Closed loop small bowel obstruction due to herniation through silastic ring after bariatric surgery
- 1 Medical Education Unit, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
- 2 Department of General Surgery, St John of God Midland Public and Private Hospitals, Midland, Western Australia, Australia
- Correspondence to Dr Rama Chidambaram; rama_cc@hotmail.com
Abstract
Bariatric surgery is an effective treatment for obesity and obesity-related complications. Weight regain after surgery plagues all methods of bariatric procedures including the minigastric bypass. The use of a ‘silastic ring’ around the gastric pouch has been shown to reduce weight regain. We present here a very rare complication of silastic ring use, in which a loop of small bowel had herniated through the ring and produced a closed loop small bowel obstruction. The patient was successfully treated with an emergency laparotomy to resect the silastic ring and release the herniated bowel. This case highlights the hernia risk that silastic rings pose and cautions careful consideration before their use.
Background
Bariatric surgery is an effective treatment for obesity and obesity-related complications.1 A multitude of procedures now exist and each have their own advantages and disadvantages.2
The minigastric bypass (MGB) also known as the single anastomosis gastric bypass or one anastomosis gastric bypass or omega loop gastric bypass was developed in the 1990s and poses an alternative to the Roux-en-Y gastric bypass (RYGB).3 It involves the creation of a narrow gastric pouch and a loop gastrojejunostomy 150–200 cm from the duodenojejunal flexure, with no enteroenterostomy and consequently with no closure of mesenteric defects and a shorter operative time.4 Complication rates are low and late complications include reflux, gastric and oesophageal ulcers, marginal ulcers, malnutrition and weight regain.3 5
To address weight regain, a recognised modification to both MGB and RYGB is the use of a ‘silastic ring (SR)’ around the gastric pouch to create a ‘banded bypass’.6–9 The SR is placed at the mid-to-distal-third of the gastric pouch and can measure between 6.5 and 8 cm in circumference.6–10 Described SR related complications include erosion, slippage, stenosis and intolerance due to poor quality of eating, regurgitation and vomiting.11–13
Below, we present a case of small bowel herniation through an SR which was placed during previous MGB.
Case presentation
A woman in her 40s presented with a 24-hour history of persistent vomiting and generalised abdominal pain. She had a previous laparoscopic gastric band which had been reversed and converted to an MGB; this procedure was done 12 months prior to her presentation. An SR was inserted at the time to augment her MGB.
Her MGB was uneventful and she had no postoperative complications. Over the last 12 months, she had successfully lost 72 kg and weighed 68 kgs at the time of presentation.
She presented with colicky pain that had progressed to constant pain. She was not obstipated and had a normal bowel movement at the emergency department (ED). Except for a laparoscopic cholecystectomy several years ago, she had no other relevant medical or surgical history. She was a non-smoker and drank alcohol in moderation socially.
On examination, she was noted to be having rigours. Her heart rate was 70 beats per minute, blood pressure was 130/70 mm Hg, respiratory rate was 18 breaths per minute, oxygen saturation was 100% with room air and she was afebrile. She was not distended and had localised guarding at the epigastrium on abdominal palpation.
Investigations
The patient’s full blood count was normal with a haemoglobin count of 140 g/L and white cell count of 7.1 with a normal differential count. Her renal function was normal with a creatinine of 48 µmol/L and eGFR >90. Liver function tests were also normal with a bilirubin of 24 mmol/L and an albumin of 36 g/L. C reactive protein was 1. Urine beta HCG testing was negative and urinalysis was positive for ketones only.
She proceeded to urgent portal venous phase CT of the abdomen and pelvis which showed a dilated loop of small bowel in the left upper quadrant that appeared oedematous and with diminished enhancement. Two transition points were suspected.
Differential diagnosis
The history, examination and investigations were consistent with a closed loop small bowel obstruction. The aetiology was suspected to be due to an internal hernia or due to intra-abdominal adhesions from previous intra-abdominal surgery.
Though her vitals were within normal limits and her blood tests unremarkable, the CT findings were concerning for early ischaemic changes in the closed loop of small bowel.
Treatment
Fluid resuscitation and broad-spectrum prophylactic intravenous antibiotics were commenced in the ED.
The patient then promptly proceeded to an emergency laparotomy. An upper midline laparotomy was performed. A non-dilated and congested loop of jejunum distal to the gastroenterostomy was seen herniating cranially through the SR (figure 1). The SR and its pseudocapsule were resected without complication and the loop of jejunum released. The rest of the abdomen was explored and no other pathologies were noted. The released bowel was deemed viable and no bowel was resected and the laparotomy closed.
(A) Diagram depicting anatomy of minigastric bypass with the use of a silastic ring and the pathological herniation of small bowel through this silastic ring. Hand-drawn diagram contributed by author SP. (B) Intraoperative photograph of oedematous and hyperaemic small bowel and associated mesentery herniating through blue silastic ring. GOJ, gastro-oesophageal junction; SBO, small bowel obstruction.
Outcome and follow-up
The patient started eating a normal diet on the first day postsurgery without complication. She was discharged on the fourth day postsurgery, after her pain was controllable with oral analgesia and her bowels had moved.
At outpatient follow-up, 4 weeks after surgery, the patient was well. Her wound had healed, she was tolerating a normal diet and her bowels were functioning normally. In the process of writing this report, she was further followed up at 8 weeks after surgery and continued to remain well, with no postoperative issues noted.
Discussion
Prosthetic devices around the stomach have been used extensively in bariatric surgery.12
These devices have been proposed to induce weight loss by introducing satiety and restriction and they have also been proposed to prevent weight regain by additionally preventing gastric pouch dilatation.6–8 13–15
Various manufactured SRs exist and a 7.5 cm MiniMizer Ring had been used in our patient. During placement, the atraumatic needle of the MiniMizer Ring is introduced behind the gastric pouch through the lesser omentum and closed as per manufacturer instructions and then fixed with two non-absorbable sutures.16
Early in the use of SRs, ring circumferences of 4.5–5 cm were used but these were associated with high rates of removal due to erosion or for being too restrictive.17 18 Studies trialling various ring sizes have shown, larger sizes to be better tolerated, reduce the risk of erosion and to provide equivalent weight loss.11 12 Today, rings of up to 8 cm in circumference are being regularly placed.10
To date, there have only been two reported cases of small bowel herniation through SRs.19 Both were in cases of SRs used in RYGB.19
It is our belief that substantial weight loss and loss of lesser omentum fat may have contributed to a looser than originally intended SR in our patient. The trend towards larger SRs may also have played a role in this pathology.
Though rare, we wish to highlight the internal hernia risk that these SRs pose and advise surgeons and patients to weigh the risks and benefits of using SRs in bariatric surgery carefully.
Learning points
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Small bowel herniation through silastic rings used in bariatric surgery is possible.
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Early identification and removal of the silastic ring can save patients morbidity resulting from ischaemic small bowel.
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Patients and surgeons need to carefully consider the risks and benefits of silastic rings prior to their use.
Ethics statements
Patient consent for publication
Footnotes
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Contributors Both RC and SP were involved equally in conception, data acquisition and analysis. Manuscript was drafted and edited by RC with minor contributions from SP. Figure 2 was hand-drawn by SP and modified digitally by RC.
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Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
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Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
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Competing interests None declared.
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Provenance and peer review Not commissioned; externally peer reviewed.
- © BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.
References
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