Use of indocyanine green-aided real-time angiography in laparoscopic mesenteric cyst excision - A safer approach.

Mesenteric cysts are rare abdominal lesions in the mesentery of the intestine. Complete surgical excision is the only treatment which can be done by an open laparotomy or laparoscopic technique. Application of indocyanine green dye during the surgery helps in identification of the mesenteric vasculature, prevention and early repair of inadvertent iatrogenic vascular and bowel injury.

INTRODUCTION

Mesenteric cysts can occur in the mesentery of the gastrointestinal tract from the duodenum to the rectum, the incidence of which is <1 in 100,000 patients.[1] They are usually found in the mesentery of the small bowel (66%).[2] However, mesentery of the large intestine (33%) may also be involved (usually in the right colon).[2] Usually, these cysts are clinically asymptomatic; however, they can present with non-specific abdominal symptoms such as nausea, vomiting, dull aching pain in the abdomen and bowel disturbances.

With the advent of recent laparoscopic surgical techniques, assessment of the peritoneal cavity and resection of the cyst can be performed successfully without the need for a full laparotomy.[3]

The decision for a surgical approach depends on the size, dimensions and relationships of the cyst with major abdominal structures, as well as the surgeon's degree of experience in minimal access surgery.

Laparoscopic mesenteric cyst excision involves placement of the ports followed by a diagnostic laparoscopy to evaluate the location, vascularity and relations of the cyst. Once identified, the cyst is dissected from its cephalic end and all the vessels in relation with the cyst are coagulated using an ultrasonic energy device.

The cyst is enucleated intact or after aspiration of the contents depending on the size of the cyst. Bowel resection and anastomosis might be required in some cases with bowel adhesions. However, there is always a risk of inadvertent mesenteric vascular injury during the procedure which might jeopardise the bowel perfusion leading to ischaemia of the bowel or leakage of the anastomosis.

OUR MODIFICATION

This report deals with the application of indocyanine green (ICG) dye-based angiography during the laparoscopic excision of primary mesenteric cyst of the sigmoid colon in a middle-aged female patient, who had presented with chronic pain in the left iliac fossa and a palpable lump. A solitary cystic lesion in sigmoid colon mesentery measuring 8 cm × 6 cm was discovered on contrast-enhanced computed tomography of the abdomen.

Technique:

The patient was given an intradermal test dose of 0.1 mg ICG on the ventral aspect of their right forearm a day prior to surgery to rule out any allergic reactions

Three-port laparoscopic cyst excision was planned under general anaesthesia in a steep Trendelenburg position with the left side of the table tilted up

One 12 mm camera port was placed in line with the umbilicus in the right lumbar region [Figure 2]

Figure 2

Placement of laparoscopic ports

Adequate pneumoperitoneum was created by the open technique

Two 5 mm working ports were placed in the right hypochondrium and right iliac fossa, respectively

The mesenteric cyst was identified in the left iliac region, attached to the mesentery of the sigmoid colon and it was mobile

5 mg of ICG dye diluted in 10cc distilled water was injected into the bloodstream intravenously and mesenteric vessels were identified (inflow into arteries for 30 s followed by gradual outflow in veins for 90 s) [Figure 3]

Figure 3

Identifying the mesenteric blood vessels after ICG injection(red and black arrows) and the translucent cyst

Blunt dissection of pericystic adhesions was done. All the blood vessels in relation to the cyst were coagulated with an ultrasonic energy device and the cyst was enucleated from its attachments after confirming the absence of bowel adhesions [Figure 4]. The cyst was transferred to a retrieval bag and it was extracted out intact through the 12 mm port

Figure 4

Completely enucleated mesenteric cyst

5 mg ICG was again injected intravenously to visualise any possible inadvertent vascular or bowel injury. The absence of spillage confirmed the safety [Figure 5].

Figure 5

Indocyanine green fluorescent image of the mesenteric vessels after cyst excision

Contrast-enhanced computed tomography abdomen showing a solitary cystic lesion in relation to the sigmoid colon

Post-operative period was uneventful and the patient was discharged on the 3rd post-operative day. Histopathological examination revealed benign cystic mesothelioma.

BENEFITS

The dye, ICG, can be injected into the human bloodstream with practically no adverse effects.[4]

ICG demonstrates vasculature in deeper tissue planes than those visually apparent, as it operates in the near-infrared (NIR) spectrum in which tissues are more translucent.[4] Light with a wavelength of 750–800 nm, corresponding to the excitation wavelength of the dye, illuminates the tissues.[5] A camera with the required filters can display the NIR fluorescence of dye within tissues. This is performed in real time, allowing the fluorescence data to be superimposed over a standard visual image.

INDOCYANINE GREEN DEFINES THE MESENTERIC VASCULAR ARCADE BEFORE THE EXCISION OF CYST TO PREVENT INADVERTENT VASCULAR INJURY AND TO EVALUATE THE VASCULAR AND BOWEL INJURY AFTER EXCISION OF THE CYST

A minimum duration of 10 min is required for line to ischemic demarcation to be visible to naked eyes. Real-time fluorescence using ICG can detect hypoperfusion early even with macroscopically judged normal perfusion with naked eyes. Thus, apart from the advantage of lesser operative time, a more accurate evaluation of mesenteric blood supply is also made.[6]

This helps in the early diagnosis of mesenteric ischaemia, inadvertent vascular injury and revision of proximal anastomotic line if required.[7] Therefore, evaluation of intraoperative blood flow using ICG angiography is safe and effective for the evaluation of bowel ischaemia during laparoscopic excision of mesenteric cyst.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.