HYDRO-JET ASSISTED LAPAROSCOPIC PARTIAL NEPHRECTOMY:: INITIAL EXPERIENCE IN A PORCINE MODEL

Laparoscopic partial nephrectomy

BACKGROUND AND PURPOSE

The technique of laparoscopic partial nephrectomy has matured significantly over the past decade and is emerging as an oncologically sound procedure for the management of small renal tumors. Methods of tumor excision as well as parenchymal reconstruction in a hemostatically controlled field have evolved to make this procedure safer. Improved techniques to minimize warm renal ischemia are being developed. Finally, methods to prevent positive surgical margins during laparoscopic surgery are crucial to a satisfactory oncologic outcome. These important technical issues, as well as the current results of laparoscopic partial nephrectomy, are discussed.

MATERIALS AND METHODS

The urologic peer-review literature related to nephron-sparing surgery was reviewed. Controversial issues with respect to the surgical approach, methods of hemostatic control, acceptable time of warm ischemia, and cooling techniques were reviewed and collated. Perioperative results from larger series of laparoscopic and open partial nephrectomy were evaluated.

RESULTS

Open nephron-sparing surgery for renal tumors < or =4 cm has cancer control equivalent to that of open radical nephrectomy. Evidence is now emerging that laparoscopic partial nephrectomy will provide similar oncologic results, although clinical follow-up is still early. Blood loss, postoperative pain, and convalescence seem to be favor the laparoscopic approach. Complication rates, primarily postoperative bleeding and urine leak, may be higher than for open nephron-sparing surgery. Methods of laparoscopic hemostatic control favor soft vascular clamping for larger tumors that are more endophytic and central. Smaller exophytic lesions may be managed without renal vascular control using a variety of coagulative and hemostatic tools. Data related to warm renal ischemia suggest that the time used for tumor excision and renal reconstruction should be 30 minutes or less. Techniques for laparoscopic renal cooling are being developed.

CONCLUSIONS

Laparoscopic nephron-sparing surgery is a technique in evolution but with a promising outlook. The urologic peer-review literature reflects an exponential growth in interest, which suggests that this minimally invasive approach is practical and may benefit our patient population so as to allow them to return to normal healthy living more quickly.

Nerve-sparing retroperitoneal lymphadenectomy using hydro-jet dissection: initial experience

BACKGROUND AND PURPOSE

Nerve-sparing retroperitoneal lymphadenectomy (RPL) is performed in a significant number of patients to preserve ejaculation after treatment for testicular cancer. Identification and preservation of the sympathetic nerves may be challenging. Hydro-Jet technology has been utilized for various surgical applications. A small high-pressure stream of water is used to delineate surgical planes, with preservation of vascular and neural structures. We have examined the utility of this technology for RPL in a porcine model and in human subjects.

MATERIALS AND METHOD

A Helix Hydro-Jet device (Erbe, USA) was used for all procedures. A high-pressure water-jet stream is directed through a small nozzle with a 120-microm inner radius for soft-tissue dissection. The upper pressure limit (range 0-2175 psi) is set using a digital monitor. The jet is initiated using a foot pedal, and the actual pressure is monitored. A pressure of 360 to 400 psi was used for experimental studies, which was decreased to 255 to 300 psi for human use. Three pigs underwent RPL using this technique. Subsequently, RPL was performed in five men with testicular cancer, being primary in two and postchemotherapy in three. The primary diagnosis was seminoma in one and non-seminomatous cancer in four. The patient with seminoma had a residual mass after chemotherapy.

RESULTS

The procedures were completed successfully in all subjects. There were no intraoperative or postoperative complications. Hydro-Jet dissection permitted tissue selectivity, with preservation of vascular structures and sympathetic nerves. The soft tissue and lymphatics were removed with the high-pressure water stream assisted by blunt dissection. The nerve fibers were grossly resistant to the pressure used and were isolated individually. Dissection around the great vessels appeared to be safe, and no injury was observed with direct application of the jet. Lumbar arteries and veins and accessory vessels could be isolated safely. The estimated blood loss was minimal in animals and 300 to 800 mL in humans.

CONCLUSIONS

Hydro-Jet dissection demonstrated tissue selectivity using a pressure range of 255 to 300 psi in humans. The vascular structures and sympathetic nerves were preserved. Our initial experience with this device for nerve-sparing RPL is encouraging.

Laparoscopic nephron-sparing surgery in a Jehovah's Witness patient

An obese 76-year-old woman with type II diabetes, hypertension, coronary artery disease, and gastroesophageal reflux was found to have a 6-cm lower-pole mass in a solitary functional right kidney. Because her religious beliefs prohibited blood transfusion, minimally invasive surgery--a laparoscopic partial nephrectomy--was performed, with a good result. Minimally invasive surgery, perhaps with administration of erythropoietin, iron-dextran, or both, is often a good option for severely anemic patients or those whose religious beliefs are opposed to transfusion. Methods of minimizing blood loss intraoperatively are reviewed.

Sutureless laparoscopic heminephrectomy using laser tissue soldering

BACKGROUND AND PURPOSE

Widespread application of laparoscopic partial nephrectomy has been limited by the lack of a reliable means of attaining hemostasis. We describe laser tissue welding using human albumin as a solder to control bleeding and seal the collecting system during laparoscopic heminephrectomy in a porcine model.

MATERIALS AND METHODS

Laparoscopic left lower-pole heminephrectomy was performed in five female domestic pigs after occluding the hilar vessels. Using an 810-nm pulsed diode laser (20 W), a 50% liquid albumin-indocyanine green solder was welded to the cut edge of the renal parenchyma to seal the collecting system and achieve hemostasis. Two weeks later, an identical procedure was performed on the right kidney, after which, the animals were sacrificed and both kidneys were harvested for ex vivo retrograde pyelograms and histopathologic analysis.

RESULTS

All 10 heminephrectomies were performed without complication. The mean operative time was 82 minutes, with an average blood loss of 43.5 mL per procedure. The mean warm ischemia time was 11.7 minutes. For each heminephrectomy, a mean of 4.2 mL of solder was welded to the cut parenchymal surface. In three of the five acute kidneys and all five 2-week kidneys, ex vivo retrograde pyelograms demonstrated no extravasation. In addition, no animal had clinical evidence of urinoma or delayed hemorrhage. Histopathologic analysis showed preservation of the renal parenchyma immediately beneath the solder.

DISCUSSION

Laser tissue welding provided reliable hemostasis and closure of the collecting system while protecting the underlying parenchyma from the deleterious effect of the laser during porcine laparoscopic heminephrectomy.

Laparoscopic partial nephrectomy with a diode laser: porcine results

PURPOSE

To develop a safe and effective technique for laparoscopic partial nephrectomy without need for hilar occlusion.

MATERIALS AND METHODS

Laparoscopic transperitoneal lower-pole partial nephrectomy was performed in five 45- to 50-kg female farm pigs using a 980-nm diode laser. Standard transperitoneal access was obtained, and a four-port approach was used to perform a laparoscopic right partial nephrectomy using a diode laser (23 W) without hilar occlusion. The pigs were allowed to recover and 2 weeks later underwent a left laparoscopic partial nephrectomy. Postoperatively, renal function was monitored by serial serum creatinine measurements. Both kidneys and ureters were removed for ex-vivo retrograde pyelograms and histologic analysis.

RESULTS

The 980-nm diode laser resulted in successful lower-pole partial nephrectomy without hilar occlusion in all 10 of the kidneys. In three cases, laser hemostasis was insufficient, and adjunctive hemostatic clips were necessary to stop bleeding. The mean operative time was 126 minutes, and the mean laser time was 84 minutes. An average of 23% (range 13%-33%) of the kidney parenchyma was resected. The mean blood loss was 150 mL (range 50-300 mL). There was no evidence of urinary extravasation on ex-vivo retrograde pyelograms at 2 weeks in any of the kidneys.

CONCLUSION

Laparoscopic partial nephrectomy without hilar occlusion using the 980-nm diode laser is feasible in the porcine model. Because adjunctive hemostatic measures may be necessary in some cases, clinical trials in humans should be limited to small exophytic tumors.

Minimally invasive management of the small renal tumor: review of laparoscopic partial nephrectomy and ablative techniques

The most profound change among the many that have occurred in the management of renal-cell carcinoma (RCC) in recent years is the advent of nephron-sparing surgery for masses <4 cm. The main challenge now is to reduce the morbidity associated with such procedures. Because of the problems in obtaining hemostasis, only a few highly experienced surgeons are performing partial nephrectomy laparoscopically. Numerous techniques and tools have been studied, including laparoscopic duplication of the open operation; hand-assisted surgery; double-loop and cable-tie tourniquets; ultrasonic shears; radiofrequency, microwave, and laser energy; the Endosnare; and hydro-jet dissection. Also, ablation with cold, radiofrequency energy, or high-intensity focused ultrasound is being explored. Just as open surgery for urolithiasis has been all but replaced by extracorporeal lithotripsy and endoscopic techniques, treatment of most RCCs will ultimately shift from open to minimally invasive methods.

Hydro-jet-assisted pneumonectomy: a new technique in a porcine model

BACKGROUND AND OBJECTIVES

Hydro-jet technology has long been used to cut various materials, such as metal and wood, in the industrial field. In the medical field, this technology has been applied successfully in selective cutting of the parenchyma of the liver. However, to our knowledge, no data are available on the use of the hydro-jet technique for pneumonectomy. The purpose of this study was to evaluate a new dissection technique in which a high-pressure water stream (hydro-jet) and a new dissection probe for pulmonary resection are used.

METHODS

Thirty pigs underwent right pneumonectomy. Pigs were randomized to either the conventional or hydro-jet-assisted dissection technique. The feasibility of this technique and the features of surgical dissection were evaluated and compared between the two groups.

RESULTS

Pneumonectomy was successful in all animals. The mean operative times were 55 and 65 minutes and the mean volumes of blood loss were 37 and 65 mL for the hydro-jet and conventional dissection techniques, respectively. Complications included vascular injury in 6% and 20% of cases with the hydro-jet and conventional techniques, respectively. The use of hydro-jet for pneumonectomy had clear technical advantages over the conventional dissection. Hydro-jet resulted in a selective dissection of fibrous and connective tissue, preserving blood vessels for later ligation. Therefore, the dissection was performed in a relatively bloodless field. The ease of dissection with the bent-tip dissector represents another advantage. The continuous water flow allows a clear view for the operator.

CONCLUSIONS

This study shows that hydro-jet dissection represents an excellent alternative to the conventional technique for pulmonary resection. The improved anatomic dissection combined with an almost bloodless operating field secondary to continuous water flow may decrease dissection-related complications.

Local hemostasis during laparoscopic partial nephrectomy using biodegradable hydrogels: initial porcine results

BACKGROUND AND PURPOSE

Despite the advance of laparoscopic partial nephrectomy, significant technical limitations remain with regard to control of bleeding and closure of the collecting system. An attractive approach on the horizon for local hemostatic and wound control is the use of local tissue sealants. To date, sealants remain largely derived from natural biologic products and are difficult to apply laparoscopically with precise local control. In this study, we examined the novel strategy of forming occlusive tissue-adherent hydrogels utilizing a synthetic biodegradable polyethylene glycol-lactide copolymer (PEG-lactide) as an in situ occlusive barrier for hemostasis and wound control. Specifically, the objects of this study were to determine if PEG-lactide hydrogels could be formed intraperitoneally on renal tissue, to test the adhesiveness of the hydrogels to injured renal parenchyma, and to evaluate the ability of adherent hydrogel barriers to limit renal parenchymal bleeding and collecting system leakage following renal pole amputation or wedge excision.

MATERIALS AND METHODS

Five kidneys from three female pigs were used in a nonsurvival study. A standardized model for laparoscopic partial nephrectomy was created by performing wedge excision or polar amputation under vascular control using a laparoscopic Satinsky clamp. Bleeding briskness following injury was assessed utilizing a scoring system and free blood quantitated comparing a conventional "clamp and wait" strategy with an adherent hydrogel strategy. For the hydrogel group, PEG-lactide hydrogel primer and macromer were applied through laparoscopic ports. The hydrogel was polymerized using a xenon light source, and the pedicle clamp was released to observe for bleeding. A subsequent opposite polar injury was created to confirm renal perfusion and the sites were compared. The kidneys were removed, and the adhesion of the hydrogel to the renal parenchyma was examined.

RESULTS

The PEG-lactide macromer was effectively applied to five kidneys following partial nephrectomy. In all cases, successful intraperitoneal in situ polymerization was achieved, with resultant hydrogel formation. Polymeric hydrogel adhesion to the cut renal parenchyma was assessed semiquantitatively following vigorous cyclic washing. In all cases, polymer gels remained adherent without any evidence of peeling, delamination, or separation from the underlying tissue surface. In the control group, the mean bleeding score was 2.63 +/- 0.48 v 0.00 +/- 0.00 in the gel-treated group (P < 0.001). Blood loss in the control group was 56 +/- 5 ml v 0.00 +/- 0.00 in the gel-treated group (P < 0.001). In an ex vivo retrograde ureteral perfusion, no leakage was observed at pressure as high as 100 mm Hg.

CONCLUSIONS

In this feasibility study, a biodegradable PEG-lactide polymer system photopolymerized rapidly in situ on exposed renal parenchymal surfaces, forming adherent hydrogel barriers. When applied during vascular clamping, an adequate physical bond and patch-like cap was created to prevent bleeding at physiologic renal perfusion pressures. Use of locally applied occlusive hydrogels holds promise for hemostasis and local wound control during laparoscopic urologic procedures.