Novel Fluorescence-Guided Gastric Calibration Tube in Robotic Paraesophageal Hernia Repair

Abstract

Background:

Fluorescence-guided (FG) surgery using near-infrared imaging has been adopted to enhance intraoperative visualization in multiple surgical fields. In foregut surgery, calibration tubes are routinely used to calibrate crural closure but due to limited visibility carry a risk of iatrogenic injury, including esophageal or gastric perforation. Techniques that improve visualization of these devices may support safer intraoperative management.

Case Presentation:

A 75-year-old woman with a symptomatic paraesophageal hiatal hernia and partial gastric volvulus underwent robotic paraesophageal hiatal hernia repair with Toupet fundoplication. A FG gastric calibration tube (size 40 Fr, Endolumik Inc.), was inserted under near-infrared visualization and advanced down the esophagus and into the stomach. The device was used to (1) evacuate gastric contents, (2) guide tube positioning past the gastroesophageal junction, (3) inform mediastinal dissection/esophageal mobilization, (4) enable FG measuring of the length of esophageal mobilization below the diaphragm, and (5) calibrate both crural closure and fundoplication. The procedure was completed without intraoperative complications. The patient was discharged on postoperative day 1 and reported resolution of dysphagia at 8-week follow-up.

Discussion:

This case demonstrates the feasibility of FG calibration during robotic paraesophageal hernia repair. Continuous visualization of the calibration device provided an additional intraoperative reference during dissection in the setting of distorted anatomy. This approach may offer improved orientation compared with conventional calibration techniques, although its effect on clinical outcomes remains unknown.

INTRODUCTION

Fluorescence-guided (FG) surgery with near-infrared (NIR) imaging has emerged as an adjunct to improve intraoperative visualization in a variety of surgical fields. This technology enables real-time identification of anatomical structures and tissue perfusion, which may support surgical precision and intraoperative decision-making.^1–3

In foregut surgery, accurate identification of anatomical landmarks is essential for safe dissection and reconstruction. However, minimally invasive approaches rely primarily on visual cues and provide limited tactile feedback, which may increase the risk of technical error during dissection or instrumentation.⁴ Indocyanine green-based fluorescence imaging has been used to enhance visualization of vascular and biliary structures, including during laparoscopic cholecystectomy, where fluorescence cholangiography has been associated with improved visualization and clinical outcomes.^1,2,5

Calibration tubes are routinely used in procedures such as paraesophageal hernia repair and fundoplication to guide esophageal sizing and crural closure. Despite their widespread use, these devices carry a risk of iatrogenic injury, including esophageal or gastric perforation. Esophageal and gastric perforations have been reported during laparoscopic foregut surgery, including antireflux surgery and paraesophageal hernia repair.^4,6–8 These complications are associated with significant morbidity, particularly when recognition is delayed.^6,9

In addition to clinical consequences, complications in foregut surgery contribute substantially to increased healthcare utilization and cost. Postoperative complications are associated with prolonged hospital length of stay and increased resource use across surgical populations.¹⁰ In esophageal surgery, complications such as anastomotic leak have been shown to more than double overall treatment costs, largely due to intensive care utilization and extended hospitalization.¹¹ These findings highlight the importance of strategies aimed at improving intraoperative accuracy and reducing preventable injury.

Given these challenges, techniques that enhance visualization of instrumentation and surrounding anatomy may be beneficial. Early clinical evaluation of fluorescence-enabled calibration devices, as well as FG measuring in gastroesophageal surgery, has demonstrated feasibility and improved intraoperative visualization, although their effect on clinical outcomes has not yet been established.^12,13

In this context, we present a case demonstrating the use of a FG calibration device during robotic paraesophageal hiatal hernia repair with Toupet fundoplication to improve intraoperative visualization and dissection, as well as to facilitate FG measuring.

DEVICE DESCRIPTION

The Endolumik gastric calibration tube (EGCT, Endolumik Inc.) (Figure 1) is a single-use instrument available in 36- and 40-French sizes. The device obtained Food and Drug Administration (FDA) clearance on March 3, 2023, and was granted entry into the FDA’s Safer Technologies Program (STeP), a pathway for medical devices anticipated to provide meaningful safety advantages over existing standard-of-care treatments.

Figure 1.

Endolumik gastric calibration tube (EGCT) (A) and the distal end of the EGCT (B) which enables fluorescence-guided measurements up to 10 cm using a combination of lights and stripes.

The device measures 80 cm in length and contains an internal array of NIR LEDs that provide transillumination through the walls of the esophagus and stomach. To facilitate gastric decompression, irrigation, and leak testing, the device terminates in a rounded tip with lateral suction ports. The proximal handle contains the battery, suction regulator, standard suction connector, and a port for an external squeeze bulb and pressure gauge assembly used during leak testing. At the distal segment, three black bands are paired with LEDs spaced at 2-cm intervals, allowing intraoperative measurements based on the distance between LEDs.

MECHANISM OF ACTION: NIR FG

Standard visible light has limited tissue penetration beyond a few millimeters because it is readily scattered and absorbed by biological tissues. In contrast, NIR light can penetrate tissue to a greater depth, up to 1 cm, allowing visualization of the EGCT through overlying structures. Visualization of the EGCT does not require administration of indocyanine green, as the device contains integrated NIR LEDs that are detected using the robotic NIR/Firefly imaging system. NIR imaging is particularly useful when the device is obscured by overlying tissue, whereas transillumination and measurement markings may also be visible in standard white-light mode when the device is closer to the tissue surface. Both imaging modes were used during this procedure.

CASE DESCRIPTION

A 75-year-old woman with a past medical history of class III obesity (body mass index [BMI] 38 kg/m²), aortic stenosis after aortic valve replacement presented with a symptomatic paraesophageal hiatal hernia. She reported a 2-year history of intermittent epigastric pain and progressive dysphagia to both solids and liquids. Preoperative evaluation included an esophagogram and upper endoscopy, which demonstrated a large paraesophageal hiatal hernia with associated gastroesophageal reflux and partial organoaxial gastric volvulus (Figure 2). A transthoracic echocardiogram showed a preserved left ventricular ejection fraction of 60%, mild mitral and tricuspid regurgitation, and a well-functioning prosthetic aortic valve.

Figure 2.

Fluoroscopic esophagogram demonstrating a large type III PEH with Anteroposterior (A, B) and lateral (C, D) views. Lateral view (C) demonstrates gastric narrowing at the level of the diaphragm. The lateral view (D) shows partial organoaxial gastric volvulus.

Preoperative esophageal manometry was not performed due to both the severity of the patient’s dysphagia and the concern that the distorted gastric anatomy could complicate catheter placement and study interpretation, as well as the need to expedite operative management of the partial gastric volvulus. Given the patient’s significant preoperative dysphagia, a partial Toupet fundoplication was planned rather than a complete Nissen fundoplication to provide reflux control while minimizing the risk of postoperative dysphagia and gas bloat symptoms.

The patient underwent a robotic paraesophageal hiatal hernia repair with Toupet fundoplication. Intraoperatively, approximately 70% of the stomach was found to be herniated into the mediastinum. After reduction of the hernia contents, the 40 Fr Endolumik FG gastric calibration tube (EGCT) (Figure 3) was inserted under NIR visualization and advanced into the stomach. Although larger bougie sizes are commonly used during complete Nissen fundoplication,^14,15 the 40-Fr EGCT in this case was primarily used to facilitate visualization of the esophagus, gastric decompression, measurement of esophageal mobilization, and as a reference during crural closure and construction of the partial fundoplication. The device was not used as the sole determinant of the tightness of the cruroplasty or fundoplication.

Figure 3.

Introduction of EGCT, with device visualization in white light camera mode (A) and near-infrared light/Firefly camera mode (B).

The device was used to assist with mediastinal dissection by providing a continuous visual reference of the esophageal lumen (Figure 4). This aided in maintaining orientation during dissection and contributed to safe dissection and mobilization of the esophagus within the mediastinum. Adequate esophageal length was achieved with approximately 4-to-5 cm of intra-abdominal esophagus obtained (Figure 5).

Figure 4.

Mediastinal visualization demonstrating top anterior view (A), dissection of right mediastinum (B), and dissection of left mediastinum (C).

Figure 5.

Fluorescence-guided measuring using EGCT (white light mode) to measure the amount of esophageal mobilization below the diaphragm. The LEDs are spaced 2 cm apart, thus mobilization distance below diaphragm is greater than 4 cm.

The calibration tube was maintained in position during crural repair to guide hiatal closure. Posterior and anterior cruroplasty were performed using a running nonabsorbable barbed suture to approximate the diaphragmatic crura while avoiding excessive constriction. The device also facilitated gastric decompression during the procedure. A Toupet fundoplication was then constructed in standard fashion. No technical difficulties were encountered during insertion, advancement, or intraoperative use of the EGCT. Total operative time was 3 hours and 41 minutes. There were no intraoperative complications.

The postoperative course was uncomplicated. The patient was discharged on postoperative day 1. At follow-up visits at 10 days and 8 weeks, she reported significant improvement in dysphagia and resolution of preoperative symptoms.

DISCUSSION

FG calibration during paraesophageal hernia repair represents a potential adjunct to improve intraoperative visualization in a setting where anatomical distortion is common. In contrast to bariatric procedures, paraesophageal hernias are frequently associated with significant displacement of the stomach and gastroesophageal junction, which can complicate the safe placement and positioning of calibration devices. In this case, fluorescence-enabled transillumination allowed continuous visualization of the esophageal lumen during device advancement and mediastinal dissection.

Minimally invasive foregut surgery relies heavily on visual cues because tactile feedback is limited. Failure to accurately identify anatomical planes during dissection has been associated with iatrogenic injury, including esophageal or gastric perforation.^4,6 Instrumentation-related injury, including that associated with bougie placement, represents an additional source of risk.^7,8 Conventional calibration tubes are not directly visualized during minimally invasive surgery, which may contribute to misalignment or unrecognized injury. In this context, the ability to visualize the calibration device in real time may provide an additional layer of intraoperative feedback.

FG visualization in this case served as a continuous reference during mediastinal dissection and facilitated identification of the esophagus within the operative field. This function is conceptually similar to the use of indocyanine green fluorescence in other procedures, where enhanced visualization supports anatomical identification and also supports improved patient outcomes.⁵ The observed benefit in this case was improved orientation during dissection in the presence of distorted anatomy.

The integrated measurement markers on the calibration device provided a reproducible method to measure the extent of esophageal mobilization. Adequate mobilization of the esophagus is a key component of paraesophageal hernia repair, as insufficient intra-abdominal length has been associated with increased risk of recurrence. Intraoperative estimation of esophageal length is typically subjective. The use of a visual measurement reference may improve consistency in this step, although its impact on long-term outcomes remains unknown.

Calibration devices are also used during crural closure to avoid excessive narrowing of the hiatus. Overly tight closure may contribute to postoperative dysphagia, whereas inadequate closure may increase recurrence risk. Maintaining the calibration device in position during cruroplasty provided a visual and tactile reference for appropriate hiatal sizing in this case. This represents a standard principle of repair, with fluorescence serving as an adjunct to improve visualization rather than altering the technique itself.

The broader clinical significance of FG calibration remains to be defined. Early clinical evaluation of fluorescence-enabled calibration devices has demonstrated feasibility and improved intraoperative visualization, although evidence for reduction in complications or improvement in outcomes is limited.^12,13 Given the low incidence but high morbidity of complications such as esophageal perforation, even incremental improvements in intraoperative accuracy may be clinically meaningful, but this has not been established.

Postoperative complications in foregut surgery are associated with substantial increases in healthcare utilization and cost. Complications such as reoperation, respiratory failure, and prolonged hospitalization contribute significantly to overall expenditure.^16,17 In esophageal surgery, complications such as anastomotic leak have been shown to more than double total treatment costs.¹¹ Strategies that reduce technical error or improve intraoperative identification of anatomy may have downstream economic implications, although this relationship has not been directly evaluated for FG calibration. Subjectively, the NIR tube visualization helps the anesthesia provider and surgeon better see the device during introduction, giving the two a common visual reference point which we hypothesize leads to improved communication, and decreased risk of iatrogenic perforation at the gastroesophageal junction during device introduction into a revisional surgical field.^12,13

Device cost is similar to that of the most common disposable, nonlighted calibration tubes being used in minimally invasive surgery (which are approximately $120–$199 per device). Since the EGCT incorporates advanced visualization at a similar price, this results in increased quality without a significant impact on cost. In addition, when used for gastric evacuation and crural/wrap calibration, the EGCT eliminates the need for the following OR equipment: an orogastric tube and a reusable calibration tube. This results in the following savings of $4 for the orogastric tube, $80 for the sterilization cost for the reusable calibration tube. Although EGCT an additional disposable device expense, its ability to provide gastric decompression, calibration, visualization, and measurement may potentially reduce the need for additional intraoperative instrumentation such as endoscopy; however, formal cost-effectiveness analysis was not performed in this case.

Limitations and Future Directions

This report has several limitations. It describes a single case and does not allow assessment of reproducibility or comparative effectiveness. The observed advantages are based on intraoperative use and subjective assessment rather than objective outcome measures. In addition, the impact of FG calibration on complication rates, operative time, or long-term outcomes remains unknown.

Further study is required to evaluate the role of FG calibration in foregut surgery. Areas of interest include its application in complex or reoperative cases, its effect on device-related complications, and its potential role in standardizing intraoperative assessment of esophageal length. Prospective studies will be necessary to determine whether improved visualization translates into measurable clinical benefit.

CONCLUSION

FG gastric calibration during robotic paraesophageal hiatal hernia repair is feasible and may provide improved intraoperative visualization of the gastroesophageal junction and mediastinal esophagus. In this case, real-time transillumination of the calibration device supported anatomical orientation during dissection, facilitated assessment of esophageal mobilization, and assisted with hiatal closure. While these findings are limited to a single case and do not establish an effect on clinical outcomes, the ability to visualize calibration devices during minimally invasive foregut surgery represents a potential adjunct to standard techniques, particularly in the setting of distorted anatomy. Further investigation is required to determine whether this approach leads to measurable improvements in safety, reproducibility, or surgical outcomes.