CT Imaging features of Chronic subdural hematoma: Correlation with preoperative clinical findings and postoperative outcomes

Brief statement of the study hypothesis

Chronic subdural hematoma (SDH) is a blood collection in the subdural space that is more than 3 weeks old. Chronic subdural hematoma (CSDH) is a common neurosurgical condition, particularly affecting the elderly population. Despite being a well-recognized entity, CSDH presents several challenges in terms of management and outcome prediction.

The diagnosis is based on clinical symptoms and radiological investigation, mostly non-contrast CT scans. Computed Tomography (CT) imaging has become indispensable in diagnosing and managing CSDH. It provides critical information about the hematoma’s characteristics, including its size, density, and mass effect on surrounding brain structures. MRI brain scans have added advantages, providing information about the chronicity of the hematoma and the presence or absence of additional membranes.

TREATMENT

Conservative: Bed Rest, Osmotic Diuresis, Corticosteroids

Surgery: Craniotomy/burr hole (Single and double burr hole) drainage and Twist drill craniostomy

Endovascular intervention: Middle meningeal artery embolization

Worldwide double burr hole craniostomy is the most commonly performed surgical procedure for a chronic subdural hematoma. With the advantages of being the most straightforward neurosurgical procedure that can be performed even in the most resource-constrained settings, using the least instruments, the procedure is known for its inherent complications, the most notable among them being recurrence. The most common reason for these recurrences is the presence of additional membranes, resulting in a multicompartmental chronic subdural hematoma (SDH) in affected patients. Missing any of these membranes will increase the chances of recurrence. Identification and proper surgical management of these membranes are crucial to avoid recurrences.

Membrane identification

According to the prevailing literature, an MRI brain scan is more sensitive than a CT scan in delineating these membranes preoperatively, thereby helping to avoid recurrences. However, since CT scan heads are the investigation of choice in emergencies, surgery in most CSDH patients is performed solely based on the CT, further increasing the chances of recurrence. Hence, the author explores the preoperative CT and MRI brain findings in patients with CSDH, under the supervision of an experienced radiologist with more than five years of experience, to identify additional membranes and further correlate these findings during surgery to improve surgical outcomes.

Surgical aspects

Furthermore, in the surgical portfolio, the use of endoscopes in this surgery is again being touted as a means to avoid these recurrence risks. However, using a microscope as the sole surgical equipment in this surgery has never been considered to identify the membranes and fenestrate them, thereby increasing cure rates. Contrary to the fact that neurosurgeons remain more familiar with microscopes than endoscopes, it could probably be the only neurosurgical procedure where endoscope use is claimed to be superior, and the use of microscopes had never been considered. One reason could be a small burr hole is the only opening to enter inside the skull, and given apparent reason, entry and vision of a microscope may be considered less effective than endoscopic vision.

However, in the author’s view, as an experienced microscopic neurosurgeon, this can’t be a limitation, as he can easily see the surgical floor even with a 12mm burr hole and, if required, can perform his work efficiently of membrane fenestration through a seemingly small bur hole opening. Worldwide, especially in developing countries, the availability of CT scans is often better than that of MRIs in many places, and most neurosurgeons remain more comfortable with microscopes than endoscopes.

The primary purpose of the protocol

This study aimed to confirm the hypothesis that we can achieve a similar cure rate in terms of recurrence avoidance using our more universally available CT head and microscope modalities compared to an endoscope in CSDH patients. This will be a real help for our patients in middle and low-socioeconomic countries.