Evaluation of the Stapled Anastomosis in Experimental Salpingoplasty

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Evaluation of the Stapled Anastomosis Ln Experimental Salpingoplasty GILLES D. HURTEAU, M.D.C.M., F.R.C.S.(C), F.A.C.O.G.,* and G. BRADLEY, M.D.t

for the correction of the tubal factors of infertility has been performed for a number of years. Although clinicians and research workers have devised many new technics intended to re-establish the patency of the fallopian tubes,1. 3 restoration of tubal patency and integrity remains a most perplexing problem. In recent years, the use of antibiotics and adrenocortical hormones, with tubal lavage, have relatively improved the results. 5 , 6 Polyethylene tubing with tuboplasty hoods, devised for splinting according to the method of Rock and Mulligan,12 have been used extensively for salpingoplasty. However, the polyethylene splints have, at times, been the source of mechanical irritation and may have contributed to subsequent stenosis at the anastomotic site. When projected and anchored through the cervix, they have also been the source of an ascending infection with all its implications; in fact, alternative technics for the use of the splinting catheter had to be devised. 7 Although the re-establishment of the physical permeability of the fallopian tube is already a first step toward success, more delicate atraumatic technics must be developed in order to attain the primary objective of physiologic permeability; such methods should result in improved patency and pregnancy rates. The treatment of tubal occlusion remains one of the significant problems of human sterility.2, 8 The percentage of success in tubal plastic operations, in terms of subsequent full-term pregnancies is around 10-20%.4 However,

RECONSTRUCTIVE SURGERY

From the Department of Obstetrics and Gynaecology, and the Laboratory for Experimental Surgery, University of Ottawa Medical School, Ottawa, Canada. Presented at the 12th Annual Meeting of the Canadian Society for the Study of Fertility, Halifax, Nova Scotia, Canada, June 9-10, 1965. We should like to acknowledge the invaluable technical assistance of Mr. William Watson during the course of this experiment. *Supported by the Dean's Fund of the Medical Research Council. tSupported by the Undergraduate Medical Research Scholarship Fund of the Medical Research Council.

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plastic surgery of the fallopian tube is still in the developmental stage. Improved technics should increase the possibilities for pregnancy following salpingoplasty. The Mark IV Vogelfanger N.R.C. mechanical suturing instrument, developed by the Instrument Section of the Department of Mechanical Engineering of the National Research Council, has already demonstrated high patency rates in the reanastomosis of blood vessels and ureters. 9 - 11 The purpose of the present experiment was to evaluate the effectiveness of this instrument in end-to-end salpingoplasty. RATIONALE AND EXPERIMENTAL METHOD

The experiment was carried out in New Zealand white female rabbits and unselected mongrel female dogs. The rabbit uterine horn was particularly adaptable since in view of its mobility, length, caliber, and peristalsis it closely resembles the structure and function of the fallopian tube. The ease of breeding and the short period of gestation also facilitated the evaluation of results. The thicker and less flexible dog uterine horns were used since they are more representative of the loss of mobility and thickness to be anticipated in a damaged fallopian tube following inflammation or trauma. Rabbits weighing 3-4 kg. were housed in a constant 70° -temperature environment, with a cycle of 12-h1'. periods of light and dark. The rabbit doe was isolated for at least 4 weeks before operation and subsequently for 1 month before attempts at mating were made, thereby reducing the incidence of pseudopregnancy. The dogs were also isolated to minimize the chances of pregnancy. Anesthesia was achieved with intravenous sodium pentobarbital in concentrations of 20 mg.jkg. for rabbits and 35 mg.jkg. for dogs. In spite of a careful titration technic for anesthesia, many rabbits died of respiratory failure. This problem was finally solved by using intratracheal intubation and artificial respiration until the respiratory center had recovered. All laparotomies were performed through low midline abdominal incisions and conducted under aseptic operating-room conditions. The uterine horns in the first group of rabbits were divided and then anastomosed with the N.R.C. stapler; bushings varying between 2.0 and 5.0 mm. in diameter were selected on the basis of the estimated caliber of the horn to be reconstituted (Fig. 1-4). Following isolation, the does were taken to the buck's cage for breeding. Attempts at breeding were repeated at monthly intervals for 3-4 months. Mating was observed when possible, and the presence of spermatozoa in

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2

3

4 Fig. 1. Divided rabbit horn showing eversion of proximal end. Fig. 2. Both ends of horn are everted prior to stapler anastomosis. Fig. 3. Stapler driving mechanism during anastomosis. Fig. 4. Rabbit horn, showing immediate results of anastomosis.

the vagina confirmed successful breeding. When breeding had been can .. firmed, the rabbits were re-explored on the eighth or tenth day of gestation and the status of the anastomosed horns assessed. If breeding had been unsuccessful, the stapled anastomoses were evaluated for patency by the methods established. The dog horns were divided and reconstituted bilaterally, using the 4.5 mm. or 5.0 mm. bushings. These animals were all re-explored for evaluation 20-52 days after operation. A second group of rabbits was subjected to unilateral uterine horn ligation, the opposite side being used as a control. They were re-explored 2-4 weeks later, the ligated and damaged portion of the uterine horn was resected, and the horn was reconstituted by stapler anastomosis. Three weeks following reconstructive surgery, the animals were sacrificed and the horns assessed for permeability. The results were evaluated by hysterograms or by observing patency

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when saline was injected through the uterine horn. Polyethylene tubing was cannulated through the cervix of each horn and anchored so that the tip rested proximal to the line of anastomosis; this could not be done transvaginally but was performed under anesthesia, at the final laparotomy, when the upper vagina was incised to expose the cervices for cannulation. Two milliliters of 50% Hypaque* was then injected and observed to flow beyoNd the stapled site and X-ray films were made in selected cases for documentation. Gross studies and careful dissection confirmed patency or stenosis in all cases. Blastocyst implantation sites observed on the eighth or tenth day of gestation confirmed patency and pregnancy patterns in those rabbits where breeding had been confirmed. In a few specific instances, microscopic sections were taken through anastomotic sites in pregnant and nonpregnant horns to assess the degree of tissue reaction (Fig. 6). OBSERVATIONS AND RESULTS

The first group consisted of 27 stapled anastomoses in 15 female rabbits (Table 1). Six animals died of anesthesia or other causes. Nine animals representing 16 anastomoses were followed until the experiment was completed. Breeding was successful in 3 rabbits that had undergone bilateral stapler anastomosis. In the pregnant rabbits, 1, 3, and 6 implantations either distal or proximal to the anastomotic site were noted, whereas gross inspection and dissection proved excellent patency in the contralateral reconstituted nonpregnant horn in 2 of these animals. The implantation pattern indicated that sperm migration or blastocyst nidation had occurred through a patent structure. However, a great loss of time and effort resulted from the repeated failures at mating attempts during the summer months. It had been observed that although the rabbits were induced ovulators, their breeding habits were least favorable during this period of the year, and laboratory environmental factors may have influenced this. We feel that these difficulties compromised this phase of our experiment and probably resulted in less striking results than might have been achieved if the experiment had been planned otherwise. On the other hand, 5 other horns were proved patent, with little fibrosis, when evaluated by injection or hysterogram (Fig. 5 and 6). The total patency rate was thus 10 of 16 anastomosed horns, and pregnancy was achieved in 3 of 9 animals studied. The results of stapler anastomoses performed in 5 dogs are shown in Table l. The 1 animal with unilateral anastomosis died following a post*Winthrop Laboratories, New York, N. Y.

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A 1\ ASTO.\! 0515

TABLE 1. Results of Stapler Anastomosis of Uterine Hom in Rabbits and Dogs Rabbits Stapling alone Total

No. of animals 15 No. of anastomoses 27 Patency Injection Gross Hysterogram Pregnancy Total

Stapling aftel' ligation

D*

St

6 11

9 16

Total D

6 6

2 2

S

4 4

Summal'!!

Dogs 1'ota/ D

S

1 1

4 8

5 9

5 2 4

3 10

4

6 2 8

Rabbit .• Doy,.

Total

13 20/ 33:::

4 8/9

17 28/ 42

9 2

6

15 2

3

2 8

5 22

14

~~~~

*D, died. tS, studied. tNumerator, number of animals stud it'd ; (It'nominator, total number of animals.

operative evisceration resulting from poor abdominal closure. Subsequently, interrupted nonabsorbable suture material was used. The other 4 animals were proved to have bilateral cornual patency (Fig. 7 and 8). One animal had inadvertently become pregnant and died on the twenty-second postoperative day when an implantation ruptured through the site of anastomosis; there were well-formed implants distal and proximal to the anastomosis in both horns. Although functionally the fallopian tube would not have to undergo the risks of distention by a developing blastocyst, ectopic implantation is nevertheless a constant risk where there is a possibility of disturbed physiology even in the presence of a good anatomic result. The other 3 animals showed bilateral cornual patency, excellent in 4 horns, and with slight fibrosis in the 2 others. The third group consisted of 6 female rabbits that had undergone ligation, resection, and anastomosis of one uterine horn (Table 1). The 4 surviving animals were subjected to resection of the damaged portion of the horn with stapler anastomosis, 3-4 weeks following the initial ligation. Patency was proved by hysterogram some 25 days after surgery in all 4 reconstructed tubes; 2 of these yielded an excellent result. The 2 others were perhaps more significant since the initial ligation had produced some distention of the horn distally. Notwithstanding, resection and stapler anastomosis could be achieved easily, with little technical difficulty, in spite of the fact that the apposing ends were different in diameter and thickness. The patency achieved was excellent although moderate stenosis with minimal distal distention of the horns was noted.

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Pig. 5. Hysterogram 3 months after operation, showing patency of stapled horns in rahbit.

Pig. 6. Section of rabbit hom showing minimal fibrosis and patency at site of stapler anastomosis. (X 40)

In summary (Table 1), 42 anastomoses were performed, of which 28 could be evaluated in 17 surviving animals. Of the 28 anastomoses evaluated, 22 were patent; 15 of these were observed to be permeable by the injection of opaque material or saline; 5 horns were proved patent by the occurrence of pregnancy; and 2 were noted to be open by gross examination. All results were confirmed by gross examination and dissection. Microscopic sections through selected anastomotic sites revealed minimal tissue reaction and fibrosis.

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Fig. 7. Hysterogram 52 days after operation, showing patency of stapled horns in dog.

Fig. 8. Horn of same dog as in Fig. 7, showing minimal fibrosis.

DISCUSSION

The findings summarize the exploratory studies designed to assess experimentally the effectiveness of the Mark IV Vogelfanger N.R.C. stapler in the anastomosis of uterine horns. The initial difficulties were mostly technical. The ends were anastomosed with too much eversion of mucosa, causing a redundant reapproximation which healed with excessive granulation tissue. The latter often resulted

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in excessive fibrosis or extraluminal adhesions which accounted for most of our poor results. As the technic was gradually improved, the anastomosis was made with greater precision, less trauma, less loss of blood, and less mucosal eversion. The animals treated later in the series yielded far better results. The advantages of stapler anastomosis over the conventional technics were soon quite evident. The mounting of even diseased tissues over the instrument and its assembly for stapling is simple and non traumatic. The automatic everter produces a mucosa-to-mucosa anastomosis which is precise; the tiny metal staples may afford a built-in splinting apparatus which should render unnecessary the use of intratubal devices, with their inherent problems. Microscopic studies seem to indicate that the inert tantalum staples minimize tissue reaction such as that produced by catgut, thereby reducing postoperative stenosis. Further experimental evaluation is intended with particular reference to long-term follow-ups. Better results are to be anticipated as the refinements of the technic are developed and the use of the instrument is further mastered. A new stapler now being planned, with a diameter range of 6.0-12 mm., may increase the scope of application of this instrument in end-to-end anastomosis. An alteration of the instrument may eventually permit the eversion of the distal end of the fallopian tube, thereby facilitating the technic of fimbrioplasty. One would expect that in time, the Vogelfanger N.R.C. mechanical suturing instrument will be clinically and technically useful for end-to-end salpingoplasty and perhaps even fimbrioplasty in the human. CONCLUSION

Exploratory studies of the N.R.C. stapler provide a patency and pregnancy rate that are sufficiently promising to warrant intensive experimental evaluation which may permit its future clinical application. Department af Obstetrics and Gynaecalagy Ottawa General H aspitaZ Ottawa, Canada

REFERENCES 1. BASILE, H. N. The snorkel operation or vital tube in the treatment of tubal obstructions. CR Sac Franc Gynec 29:187, 1959. 2. BUXTON, C. L., and SOUTHAM, A. L. Human Infertility. Hoeber, New York, 1958. 3. DUBNOV, M. V., et aZ. On the technic of transplanting the fallopian tubes into the uterus. Akush Ginek 39:28, 1963.

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4. HANTON, E. M., PRATT, J. H., and BANNER, E. A. Tubal plastic surgery at the Mayo Clinic. Arner J Obstet Gynec 89:934, 1964. 5. LEROUX, M. M., et al. Traitement des facteurs tubaires de sterilite par l'hydrotubation. Bull Fed Gynec Obstet Franc 16:202, 1964. 6. MOTOYUKI, H. Surgical procedures for establishing tubal patency. Arner J Obstet Gynec 84:79, 1962. 7. NOYES, R. W. A technique for salpingoplasty. Arner J Obstet Gynec 81:812, 1961. 8. SIEGLER, M. A., and HELLMAN, L. M. Tubal plastic surgery. Arner J Obstet Gynec 86:448, 1963. 9. VOGELFANGER, 1. J., and BEATTIE, W. G. A concept of automation in vascular surgery; a preliminary report on a mechanical instrument for arterial anastomosis. Canad J Surg 1:262, 1958. 10. WADDELL, W. G., et al. Venous valve transplantation. AMA Arch Surg 88:5, 1964. 11. COLLINS, W. E., MURPHY, P. G., and IRWINE, A. H. Experimental ureteral anastomosis. Brit J Urol: February 1966. 12. MULLIGAN, W., ROCK, J., and EASTERDAY, C. L. Use of polyethylene in tubop!asty. Fertil Steril 4:428, 1953.