Laser-Assisted Vas Anastomosis: A Preliminary Report

Lasers in Surgery and Medicine 3: 261-263 (1983)

Laser-Assisted Vas Anastomosis: A Preliminary Report Charles M. Lynne, MD, Melvin Carter, James Morris, Douglas Dew, Sharon Thomsen, MD, and Cathy Thomsen, MD Departments of Urology (C.M.L.), Orthopaedics Rehabilitation (M.C., J. M., D.D., C.T), and Pathology (S. T.), University of Miami School of Medicine, Miami

A new technique is described for performing vas anastomoses in experimental animal (rats). A low-power COz laser appears to be effective in welding together the cut ends of the divided vas deferens. Key words: lasers, urology, microsurgery, infertility, vasovasostomy

INTRODUCTION

The surgical objectives of a successful vasovasostomy should be approximation of the vas lumina and a sperm-tight anastomosis. The authors, for the past 2 years, have been developing techniques for the use of laser energy to “weld” severed tissues together by thermal coagulation. To date, small blood vessels (rat femoral arteries and veins), peripheral nerves, cartilage, and skin, as well as vas deferens, have been successfully welded. We herein report our initial efforts with laser-assisted vas anastomosis (LAVA), MATERIALS AND METHODS

A specially constructed optical bench, continuous-wave, R.F. -excited, CO, laser delivering approximately 100-200 mW of energy with a beam spot size of approximately 0.2-0.5 mm was used to weld by thermal coagulation the edges of tissue held in approximation. The following technique was evolved using adult male rats: The vas deferens is dissected out in the inguinal region. The vas is divided, and the large vessels accompanying it are cauterized with bipolar cauterizing jeweler forceps. With optical magnification (in this case a standard operating microscope), sutures of 10-0 nylon are placed full thickness from serosa through muscularis and lumen of one vas segment then outward full thickness through lumen then muscularis and serosa of the Address reprint requests to Charles M. Lynne, MD, Department of Urology, D-1, University of Miami School of Medicine, P.O. Box 016217, Miami, FL 33101.

0 1983 Alan R. Liss, Inc.

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Lynneetal

Fig. 1. Photomicrograph ( x 10) of healed laser welded vasovasostomy in rat vas deferens. (Epithelial surface at top.)

other segment. Generally, three sutures 120" apart will be necessary for good approximation of the entire circumference of the wound edges. The sutures are tied, and the ends are left long enough to allow easy grasping with forceps. The ends of two adjacent sutures are then grasped and pulled outward to stabilize the wound edges, and the opposed cut edges of the vas are coagulated to form the anastomic bond. This is accomplished by moving the two opposed edges of tissue back and forth under the laser beam. The strongest bond is formed when the wound tissues become slightly dry and contracted as the laser coagulation occurs. If the laser beam is applied to the tissue much longer after the visual changes are seen, charring of the tissue will occur. Each segment of the circumference in turn is then coagulated. With little practice, the entire anastomosis can be accomplished in 5 min or less; the laser welding itself taking only 30 to 45 sec in toto. RESULTS

As this initial study was undertaken only to develop technique and determine efficacy, only fully healed anastomoses were examined pathologically. The healed wound is thinner than the vas deferens muscular wall, and is formed by fibrous connective tissue intermingling with the smooth muscle fibers (Fig. 1). No sperm granulomas and very little inflammatory response are seen in the scar tissue. The luminal surface of the wound is covered by cuboidal epithelial cells and cicatricial collagen. DISCUSSION

It became apparent as the technique was evolved that because of the thick muscular wall and mobility of the vas deferens that the use of stay sutures would be necessary for two reasons: first, to achieve good approximation of the cut ends being welded; and second, to obtain a tensile strength of the coagulated tissues sufficient to hold the anastomosis. We anticipate even more stress on the anastomosis when performed in the human scrota1 vas.

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Comparison of healed laser-welded vasovasostomies with those done by suture only initially showed few differences. Healing was complete. In the laser specimens, the only areas showing inflammatory changes were around the nylon sutures. The welded specimens appeared to have a circumferential area of thinning of the muscularis at the anastomosis more prominent than in the sutured specimens. The rate and nature of the healing process in this tissue are being further investigated. The advantage of being able to achieve a sperm-tight anastomosis while using only a few sutures is apparent. To be able to do this in less time than with standard techniques is an added bonus. CONCLUSIONS

We feel that the vas deferens can be successfully reanastomosed using a minimum of sutures for approximation and low-power laser coagulation to achieve a sperm-tight seal. Our initial impression is that healing occurs at least as rapidly as with standard techniques with very minimal scar formation. Further studies are underway to determine more precisely the rate and nature of the healing process of this unique new procedure. ACKNOWLEDGMENTS

This work was supported in part by BSRG RR05363 and the generous contribution of the United Technologies Corporation.