Understanding of Disease
- First reported 1930: The first cases of ependymoma in children were reported in the 1930s.
- Natural history fatal: As more experience was gained, it became apparent that if this tumor was left untreated, its natural history proved fatal for the patient within 3 years (1).
- Subtotal surgery unsuccessful: Since supratentorial ependymomas often present when they are a large size, surgery is usually performed. In several series of patients from the 1970s in whom surgery alone was performed, only a small proportion of patients did not have a recurrence (2).
- Better outcome with radical surgery: In the 1980s and 1990s, better diagnostic imaging and improved surgical techniques showed that when complete tumor resection was achieved, 60–70% of patients had long disease-free periods of survival (remissions of 24–70 months) (3, 4). Recurrences sometimes occurred as late as 5 years or more after diagnosis, and these tumors were then treated with repeat surgery and radiation therapy.
- Currently radical surgery preferred: The present consensus of opinion is that a gross total resection correlates with the best outcome (5, 6). However, other risk factors have to be considered, including age, tumor location, risk of neurological damage precluding total resection, anaplastic histology, and withholding radiation therapy.
Technological advances that have enabled more extensive resections, with lower rates of morbidity and mortality, are as follows:
- Advanced instruments: Microsurgical instruments, non-stick bipolar diathermy forceps, ultrasonic aspirator (CUSA), and image-guidance/neuro-navigation equipment have diminished injury to adjacent normal tissues.
- Smaller, accurate craniotomies: Smaller, accurate craniotomies can be performed with more complete tumor resections using modern imaging and image guidance.
- Intraoperative imaging: Real-time imaging allows the surgeon to ensure completeness of tumor resection.
- Cortical mapping and nerve stimulation: In eloquent areas, such as motor cortex, the risk for neurological damage can be minimized using modern mapping and monitoring techniques.
- Microsurgical techniques: Their use results in less trauma to normal surrounding brain parenchyma.