Use real-time near-infrared fluorescence during Heller’s cardiomyotomy for achalasia cardia

Abstract

Laparoscopic Heller’s cardiomyotomy is the surgical procedure of choice in the management of oesophageal achalasia. It is critical to confirm the completeness of the myotomy and mucosal integrity at the conclusion of the procedure. This is conventionally achieved by intraoperative endoscopy and dynamic air leak test. Other modalities that can be used to confirm the myotomy and the integrity of the mucosa at the myotomy site are oesophageal manometry and a methylene blue dye study, respectively. Indocyanine green (ICG) has been in clinical use for more than six decades. The real-time integration of ICG fluorescence with laparoscopy is a relatively new breakthrough. Here, we present a novel method of using real-time near-infrared ICG fluorescence for confirming the completeness of the myotomy and mucosal integrity at the myotomy site post laparoscopic Heller’s myotomy. This is the first report on the use of ICG in laparoscopic Heller’s cardiomyotomy that we are aware of.

INTRODUCTION

Laparoscopic Heller’s cardiomyotomy is the surgical procedure of choice in the management of oesophageal achalasia. The incidence of intraoperative oesophageal perforation is 0%–6% and 7.8%–28% in patients who undergo the procedure as the primary treatment of achalasia and in those after failed endoscopic therapy (either balloon dilation or botulinum toxin injection), respectively.[1] In addition, incomplete myotomy is associated with a recurrence of symptoms. It is responsible for wmore than 90% of surgical failures and accounts for morwe than half of all revisional surgeries.[2] Therefore, it is critical to confirm the completeness of the myotomy and mucosal integrity at the conclusion of the procedure. This is conventionally achieved by intraoperative endoscopy and dynamic air leak test.[3,4] Other modalities that can be used to confirm the myotomy and the integrity of the mucosa at the myotomy site are oesophageal manometry and a methylene blue dye study, respectively. Indocyanine green (ICG) has been in clinical use for more than six decades. Recently, the utility of ICG for endpoint marking in peroral endoscopic myotomy was demonstrated by Kurumi et al.[5] Here, we present a novel method of using real-time near-infrared ICG fluorescence to confirm the completeness of the myotomy and mucosal integrity at the myotomy site post laparoscopic Heller’s myotomy.

The real-time integration of ICG fluorescence with laparoscopy is a relatively new breakthrough. The use of ICG has been reported for foregut procedures, such as sleeve gastrectomy, to validate the perfusion of the gastric sleeve and in surgery for stomach cancers to identify lymph node dissemination.[6,7] This is the first report on the use of ICG in laparoscopic Heller’s cardiomyotomy that we are aware of.

TECHNIQUE

The VironX system with the VironX near-infrared light (NIR) (Maxer Endoscopy GmbH, Germany) was used for fluorescence-guided surgery. In real time, the fluorescence image was supplemented with a white light image.

After the intended myotomy was completed in patients with oesophageal achalasia undergoing laparoscopic Heller’s cardiomyotomy, the stomach distal to the myotomy site was clamped by twisting the umbilical tape that encircles the proximal stomach. Ten milligrams of ICG diluted in 50 mL of saline was instilled intraluminally through the nasogastric tube, with the tip positioned at the myotomy site. On switching to NIR mode, near-infrared fluorescence (NIRF) becomes evident at the myotomy site. The completion of the myotomy was confirmed by the uniform fluorescence seen throughout the myotomy. The contained intraluminal fluorescence confirmed the mucosal integrity [Figure 1]. After the successful completion of the test, ICG was allowed to pass freely into the intestines since it has little affinity for the mucosa of the intestine.

Figure 1.

Real-time near-infrared fluorescence assessment of the myotomy site. Image on the top left shows the laparoscopic view of bulged out mucosa at the cardiomyotomy site, image on the bottom left shows the infrared view of ICG fluorescence and the augmented image is seen in real time on the right side of the panel. Image shows contained fluorescence at the myotomy site confirming the mucosal integrity. ICG: Indocyanine green

We used this approach in four patients undergoing a laparoscopic Heller’s cardiomyotomy and fundoplication (Toupet, n = 3; Dor, n = 1) after informed consent. The completeness of the myotomy was confirmed by uniform fluorescence. There was no evidence of a leak in any of the patients, which was corroborated by the intraoperative air leak test and upper gastrointestinal endoscopy. There were no post-operative complications for any of the four patients.

BENEFITS

When it comes to validating mucosal integrity at the myotomy site, ICG has a number of advantages. First, it is simple to use and does not discolour the oral cavity, which is seen with the use of methylene blue. Second, unlike methylene blue, it does not discolour the urine. Third, the test is repeatable and can accurately pinpoint the area of the leak. In the event of a leak, it does not stain the mucosa and surrounding structures, enabling easy identification and suturing of the mucosal perforation. Fourth, it does not hinder any further endoscopy that may be required.

In the absence of adequate distal occlusion, ICG flows down into the stomach and it is not retained in the area of interest since it does not bind to the mucosa. This could lead to poor visualisation and a false-negative test. Furthermore, surgical groups performing a Dor fundoplication as the preferred procedure avoid dissecting the posterior window. In such scenarios, an encircling tape is not available for adequate distal clamping. This difficulty could be overcome by mixing the ICG solution with the human albumin. This leads to the adsorption of ICG. The mixing of solutions leads to the adsorption of ICG to human albumin, which increases the hydrodynamic diameter, resulting in the increased intensity of fluorescence.[8] As an alternative to human albumin, we used egg white in one of our patients who underwent Dor fundoplication [Figure 2]. This is locally available and is cost-effective. However, the dose, concentration and time of instillation to obtain adequate fluorescence are still not clear.

Figure 2.

Real-time composite image at the completion of the Dor fundoplication. Image on the top left shows the infrared view of ICG fluorescence, image on the right side is the white light traditional laparoscopic view of the bulging mucosa at the lower end of the oesophagus (arrowhead) with separated muscle layers (short arrows), along with a completed Dor fundoplication (long arrow) and image on the bottom left is the real-time augmented image which shows contained uniform fluorescence suggestive of complete myotomy with maintained mucosal integrity. ICG: Indocyanine green

CONCLUSION

Real-time NIRF following intraluminal instillation of ICG is a straightforward, safe and reliable way to assess the cardiomyotomy site. Larger prospective studies are required to validate this technique.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.