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Purpose To compare the convalescence and patient satisfaction between laparoscopic and percutaneous ablation for management of small renal masses.Methods We performed a telephone survey comparing convalescence and operative satisfaction of patients who underwent laparoscopic and percutaneous ablation between October 2000 and June 2006 at our institution. A retrospective chart review was performed to compare perioperative and postoperative convalescence parameters.Results A total of 93 patients underwent ablation of 103 small renal masses at our institution. Laparoscopic cryoablation was performed in 58 patients, percutaneous cryoablation in 20, and percutaneous radiofrequency ablation in 15 patients. Mean patient age was 66 years (range 24–86 years), median ASA (American society of Anesthesiologists) score was 3, and mean body mass index (BMI) was 30 kgmm2. There was no significant difference in the mean age, BMI, and median ASA scores between the groups. The mean diameter of the treated mass was slightly larger in the laparoscopic ablation group (2.6 cm) compared with masses in the percutaneous cryoablation (2.2 cm, P 0.027) and percutaneous radiofrequency ablation (2.2 cm, P 0.042) groups. All procedures were performed under general anesthesia. Compared with laparoscopic cryoablation, percutaneous cryoablation was associated with fewer probes used per lesion (P< 0.04), shorter mean anesthesia time (P 0.001), shorter mean hospital stay (P 0.007), early return to nonstrenuous activity (P 0.007), and shorter time to complete recovery (P 0.05). Similarly, compared with laparoscopic cryoablation, percutaneous radiofrequency ablation was associated shorter mean anesthesia time (P< 0.001), early return to nonstrenuous activity (P 0.009), early return to strenuous activity (P 0.007), early return to strenuous activity (P 0.04), and early return to work (P 0.05). There was no difference in the percent of patients who had a preablation biopsy, the median opioid analgesic requirement, and patient satisfaction measured on a 0 to 5 scale between various groups.Conclusion Our study suggests that percutaneous ablation in carefully selected patients is associated with early convalescence compared with laparoscopic ablation. [ABSTRACT FROM AUTHOR]

The destructive growth and collapse of cavitation bubbles are used for therapeutic purposes in focused ultrasound procedures and can contribute to tissue damage in traumatic injuries. Histotripsy is a focused ultrasound procedure that relies on controlled cavitation to homogenize soft tissue. Experimental studies of histotripsy cavitation have shown that the extent of ablation in different tissues depends on tissue mechanical properties and waveform parameters. Variable tissue susceptibility to the large stresses, strains, and strain rates developed by cavitation bubbles has been suggested as a basis for localized liver tumor treatments that spare large vessels and bile ducts. However, field quantities developed within microns of cavitation bubbles are too localized and transient to measure in experiments. Previous numerical studies have attempted to circumvent this challenge but made limited use of realistic tissue property data. In this study, numerical simulations are used to calculate stress, strain, and strain rate fields produced by bubble oscillation under histotripsy forcing in a variety of tissues with literature-sourced viscoelastic and acoustic properties. Strain field calculations are then used to predict a theoretical damage radius using tissue ultimate strain data. Simulation results support the hypothesis that differential tissue responses could be used to design tissue-selective treatments. Results agree with studies correlating tissue ultimate fractional strain with resistance to histotripsy ablation and are also consistent with experiments demonstrating smaller lesion size under exposure to higher frequency waveforms. Methods presented in this study provide an approach for modeling tissue-selective cavitation damage in general. [ABSTRACT FROM AUTHOR]