Drain versus no drain in elective open incisional hernia operations: a registry-based analysis with 39,523 patients.

With 71.3%, the use of surgical drainages has a high level of acceptance in elective open incisional hernia operations. The worse outcome of patients is associated with the use of drains, independent of other influencing factors in the model such as patient or surgical characteristics. The use of drains may be a surrogate parameter for other unobserved confounders.