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Microsurgical reversal of tubal sterilization: a report on 1,118 cases
FERTILITY
AND
STERILITYE
Copyright
’ 1997 American
Published
by Elsevier
Vol. 68, No. 5, November
Society for Reproductive
Science
Medicine
Printed
on acid-fme
paper
1997
in U. S. A.
Inc.
Microsurgical reversal of tubal sterilization: a report on I,1 18 cases Seok Hyun Rim, M.D. Chang Jae Shin, M.D. Jung Gu Kim, M.D. Division of Reproductive Seoul National
Shin Yong Moon, M.D. Jin Yong Lee, M.D. Yoon Seok Chang, M.D. Endocrinology
and Infertility,
Department
of Obstetrics and Gynecology,
College of Medicine,
University, Seoul, Korea
Objective: To review and evaluate a series of patients who underwent microsurgical anastomosis of previously sterilized fallopian tubes. Design: Retrospective clinical study. Setting: Tertiary care academic center. Patient(s): In the 134-month span from January 1980 to February 1991,1,118 women were evaluated for microsurgical reversal of previous tubal sterilization. Main Outcome Measure(s): Clinical characteristics of patients, pregnancy rates (PRs), and factors influencing the outcome. Result(s): Of 1,118 patients, 633 (56.6%) had been sterilized by laparoscopic cautery. Loss of children was a leading reason for requesting tubal reversal. The mean interval between tubal sterilization and reversal was 51.9 months. Nine hundred twenty-two (82.5%) patients were followed up for >5 years. The overall PR after microsurgical tubal anastomosis was 54.8% (505 of 922) with a delivery rate of 72.5% (366 of 5051, and the estimated anatomical success rate was 88.2% (814 of 922). There was no statistically significant difference in the PR or in the interval from tubal reversal to conception among the different operative procedure groups. In addition, no statistically significant difference in the PR was observed regardless of the postoperative tubal length. However, the interval from operation to pregnancy decreased significantly as the postoperative tubal length increased. The pregnant patients (n = 505) were younger and had a longer postoperative tube than the nonpregnant patients (n = 417); these differences were statistically significant. Conclusion(s): The pregnancy rate after microsurgical reversal of tubal sterilization was not significantly correlated with the method and duration of sterilization, the operative procedure, or the postoperative tubal length. (Fertil Sterile 1997;68:865-70. 0 1997 by American Society for Reproductive Medicine.) Key Words: Tubal sterilization, microsurgical reversal, tubal anastomosis, pregnancy rate, factors influencing pregnancy rate
The prominence of permanent sterilization as a method of fertility control for many women has resulted from the ease and safety of the surgical procedures involved and the potential complications of other methods, such as oral contraceptives and intrauterine devices (IUDs). Tubal sterilization is currently one of the most popular forms of birth control in women in Korea. However, some women eventu-
Received February 12, 1997; revised and accepted July 22, 1997. Reprint requests: Seok Hyun Kim, M.D., Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Seoul National University Hospital, 28 YeongunDong, Chongno-Ku, Seoul 110-744, Korea (FAX: 82-2-742-2028). 0015-0282/97/$17.00 PI1 SOO15-0282(97)00361-O
ally regret their decision after they experience a change in their personal, social, or economic lives and request tubal anastomosis. With the increased number of women seeking tubal sterilization for contraception and the desire to regain the lost fertility, it can be anticipated that there will be a rise in the number of women requesting reversal of tubal sterilization. Recent advances in microsurgical techniques for tubal anastomosis using a higher magnification and atraumatic technique have resulted in a pregnancy rate (PR) of 57%-84% (l-4). Several studies have examined the characteristics of women who requested or obtained tubal anastomosis and the results of this procedure. 866
We describe our experience performing tubal anastomosis with a microsurgical technique in 1,118 patients and we review the clinical characteristics of patients, PRs, and factors influencing the outcome. MATERIALS AND METHODS
In the 134-month span from January 1, 1980, to February 28, 1991, 1,118 women were evaluated for microsurgical reversal of previous tubal sterilization in the Department of Obstetrics and Gynecology at Seoul National University Hospital. The Institutional Review Board of Seoul National University Hospital approved this study. A complete evaluation of the fertility potential of each woman requesting tubal anastomosis was performed, including obstetric history, pelvic examination, semen analysis, basal body temperature (BBT) chart with timed endometrial biopsy and/or determination of midluteal serum P level in some cases, postcoital test (PCT), hysterosalpingography (HSG), and diagnostic laparoscopy. Women with previous fimbriectomy, unresolved medical contraindications to pregnancy, or other absolute cause for infertility were excluded. Tubal anastomosis was performed bilaterally in all cases. Patients undergoing unilateral anastomosis were excluded from this study. Magnification (~6) was obtained by using a surgical microscopic system. A two-layer closure using a 7-O or 8-O polyglycolic acid suture was performed. Tissue handling was atraumatic, and tissues were kept moist at all times by constant saline irrigation. Unipolar electrocoagulation was always used for hemostasis. A splint of 2-O monofilament nylon was used and removed transcervically on the 7th postoperative day. Before final closure of the peritoneum, 200 mL of lactated Ringer’s solution containing 1 g of hydrocortisone and 5,000 U of heparin per liter was placed in the pelvic cavity. The length of fallopian tube after anastomosis was measured in such a way that the interstitial portion of tube was not included in the measurement. Prophylactic antibiotics and conjugated estrogen were administered postoperatively, but postoperative hydrotubation was not used. If the patient did not become pregnant by 12 months after surgery, HSG was recommended and performed for 151 patients. Nine hundred twenty-two (82.5%) patients were followed up for more than 5 years postoperatively. Statistical analysis was performed with use of Student’s t-test, x2 test, one-way analysis of variance (ANOVA), and Pearson’s correlation test, where appropriate. A P value of co.05 was considered to be statistically significant. 866
Kim et al. Microsurgical reversal of tubal sterilization
RJISULTS Patients Characteristics
The clinical profile of the 1,118 patients undergoing microsurgical tubal anastomosis was reviewed. At the time that reversal was requested, the mean age (+SD) was 31.8 ? 3.6 years (range, 21-43 years), the mean number (&SD) of living children was 1.2 2 0.8 (range, O-51, and the mean duration (+SD) of sterilization was 51.9 ? 30.0 months (range, 3- 185 months). The reasons for requesting reversal were loss of children in 50.8% (568 of 1,118), remarriage in 27.3% (305 of 1,118), and change of attitude in 21.5% (240 of 1,118). The main motivating factor for change of mind was a desire for sons. Tubal sterilization was performed by laparoscopic bipolar cauterization in 56.6% of cases (633 of l,llS>, by laparoscopic application of Yoon’s rings in 27.6% (308 of 1,118), by tubal ligation with Pomeroy’s method on cesarean section in 7.6% (85 of 1,118>, by tubal ligation via minilaparotomy in 3.2% (36 of 1,118), and by tubal ligation during puerperal period in 3.0% (34 of 1,118) (Table 1). Microsurgical Reversal Procedure
Among 1,118 microsurgical reversal procedures, there were 76 cases at the bilateral cornual-isthmic sites, 89 at the bilateral cornual-ampullar, 204 at the bilateral isthmic-isthmic, 361 at the bilateral isthmic-ampullar, and 43 at the bilateral ampullar-ampullar. In 345 cases (30.9%), reversal procedures were performed bilaterally at the different sites of each salpinx (Table 2). The length of fallopian tubes after anastomosis was measured in such a way that the interstitial tubal portion was not included in the measurement, and the longer one was chosen for analysis. The distribution of postoperative tubal length is shown in Table 2. Postoperative tubal length was analyzed by
Table 1 Postoperative Tubal Length by Method of Tubal Sterilization
Method
No. of patients
Laparoscopic TL Cautery Ring Cesarean section + TL Minilaparotomy TL Postnartum TL Others Total
941 633 308 85 36 34 22 1,118
Tubal length (cm) Mean 2 SD 6.6 6.3 7.1 7.0 6.4 7.4 5.7 6.6
5 ? + 2 k k 2 -t
1.3 1.4 1.3 1.4 1.3 1.3 1.8 1.4
Range 1.0-11.5 1.0-11.0 1.0-11.5 4.0-10.0 4.0-9.0 1.0-11.5 2.0-9.5 1.0-11.5
Note: TL = tubal ligation. Fertility and Sterility@
Table 2 Pregnancy Rates and Time Intervals From Operation to Pregnancy by Various Variables Time interval (mo)
Pregnancy Variable Method of tubal sterilization Laparoscopic TL Cautery Ring Cesarean section + TL Minilaparotomy TL Postpartum TL Others Duration of tubal sterilization (mo) 512 13-24 25-36 37-48 49-60 261 Tubal reversal procedure Bilateral C -1 Bilateral C-A Bilateral I-I Bilateral I-A Bilateral A-A Subtotal Postoperative tubal length (L) Lc3cm 3
Mean 2 SD
Range
8.3 8.8 7.2 10.7 8.3 9.0 26.5
2 8.2 t 8.7 k 7.0 2 7.9 2 7.1 2 10.6 k 14.5
l-56 l-56 l-40 l-46 l-29 2-44 3-41
56.6 50.6 58.8 48.5 53.5 52.5
6.9 10.8 7.2 8.5 11.8
-c 5 2 t 2
4.6 8.4 5.4 5.5 11.0
l-33 l-40 l-47 l-43 2-56
62.5 42.6 46.2 53.8 55.3 65.9 53.2 54.5 54.8
23.0 12.1 7.3 11.1 7.4 7.9 5.2 5.8 8.7
2 13.2 -+ 9.9 2 5.0 + 7.7 t 5.3 t 5.7 2 2.6 t 2.8 t 8.7
l-40 l-40 l-30 l-56 l-37 l-47 1-14 2-11 l-56
No. of patients
No. of patients
PR (%I
770 537 233 72 33 33 14
432 133 36 19 14 4
56.1 55.7 57.1 50.0 57.6 42.4 28.6
83 131 141 150 141 276
46 61 75 79 84 160
55.4 46.6 53.2 52.7 59.6 58.0
76 89 204 361
43 45 120 175 23 406
8 47 145 221 237 176 77 11 922
5 20 67 119 131 116 41 6 505
299
Note: TL = tubal ligation; C = cornual; I = isthmic; A = ampullar.
using the method of tubal sterilization: 6.3 + 1.4 cm in the laparoscopic bipolar cauterization group, 7.1 f 1.3 cm in the laparoscopic rings group, 7.0 2 1.4 cm in the tubal ligation on cesarean section group, 6.4 k 1.3 cm in the tubal ligation via minilaparotomy group, and 7.4 + 1.3 cm by tubal ligation during puerperal period group (Table 1).
The mean age (+SD) was significantly lower in the pregnant group than in the nonpregnant group (30.9 t 3.5 versus 31.6 t 3.5 years). There was,
however, no statistically significant difference in the mean duration (?SD) of sterilization between the pregnant and nonpregnant groups. There was a statistically significant difference in the postoperative tubal length between the pregnant and nonpregnant groups (6.7 t 1.5 cm versus 6.5 +- 1.4 cm) (Table 4). The pregnancy rates did not correlate with the method of tubal sterilization. The PR was 55.7% (299 of 537) in the laparoscopic bipolar cauterization group, 57.1% (133 of 233) in the laparoscopic rings group, 50.0% (36 of 72) in the tubal ligation on cesarean section group, 57.6% (19 of 33) in the minilaparotomy tubal ligation group, and 42.4% (14 of 33) in the postpartum tubal ligation group. The interval from tubal reversal to conception diagnosed by ultrasonography varied without statistical significance according to the type of tubal sterilization. The mean (+SD) interval was 8.8 -+ 8.7 months in the laparoscopic bipolar cauterization group, 7.2 ? 7.0 months in the laparoscopic rings group, 10.7 + 7.9 months in the tubal ligation on cesarean section group, 8.3 -+ 7.1 months in the minilaparotomy tubal ligation group, and 9.0 2 10.6
Vol. 68, No. 5, November 1997
Kim et al. Microsurgical
Pregnancies
Of 1,118 patients, 922 (82.5%) were followed up for >5 years, and 505 achieved 585 pregnancies with a PR per patient of 54.8% (505 of 922). Four hundred seven patients had a term delivery, 11 had a preterm delivery, 47 had an ectopic pregnancy (EP), 109 had a spontaneous abortion, 9 had an artificial abortion by the patient’s will, and 2 had hydatidiform mole (Table 3). Factors
Influencing
PR
reversal of tubal sterilization
867
Table 3 Outcomes of Pregnancy After Microsurgical Tubal Reversal No. of women (%l
Outcome Delivery Term Preterm Ectopic pregnancy Ectopic PR by procedure of tubal reversal Bilateral I-A (n = 361) Bilateral I-I (n = 204) Bilateral C-I (n = 76) Bilateral C-A (n = 89) Bilateral A-A (n = 43) Spontaneous abortion Artificial abortion Hydatidiform mole Total
366 (72.51 356 (70.51 10 (2.0) 42 (8.3)
418 (71.5) 407 (69.6) 11 (1.9) 47 (8.1)
18 (4.99) 4 (1.961 3 (3.95) 4 (4.491 1 (2.33) 90 (17.8) 6 (1.2) 1 (0.2) 505 (100.0)
109 (18.6) 9 (1.5) 2 (0.3) 585 (100.0)
months in the postpartum tubal ligation group (Table 4). The pregnancy rates also did not correlate with the duration of tubal sterilization as shown in Table 2. There was no statistically significant difference in the PR or the interval from tubal reversal to conception among the different operative procedure groups. The PRs were 56.6% (43 of 76) in the bilateral cornual-isthmic procedure group, 50.6% (45 of 89) in the bilateral cornual-ampullar group, 58.8% (120 of 204) in the bilateral isthmic-isthmic group, 48.5% (175 of 361) in the bilateral isthmic-ampullar group, and 53.5% (23 of 43) in the bilateral ampullar-ampullar group (Table 2). There was also no statistically significant difference in the ectopic PR among the different operative procedure groups. The ectopic PRs were 3.95% (3 of 76) in the bilateral cornual-isthmic group, 4.49% (4 of 89) in the bilateral cornual-ampullar group, 1.96% (4 of 204) in the bilateral isthmic-isthmic
Table 4 Comparison Between Pregnant and Nonpregnant Groups After Microsurgical Tubal Reversal
Duration of tubal sterilization (mo) Postoperative tubal length (cm)
Pregnant group
Nonpregnant group
505 30.9 2 3.5* (21-41) 49.5 ? 28.6 (3-168) 6.7 2 1.5t (1.0-11.0)
417 31.6 ? 3.5* (21-43) 50.2 ? 31.0 (3-179) 6.5 k 1.47 (2.5-11.5)
Note: Values are means k SD unless otherwise indicated. *P < 0.01. t P < 0.05.
868
Kim et al. Microsurgical
rz5
No. of women (o/o)*
Note: PR = pregnancy rate; I = isthmic; A = ampullar; C = cornual. * Numbers including the second or third pregnancy.
No. of patients Age W
ClPR
reversal of tubal sterilization
Postoperativetuballength(cm)
1
Figure 1 Pregnancy rates and time intervals from operation to pregnancy according to the postoperative tubal length. The pregnancy rates did not correlate with the postoperative tubal length, but the time interval correlated inversely (P < 0.01 by Pearson’s correlation test). PR = pregnancy rate; TI = time interval.
group, 4.99% (18 of 361) in the bilateral isthmicampullar group, and 2.33% (1 of 43) in the bilateral ampullar-ampullar group (Table 3). No statistically significant difference in the PR was observed, regardless of the postoperative tubal length. However, the interval from operation to pregnancy decreased significantly as the postoperative tubal length increased (P < 0.01) (Fig. 1). Postoperative
Tubal Patency Rate
Of 417 patients who failed to conceive, 151 underwent a follow-up HSG, and tubal patency in at least unilateral tube was confirmed in 112 cases (74.2%), including 58 bilaterally patent and 54 unilaterally patent cases. For the microsurgical reversal of tubal sterilization, the anatomical success rate was estimated as 88.2% (814 of 922) by the equation of [pregnant cases + patent cases in HSG + cases in which pregnancy was not achieved and HSG was not performed X patent rate in HSGY922, that is, [505 + 112 + (922 - 505 - 151) x 112/1511/922. The final success rate of achieving pregnancy was 54.8% (505 of 922) in this study.
There has been .a tremendous increase in the rate of female sterilization in Korea; more than two million procedures have been performed during the past 15 years. In women undergoing sterilization procedures, the average number of living children was 1.2, and the average age was 31.8 years (5). It is conceivable that as women select voluntary sterilizaFertility and Sterility@
tion procedures at lower parity and younger ages, the potential demand for reversal of tubal sterilization will increase. Schwyhart and Kutner (6) reviewed 22 studies and reported that the percentage of patients regretting voluntary sterilization ranged from 1.3% to 15%. In our series, the most common reason for requesting microsurgical tubal anastomosis for reversal of tubal sterilization was loss of children, comprising 50.8% of total requests. Other major reasons given in our series were remarriage and change of attitude, representing 27.3% and 21.5%, respectively. However, remarriage has become the leading reason for reversal of tubal sterilization recently in Korea. Since the introduction of microsurgical techniques for tubal surgery by Swolin (7), an increasing number of surgeons have used these techniques, and microsurgery appears to offer the best chance of successful reversal of tubal sterilization. Through the use of microsurgery, previously sterilized tubes can be repaired, and approximately 60% of patients operated on subsequently achieve a term pregnancy under ideal circumstances (8). The true reversibility rate of a particular sterilization technique can be ascertained only by including all women who consulted a gynecologist primarily for that purpose. Some women are dissuaded from continuing to pursue tubal reversal after infertility studies, such as HSG and diagnostic laparoscopy, and general preoperative tests are performed. In a retrospective study, Antoine et al. (9) analyzed 377 requests for reversal of tubal sterilization and noted that 40% were turned down because of too much tubal destruction. The only criterion for successful reversal of tubal sterilization is a term pregnancy. It is generally known that the results are influenced by the amount of remaining tube, the location of tubal anastomosis, and the skill and experience of the surgeon (10,111. The greater the tubal destruction in sterilization procedure, the less the chance of successful tubal reconstruction. Henderson (10) reported that the isthmus-isthmus anastomosis was the most successful in terms of PRs (81%), and the length in centimeters of the longest remaining tube multiplied by a factor of 10 gave a close approximation of term delivery rate. For example, when the length of the longest tube was 5 cm, the term delivery rate observed was 47%. This latter observation, once the length of a remaining tube has been measured accurately by prior laparoscopy (although this is not necessarily confirmed at the time of a microsurgical procedure), is especially helpful for giving a particular patient the predicted
term delivery rate if she were to undergo a microscopic tubal anastomosis. Seiler (11) claimed, however, that where postoperative tubal length was >4 cm, this was not a factor in the outcome. In our study, although the interval from operation to pregnancy decreased significantly as the postoperative tubal length increased, the PRs did not correlate with the postoperative tubal length. Furthermore, the PRs also did not correlate with the site of tubal anastomosis. The following different incidences of EP after tubal reversal have been reported by some investigators: 2% by Winston (12), 4% by Silber and Cohen (13), 5.2% by Chang and Kim (14), and 6% by Cantor and Riggal (15). In this series, the incidence of EP (8.1%) was higher compared with these figures. In addition to no statistically significant difference among the different operative procedure groups, the ectopic PR was not more likely to have occurred where there was luminal disparity, such as cornualisthmic, cornual-ampullar, and isthmic-ampullar groups as opposed to where there was no luminal disparity, such as isthmic-isthmic and ampullarampullar groups. It is somewhat difficult to evaluate the influence of a patient’s age on the outcome of tubal reversal. Older patients usually have longer intervals between sterilization and tubal reversal, ovulatory disturbances, and older partners. In the absence of such cofactors, counseling about the medical and social implications of becoming a parent at ~40 years of age would be appropriate. In this study, because the PR after tubal reversal was 49.8% (103 of 207) in patients who were ~35 years, 49.4% (42 of 85) in those who were 237 years, and 50.0% (6 of 12) in those who were 240 years, respectively, the age of the patients did not significantly influence the outcome of tubal reversal. Vasquez et al. (16) performed scanning electron microscopic studies on 26 specimens and generally noted increased abnormalities with increasing intervals between sterilization and tubal reversal. These included flattening of longitudinal mucosal folds, deciliation, polyposis, and other disorders in the tubal isthmus where chronic occlusion occurred. Scanning electron microscopy studies also have shown a relative atrophy of epithelium in the proximal tubal stumps in women sterilized >5 years before tubal reversal. The secretory and ciliary action of tubal cells are important in sperm and ovum transport, and a longstanding unrelieved intratubal pressure in these closed stumps may result in decreased fertility. However, as was the case with other studies, there was no difference in the PR among groups with different intervals between sterilization and reversal,
Vol. 68, No. 5, November 1997
Kim et al.
Microsurgical reversal of tubal sterilization
889
and the duration of tubal sterilization did not appear to play important roles in this study. For tubal sterilization, new methods of tubal interruption aimed at minimizing the amount of tissue destruction have been developed. Although not evaluated for a significant length of time, Silastic Yoon’s rings (17) and Hulka clips (18) appear to offer the highest probability of a reversal of tubal sterilization because tissue damage is relatively minimal with the laparoscopic application of rings and clips. Electrocoagulation, especially unipolar, seems to result in the most extensive tubal destruction besides its attendant risks of thermal injury to the surrounding structures and is least likely to be successfully reversed. In our series, there was no significant correlation between the sterilization method and the success rate. However, a larger series should be examined to determine whether the sterilization method plays any role in the ultimate success rate for intrauterine pregnancy. There are some limitations in this study. First, a confounding factor may have had an undiscovered effect (i.e., the significant effect of one factor on another was not considered). The site of tubal anastomosis at the time of reversal as well as the postoperative tubal length may be predetermined by the particular sterilization method. Second, other factors (such as the skill and experience of the surgeon) that may have more influence over the outcome were not included. Although adjunctive measures such as intraperitoneal corticosteroids and splints were used, the clinical value of these measures has not been proven. In conclusion, tubal reversal of previously sterilized fallopian tubes using the microsurgical technique appears to offer a good chance of pregnancy, but the PR after tubal anastomosis was not correlated with the method and duration of sterilization, the operative procedure, or the postoperative tubal length. REFERENCES 1. Gomel V. Microsurgical reversal of female sterilization: a reappraisal. Fertil Steril 1980;33:587-97.
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of tubal
sterilization
2. Meldrum DR. Microsurgical tubal reanastomosis: the role of splints. Obstet Gynecol 1981;57:613-9. 3. Grunert GM, Drake TS, Takaki NK. Microsurgical reanastomosis of the fallopian tubes for reversal of sterilization. Obstet Gynecol 1981;58:148-51. 4. Lauerson NH. Patient selection and preoperative counseling. In: Reyniak JV, Lauerson NH, editors. Principles of microsurgical techniques in infertility. New York: Plenum Medical Books, 1982:95-119. 5. Bai BC, Park CM, Kwak HM, Whang YW. Governmentfunding program on reversal of tubal sterilization. Asia Oceania J Obstet Gynecol 1992; 18:73-80. 6. Schwyhart WR, Kutner SJ. A reanalysis of female reaction to contraceptive sterilization. J Nerv Ment Dis 1973; 156:354-63. 7. Swolin K. Contribution to the surgical treatment of female sterility: experimental and clinical studies. Acta Obstet Gynecol Stand 1967;46 Suppl 14:1-20. 8. Siegler AM, Hulka J, Peretz A. Reversibility of female sterilization. Fertil Steril 1985;43:499-510. 9. Antoine JM, Dubuisson JB, Tournaire M, Lerat H. Request for reversal of tubal sterilization: survey conducted by the National College of French Gynecologists and Obstetricians. J Gynecol Obstet Biol Reprod 1983; 12:583-91. 10. Henderson SR. The reversibility of female sterilization with the use of microsurgery: a report of 102 patients with more than one year follow-up. Am J Obstet Gynecol 1984; 149:5765. 11. Seiler JC. Factors influencing the outcome of microsurgical tubal ligation reversal. Am J Obstet Gynecol 1983;146: 292-8. 12. Winston RML. Microsurgery of the fallopian tube: from fantasy to reality. Fertil Steril 1980;34:521-30. 13. Silber SJ, Cohen R. Microsurgical reversal of female sterilization: the role of tubal length. Fertil Steril 1980;33:598-601. 14. Chang YS, Kim JG. Microsurgical reversal of tubal sterilization. Asia Oceania J Obstet Gynecol 1986; 12:457-63. 15. Cantor R, Riggal FC. The choice of sterilization procedure according to its potential reversibility with microsurgery. Fertil Steril 1979;31:9-12. 16. Vasquez G, Winston RML, Boeckx W, Brosens I. Tubal lesions subsequent to sterilization and their relation to fertility after attempts at reversal. Am J Obstet Gynecol 1990; 138:86-92. 17. Yoon IB, King T, Parmley TH. A two-year experience with the Falope ring sterilization procedure. Am J Obstet Gynecol 1977;127:109-12. 18. Hulka JF, Mercer JP, Fishburne JI, Kumarasamy T, Omran KF, Philips JM, et al. Spring clip sterilization: one-year follow-up of 1,079 cases. Am J Obstet Gynecol 1976; 125:103943.
Fertility
and Sterility@
AND
STERILITYE
Copyright
’ 1997 American
Published
by Elsevier
Vol. 68, No. 5, November
Society for Reproductive
Science
Medicine
Printed
on acid-fme
paper
1997
in U. S. A.
Inc.
Microsurgical reversal of tubal sterilization: a report on I,1 18 cases Seok Hyun Rim, M.D. Chang Jae Shin, M.D. Jung Gu Kim, M.D. Division of Reproductive Seoul National
Shin Yong Moon, M.D. Jin Yong Lee, M.D. Yoon Seok Chang, M.D. Endocrinology
and Infertility,
Department
of Obstetrics and Gynecology,
College of Medicine,
University, Seoul, Korea
Objective: To review and evaluate a series of patients who underwent microsurgical anastomosis of previously sterilized fallopian tubes. Design: Retrospective clinical study. Setting: Tertiary care academic center. Patient(s): In the 134-month span from January 1980 to February 1991,1,118 women were evaluated for microsurgical reversal of previous tubal sterilization. Main Outcome Measure(s): Clinical characteristics of patients, pregnancy rates (PRs), and factors influencing the outcome. Result(s): Of 1,118 patients, 633 (56.6%) had been sterilized by laparoscopic cautery. Loss of children was a leading reason for requesting tubal reversal. The mean interval between tubal sterilization and reversal was 51.9 months. Nine hundred twenty-two (82.5%) patients were followed up for >5 years. The overall PR after microsurgical tubal anastomosis was 54.8% (505 of 922) with a delivery rate of 72.5% (366 of 5051, and the estimated anatomical success rate was 88.2% (814 of 922). There was no statistically significant difference in the PR or in the interval from tubal reversal to conception among the different operative procedure groups. In addition, no statistically significant difference in the PR was observed regardless of the postoperative tubal length. However, the interval from operation to pregnancy decreased significantly as the postoperative tubal length increased. The pregnant patients (n = 505) were younger and had a longer postoperative tube than the nonpregnant patients (n = 417); these differences were statistically significant. Conclusion(s): The pregnancy rate after microsurgical reversal of tubal sterilization was not significantly correlated with the method and duration of sterilization, the operative procedure, or the postoperative tubal length. (Fertil Sterile 1997;68:865-70. 0 1997 by American Society for Reproductive Medicine.) Key Words: Tubal sterilization, microsurgical reversal, tubal anastomosis, pregnancy rate, factors influencing pregnancy rate
The prominence of permanent sterilization as a method of fertility control for many women has resulted from the ease and safety of the surgical procedures involved and the potential complications of other methods, such as oral contraceptives and intrauterine devices (IUDs). Tubal sterilization is currently one of the most popular forms of birth control in women in Korea. However, some women eventu-
Received February 12, 1997; revised and accepted July 22, 1997. Reprint requests: Seok Hyun Kim, M.D., Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Seoul National University Hospital, 28 YeongunDong, Chongno-Ku, Seoul 110-744, Korea (FAX: 82-2-742-2028). 0015-0282/97/$17.00 PI1 SOO15-0282(97)00361-O
ally regret their decision after they experience a change in their personal, social, or economic lives and request tubal anastomosis. With the increased number of women seeking tubal sterilization for contraception and the desire to regain the lost fertility, it can be anticipated that there will be a rise in the number of women requesting reversal of tubal sterilization. Recent advances in microsurgical techniques for tubal anastomosis using a higher magnification and atraumatic technique have resulted in a pregnancy rate (PR) of 57%-84% (l-4). Several studies have examined the characteristics of women who requested or obtained tubal anastomosis and the results of this procedure. 866
We describe our experience performing tubal anastomosis with a microsurgical technique in 1,118 patients and we review the clinical characteristics of patients, PRs, and factors influencing the outcome. MATERIALS AND METHODS
In the 134-month span from January 1, 1980, to February 28, 1991, 1,118 women were evaluated for microsurgical reversal of previous tubal sterilization in the Department of Obstetrics and Gynecology at Seoul National University Hospital. The Institutional Review Board of Seoul National University Hospital approved this study. A complete evaluation of the fertility potential of each woman requesting tubal anastomosis was performed, including obstetric history, pelvic examination, semen analysis, basal body temperature (BBT) chart with timed endometrial biopsy and/or determination of midluteal serum P level in some cases, postcoital test (PCT), hysterosalpingography (HSG), and diagnostic laparoscopy. Women with previous fimbriectomy, unresolved medical contraindications to pregnancy, or other absolute cause for infertility were excluded. Tubal anastomosis was performed bilaterally in all cases. Patients undergoing unilateral anastomosis were excluded from this study. Magnification (~6) was obtained by using a surgical microscopic system. A two-layer closure using a 7-O or 8-O polyglycolic acid suture was performed. Tissue handling was atraumatic, and tissues were kept moist at all times by constant saline irrigation. Unipolar electrocoagulation was always used for hemostasis. A splint of 2-O monofilament nylon was used and removed transcervically on the 7th postoperative day. Before final closure of the peritoneum, 200 mL of lactated Ringer’s solution containing 1 g of hydrocortisone and 5,000 U of heparin per liter was placed in the pelvic cavity. The length of fallopian tube after anastomosis was measured in such a way that the interstitial portion of tube was not included in the measurement. Prophylactic antibiotics and conjugated estrogen were administered postoperatively, but postoperative hydrotubation was not used. If the patient did not become pregnant by 12 months after surgery, HSG was recommended and performed for 151 patients. Nine hundred twenty-two (82.5%) patients were followed up for more than 5 years postoperatively. Statistical analysis was performed with use of Student’s t-test, x2 test, one-way analysis of variance (ANOVA), and Pearson’s correlation test, where appropriate. A P value of co.05 was considered to be statistically significant. 866
Kim et al. Microsurgical reversal of tubal sterilization
RJISULTS Patients Characteristics
The clinical profile of the 1,118 patients undergoing microsurgical tubal anastomosis was reviewed. At the time that reversal was requested, the mean age (+SD) was 31.8 ? 3.6 years (range, 21-43 years), the mean number (&SD) of living children was 1.2 2 0.8 (range, O-51, and the mean duration (+SD) of sterilization was 51.9 ? 30.0 months (range, 3- 185 months). The reasons for requesting reversal were loss of children in 50.8% (568 of 1,118), remarriage in 27.3% (305 of 1,118), and change of attitude in 21.5% (240 of 1,118). The main motivating factor for change of mind was a desire for sons. Tubal sterilization was performed by laparoscopic bipolar cauterization in 56.6% of cases (633 of l,llS>, by laparoscopic application of Yoon’s rings in 27.6% (308 of 1,118), by tubal ligation with Pomeroy’s method on cesarean section in 7.6% (85 of 1,118>, by tubal ligation via minilaparotomy in 3.2% (36 of 1,118), and by tubal ligation during puerperal period in 3.0% (34 of 1,118) (Table 1). Microsurgical Reversal Procedure
Among 1,118 microsurgical reversal procedures, there were 76 cases at the bilateral cornual-isthmic sites, 89 at the bilateral cornual-ampullar, 204 at the bilateral isthmic-isthmic, 361 at the bilateral isthmic-ampullar, and 43 at the bilateral ampullar-ampullar. In 345 cases (30.9%), reversal procedures were performed bilaterally at the different sites of each salpinx (Table 2). The length of fallopian tubes after anastomosis was measured in such a way that the interstitial tubal portion was not included in the measurement, and the longer one was chosen for analysis. The distribution of postoperative tubal length is shown in Table 2. Postoperative tubal length was analyzed by
Table 1 Postoperative Tubal Length by Method of Tubal Sterilization
Method
No. of patients
Laparoscopic TL Cautery Ring Cesarean section + TL Minilaparotomy TL Postnartum TL Others Total
941 633 308 85 36 34 22 1,118
Tubal length (cm) Mean 2 SD 6.6 6.3 7.1 7.0 6.4 7.4 5.7 6.6
5 ? + 2 k k 2 -t
1.3 1.4 1.3 1.4 1.3 1.3 1.8 1.4
Range 1.0-11.5 1.0-11.0 1.0-11.5 4.0-10.0 4.0-9.0 1.0-11.5 2.0-9.5 1.0-11.5
Note: TL = tubal ligation. Fertility and Sterility@
Table 2 Pregnancy Rates and Time Intervals From Operation to Pregnancy by Various Variables Time interval (mo)
Pregnancy Variable Method of tubal sterilization Laparoscopic TL Cautery Ring Cesarean section + TL Minilaparotomy TL Postpartum TL Others Duration of tubal sterilization (mo) 512 13-24 25-36 37-48 49-60 261 Tubal reversal procedure Bilateral C -1 Bilateral C-A Bilateral I-I Bilateral I-A Bilateral A-A Subtotal Postoperative tubal length (L) Lc3cm 3
Mean 2 SD
Range
8.3 8.8 7.2 10.7 8.3 9.0 26.5
2 8.2 t 8.7 k 7.0 2 7.9 2 7.1 2 10.6 k 14.5
l-56 l-56 l-40 l-46 l-29 2-44 3-41
56.6 50.6 58.8 48.5 53.5 52.5
6.9 10.8 7.2 8.5 11.8
-c 5 2 t 2
4.6 8.4 5.4 5.5 11.0
l-33 l-40 l-47 l-43 2-56
62.5 42.6 46.2 53.8 55.3 65.9 53.2 54.5 54.8
23.0 12.1 7.3 11.1 7.4 7.9 5.2 5.8 8.7
2 13.2 -+ 9.9 2 5.0 + 7.7 t 5.3 t 5.7 2 2.6 t 2.8 t 8.7
l-40 l-40 l-30 l-56 l-37 l-47 1-14 2-11 l-56
No. of patients
No. of patients
PR (%I
770 537 233 72 33 33 14
432 133 36 19 14 4
56.1 55.7 57.1 50.0 57.6 42.4 28.6
83 131 141 150 141 276
46 61 75 79 84 160
55.4 46.6 53.2 52.7 59.6 58.0
76 89 204 361
43 45 120 175 23 406
8 47 145 221 237 176 77 11 922
5 20 67 119 131 116 41 6 505
299
Note: TL = tubal ligation; C = cornual; I = isthmic; A = ampullar.
using the method of tubal sterilization: 6.3 + 1.4 cm in the laparoscopic bipolar cauterization group, 7.1 f 1.3 cm in the laparoscopic rings group, 7.0 2 1.4 cm in the tubal ligation on cesarean section group, 6.4 k 1.3 cm in the tubal ligation via minilaparotomy group, and 7.4 + 1.3 cm by tubal ligation during puerperal period group (Table 1).
The mean age (+SD) was significantly lower in the pregnant group than in the nonpregnant group (30.9 t 3.5 versus 31.6 t 3.5 years). There was,
however, no statistically significant difference in the mean duration (?SD) of sterilization between the pregnant and nonpregnant groups. There was a statistically significant difference in the postoperative tubal length between the pregnant and nonpregnant groups (6.7 t 1.5 cm versus 6.5 +- 1.4 cm) (Table 4). The pregnancy rates did not correlate with the method of tubal sterilization. The PR was 55.7% (299 of 537) in the laparoscopic bipolar cauterization group, 57.1% (133 of 233) in the laparoscopic rings group, 50.0% (36 of 72) in the tubal ligation on cesarean section group, 57.6% (19 of 33) in the minilaparotomy tubal ligation group, and 42.4% (14 of 33) in the postpartum tubal ligation group. The interval from tubal reversal to conception diagnosed by ultrasonography varied without statistical significance according to the type of tubal sterilization. The mean (+SD) interval was 8.8 -+ 8.7 months in the laparoscopic bipolar cauterization group, 7.2 ? 7.0 months in the laparoscopic rings group, 10.7 + 7.9 months in the tubal ligation on cesarean section group, 8.3 -+ 7.1 months in the minilaparotomy tubal ligation group, and 9.0 2 10.6
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Pregnancies
Of 1,118 patients, 922 (82.5%) were followed up for >5 years, and 505 achieved 585 pregnancies with a PR per patient of 54.8% (505 of 922). Four hundred seven patients had a term delivery, 11 had a preterm delivery, 47 had an ectopic pregnancy (EP), 109 had a spontaneous abortion, 9 had an artificial abortion by the patient’s will, and 2 had hydatidiform mole (Table 3). Factors
Influencing
PR
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Table 3 Outcomes of Pregnancy After Microsurgical Tubal Reversal No. of women (%l
Outcome Delivery Term Preterm Ectopic pregnancy Ectopic PR by procedure of tubal reversal Bilateral I-A (n = 361) Bilateral I-I (n = 204) Bilateral C-I (n = 76) Bilateral C-A (n = 89) Bilateral A-A (n = 43) Spontaneous abortion Artificial abortion Hydatidiform mole Total
366 (72.51 356 (70.51 10 (2.0) 42 (8.3)
418 (71.5) 407 (69.6) 11 (1.9) 47 (8.1)
18 (4.99) 4 (1.961 3 (3.95) 4 (4.491 1 (2.33) 90 (17.8) 6 (1.2) 1 (0.2) 505 (100.0)
109 (18.6) 9 (1.5) 2 (0.3) 585 (100.0)
months in the postpartum tubal ligation group (Table 4). The pregnancy rates also did not correlate with the duration of tubal sterilization as shown in Table 2. There was no statistically significant difference in the PR or the interval from tubal reversal to conception among the different operative procedure groups. The PRs were 56.6% (43 of 76) in the bilateral cornual-isthmic procedure group, 50.6% (45 of 89) in the bilateral cornual-ampullar group, 58.8% (120 of 204) in the bilateral isthmic-isthmic group, 48.5% (175 of 361) in the bilateral isthmic-ampullar group, and 53.5% (23 of 43) in the bilateral ampullar-ampullar group (Table 2). There was also no statistically significant difference in the ectopic PR among the different operative procedure groups. The ectopic PRs were 3.95% (3 of 76) in the bilateral cornual-isthmic group, 4.49% (4 of 89) in the bilateral cornual-ampullar group, 1.96% (4 of 204) in the bilateral isthmic-isthmic
Table 4 Comparison Between Pregnant and Nonpregnant Groups After Microsurgical Tubal Reversal
Duration of tubal sterilization (mo) Postoperative tubal length (cm)
Pregnant group
Nonpregnant group
505 30.9 2 3.5* (21-41) 49.5 ? 28.6 (3-168) 6.7 2 1.5t (1.0-11.0)
417 31.6 ? 3.5* (21-43) 50.2 ? 31.0 (3-179) 6.5 k 1.47 (2.5-11.5)
Note: Values are means k SD unless otherwise indicated. *P < 0.01. t P < 0.05.
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rz5
No. of women (o/o)*
Note: PR = pregnancy rate; I = isthmic; A = ampullar; C = cornual. * Numbers including the second or third pregnancy.
No. of patients Age W
ClPR
reversal of tubal sterilization
Postoperativetuballength(cm)
1
Figure 1 Pregnancy rates and time intervals from operation to pregnancy according to the postoperative tubal length. The pregnancy rates did not correlate with the postoperative tubal length, but the time interval correlated inversely (P < 0.01 by Pearson’s correlation test). PR = pregnancy rate; TI = time interval.
group, 4.99% (18 of 361) in the bilateral isthmicampullar group, and 2.33% (1 of 43) in the bilateral ampullar-ampullar group (Table 3). No statistically significant difference in the PR was observed, regardless of the postoperative tubal length. However, the interval from operation to pregnancy decreased significantly as the postoperative tubal length increased (P < 0.01) (Fig. 1). Postoperative
Tubal Patency Rate
Of 417 patients who failed to conceive, 151 underwent a follow-up HSG, and tubal patency in at least unilateral tube was confirmed in 112 cases (74.2%), including 58 bilaterally patent and 54 unilaterally patent cases. For the microsurgical reversal of tubal sterilization, the anatomical success rate was estimated as 88.2% (814 of 922) by the equation of [pregnant cases + patent cases in HSG + cases in which pregnancy was not achieved and HSG was not performed X patent rate in HSGY922, that is, [505 + 112 + (922 - 505 - 151) x 112/1511/922. The final success rate of achieving pregnancy was 54.8% (505 of 922) in this study.
There has been .a tremendous increase in the rate of female sterilization in Korea; more than two million procedures have been performed during the past 15 years. In women undergoing sterilization procedures, the average number of living children was 1.2, and the average age was 31.8 years (5). It is conceivable that as women select voluntary sterilizaFertility and Sterility@
tion procedures at lower parity and younger ages, the potential demand for reversal of tubal sterilization will increase. Schwyhart and Kutner (6) reviewed 22 studies and reported that the percentage of patients regretting voluntary sterilization ranged from 1.3% to 15%. In our series, the most common reason for requesting microsurgical tubal anastomosis for reversal of tubal sterilization was loss of children, comprising 50.8% of total requests. Other major reasons given in our series were remarriage and change of attitude, representing 27.3% and 21.5%, respectively. However, remarriage has become the leading reason for reversal of tubal sterilization recently in Korea. Since the introduction of microsurgical techniques for tubal surgery by Swolin (7), an increasing number of surgeons have used these techniques, and microsurgery appears to offer the best chance of successful reversal of tubal sterilization. Through the use of microsurgery, previously sterilized tubes can be repaired, and approximately 60% of patients operated on subsequently achieve a term pregnancy under ideal circumstances (8). The true reversibility rate of a particular sterilization technique can be ascertained only by including all women who consulted a gynecologist primarily for that purpose. Some women are dissuaded from continuing to pursue tubal reversal after infertility studies, such as HSG and diagnostic laparoscopy, and general preoperative tests are performed. In a retrospective study, Antoine et al. (9) analyzed 377 requests for reversal of tubal sterilization and noted that 40% were turned down because of too much tubal destruction. The only criterion for successful reversal of tubal sterilization is a term pregnancy. It is generally known that the results are influenced by the amount of remaining tube, the location of tubal anastomosis, and the skill and experience of the surgeon (10,111. The greater the tubal destruction in sterilization procedure, the less the chance of successful tubal reconstruction. Henderson (10) reported that the isthmus-isthmus anastomosis was the most successful in terms of PRs (81%), and the length in centimeters of the longest remaining tube multiplied by a factor of 10 gave a close approximation of term delivery rate. For example, when the length of the longest tube was 5 cm, the term delivery rate observed was 47%. This latter observation, once the length of a remaining tube has been measured accurately by prior laparoscopy (although this is not necessarily confirmed at the time of a microsurgical procedure), is especially helpful for giving a particular patient the predicted
term delivery rate if she were to undergo a microscopic tubal anastomosis. Seiler (11) claimed, however, that where postoperative tubal length was >4 cm, this was not a factor in the outcome. In our study, although the interval from operation to pregnancy decreased significantly as the postoperative tubal length increased, the PRs did not correlate with the postoperative tubal length. Furthermore, the PRs also did not correlate with the site of tubal anastomosis. The following different incidences of EP after tubal reversal have been reported by some investigators: 2% by Winston (12), 4% by Silber and Cohen (13), 5.2% by Chang and Kim (14), and 6% by Cantor and Riggal (15). In this series, the incidence of EP (8.1%) was higher compared with these figures. In addition to no statistically significant difference among the different operative procedure groups, the ectopic PR was not more likely to have occurred where there was luminal disparity, such as cornualisthmic, cornual-ampullar, and isthmic-ampullar groups as opposed to where there was no luminal disparity, such as isthmic-isthmic and ampullarampullar groups. It is somewhat difficult to evaluate the influence of a patient’s age on the outcome of tubal reversal. Older patients usually have longer intervals between sterilization and tubal reversal, ovulatory disturbances, and older partners. In the absence of such cofactors, counseling about the medical and social implications of becoming a parent at ~40 years of age would be appropriate. In this study, because the PR after tubal reversal was 49.8% (103 of 207) in patients who were ~35 years, 49.4% (42 of 85) in those who were 237 years, and 50.0% (6 of 12) in those who were 240 years, respectively, the age of the patients did not significantly influence the outcome of tubal reversal. Vasquez et al. (16) performed scanning electron microscopic studies on 26 specimens and generally noted increased abnormalities with increasing intervals between sterilization and tubal reversal. These included flattening of longitudinal mucosal folds, deciliation, polyposis, and other disorders in the tubal isthmus where chronic occlusion occurred. Scanning electron microscopy studies also have shown a relative atrophy of epithelium in the proximal tubal stumps in women sterilized >5 years before tubal reversal. The secretory and ciliary action of tubal cells are important in sperm and ovum transport, and a longstanding unrelieved intratubal pressure in these closed stumps may result in decreased fertility. However, as was the case with other studies, there was no difference in the PR among groups with different intervals between sterilization and reversal,
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and the duration of tubal sterilization did not appear to play important roles in this study. For tubal sterilization, new methods of tubal interruption aimed at minimizing the amount of tissue destruction have been developed. Although not evaluated for a significant length of time, Silastic Yoon’s rings (17) and Hulka clips (18) appear to offer the highest probability of a reversal of tubal sterilization because tissue damage is relatively minimal with the laparoscopic application of rings and clips. Electrocoagulation, especially unipolar, seems to result in the most extensive tubal destruction besides its attendant risks of thermal injury to the surrounding structures and is least likely to be successfully reversed. In our series, there was no significant correlation between the sterilization method and the success rate. However, a larger series should be examined to determine whether the sterilization method plays any role in the ultimate success rate for intrauterine pregnancy. There are some limitations in this study. First, a confounding factor may have had an undiscovered effect (i.e., the significant effect of one factor on another was not considered). The site of tubal anastomosis at the time of reversal as well as the postoperative tubal length may be predetermined by the particular sterilization method. Second, other factors (such as the skill and experience of the surgeon) that may have more influence over the outcome were not included. Although adjunctive measures such as intraperitoneal corticosteroids and splints were used, the clinical value of these measures has not been proven. In conclusion, tubal reversal of previously sterilized fallopian tubes using the microsurgical technique appears to offer a good chance of pregnancy, but the PR after tubal anastomosis was not correlated with the method and duration of sterilization, the operative procedure, or the postoperative tubal length. REFERENCES 1. Gomel V. Microsurgical reversal of female sterilization: a reappraisal. Fertil Steril 1980;33:587-97.
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2. Meldrum DR. Microsurgical tubal reanastomosis: the role of splints. Obstet Gynecol 1981;57:613-9. 3. Grunert GM, Drake TS, Takaki NK. Microsurgical reanastomosis of the fallopian tubes for reversal of sterilization. Obstet Gynecol 1981;58:148-51. 4. Lauerson NH. Patient selection and preoperative counseling. In: Reyniak JV, Lauerson NH, editors. Principles of microsurgical techniques in infertility. New York: Plenum Medical Books, 1982:95-119. 5. Bai BC, Park CM, Kwak HM, Whang YW. Governmentfunding program on reversal of tubal sterilization. Asia Oceania J Obstet Gynecol 1992; 18:73-80. 6. Schwyhart WR, Kutner SJ. A reanalysis of female reaction to contraceptive sterilization. J Nerv Ment Dis 1973; 156:354-63. 7. Swolin K. Contribution to the surgical treatment of female sterility: experimental and clinical studies. Acta Obstet Gynecol Stand 1967;46 Suppl 14:1-20. 8. Siegler AM, Hulka J, Peretz A. Reversibility of female sterilization. Fertil Steril 1985;43:499-510. 9. Antoine JM, Dubuisson JB, Tournaire M, Lerat H. Request for reversal of tubal sterilization: survey conducted by the National College of French Gynecologists and Obstetricians. J Gynecol Obstet Biol Reprod 1983; 12:583-91. 10. Henderson SR. The reversibility of female sterilization with the use of microsurgery: a report of 102 patients with more than one year follow-up. Am J Obstet Gynecol 1984; 149:5765. 11. Seiler JC. Factors influencing the outcome of microsurgical tubal ligation reversal. Am J Obstet Gynecol 1983;146: 292-8. 12. Winston RML. Microsurgery of the fallopian tube: from fantasy to reality. Fertil Steril 1980;34:521-30. 13. Silber SJ, Cohen R. Microsurgical reversal of female sterilization: the role of tubal length. Fertil Steril 1980;33:598-601. 14. Chang YS, Kim JG. Microsurgical reversal of tubal sterilization. Asia Oceania J Obstet Gynecol 1986; 12:457-63. 15. Cantor R, Riggal FC. The choice of sterilization procedure according to its potential reversibility with microsurgery. Fertil Steril 1979;31:9-12. 16. Vasquez G, Winston RML, Boeckx W, Brosens I. Tubal lesions subsequent to sterilization and their relation to fertility after attempts at reversal. Am J Obstet Gynecol 1990; 138:86-92. 17. Yoon IB, King T, Parmley TH. A two-year experience with the Falope ring sterilization procedure. Am J Obstet Gynecol 1977;127:109-12. 18. Hulka JF, Mercer JP, Fishburne JI, Kumarasamy T, Omran KF, Philips JM, et al. Spring clip sterilization: one-year follow-up of 1,079 cases. Am J Obstet Gynecol 1976; 125:103943.
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