Flexible Nephroscopy, Diagnostic Ureteroscopy for Upper Tract TCC, and Laparoscopic Cryoablation of Renal Tumors

Minimally Invasive Surgery; Endourology

REVIEWING THE LITERATURE Minimally Invasive Surgery • Endourology Flexible Nephroscopy, Diagnostic Ureteroscopy for Upper Tract TCC, and Laparoscopic Cryoablation of Renal Tumors Jonathan L. Giddens, MD, Michael Grasso III, MD New York University School of Medicine New York [Rev Urol. 2000;2(1):19-20, 28] T he goal of endourology and minimally invasive surgery is to advance the field of urology by applying techniques that yield results equal to open operative procedures with less associated morbidity, shorter hospital stays, and prompt return to normal activity. The following recent articles deal with important clinical applications in these fields. The current role of flexible nephroscopy is outlined, the clinical safety of diagnostic ureteroscopy for upper tract transitional cell carcinoma (TCC) is confirmed, and further data supporting the initial investigations into laparoscopic cryoablation of small renal tumors are presented. Expanding Role of Flexible Nephroscopy in the Upper Urinary Tract Beaghler MA, Poon MW, Dushinski JW, Lingeman JE. J Endourol. 1999;13(2):93-97. The authors define and characterize diagnostic and therapeutic applications of the flexible nephroscope in urology. They concentrate on its major clinical applications: • As an adjunct to rigid instruments during primary percutaneous nephrolithotomy (PCNL) • As the primary endoscope to remove residual calculi after primary PCNL in a second-look procedure • As the primary endoscope to treat both renal calculi and other upper urinary tract pathology The features of the flexible nephroscopes available today are also presented. The authors describe their technique, which begins with a nephrostogram. Contrast medium is instilled to delineate the collecting system and all calyces in a search for resid- ual calculi after PCNL. Stones can be removed with a nitinol basket or grasping forceps, manipulated into the renal pelvis with irrigation or a guidewire, or dislodged from a papilla with the tip of the nephroscope. Calyceal stones smaller than 1 cm are fragmented with the holmium:YAG laser and removed. Once all calyces have been cleared, fragments that have been washed into the renal pelvis are cleared with standard rigid endoscopes and ultrasonic lithotripsy. The authors strongly suggest that patients with struvite stones and with residual fragments following primary PCNL undergo second-look flexible nephroscopy. In this series, nephroscopy was performed 48 hours after the initial PCNL. This allows the nephrostomy tract to mature, and thus the procedure can be done without an Amplatz sheath, in a bloodless field, using minimal anesthesia. The decision to perform this at the bedside, in the clinic, or in the operating room is guided by the size of the calculi. For small stones in the lower pole and for morbidly obese patients who have small calculi and are not candidates for other treatments, the flexible nephroscope can be used as the primary endoscope to manage renal calculi percutaneously. A small nephrostomy tract (“miniperc,” 20F–24F) may be used. In addition, the flexible nephroscope obviates the need for special equipment necessary for rigid nephroscopy in the morbidly obese patient. The use of flexible nephroscopes during primary PCNL and in second-look procedures improved the clearance of stone burden without the need for additional access, procedures, or sandwich therapy. In addition, imaging with CT to detect residual fragments following PCNL was frequently unnecessary, since all of the calyces had been carefully inspected. The authors concluded that with the advance- WINTER 2000 REVIEWS IN UROLOGY 19 Endourology continued ments in endoscope and working instrument design, the role of flexible nephroscopy will continue to expand. Laparoscopic Renal Cryoablation: Acute and Long-Term Clinical, Radiographic, and Pathologic Effects in an Animal Model and Application in a Clinical Trial Impact of Diagnostic Ureteroscopy on Long-Term Survival in Patients With Upper Tract Transitional Cell Carcinoma Bishoff JT, Chen RB, Lee BR, et al. J Endourol. 1999;13:233-239. Hendin BN, Streem SB, Levin HS, et al. J Urol. 1999;161:783-785. In this article, the authors review their experience with renal cryosurgery and study the feasibility of laparoscopic delivery. Laparoscopic cryosurgical ablation was performed in a porcine animal model with minimal blood loss. The size of the ice ball, measured intraoperatively using sonography, ranged from 27 mm with a single 5-minute freeze to 41 mm with a 15-minute double freeze. There were dense adhesions to the bowel but no fistula formation in nonretroperitonealized kidneys and minimal adhesions seen with retroperitonealized kidneys. No urinary fistulae were noted postoperatively. Intraoperative ultrasonography showed the ice ball as hypoechoic, with color-flow Doppler demonstrating loss of normal flow characteristics. CT scanning revealed an enhancement defect at 24 hours and 1 week, corresponding to the area of the ice ball, while at 13 weeks, only a nonenhancing defect was seen. At immediate harvest, the cryoprobe sites were reddened and grossly hemorrhagic, with extensive hemorrhage observed microscopically; a sharp border was seen from the freeze zone to the adjacent normal kidney. At 1 week, four distinct zones were seen microscopically: central necrosis, inflammation, hemorrhage, and peripheral fibrosis and regeneration. At 13 weeks, the necrotic tissue apparent at week 1 had been removed, leaving a gross indentation at the lesion site, microscopically appearing as fibrosis. The remainder of the kidney, outside the focal cryoprobe lesions, appeared normal. On the basis of these experimental findings, the authors began a clinical trial in select patients with T1 renal tumors. Eight patients with clinical T1 tumors (average size, 2 cm) underwent laparoscopic cryosurgical ablation of their lesions. A transperitoneal approach was used for the five patients with anterior and medial tumors, and a retroperitoneal approach was used for three patients with posterolaterally placed tumors. Three or four ports were used in each case, with the fourth port placed after the kidney was mobilized to permit accurate placement of either the 3- or 4.8-mm cryosurgical probe. Laparoscopic ultrasonography was used to monitor ice ball formation. A biopsy of each lesion was taken, and then the probe was inserted at the biopsy site into the tumor. A double freeze of 5 minutes or a single 15-minute freeze was used, until the tumor was frozen along with a 0.5- to 1-cm peripheral margin. After freezing, the probe was removed, and hemostasis was secured using absorbable gelatin sponge. The authors review whether preoperative diagnostic ureteroscopy for evaluation of upper tract TCC has an impact on tumor recurrence or survival after open surgical resection. A retrospective review of 96 patients treated with open surgery for upper tract TCC was performed. Patients underwent either total nephroureterectomy with a bladder cuff or distal ureterectomy with a negative proximal margin and with a bladder cuff. Of these patients, 48 had undergone preoperative diagnostic ureteroscopy (study group), while 48 had not (control group). Exclusion criteria included patients in whom upper tract TCC was detected incidentally as a positive distal ureteral margin during radical cystectomy and those in whom upper tract TCC was found as an unexpected finding during pathologic review of a specimen removed for a different indication. Patients with a history of TCC of the bladder documented to be of a higher stage than their upper tract disease were also excluded. Metastases developed in 6 (12.5%) of the study group patients compared with 9 (18.8%) of those in the control group. At 5 years, the probability of metastases-free survival was 0.67 and 0.71, and the probability of overall survival was 0.87 and 0.76, respectively, for the study and control groups. The differences seen in these groups were not statistically significant. Overall, 14 patients (29%) died in each group, and 5 patients (10%) in each group had disease-specific mortality. The authors state that diagnostic ureteroscopy should be part of the standard diagnostic algorithm for evaluation of patients with upper tract urothelial lesions. It permits visual examination, pathologic confirmation, and assessment of tumor volume in these patients. However, during ureteroscopy, pyelovenous, pyelotubular, and pyelolymphatic backflow of irrigation can occur, particularly when high pressures are generated. This study was performed to determine whether ureteroscopy affects tumor progression or survival outcomes. It demonstrated that no adverse long-term effects were associated with diagnostic ureteroscopy in patients with upper tract TCC who have definitive surgery following ureteroscopy. The authors thus have confirmed the clinical safety of ureteroscopy in this setting. continued on page 28 20 REVIEWS IN UROLOGY WINTER 2000