CT-guided instillation of 5% dextrose in water into the anterior pararenal space before renal radiofrequency ablation in a porcine model: positive and negative effects

Asian Conference on Tumor Ablation guidelines for renal cell carcinoma

Thermal ablation has been established as an alternative treatment for renal cell carcinoma (RCC) in patients who are poor candidates for surgery. However, while American and European guidelines have been established for American and European patients, respectively, no ablation guidelines for Asian patients with RCCs have been established many years after the Asian Conference on Tumor Ablation (ACTA) had been held. Given that Western guidelines are difficult to apply to Asian patients due to differences in body habitus, economic status, and insurance systems, the current review sought to establish the first version of the ACTA guidelines for treating a RCC with thermal ablation.

Imaging of Small Renal Masses before and after Thermal Ablation

Thermal ablation of small renal masses is increasingly accepted as an alternative to partial nephrectomy, particularly in patients with multiple comorbidities. Many professional societies support this alternate treatment with updated guidelines. Before performing thermal ablation, it is important to stratify risk and assess technical feasibility by evaluating tumor imaging features such as size, location, and centrality. Routine postablation imaging with CT or MRI is necessary for assessment of residual or recurrent tumor, evidence of complications, or new renal masses outside the ablation zone. The normal spectrum and evolution of findings at CT and MRI include a halo appearance of the ablation zone, ablation zone contraction, and ablation zone calcifications. Tumor recurrence frequently manifests at CT or MRI as new nodular enhancement at the periphery of an expanding ablation zone, although it is normal for the ablation zone to enlarge within the first few months. Recognizing early tumor recurrence is important, as small renal masses are often easily treated with repeat ablations. Potential complications of thermal ablation include vascular injury, urine leak, ureteral stricture, nerve injury, and bowel perforation. The risk of these complications may be related to tumor size and location.^©RSNA, 2019.

Percutaneous radiofrequency ablation of renal cell carcinomas in patients with von Hippel Lindau disease: indications, techniques, complications, and outcomes

Renal cell carcinoma (RCC) in patients with von Hippel Lindau (VHL) disease tends to be multifocal, bilateral, and recur or develop new tumors after removal. These characteristics make treating hereditary RCCs difficult for urologists or radiologists compared to treating a sporadic RCC. Radiofrequency ablation (RFA) is a minimally-invasive treatment for small hereditary RCCs associated with a low complication rate and a minimal decrease in renal function. No RFA guidelines have been established about what to treat and when and how to ablate RCCs in patients with VHL disease. Besides, reports on complications and treatment outcomes in this patient group are rare. The purpose of this review is to discuss the indications, techniques, complications, and outcomes of RFA in treating RCC in patients with VHL disease.

Percutaneous radiofrequency ablation of renal cell carcinomas in patients with von Hippel Lindau disease previously undergoing a radical nephrectomy or repeated nephron-sparing surgery

BACKGROUND

Radiofrequency ablation (RFA) is accepted as a minimally invasive treatment of renal cell carcinoma (RCC). However, RFA is not fully evaluated for treating RCC in patients with von Hippel Lindau (VHL) disease who cannot undergo surgery due to serious postoperative morbidity or mortality.

PURPOSE

To evaluate the role of RFA of RCC in patients with VHL disease previously undergoing renal surgery.

MATERIAL AND METHODS

Percutaneous RFA was performed for treating 14 RCCs in six patients who had undergone radical nephrectomy (n = 3) or repeated nephron-sparing surgery (n = 3). Treatment feasibility, complications, outcome, and the change of renal function were evaluated.

RESULTS

To completely ablate 14 RCCs, 23 ablations during 12 sessions were necessary. Of 14 RCCs, nine were in proximity (<5 mm) to one or more following organs: bowel (n = 4), ureteropelvic junction or pelvis (n = 2), psoas muscle (n = 2), vascular pedicle (n = 1), and pancreas (n = 1). Of 12 sessions, one major complication (pneumothorax) developed in one session (8%). No residual or recurrent tumors were identified at the ablation areas. However, new three solid tumors less than 1 cm in diameter developed during the follow-up period but ablation was withheld until these tumors had grown to more than 1 cm in size. The mean level of serum creatinine increased with 6.4% and the mean estimated glomerular filtration rate decreased by 12.8% after the last ablation compared to those before the initial ablation (P < 0.05).

CONCLUSION

Despite technical difficulties, percutaneous RFA is a promising treatment for VHL patients who cannot undergo surgery because of excellent treatment outcome and minimal change of renal function.

Management and prevention of renal ablative therapy complications

INTRODUCTION

The increasing diagnosis of incidental small renal masses has contributed to energy ablative techniques being increasingly utilized as a primary surgical modality. Despite promise associated with thermal ablation, complications related to both cryoablation (CA) and radiofrequency ablations (RFA) do occur.

METHODS

Contemporary literature on renal ablative procedures (CA and RFA) was reviewed to highlight diagnosis, management, and prevention of complications associated with these procedures.

RESULTS

While morbidity for renal thermal ablation is typically less than extirpative renal surgery, a range of complications of varying severity may exist. Such complications can include sequelae from choice of access site, procedural bleeding, visceral injury, or damage to the collecting system or ipsilateral ureter.

CONCLUSIONS

An understanding of complications secondary to renal ablation is essential for urologists and radiologists to facilitate prompt diagnosis, appropriate management, and future prevention.

Utility of iodinated contrast medium in hydrodissection fluid when performing renal tumor ablation

In 21 patients undergoing percutaneous renal tumor ablation, hydrodissection with use of a mixture of 5% dextrose in water and iodinated contrast medium was performed to prevent thermal injury to adjacent structures. This technique allows for the movement of adjacent organs as well as improved differentiation among the hydrodissection fluid, renal tumor, and adjacent tissues.

Complications of image-guided radiofrequency ablation of renal cell carcinoma: causes, imaging features and prevention methods

Radiofrequency (RF) ablation is an alternative treatment for renal cell carcinoma (RCC) in patients unable to undergo surgery. Although RF ablation has a low complication rate because of its minimally invasive nature, unintended heat may be conducted by several critical organs during ablation procedures, leading to a variety of complications. Major complications that usually require treatment include bowel injury, ureteral injury, massive bleeding and residual or recurrent tumour. Minor complications that may require only observation include pain, haematoma, haematuria, neuromuscular injury, pneumothorax, infarction and inflammatory tract mass. The most common cause of complications is the tumour's proximity to neighbouring organs. In addition, careless electrode manipulation and the patient's comorbidities may also lead to complications. To avoid many of these complications, the distance between the tumour and neighbouring organs should be widened using methods such as changing the patient's position, using the RF electrode as a lever and hydrodissection. Furthermore, carefully manipulating the RF electrode and assessing the patient's general condition help to prevent complications. In this review, we discuss the complications resulting from RF ablation of RCC with an emphasis on causes, imaging features and prevention methods.