Uterine dehiscence in a nullipara, diagnosed by MRI, following use of unipolar electrocautery during laparoscopic myomectomy: Case report

Uwe Hasbargen1,4, Margarita Summerer-Moustaki1, Peter Hillemanns1, Jürgen Scheidler2, Rainer Kimmig3 and Hermann Hepp1

1 Departments of Obstetrics and Gynaecology and 2 Diagnostic Radiology, Klinikum der Universität München, Grosshadern, Marchioninistr. 15, D-81377 Munich and 3 Department of Obstetrics and Gynaecology Universitätsklinikum Essen, Essen, Germany


    Abstract
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 Abstract
 Introduction
 Case report
 Discussion
 References
 
Uterine scar dehiscence following laparoscopic myomectomy (LM) is a rare event. We present a case of an magnetic resonance imaging-diagnosed uterine dehiscence in a primigravid patient at 29 weeks gestation, following a laparoscopic subserosal myomectomy, performed using unipolar electrocoagulation. Pregnant patients with a history of prior surgery where unipolar electrocoagulation is used on the uterus should be closely followed throughout pregnancy and uterine dehiscence or rupture should be part of the differential diagnosis when they present with abdominal pain.

Key words: laparoscopic myomectomy/MRI/pregnancy/uterine dehiscence


    Introduction
 Top
 Abstract
 Introduction
 Case report
 Discussion
 References
 
Uterine dehiscence, defined as an asymptomatic thinning or separation of a prior uterine scar, is found incidentally in <2% of prior Caesarean section patients (Gabbe, 1996Go). The uterine separation, unlike in the case of uterine rupture, does not involve the uterine serosa or fetal membranes and is not associated with intra-abdominal haemorrhage. In addition to Caesarean section, prior laparoscopic myomectomy (LM) has also been associated with an increased risk of uterine dehiscence and rupture (Dubuisson et al., 2000Go). With the increasing number of patients undergoing LM, there is a concern for increasing rates of subsequent pregnancy uterine dehiscence and rupture, secondary to the questionable integrity of the laparoscopically created and repaired uterine scar, and the uterine damage resulting from the use of electrocautery. We present a patient with prior laparoscopic removal of two subserosal posterior wall fibroids, via use of unipolar electrocautery, whose scar dehisced at 29 weeks gestation. Magnetic resonance imaging (MRI) showed the posterior uterine wall defect, thus making the clinically difficult diagnosis of uterine dehiscence preoperatively possible.


    Case report
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 Abstract
 Introduction
 Case report
 Discussion
 References
 
A 30-year-old primigravid patient was admitted with lower abdominal pain at 29 weeks gestation. Eleven months earlier the patient had undergone a laparoscopy for evaluation of primary infertility at an outlying private clinic. Mild endometriosis was diagnosed and several small peritoneal foci, including one at the posterior uterine wall, were coagulated using unipolar cautery (Valleylab, Tyco Healthcare Group, Boulder, Colorado, USA). Two small pedunculated subserosal myomas measuring 0.7x1.2 cm were also removed near the patient's posterior left uterosacral ligament. Removal of the myomas and haemostasis at the myomectomy sites were achieved with electrocautery. No suturing was required. The patient conceived spontaneously and the pregnancy was uneventful until admission. The patient had no history of other gynaecological or abdominal operations or chronic inflammatory bowel disease.

On admission to the hospital, she was in no acute distress and had normal vital signs, including blood pressure 110/70 mmHg, pulse rate 70/min and temperature 36.1°C. All laboratory results, including complete blood count and electrolytes, were within the normal range. Abdominal exam revealed a soft, normoactive abdomen with uterine tenderness only at time of uterine contractions. Pelvic examination revealed a nulliparous cervix with no vaginal bleeding or premature rupture of membranes. Rectal exam was mildly uncomfortable without a distinct focus of pain. The patient denied any associated symptoms. Sonography showed a vital intrauterine single fetus with normal biometry and normal amniotic fluid. Fetal heart tracing was reactive, without evidence of decelerations. Appendicitis was considered, but clinically excluded by our surgical colleagues who also examined the patient. Premature contractions were treated with 1 µg/min Fenoterol (ß-sympathomimetic) (Partusisten®; Boehringer Ingelheim Pharma, Ingelheim, Germany) and the patient's condition improved, with eventual resolution of her abdominal pain. Fetal lung maturity was induced by 2x12 mg Betamethasone (Celestan®; Essex Pharma, Munich, Germany).

The patient remained clinically stable over the next 72 h, with the exception of a continuous rise in C-reactive protein from <0.5 to 3.8 mg/dl, and a drop in haemoglobin from 12.5 to 9.8 g/dl. At this time she complained of increasing constant abdominal pain and was found to have a low-grade temperature of 38.0°C. Pelvic and abdominal examinations were unrevealing as to the source of the pain or increased temperature. Abdominal sonography was normal, without evidence of free fluid in the abdomen. An amniocentesis to rule out chorioamnionitis produced clear amniotic fluid and an immediate Gram stain and consecutive microbiological testing were negative for intrauterine infection. Following genital cultures, the patient was started on Augmentin (Augmentan®; SmithKline Beecham Pharma, Munich, Germany) for Group B prophylaxis secondary to fetal prematurity. MRI of the abdomen was performed to detect a retro-uterine process not accessible with ultrasonography (such as a retrocaecal appendix or a psoas abscess). A defect in the posterior uterine wall with protruding amniotic membranes was imaged (Figure 1Go).



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Figure 1. MRI findings. Transversal STIR image (TR/TE/TI 5000/90/150 ms) revealing the defect in the uterine wall (arrows). Note the protruding amniotic membranes covered by a thin serosal layer.

 
Immediate Caesarean section lead to the delivery of a live premature female infant, weighing 1270 g and 39 cm long, with Apgars of 8 and 9. The umbilical artery pH was 7.32. At the posterior uterine wall, a 4x7 cm non-bleeding defect with scar-like walls at the site of the patient's prior myomectomy was observed (Figure 2Go). No intra-abdominal haemorrhage was detected and fetal membranes were intact. The posterior uterine defect was closed in two layers. The mother's post-partum course was uneventful. The baby girl required assisted ventilation for 4 days, thrived well after extubation and was discharged from the nursery at the age of 6 weeks (equivalent of 35 gestational weeks) weighing 1960 g and measuring 42 cm.



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Figure 2. Cranio-caudal view of the posterior uterine wall defect. Scarlike defect with non-bleeding edges.

 

    Discussion
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 Abstract
 Introduction
 Case report
 Discussion
 References
 
Uterine dehiscence and rupture are both rare obstetric events, carrying with them a potentially high maternal and infant morbidity and mortality. Theoretically, any prior uterine insult, spanning from uterine perforation during curettage to myomectomy (laparoscopic or via laparotomy) or Caesarean section, can lead to a uterine wall weakness and an increased risk for uterine rupture in a subsequent pregnancy. In Dubuisson's study, with the largest series of pregnancies following LM, the rate of uterine rupture attributed to LM was 1% (Dubuisson et al., 2000Go).

Various authors (Harris, 1992Go; Van De Putte et al., 1999Go) have questioned at LM, the integrity of both laparoscopic incision-making and quality of uterine repair and have recognized the damaging effects of electrocautery. Although Fauconnier highlights the advantage of less adhesion formation following LM (Fauconnier et al., 2000Go), myomectomies performed at the posterior uterine wall, and with the use of electrocautery, led to increased risk of adhesion formation, independent of myoma size. In addition to more adhesions, the inflammation and necrosis associated with electrocautery may lead to delayed healing and a weaker uterine scar, predisposing women in a subsequent pregnancy to an increased risk of uterine scar dehiscence or rupture. This risk was previously thought to be dependent on the size and depth of the removed myoma, with intramural myomas or myomectomies resulting in entry into the endometrium requiring a laparoscopically more difficult to perform two layer closure, thus resulting in weaker scars. Our patient, however, experienced uterine dehiscence following laparoscopic removal of a pedunculated, subserosal, posterior uterine wall myoma, where no actual uterine incision was performed. Pelosi reports a similar case leading to uterine rupture (Pelosi, 1997Go) and Vilos presents four patients, three of which experienced uterine rupture following uterine myolysis, using mono or bipolar electrocautery (Vilos et al., 1998Go). In the discussion portion of Sweeten's paper (Sweeten et al., 1995Go), Dr Russell presents two patients with uterine rupture, the first following unipolar cautery touch-up of a posterior uterine perforation during elective abortion, and the second following excision of a pedunculated fibroid where haemostasis was achieved using unipolar cautery. Therefore, even cases where the uterine muscle is not incised, but in which electrocautery is used, can lead to weakness of the uterus, predisposing to uterine rupture in a subsequent pregnancy. In our case, the electrocoagulation at the myomectomy and endometriosis sites is more likely to have led to the uterine dehiscence, rather than the actual removal of the pedunculated fibroids.

In a prospective study Rozenberg showed a direct correlation between the ultrasound-determined thickness of the lower uterine segment at 37 weeks and the patient's risk for uterine dehiscence or rupture during labour (Rozenberg et al., 1996Go). However, the screening was performed on prior anterior uterine wall Caesarean section scars, all easily visible with ultrasound. For screening purposes of our LM patients, 37 weeks would be too late (since all reported ruptures have occurred earlier) and the scars of posterior myomectomies may not be as easily visible via ultrasound. In our case, MRI was able to depict the posterior uterine wall defect clearly, whereas initial ultrasound evaluation could not. MRI has also been shown to be the most useful imaging modality to evaluate uterine incision healing following Caesarean sections (Dicle et al., 1997Go). We feel that it is also a good modality with which to follow posterior uterine wall scars in pregnant patients with prior LM. As far as the question of fetal safety of MRI imaging is concerned, Baker in his 3 year follow-up study of children imaged in utero with MRI found no increase in the occurrence of disease or disability related to MRI imaging technique (Baker et al., 1994Go).

We recognize the role of LM in the removal of symptomatic, as well as fertility-impeding fibroids in women desiring childbearing. In view of the increased use of LM, we feel that our case alerts operators to the dangers and potential complications associated with the use of unipolar cautery, and that the use of cautery should be avoided in patients desiring subsequent pregnancy. In addition, the presented case should also sensitize obstetricians to carefully review their patients' previous surgical records, and to consider the differential diagnosis of uterine rupture in a patient who presents with the clinical symptoms and past surgical history of our patient. MRI, as depicted in our case, may be the only method for posterior uterine wall scar assessment, and perhaps the only modality making the diagnosis of uterine rupture preoperatively possible.


    Notes
 
4 To whom correspondence should be addressed. E-mail: uwe.hasbargen{at}med.uni-muenchen.de Back


    References
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 Abstract
 Introduction
 Case report
 Discussion
 References
 
Baker, P.N., Johnson, I.R., Harvey, P.R., Gowland, P.A. and Mansfield, P. (1994) A three-year follow-up of children imaged in utero with echo-planar magnetic resonance. Am. J. Obstet. Gynecol., 170, 32–33.[ISI][Medline]

Dicle, O., Kucukler, C., Pirnar, T., Erata, Y. and Posaci, C. (1997) Magnetic resonance imaging evaluation of incision healing after cesarean sections. Eur. Radiol., 7, 31–34.[ISI][Medline]

Dubuisson, J.B., Fauconnier, A., Deffarges, J.V., Norgaard, C., Kreiker, G. and Chapron, C. (2000) Pregnancy outcome and deliveries following laparoscopic myomectomy. Hum. Reprod., 15, 869–873.[Abstract/Free Full Text]

Fauconnier, A., Dubuisson, J.B., Ancel, P.Y. and Chapron, C. (2000) Prognostic factors of reproductive outcome after myomectomy in infertile patients. Hum. Reprod., 15, 1751–1757.[Abstract/Free Full Text]

Gabbe, S.G. (1996) Obstetrics: Normal and Problem Pregnancies. Churchill Livingstone.

Harris, W.J. (1992) Uterine dehiscence following laparoscopic myomectomy. Obstet. Gynecol., 80, 545–546.[Abstract]

Pelosi, M.A. (1997) Spontaneous uterine rupture at thirty-three weeks subsequent to previous superficial laparoscopic myomectomy. Am. J. Obstet. Gynecol., 177, 1547–1549.[ISI][Medline]

Rozenberg, P., Goffinet, F., Philippe, H. J. and Nisand, I. (1996) Ultrasonographic measurement of lower uterine segment to assess risk of defects of scarred uterus. Lancet, 347, 281–284.[ISI][Medline]

Sweeten, K.M., Graves, W.K. and Athanassiou, A. (1995) Spontaneous rupture of the unscarred uterus. Am. J. Obstet. Gynecol., 172, 1851–1855.[ISI][Medline]

Van De Putte, I., Campo, I., Gordts, S. and Brosens, I. (1999) Uterine rupture following laparoscopic resection of rectovaginal endometriosis: a new risk factor? Br. J. Obstet. Gynaecol., 106, 608–609.[ISI][Medline]

Vilos, GA., Daly, L.J. and Tse, B.M. (1998) Pregnancy outcome after laparoscopic electromyolysis. J. Am. Assoc. Gynecol. Laparosc., 5, 289–292.[ISI][Medline]

Submitted on February 7, 2001; resubmitted on March 13, 2002; accepted on May 7, 2002.