate injection (PUDE PHARMA, 119.2 mg/bnp) and 98 ml saline solution. The PCEA could last 2 days with a constant injection speed of 2 ml/h. The patient also needed an indwelling urinary catheter for 2 days since he was not able to urinate himself when the PCEA was at work. However, 2 days later, when we tried to remove the catheter, he was still not able to urinate. At first, we thought it was because of pain, since urinary retention is a common complication of CSEA or PPH. We then administered one celecoxib capsule and one tamsulosin hydrochloride sustained-release capsule per day. After 5 days, the patient tried to remove the catheter the second time, but he still could not urinate and had difficulty defecating with occasional urinary incontinence, and he developed lower abdomen and back pain. This time, levofloxacin hydrochloride tablets and San Jin Pian tablets, were added to his medication list with one and three pills, respectively, administered twice a day. Lactulose oral solution was used to help soften stools. However, his symptoms did not significantly improve. Further tests were performed on the patient. Electromyography showed no abnormal motor or sensory nerve conduction in the lower limbs, but lower extremity somatosensory evoked potentials P37 and N45 were not elicited. In addition, urodynamic testing found that the detrusor muscle of his bladder had no contractile force. Uroflowmetry could not be measured, and when abdominal pressure assisted urination, the bladder did not contract. Lumbar magnetic resonance imaging showed that there was a 1.79 cm*1.66 cm*1.91 cm Tarlov cyst at the left S1 level in the sacral canal. Although lumbar MRI data showed that the cyst did not compress the lower spinal cord or cauda equine, we still considered that this patient had mild CES. Based the results, we changed his medications and one methylcobalamin tablet and one flupentixol/melitracen tablet was administered three times and once per day, respectively, to promote nerve growth and relieve tension. Finally, the fourth time we removed the catheter, he was able to urinate by himself after 5 days. We reviewed him a month later and his urinary retention had completely gone, and his bowel habits had returned to normal. We also performed a sacral ultrasound on the patient, since the cyst was just at the S1 level and might be detected through the intervertebral space at L5/S1 or posterior sacral foramina at S1. However, unfortunately, we could not find the cyst under ultrasound.