Predictors of re-operation in the setting of non-acute subdural hematomas: A 12-year single center retrospective study.

Non-acute subdural hematomas (naSDH) may recur after surgical treatment. A second operation affects the quality of life and functional outcome of the patients, and lengthens hospital stay. We aim to identify the predictors of reoperation as the healthcare system in the US is moving towards patient-centered care. This retrospective study included patients treated surgically with burr-holes or mini-craniotomy for non-acute subdural hematoma between February 2006-June 2018. Univariate and multiple logistic regression models were performed. 23 (12.0%) patients had reoperation. Controlling for all the factors, postoperative acute blood in the operative bed was the strongest predictor of recurrence of naSDH (OR = 37.93, 95% CI: 5.35-268.87, p < 0.001). Those undergoing a mini-craniotomy were over six times as likely to experience a recurrent SDH compared to those operated on via burr holes (OR = 6.34, 95% CI: 1.21-33.08, p = 0.029). Finally, patients with a past medical history of thrombocytopenia were nearly six times as likely to experience a recurrence of SDH (OR = 5.80, 95% CI: 1.20-28.10, p = 0.029). Postoperative hematoma thickness showed a trend toward significance such that thicker hematomas were associated with an increased likelihood of experiencing a recurrent SDH. In conclusion, we found that operative technique, thrombocytopenia and the presence of postoperative hemorrhage are significant predictors for reoperation. Given the current interest in endovascular embolization for SDH, understanding these risk factors may aid in determining indications for such adjunctive treatment.