Postoperative pneumocephalus as a predictor of chronic subdural hematoma recurrence: a retrospective cohort analysis

Chronic subdural hematoma (CSDH) is a common neurosurgical condition, especially in the elderly, which is usually diagnosed by computed tomography (CT) scan and often treated surgically. After surgery patients shows favourable outcomes with improvement in symptomatology. Despite the availability of various surgical techniques, complications continue to occur frequently due to the advanced age of patients and underlying medical conditions. Burr-hole craniotomy followed by placement a closed-system drainage is widely considered the best treatment for CSDH, although technical challenges and a high recurrence rate remain. Postoperative pneumocephalus is a potential risk factor for recurrence. While the majority of patients recover well after surgery, recurrence or persistence of CSDH occurs in 0.35-33% of cases, sometimes necessitating additional surgeries.

This retrospective study comprehensively evaluates the clinical data of 229 patients diagnosed with chronic subdural hematoma (CSDH) who underwent surgical intervention, specifically burr-hole craniotomy with drainage between 2016 and 2021. The primary objective is to measure the prognostic significance of postoperative pneumocephalus as a predictor of recurrence of CSDH. Furthermore, the obtained univariate and multivariate regression analyses examines various patient-specific factors, including age, gender, location of CSDH (unilateral or bilateral), anticoagulation therapy status, neurosurgical follow-up outcomes, hospital readmission rates, and the incidence of repeat surgical procedures.

Among the analysed characteristics, postoperative pneumocephalus exceeding a specified volumetric threshold emerges as the only significant predictor of CSDH recurrence. This recurrence of CSDH is additionally associated with a substantial prolongation of the patient's hospitalization, highlighting its clinical and logistical significance.

A postoperative pneumocephalus is nearly unavoidable; however, optimizing surgical technique to minimize its volume below 5.2 cm³ reduces significantly the recurrence rate of CSDH.