A Validation Study of Kwon's Prognostic Scoring System for Chronic Subdural Hematoma

Surgery for chronic subdural hematoma is one of the most frequent operations in neurosurgical practice. Chronic subdural hematoma mostly afflicts the elderly population. In 2018, Kwon and co-workers, published the Kwon scoring system (KSS), whereby 6 clinical and radiological factors are used to facilitate, and promote quality in, surgical decision-making and counseling of relatives. The aim of this study is to validate the KSS.

Patients operated on for unilateral chronic subdural hematoma at Örebro University Hospital, Sweden, between 2013 and 2019 constituted the study population. General data and the 6 outcome predictors according to the KSS were extracted from the electronic patient records. The preoperative modified Rankin Scale score and the postoperative 6-month modified Rankin Scale score were assessed.

We identified 133 patients (69.2% male) with a median age of 80.2 years (interquartile range 72.6-85.9). The median Glasgow Coma Scale score at admission was 15; 57.1% had motor deficits and 36.81% were disoriented. For 39.1% of the patients, the prognosis was a favorable outcome (modified Rankin Scale 0-1) at 6 months. The median KSS score was 9; 63.9% of the patients scored ≥9, and 36 (42.4%) of these patients actually achieved a favorable outcome. This corresponds to a prediction model sensitivity of 0.667 and specificity of 0.424. A receiver operator characteristic curve analysis of the model yielded an area under the receiver operator characteristic curve of 0.62441.

In our material, the KSS did not predict outcome precisely enough to base treatment decisions or counseling of relatives on the scores obtained.