I Stereotactic surgery
Stereotactic surgery is a neurosurgical technique that makes detailed use of the relationship between the three-dimensional space occupied by intracranial structures or lesions and an extracranial reference system to guide instruments to such targets accurately and precisely. This type of technique is used when the lesion is small and located deep within brain tissue or as a means of obtaining a biopsy of a lesion for diagnosis.
Stereotactic procedures can be frame based or image guided (frameless). If the frame-based procedure is used, the frame is anchored to the skull with either four pins or four screws. Application typically takes place outside the operating room using a local anesthetic. In a cooperative adult, frame application takes only 5 to 10 minutes. For children, general anesthesia is used. If the image-guided procedure is used, small markers called fiducials are placed on the head with adhesive. An imaging study is then performed to provide a system of reference.
2. Preoperative assessment
a) History and physical examination: Neurologic symptoms vary, depending on the site and size of the lesion; they should be carefully documented. In addition to the routine test, CT is performed preoperatively with the frame in place to determine stereotactic coordinates. After the coordinates are established, airway access is restricted because the frame should not be moved on the head until the operation is complete unless an emergency occurs.
c) Diagnostic tests: CT of the head and other tests are as indicated by the history and physical examination.
