Patricia Beemster

Perioperative Morbidity of Laparoscopic Cryoablation of Small Renal Masses with Ultrathin Probes: A European Multicentre Experience

BACKGROUND Low morbidity has been advocated for cryoablation of small renal masses. OBJECTIVES To assess negative perioperative outcomes of laparoscopic renal cryoablation (LRC) with ultrathin cryoprobes and patient, tumour, and operative risk factors for their development. DESIGN, SETTING, AND PARTICIPANTS Prospective collection of data on LRC in five centres. INTERVENTION LRC. MEASUREMENTS Preoperative morbidity was assessed clinically and the American Society of Anaesthesiologists (ASA) score was assigned prospectively. Charlson Comorbidity Index (CCI) and Charlson-Age Comorbidity Index (CACI) scores were retrospectively assigned. Negative outcomes were prospectively recorded and defined as any undesired event during the perioperative period, including complications, with the latter classed according to the Clavien system. Patient, tumour, and operative variables were tested in univariate analysis as risk factors for occurrence of negative outcomes. Significant variables (p<0.05) were entered in a step-forward multivariate logistic regression model to identify independent risk factors for one or more perioperative negative outcomes. The confidence interval was settled at 95%. RESULTS AND LIMITATIONS There were 148 procedures in 144 patients. Median age and tumour size were 70.5 yr (range: 32-87) and 2.6 cm (range: 1.0-5.6), respectively. A laparoscopic approach was used in 145 cases (98%). Median ASA, CCI, and CACI scores were 2 (range: 1-3), 2 (range: 0-7), and 4 (range: 0-11), respectively. Comorbidities were present in 79% of patients. Thirty negative outcomes and 28 complications occurred in 25 (17%) and 23 (15.5%) cases, respectively. Only 20% of all complications were Clavien grade > or = 3. Multivariate analysis showed that tumour size in centimetres, the presence of cardiac conditions, and female gender were independent predictors of negative perioperative outcomes occurrence. Receiver operator characteristic curve confirmed the tumour size cut-off of 3.4 cm as an adequate predictor of negative outcomes. CONCLUSIONS Perioperative negative outcomes and complications occur in 17% and 15.5%, respectively, of cases treated by LRC with multiple ultrathin needles. Most of the complications are Clavien grade 1 or 2. The presence of cardiac conditions, female gender, and tumour size are independent prognostic factors for the occurrence of a perioperative negative outcome.

Follow-up of renal masses after cryosurgery using computed tomography; enhancement patterns and cryolesion size

To describe the characteristics of cryolesions as seen on computed tomography (CT), for size and enhancement patterns, and to assess correlations between these imaging findings and histopathological diagnosis, as in renal cryosurgery the tumour is ablated in situ and the follow‐up is mainly based on imaging.

Laparoscopic renal cryoablation using ultrathin 17-gauge cryoprobes: mid-term oncological and functional results

Study Type – Therapy (case series)

Are there parameters that predict a nondiagnostic biopsy outcome taken during laparoscopic-assisted cryoablation of small renal tumors?

BACKGROUND AND PURPOSE The histopathologic diagnosis of a small renal mass (SRM) that is managed with cryoablation relies on preoperative or intraoperative biopsies. Because a considerable number of these SRMs are benign, accurate diagnosis has prognostic and follow-up implications. The main problem in SRMs is the high rate of nondiagnostic biopsies. Our purpose was to assess whether certain tumor and biopsy characteristics are correlated with a diagnostic biopsy outcome. PATIENTS AND METHODS One hundred tumors that were smaller than 4.5 cm in 94 patients were managed with laparoscopic cryoablation. After dissection of the perirenal fat and identification of the tumor by intra-abdominal ultrasonography, one or more biopsies were obtained before freezing. Using the Student t/Mann Whitney U test, the following parameters were evaluated for predicting biopsy outcome: Tumor size, location, and exophytic part of the tumor, size of the biopsy needle, the number of biopsies taken, and presence of nonenhancing areas compatible with necrosis inside the tumors. Correlations among parameters were assessed using a Spearman correlation or Kruskal-Wallis test. RESULTS Twenty-two (22%) biopsies were nondiagnostic and consisted of normal kidney tissue, connective tissue, fat, fibrosis, necrosis, and/or blood. There were no significant differences in parameters between the diagnostic and nondiagnostic group. There was a positive correlation between tumor size and number of biopsies (P=0.029) and between the presence of nonenhancing areas and both size (P<0.001) and the number of biopsies taken (P<0.001). CONCLUSION No statistical significant correlation was found between biopsy outcome and tumor or biopsy characteristics. More biopsies were taken in larger tumors, and larger tumors contained more nonenhancing areas that were suspect for necrosis.

In Vivo Factors Influencing the Freezing Cycle During Cryoablation of Small Renal Masses

PURPOSE The aim of this study is to present a procedural analysis of the cryoablations performed in our department for small renal tumors and to try to identify clinical parameters or factors that influence the freezing rate during the procedure. PATIENTS AND METHODS We collected all data from the procedures performed in our department until August 2007. Based on the intraoperative biopsy result, we grouped the cases in two groups: renal-cell carcinoma (RCC) and benign. We calculated the freezing rate in both groups and compared them. Finally, we performed a univariate and multivariate analysis to identify clinical parameters that significantly influence the freezing rate. RESULTS A total of 70 cryoablations of small renal tumors in 67 patients were performed during this period. From these, 56 procedures met the inclusion criteria and were analyzed further. The RCC group consisted of 48 cases (39 RCC and 9 lesions with a nondiagnostic biopsy) while 8 formed the benign group. There was no difference in the freezing rate between these two groups. Preoperative creatinine levels above 120 IU, diabetes mellitus, American Society of Anesthesiologists score 3, and location of the tumor at the lower pole were found to increase the freezing rate. The only factor that significantly decreased the freezing rate was the presence of chronic obstructive pulmonary disease. The multivariate analysis showed that the location of the tumor and diabetes mellitus influence more significantly the temperature v time graph. CONCLUSIONS The freezing rate during cryotherapy of small renal tumors is significantly influenced by various clinical factors, while there are no differences in the freezing rate of those proven small malignant tumors and the small benign lesions.

The performance of 17-gauge cryoprobes in vitro.

In cryosurgery it is crucial that the performance of cryoprobes is predictable and constant. In this study we tested the intra- and interneedle variation between 17-gauge cryoprobes in two homogeneous mediums. Also, a multiprobe setup was tested. Cryoprobe performance was defined as the time it takes one cryoprobe to lower the temperature from 0 to −20 °C as measured by four thermosensors each at 3 mm distance from the cryoprobe. In agar eight cryoprobes were tested during six freeze cycles, and in gel four cryoprobes during four freeze cycles; each freeze cycle in a different cup of agar or gel. Using more accurate ‘bare’ thermosensors three cryoprobes were tested in gel during two freeze cycles. A multiprobe configuration with four cryoprobes was tested during two freeze cycles in both agar and gel. Statistical analyses were done using ANOVA for repeated measures. There was no significant intraneedle variation, whereas both in agar and gel there was a significant interneedle variation (p<0.05). Mean performance in gel was better than in agar (p<0.001). Also, there was a significant variation between the four thermosensors (p< 0.001). Using bare thermosensors mean performance was 2.7 times faster compared to measurements by regular thermosensors (p<0.001). In a multiprobe configuration, overall performance seems less variable and more reproducible compared to a single cryoprobe. In conclusion, the performance of cryoprobes differs depending on the medium and measuring device used. Cryoprobes deliver reproducible freeze cycles, although there is variation between different cryoprobes. In a multiprobe configuration performance seems less variable.

Quality of life and perceived pain after laparoscopic-assisted renal cryoablation

PURPOSE Assessing changes in quality of life (QoL) and perceived pain after laparoscopic-assisted cryoablation (LAC) of renal tumors. PATIENTS AND METHODS Data for 57 patients who were treated with LAC were prospectively collected. QoL, divided into various domains, and postoperative pain were assessed using the Medical Outcome Study 36-item Short Form Health Survey (SF-36), the European Organization for Research and Treatment of Cancer QLQ-C30 (EORTC-QLQ-C30), and Visual Analog Scale (VAS). Assessment was performed at baseline and at different time intervals until 1 year after LAC. Using a repeated measures analysis of variance, the influence of the following parameters was evaluated: Time of assessment, age, comorbidity, the occurrence of a complication, and tumor histology. RESULTS SF-36: At baseline, only general health perceptions scored lower compared with the general population. Time of assessment and a complication did not affect QoL. Comorbidity and age >70 years led to a significantly lower QoL. Tumor histology affected general health perceptions. EORTC-QLQ-C30: Time of assessment affected 7 of 15 domains because of lower scores after 2 weeks. Age and comorbidity each negatively influenced five domains. A complication increased three symptoms scores and lowered general health status. Tumor histology significantly altered role functioning. VAS: VAS reached a peak 1 day after LAC, then quickly declined. Patients >70 years had significant higher VAS. CONCLUSIONS QoL of patients who were treated with LAC showed a decrease 2 weeks after surgery but normalized to baseline within 3 months. Age and comorbidities especially affected QoL negatively. The VAS showed a peak 1 day after LAC and then quickly declined.

Contrast-enhanced ultrasound of the kidneys

Several imaging techniques can be used for visualization of the kidneys dependent on the indication. Ultrasound (US), computerized tomography (CT), and magnetic resonance imaging (MRI) are most commonly used. US is a safe, relatively inexpensive, noninvasive, and widely available imaging method. It is therefore often used as a screening tool, especially for nephrolithiasis, hydronephrosis, renal masses, and perirenal processes. Often, in case of an abnormal finding, a CT or MRI follows for more detailed information about the extent, the anatomical landmarks, and eventually surgical treatment planning.