Management of post-traumatic ischaemic ileal stricture using intraoperative indocyanine green fluorescence-guided resection

Abstract

Blunt abdominal trauma can affect mesenteric circulation which may lead to bowel strictures. Indocyanine green (ICG) angiography can be used to assess mesenteric blood flow and bowel perfusion as a guide to resect length intraoperatively. But this concept has not been applied to ischaemic bowel strictures. We present a case of ischaemic ileal stricture induced by blunt abdominal trauma which was managed by resection and anastomosis. Intraoperative near-infrared (NIR) ICG angiography was used as a guide to resect the bowel length. This case emphasises that ischaemic bowel strictures should be suspected in patients presenting with intestinal obstruction following trauma. Resection and anastomosis of the affected segment remains the primary treatment modality with excellent outcomes. NIR ICG angiography is a real-time objective and useful resource for assessing bowel perfusion and could be used to determine the length of the segment to be resected in patients with ischaemic bowel stricture.

Background

Blunt trauma to the abdomen is common but difficult to recognise. The small bowel is the third most commonly involved organ in such cases after liver and spleen. Most of the cases are due to seatbelt or handlebar injuries in road traffic accidents.¹ The majority of such cases are managed non-operatively. Significant trauma can affect mesenteric circulation leading rarely to bowel strictures. Indocyanine green (ICG) angiography is commonly used to assess bowel perfusion as a guide to resect length intraoperatively.² To the best of our knowledge, this concept has not been applied to ischaemic bowel strictures. Here, we present a case of ischaemic ileal stricture induced by blunt abdominal trauma which was managed by intraoperative near-infrared (NIR) ICG fluorescence angiography guided resection and anastomosis. Informed written consent to publish this case report and images was obtained from the patient.

Case presentation

A man aged 28 years presented with a colicky pain abdomen and abdominal distention 4 days following blunt abdominal trauma due to bike handle injury. X-ray abdomen erect showed multiple air fluid levels. Ultrasound abdomen revealed circumferentially thickened ileal bowel loops with fat stranding. Diagnosis of subacute intestinal obstruction was made. He was advised admission and did not get admitted as he was lost to follow-up. After 3 months, he presented to our hospital with similar complaints. On the examination, a firm vague lump was palpable in the right iliac fossa with tenderness over that area.

Investigations

CT enterography revealed a circumferential long segment wall thickening causing lumen narrowing, 10 cm proximal to the ileocecal junction (ICJ) with proximal dilatation and increased mesenteric vascularity (figure 1A). On CT angiography, the ileal branch of the superior mesenteric artery supplying the narrowed ileal segment was cut-off (figure 1B). In view of temporal relationship to trauma, stricture due to mesenteric vascular injury was considered and surgical resection and anastomosis was planned.

Figure 1.

(A) CT enterography. A circumferential long segment ileal wall thickening present. (B) CT angiography. The ileal branch of the superior mesenteric artery supplying the narrowed ileal segment appears cut-off (arrow).

Treatment

A midline laparotomy incision was made. A thickened ileal segment was present 10 cm proximal to ICJ approximately 10 cm in length. The corresponding mesentery appeared grossly fibrosed, pointing towards sequelae of prior injury. An intraoperative NIR-ICG fluorescence angiography was performed for confirming the impaired perfusion and as a guide for the length of the segment to be resected. For this, 25 mg of ICG diluted with distilled water to a concentration of 2.5 mg/mL was injected into an antecubital vein. The SPY Elite imaging device (LifeCell, New Jersey, USA) was used for intraoperative imaging up to 5 min after the dye injection. There was decreased perfusion in the thickened strictured segment and 2 cm proximal to it. He had abdominal pain which was out of proportion to the luminal narrowing. Intraoperative finding of decreased bowel perfusion of 2 cm proximal apparently normal looking bowel could have been a contributing factor to this pain. Therefore, this segment was also resected and a stapled isoperistaltic side to side anastomosis was performed (figure 2A, B).

Figure 2.

(A) Indocyanine green fluorescence angiography showing non-perfused ileal segment (white arrows). (B) Resected thickened and fibrosed specimen of the same ileal segment including 2 cm of normal looking bowel (black arrow).

Outcome and follow-up

The patient was started orally on postoperative day (POD) 2 and discharged on POD 5. Histopathology of the resected specimen revealed extensive ulceration of the mucosa with acute fibrinous inflammatory exudate over a length of 9 cm. Some of the mesenteric vessels showed fibrointimal proliferation and partial occlusion of the lumen. The symptoms resolved completely after surgery and patient is doing great 6 months postsurgery.

Discussion

Trauma-induced ischaemic bowel strictures are uncommon. Most patients with bowel trauma get operated for acute abdomen due to bowel perforation or bleeding. However, in a subset of patients, direct or indirect ischaemic bowel injury due to trauma gets unnoticed and these patients later can clinically present with intestinal obstruction. Steatorrhoea and weight loss may also be seen. Rarely transmural progressive ischaemia may also lead to delayed bowel perforation.^{3 4}

The diagnosis of post-traumatic ischaemic bowel strictures is favoured when a patient presents with obstructive intestinal symptoms with the presence of bowel stricture on radiological imaging along with the history of significant blunt abdominal trauma without any prior gastrointestinal disease. CT features of ischaemic bowel strictures may resemble other bowel pathologies such as Crohn’s disease, radiation enteritis, non-steroidal anti-inflammatory drug induced enteropathy and cryptogenic multifocal ulcerous stenosing enteritis.⁵ Thus, the history of previous abdominal symptoms, exposure to radiation, prolonged drug intake and temporal relationship to trauma are important in such cases. Hara et al⁶ recently reviewed 62 cases of small bowel stenosis following trauma and reported that 64% of patients presented with symptoms within 1 month and only 9% after 2 months. However, the presentation can be delayed even for years.⁷ The site of stenosis was within 100 cm of the ICJ in 87% of cases in this review. Lublin et al⁸ reviewed 15 cases of colonic stenosis following blunt trauma to abdomen where the median time of presentation was 20 weeks and most of them occurred in sigmoid colon.

The length of the strictured segment varied from 2 to 15 cm (mean=7.4 cm) in one study with eight patients with postischaemic bowel strictures.⁵ The ileum and the jejunum are the most commonly involved sites in the small bowel as they are relatively fixed and anchored to retroperitoneum.⁹ Yair et al¹⁰ studied 266 patients of blunt abdominal trauma and found that terminal ileum and proximal jejunum were involved in 59% and 23% cases, respectively. Sigmoid colon may be involved preferentially in some cases due to its mobility. This can lead to impingement of this part against the spine causing injury due to seatbelt.⁸ Alcohol or drug intoxication causes relaxation of abdominal wall muscles increasing the susceptibility to crush injuries.¹¹ This might be the reason for higher incidence of post-traumatic ischaemic bowel strictures in young adult males.

In histopathology, this entity shows features of ischaemic enteritis or ischaemic colitis due to other causes. Fibrosis and inflammatory exudate are seen in most cases which can extend up to submucosa in partial thickness injuries or can extend transmurally. Mucosal ulceration may also be seen¹² as in our case. Bala et al¹³ suggest that histology can help differentiate between Crohn’s disease and ischaemic strictures since lymphoid aggregates are seen in Crohn’s disease whereas acute inflammatory cells are seen in ischaemia.

ICG is a water soluble dye that binds to plasma proteins (low and high density lipoproteins) and absorbs light in the infrared spectrum at 800 nm and emits fluorescence at 830 nm. This property can be used to assess tissue microperfusion using an infrared emitting light source.¹⁴ The dose of ICG used for fluorescence imaging is heavily dependent on the tissue whose perfusion is to be studied. The maximum safe dose indicated for in vitro use is considered to be 2 mg/kg.¹⁵ The dose of ICG for gastrointestinal perfusion assessment is highly variable (ranging from 5 mg to 25 mg)^16–18 and has not been standardised due to the lack of sufficient data. Some authors have previously used a 25 mg dose for gastrointestinal perfusion assessment while injecting the dye in the antecubital vein with the SPY imaging device.¹⁹

The concept of ICG angiography in bowel surgeries has been applied in intraoperative vascular perfusion assessment in small and large bowel anastomosis to decrease leak rates,²⁰ to precisely localise bowel bleed²¹ and tumours,²² to identify ureters and to facilitate vascular dissection in colorectal resection.²³ There was a change in resection site in colorectal cancer surgeries in 34.5% of cases with a median resection difference of 2 cm when using ICG angiography in a study of 110 patients.¹⁴ In an emergency setting, ICG fluorescence imaging has been used to define limits of resection in cases of acute mesenteric ischaemia,¹⁸ strangulated/obstructed hernias,¹⁶ perforations and diverticulitis.²⁴ In a retrospective review by Liot et al,²⁴ this technique altered intraoperative decisions in one-third of their patients and none of their patients had a relook surgery for ischaemia. This technique is feasible in emergency bowel surgeries as it is a quick and easy to use resource. It has even been proposed to be considered as an Enhanced Recovery after Surgery (ERAS) item in colorectal surgeries.²⁵

To our knowledge, however, this technique has not been used previously as a guide for the length of the bowel to be resected in ischaemic bowel strictures. Since ICG angiography can assess mesenteric blood flow, it can serve as a useful guide in situations such as this, where there could be a dilemma in the length of resection. In addition, this technique could be used for more than once in the same patient in the same sitting as the dye gets washed out quickly unless venous congestion is present.

However, the intensity of the fluorescence was not quantified and the assessment of perfusion is largely operator dependent. In addition, the optimal dose of ICG for gastrointestinal perfusion assessment is not known. Controversy exists on whether to use relative (due to high interhuman variability) or absolute method (to account for variables such as haemoglobin concentration, oxygen saturation, etc) of quantifying perfusion using this technique.¹¹ Thus more studies are needed to set cut-off values for perfusion before this can be applied routinely in such scenarios. This case, though, provides an insight on how this affordable, useful and quick technique could be used in varied surgical situations in bowel surgeries and elsewhere.

Learning points.

• The diagnosis of post-traumatic ischaemic small bowel stricture is difficult and is often missed due to the subtle nature of symptoms. We must have a high index of suspicion in patients presenting with abdominal pain/intestinal obstruction following trauma.

• Resection and anastomosis of the affected segment remains the primary treatment modality with excellent outcomes.

• Intraoperative indocyanine green fluorescence angiography is a real-time objective and useful resource for assessing bowel perfusion and could be used as a point of care technique to determine the length of the segment to be resected in ischaemic bowel strictures.

Ethics statements

Patient consent for publication

Obtained.