Answers

1. Answer: ACDE

DISCUSSION: Many skulls from the Neolithic period have been found, some of which contain cranial defects with evidence of bone healing, indicating that these individuals underwent trepanation during life and survived the operation. The earliest known writing dealing with surgical topics is the Edwin Smith papyrus. In the works of Hippocrates is the first written account of trepanation. During the second half of the nineteenth century, general anesthesia was introduced and the principles of asepsis were developed. These steps were important for all areas of surgery, including neurosurgery. In addition, it became recognized that certain areas of the nervous system were especially important for certain neurologic functions and that intracranial and intraspinal abnormalities might be localized by the history and neurologic examination findings, thus providing a more specific target for neurosurgical exploration through the small bony openings to which surgeons were restricted at the time. Victor Horsley of London was the first surgeon to prepare himself specifically for surgery of the nervous system and to concentrate his efforts in that area.

2. Answer: C

DISCUSSION: Harvey Cushing (1869–1939) laid the groundwork for much of what is done in neurosurgery. For example, he standardized operative procedures and introduced many techniques and instruments that are still in use. He also made careful and detailed studies of intracranial tumors and established their classification. By his own multifaceted career and through his many students from around the world he influenced the development of neurosurgery to a degree not equaled before or since.


3. Answer: BDE

DISCUSSION: MRI has proved to be a better modality than CT for evaluation of disease of the central nervous system (CNS), such as diseases at the base of the skull (particularly the sellar and cerebellopontine angle cistern regions) and for most tumors, white matter disease (e.g., multiple sclerosis), early stroke, congenital abnormalities, vascular malformations, and spinal disease. New techniques of MRI such as fast spin echo (FSE) pulse sequence have been developed to detect mesial temporal sclerosis, which is the most common cause of intractable complex partial seizure. Differentiating pure compression fracture from metastatic disease of the vertebral bodies in a patient with known primary cancer is also possible by new MRI technique; however, for patients with certain types of metal (pacemaker, surgical clip, or foreign body, which may move in the magnetic field and cause injury to the patient or significant artifacts) within the bodies, MRI is contraindicated.

4. Answer: ACDE

DISCUSSION: Diffusion-weighted MR is a new development in MR applications and is sensitive to microscopic motion of water protons (Brownian motion). Initial applications have involved imaging of early stroke and neoplasia. Early evidence also suggests that diffusion-weighted imaging can differentiate tumoral edema from tumor and identify the nonenhancing part of the tumor. Doppler sonography, MRA, and CT angiography (CTA) are all useful for evaluating the stenotic condition of carotid bifurcation noninvasively. However, sonography is very operator dependent, and MRA commonly overestimates the degree of carotid stenosis resulting from the turbulence, dephasing at points of stenosis or irregularity. CTA obtained by spiral or helical CT has a good correlation rate with carotid angiography (92%). Conventional carotid angiography remains the most accurate imaging modality for evaluation of the stenosis of carotid bifurcation. Although CT and MRI have taken the place of myelography in evaluating neurologic diseases, it is still useful in detecting diffuse subarachnoid seeding, which may be difficult to identify on MRI. The bone detail and calcification are poorly identified on MR, so in a patient with facial trauma, CT is a better modality than MR. With MRS, metabolites within a selected region of interest (ROI) can be investigated, and spectral peaks that reflect the concentrations of the metabolite within the ROI can be obtained. The metabolites include lactate, neuronal marker (NAA), phosphorus metabolites, creatine, and choline. Reduction in the NAA level and elevation in lactate level could be noted in acute stroke.


5. Answer: ABCD



DISCUSSION: In children, brain tumors are more commonly situated below the tentorium than above it. In adults, the reverse is true. Cytologic examination of CSF may provide critical diagnostic information in a patient with meningeal carcinomatosis or subarachnoid spread of a primary brain tumor such as a medulloblastoma, but in most instances CSF examination is not of significant value. Furthermore, in a patient with a brain tumor lumbar puncture may be dangerous; it may promote brain herniation. If there has not been a surgical breach of the dura mater, primary brain tumors seldom spread to areas outside the intracranial and intraspinal compartments. Most gliomas, including astrocytomas, cannot be cured by surgical resection. The pilocytic astrocytoma of the cerebellum and the optic nerve glioma are exceptions to that rule. Neoplasms of astrocytic, oligodendroglial, or ependymal origin vary histologically along a spectrum from benign to malignant, with no sharp dividing line. Furthermore, even the most benign-looking ones tend to recur after surgical resection.