Intrathecal Hydromorphone for Postoperative Pain of Anorectal Surgery

Intrathecal Hydromorphone for Postoperative Pain of Anorectal Surgery: A Randomized, Double-blind, Parallel, Placebo-controlled Trial

Anorectal problems, such as hemorrhoids, fistula, fissures, Etc., often require surgical treatment. Patients often have postoperative pain after these surgeries, which increases discomfort and hospital length of stay. The efficacy of oral non-opioids in the treatment of such pain is poor. Hydromorphone is an opioid analgesic commonly used orally or intravenously for postoperative pain management. We designed this trial to investigate the efficacy and safety of intrathecal (delivery directly to the spinal cord during spinal anesthesia) single dose hydromorphone versus intrathecal placebo in treating postoperative pain among human subjects after anorectal surgery, but also the recovery of postoperative motor capacity in these human subjects.

Inclusion Criteria:

• 1. Clinical Diagnosis of anorectal disease, ready to undergo elective surgery
• 2. American Society of Anesthesiologists(ASA) physical status I-II
• 3. Desire to have a spinal anesthesia
• 4. Must be able to follow the medication dose and visit schedule

Exclusion Criteria:

• 1. Any contraindications to spinal anesthesia and intrathecal analgesia.

• 2. Complex co-morbidities, including

  1. Severe infection,
  2. Respiratory insufficiency,
  3. History of psychiatric or neurological disorders and other cognitive impairments

• 3. Chronic pain syndrome or current opioid use >10mg oral morphine equivalents/day

• 4. Allergy or intolerance to hydromorphone, NSAIDs and Cox-2 selective Inhibitor

• 5. Clinical diagnosis of obstructive sleep apnea syndrome(OSAS)

• 6. History of drug abuse

• 7. Women who are breastfeeding or pregnant

• 8. Participation in other clinical trials within three months

• 9. Already participated in this study once

• 10. Not considered suitable for the clinical trial by the investigators