The goal of this pragmatic pilot clinical trial is to test the feasibility of the trial in terms of the number of patients recruited in a given period.

The main question it aims to answer is to assess the number of eligible patients and number of patients willing to participate per month.

Participants will be followed either by the team of "transitional pain service" (intervention group) or by a surgeon or the general practitioner (standard care). Depending on individual risk factors, patients in the intervention group will be offered some targeted measures, for example:

• hypnosis,
• patient education,
• evaluation by psychiatrist,
• psychotherapy,
• locoregional anesthesia,
• anti-depressant treatment Participants (in both intervention and standard care groups) will be asked to answer some questions before surgery, during the first week following the surgery and six months after the surgery.

Moderate to severe persistent post-surgery pain occurs in up to 12% of patients at 6 months post-surgery according to the large European study cohort. Our own data from a previous study at the University Hospitals of Geneva (HUG) (unpublished, alerte douleur-ALDO study) showed a prevalence of chronic post-surgical pain (CPSP) 6 months after selected types of surgery of 30.9%. Strategies to detect and prevent CPSP have not been applied systematically in clinical practice until now, despite routine surgical follow-up visits after surgery.

There are only few hospitals who have implemented a "transitional pain service (TPS)" to diminish the risk of the transition of acute to chronic pain after surgery, and the Anesthesia Department of the University Hospitals of Geneva is currently experimenting with such a team. A future study needs to validate the effectiveness of this approach.

The present study is planned as a pilot trial to test the feasibility, usability, acceptance, and to provide the parameters necessary to design this future study validating or refuting the utility of individually targeted combinations of preventive measures implemented by a "transitional pain service" in reducing the incidence of chronic pain 6 months after surgery.

The primary objective is to evaluate the feasibility of the trial in terms of the number of patients recruited in a given period.

Secondary objectives are:

• To determine patient acceptance of the proposed interventions and thus the percentage of patients receiving the planned interventions in reality in the treatment group
• To determine the percentage of patients in the control group receiving the treatments proposed in the intervention group by other caregivers outside of the study (patients in the control group may even receive such treatment by the investigators if requested by the patients or another physician)
• To evaluate the usefulness of a transitional pain service (TPS) from a patient perspective
• To determine the optimal primary outcome measure of the definitive trial

The study is a single-center, randomized controlled clinical pilot trial, designed to estimate the parameters necessary for planning a definitive, potentially multicentric study.

The randomization will follow 1: 1 allocation, with 2 parallel groups of patients with increased risk for CPSP (intervention group vs. a group with a routine follow up). A total of 60 patients will be included.

Patients undergoing spinal surgery, total knee replacement surgery or thoracic surgery will be screened for inclusion in the study.

Patients will be contacted for an informed consent, either by telephone and email, or by a personal visit before the surgery.

Following informed consent, all patients included will receive a set of questionnaires (by email or in paper form) concerning psychological risk factors and details about preexisting chronic pain.

Consenting patients will be randomized using a computer-generated list to either the treatment or the control group.

In neither group, surgical management of included patients will be influenced by the study.

In the intervention group, patients will be followed by the team of the "transitional pain service" of the University Hospitals of Geneva, and depending on individual risk factors, contraindications and following discussion with the patient (shared decision-making) the bundle of individually targeted measures.

In the control group, no specific measures will be applied, and patients are followed by their surgeon and general practitioner. In addition, during the hospitalization the Acute Pain Team may be requested. In case of persistent pain, it may happen that the surgeon or the general practitioner refers a patient to a chronic pain specialist. This will not lead to the exclusion of the patient.

Patients of both groups will receive identical follow-up questionnaires after surgery and outcome questionnaires by electronic or written form at 6 months after surgery.

Inclusion Criteria:

• patients scheduled for spine surgery or total knee replacement surgery or thoracic surgery
• patients of 18 years or more
• ability to speak and read French

Exclusion Criteria:

• inability to consent and to follow the procedures of the study
• emergency surgery