Ultrasound-guided transcervical forceps extraction of unruptured interstitial pregnancy

Authors

  • J-W Ahn,

    1. Department of Obstetrics and Gynaecology, University of Ulsan College of Medicine, Ulsan University Hospital, Ulsan, Korea
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  • S-J Lee,

    Corresponding author
    1. Department of Obstetrics and Gynaecology, University of Ulsan College of Medicine, Ulsan University Hospital, Ulsan, Korea
    2. Department of Obstetrics and Gynaecology, Hallym University, Dongtan Sacred Heart Hospital, Hwaseong, Korea
    • Correspondence: S-J Lee, Ulsan University Hospital, 290-3 Jeonha-dong Dong-gu Ulsan 682-714, Korea. Email exsjlee@hanmail.net

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  • SH Lee,

    1. Department of Obstetrics and Gynaecology, University of Ulsan College of Medicine, Ulsan University Hospital, Ulsan, Korea
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  • SP Kang,

    1. Health Promotion Centre, the Catholic University of Korea Yeouido St Mary's Hospital, Seoul, Korea
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  • H-S Won

    1. Department of Obstetrics and Gynaecology, University of Ulsan College of Medicine, Asan Medical Centre, Seoul, Korea
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  • Correction added on 23 May 2013, after first online publication: author affiliations for S-J Lee and SH Lee were incorrect, these have now been corrected.

Abstract

This report introduces a method for ultrasound-guided transcervical forceps extraction (UTCE) of unruptured interstitial pregnancies; this method does not necessitate elective caesarean delivery for future pregnancies. This report also compares this technique with conventional methods. A retrospective review was conducted involving 16 women treated for interstitial pregnancies. Among these women, UTCE was successfully performed in six of 16 women, with only one woman requiring additional intervention; conventional treatment was performed in the other ten women. UTCE is a safe, effective and minimally invasive option for treating interstitial pregnancies and should be considered as an alternative treatment modality.

Introduction

An interstitial pregnancy is an ectopic pregnancy that is implanted in the interstitial portion of the fallopian tube, i.e. the tubal segment that traverses the muscular wall of the uterus.[1] Conventional surgical interventions inevitably involve a uterine myometrial incision, such as cornuostomy/salpingotomy, cornual excision, cornual wedge resection, mini-cornual excision, or hysterectomy. Subsequently, there is an increased risk of uterine rupture during the course of future pregnancies, for which an elective caesarean delivery is usually recommended.[2, 3]

A less invasive surgical approach for resolving interstitial pregnancies is necessary to reduce direct myometrial injury during treatment and to minimise the risk of requiring elective caesarean delivery in future pregnancies. For this reason, ultrasound-guided transcervical forceps extraction (UTCE) was designed to avoid myometrial injury during treatment. The objectives of this study were to introduce UTCE as a new, minimally invasive surgical method for resolving unruptured interstitial pregnancies and to report the use of this method in comparison with conventional treatment methods.

Methods

A retrospective review was conducted of all interstitial pregnancies diagnosed at our institution between 1 March 2008 and 31 December 2011. The electronic data for women diagnosed with interstitial pregnancies were collected and analysed according to the women's demographic characteristics and clinical findings. Interstitial pregnancy was diagnosed using transvaginal ultrasonographic examination and quantitative serum β-human chorionic gonadotrophin (β-hCG) levels. On ultrasonographic examination, an interstitial pregnancy appears as a gestational sac eccentric to an empty endometrial cavity, surrounded by an incomplete or asymmetric myometrial mantle,[4] or as an empty uterine cavity, with a chorionic sac separated by more than 1 cm from the most lateral edge of the uterine cavity, with a thin myometrial layer surrounding the chorionic sac.[5] Haemodynamically stable women were counselled regarding the different treatment options at the time of diagnosis and offered a choice of treatment. Options included medical management with methotrexate (MTX), a minimally invasive approach with UTCE, or a conventional surgical treatment that included conservative surgical resection. Haemodynamically unstable women underwent emergency surgical intervention.

Ultrasound-guided transcervical forceps extraction (UTCE) is a method very similar to chorionic villus sampling with forceps, previously described by Pons et al.[6] The procedure is different from conventional surgical interventions for treating interstitial pregnancies because the ectopic pregnancy is approached via a natural route, through the vagina, cervical canal and endometrial cavity, without any incision of the skin or uterus. During UTCE, the surgeon removes the gestational sac under transabdominal ultrasonographic guidance (Figure 1).

Figure 1.

Schematic drawing of ultrasound-guided transcervical forceps extraction of an unruptured interstitial pregnancy.

UTCE was performed in an inpatient setting, with the woman being prepared similarly to the preparation for a dilatation and curettage. The woman was placed in the dorsal lithotomy position, and a speculum was inserted into the vagina. The cervix was swabbed with povidone-iodine or a chlorhexidine solution, and the depth and inclination of the uterine cavity were measured using uterine sounding, before insertion of forceps. If required, the cervix was further dilated with Hegar dilators until small forceps (Gross, without ratchet, Solco Biomedical, Pyeungtaek, Korea; Figure 2) could be inserted. Under transabdominal ultrasonographic guidance surveillance, the forceps were moved through the cervical canal toward the fundus and the ectopic gestational sac. The surgeon grasped the gestational sac with the forceps and selectively extracted the gestational sac (see Supplementary material, Video S1); if needed, gentle curettage was also performed. Intravenous nonsteroidal anti-inflammatory drugs were used for pain management.

Figure 2.

The forceps used during ultrasound-guided transcervical forceps extraction of an unruptured interstitial pregnancy.

Serum β-hCG levels were checked on post-procedure day 1. An additional procedure was considered if the decline in serum β-hCG levels was not appropriate (to at least 50% below baseline); suggested procedures included a second UTCE, laparoscopic surgery, or a single systemic dose of MTX (50 mg/m2 of body surface area).

Laparoscopic surgery or multiple systemic doses of MTX (1.0 mg/kg/day followed by leucovorin [0.1 mg/kg/day] on alternate days) were the choices for women who chose not to undergo UTCE.

Results

During the study period, 16 interstitial pregnancies were diagnosed and treated at our institution. Of these, six were treated with UTCE (all performed by a single surgeon), nine were treated with surgical interventions (laparoscopic cornual wedge resection), and one was treated with multiple systemic doses of MTX. The demographic characteristics and risk factors for ectopic pregnancy in the 16 women are summarised in Table 1. There were two heterotopic gestations, with a combination of interstitial and intrauterine pregnancies, in the surgery group; both were treated with laparoscopic wedge resection. After that, both pregnancies were completed by an at-term caesarean delivery.

Table 1. Characteristics of women
 UTCE (n = 6)Operation (n = 9)MTX (n = 1)
  1. Values are given as median [range] or number (percentage).

  2. Correction added on 29 May 2013, after first online publication: the brackets shown in Table 1 were published incorrectly and have now been corrected.

Age, years32 [30–43]33 [25–43]37
Parity0.5 [0–2]1 [0–2]0
Gravidity2 [1–5]3 [1–8]4
History of caesarean section1 (16.7)2 (22)0
History of other uterine surgery1 (16.7)00
History of curettage3 (50)5 (56)3
History of tubal surgery03 (33)0
Assisted reproductive technology3 (50)4 (44)0
Need for emergent surgery02 (22)0
Gestational age at treatment, weeks7.0 [5.4–8.4]6.4 [5.4–7.7]5.7
Pretreatment β-human chorionic gonadotrophin, mIU/ml

33 074

[17 797–69 303]

33 057

[20 319–50 271]

4478

Table 2 shows the clinical outcomes for each treatment method. Major differences were not observed in the most relevant parameters among the three groups. One woman undergoing UTCE required additional treatment because of a sustained elevation of the post-procedural serum β-hCG level. This woman was the first to undergo UTCE at our institution and required an additional UTCE and two doses of MTX. All other women undergoing UTCE were successfully treated in a single session. Three women had subsequent pregnancies after their initial UTCE. Two of the women delivered by caesarean section because of twin pregnancies or a history of myomectomy; the third woman delivered vaginally.

Table 2. Clinical outcomes after each method of treating interstitial pregnancy
 UTCE (n = 6)Operation (n = 9)MTX (n = 1)
  1. Hb, haemoglobin.

  2. Values are given as median [range] or number (percentage).

  3. a

    From the pretreatment haemoglobin concentration to the concentration post-treatment.

  4. Correction added on 23 May 2013, after first online publication: the brackets shown in Table 2 were published incorrectly and have now been corrected.

Success of treatment5 (83.3)9 (100)1 (100)
Need for additional treatment1 (16.7)00
Serious complications000
Pretreatment Hb, g/dl11.9 [11.1–12.9]13.3 [6.8–13.7]13.8
Hb change, g/dl*1.7 [0.3–2.2]1.9 [0.9–3.3]2.9
Duration of admission, days3 [2–8]4.5 [4–7]4
Need for transfusion01 (11.1)0

Discussion

This report demonstrates that UTCE has a high success rate, a low rate of additional required interventions, and a lack of serious complications. One of the benefits of UTCE is that it prevents the excessive bleeding that is common during surgery or local, direct injection of MTX. The rich vascular anastomoses of the uterine and ovarian arteries in the interstitial portion of the fallopian tube enhance the risk of bleeding during more invasive treatments. Uterine scarring can also be prevented by UTCE treatment, making elective caesarean delivery unnecessary for future pregnancies, unlike conventional surgical interventions. If a UTCE treatment fails, other treatment options, including surgical intervention or systemic MTX administration, are possible. Furthermore, inexperienced surgeons can also be readily trained to perform UTCE safely. The UTCE training can be provided during elective dilatation and curettage procedures performed after miscarriages. If physicians have some experience in performing chorionic villus sampling with forceps, they can easily learn UTCE. Unlike MTX treatment, UTCE promotes quick recovery because of its mass removal effect and the absence of complications associated with systemic exposure to MTX. Finally, the benefits associated with the use of UTCE for treating unruptured interstitial pregnancies may be translated to procedures for other ectopic pregnancies, such as caesarean scar pregnancies or cervical pregnancies; investigations are currently ongoing in these areas.

Previously, three trials were conducted with the intention of avoiding uterine incisions during the treatment of interstitial pregnancies through a transcervical approach;[7-9] all three methods required laparoscopic surveillance. Laparoscopic surveillance is certainly less invasive than laparotomy, but is more invasive than the absence of abdominal surgical incisions. UTCE does not require laparoscopic surveillance and does not leave an abdominal scar. One previous trial involved a blunt suction curettage and others have entailed USG-guided suction curettage. Transcervical suction evacuation carries some risk of intrauterine injury as the result of the relatively nontargeted negative pressure of the evacuator; however, UTCE only involves the grasping of the gestational sac with forceps, under ultrasound-guided surveillance, followed by its selective extraction. As a result, UTCE is less likely to cause unexpected uterine injuries than is transcervical suction evacuation. During the procedure, the surgeon does not need to remove the entire gestational sac; disruption of the gestational sac is sufficient to terminate the pregnancy. An attempt to completely remove the gestational sac may cause unintended uterine injury or bleeding.

UTCE is not recommended in women who are haemodynamically unstable because of the need to carefully control bleeding at the rupture site. In addition, UTCE should not be promoted for interstitial pregnancies at more than 10 weeks of postmenstrual age because of the possibility of uterine injury resulting from the developing bony parts of the fetus. The procedure is also safer if it is performed at a referral centre that can attend to emergency conditions, especially if the operator has had limited experience with ultrasound-guided procedures.

This report is limited by its retrospective, single-centre, nonrandomised design, and small study population. A randomised controlled trial is warranted for comparing the objective outcomes of different treatment methods for interstitial pregnancies, including laparoscopic surgery, pharmaceutical intervention and UTCE.

The development and widespread use of high-resolution ultrasonography and rapid, quantitative β-hCG assays have enabled the detection of an interstitial pregnancy before rupture and have made possible the administration of earlier and more conservative treatments. Moreover, real-time ultrasonography allows us to track our actions during therapeutic procedures; therefore, UTCE for interstitial pregnancy was performed safely and successfully. In this report, we have introduced the UTCE technique and reported our experience with the technique compared with conventional treatments. UTCE is recommended as a safe, effective option for treatment of unruptured interstitial pregnancies in this era of minimally invasive surgery.

Conclusion

Ultrasound-guided transcervical forceps extraction (UTCE) is proposed as a minimally invasive, effective and safe option for the treatment of unruptured interstitial pregnancy.

Disclosure of interests

The authors do not have any conflicts of interest to report, nor do they have any financial relationships relevant to this article to disclose.

Contribution to authorship

SJL and HSW designed the procedure. SJL performed the procedure. JWA and SHL collected and analysed the data. JWA and SPK wrote the first draft and coordinated manuscript preparation. All authors approved the final manuscript. SJL is the guarantor.

Details of ethics approval

The institutional review board of Ulsan University Hospital approved this study (12-09).

Funding

None.

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