Comparative Tubal Occlusion: Rigid and Spring-Loaded Clips*

Vol. 23, No.9, September 1972 Printed in U.SA.

FERTILITY AND STERILITY

Copyright © 1972 by The Williams & Wilkins Co.

COMPARATIVE TUBAL OCCLUSION: RIGID AND SPRING-LOADED CLIPS* J. F. HULKA, M.D.,

AND

K. F. OMRAN, M.D., DR.P.H.

Department of Obstetrics and Gynecology,The School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514

In earlier reports 1 the authors described preliminary attempts to occlude the uterotubal junction from within by means of chemical and physical agents, as well as attempts to occlude the tube from without with a variety of clips. The present report will describe histologic and fertility studies based on this experience to evaluate two specific methods of tubal occlusion from without: a tantalum clip and a spring-loaded clip.

were used, 5 animals underwent tantalum clip application, and 5 animals underwent spring-loaded clip application.

MATERIALS AND METHODS

Sows of proven fertility were used in all experiments. The studies were performed at the North Carolina State Laboratory of Reproductive Physiology in Raleigh through the kindness of Dr. Ulberg and the skilled assistance of his graduate students and staff. The protocol for each sow is given in Fig. 1. Control animals underwent laparotomy, manipulation of the uterotubal junction (specifically, aspiration of fertilized eggs by irrigation of the uterus with saline forced toward a needle placed in the tube), but did not undergo any further tubal surgery. Tantalum clips were applied according to the directions of the manufacturer (see Fig. 2, large clip). As a result of previous studies (see Fig. 2) a spring-loaded clip was designed (see Figs. 3-5). These clips were applied approximately 2 cm. away from the sow uterotubal junction. Five control animals Received April 14, 1972. * Supported in part by the Rockefeller Foundation and the Agency for International Development.

633

RESULTS

Table 1 indicates the results of the fertility studies comparing various clips. As can be seen, the group of sows that had tantalum clips applied achieved pregnancy at the same rate as the controls; the animals which had spring clips applied did not become pregnant. When these observations were obtained the investigators were concerned that the clips had been somehow applied inadequately. Therefore, from those animals with tantalum clips that had become pregnant, the uterotubal tissues were obtained at slaughter and excised without dissection. Mter fixation in formalin, the specimens were arranged on a glass plate in such a manner to give an end on view of the clip by X-ray. The distance between the clips and the X-ray film was comparable to distances involved in human X-ray studies. Figure 6 represents the X-rays of the end of views of the six clips correctly applied to the 3 animals in which pregnancies were noted. On gross dissection of these specimens, all the clips were surrounding the tube. Histologic sections were taken through the area underneath the clip, and Fig. 7 shows a cross-section of the tissue within the tantalum clip. Proper application of the tantalum clip results in preservation of the continuity of the tubal lumen and epithelium, even though the

634

musculature is interrupted at the point of the clip. Gross dissection of the tubes occluded with the spring-loaded clip revealed surprising findings. In all of the animals, the tubes had undergone complete division, with the proximal and distal stump no longer in continuity and separated by at least the distance of the clip (4 mm.) if not completely bound apart in other directions (see Fig. 8). Inflammatory response varied from a minimal FERTILITY

TE ST

0

SYSTE M

'"'

SLOUGH~

! "'"'"

~~,-t~~ ~~ ~ ~ ~

MATE IN HE AT

Vol. 23

HULKA AND OMRAN

REC OVER OCCLLIDE

2·4 CELL u·T EGGS .NNCTION

lt--v-3\" ls--nt--3 MATE IN HE AT

~ (rt '

RE·MAT E IN HEAT

r~

'vMt3 ~

CO\J NTC L AN O

F~i~~~~~~:L

FIG. 1. Experimental protocol followed in all sow studies to evaluate fertility subsequent to UTJ treatment.

coating of the area over the clip to adhesions involving adjacent tubal structures, and were somewhat more noticeable with this clip than was noted with the tantalum clip. In one instance, the clip had been drawn back through the uterotubal junction and was found inside the lumen of the sow uterus, being held there by strands from the stump of the tube (Fig. 9). The authors are at a loss to explain the physiology of this remarkable finding. Currently, 7 more sows (utilizing the entire supply of 13 prototype clips available at this time) are under prolonged observation with monthly hand-mating to evaluate the possibility of spontaneous restoration of fertility. At the time of writing, no pregnancies have occurred in 4 months; all of the 5 control sows have become pregnant. These results are significant to the 0.0013 level using the Fisher Exact Test. Three chimpanzees at the Delta Regional Primate Center

EXPERIMENTAL TUBOCCLUSION CLIPS

c:::. Small Tantalum Clip

c

Large Tantalum Clip

Plastic Coated Spring Prototype

---

Stainless Steel Spring

,........ Modified Steel Spring

Inexpensive Steel Spring Prototype

FIG. 2. Experimental tubocclusion clips. Both small and large tantalum clips were placed on sow uterotubal junctions in previous studies. 1 The large tantalum clip in this illustration is the one currently in use in humans. Pregnancies occurred with this clip as documented in the text. The stainless steel spring and the modified steel spring are clips designed pnmarily for hemostasis during surgery; these clips were dis!)laced by tubal peristalsis in earlier studies. Further study of these spring clips was therefore discontinued. These clips are currently made by the Week Instrument Company. The plastic coated spring prototype was designed bv Dr. Frank Shubeck and Mr. George Clemens. When applied, dense adhesions were noted arouna the cup aespite plastic coating of the springs. 'fhe clips were also dislodged by peristalsis trom the tubes. The inexpensive steel spring prototype proved to be far too angular for abdominal tolerance and was discontinued. This was designed by the author and Mr. George Clemens. The high dislodgment rate noted with these early desigris led to the toothe
September 1972

635

COMPARATIVE TUBAL OCCLUSION

FIG. 3. Open view of the clip used in these studies. Both uppe~ and lower iaws are made of Lexan, a hard plastic which does not change contour over time. The spring is made of stainless steel which is biocompatible. The white object at the end of the spring is a Silastic plug used to fill dead space created when the spring is closed (see next illustration). The spring and clip jaws are designed so that the spring in the open position holds the jaws open.

FIG. 5. Clip in closed position on uterotubal junction. No slippage or hemorrhage is evident. TABLE 1. Pregnancies following TubocclUsion

Control Tantalum clip Spring clip

FIG. 4. Closed clip. The upper jaw is closed on the tube by passing a rod over its upper surface (see Fig. 12). The stainless steel spring is then pushed forward and locks into place on the long end of the jaws. The Silastic filler comes to fill the dead space between the jaws and the stainless steel. The opposing jaw surfaces do not completely come into contact at the time of application, but rather a steady pressure is maintained on the tissue to cause eventual necrosis.

have had three clips applied to one tube each to study the adhesions to be expected in the primate uterotubal anatomy, somewhat more exposed to omentum and bowel than in the sow. This collaborative effort was accomplished with the gen-

No. of Animals

No. pregnant

5 5 5

3 3 0

FIG. 6, X-~y of six clip applications in three sows that had become p~ant. As can be seen, the clips are well applied, have a maximum of 1 mm. distance between tile -opposing surfaces.Tlie X-ray was_ tak~n at .apprQxim_ately the. ~aril~ _di!!tliI!~!l as woula occur if the human subject had X-rays of applied clips in her body.

erous assistance of Dr. Thomas Clewe. The clips have been indwelling for 6 months and these aimals have not been sacrificed to date.

636

HULKA AND OMRAN

Vol. 23

FIG. 7. Cross-section of the tissue within the tantalum clip. The actual distance between the clip jaws was calculated at 0.8 mm. Within this distance, it can be seen that the muscular tissue has been completely destroyed, but that the isthmic portion of the tube lumen has opened and contains intact epithelium and a functional lumen. DISCUSSION

These studies were undertaken to study the gross and histologic changes ocurring when rigid (tantalum) and

spring-loaded clips were used to occlude fallopian tubes. Also, a preliminary evaluation of fertility subsequent to the use of these clips was carried out. The authors

September 1972

COMPARATIVE TUBAL OCCLUSION

637

FIG. 8. Gross appearance after 3 months. Area of uterotubal junction was excised intact and fixed in formalin. Minimal adhesions and fibrinous coating of the clips were noted in this animal. Tubal separation was complete in these and all other tubes both grossly and microscopically.

were surprised to find that with a tantalum clip, applied in the same manner as in the human, pregnancies occurred in these experimental animals at the same rate as in controls. On the other hand, spring-loaded clips caused complete necrosis of both musculature and tubal mucosa, and complete division of the tube over a 3-month period with no pregnancies during this process. The spring-loaded clip was designed to be applied through a l-cm. diameter laparoscope (Figs. 10-12). The laparoscope illustrated is a prototype model. The implications of these studies to

human investigation at this point are worthy of discussion. In a large series reported at conferences but as yet unpublished, Dr. Gutierrez in Mexico has applied clips to over 4000 humans and has reported very low preg~ancy rates. Specifically, in one study of over 1000 patients, 3 had subsequent pregnancies, a most acceptable failure rate. 2 These observations are in direct contrast to the small study in sows herein reported. This could be interpreted as indicating incomplete followup on the part of the human study, or, more probably, an illustration that the sow is a severe model

638

HULKA AND OMRAN

Vol. 23

FIG. 9. Cross-section of the first centimeter of a uterus. The entire specimen was fixed in formalin; the uterus was entered through the incision in the upper right hand comer of the specimen and the clip removed from the lumen of the uterus (empty square space in the middle of the specimen). As can be seen, inflammatory reaction to this foreign body inside the uterus is minimal. How this large object got through the uterotubal junction when applied as illustrated in Fig. 5 is beyond the author's ability to explain.

for testing technics of fertility control in humans. The discrepancy between our results and those reported clinically by Dr. Gutierrez suggests strongly that the ultimate study of control of the reproducFIG. 10. Laparoscope designed by Mr. George tive system of man must be man. Animal Clemens-and the author to apply this clip through a models carry with them inherent differen- 1-cm. trocar (shown in the middle ofthe instrument). ces between animals and humans which The upper two rings activate a bar which closes the jaw of the clip, the lower rings activate a bar will make extrapolation of data, both which pushes the spring over the closed clip. The positive or, in this case, possibly false entire instrument can be held and operated with one hand. negative, misleading. It is the author's current opinion that lumen of both humans and sows, dethe spring-loaded clip described can be creasing the chance of failure of this clip applied through a laparoscope under local anesthesia, and will eliminate the possiin terms of subsequent pregnancies, bility of a continuing patency in the tubal both intrauterine and ectopic. 3 These

September 1972

639

COMPARATIVE TUBAL OCCLUSION SUMMARY AND CONCLUSION

" , ,; i% :;'*'i:r ~~" 1110\

'" ""

-"

1f~

'~#:t' ~

If

FIG., 11. Arrangement of the clip in the laparoscopic clip applicator. The optics can be seen to the right of the clip application area. These optics allow for over 50% of the visual field to be free for visualization of the cJip and tube during application. For exploration of the pelvis prior to application of the clip, 'both bars are withdrawn and all but a 45° pie-shaped section of the visual field is available for exploration of the pelvis and identification of the tubes.

An exploratory series of tests has been carried out comparing rigid tantalum and spring-loaded clips designed for tubal occlusion. Five control animals were used, 5 animals underwent tantalum clip application, and 5 animals underwent spring clip application. Three controls became pregnant, 3 sows with tantalum clips became pregnant, none of the sows with spring clips became pregnant. Patency of the tubal lumen was maintained with the rigid clips but was eliminated with spring clips. A laparoscope designed to apply the spring clips under local anesthesia is described. Implications regarding reported clinical trials and future human investigation are discussed. REFERENCES

K. F., AND HULKA, J. F. Tubal occlusion: A comparative study. Int J Fertil 15:226, 1970. 2. GUTIERREZ, A. Culdoscopy as an Aid in Family Planning. A Workshop for Female Sterilization: Prognosis for Simplified Out-patient Procedures. December 1-3, 1971. Airlie, Virginia. Proceedings to be published by the Battelle Human Affairs Research Center, Seattle, Washington. 3. NEUWIRTH, R. D. Ectopic pregnancy following tubal occlusion by tantalum clip application as performed by the Gutierrez method. Personal communication.

1. FIG. 12. Closed position of the clip in the laparoscopic clip applicator. The jaws of the clamp have been closed with the upper bar and the spring closed over the jaws with the lower bar. When both bars are brought back to the open position, the clip is free of its metal channel and remains on the tube.

theoretical concerns will have to be ultimately tested in a comparative trial i~ humans with adequate followup.

OMRAN,