Pilot Trial: Postoperative Opioid-free Analgesia

At least 70% of patients undergoing the outpatient general surgery procedures of interest (screened participants) are eligible to be randomized.

At least 90% of the surgeons who agreed to have their patients randomized comply with the agreement (i.e. not change their minds).

At least 50% of eligible patients agree to participate in the study and are randomized.

At least 80% of the randomized patients comply with their allocated treatment (i.e. will take their pain medications as prescribed).

At least 80% of the randomized patients complete outcome assessment at 30 days after surgery.

Among all questionnaires distributed to patients who complete outcome assessments, the proportion of missing data (i.e. non-response to questionnaires) is less than 10%.

Among patients who complete outcome assessments, the proportion of missing data is less than 10% (i.e. non-response to specific questionnaire items).

Measured using the Brief Pain Inventory Short-Form, which addresses pain severity and interference in the last 24 hours. Scores range from 0 to 10; higher scores represent worse pain outcomes.

The time to the first report of stopping the use of pain medication.

Measured using the PROMIS-29 questionnaire, which assesses 7 domains of health (physical function, anxiety, depression, fatigue, sleep disturbance, ability to participate in social roles and activities, and pain interference). Norm-based scores are calculated for each domain, such that a score of 50 represents the mean of the general population (standard deviation=10). Higher scores represent more of the domain being measured.

Measured using the Perioperative Opioid-Related Symptom Distress Scale, which records symptom distress due to common adverse effects experienced by patients who receive opioids to relieve postoperative pain.

The reported rates indicate the number of reported events per period of evaluation.

Measured using the Prescription Opioid Misuse Index, which includes questions regarding excessive dose, frequency of use, need for early refills, feeling high from the medication, taking the medication due to stress and obtaining prescriptions from multiple physicians. Scores range from 0 to 6; an affirmative answer to >1 question indicates the patient exhibits prescription opioid misuse.

Graded by severity using the Dindo-Clavien classification. This system grades complications according to the therapy needed for treatment (grades I to IV, best to worse).

Grade I: Any deviation from the normal postoperative course without the need for pharmacological treatment or surgical, endoscopic, and radiological interventions.

Grade II: Complications requiring drug treatments other than those allowed for Grade I complications; this includes blood transfusion and total parenteral nutrition (TPN) Grade III: Complications requiring surgical, endoscopic or radiological intervention Grade IIIa - intervention not under general anaesthetic Grade IIIb - intervention under general anaesthetic

Emergency department visits, hospital readmissions.

Obtained from spontaneous patient reporting (Trigger question "Did you have any significant medical problem related or unrelated to your surgery since the last study assessment?"). Events were coded using the MedDRA coding dictionary, graded by severity according to the Common Terminology Criteria for Adverse Events (CTCAE) and assessed for potential causality using the WHO/UMC system.

Filling of opioid prescriptions up to 3 months after surgery.

Measured using the Comprehensive Complication Index score at 30 after surgery. The score ranges from 0 to 100; higher scores indicate greater severity of complications.