Nidation Index Research Articles

Effects of cornual catheterization on uterotubal histology and function

To assess histologic damage and functional impairment following coaxial tubal catheterization. Prospective randomized controlled study. Research laboratory. Ninety-two female New Zealand rabbits. Tubal cannulation and mating. Rabbits randomized for placement of unilateral catheter and guide wire (group 1), unilateral catheter and guide wire plus falloposcope (group 2), and catheterization as in group 1 or 2 but using a cage catheter (groups 3 and 4, respectively). A fifth group consisted of rabbits with tubal perforations. Rabbits were killed at 2 or 4 weeks after catheterization or after mating. The sixth group consisted of only control rabbits. Only one catheterized tube in groups 1 and 3 showed inflammation, fibrosis, or edema. None of the tubes manifested ciliary loss. Serosal tubal adhesions were identified in two tubes in group 1, in one in group 3, in three tubes in group 5, and one in the control group. The nidation index in control and nonperforated catheterized tubes ranged from 72%-95% (not significant). Nidation index in tubes unintentionally perforated was 81%. Catheterization of the uterotubal junction and fallopian tube in rabbits does not cause long-term tubal damage or impair tubal function.

Postoperative adhesion formation and reproductive outcome using Interceed after ovarian surgery: a randomized trial in the rabbit model.

The efficacy of an oxidized regenerated cellulose barrier (Interceed) in reducing postoperative adhesion formation and improving reproductive outcome after ovarian surgery was evaluated in a prospective randomized trial. Twenty-nine New Zealand White female rabbits were submitted to a mid-line laparotomy and a standardized surgical incision was made on both ovaries. At random, one ovary was entirely wrapped in a sheet of Interceed, whereas the contralateral ovary was left uncovered. Four weeks following surgery, the rabbits were mated with a male of proven fertility. Two weeks later, a second-look laparotomy was performed by a blinded observer who evaluated the incidence and score of adhesions, the number of corpora lutea in each ovary, the number of embryos in the ipsilateral uterine horn and also calculated the nidation index for each side. Adhesions were observed in 66% of Interceed-covered and in 97% of control ovaries (P < 0.0001). The adhesion score on the Interceed side was significantly lower than on the control side. The nidation index for the Interceed side was significantly higher than for the control side. The authors conclude that, in the rabbit model, Interceed significantly reduces the incidence and score of postoperative ovarian adhesions and significantly improves reproductive outcome.

Use of Fibrin Sealant for Reproductive Surgery: A Randomized Study in the Rabbit Model

The present study was undertaken to compare adhesion formation and reproductive outcome after reproductive surgery with or without the application of fibrin sealant. At laparotomy, the ovaries and uterine horns of 20 rabbits were longitudinally incised on the antimesenteric side using a monopolar microneedle. At random, one ovary and the ipsilateral uterine horn were covered with fibrin sealant, while those on the contralateral side were left uncovered without application of sutures. The rabbits were then mated, and 2 weeks later a second-look laparotomy was performed by a blinded observer. No statistically significant differences were found in postoperative adhesions, number of corpora lutea in each ovary, number of embryos in the ipsilateral uterine horn, and nidation index for each side. Fibrin sealant for conservative surgery does not appear to significantly affect either postoperative adhesion formation or reproductive outcome.

A new approach to methotrexate and lipiodol suspensions for ectopic pregnancy: preliminary in vitro and animal experiments.

To measure and evaluate the in vitro release of MTX from suspensions of methotrexate (MTX) and lipiodol (LPD), and to investigate the MTX concentration and fertility rate using an animal model. This study was divided into three components: a) An in vitro Release Study, b) Animal Study No. 1 (concentration of tissue and plasma levels), and c) Animal Study No. 2 (fertility rate after MTX suspension). The releasing rate in vitro was more rapid with MTX-S (MTX dissolved in saline) than with either MTX-LPD (MTX dissolved in lipiodol) or MTX-LPD-PC (MTX suspended in lipiodol and phosphatidylcholin, i.e., MTX suspension). The tissue concentration tended to be higher with an MTX suspension than with MTX-S. There was no significant difference in the fertility rate or the nidation index among the 3 groups (Groups 1, 2, and 3). The injection of an MTX suspension is useful for increasing the tissue concentration and maintaining the long-term effectiveness of MTX, and this technique might offer a new approach in the treatment of ectopic pregnancy (EP) or in second-line therapy for persistent EP.

Laparoscopy versus laparotomy for ovarian conservative surgery: A randomized trial in the rabbit model

Our purpose was to compare postoperative adhesion formation and reproductive outcome after the same ovarian surgical procedure performed by laparoscopy or laparotomy by means of microsurgical techniques. Twenty-eight New Zealand White female rabbits were randomly assigned to laparotomy or laparoscopy for the same standardized surgical procedure: both ovaries were grasped with atraumatic forceps and longitudinally incised on the antimesenteric side from the cortex to the hilum with a microelectrode delivering a tissue power density of 66,666 W/cm. The rabbits were then mated, and 2 weeks later a second-look laparotomy was performed by a blinded observer for the evaluation of postoperative adhesions, number of corpora lutea in each ovary, number of embryos in the ipsilateral uterine horn, and nidation index for each side. At second look no statistically significant differences were found in postoperative adhesion formation, number of corpora lutea, number of embryos, and nidation index between the laparoscopy and the laparotomy groups. Laparoscopy or laparotomy for ovarian conservative surgery do not appear significantly different in postoperative adhesion formation and reproductive outcome in the rabbit model.

Fibrin glue for reanastomosis of the Fallopian tube in the rabbit: adhesions and fertility

Fertility and adhesions were examined in 41 rabbits in three treatment groups following the construction of microsurgical anastomoses with fibrin glue and by conventional suturing techniques. The three types of treatment were: isthmic anastomoses without resection, ampullary anastomoses, isthmic anastomoses following resection of oviduct segments. There were no significant differences between the two methods of performing the anastomoses in any of the three groups with respect to number of ovulations, number of implantations, nidation index, and pregnancy rate. The extent of the formation of adhesions was also no different between the two types of anastomosis construction. From the functional point of view, fibrin glueing of the tubes can be considered as good as microsurgical suturing. Another study is planned to examine whether this is also true from the morphological viewpoint. It must be remarked that fibrin glueing does not appear to be suitable for anastomoses in which a lumen-adjusting technique is needed or for deep tubocornual or intramural anastomoses.

The effect of tubal injection of methotrexate on fertility in the rabbit

To investigate the fertility of rabbits after tubal injection of methotrexate (MTX). The side of injection of MTX was randomly decided in a prospective experimental trial. Fourteen female New Zealand White Rabbits were believed to be of normal reproductive status. Methotrexate or Ringer's solution were injected into the tubes of the rabbits. The nidation index was used to measure the fertility of the animals. The average nidation index of the control tubes was not statistically different of the one of the tubes treated with MTX. Tubal injection of MTX has no adverse effect on fertility of rabbits. It seems ethical to investigate tubal injection of MTX as an alternative to laparoscopic management of unruptured ectopic pregnancy in the human.

Rabbit endosalpinx suppresses ectopic implantation

This study was undertaken to elucidate the mechanism underlying the absence of oviductal ectopic pregnancies in infraprimates. Endosalpingeal circumferential grafts were substituted for endometrium in a group of rabbits. The endosalpingeal grafts interfered with implantation as evidenced by four observations: (1) The nidation indices were lowered, (2) no implantations occurred on the grafted endosalpinx, (3) unattached blastocysts were found in animals grafted with endosalpinx, and (4) the implantation sites were significantly smaller in uterine horns containing endosalpingeal grafts. These findings suggest the presence of a factor in rabbit endosalpinx that actively suppresses ectopic implantation in the oviduct.

An experimental study of tubo-ovarian function following restoration of patency in hydrosalpinges

The recovery of tubal function after restoration of patency in mechanically induced hydrosalpinges was studied in twenty sexually mature rabbits by correlating the morphological lesions of tubal damage and adhesion formation with the ovulatory function, pregnancy rate and nidation index at 2 and 4–8 weeks postoperative intervals. Two weeks after hydrosalpinx correction no implantations occurred although the oviducts had a patency rate of 63% and no or slight adhesions were present. From four weeks after hydrosalpinx correction implantations occurred. Morphological studies showed a partial or complete recovery of mucosal lesions in this group of rabbits. The number of ovulations correlated with the presence or absence of a moderate degree of postoperative adhesion formation.

Morphology and fertility after re-anastomosis of the rabbit fallopian tube with fibrin glue.

Morphology and fertility were studied in 20 female New Zealand White rabbits after re-anastomosis of the Fallopian tube with fibrin glue and conventional microsurgical techniques. All oviducts were patent postoperatively. No intraperitoneal adhesions were observed. There were no significant differences with regard to the number of corpora lutea, implantations and the nidation index. Morphological studies demonstrated a normal fold pattern and ciliation at the side of anastomosis in the sealed oviducts as well as in the sutured oviducts. No intraluminal fibrin deposits were found. For re-anastomosis of the Fallopian tube with fibrin glue, splinting is necessary. In some instances this may be related to a mucosal trauma. However, under optimal conditions the use of fibrin glue is equivalent to conventional microsurgical anastomosis of the oviduct. For tubocornual, ampullary--ampullary and isthmic--ampullary anastomoses with luminal disparity, fibrin glue seems to be inappropriate.

A comparison of three techniques for ovarian reconstruction

We compared three methods of ovarian reconstruction in 23 mature female New Zealand White rabbits. Each animal was its own control. The right ovary in each rabbit was incised and repaired by placing three 8-0 nylon sutures through and through the base of the defect (method A). The left ovary was repaired without these through-and-through sutures. In 16, hemostasis was achieved by microbipolar cautery (method B); in seven, hemostasis was achieved with three sutures placed entirely inside the defect (method B1). The cortex of each ovary was repaired identically by continous 8-0 nylon suture. Outcome was evaluated by laparoscopy 14 days after mating. Through-and-through sutures (right ovary) caused a significant increase in adhesion formation and decrease in nidation index. When these animals were put to death 14 weeks later, the right ovaries were significantly smaller. On the left, there was no difference in any outcome variable between methods B and B1. This study clearly shows the detrimental effect of through-and-through sutures for ovarian reconstruction.

Primary and secondary closure of ampullary salpingotomy compared in the rabbit

Because there is disagreement as to how linear ampullary salpingotomy should heal, primarily or secondarily, we compared the two methods with the use of rabbit oviducts in which conditions simulating ectopic pregnancy had been induced. Pregnancy rates (86% versus 75%), nidation indices (62% versus 54%), and percentage of adhesion-free tubes (50% versus 32%) were greater after primary closure, but these differences were not statistically significant. Ampullary tuboperitoneal fistulae occurred at the site of operation in 6.8% of tubes and impaired fertility (P less than 0.005).

Absorbable or Nonabsorbable Suture Material for Microsurgical Tubal Anastomosis

In 20 female rabbits the influence of absorbable and nonabsorbable suture material on microsurgical anastomosis of the oviduct was investigated. No significant superiority of polyglactin 910 over polypropylene could be demonstrated. Concerning histological reaction to the different suture materials as well as pregnancies (calculated by nidation indices) the results were comparable. The modern suture materials obviously do not influence the functional sequelae of microsurgical reanastomosis of the rabbit fallopian tube.

The effect of training in microsurgery

One of the most important and fundamental prerequisites for successful microsurgery is serious and adequate training. This article presents the effect of microsurgical training on the functional end result of reanastomosis in the rabbit fallopian tube and evaluates the appropriate duration of laboratory training. In 50 New Zealand White female rabbits a microsurgical reanastomosis of the fallopian tube in its isthmic portion was performed. The rabbits were divided into five groups. In the first group only 30% of the rabbits conceived on the side operated on. The nidation index was only 0.269 as compared to 0.831 for the control side. Improvement in microsurgical skill following 100 isthmic anastomoses resulted in a 100% pregnancy rate for the last group. The nidation indexes in this group were the same on the side operated on and on the control side, 0.774 and 0.702, respectively. Scanning electron microscopic examination of the anastomosis site revealed a progressive increase in patency rate and in the amount of apposed mucosal folds in the three groups. A training program is recommended, which should bring about a nidation index and pregnancy rate that should not differ from the side operated on to the control side.

OVA Transport and Fertility after Resection of the Oviductal Isthmus in Pigs

The effect upon the reproduction of total resection of the oviductal isthmus, including the uterotubal and ampullary-isthmus junctions followed by end-to-end ampullo-cornual anastomosis was studied in pigs. Normal cycling gifts of proved fertility were submitted to bilateral isthmus deletion (Group I). Other gilts were submitted only to unilateral isthmic resection, while their contralateral medial isthmus was transversally cut and reanastomosed (Group II). A significantly lower nidation index was obtained after bilateral isthmic resection. The gilts in Group I which did not become pregnant and those in Group II were successfully mated during forthcoming standing oestruses, and were in association to that slaughtered on days 3, 4, or 5 of the cycle, and the characteristics and location of ova were determined. Spermatozoa fertilized the ova, and those cleaved normally in the isthmic-resected tube as well as in the sham-operated oviducts. The isthmic-resected oviduct, however, did not transport cleaved ova into the uterus at the time expected as normal. The findings suggest that the fertilized pig ova cannot reach the uterus at the normal expected time in case of total absence of the isthmic part of the oviduct, resulting in impaired fertility.

Training in tubal microsurgery.

The restoration of normal tubo-ovarian function was investigated in a training programme using oviduct anastomosis in the rabbit as an experimental model. Ovulation rate, pregnancy rate, nidation index, implantation failure index and degree of adhesions were used as parameters. More than 100 anastomoses had to be performed to reach a perfect degree of atraumatic, function-restoring surgery. It is concluded that the most difficult aspect in female infertility surgery is not the use of the operating microscope but the experience in applying the principles of atraumatic surgery.

Conventional and simplified microsurgical isthmic tubal anastomosis compared in the rabbit

Because the fallopian tube has potential for spontaneous recanalization, a simplified technique for isthmic anastomosis has been previously proposed. This study compares the simplified technique, which uses only one suture to approximate the tube, with a conventional isthmic anastomosis. The nidation index and patency rate subsequent to these procedures on the rabbit oviduct were evaluated. The conventional anastomosis gave a significantly better nidation index (P less than 0.01) and a patency rate (P less than 0.05). Even when tubal patency was established with the simplified technique, the nidation index may have been less than with conventional anastomosis (P less than 0.07). Gynecologic microsurgeons should continue to strive for the best anatomic repair possible when performing isthmic anastomosis and not rely on the fallopian tube's potential for spontaneous recanalization.

Effect of lengthening the fallopian tube on fertility in the rabbit

The effect of surgically lengthening the rabbit oviduct was investigated. In the study group, a lengthened fallopian tube was created by division of the left fallopian tube at the ampullary-isthmic junction and the right fallopian tube at the uterotubal junction. The proximal left tube and the entire right tube were mobilized to the midline, and a microsurgical anastomosis was performed with 10-0 nylon. This formed a tube that was lengthened by approximately 50%, with doubling of the isthmic region. In the control group, both tubes were divided at the ampullary-isthmic junction, and the proximal left and distal right segments were joined to form a tube of normal length. The left ovary and ampulla were resected in both groups. After the animal had been bred, a second laparotomy was performed to assess adhesion formation, document tubal patency, and establish a nidation index. The median nidation index of the control group (N = 11) was 0.89, whereas that of the lengthened group (N = 7) was 0. The nidation indices of the two groups were different, with P < 0.01.

Histology and fertility after microsurgical anastomosis of the rabbit fallopian tube with nylon and polyglactin sutures

Polyglactin and nylon suture material were compared in microsurgical anastomosis of oviduct of rabbits with regard to the histologic reaction, adhesion formation, and nidation index. Thirty days after surgery, the tissue inflammatory response was very similar in both groups. At 90 days, polyglactin had been totally absorbed in 80% of the cases, and no inflammatory reaction persisted at the site of the suture. At this time, multinucleated giant cell reaction to nylon sutures was persistent but minimal. The results reveal no significant functional differences between oviduct reanastomosed with nylon versus polyglactin suture. No significant difference in subsequent fertility due to suture selection was demonstrated.

Ovum Capture and Fertility following Microsurgical Fimbriectomy in the Rabbit

Microsurgical fimbriectomy with removal of the fimbria ovarica was performed on one side in 19 rabbits. The other tube was left intact as a control. In 10 animals the new ostium was left free, some distance from the ovary. In the remainder, the ostium was fixed to the ovarian capsule. Three animals with a fixed ostium developed mild hydrosalpinx even though the neostomy was patent. Of the remaining 16 rabbits, 15 conceived and became pregnant in both uterine horns. There was no significant difference between nidation index on the two sides. It is concluded that intact fimbriae with a fimbria ovarica are not essential for normal ovum capture. It is therefore suggested that methods for clinical salpingostomy may require re-evaluation.