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reoperation, there is also a 20% increase in morbidity and mortality (2). Cryosurgery, on the other hand allows reoperation through a small incision and burr hole on both superficial and deep lesions, leaving the necrosed tumor tissue in place until absorbed by the body. This dramatically decreases the operative morbidity and mortality (18). While there has been no large double blind randomized study of the use of cryosurgery in human intracranial gliomas there have been trials with other sites of malignancy. Onik (21) reported very good results (27% disease free at 21 months) when treating otherwise unresectable liver metastasis that were adjacent to major vascular structures with cryosurgery. Prostate surgery can be treated with multiple cryogenic probes with ultrasound guidance, again with very good results, 92% disease free at 3 months (22). Since reoperation can provide the best chance of survival in patients with GBM, cryolesioning could extend the benefits by drastically reducing the morbidity and mortality associated with conventional surgery.
AVMs
Walder (30) believes that the most impressive application of cryosurgery is its use in freezing inoperable cerebrovascular abnormalities. Cryosurgery produces thrombolization in 50% of the cases and endothelial proliferation of an additional 50% of the lesions as demonstrated by angiography after 5 weeks. The endothelial proliferation is a prophylaxis against rebleeding. The procedure itself is equally as safe as thalamotomy in the treatment of movement disorders, no hemorrhages were observed during or after freezing. The size of the arteriovenous malformation (AVM) is not a contraindication to cryosurgery as may be the case with radiosurgery but instead determines the number of times that the cryoprobe needs to be utilized, 10 to 25 sets is not unusual. Walder recommends that in inoperable AVMs because of the location, cryosurgery could provide an alternative to no surgery at all.
OTHER USES
Cryosurgery has been used in circumstances when it is necessary to create a lesion or destroy tissue deep in the brain or as an alternative to radiofrequency. Cryosurgery has been utilized to control epilepsy (28), to assist in retraction of intracranial vascular tumors (11), as a cryoblockade of the bilateral amygdala to prevent ventricular fibrillation (3), in the treatment of pituitary tumors (6, 23), for the relief of intractable pain (15), for freezing tonsils, to facilitate removal of eye cataracts (10) and for the treatment of hemorrhoids (13). Furthermore, Rowbotham in 1959 (25) wondered if it was possible to determine the temperature that might kill malignant cells selectively. Although this is a different approach to cryosurgery the question has not been answered.
CASE REPORT
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