Experimental chronic subdural hematoma in mice. Gross morphology and light microscopic observations

History and current progress of chronic subdural hematoma

Chronic subdural hematoma (CSDH) is characterized by an encapsulated collection of old blood. Although CSDH has become the most frequent pathologic entity in daily neurosurgical practice, there are some unresolved research questions. In particular, the causes and recurrent risk factors of CSDH remain as an object of debate. The split of the dural border layer forms a few tiers of dural border cells over the arachnoid layer. Tissue plasminogen activator plays an important role as a key factor of defective coagulation. Historically, CSDH has often been treated via burr hole craniostomy using a closed drainage system. Several different operative strategies and peri-operative strategies such as the addition of burr holes, addition of cavity irrigation, position of drain, or postural position, have been described previously. Although the direction of the drainage tube, residual air, low intensity of T1-weighted images on MRI, and niveau formation have been reported as risk factors for recurrence, antiplatelet or anticoagulant drug use has not yet been verified as a risk factor. Recently, pharmaceutical strategies, including atorvastatin, significantly improved the neurological function in CSDH patients. Many case series, without randomization, have been reported; and given its promising result, several randomized clinical trials using pharmaceutical as well as operative and perioperative strategies were initiated to obtain sufficient data. In contrast, relatively fewer basic studies have achieved clinical applications in CSDH, although it is one of the most common clinical entities. Further scientific basic research may be essential for achieving a novel treatment strategy for CSDH.

A rat model of chronic subdural hematoma: Insight into mechanisms of revascularization and inflammation

Chronic subdural hematoma (CSDH) is a common neurological occurrence in the elderly population with significant impact on the quality of life and work. Studies have attempted to determine the risk factors and pathophysiological mechanisms of CSDH using models in numerous mammalian species. To date, these animal models have only been able to reproduce limited durations of hematoma which does not accurately reflect the chronic state of CSDH. To address some of these challenges we modified a rat model of CSDH using two consecutive injections of autologous blood resulting in a hematoma of more than three weeks. We observed inflammatory and angiogenic changes related to the development and recovery of CSDH. In this study the technique for producing a CSDH in a small animal model had a success rate of 78.13%. The hematoma was sustainable up to 24 days. Hematoma resolution was associated with a gradual decrease in local pro-inflammatory factors and gradual increase in anti-inflammatory factors as well as proliferation and subsequent maturation of newly formed vessels. These events were also associated with improved behavioral outcome. Expression of anti-inflammatory cytokines also paralleled reabsorption of the hematoma. Reduction in hematoma size was also associated with neurological recovery. These data suggest that vessel maturation and anti-inflammatory pathways may contribute to the resolution of CSDH and neurological recovery. The regulation of the two mechanisms is a potential target for the treatment of CSDH. The modified model of rat CSDH demonstrated a high level of reproducibility in our hands and may be useful in future CSDH studies.

Developing a model of chronic subdural hematoma

Chronic subdural hematoma (CSDH) is a common neurosurgical condition that has a high incidence in the increasing elderly population of many countries. Pathologically, it is defined as a persistent liquefied hematoma in the subdural space more than 3 weeks old that is generally encased by a membraneous capsule. CSDHs likely originate after minor head trauma, with a key factor in its development being the potential for a subdural cavity to permit its expansion within, which is usually due to craniocerebral disproportion. The pathogenesis of CSDH has been attributed to osmotic or oncotic pressure differences, although measurements of these factors in the CSDH fluid do not support this theory. Current belief is that CSDH arises from recurrent bleeding in the subdural space, caused by a cycle of local angiogenesis, inflammation, coagulation and ongoing fibrinolysis. However, because of a lack of detailed knowledge about the precise mechanisms, treatment is often limited to surgical interventions that are invasive and often prone to recurrence. Thus, it is possible that an easily reproducible and representative animal model of CSDH would facilitate research in the pathogenesis of CSDH and aid with development of treatment options.

Bilateral chronic subdural haematomas following traumatic cerebrospinal fluid leakage into the thoracic epidural space

This report describes a patient who developed bilateral chronic subdural haematomas after a stab injury to the thoracic meninges causing prolonged cerebrospinal fluid leakage into the epidural space. Diagnostic findings and therapeutic management are presented and possible pathogenic mechanisms are discussed. This case suggests that patients who have symptoms or signs of increased intracranial pressure after a penetrating spinal injury should be studied for subdural haematoma.