Background and aims
Chronic postsurgical pain with neuropathic characteristics (CPSNP) is often severe, having a negative impact on recovery from surgery. Early identification of patients at risk for CPSNP provides the opportunity to timely institute anti-neuropathic treatment. The aim of present study was to determine if the douleur neuropathique 2 (DN2) questionnaire identifies patients at risk for CPSNP. 
Methods
After ethical approval, patients after vascular, trauma, orthopedic and general surgery were interviewed on postoperative day 1  (day 1), day 14 and day 90 using the DN2 (first two items of the DN4 questionnaire) and the International Pain Outcomes Questionnaire. Pain was defined by a score of 4 or higher on a 11-point Numeric Rating Scale (NRS). CPSNP was defined as pain with a DN2 score of 3 or higher on day 90. Logistic regression analysis was performed using predictors a priori selected based on practical and pathophysiologic reasoning. 
Results
From January till August 2018, 368 postoperative patients were included of whom 63% responded on day 14 and 62% on day 90. At day 1, 14 and 90 respectively 78%, 40% and 31% of patients were in pain. Incidence of CPSNP was 16%.  Pain and a positive DN2 on day 1 could not predict CPSNP. However, pain and a positive DN2 on day 14 were both significant risk factors for CPSNP (resp. OR 1.25 (95% CI 1.02 to 1.54) and 1.65 (95% CI 1.09 to 2.48)). A positive DN2 on day 1 was significantly associated with pain at day 14 (OR 1.40, 95%CI 1.08 to 1.81). 
Conclusions: 
Pain and a positive DN2 on postoperative day 14 are significantly associated with CPSNP. Further research is needed whether initiation of anti-neuropathic treatment on day 14, can improve postsurgical recovery and prevent development of CPSNP.

04 - EARLY PREDICTION OF CHRONIC POSTSURGICAL NEUROPATHIC PAIN USING THE DOULEUR NEUROPATHIQUE 2 QUESTIONNAIRE