Vasovasostomy in dogs using the carbon dioxide milliwatt laser: Part II

Unilateral and bilateral vasectomy in the dog: alkaline phosphatase as an indicator of tubular patency

The objective of this research was to use a model of unilateral and bilateral occlusion of the ductus deferens in the dog to study the use of alkaline phosphatase (AP) as an indicator of tubular patency. Seven healthy cross bred dogs weighing 10-15 kg BW with normal spermiogram and AP concentrations in semen were used. From each dog, three semen samples were obtained before (intact) and after right (unilateral) and left (bilateral) vasectomy. The AP concentrations were measured in duplicates by a colorimetric method in each of the three fractions (first, second (sperm-rich), third) of each ejaculate. In addition, a macroscopic and microscopic evaluation of each ejaculate was carried out to assure its quality. Data were analysed by least squares analysis of variance using SAS(R). In intact and unilateral vasectomized dogs, 96.6% of AP measured in semen corresponded to the second sperm-rich fraction whereas 1.53 and 1.83% corresponded to the first and third fractions respectively. Total AP concentrations (first and second and third fraction) in vasectomized dogs were lower than in intact animals (19.857 vs 2284.431 +/- 4.347 UAL; p < 0.001). AP concentrations were much lower in bilateral than in unilateral vasectomized dogs (142 vs 39.572 +/- 4.347 UL, p < 0.001). In summary, AP concentrations in semen can be used as an early indicator of unilateral or bilateral lack of patency of the epididymal and deferent ducts in the dog.

Laser tissue welding: a urological surgeon's perspective

Laser tissue welding has proven its efficacy in the laboratory setting when compared with more traditional modalities of tissue reapproximation. In the clinical environment, several areas including urethral reconstructive surgery have shown great promise. Several technological advancements including solder development, chromophore enhancement and temperature control have improved upon the welding process and have added more precision and reproducibility to the technique. The current potential applications for laser welding in urology are numerous. On a molecular level, growth factor supplementation has certain potential in improving upon weld site healing and wound strength. Laparoscopic surgery with its need for less cumbersome modes of tissue closure is a field that will greatly benefit from the technology of laser tissue welding. Surgical specialties outside of urology are also participating in developing the field of laser welding. In particular, cardiothoracic surgery, otolaryngology, plastic surgery, neurosurgery among others, have utilized the concept of laser tissue welding. There are many ares that have potential use for laser welding that have yet to be explored. Further investigation will likely reveal more applications for this valuable technology.

Laser tissue welding

Laser tissue welding is a technologic innovation that is beginning to move from the theoretical laboratory environment to the reality of clinical application. This article reviews the concepts, potential advantages, and techniques involved in laser tissue welding as they apply to urology.

Silver halide fiber optic radiometric temperature measurement and control of CO2 laser-irradiated tissues and application to tissue welding

Tissue heating by laser irradiation has attained importance in many clinical applications. Accurate temperature measurements of laser-irradiated tissues are difficult to achieve, and experiments have produced conflicting results. Fiber optic radiometry allows temperature measurement of laser-irradiated tissues by remote sensing of the emitted infra red (IR) radiation. We have developed an IR fiber optic radiometer capable of accurate tissue temperature measurements (+/- 0.2 degrees C) and utilized it to monitor and control the heating of tissues by CO2 laser irradiation. Tissue temperature control of +/- 2.5 degrees C was achieved. This system was used to control tissue temperature during CO2 laser-assisted welding of urinary bladders in rats. The strength of the welds was recorded for different welding temperatures. A temperature of 55 degrees C was found to be optimal.

Vasal anastomoses in dogs using contact neodymium:yttrium aluminum garnet (Nd:YAG) laser

The purpose of this study is to evaluate the contact Nd:YAG laser system for vasal anastomosis in the animal model. Eighteen mongrel dogs were used. In this study, two major groups--control and laser--were defined. In the control group, vas anastomoses were performed with conventional microsurgical technique in six dogs. In the laser group, we performed contact laser assisted vas anastomosis (CLAVA) in 12 dogs by means of a contact Nd:YAG laser with synthetic sapphire probe (ERP4), emitted 2.0 sec pulse duration of minimum 1 watt to maximum 10 watts power. The time needed for completion of the vasal anastomosis in CLAVA group was 2-3 min; in the control group, approximately 25 min. The patency rate did not differ in these two groups; however, microscopic sperm granuloma formation was 16.7% (2/12) in the control group but 0% (0/12) in the CLAVA group. In conclusion, CLAVA is a fast and simple technique for vasal anastomosis and there were no significant complications, sperm granuloma, or even significant swelling or hematoma in any animal in this experiment.