Renal subcapular saline injection during percutanoues renal cryoablation to prevent bowel injury

To evaluate the feasibility of percutaneous injection of saline in the renal subcapsular space to prevent bowel injury and histopathologic effects of bowel cryolesion during renal cryoablation in a porcine model.

Six pigs underwent percutaneous renal cryoablation with two freeze cycles in the lower pole of both kidneys. Six kidneys were injected with 10 ml saline into the renal subcapular space before cryoablation. The bowel was brought into contact with the edge of the ice ball with laparoscopic assistance during renal cryoablation, on the side with saline injection as well as on the control side. One of these animals was kept for survival follow-up and laparotomy for 7 days post cryoablation. The bowel cryolesion sites were observed and compared based on the presence or absence of renal subcapsular saline injection.

The mean diameter of acute bowel injury with and without saline renal subcapsular injection was 7.25 +/- 1.26 and 14.5 +/- 0.58 mm, respectively. The influence of injecting a saline buffer was a significant decrease in the bowel cryolesion compared to controls (p = 0.0003). In addition, a pig kept for follow-up confirmed no bowel perforation after 7 days at a site that was cryolesioned on the side with renal subcapsular saline injection, but sustained bowel perforation in another segment lesioned by contact with a kidney without a saline injection. Gross and microscopic pathological examination was consistent with these interpretations.

Preliminary results in a porcine model show that percutaneous renal subcapsular saline injection is a feasible and promising technique for preventing bowel complications of percutaneous image-guided renal cryoablation.