Tracking Complications in Research


To measure and standardize 30-day complication rates across study sites, a two-stage process can be utilized. First, coordinators may gather adverse events from chart reviews and patient interviews in the following categories:

  • Death
  • Neurological complications
    • Motor deficit
    • Postoperative delirium
    • Sensory deficit
    • Cerebrovascular accident
    • Neuritis/neuralgia
    • Cardiac complications
      • Myocardial infarction
      • Cardiac arrest
      • Congestive heart failure
      • Arrhythmia
      • Persistent chest pain (Angina)
      • Pulmonary complications
        • Respiratory failure
        • Pulmonary edema
        • Intubation
        • Pneumonia
        • Pneumothorax
        • Gastrointestinal (GI) complications
          • GI bleeding
          • Persistent ileus
          • Bowel obstruction
          • Liver and/or biliary tract dysfunction
          • Renal complications
            • Acute renal failure
            • Thromboembolic complications
              • Deep venous thrombosis (DVT)
              • Pulmonary emboli
              • Symptomatic dural tears causing cerebrospinal fluid leak
              • Postoperative epidural hematoma
              • Urinary tract complications
                • Urinary tract infection
                • Incontinence
                • Retention
                • Device or instrumentation complications
                  • Device dislodgement or displacement
                  • Vertebral lesion or fracture
                  • Device or tine deployment malfunction related injury
                  • Other Infection complications
                    • Sepsis or bacteremia
                    • Lesion site infection
                    • Deep wound infection
                    • Superficial wound infection


In the second stage each identified complication can be graded accorded to the Clavien-Dindo classification of surgical complications. [1, 2] The Clavien-Dindo classification is a validated scale that grades severity of surgical complications according to the type of therapy provided to address the complication and is increasingly used and recommended for clinical trials whose outcomes include medical and surgical complications. The use of the Dindo-Clavien scale standardizes complication definition and grading across the sites of a study. According to this classification, grades I-II will be considered minor complications and grades III-V will be considered major complications. Clinical scenarios describing the surgical complications and grades are available on a website for training coordinators (  The data used to assign Clavien-Dindo grades are usually well documented and easily verifiable, and therefore, the Scale minimizes errors and bias, and improves consistency across sites.



1.            Clavien, P.A., et al., The Clavien-Dindo classification of surgical complications: five-year experience. Ann Surg, 2009. 250(2): p. 187-96.

2.            Dindo, D., N. Demartines, and P.A. Clavien, Classification of surgical complications: a new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg, 2004. 240(2): p. 205-13.