New Modality for Maximizing Cryosurgical Killing Scope While Minimizing Mechanical Incision Trauma Using Combined Freezing-Heating System

Abstract

Cryosurgery is a minimally invasive surgical technique using extremely low temperature to destroy undesired tissues. A surgical freezing margin of at least 1 cm is often recommended to avoid local tumor recurrence after surgery. For treating slender or elongated solid tumors in a conventional cryosurgery, simultaneous insertion of multiple cryoprobes is a necessity to guarantee an adequate killing scope. However, the risk of mechanical incision trauma may outweigh the benefits of such therapy. To resolve this difficulty, we proposed a new cryosurgical treatment modality, which can significantly maximize the killing scope while minimize the incision trauma, using the recently developed combined cryosurgical-hyperthermia treatment system (CCHTS). The method, named as one time’s percutaneous insertion while multiple times’ freezing∕heating ablation, is rather flexible in administrating a complex cryosurgical process and avoids certain shortcomings of conventional freezing strategies. Owing to the powerful heating function, the present probe can be easily moved back along its original incision tract to the desired positions immediately after initiating the heating. Then, a new iceball can be formed there while the iceballs generated before still remain unmelted in the following cycles. Consequently, a slender iceball could be generated to embrace the whole elongated tumor. This is, however, rather hard to achieve for a conventional cryosurgery with only one single freezing function or using only one probe. To visually demonstrate the feasibility and potential advantage of the present method, proof of concept in vitro gel experiments were performed. In addition, tests and corresponding theoretical simulations were performed on pork tissues. All the results indicate that the elongated iceball could be easily generated by using only one CCHTS probe owing to its strong freezing∕heating capability. In this way, a large number of incisions with multiple probes, commonly adopted in a conventional cryosurgery, can be avoided and the serious mechanical trauma including potential dangers can thus be significantly reduced. Meanwhile, the cost for the operation and postmedical care will be lowered. The present strategies are expected to be valuable in administrating a highly efficient and minimally invasive cryosurgery in the near future.