gms | German Medical Science

Objective: Chronic subdural hematoma (cSDH) constitutes one of the most prevalent intracranial disease entities requiring surgical treatment. A growing incidence is observed due to an aging population and increased use of prophylactic anticoagulant treatment. Although mostly taking a benign course after surgery, recurrence after cSDH treatment is common and associated with additional morbidity and costs. Routine post-operative imaging is brought into disfavor but still common in clinical practice. Aim of this study was to develop hematoma-specific parameters associated with increased risk of recurrence.

Methods: All consecutive cSDH admitted to a single university center between 2015 and 2019 were retrospectively considered for inclusion. Size, volume and midline shift of the initial hematoma was noted alongside relevant patient-specific risk factors. We applied a morphological classification system based on hematoma density, internal architecture and septation consisting of four grades, as a simplification of the Nakaguchi classification focusing on internal hematoma organization rather than stages within the natural healing process (0 = homogenous; 1 = mild compartimentalization, 2 = moderate compartimentalization , 3 = severe compartimentalization). Clinical outcome was assessed by means of the Glasgow outcome scale (GOS) up to 12 months after initial surgery. An odds ordinal logistic regression model was used to assess the score’s performance on predicting hematoma recurrence.

Results: We observed a recurrence rate of 31.6% (125 cases), in a series of 395 patients with a mean age of 75.2 ± 12.0 and a male to female ratio of 250 (63.3%) / 145 (36.7%). Apart from prior anticoagulant treatment (p = 0.012) neither demographic characteristics (age, gender) nor factors related to general patient comorbidity affected hematoma recurrence. Our classification based on internal organization outperformed existing classification systems in predicting hematoma recurrence. A decrease in grade was associated with an increase in the likelihood of developing recurrence, with an odds ratio of 1.944 (95% CI 1.101 to 3.431; p = 0.034) and the highest recurrence risk in the homogenous subtype of 45.7%.

Conclusion: We present a simplified easy to use morphological classification system for cSDH associated with a stepwise increased risk of hematoma recurrence. This provides a tool to identify patients who might still benefit from routine post-operative imaging in order to early identify hematoma recurrence.