Data collection
This study was reviewed and approved by the Human Ethical Committee of the University of Teikyo Hospital (Trial registration number: 20–094). The deidentified medical records of 150 female patients who underwent laparoscopic surgeries, performed after obtaining informed consent, from June 1, 2015, to December 31, 2021, were reviewed retrospectively, and the 22 cases were excluded for the following reasons: peritoneal ectopic pregnancy (9 cases), miscarriage from fallopian tube (8 cases), no detection of pregnancy tissue (3 cases), ovarian ectopic pregnancy (1 case) and uterine horn pregnancy (1 case). We extracted data on representative patient characteristics, such as age, delivery history, presenting symptoms, and physical data, from medical records. In particular, in all patients, serum hCG levels were examined several times, including before and after surgery, and we extracted these data. To evaluate the failure rates of laparoscopic surgeries, we extracted the data on PT (13 cases), in which patients were diagnosed per rising or plateauing serum hCG levels postoperatively and needed to be treated by intramuscular methotrexate injection (IMI).
Analysis methods
First, to compare the rates of PT between laparoscopic salpingostomy and salpingectomy, we divided the patients into two groups according to these treatment methods. In our hospital, the choice between these two methods depended largely on the patient’s situation, and the numbers were approximately equal. In only 6 cases, tubal pregnancy rupture was detected during surgery. In these two groups, we compared the 19 indexes shown in Table 1 by using Student's t-test, Pearson's chi-square test and the Mann–Whitney U test. By referring to a previous study evaluating the influence of the ratio of serum hCG levels before and after laparoscopic salpingostomy on the possibility of PT 9, we also compared this index (“hCG ratio” in Table 1). Second, we tried to evaluate the risk factors for PT, especially to detect the predictive values of preoperative serum hCG levels. Then, four approximate cut-offs values were used for serum hCG levels: 2000, 4000, 6000 and 8000 mIU/mL. For each of these four parameters, we performed similar analyses. We first analysed the 62 patients who underwent laparoscopic salpingostomy and then analysed all 128 patients. To control for confounding factors, we divided the patients into two groups according to the presence or absence of each factor and performed multivariate logistic regression analysis. In this analysis, we assessed the influence of the following 14 factors: 1) Advanced age, defined as an age ≥ 38 years; 2) High body mass index (BMI), defined as a BMI ≥ 25 (kg/m2); 3) Nulliparity, defined as no previous delivery; 4) Embryo transfer, defined as cases in which the patients became pregnant after embryo transfer; 5) Abnormal bleeding, defined as patients with abnormal vaginal bleeding caused by TEP; 6) Abdominal pain, defined as patients with abdominal pain caused by TEP; 7): Pelvic haematoma, defined as cases in which pelvic haematoma was detected by TVUS before surgery or during surgery; 8) Foetal heartbeat, defined as cases in which foetal heartbeat was detected by TVUS; 9) Isthmic tubal pregnancy, defined as cases in which isthmic tubal pregnancy was diagnosed during surgery; 10) Abdominal adhesion, defined as abdominal adhesion detected by laparoscopic inspection immediately after the start of surgery; 11) Salpingostomy; 12) High hCG, defined as a serum hCG level ≥ 2000, 4000, 6000, or 8000 mIU/mL; 13) Coexistent leiomyoma, defined as leiomyoma detected by laparoscopic inspection; and 14) Coexistent endometriosis, defined as endometriosis detected by laparoscopic inspection. Since the average age of the patients was 33.4 ± 4.8 years and since over 40% of the included patients became pregnant after infertility treatments, “Advanced age” was defined as patients aged 38 years or older with reference to a previous report 13. Statistical analyses were performed using Microsoft Excel (Microsoft Corporation, Redmond, WA) and JMP version 12 for Windows (SAS Institute, Inc., Tokyo, Japan) to determine the correlations between patient characteristics and the failure of laparoscopic surgery. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated to determine the strengths of the correlations. P < 0.05 was considered statistically significant.
Table 1
Comparison of patient characteristics between laparoscopic salpingostomy and salpingectomy.
|
Total
|
Salpingostomy (n = 62)
|
Salpingectomy (n = 66)
|
P value
|
Age
|
33.4 ± 4.8 (20–44, n = 128)
|
32.0 ± 4.5 (20–43, n = 62)
|
34.8 ± 4.7 (22–44, n = 66)
|
< 0.01
|
BMI
|
21.3 ± 2.8 (17.1–29.9, n = 128)
|
21.3 ± 2.9 (17.2–29.9, n = 62)
|
21.3 ± 2.7 (17.1–28.4, n = 66)
|
NS
|
Blood loss
|
126.4 ± 237.5 (0-1334, n = 128)
|
104.5 ± 229.3 (0-1334, n = 62)
|
147.0 ± 245.0 (0-1200, n = 66)
|
NS
|
Operation time
|
54.1 ± 20.1 (25–144, n = 128)
|
48.6 ± 12.3 (31–100, n = 62)
|
59.3 ± 24.2 (25–144, n = 66)
|
< 0.01
|
Treatment period
|
32.4 ± 17.9 (9-110, n = 128)
|
37.2 ± 22.4 (9-110, n = 62)
|
27.8 ± 10.3 (10–66, n = 66)
|
< 0.01
|
Average hCG
|
6528.1 ± 11513.8
(2.9-91673.2, n = 128)
|
3477.4 ± 3493.0
(2.9-18550.1, n = 62)
|
9393.8 ± 15177.3
(126.2-91673.2, n = 66)
|
< 0.01
|
Median hCG
|
2879.5
|
2117
|
4093.4
|
< 0.05
|
hCG ratio
|
0.38 ± 0.16 (0.10–1.18, n = 121)
|
0.41 ± 0.18 (0.11–1.18, n = 59)
|
0.35 ± 0.13 (0.10–0.94, n = 62)
|
NS
|
Embryo transfer
|
23.4% (n = 30/128)
|
3.2% (n = 2/62)
|
42.4% (n = 28/66)
|
< 0.01
|
Nulliparity
|
72.7% (n = 93/128)
|
79.0% (n = 49/62)
|
66.7% (n = 44/66)
|
NS
|
Abnormal bleeding
|
49.2% (n = 63/128)
|
56.5% (n = 35/62)
|
42.4% (n = 28/66)
|
NS
|
Abdominal pain
|
36.7% (n = 47/128)
|
37.1% (n = 23/62)
|
36.4% (n = 24/66)
|
NS
|
Pelvic haematoma
|
46.9% (n = 60/128)
|
48.4% (n = 30/62)
|
45.5% (n = 30/66)
|
NS
|
Foetal heartbeat
|
14.1% (n = 18/128)
|
8.1% (n = 5/62)
|
19.7% (n = 13/66)
|
NS
|
Isthmic tubal pregnancy
|
18.8% (n = 24/128)
|
12.9% (n = 8/62)
|
24.2% (n = 16/66)
|
NS
|
Abdominal adhesion
|
35.2% (n = 45/128)
|
32.3% (n = 20/62)
|
37.9% (n = 25/66)
|
NS
|
Persistent trophoblast
|
10.2% (n = 13/128)
|
19.4% (n = 12/62)
|
1.5% (n = 1/66)
|
< 0.01
|
Coexistent leiomyoma
|
14.8% (n = 19/128)
|
6.5% (n = 4/62)
|
22.7% (n = 15/66)
|
< 0.01
|
Coexistent endometriosis
|
7.0% (n = 9/128)
|
8.1% (n = 5/62)
|
6.1% (n = 4/66)
|
NS
|
After dividing 128 patients into two groups according to laparoscopic surgical methods, we compared 19 representative indexes. In this analysis, eight indexes, namely, “age”, “operation time”, “treatment period”, “average hCG”, “median hCG”, “embryo transfer”, “persistent trophoblast” and “coexistent leiomyoma”, showed significant differences.
Abbreviations: BMI: body mass index, NS: no significance, hCG: human chorionic gonadotropin.
Serum hCG level reduction rate
To estimate the appropriate postoperative follow-up period, we created linear regression lines based on the scatter plot of the association between reduction rates of serum hCG levels and elapsed time after surgery (laparoscopic salpingostomy: n = 236, laparoscopic salpingectomy: n = 289) by using the ordinary least-squares method with Microsoft Excel. In this analysis, 13 cases with PT were excluded. These plots did not include data below the detection sensitivity (laparoscopic salpingostomy: n = 7, laparoscopic salpingectomy: n = 4). We calculated the indexes in as follows: 1) we divided the serum hCG levels postoperatively by these levels immediately before the operation and 2) calculated the Log10 values. The formula used was Log10 (serum hCG level after/before operation (mIU/mL)). The relationship between this logarithmic index and elapsed time after surgery (days) was plotted. Then, by referring to the slopes of these regression lines, we estimated each required follow-up period for patients with laparoscopic salpingostomy or salpingectomy.