Conditioned Open Label Placebo for Postoperative Pain Management

A Randomized Controlled Trial Evaluating the Efficacy of Conditioned Open Label Placebo (COLP) to Limit Opioid Reliance for Postoperative Pain Management

The primary objective is to evaluate the efficacy of two Conditioned Open Label Placebos (COLP): COLP pill and COLP odor to reduce opioid intake for postoperative (thoracic and spinal surgery) pain management compared to the opioid only usual treatment (TAU).

Patients, eligible for an elective thoracic or spinal surgery, will be randomized into either standard of care, COLP_pill or COLP_odor. Patients in COLP groups will be asked to pair each opioid intake with an open label placebo intake (either a pill or an inhalation) for postoperative (POD) day 0 to 17. From POD 2, patients in the intervention arms will be additionally asked to take OLP alone 3 times a day. Patients will have unrestricted access to pain killers. Patients will daily assess opioid intake, pain intensity, side effects, mobility and sense of agency using a e-dairy.

Inclusion Criteria:

• Spinal or thoracic elective surgery for the indications mentioned above
• Able to give informed consent
• Interested in trying COLP as complementary pain management therapy
• Able to fill a e-diary at home

Exclusion Criteria:

• Cognitive impairment (MOCA score <26)
• Inability to engage in the intervention of the study e.g. inability to communicate in French without a translator, severe hearing impairment without any hearing aid available at the time of intervention, anosmia or intolerance to eugenol.
• Acute psychiatric (e.g. psychotic or suicidal ideation) or somatic (e.g. unstable cardio-respiratory condition) co-morbidity preventing full engagement during intervention
• Opioid use disorder (toxicomania) or contraindication to pain management using opioids (allergy, refusal, ...)
• Intolerance to placebo ingredients