RECONSTRUCTIVE UROLOGY

Laser welded vesicourethral anastomosis in an in vivo canine model: a pilot study
Grummet JP, Costello AJ, Swanson DA, Stephens LC, Cromeens DM
Division of Urology, Department of Surgery, University of Melbourne, Melbourne, Australia
J Urol. 2002; 168:281-4

• Purpose: We evaluated laser welding as an alternative method of forming the vesicourethral anastomosis.
• Materials and Methods: Eight dogs underwent open total prostatectomy, including 4 in which the vesicourethral anastomosis was formed by 830 nm. diode laser welding using a chromophore doped albumin solder and 3 or 4 support sutures. The remaining 4 anastomoses were conventionally formed using 8 interrupted sutures. Acute leakage was tested intraoperatively. The anastomosis of 1 animal per group was assessed on postoperative days 3, 5, 7 and 14 by radiography before sacrifice. Each anastomotic specimen was then tested for leak pressure and examined histologically.
• Results: There were no leaks during intraoperative testing of laser welded or sutured anastomoses. On radiography there were no leaks in the laser welded group. In 1 control there was slight localized leakage. All anastomoses achieved physiological leak pressures of 70 mm. Hg or greater with 3 of the 4 in the laser welded group recording supraphysiological pressures of greater than 200 mm. Hg. While 3 of the 4 laser welded specimens showed evidence of muscle necrosis, there were no other differences in healing in the 2 groups.
• Conclusions: These short-term results suggest that diode laser welded vesicourethral anastomosis is feasible. This technique has the potential to simplify anastomotic formation in laparoscopic radical prostatectomy, shortening operative time. Diode laser welding in this small cohort created an immediate and ongoing watertight anastomosis and, therefore, it may also be an alternative in open radical prostatectomy cases. Further study is needed to assess long-term effects on healing.
  
  
• Editorial Comment
  Laparoscopy has had more and more influence on urological surgery in recent years. While retroperitoneal surgical procedures are now routinely performed in many centers, laparoscopic surgery for urologic tumors in the pelvis has not gained such a wide acceptance yet. This is particularly true for laparoscopic cystectomy, mostly due to the fact that a subsequent urinary diversion needs a lot of time consuming suturing.
  In this paper the authors have again taken up laser welding as a possible technique to create a surgical anastomosis, thereby reducing the amount of necessary sutures. They chose vesicourethral anastomosis after radical prostatectomy in a canine model. Laser welding was performed with a diode laser, a liquid solder containing lyophilized bovine serum albumin mixed with indocyanine green dye as a chromophore. With this technique they were able to create a vesicourethral anastomosis which was watertight at intraluminal pressures exceeding 200 mmHg after 7 days.
  If laser welding can be applied for pelvic laparoscopic surgery, it will not only further increase the number of laparoscopic radical prostatectomies, due to the reduction of operating time and necessary training of newcomers in the field of laparoscopy, but it may also make laparoscopic cystectomy and urinary diversion an option for many more centers then just the few which perform this type of surgery still rather infrequently. However, several questions must still be solved. We don’t know how a solder consisting of bovine serum albumine or any other non-autologous preparation will react in the human setting. May this create a larger number of strictures? Or may it even create immunologic reactions in some patients? Another problem is still the unpredictable tissue damage created by the laser-induced welding process, as well as individual differences in the absorption characteristics and visual estimation of a completed welding.
  Nevertheless, welding seems to be a viable option for approximating human tissues. It should be possible to solve the remaining questions in the upcoming years, and thus make laser welding a possible technique for laparoscopy, which might give minimal invasive surgery a new boost.

Dr. Arnulf Stenzl
Professor and Chairman of Urology
Eberhard-Karls-University Tuebingen
Tuebingen, Germany