Laparoscopic management of cesarean scar ectopic pregnancy
 

Introduction:

Caesarean scar ectopic pregnancy is a rare form of extra-uterine pregnancy.  Although first reported in 1978, when the incidence was a rarity, now the same is constantly rising.  The current reported incidence is between1: 1800 to 2500. 

Pathophysiology: 

Natural history of the condition is not well documented. It has been proposed that the scar surface is increased after many caesarean deliveries, and the anterior uterine wall may be deficient due to fibrosis, poor vascularity and impaired healing. Consequently, the likelihood of implantation into such a scar is increased. However this does not explain caesarean section ectopic pregnancy after one caesarean delivery.

The predisposing factors are as follows:

I.      previous caesarean delivery ( previous uterine surgery ) II.      multiparity

III. advanced maternal age IV.  smoking

Presenting symptoms: 

I.              Amenorrhoea with positive pregnancy test

II.            Vaginal bleeding +/- lower abdominal pain

III.          Usually present between 6 to 17 weeks of pregnancy

Diagnostic Criteria:

Sonographic criteria have been proposed for the diagnosis. 

i.            empty uterine cavity

ii.           empty cervical canal

iii.         presence of gestational sac anteriorly at the level of the internal os iv.             evidence of pregnancy invading into the myometrium

v.            sustained peri-trophoblastic circulation on color Doppler study

vi.          negative sliding organ sign  inability to displace pregnancy with gentle pressure using TVS probe 

Classification of CSEP: Implantation occurs on the uterine scar. The proposed classification although not widely followed are as follows: 

Type 1: This is also called  Endogenic CSEP as gestational sac grows towards uterine cavity, although implanted in the previous scar.                             

Type 2: This is the Exogenic variant of CSEP wherein the gestational sac grows outwards from the previous scar and hence towards the urinary bladder.

Both forms of above classified cesarean scar ectopic pregnancies are diagnosed on transvaginal ultrasound study. The main differential diagnosis is incomplete miscarriage or inevitable miscarriage. Correlation with a good clinical history is hence of vital importance. Features on ultrasound such as GSD, regularity of the sac, presence of a definitive CRL, and demonstration of fetal cardiac activity help plan management. 

Management options: Clinical diagnosis but suspicion based on history is seldom confirmatory. Definitive management is aimed for due to the potential risk of life threatening hemorrhage. Three broad based management options have been documented in literature, which are as follows:

1.     Expectant management with very close monitoring

2.     Pharmocological management

i)                Systemic Methotrexate ii) Local injection of Methotrexate into sac of CSEP iii) Local,injection of embryocides

3.     Surgical management

i)                Dilatation and surgical evacuation ii) Hysteroscopic resection iii) Vaginal excision and resuturing iv) Laparoscopic excision and suturing v) Open excision and suturing vi) Combined laparoscopic and hysteroscopic excision / suturing vii)             Combined laparoscopic and vaginal surgery viii) Hysterectomy

ix) Uterine artery embolisation followed by delayed curettage 

Laparoscopic Management of CSEP: Management of Cesarean scar ectopic pregnancy is discussed here. The advantage  is removal of the conceptus with repair of the defect. The disadvantage is the risk of bleeding especially dealing with gestational tissue with its rich vascularity.  The laparoscopic approach is preferred in skilled hands as it removes the pregnancy and repairs the defect in an attempt to minimise recurrence. This is also done at laparotomy.  However uterine curettage with or without hysteroscopic guidance removes the pregnancy especially in type II CSEP but does not usually have the ease of repair.   Presence of fetal heart activity may have implications  from conscientitious objections from the patient or based on regional regulations 

 At laparoscopy, it is advocated that 10 mls of diluted vasopressin ( 1 unit /ml in 9 mls of normal saline ) is injected at the proposed site of surgery. in addition to vasoconstrictive effects evidenced as blanching there is likely to be aqua dissection.  Transverse incision if required is used with the fesability of removing the gestational sac with endoscopic spatula. A wedge resection involving  the myometrium above and below the gestational sac can also be used. Following removal of the pregnancy, the edges are trimmed and approximated with a single layer of continuous suture using 2-0 polygalactin.  

Literature Search: 

As laparoscopic management is the focus, articles written in English published between January 2010 to December 2018 were included searching online on Medline, PubMed using search terms of cesarean scar pregnancy, cesarean scar ectopic pregnancy, laparoscopic management of cesarean scar pregnancy. Case series and cohort studies were included. Articles  discussed medical and surgical management. Case reports were excluded.

Discussion: Although there is no international concensus in criteria for diagnosis or management there is nonetheless the need for timely management to avoid complications of uterine rupture, hemorrhage, hypovolemic shock and associated morbidity and potential morbidity.  The aim of management of cesarean scar ectopic pregnancy  is to remove the pregnancy, minimise the risk of bleeding and retain the uterus. The modality of treatment discussed needs to be tailored based on  factors such as of hemorrhage, gestational sac size, fetal viability, available expertise. 

The  main stay of pharmacological management is methotrexate. This can be administered systemically. However this requires very close monitoring with planned transvaginal monitoring of the pregnancy and possible serum beta hcg levels. Many clinicians advocate inpatient hospital stay for the same, for surgical management in the event of hemorrhage. 

Hysteroscopic management can be used in CSP type I. This approach has a higher possibility of incomplete removal of the pregnancy. There have been documented reports of pre-operative bilateral uterine artery embolisation.

CSP II, wherein the gestational sac implanted in the lower uterine segment scar and the surrounding myometrium is growing outwards towards the urinary bladder, mandates laparoscopy or laparotomy for removal of pregnancy. As the aim is definitive treatment this results in complete cure, lesser hospital stay and uterine preservation. A wedge resection including the myometrium housing the pregnancy is advocated, after careful dissection of the urinary bladder. Thereafter the uterine wound is repaired to improve integrity of the scar. 

Conclusion: Laparoscopic management  of cesarean scar ectopic pregnancy is an efficient surgical option as this aims to be definitive in excising the pregnancy and repairing the defect. The added advantage is fertility preservation. 

References:

1.               Caesarean scar pregnancy in UK: a national cohort study, HM Harb et al,      BJOG Volume 125, Issue 12, 10.1111/1471-0528.15255, June 2018 

2.               Caesarean scar ectopic pregnancy: Diagnostic challenges and management options,  Pradeep M Jayaram et al, TOG 2017;19:13-20

3.               Minimally invasive therapy for gynaecological symptoms related to a niche in the caesarean scar: a systematic review, LF van der Voet et al, BJOG

10.1111/1471-0528.12537, 

4.               Laparoscopic management of extrauterine pregnancy in caesarean section scar, N. Fuchs et al, BJOG, 10.1111/1471-0528.13060, September 2014

5.               Laparoscopic management of laparoscopy combined with transvaginal management of type 2 cesarean scar prenancy, Huan Ying et al, Journal of Society of Laparoendoscopic Surgeons, June 2013; 17(2):263-272

6.               Operative laparoscopic for unruptured ectopic pregnancy in caesarean scar, Y-L Wang et al, British Journal of Obstetrics and Gynecology, August 2006