Partial nephrectomy using the Nd:YAG laser: a comparison of the 1.06 mu and 1.32 mu lasers employing different delivery systems

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.

Water-jet dissection in renal surgery: experimental study of a new device in the pig

The pig model was used for experiments with a new type of water-jet dissector, which produces high-pressure water by application of a gas and maintains the water fully sterile in a single-use delivery apparatus. The experiment was conducted ex vivo (14 kidneys) and in vivo to compare electric cautery section with water-jet dissection (5 vs 11 partial nephrectomies). Ex vivo study confirmed sparing of blood vessels and pelvicaliceal system. In vivo study did not show significant differences in blood loss but, the water-jet allowed precise dissection and tight closure of the excretory system. More frequent haemorrhages were noted on histological examination of the WJ group, but no coagulation necrosis. These are preliminary findings and further studies of long-term results may confirm the benefits of the absence of parenchymal necrosis and the definite advantage of precise closure of the pelvicaliceal system, as morbidity of partial nephrectomy is often related to secondary haemorrhages and urinary fistulae.

Lasers in urology

Ever since Mulvany first described use of Ruby laser for lithotripsy, urologists have been exploiting every possible application of this technology. Laser lithotripsy in the 1980s and now laser prostatectomy in the 1990s have dominated laser usage in urology. Applications of lasers for superficial lesions (e.g., condylomata acuminata and carcinoma of penis) have found an established role. Interests in laser welding, photodynamic therapy and fluorescence continues to grow and evolve. The laser industry at the same time is striving to provide more efficient lasers. High power lasers (Holmium:YAG, KTP:YAG) and laser machines combining double wavelengths (Nd:YAG and KTP, Ho: YAG and Nd:YAG) are commercially available. Diode lasers with their portability and reliability qualities can now provide high output powers in various wavelengths. Here, we have reviewed different lasers, laser tissue interaction and clinical laser applications relevent to urology.

Partial nephrectomy with a combined CO2 and Nd:YAG laser: experimental study in pigs

Twenty-eight partial nephrectomies were performed on nine pigs with a simultaneous, coaxial CO2-Nd:YAG laser at power settings of 20 W and 40 W, or with a steel scalpel. A vascular pedicle clamp was used without renal cooling. The time for hemostasis was 4.5 +/- 3.2 min (mean +/- SD) with the laser and 6.4 +/- 2.5 min with the steel scalpel (P = 0.064). There was no difference in the total operation time (10.4 +/- 3.5 min with the laser vs. 11.0 +/- 3.2 min with the steel scalpel, P = 0.470). The mean blood loss with the laser was 17.5 +/- 6.7 g and 22.1 +/- 15.2 g with the steel scalpel (P = 0.299). The number of ligatures needed for complete hemostasis was 2.9 +/- 2.1 with the laser and 5.0 +/- 2.3 with the steel scalpel (P = 0.011). The average thermal damage was 0.23 +/- 0.10 mm. It is concluded that the simultaneous CO2-Nd:YAG laser method can be used in partial nephrectomy and it offers better hemostasis than the conventional technique. Further studies with different power levels are needed.

Contact fibre Nd:YAG laser for partial nephrectomy: experimental study in pigs

Thirty-two partial nephrectomies were performed without renal cooling on 13 pigs with a contact fibre Nd:YAG laser (10 W) or a steel scalpel with or without a vascular pedicle clamp. Nine pigs had a 2-week follow-up with an abdominal ultrasound 1 week postoperatively. The time for haemostasis was 6.9 +/- 5.2 min (mean +/- SD) with the laser and 9.1 +/- 5.8 min with the steel scalpel when the clamp was used (P = 0.028). There was no significant difference in the total operating time (13.2 +/- 4.5 min with the laser vs 12.6 +/- 4.6 min with the steel scalpel, P = 0.203). Intraoperative blood loss was similar in the two groups when the clamp was used. Clamping the renal pedicle decreased the blood loss by 61% in the laser group and 31% in the steel scalpel group. The number of ligatures used was significantly lower in the laser group (3.7 +/- 2.6) compared with the steel scalpel group (6.6 +/- 3.4) (P = 0.013). Five urinomas developed on the laser side and four on the steel scalpel side. These results indicate that the contact fibre Nd:YAG laser method can be used in partial nephrectomy, but it offers no definitive advantage over the conventional technique.

Use of the holmium:YAG laser in urology

The tissue effects of a holmium:YAG (Ho:YAG) laser operating at a wavelength of 2.1 mu with a maximum power of 15 watts (W) and 10 different energy-pulse settings was systematically evaluated on kidney, bladder, prostate, ureteral, and vasal tissue in the dog. In addition, various urologic surgical procedures (partial nephrectomy, transurethral laser incision of the prostate, and laser-assisted vasovasostomy) were performed in the dog, and a laparoscopic pelvic lymph node dissection was carried out in a pig. Although the Ho:YAG laser has a strong affinity for water, precise tissue ablation was achieved in both the contact and non-contact mode when used endoscopically in a fluid medium to ablate prostatic and vesical tissue. Using the usual parameters for tissue destruction (blanching without charring), the depth of thermal injury in the bladder and ureter was kept superficial. In performing partial nephrectomies, a 2-fold reduction in the zone of coagulative necrosis was demonstrated compared to the use of the continuous wave Neodymium:YAG laser (Nd:YAG). When used through the laparoscope, the Ho:YAG laser provided precise cutting and, combined with electrocautery, allowed the dissection to proceed quickly and smoothly. Hemostatic control was adequate in all surgical procedures. Although the results of these investigations are preliminary, our initial experience with the Ho:YAG laser has been favorable and warrants further investigations.

Renal function after partial nephrectomy with the Nd-YAG laser. Experimental study in piglets

Twelve partial nephrectomies were performed in 12 piglets using either the combination (contact and non-contact) Nd:YAG laser technique or a steel scalpel. Additional haemostasis was attempted with ligatures. The renal artery was not clamped and renal cooling was not attempted. Total nephrectomy was performed on the contralateral side. Serum creatinine and urea levels were measured, and 99mTc-DTPA renography was performed pre-operatively and 1 and 2 weeks post-operatively. One week post-operatively the mean serum creatinine level was 35% higher than the pre-operative level in the laser group and 30% higher in the steel scalpel group. Two weeks post-operatively the respective differences were 34 and 24%. The mean urea level 1 week after operation was 50% higher than the pre-operative level in the laser group and 17% higher in the steel scalpel group. Two weeks post-operatively the respective differences were 38% in the laser group and 20% in the steel scalpel group. The mean DTPA disappearance rate was 34% lower 1 week after operation in the laser group and 23% lower in the steel scalpel group when compared with the preoperative state. Two weeks post-operatively the respective changes were 48 and 25%. These data indicate that there is no significant difference in renal function when the Nd: YAG combination laser technique is used in partial nephrectomy as compared with the steel scapel.

Efficacy and complications of the Nd:YAG laser in partial nephrectomy: experimental study in piglets

Twenty-four partial nephrectomies were performed in 18 piglets using either the combination Nd:YAG laser technique (contact and noncontact) or a steel scalpel. Additional haemostasis was attempted with ligatures. Blood loss, operation time, and number of ligatures were compared in the two treatment groups. Twelve piglets had a two-week follow-up. The mean blood loss with the laser was 72 +/- 10 g and 83 +/- 13 g with the steel scalpel (no significant difference). The resection time until complete haemostasis was 9.8 +/- 0.9 min with the laser and 14.3 +/- 1.3 min with the steel scalpel (p = 0.0076). The number of ligatures needed for complete haemostasis was 2.8 +/- 0.4 with the laser and 7.5 +/- 1.0 with the steel scalpel (p = 0.0051). Three piglets in the steel scalpel group developed urinomas. There were two perirenal abscesses, one in each group. In the steel scalpel group there was one intussusception. In conclusion, it seems that the combination Nd:YAG laser method offers no definitive advantage over the standard technique for partial nephrectomies in the pig.