Treatment Injury

Endometrial thermal ablation

In this case study we give an overview of 'Endometrial thermal ablation' and feature expert commentary on how similar injuries might be avoided.

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EVENT: Endometrial thermal ablation
INJURY: Endometrial ablation burns

Case study

Janine, a 37-year-old woman with two children, had suffered from menorrhagia for many years.

Her other medical problems included hypertension and depression, for which she took citalopram. She also took iron tablets. Janine’s menorrhagia had previously been treated with a Mirena® Intrauterine System, as well as oral contraceptives. These had not been fully effective, so Janine and her gynaecologist agreed to surgical treatment in the form of endometrial thermal ablation.

Janine had a thermal ablation and post-operatively was in a lot of pain. This continued to worsen over the following two days and she developed abdominal distension. A computerised tomography (CT) scan was performed, which showed a full-thickness endometrial burn, as well as burns to the sigmoid colon and rectum. Janine was taken to theatre for a washout and was treated with intravenous antibiotics. She fortunately improved and was discharged.

Some days later Janine came to hospital after developing worsening abdominal pain. She had been passing flatus and blood vaginally, and had some rectal bleeding. Janine was taken to theatre where a necrotic cavity was found between her uterus and rectum. An en-bloc hysterectomy and bowel resection with anastomosis was performed, leaving Janine with an ileostomy.

Following this procedure Janine became septic and needed intensive care. A peripherally inserted central catheter (PICC) line was inserted for antibiotics and parenteral nutrition. She made a slow recovery and was discharged three weeks later with ongoing support at home.

A treatment injury claim was made for Janine’s rectal and uterine burns with necrosis leading to rectal resection and ileostomy, hysterectomy and sepsis. ACC accepted the claim as the complications were due to the failure of the equipment used during the thermal endometrial ablation treatment. ACC was able to assist with the costs of Janine’s treatment for the injuries and provide support at home while she was recovering and extra time off work.

Expert commentary:

Sylvia Rosevear, obstetrician and gynaecologist
This case illustrates the very severe consequences for a patient who has consented to a minimally invasive procedure – the effects of which are usually assessed in terms of the primary outcome measures of amenorrhea, heavy bleeding, patient satisfaction (generally 80%) and hysterectomy rates. The management of this case involved not only the local complications, but also the severe intra-abdominal complications relating to the bowel burn. The patient required multidisciplinary treatment. Thermal bowel injury is the most commonly reported life-threatening injury (86% due to radiofrequency endometrial ablation and 5% due to thermal balloon); 80% of the injured required bowel resection. Creating a false passage is a risk with ablation that potentiates thermal damage.

Endometrial ablation is done by second-generation devices in order to minimise the risk of severe injury and the technical difficulties of the procedure (related to hysteroscopic techniques), and to give a more uniform clinical result.1, 2 It is simpler to perform, has a shorter operating time and can be done under local anaesthetic. This particular case used MenoTreat™, which is now not available in New Zealand. The severe complication was a problem of probable endometrial cavity perforation. In order to cause the bowel burns, perforation was likely to have occurred as more fluid added with the pressure drop outside the uterus.

Additional adverse events from endometrial ablation include pelvic cramping (from prostaglandin release), nausea and vomiting, rupture of the uterus, infection, post-ablation tubal sterilisation syndrome and haematometra.

There are three second-generation devices generally available in New Zealand. Two are balloon-type devices – Thermachoice™ (Johnson & Johnson), Thermablate EAS™ (Idoman) and Nova Sure®, which is radio frequency ablation. Thermachoice™ is a water-based system that takes longer. Thermablate™ uses glycerine, which is heated to 173 degrees outside the uterus. It only allows a maximum 28ml of fluid – on average 4-12ml to pressurise an average-size uterus – and the machine controls the fluid volume and pressure. A larger uterus can be treated with Thermablate™, which takes two minutes and six seconds. Nova Sure® (Hologic) uses bipolar radiofrequency electrical energy to ablate, and has a higher amenorrhea rate. It can only ablate an endometrial cavity measuring 8-10cm. Nova Sure™ checks endometrial cavity integrity with carbon dioxide into the cavity. It is a proactive test of endometrial integrity before starting the procedure, whereas balloon methods alarm if the pressure goes down. It will detect a perforation equivalent to an 18-gauge needle. It vaporises the endometrium down to the myometrium. The results therefore are not affected by endometrial thickness. It ablates 5-7mm in the fundus and 2-3mm at each cornua. It draws the endometrial cavity down onto the device. Microsulis™ (microwave ablation) is now not available in New Zealand.

Consent should be clear and some reference made to the instrument being used and potential risks.3 The MAUDE (Manufacturer and User Facility Device Experience) database is a source of updated information on complications of devices. It includes medical device reports submitted to the United States Food and Drug Administration by mandatory reporters (manufacturers, importers and device user facilities) and voluntary reporters such as health care professionals, patients and consumers. In general, complication rates can be up to three times what might be stated by a company.

Key points:

Contraindications to ablative procedures:

  • Myomectomy (no previous surgery)
  • No intrauterine pathology e.g. fibroids
  • No previous pelvic inflammatory disease/abdominal surgery
  • Classical caesarean section
  • Previous endometrial ablation
  • Myometrial thickness of caesarean section scar less than 8-10mm
  • Uterine cavity less than 4cm
  • Uterine length (cervix to fundus) no more than 12cm
  • Abnormal uterine shape

Consider cervical softening agents if dilatation is anticipated to be difficult
Abandon procedure if any concern about possibility of perforation of the uterus
Inform patient to expect rapid to normal recovery post-procedure, and ask them to seek treatment if they deteriorate – ensuring that adverse events related to the device can be notified to regulatory authorities.5

References/Websites:

  1. Daniels J.P., Middleton L.J., Champaneria R., Khan K.S., Cooper K., Mol, B.W.J., Bhattacharya S., on behalf of the International Heavy Menstrual Bleeding IPD Meta-analysis Collaborative Group. Second generation endometrial ablation techniques for heavy menstrual bleeding: network meta-analysis. BMJ 2012;344:e2564 doi:10.1136/bmj.e2564 (published 23 April 2012).
  2. The Cochrane Collaboration, The Cochrane Library, 2013, Issue 8. Endometrial resection and ablation techniques for heavy menstrual bleeding (Review). Lethaby A., Penninx J., Hickey M., Garry R., Marjoribanks J.
  3. Brown J., Blank K. Minimally invasive endometrial ablation device complications and use outside of the manufacturer’s instructions. Obstetrics and Gynecology 2012: 120 (4) 865-870.
  4. Guidance on the responsibilities of manufacturers, the regulator and clinicians with respect to endometrial ablation. The recommendations of a joint workshop February 2011. Medicines and Healthcare Products Regulatory Agency. RCOG. British Society for Gynaecological Endoscopy.
  5. To report incidents: www.medsafe.govt.nz/regulatory/devicesnew/9adverseevent.asp

Claims information:

Between July 2005 and March 2014 ACC received 3174 claims relating to the gynaecology treatment context. Of these, 70% were accepted and 30% were declined. Of the 3174 decided claims 18 were ablation-related injuries, of which 14 were accepted and four were declined.

The most common reason for declining a claim was no injury identified or that there was no causal link between the treatment provided and the injury claimed.

Downloads

April 2014 treatment injury case study – Endometrial thermal ablation

June 2014 Newsletter

Published 06/06/2014

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