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

CLAS Collaboration

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


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 (US)
Pages (from-to)2159-2168
Number of pages10
JournalSurgical endoscopy
Issue number5
StatePublished - May 2021


  • Adhesion-related complications
  • Adhesions
  • Clinical adhesion score

ASJC Scopus subject areas

  • Surgery


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