Preoperative neutrophil to Lymphocyte Ratio as a predictor of Chronic Subdural Hematoma recurrence

Introduction: Chronic subdural hematoma (CSDH) is a common pathology with a recurrence rate ranging from 2 to 37%. Recently, several studies have suggested the possible relationship between the increase in Neutrophil to Lymphocyte Ratio (NLR) and the poor outcome of different pathologies. The aim of this study is to investigate the potential correlation between the pre-operative NLR value and the risk of CSDH recurrence. Methods: From January 2015 to December 2019, 261 CSDH patients were surgically treated at our Department. Data regarding patients' baseline characteristics and their hematologic parameters were retrospectively collected from medical records, while the maximum thickness of the hematoma was measured on pre-operative CT scans. Patients with concomitant cerebrovascular, infective, inflammatory, haematological, or neoplastic diseases, INR > 1.5, previous craniotomy, ventriculoperitoneal or ventriculo-atrial shunt or missing data were excluded from the study. Minimum and maximum follow-up were 4 months and 3 years respectively. Results: A total of 104 patients were enrolled in this study. Mean age was 77.5 ± 14.1 and 77.2 ± 14.2 years respectively in the non-recurrence and recurrence groups (p value, 0.924). Preoperative maximum hematoma thickness resulted 2.2 ± 0.5 cm in patients without recurrence and 2.4 ± 0.6 cm in those with CSDH recurrence (p value, 0.113). Mean pre-operative NLR was higher (12.7 ± 10.4 vs 6.3 ± 4.8) in the recurrence group than in the non-recurrence one. This difference resulted significant (p value, 0.001) at statistical analysis. Conclusions: Pre-operative NLR is an easily obtainable marker, which may be helpful in clinical practice to stratify the risk of CSDH recurrence.