This study aims to find how hypnosis performed just before a painful surgery can change anxiety level, in children aged 10 to 18 years.

Undergoing surgery can cause anxiety among children. Thus, peri operative anxiety can increase levels of pain, need for painkillers, and even length of stay in hospital.

Caring for children must take in account their anxiety. This anxiety can be treated through drugs or others means such as hypnosis. Thus, the use hypnosis in surgery has been very poorly assessed.

Parents will be given a consent form as well as an information note. This study aims to compare the level of post operative anxiety (D1)of children having hypnosis before receiving anaesthetics to the level of anxiety of children getting the usual care.

All the children included in this study will have a pre operative consultation with the Pain Management Nurse.

The study applies to inpatients, aged 10 to 18 years, who must go through orthopaedics surgery such as osteotomy (bone section) and spinal column surgery. 120 patients will be included in this study (60 in each arm) The primary outcome measure is the level of anxiety at day 1 (24 hours after surgery) Other outcome measure are

• the difference in anxiety level between D-1 (the day before surgery) and D1 (24 hours after surgery)
• the use of morphine during the first 24 hours This study is a prospective randomized trial, comparing a usual analgesics procedure to an experimental analgesics procedure including hypnosis before anaesthesia.

Expected impact of this study :change in procedures, decrease of anxiety levels in patients by the use of hypnosis before anaesthesia.

Inclusion Criteria:

• age 10-18 years
• Orthopaedics surgery (spinal column, osteotomy)
• ASA 1 & 2

Exclusion Criteria:

• casualty surgery
• patient or family unable to understand the study (language, disability ...)
• patient or family refusing the study