New diagnostic systems and innovative surgical and adjuvant treatments have contributed to improved diagnostic and surgical accuracy and provide more treatment options in patients with brain tumors. Despite these advances, craniotomy is still an important component in the therapy of brain tumors and is particularly important when the lesion is symptomatic due to its size causing compression of surrounding brain. Craniotomy allows for diagnosis of the lesion, but open surgery is not mandatory to obtain tissue for histology as it can also be obtained by stereotactic needle biopsy. The latter technique is particularly useful where there is no need for craniotomy for decompression or if the lesion is deep or in functionally important tissue. Additionally, the less invasive stereotactic biopsy is useful in individuals with compromised systemic health. It has been difficult to show that aggressive resection of a tumor by craniotomy significantly impacts survival in patients with malignant tumors of the brain.

In most cases, the radiographic features of a brain tumor are usually sufficiently specific to proceed with a craniotomy. Improved MRI sequences and MR spectroscopy have made considerable information available to the treating physician preoperatively. However, even with such improved information, it may still be impossible to exclude mass lesions that would not ordinarily be treated by a craniotomy, such as cerebral infarction, multiple sclerosis, and viral infections.