This study aims to evaluate the incidence of longterm pain after spinal fusion surgery in children and adolescents. In the second part of the study a randomized double-blind clinical trial will be conducted. We compare the effect of pregabalin versus placebo on postoperative pain and oxycodone consumption. We will also be able to evaluate the effect of pregabalin on neurophysiological monitoring during surgery.

Adolescent idiopathic scoliosis is the most common indication for major surgery during adolescence. Postoperative pain is a major concern in these adolescents with major surgical trauma. Spinal cord monitoring is an essential part of spinal deformity correction, but the effects of pregabalin on these measurements are not known.

In order to evaluate the incidence of longterm postoperative pain in children after spinal surgery the first part of our study will be retrospective. We will send a symptom and pain questionnaire to all children, who have been in spinal fusion surgery at our university hospital between the years 2009-2015. The questionnaire will include Oswestry Low Back Pain Questionnaire, pain drawing and SRS-24. The Oswestry Disability Index is currently considered by many as the gold standard for measuring degree of disability and estimating quality of life in a person with low back pain.

In the second part of our study a randomized double-blind clinical trial will be conducted comparing the effect of pregabalin and placebo on postoperative pain and oxycodone consumption. In addition the effect of pregabalin on neurophysiological monitoring in adolescents undergoing surgery for spinal deformities will be assessed. Finally, the prevalence of persistent postsurgical pain will be evaluated at 6, 12 and 24 months after surgery.

To obtain statistical power of 80% and a type I-error level of 0.05, 60 adolescents (30 in control and 30 in active treatment group) will be recruited according to CONSORT guidelines.

The aim of the study is to evaluate the effect of pregabalin given twice preoperatively and for five days postoperatively on postoperative pain. Pain will be measured using visual analogue scale (VAS). Oxycodone administered using patient controlled anesthesia (PCA) will be used for analgesia. Persistent pain at 6, 12 and 24 months will also be evaluated. In addition, the effect of preoperative pregabalin on motor evoked potentials (latency, amplitude, currency needed to evoke potentials) during spinal cord monitoring as well as perioperative EEG findings and on the consumption of anesthetics.

Inclusion Criteria:

1. Adolescent (10-21 years) undergoing spinal fusion for idiopathic scoliosis, spondylolisthesis or Scheuermann kyphosis.
2. Posterior spinal fusion
3. No contraindication for Pregabalin use
4. ASA I-III
5. Written informed consent

Exclusion Criteria:

1. Other spinal pathology or other associated medical condition
2. Major neurologic developmental delay
3. Need for anterior surgery or for vertebral column resection.
4. Preoperative opioid use
5. Inability to use PCA