How to compare clinical results of different neurosurgical centers? Is a classification of complications in neurosurgery necessary for this purpose?

A classification of complications in neurosurgery, to be approved and validated by the scientific community, has been advocated as the main vehicle for comparing different series of patients having undergone surgery in different centers and/or at different times. [12] The ultimate goal of such a classification would be-in the long period and from the point of view of healthcare policy-the quality improvement of health services to be offered to patients. Such improvement (which would also be relevant with regard to saving economic resources) could be achieved through an analysis-with quantitative (or at least objective) data-to establish which medical center guarantees the best clinical results in a specific surgical procedure. If a simple, practical-and therefore applicable in any medical center-classification of complications could achieve this purpose, it would be logical that all efforts should be made toward developing it. Should this aim not be pursued, or should it be achieved through different tools, the effort of defining a complications’ classification would be a mere intellectual exercise lacking any practical usefulness. Historical overview: The refinement of the definition of surgical complications and of classification of complications in general surgery The question of how to define negative results following invasive therapeutic procedures has been a matter for discussion for many years now in the field of general surgery. A classification of complications to be accepted by the entire scientific community has not been developed yet, even starting from the definition itself of complication; any proposed definition of complication,[4,5,6,16,17] as a matter of fact, has not been approved by those authors who later dealt with this subject. Sokol and Wilson,[17] for example, define as a complication “any undesirable, unintended, and direct result of an operation affecting the patient, which would not have occurred had the operation gone as well as could reasonably be hoped;” the authors themselves admit, however, that establishing in each case if a negative event could or could not be considered as a complication entails wide margins of subjectivity. The attempt to precise a classification of complications faces even harder obstacles, in as much the clarification of categories within which to classify the innumerable unexpected events that might occur in the surgical field will necessarily be either too generic or too specific. In the former case, such classification will include many different negative events not strictly homogeneous with regard to the cause of the complication; in the latter one, such classification will appear fastidious and not handy because of the excessive number of categories to be detailed. The most thorough paper in this field-dealing with cholecystectomies-was published by Clavien in 1992. [4] In this paper, a fundamental concept is introduced, that is, the grading of complications based on patients’ morbidity on the basis of the severity of any residual or lasting disability. Other authors also[8,9] stated that life quality measures should be used to evaluate surgery outcomes. Clavien,[4] moreover, recommended considering as “complications” only unexpected negative events; any predictable unfavorable outcome caused by a specific surgical risk inherent to the procedure being on the contrary a “sequela. ” This idea, also approved by other authors,[2,16,10] logically introduces the concept of a definition of surgical risk (i.e., the likelihood that a patient might develop a disability following a technically irreproachable surgical procedure). In the field of general surgery, Dindo et al., in 2004,[5] specified the complexity of surgery in three main categories as follows. Type A: surgical procedures without opening of the abdominal cavity; type B: abdominal procedures except liver surgery, representing instead type C procedures. Complications have been classified in five grades according to the importance of the therapy necessary to treat them. Grade I complications, requiring only routine drugs, include transient atrial fibrillation, atelectasis, transient elevation of serum creatinine; grade II complications, requiring specific drug treatment, include tachyarrhythmia, pneumonia, urinary tract infection; grade III complications, treated with invasive procedures, include bradyarrhythmia requiring pacemaker implantation, bronchopleural fistula, and stenosis of the ureter treated surgically. Grade IV includes single or multiorgan dysfunction and life threatening complications requiring intensive care unit management. Grade V represents the death of the patient. For each of the three classes of risk in which complications have been grouped, every type of negative event occurred much more frequently in group C patients (P < 0.0001).