Laparoscopic partial nephrectomy: current status.

Transcription

1 868 international section 20 Arch. Esp. Urol., 55, 7 ( ), 2002 Laparoscopic partial nephrectomy: current status. NORBERTO O. BERNARDO 1 and INDERBIR S. GILL 2. From the Section of Laparoscopic and Minimally Invasive Surgery, Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio. USA. Summary.- OBJECTIVE: Increasingly nephronsparing partial nephrectomy has became widely accepted as a preferred treatment option for the select patient when the adenocarcinoma involves a solitary kidney or poorly functioning contralateral kidney, and in patients with synchronous bilateral tumors. While open partial nephrectomy is currently the standard nephron sparing procedure for treatment of renal tumors, laparoscopic partial nephrectomy has emerged as a potential alternative recently. METHODS: This review seeks a critical assessment of the current status of laparoscopic partial nephrectomy, Address correspondence to: 1 Bernardo, Norberto O. División Urología Hospital de Clínicas "José de San Martín" University of Buenos Aires, Argentina. 2 Gill, Inderbir, S. Section of Laparoscopic and Minimally Invasive Surgery Urological Institute, A-100, The Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, Ohio 44195, USA. Accepted for publication April 1 st, worldwide results and a brief description of energy based in-situ tumor ablation systems. We have duplicated laparoscopicaly, the open surgical techniques. While choice of laparoscopic approach depends upon the surgeon's personal preference, the precise location of the tumor on the kidney is the main factor determining our either retroperitoneal or transperitoneal approach. Hilar clamping reliably achieves a bloodless field, decreases renal turgor and allows surgical precision during tumor excision and control of larger vessels, which represents a real, practical and significant advantage. Precise suture repair currently remains the optimal and most reliable method for sealing a collecting system entry during the course of a laparoscopic partial nephrectomy. With increasing experience, laparoscopic partial nephrectomy can be safely applied to renal tumors that extend deeply, even upto the renal sinus. CONCLUSIONS: As more data emerges and the technical success rates of laparoscopic partial nephrectomy improve this minimally invasive technique will gain a wider role in the treatment of select renal cell carcinomas. Keywords: Laparoscopy. Nephrectomty. Kidney. Resumen.- OBJETIVO: La cirugía conservadora renal se ha convertido en una opción terapéutica ampliamente aceptada cuando un adenocarcinoma involucra un riñón solitario o una pobre función renal contralateral y en pacientes con tumores sincrónicos bilaterales. Mientras la cirugía conservadora renal a cielo abierto es el procedimiento standard para el tratamiento de los tumores renales, la nefrectomía parcial laparoscópica ha emergido recientemente como una alternativa potencial. MÉTODOS/RESULTADOS: Esta revisión busca una visión crítica del estado actual de la nefrectomía parcial

2 LAPAROSCOPIC PARTIAL NEPHRECTOMY: CURRENT STATUS 869 laparoscópica con los resultados mundiales y una descripción breve de los sistemas de ablación in-situ con distintas fuentes de energía. Hemos duplicado por vía laparoscópica las técnicas a cielo abierto. Mientras el abordaje laparoscópico depende de la preferencia del cirujano, la localización precisa del tumor dentro del riñón es el factor principal determinante nuestro abordaje retroperitoneal o transperitoneal. El clampeo del hilio logra un campo exangüe, disminuye la turgencia renal y permite precisión quirúrgica durante la resección tumoral y el control de los vasos sanguíneos, representando una ventaja real, práctica y significativa. La sutura precisa representa el método más confiable de reparación de la apertura del sistema colector durante el curso de una nefrectomía parcial laparoscópica. Con la experiencia creciente la nefrectomía parcial laparoscópica puede ser aplicada con seguridad en tumores que penetran profundamente involucrando el seno renal. CONCLUSIONES: Con la aparición de más casuística y con mejores índices de éxito de la nefrectomía parcial laparoscópica, esta técnica ganará un rol más amplio en el tratamiento conservador de carcinomas de células renales. Palabras clave: Laparoscopia. Nefrectomía. Riñón. INTRODUCTION Renal cell carcinoma is the third most common urological malignancy (1). Its detection rate has increased by 15% to 20% because of the use of newer and more sophisticated medical imaging techniques (2). Currently, approximately 40% of renal tumors are discovered incidentally often when their size is <4cm. Notwithstanding recent advances in our understanding of biology and genetics of this disease (3, 4 ), surgical excision remains the mainstay of curative treatment for renal cell carcinoma (5). Although radical nephrectomy remains the gold standard for the larger tumors, increasingly nephronsparing partial nephrectomy has became widely accepted as a preferred treatment option for the select patient when the adenocarcinoma involves a solitary kidney or poorly functioning contralateral kidney, and in patients with synchronous bilateral tumors (6). More recently, the experience at the Cleveland Clinic and other centers has advocated expanding the indications for nephron-sparing surgery to include patients with a small ( 4cm), incidentally-diagnosed renal cancer situated in an anatomically favorable location even in the presence of a normal opposite kidney (7, 8, 9). Recently, new methods of treatment have been developed to allow for a minimally invasive approach for urological diseases. Initially, laparoscopic techniques were restricted to simple nephrectomy for benign diseases. Since Clayman's first total nephrectomy in 1990 (10), urological laparoscopic surgery has gained in popularity and expanded in scope. Advanced procedures, such as adrenalectomy (11), live donor nephrectomy (12), and recently radical prostatectomy (13), enterocystoplasty (14) and radical cystectomy with urinary diversion (15) have been performed by laparoscopic techniques. While open partial nephrectomy is currently the standard nephron sparing procedure for treatment of renal tumors, laparoscopic partial nephrectomy has emerged as a potential alternative recently.(16, 17, 18, 19). This review seeks a critical assessment of the current status of laparoscopic partial nephrectomy. Specifically, a detailed analysis of the following aspects will be approached: Indications and contraindications, laparoscopic approaches, renal hilar control, renal hypothermia, intraoperative ultrasonography, methods for parenchymal resection and hemostasis, techniques for renal collecting system closure, role of handassistance, worldwide results and a brief description of energy based in-situ tumor ablation systems. INDICATIONS Laparoscopic partial nephrectomy has been described previously. Initially explored in the animal model by McDougall and associates in 1993 (20). Winfield et al reported the initial clinical transperitoneal laparoscopic partial nephrectomy (21), and Gill et al reported the initial retroperitoneal laparoscopic partial nephrectomy (22). Subsequently, a few select centers have published their early experiences with laparoscopic partial nephrectomy. Recently, the 4-cm cut-off size of the lesion has been established as important selection criterion for substratification for nephron sparing surgery in a series of 485 patients (23). At the Cleveland Clinic we initially offered

3 870 laparocopic partial nephrectomy to select patients with a small, predominantly exophytic tumor, which was located at a distance from the pelvicalyceal system. With increasing experience we currently offer laparoscopic partial nephrectomy to select candidates for nephron-sparing surgery who have a renal tumor upto 7 cm in size, even if it deeply invades the renal parenchyma upto the renal sinus and the collecting system. In our current experience with over 115 laparoscopic partial nephrectomies, we have tackled tumors requiring upto a 60% heminephrectomy and even performed laparoscopic partial nephrectomy for tumor in a solitary kidney in approximately 10 patients. At this writing our current contraindication for laparoscopic partial nephrectomy include multifocal renal tumors and the occasional completely-intrarenal tumor located deeply within the mid kidney. Clinical stage of the renal tumors was ct 1-2 N 0 M0 (19). Imperative indications were present in 48% of our patients because of either a compromised contralateral kidney or a tumor in a solitary kidney. Elective indications were present in 52% of our patients. APPROACH While choice of laparoscopic approach depends upon the surgeon's personal preference (24), the precise location of the tumor on the kidney is the main factor determining our approach (17, 19). If the tumor is located posterior or posterolateral, retroperitoneoscopy offers direct access. If the tumor is located anterior, anterolateral, lateral or at the apex of the upper pole, transperitoneal laparoscopy provides a better approach. We routinely insert by cystoscopy a 5 Fr openended ureteral catheter over a glide wire into the renal pelvis at the beginning of the surgery to allow intraoperative instillation of indigo carmine dye to evaluate pelvicalyceal entry. Early in our experience the catheter was inserted only in selected patients with a larger tumor extending towards the collecting system, wherein achievement of a safe surgical margin would necessitate a deeper resection. However, since 1 patient with an almost completely exophytic tumor developed a small asymptomatic, incidentally-detected urinoma postoperatively, we now routinely perform retrograde injection of methylene blue via a ureteral catheter in all patients. Transperitoneal approach The patient is secured to the table in a 45-degree lateral position and pneumoperitoneum is achieved. A 4 port technique is used with an additional 2mm lateral port for retraction purposes. Identification and lateral retraction of the ureter is crucial to avoid injury. Once the renal hilum is identified, it is mobilized in bloc (without dissection between vein and artery) avoiding disruption of any lumbar vessel along its posterior aspect (19). A laparoscopic Satinsky clamp is test positioned across the entire renal hilum. The kidney is mobilized to allow inspection of the renal surface, leaving intact the perirenal fat overlying the tumor. A laparoscopic flexible, color Doppler probe is introduced through a 10/12mm port and positioned in contact with the surface of the kidney, offering detailed realtime information about tumor size, depth of tumor extension into the parenchyma, distance from the collecting system, location of vessels around the periphery of the tumor and existence of any satellite tumor in the remainder of the kidney. With ultrasonographic guidance, the proposed line of incision is scored circumferentially around the tumor with a J-hook electrocautery, maintaining a generous margin from the tumor edge. Retroperitoneal The patient is placed in the 90 degree full flank lateral decubitus position with the table flexed to increase the distance between the 12 th rib and the iliac crest (25). Following retroperitoneal balloon dilation and placement of 3 ports, the renal artery and vein are dissected individually. One laparoscopic bulldog clamp is placed sequentially each on the renal artery and vein. Because of the limited room in the retroperitoneum, we do not use the Satinsky clamp for hilar control. However, similar to the transperitoneal approach, ultrasonography is performed routinely in order to define the line of parenchymal incision. RENAL HILAR CONTROL Laparoscopic partial nephrectomy is a technically challenging operation because of the risk of significant intraoperative bleeding during incision of the renal parenchyma.

4 LAPAROSCOPIC PARTIAL NEPHRECTOMY: CURRENT STATUS 871 TABLE I.- Demographic and pathological data o of the initial 50 cases Adapted from Gill et al., J. Urol., 167: 469, Several series report no control of the renal artery in patients undergoing laparoscopic wedge resection for a small renal tumor (21, 26, 27, 28). Harmon et al dissected free the renal vessels to the point at which their rapid transection with the laparoscopic stapler could be accomplished subsequently if necessary (29). However, such a maneuver would imply nephrectomy instead of the proposed more conservative partial nephrectomy. Hoznek et al dissected entirely the pedicle in 2 cases where temporary arrest of renal perfusion was planned and applied a non-traumatic vascular clamp en bloc to the pedicle only for short periods if bleeding could not be controlled with bipolar coagulation alone (18) (Table I). Rassweiler et al reported a multicentric European experience wherein dissection and placement of a loop around the renal artery in all cases. However, they do not describe if that loop has been utilized for temporary ischemia. In fact, 50% of their conversions to open surgery occurred because of significant intraoperative bleeding (24). At the Cleveland Clinic more than 1,000 open partial nephrectomies have been performed (30), establishing clear-cut technical guidelines for this procedure. Since 1999, we set out to develop a laparoscopic technique of partial nephrectomy in such a manner as to mirror the established open principles. (Table I). For the transperitoneal approach a Satinsky clamp is routinely positioned across the entire hilum, while for the retroperitoneal approach, because of the limited room we do not use Satinsky clamp, opting instead for individual laparoscopic bulldog clamps sequentially placed each on the renal artery and renal vein, respectively. Thus, hilar clamping reliably achieves a bloodless field, decreases renal turgor and allows surgical precision during tumor excision and control of larger vessels, which represents a real, practical and significant advantage. We believe that a "bloodless field" is a primary requirement during every partial nephrectomy, open or laparoscopic. Our mean warm ischemia time was 23 minutes (19). Based on experimental evidence (31, 32) we have long believed that intermittent unclamping of the renal artery to allow periodic re-circulation of the ischemic renal parenchyma could potentially be more detrimental to renal function than continuous renal arterial occlusion because of re-perfusion injury caused by release of free oxygen radicals. RENAL HYPOTHERMIA In the setting of a broad based mass or one located near the mid portion of the kidney, or in cases of extensive entry into the collecting system, where a bloodless field is needed to suture-repair the defect accurately, a longer warm ischemia time is necessary. If the anticipated duration of ischemia is greater than 30 minutes, renal hypothermia should be achieved at the outset to achieve persistent cold ischemia (19). Currently, available techniques for clinical laparoscopic hypothermia require refinement. We are developing a mechanism for more efficient laparoscopic delivery of fine ice slush into the abdomen in our laboratory at the Cleveland Clinic. INTRAOPERATIVE ULTRASONOGRAPHY The laparoscopic ultrasonic probe is a 7.5 MHz. 90- degree mechanical sector scanning system, with a

5 872 straight end-viewing probe and a side-viewing probe, which passes down a 12 mm. laparoscopic port and usually, but not necessarily, requires the hands-on involvement of an expert ultrasonographer. Detailed real-time ultrasonographic information is critically important to achieve pertinent information about tumor size, tumor depth/extension into the parenchyma, distance from the adjacent calyx and renal sinus, location of any surrounding vasculature at the periphery of the tumor, and presence of any satellite tumors in the remainder of the kidney. Such intraoperative information gives the laparoscopic surgeon an excellent 3-D concept about planning the line of parenchymal incision. With ultrasonographic guidance, the proposed line of parenchymal incision is circumferencially scored with an electrocautery J-hook, maintaining a generous margin around the tumor (19). We believe that this important information is critical for reliable and routine performance of laparoscopic partial nephrectomy However, most series of laparoscopic partial nephrectomy do not report use of perform intraoperative ultrasonography (Table II). METHODS FOR PARENCHYMAL RESECTION AND HEMOSTASIS Janeschtek and associates have almost exclusively used bipolar coagulation forceps for simultaneous dissection and hemostasis (26). A dissecting sponge was used providing satisfactory hemostasis through mechanical compression. Following tumor excision and coagulation the cut surface was cauterized with argon beam and sealed it with fibrin glue. In the last procedure of their series they used an ultrasonic scalpel, which occludes small vessels by denaturation of proteins allowing simultaneous dissection and coagulation by high frequency through (55,000 Hz.) longitudinal oscillations. Harmon at al used laparoscopic coagulating shears (Harmonic Scalpel, Ethicon Endosurgery, Cincinnati, Ohio) for resecting tumors smaller than 3.5 cm with a 1.0-cm normal parenchymal margin previously marked at the kidney surface with argon beam coagulator (29). This device was also used at any time the shears failed to control parenchymal bleeding. In a porcine model the harmonic scalpel was inadequate for controlling TABLE II.- Intraoperative data from institutional experience with laparoscopic partial nephrectomy: worldwide N/E: NOT EVALUATED N/A: DATA NOT AVAILABLE Bi: bipolar coag. AB: ARGON BEAM COAGULATOR HS: HARMONIC SCALPEL RF: radiofrequency MW: microwave coagulator Ho: hook CS:COLD SHEARS EC: electrocautery FG: FIBRIN GLUE S: SUTURES

6 LAPAROSCOPIC PARTIAL NEPHRECTOMY: CURRENT STATUS 873 parenchymal bleeding during partial nephrectomy such that the authors stated that its use is not recommended during heminephrectomy (33). Our clinical experience corroborates these experimental findings (19), and we believe that the harmonic scalpel could be inadequate as the sole hemostatic agent for controlling the major hemorrhage that would certainly ensure from the interlobar during a substantive partial nephrectomy. Hoznek and collaborators have also used bipolar coagulation for step-by-step sectioning and coagulation of the parenchyma. A non-traumatic vascular clamp was applied for less than 10 minutes when bleeding could not be controlled by bipolar coagulation alone (18). The bipolar electrocautery, in addition to being inadequate for reliable hemostasis, also chars the tissue, which then adheres to it, resulting in suboptimal visualization of the tumor bed and an inexact line of parenchymal incision. In 1995, Gill et al first devised a laparoscopic renal tourniquet for circumferentialy compressing the renal parenchyma to control the hemorrhage from the intrarenal vessels during a partial nephrectomy (34). Subsequently, Cadeddu and Corwin have used in one single patient a ¼-inch wide, 10-inch long plastic cable tie laparoscopically cinched around the upper pole of the kidney to excise a polar tumor (35). Argon beam coagulator and fibrin glue with oxidized cellulose were employed to seal the parenchymal surface and collecting system. Several investigators found these renal parenchymal tourniquets to be reasonably effective in the experimental porcine model (36). However, it is abundantly clear that these porcine findings can not be extrapolated to the clinical situation. In our experience, the adequacy of hemostasis thus achieved in the human kidney has been unreliable, with persistent pulsatile arterial bleeding evident from the cut edge of the kidney despite application of the tourniquet. In addition, such devices cannot be used for tumors in the mid kidney. Winfield and associates have used a 5mm. electrocautery blade to incise through the parenchyma followed closely by argon coagulator which then extensively fulgurated the raw parenchymal surface (21). The argon beam coagulator, although an excellent tool for superficial surface coagulation of minor oozing, is inadequate for controlling pulsatile arterial hemorrhage from the larger intrarenal vessels. Yoshimura and associates performed microwave tissue coagulation with a needle type monopolar applicator (28). The line of incision was marked circumferentially at 1 cm. from the tumor edge with electrocautery and the punctures were done 5mm apart from each other. The coagulations were performed at 70 W for 45 seconds per session and the tumor was excised with scissors by cutting the mid portion of the coagulated zone. An argon beam coagulator and oxidized cellulose were applied to achieve complete hemostasis on the cut surface of the kidney. Wolf and associates using hand assistance, performed dissection and coagulation with bipolar forceps and then covered the cut surface with gelatin sponge soaked with fibrin glue, which was held by finger pressure for 10 minutes (37). However, in our opinion, use of hand assistance compromises some of the benefits of minimally invasive surgery. Gettman et al reported the use of a radiofrequency probe inserted percutaneously into the lesion under laparoscopic visualization and deployed to coagulate a spherical area including both tumor and margin of normal parenchyma (27). At the conclusion of radiofrequency the probe was withdrawn and the lesion was excised along with a 0.5 to 1.0 cm. margin of normal parenchyma using laparoscopic scissors (Table II). At the Cleveland Clinic, we have duplicated the open surgical techniques using the J-hook monopolar electrocautery to initiate the renal parenchymal incision along the previously scored line of resection (19). The tumor is elevated from the tumor bed by placing counter traction with the suction cannula, which also simultaneously aspirates the blood, therefore keeping a clear operative field. Excision of the tumor is performed using a cold endoshears to perform cold cutting of the deep renal parenchyma. A mental note is made of the location of any major transected intrarrenal vessels, which will be controlled with specific figureof-8 stitches. The magnification provided by the laparoscope, combined with the bloodless field afforded by the clamped hilum ensures that the line of resection maintains approximately a 0.5 cm. margin of healthy tissue around the tumor. If achievement of such a margin requires entry into the collecting system, the targeted calyx or renal pelvis in incised sharply with endoshears without electrocautery, so as to avoid thermal damage to the collecting system which may potentially compromise its subsequent healing, thus leading to a urinary fistula. The excised tumor is

7 874 TABLE III.- Laparoscopic partial nephrectomy with pelvi-caliceal suture repair: demographic and tumor data. The Cleveland Clinic Experience (38) Adapted from Desai et al, J. Urol. In press immediately entrapped within an Endocatch bag and positioned within the abdomen away from the operative field. TECHNIQUES FOR RENAL COLLECTING SYSTEM CLOSURE Initial reports of laparoscopic partial nephrectomy included highly select patients with a small, peripheral, predominantly exophytic, favourably located renal tumor without significant intraparenchymal extension. Such tumors can be safely excised without entering into the pelvicalyceal system. In the Cleveland Clinic experience, only 8% of the initial laparoscopic partial nephrectomies involved the collecting system entry during tumor excision. However, with increasing experience, we reported the application of laparoscopic partial nephrectomy to include tumors with more extensive intrarenal extension, therefore requiring sharp access into the pelvi-calyceal system to reensure adequate tumor resection (19). As such, 64% of our subsequent laparoscopic partial nephrectomies necessitated excision of the adjacent calyx and part of the collecting system (38) (Table III). Precise intraoperative identification of collecting system entry during a laparoscopic partial nephrectomy is critically important. We have employed retrograde

8 LAPAROSCOPIC PARTIAL NEPHRECTOMY: CURRENT STATUS 875 injection of diluted indigo carmine dye through a preoperative by inserted ureteral catheter routinely in all patients undergoing partial nephrectomy for this purpose (19). Renal hilar vascular control is an essential and important pre-requisite for performing a precise and confident excision of a renal tumor that is broad based in the renal parenchyma and approaches the collecting system. By reducing renal parenchymal turgor and providing a clear bloodless field, hilar occlusion creates the intraoperative conditions that are essential for delicate repair of the collecting system and precise placement of specific figure-of-8 stitches to occlude the transected major intrarenal blood vessels. While alternative hemostatic methods to renal hilar control such as manual compression (37), cable-tie devices (35), or resection using hemostatic energy sources may have a limited role in certain superficial (29), largely exophytic tumors, at this writing, these techniques are clearly inadequate when contemplating significant resections extending into the central sinus. Desai et al have employed pelvi-calyceal suture repair in 27 cases with documented entry into the collecting system (38) (Table IV). There was no obvious postoperative urine leak in any of the 27 patients undergoing pelvi-calyceal suture repair. Other authors have reported alternative techniques for renal collecting system closure after laparoscopic partial nephrectomy. TABLE IV.- Laparoscopic partial nephrectomy with pelvi-calyceal suture repair. intraoperative and postoperative data (38) Adapted from Desai et al, J. Urol. In press.

9 876 TABLE V.- Reported perioperative complications and outcome of patients who underwent laparoscopic partial nephrectomy: worldwide N/E: NOT EVALUATED N/A: DATA NOT AVAILABLE Hoznek et al described the use of oxidized regenerated cellulose mesh impregnated with gelatin resorcinol formaldehyde glue to seal the renal resection bed in 7 laparoscopic partial nephrectomies. Urinoma formation resulted in one patient even with insertion of double- J stent (18). Rassweiler reported from a European multiinstitutional experience of 53 patients undergoing laparoscopic partial nephrectomy with 5 cases (9.4%) of postoperative urinoma formation requiring reintervention (24). However, they employed a combination of alternative methods to seal the renal resection bed including fibrin impregnated hemostatic gauze or heat activated tissue adhesive. These data suggest that precise suture repair currently remains the optimal and most reliable method for sealing a collecting system entry during the course of a laparoscopic partial nephrectomy. Only, when such technical ability to perform precise, time-efficient suture-reconstruction under carefully controlled conditions is demonstrated, can laparoscopic partial nephrectomy hope to emulate open surgery in terms of operative indications, breadth and extension of application, and surgical outcomes. Laparoscopic partial nephrectomy with pelvicalyceal suture repair is associated with longer warm ischemia time (38). Clearly, the price of renal hilar clamping is potential warm ischemic damage. Then, facility with expedient laparoscopic suturing is critical, such that warm ischemia does not exceed 30 minutes. Desai et al from the Cleveland Clinic reported a mean warm ischemia time of 30.2 ± 5.4 min for patients undergoing pelvi-calyceal repair. Of note, no renal unit in this study suffered significant irreversible renal damage as a result of warm ischemia. ROLE OF HAND-ASSISTANCE Laparoscopic partial nephrectomy has also been reported using hand assistance in 10 selected patients (37). After inserting the hand in the peritoneal cavity the laparoscopic ultrasound was placed through another port in order to determine tumor depth and surrounding vasculature, the collecting system and additional tumors. To obtain hemostasis, the mass of sponge soaked with fibrin glue was pressed down on the resection site with one finger for 10 minutes to assist

10 LAPAROSCOPIC PARTIAL NEPHRECTOMY: CURRENT STATUS 877 in hemostasis and then laparoscopic argon beam coagulator was used to seal the edges of the sponge. Furthermore, the greater blood loss found in the handassisted group was explained by the lack of vascular clamping. Stifelman and associates performed 9 handassisted partial nephrectomies using Harmonic Scalpel for tumor excision in conjunction with the argon beam coagulator (39). They used different hemostatic agents, including surgicel, Avitene, and fibrin-soaked Gelfoam activated by thrombin. Although a hand may provide effective parenchymal compression during excision of certain small, superficial tumors, the 7-cm plus mid abdominal incision needed for hand insertion may obviate some benefits of a minimally invasive approach. Further, in our opinion, the hemostasis so achieved will be inadequate for allowing performance of a substantive partial nephrectomy. RESULTS As more data emerges and the technical success rates of laparoscopic partial nephrectomy improve this minimally invasive technique will gain a wider role in the treatment of select, stage T1 renal cell carcinomas. (Table V). A number of technical complications specific to laparoscopic partial nephrectomy have been described. Urinary fistula is the most is the most common renal related complication after nephron sparing surgery. The technical factors for preventing this complication are described previously. The overall re-operative rate after laparoscopic partial nephrectomy remains low in most series (16, 24). Careful intra-operative attention to hemostasis and precise reconstruction of the remnant is mandatory to avoid complications. Differently than many early series of open partial nephrectomy (40, 41, 42), where the procedure was done in high-risk patients in which nephron-sparing surgery was the only alternative to renal replacement therapy, laparoscopic partial nephrectomy has been done mainly in elective cases. Recently, Herr and associates reported 97% cancer-free survival in 70 patients with tumors with a main size of 3cm, evaluating 10-year results of elective open partial nephrectomy in the setting of a normal contralateral kidney (43). The follow-up of laparoscopic partial nephrectomy is still short in the results reported in the literature since the first procedures were done for the treatment of renal tumors (44). However, the summarized results published by Fergany and associates show long-term outcome data for tumors 4 cm. or less with specific survival of 98% at 5 years and 92% at 10 years (45). Most of the series confirm that tumor stage and size remain the most important prognosis indicators determining outcome after nephron sparing surgery (46). The position of the tumor does not play an important biological role for determining cancer specific outcome. Mainly in laparoscopic surgery, central or peripheral tumor location is a relevant technical consideration affecting the indication of the surgery as it is seen in most of the series (16, 26, 29). However, in the experience published by Desai and associates 42% of the patients required pelvi-calyceal suture rapair, since the mean intrarenal extension was 1.5 cm. (38). This technique duplicating the principles of open surgery showed a lesser incidence of urinary leakage than similar patients approached with open surgery. There are no current published reports comparing laparoscopic partial nephrectomy with open nephronsparing surgery (47). The possibility of local tumor recurrence after nephron sparing surgery may be due to incomplete resection of the primary tumor, occult multicentric disease, or the development of a new primary or metastatic focus of renal cell carcinoma in the renal remnant. Technical considerations to avoid incomplete resection, including intraoperative ultrasonography have been reviewed. Surprisingly, a few series point out the importance of laparoscopic ultrasound (18, 21, 37, 38). Is known the low risk of multifocal lesions (5%) when the primary tumor is 4 cm. or less. However, the significant information offered by this technology is important in order to plan safely the amount of resected renal tissue. ENERGY BASED IN-SITU TUMOR ABLATION SYSTEMS. Although the long-term cancer-cure rates and functional efficacy of partial nephrectomy are well documented (6) the procedure itself is associated with potential morbidity, which should be avoided in highrisk patients. With the increasing application of

11 878 minimally invasive surgery, experimental open, percutaneous, and laparoscopic cryoablation has been successfully investigated in the laboratory as clinically (48, 49, 50, 51). Cryosurgery aims to ablate a comparable, predetermined volume of tissue as would have been excised in the event that a conventional surgical procedure had been performed Critical denominators for successful visceral cryosurgery include rapid freezing, slow thawing, and repetition of the freezethaw cycle (52). Thus, the diseased tissue, with an adjacent margin of healthy parenchyma is frozen in situ. Since September 1997 laparoscopic cryoablation has been performed for over 70 patients at the Cleveland Clinic. Hospital stay averaged 1.7 days. To date, 45 patients have undergone a CT-guided needle biopsy of the cryoablated tumor at a follow-up of 3-6 months postoperatively. Histopathology revealed evidence of residual cancer in 1 patient, who subsequently underwent a laparoscopic radical nephrectomy (53). Other alternatives include the percutaneous interstitial laser, thermorods, and radio-frequency or photon radiation therapy (54, 55, 56). These techniques have been applied for the treatment of benign prostatic hyperplasia or prostate cancer for anecdotal palliative applications. The ideal method to treat a small renal tumor would be noninvasive, such the use of extracorporeal highintensity focal ultrasound (HIFU). Recently, a different energy source and an applicator of focused ultrasound has been developed in Germany (57). Determining exactly when during the treatment the entire carcinoma has been destroyed is still the main problem when using all of these technologies. CONCLUSIONS Laparoscopic partial nephrectomy is emerging as an attractive minimally-invasive nephron-sparing option for management of select renal tumors. With increasing experience, laparoscopic partial nephrectomy can be safely applied to renal tumors that extend deeply, even upto the renal sinus. Collecting system entry created during the course of laparoscopic partial nephrectomies can be effectively and expeditiously managed by laparoscopic freehand suture repair without increasing the incidence of perioperative complications or morbidity of this minimally invasive approach. Only when such technical ability to perform time-efficient suture reconstruction under carefully controled conditions is demonstrated, can laparoscopic partial nephrectomy hope to emulate open surgery. This operation should be performed only in highly specialized centers. For the confident development of a reliable and reproducible technique of laparoscopic partial nephrectomy, time-tested open surgical principles should be respected. REFERENCES AND RECOMMENDED READING (*of special interest, **of outstanding interest) 1. BORING, C.; SQUIRES, T., TONG, T. et al.: "Cancer statistics." 1994.CA, 44:7, WUNDERLICH, H.; SCHUMANN, S.; JANITZKY, V. et al.: "Increase of renal cell carcinoma incidence in Central Europe." Eur. Urol., 33:538, FINKE, J.; SALVUCCI KIERSTEAD, L.; RANIERI, E. et al.: "Immunologic response to renal cell carcinoma." In: Renal Cell Carcinoma Edited by R. M. Bukowski and A. C. Novick. Totowa, New Jersey: Humana Press Inc., chap. 3, pp , ENQUIST, E.; ZAMBRANO, N.; ZBAR, B. et al.: "Molecular genetics of renal cell carcinoma." In: Renal Cell Carcinoma Edited by R. M. Bukowski and A. C. Novick. Totowa, New Jersey: Humana Press Inc., chap. 5, pp , ROBSON, C.J.; CHURCHILL, B. and ANDERSON, W.: "The results of radical nephrectomy for renal cell carcinoma." J. Urol., 101: 297, *6. LICHT, M.R. and NOVICK, A.C.: "Nephron sparing surgery for renal cell carcinoma." J. Urol., 149: 1, **7. LICHT, M.R.; NOVICK, A.C. and GOORMASTIC, M.: "Nephron sparing surgery in incidental versus suspected renal cell carcinoma." J. Urol., 152: 39, MORGAN, W.R. and ZINCKE, H.: "Progression and survival after renal conserving surgery of renal cell carcinoma: experience in 104 patients and extended follow-up." J. Urol., 144: 825, STEINBACH, F.; STOCKLE, M.; MULLER J.W. et al.: "Conservative surgery of renal cell tumors in 140 patients: 21 years of experience." J. Urol., 148: 24, CLAYMAN, R.V.; KAVOUSSI, L.R.; SOPER, N.J. et al.: "Laparoscopic nephrectomy: initial case report." J. Urol., 146: 278, GILL, I.S.; HOBART, M.G.; SCHWEIZER, D. et al.: "Outpatient adrenalectomy." J. Urol., 163: 717, RATNER, L.E.; CISECK, L.J.; MOORE, R.G. et al.: "Laparoscopic live donor nephrectomy." Transplantation, 60: 1047, GUILLONNEAU, B. and VALLANCIEN, G.:

12 LAPAROSCOPIC PARTIAL NEPHRECTOMY: CURRENT STATUS 879 "Laparoscopic radical prostatectomy: the Montsouris Experience." J. Urol., 163: 418, GILL, I.S.; RACKLEY, R.R.; MERANEY, A.M. et al.: "Laparoscopic enterocystoplasty. Urology, 55: 178, GILL, I.S.; FERGANY, A.; KLEIN, E.A. et al.: "Laparoscopic radical cystoprostatectomy with ileal conduit performed completely intracorporeally: the initial 2 cases." Urology, 56: 26, McDOUGALL, E.M.; ELBAHNASY, A.M. and CLAYMAN, R.V.: "Laparoscopic wedge resection and partial nephrectomy-the Washington University experience and review of literature." J. Soc. Laparoendosc. Surg., 2: 15, *17. JANETSCHEK, G.; JESCHKE, K.; PESCHEL, R. et al.: "Laparoscopic surgery for stage 1 renal cell carcinoma: radical nephrectomy and wedge resection." Eur. Urol., 38: 131, *18. HOZNEK, A.; SALOMON, L.; ANTIPHON, P. et al.: "Partial nephrectomy with retroperitoneal laparoscopy." J. Urol., 162: 1922, **19. GILL, I.S.; DESAI, M.M.; KAOUK, J.H. et al.: "Laparoscopic partial nephrectomy for renal tumor: duplicating open surgical techniques." J. Urol., 167: 469, McDOUGAL, E.M.; CLAYMAN, R.V.; CHANDOKE, P.S. et al.: "Laparoscopic partial nephrectomy in the pig model." J. Urol., 149: 1633, WINFIELD, H.N.; DONOVAN, J.F.; GODET, A.S. et al.: "Laparoscopic partial nephrectomy: initial case report for benign disease." J. Endourol., 7: 521, GILL, I.S.; DELWORTH, M.G. and MUNCH, L.C.: "Laparoscopic retroperitoneal partial nephrectomy." J. Urol., 152: 1539, *23. HAFEZ, K.S.; FERGANY, A.F. and NOVICK, A.C.: "Nephron sparing surgery for localized renal cell carcinoma: impact of tumor size on patient survival, tumor recurrence and TNM staging." J. Urol., 162: 1930, **24. RASSWEILER, J.J.; ABBOU, C.; JANESTCHEK, G. et al.: "Laparoscopic partial nephrectomy. The European experience." Urol. Clin. North Am., 27: 721, GILL, I.S.: "Retroperitoneal laparoscopic nephrectomy." Urol. Clin. North Am., 25: 343,1998. *26. JANETSCHEK, G.; DAFFNER, P.; PESCHEL, R. et al.: "Laparoscopic nephron sparing surgery for small renal cell carcinoma." J. Urol., 159: 1152, GETTMAN, M.T.; BISHOFF, J.T.; SU, L.M. et al.: "Hemostatic laparoscopic partial nephrectomy: initial experience with the radiofrequency coagulation-assisted technique." Urology, 58: 1, 8, YOSHIMURA, K.; OKUBO, K.; ICHIOKA, K. et al.: "Laparoscopic partial nephrectomy with a microwave tissue coagulator for small renal tumor." J. Urol., 165: 1893, HARMON, W.J.; KAVOUSSI, L.R. and BISHOFF, J.T.: "Laparoscopic nephron-sparing surgery for solid renal masses using the ultrasonic shears." Urology, 56: 5, 754, NOVICK, A.C.: Personal communication. March of McLAUGHLIN, G.A.,;HEAD, M.R. and TYRELL, I.M.: "An evaluation of techniques used for production of temporary renal ischemia." Br. J. Urol., 50: 371, WILSON, D.H.; BARTON, B.B.; PARRY, W.L. et al.: "Effects of intermittent versus continuous renal arterial occlusion on hemodynamics and function of the kidney." Invest. Urol., 8: 507, JACKMAN, S. V.; CADDEDU, J.A.; CHEN, R.N. et al.: "Utility of the harmonic scalpel for laparoscopic partial nephrectomy." J. Endourol., 12: 441, GILL, I.S.; MUNCH, LL.C.; CLAYMAN, R.V. et al.: "A new renal tourniquet for open and laparoscopic partial nephrectomy." J. Urol., 154: 1113, CADEDDU, J.A. and CORWIN, T.S.: "Cable tie compression to facilitate laparoscopic partial nephrectomy." J. Urol., 165: 177, ELASHRY, O.M.; WOLF, J.S. Jr.; RAYALA, H.J. et al.: "Recent advances in laparoscopic partial nephrectomy: comparative study of electrosurgical snare electrode and ultrasound dissection." J. Endourol., 11: 15, *37. WOLF, J.S.; SEIFMAN, B.D. and MONTIE, J.E.: "Nephron sparing surgery for suspected malignancy: open surgery compared to laparoscopy with selective use of hand assistance." J. Urol., 163: 1659, DESAI, M.M.; GILL, I.S.; KAOUK, J.H. et al.: "Laparoscopic partial nephrectomy with suture repair of the pelvi-caliceal system." J. Urol., in press. 39. STIFELMAN, M.D.; SOSA, R.E.; NAKADA, S.Y. et al.: "Hand-assisted laparoscopic partial nephrectomy." J. Endourol., 15: 161, VERMOOTEN, V.: "Indications for conservative surgery in certain renal tumors: a study based on the growth patterns of clear cell carcinoma." J. Urol., 64: 200, PETRITSCH, P.H.; RAUCHENWALD, M.; ZECHNER, O. et al.: "Results after organ-preserving surgery for renal cell carcinoma. An Austrian multicenter study." Eur. Urol., 18: 84, NOVICK, A.C.; GEPHARDT, G.; GUZ, B. et al.: "Long term follow-up after partial nephrectomy of a solitary kidney." N. Engl. J. Med., 325: 1058, *43. Herr, H.W.: "Partial nephrectomy for unilateral renal carcinoma and a normal contralateral kidney:10-year follow-up." J. Urol., 161: 33, WINFIELD, H.N.; DONOVAN, J.F.; LUND, G.O. et al.: "Laparoscopic partial nephrectomy: initial experience and comparison to the open surgical approach." J. Urol., 153: 1409, FERGANY, A.F.; HAFEZ, K.S. and NOVICK, A.C.: "Long-term results of nephron sparing surgery for localized renal cell carcinoma: 10-year follow-up." J. Urol., 163: 442, BOSTWICK, D.G. and MURPHY, G.P.: "Diagnosis and prognosis of renal cell carcinoma: Highlights from an international consensus workshop." Semin. Urol. Oncol., 16: 46, GILL, I.S.; MATIN, S.; DESAI, M.M. et al.: "Laparoscopic versus open partial nephrectomy in 200 cases. Submitted. 48. STEPHENSON, R.A.; KING, D. and ROHR, R.L.: "Re-

13 880 nal cryoablation in the canine model." Urology, 47: 772, GILL, I.S.; MATAMOROS, A.; HEFFRON, T.G. et al.: "Laparoscopic renal cryoablation." J. Urol., 157: 210, COZZI, P.J.; LYNCH, W.J.; COLLINS, S. et al.: "Renal cryotherapy in the sheep model; a feasibility study." J. Urol., 157: 710, UCHIDA, M.; IMAIDE, Y.; SUGIMOTO, K. et al.: "Percutaneous cryosurgery for renal tumors." Br. J. Urol., 745: 132, BAUST, J.; GAGE, A.A.; MA, H. et al.: "Minimally invasive cryosurgery-technological advances." Cryobiology, 34: 373, *53. GILL, I.S.; NOVICK, A.C.; SOBLE, J.J. et al.: "Laparoscopic renal cryoablation: initial clinical series." Urology, 52: 543, CHAN, D.; KONIARIS, L.; MAGEE, C. et al.: "Feasibility of ablating normal renal parenchyma by intracavitary photon radiation energy in a canine model." J. Endourol., 13: A13, PATEL, V.R.; LEVEILLE, R.J.; HERRON, A. et al.: " Wet radiofrequency ablation of the rabbit kidney using the liquid electrode: Acute and chronic observations." J. Endourol., 13: A14, HUIDOBRO, C.; LARSON, T.; PLATZ, C. et al.: "Ablation of the prostate using thermal rods." J. Endourol., 13: A97, KORMAN, K.U.; MICHEL, M.S.; RASSWEILER, J.J. et al.: "Shock waves-focused ultrasound." In Smith, A.D., Badlani, G., Bagley, D., et al:smith's textbook of Endourology. St. Louis, Quality Medical, 1996, pp