Including the bowel within the iceball during cryoablation: a retrospective single-center review of adverse events.

Purpose: To evaluate the safety of including bowel in the ice-ball during cryoablation.

Materials and methods: 43 patients who underwent 50 cryoablations between 1/1/2012 and 2/1/2023 were retrospectively reviewed and compared to a control cohort of those undergoing cryoablation without bowel involvement (n=86). Adverse events (AEs) were stratified by the Society of Interventional Radiology Adverse Events classification system, 2017 (1). Adverse events occurring within 12 months and factors that may affect the AE rate, such as degree of bowel involvement and portion of bowel involved, were reviewed.

Results: Fourteen AEs occurred in 13 patients (13/43, 30.2%). This included 7 grade 1 AEs (7/43,16.3%), 3 grade 2 (3/43,7.0%) and 4 grade 3 (4/43,9.3%). Of them 1 grade 3 AE was judged to be related to bowel involvement (1/43,2.3%). When comparing AEs by degree of bowel wall involvement, there were more injuries with the full thickness bowel wall cases (6/9,66.7%), compared with partial thickness, but the findings were not statistically significant (p=0.140). When looking at AEs by portion of the intestine involved, it was found that 7 (7/14,50%), 10 (10/17,58.8%), and 4 (4/19, 21.1%,p=0.055) were found when stomach, small bowel or large bowel was involved respectively. No significant difference in AEs (13/43,30.2% vs 31/86,36%,p=0.511) or severe AEs (4/43, 9.3% vs 9/86, 10.5%, p=0.836) was found between the study and control cohorts.

Conclusion: Findings from this single center retrospective experience suggest that bowel wall involvement by the ice ball during cryoablation resulted in a lower-than-expected rate of adverse events for bowel-related injuries.