Clinical adhesion score (CLAS): development of a novel clinical score for adhesion-related complications in abdominal and pelvic surgery

E.J. Lier*, B.A.W. van den Beukel, L. Gawria, P.J. van der Wees, L. van den Hil, N.D. Bouvy, Y. Cheong, R.L. de Wilde, H. van Goor, M.W.J. Stommel, R.P.G. ten Broek, CLAS Collaboration

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Background Adhesions are a major cause of long-term postsurgical complications in abdominal and pelvic surgery. Existing adhesion scores primarily measure morphological characteristics of adhesions that do not necessarily correlate with morbidity. The aim of this study was to develop a clinical adhesion score (CLAS) measuring overall clinical morbidity of adhesion-related complications in abdominal and pelvic surgery. Methods An international Delphi study was performed to identify relevant score items for adhesion-related complications, including small bowel obstruction, female infertility, chronic abdominal or pelvic pain, and difficulties at reoperation. The CLAS includes clinical outcomes, related to morbidity of adhesions, and weight factors, to correct the outcome scores for the likelihood that symptoms are truly caused by adhesions. In a pilot study, two independent researchers retrospectively scored the CLAS in 51 patients to evaluate inter-observer reliability, by calculating the Intraclass correlation coefficient. During a feasibility assessment, we evaluated whether the CLAS completely covered different clinical scenarios of adhesion-related morbidity. Results Three Delphi rounds were performed. 43 experts agreed to participate, 38(88%) completed the first round, and 32 (74%) the third round. Consensus was reached on 83.4% of items. Inter-observer reliability for the CLAS was 0.95 (95% CI 0.91-0.97). During feasibility assessment, six items were included. As a result, the CLAS includes 22 outcomes and 23 weight factors. Conclusion The CLAS represents a promising scoring system to measure and monitor the clinical morbidity of adhesion-related complications. Further studies are needed to confirm its utility in clinical practice.
Original languageEnglish
Pages (from-to)2159-2168
Number of pages10
JournalSurgical endoscopy and other interventional techniques
Issue number5
Early online date14 May 2020
Publication statusPublished - May 2021


  • adhesion-related complications
  • adhesions
  • clinical adhesion score
  • gynecological surgery
  • pain
  • quality-of-life
  • readmissions
  • small-bowel obstruction
  • Adhesions
  • Adhesion-related complications
  • PAIN
  • Clinical adhesion score


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