Effect of Dezocine Versus Nalbuphine Combined With Sufentanil on Postoperative Analgesia, Complications, and Free Flap Survival in Patients Undergoing Oral Cancer Radical Surgery: A Randomized Controlled Clinical Trial.

Pain intensity assessed at rest using the Visual Analogue Scale (VAS). The VAS is a 100-mm horizontal line where 0 mm represents "no pain" and 100 mm represents "the worst pain imaginable." Patients mark their current pain level on the line.

The occurrence of complications in the transferred free flap, assessed daily by clinical examination. Complications include hematoma, wound dehiscence, skin necrosis, and infection.

Sensory function recovery of the flap assessed using a Disk-Criminator to measure static and dynamic two-point discrimination (2PD). Lower values indicate better sensory discrimination.

Sensory function recovery of the flap assessed using Semmes-Weinstein monofilaments. The test determines the minimal force (g/mm²) required for the patient to perceive light touch, with lower values indicating better sensitivity.

The frequency of common postoperative adverse effects, including nausea, vomiting, pruritus (itching), dizziness, and somnolence (drowsiness), as recorded in patient charts and through direct questioning.

Level of sedation assessed using the Ramsay Sedation Scale (scores 1-6, where 1=anxious/agitated, 2=cooperative/oriented/tranquil, 3=responsive to commands only, 4-6=asleep with varying responses to stimulus).

The total length of hospitalization (in days) from the day of surgery until the day of discharge, meeting standard discharge criteria.

Measurement of intraoperative stability, including heart rate (beats per minute), blood pressure (mmHg), and peripheral oxygen saturation (SpO2, %). Data points are recorded every 5 minutes.

Sensory function recovery of the flap assessed specifically for pain perception threshold. This is measured using an algesimeter, a device that applies a standardized, gradually increasing mechanical stimulus (e.g., pressure in grams or Newtons) to the flap surface until the patient first reports a sensation of pain. The threshold value (e.g., in grams) is recorded.

The viability of the free flap assessed clinically. Flap survival is defined as a viable, perfused flap without the need for emergency reoperation due to total necrosis. The outcome is reported as the percentage of patients with a fully surviving flap at each follow-up time point.

The proportion of patients alive without evidence of cancer recurrence (local, regional, or distant) at 1 year after surgery.

Sensory function recovery of the flap assessed specifically for temperature discrimination. This is measured using the Thissen temperature sensitivity test or similar calibrated thermodes. The test evaluates the ability to distinguish between warm and cold stimuli applied to the flap surface, typically reported as correct identification rates or threshold temperature differences

The aesthetic and contour outcome of the reconstructed site is assessed by a surgeon using a standardized visual analog scale (VAS). The assessor rates overall appearance, symmetry, and contour integration with surrounding tissues on a scale from 0 (very poor) to 10 (excellent). The mean VAS score at each time point will be reported.

Functional recovery related to the flap reconstruction is assessed using a patient-reported outcome measure (PROM) focusing on speech and swallowing.