Subdural Levels of Interleukin 1-receptor Antagonist are Elevated in Patients with Recurrent Chronic Subdural Hematomas

Immunoprofile of Radiologic Chronic Subdural Hematoma Subtypes

OBJECTIVE

This study aimed to investigate the immunologic profile of chronic subdural hematoma (CSDH) subtypes based on their radiologic appearances, with a focus on comparing the membranous CSDH to other subtypes.

METHODS

We prospectively analyzed 170 CSDH cases from 138 patients, categorizing them into "Membranous" and 'Other' subtypes based on computed tomography scans. Samples were collected from the subdural fluid and systemic blood and analyzed for a panel of inflammatory markers. Demographic data, clinical characteristics, and time since trauma were also assessed.

RESULTS

Time since trauma to diagnostic computed tomography was significantly longer for the "membranous" subtype (P = 0.001). 'Membranous" CSDH exhibited a distinct immunoprofile, including lower hemoglobin levels (P = 0.0002) and higher concentrations of matrix metallopeptidase 9 (P = 0.005) and interleukin-8 (IL-8) (P < 0.0001). Additionally, "Membranous" CSDH showed elevated levels of interferon gamma-induced protein 10, monokine induced by gamma interferon, and uPAR compared to 'Other' subtypes, with significant correlations between interferon gamma-induced protein 10 and monocyte chemoattractant protein-1 (P = 0.013), monokine induced by gamma interferon (P = 0.002), and urokinase-type plasminogen activator receptor (P = 0.006). IL-8 levels also correlated significantly with monocyte chemoattractant protein-1 (P = 0.02), suggesting distinct inflammatory pathways in the "Membranous" subtype.

CONCLUSIONS

This study demonstrates that CSDH subtypes, particularly the "Membranous" subtype, possess a distinct immunologic profile. These findings provide novel insights into CSDH pathophysiology. The unique inflammatory landscape of "Membranous" CSDH, marked by elevated matrix metallopeptidase 9 and IL-8 levels, may contribute to its chronic nature.

Inflammatory Risk Factors for Chronic Subdural Hematoma in a Nationwide Cohort

Background

The discovery of biomarkers in chronic subdural haematomas (CSDH) suggests that inflammation is part of CSDH pathophysiology. It is unknown whether inflammation reflects an independent CSDH driver or haematoma degeneration. This knowledge holds a potential target for anti-inflammatory treatment in patients at risk of CSDH. This study investigated the association of pro- and anti-inflammatory factors with CSDH development.

Methods

This cohort study included all individuals in Denmark over 50 years between 2007-2018. The outcome was first-time CSDH surgery. Hazard ratios (HR) according to potential risk factors were estimated using Cox regression, with age as underlying time scale.

Results

Among the 2,391,853 individuals, head trauma was registered in 427,612 individuals (17%), and among these, only 812 were operated for CSDH (0.18%). Among individuals without registered head trauma, the pro-inflammatory conditions of alcohol addiction, diabetes, anti-hypertensive treatment, and chronic hepatic disease were significantly associated with CSDH among individuals (50-74 years). The use of glucocorticoids displayed a decreased risk in cohort members aged 75 and older. Non-steroid anti-inflammatory drugs and statins appeared to be risk factors for CSDH in individuals between the ages of 50-64 and 65-74.

Conclusion

Although head trauma was a risk factor for CSDH, the absolute risk was low (0.18%), which does not support preventive measures after emergency room contacts for head trauma. Interestingly, pro-and anti-inflammatory factors were significantly associated with CSDH in patients without registered head trauma, and the pronounced age-dependency of the associations suggests that the pathophysiological mechanisms vary with age.

Urokinase Plasminogen Activator Receptor: An Important Focal Player in Chronic Subdural Hematoma?

Chronic subdural hematoma (CSDH) development involves inflammatory, angiogenetic, and fibrinolytic mechanisms, several components of which are now unraveled through intensive research. The urokinase plasminogen activator receptor (uPAR) is part of the plasminogen activator system and possesses inflammatory, angiogenetic, and fibrinolytic capabilities. As a first, this study aims to identify uPAR in the hematoma fluid, hematoma membrane, dura mater, and systemic blood from patients with CSDH and, if present, to investigate if the uPAR level at the time of surgery may be a predictor for later developing recurrent CSDH. uPAR expression in the hematoma membrane and dura mater was analyzed using immunohistochemistry and presented as the H-score of the positive immunostaining. The uPAR levels in the hematoma fluid and systemic blood were determined using a multiplex antibody bead kit (Luminex). Samples were collected at the time of the first CSDH surgery, and in the case of recurrent CSDH within 90 days, the samples were again collected at reoperation. A comparison of uPAR expression between the hematoma membrane and dura mater, as well as uPAR levels in systemic blood and hematoma fluid, was performed using the Wilcoxon rank sum test. We included 112 patients, 26 of whom had recurrent CSDH. The median hematoma uPAR level was 22,125 (14,845-33,237) and significantly higher than the median systemic blood level of 789 pg/L (465-2,088) (p < 0.001). Similarly, the uPAR level of the hematoma membrane was 14.3 (7.54-44.8) and significantly higher than the dural uPAR level of 0.81 (0.3-1.98) (p < 0.001). For the first time, we identified uPAR in the subdural fluid, hematoma membrane, dura mater, and systemic blood from patients with CSDH. The high expression of uPAR in the subdural fluid and hematoma membrane indicates that the mechanisms of CSDH are predominantly in the subdural fluid collection and surrounding hematoma membrane.

The cellular composition of chronic subdural hematoma

INTRODUCTION

The pathophysiology of chronic subdural hematoma (CSDH) remains to be fully understood. Basic knowledge of the composition and features of cells in the CSDH fluid may contribute to the understanding of the seemingly complex processes involved in CSDH formation and recurrence. This study is the first to examine the composition of cells and of cellular features in both systemic blood and subdural fluid from CSDH patients. We hypothesized that the cellular composition and features in the hematoma fluid may be; 1) different from that in the systemic blood; 2) different between patients with and without recurrence; 3) and different between the first and second operation in patients with recurrent CSDH.

METHODS

Systemic blood and subdural hematoma fluid were collected from CSDH patients with and without recurrent CSDH at the time of primary and secondary surgery. Analyses of cells and cellular features included total number of white blood cells, erythroblasts, reticulocytes, platelets, neutrophilocytes, lymphocytes, monocytes, eosinophils, basophils, reticulocytes, immature granulocytes, mean corpuscular cell volume (MCV), mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, hemoglobin and hematocrit.

RESULTS

Of the 85 included patients, 20 patients were operated for a recurrent CSDH within 90 days follow-up. All cells found in the systemic blood were present in the CSDH fluid, but the composition was different (p < 0.0001). MCV was higher in the hematoma fluid from the primary operation of patients later developing a recurrent CSDH compared to patients not developing recurrence (p = 0.009). Also, the percentage distribution of inflammatory cells in hematoma fluid from patients with recurrent CSDH was different between the first and second operation (p = 0.0017).

CONCLUSION

This study is the first to investigate the cellular composition of CSDH fluid. Compared to systemic blood and to a reference distribution, an increased number of immune cells were present in the hematoma fluid, supporting an inflammatory component of the CSDH pathophysiology. MCV was higher in the subdural fluid at time of the first operation of CSDH patients later developing recurrence.

CLINICAL TRIAL REGISTRATION

The study was approved by the Scientific Ethical Committee of the Capital Region of Denmark (Journal no. H-20051073.

Intraoperative Irrigation and Risk of Chronic Subdural Hematoma Recurrence

BACKGROUND AND OBJECTIVES

In most neurosurgical centers, irrigation is an essential part of the surgical procedure for chronic subdural hematoma (CSDH). However, it is unknown whether the volume of irrigation fluid affects the risk of CSDH recurrence. This study aimed to investigate a potential association between the volume of irrigation fluid used during burr hole evacuation of CSDH and the risk of CSDH recurrence.

METHODS

This study is a subanalysis of 2 randomized trials (Drain Time & Drain Time 2) designed to investigate the effect of drainage duration on the recurrence of CSDH. Intraoperative irrigation volume was measured, and patients were followed for 90 days for recurrent CSDH.

RESULTS

A total of 525 patients with CSDH were included. There was no significant difference in the volume of irrigation fluid used between patients with recurrence (mean = 938 mL, SD = ±552) and without recurrence (mean = 852 mL, SD = ±454) ( P -value = .15). Patients with recurrent CSDH had larger primary CSDH volumes (mean = 134 cm 3 , SD = ±69) than patients without recurrence (mean = 119 cm 3 , SD = ±58) ( P = .04). Multiple logistic regression analysis revealed no association between irrigation volume and recurrence, also when stratified for hematoma size.

CONCLUSION

There was no significant association between irrigation volume and recurrent CSDH within 90 days in patients undergoing burr hole surgery for CSDH.