IMAGE-GUIDED CRYOABLATION

RENAL TUMOR — Cryosurgery Procedures

Image-Guided Cryoablation of Kidney Cancer:
Possible Side Effects
As technology and procedures for tumor ablation continue to evolve, experts must also evaluate new techniques for protecting organs, reducing pain, and avoiding complications.

Location of a lesion may be the greatest factor in predicting major complications. The closer the area to be treated is to a vulnerable structure, the more likely it is for a complication to occur. Uretal stricture, for example, is one of the most common complications that can occur when treating lesions of the kidney. Much of this risk can be avoided by the choice of ablation method. Damage to adjacent structures is more common with heat-based ablation techniques than with cryoablation, said Dr. Damian Dupuy, a professor of diagnostic imaging at Brown Medical School. One benefit of cryoablation is that it is very easy to see the exact ablation zone. This allows physicians to monitor how close they may be getting to a vulnerable structure and guard against stricture.

In The Journal of Urology, September 2004, DB Johnson, et al undertook a multi-institutional review to identify complications that are associated with percutaneous and laparoscopic ablative treatment for renal tumors. In this retrospective study, 139 of 271 cases utilized cryoablation as the ablative technique to treat kidney cancer. In the cryoablation group of 139 cases, there were a total of 19 complications (13.7%). Of these, 2 met the criteria for major complication (0.1%), while 17 were considered minor (12.2%). Of the 17 minor complications, 10 involved pain or paresthesia at the site of the probe insertion. The major complications included 1 significant hemorrhage that resolved with transfusion, and 1 case that converted to an open procedure because of the inability to access the tumor percutaneously.

It should also be noted that in the above study, it was found that the complication rate declined as the experience level of the physicians increased. Both major complications occurred in the first third of patients treated. Published data show that the location and size of the lesion can affect the risk for certain complications, as can the approach and technique employed to access the kidney. Overall, minimally invasive procedures have a lower complication rate than open surgeries.

Clearly, any time the kidney undergoes surgery, there is a chance of excessive bleeding. Patients who undergo cryoablation have less risk of bleeding because the surgeon is not actually cutting into the kidney. Similarly, not incising the kidney minimizes the risk of a complication known as “urine leak.” As used here, the term “urine leak” refers to urine leaking from the kidney’s internal collection system (see the section entitled The Kidneys). This happens when the collection system is disrupted by the incision made into the kidney. Sometimes this leakage can cause a cyst in or on the kidney that contains urine. This cyst is called a urinoma, and is a relatively rare complication that may require additional treatment.

During the double freeze-thaw process, injury to nearby structures such as the blood vessels, spleen, liver, pancreas, or bowel can occur. Great care is taken during every cryosurgical procedure to avoid these injuries, and pre-procedure imaging studies aid the surgeon in planning the best approach, technique, and placement of the cryoablation needles to minimize trauma to healthy kidney tissue and adjacent structures.

Since patients undergoing cryosurgery to remove a kidney tumor report minimal pain, complications arising from the administration of pain killers are also kept to a minimum. Physicians can control the amount of pain their patients may experience by carefully evaluating the site of the tumor within the organ being ablated, and the method used for ablation. The easiest way to avoid pain is to remove the greatest risk factor: heat. Cryoablation may be the best method to use when pain is a significant factor. The inherent anesthetizing properties of freezing have been shown to lead to reduced pain during the procedure.

Before leaving the hospital, patients are instructed to be vigilant for various signs of wound infection and hernia through one of the wounds, which are possible post-procedure complications.