Pain Evaluation Across Robotic and Laparoscopic Surgery for Colorectal Procedures

This is a prospective, single-center, observational study conducted at the Hospital General Universitario Gregorio Marañón in Madrid, Spain. The study compares postoperative pain outcomes in patients undergoing elective colorectal surgery via two different minimally invasive surgical approaches: laparoscopic and robotic-assisted surgery.

Eligible participants will be adults (≥18 years) undergoing elective colon or rectal surgery for benign or malignant disease, provided they meet the criteria of the hospital's Enhanced Recovery After Surgery (ERAS) program, known locally as the RICA protocol. Patients with open surgery indications, chronic analgesic use, or other exclusion criteria (e.g., inflammatory bowel disease, multivisceral resections, chronic opioid use, or inability to follow the RICA protocol) will not be included.

Pain will be assessed using the Visual Analog Scale (VAS) at standardized time points: on arrival at the post-anesthesia care unit, upon admission to the surgical ward, and at 24, 48, and 72 hours postoperatively, as well as at discharge. Intraoperative nociception will also be evaluated using the Nociception Level Index (NOL), an objective measure that reflects the patient's pain response during surgery.

Additional outcomes include postoperative opioid consumption, length of hospital stay, complication rates (using the Clavien-Dindo classification), hospital readmissions, reintervention rates, and patient-reported quality of life measures at 1, 3, 6, and 12 months after surgery, using validated questionnaires (QLQ-C30, QLQ-CR29, and EQ-5D).

Data will be collected and stored securely using the REDCap electronic data capture system, ensuring patient confidentiality. The estimated sample size is 80 patients (approximately 40 in each group), and the total study duration is expected to be 2 years for recruitment and follow-up, with an additional period for data analysis and publication.

The goal is to generate high-quality evidence to help guide clinical decision-making in the selection of surgical approaches for colorectal surgery, focusing on reducing postoperative pain and enhancing recovery.

Inclusion criteria

• Adults aged 18 years or older
• Signed informed consent
• Meeting inclusion requirements of the hospital's Enhanced Recovery Protocol (RICA program), including:
• Adequate cognitive status
• ASA (American Society of Anesthesiologists) classification I, II, or III
• Elective colon surgery (right or left hemicolectomy) for malignant disease
• Planned laparoscopic or robotic surgical approach
• Preoperative evaluation completed as per RICA protocol (nutritional, nursing, anesthetic, and pharmacy assessments)

Exclusion criteria

• Patients with a preoperative decision for open surgery
• Patients undergoing rectal surgery (partial or total mesorectal excision without protective stoma)
• Patients with inflammatory bowel disease requiring colorectal resection
• Patients requiring multivisceral resection due to oncologic indications identified intraoperatively
• Extraction incision different from Pfannenstiel approach
• Current or past history of chronic opioid use or opioid abuse
• Current or past history of benzodiazepine use or abuse
• Chronic use of analgesics for other comorbid medical conditions
• Current or past history of recreational drug use or abuse
• Non-compliance with the RICA protocol, including:
• Lack of preoperative nutritional, nursing, anesthetic, or pharmacy evaluation
• Non-adherence to preoperative care protocols (e.g., premedication, fasting, carbohydrate loading, thromboembolism prophylaxis, antibiotic prophylaxis, anesthetic care guidelines)