Comparison between orogastric tube/bougie and a suction calibration system for effects on operative duration, staple-line corkscrewing, and esophageal perforation during laparoscopic sleeve gastrectomy

This was a single-center, single-surgeon prospective study. Informed consent was obtained from all individual participants included in the study. Primary LSG was performed using either a 40-Fr bougie or a 40-Fr suction calibration system (SCS), the ViSiGi 3D™, in alternating order, with the decision to use either device in the first case being determined at random. Sex, age, body mass index (BMI), and comorbidity information were recorded for each patient.

To determine the staple-line straightness, three measurements were taken at three predetermined locations on the inflated, excised gastric specimen: circumference, and distances from the greater curvature to the staple line anteriorly and posteriorly (Figs. 2, 3). The three predetermined locations were the midpoint of the staple line and the points 5 cm above and below the midpoint. The variance of deviation from the midline at these locations was calculated for each specimen. To standardize the amount of inflation, each specimen was connected to the same gas source for 5 s through an insufflation needle.

The number of device movements was recorded in both groups. This included the number of intraluminal devices inserted, as well as the number of times the surgeon inquired about the status/location of the devices; e.g., asking the anesthesiologist “Is it in?” or “Is it out?” or to move or hold the device in place, or to insert or remove any intraluminal tube, and any repositioning of the device.

Visual confirmation of device position was captured in an intraoperative photograph of each stomach prior to the first staple firing. To assess the degree of visualization of both devices, five out of thirteen photographs from each study group were randomly chosen and paired side by side for comparison (Fig. 1). During the 19th World Congress IFSO 2014 (International Federation for the Surgery of Obesity and Metabolic Disorders) in Montreal, Canada, 273 attending surgeons were asked to participate in a survey in which they answered the same question for all five pairs of photographs: “In which of the two images below can you better identify the calibration system along the lesser curvature (bougie, etc.)?” The result of the survey demonstrates whether there is a visual difference between bougie and SCS, which directly relates to the safety and effectiveness of the device.

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Statistical analysis

Statistical analysis was performed with a two-sample t test assuming unequal variance. In addition, staple-line straightness analysis was performed with one-way analysis of variance (ANOVA) using StatPlus^® software (AnalystSoft, Inc., Alexandria, VA, USA).

The equation is given as follows:

$$ V_{{\text{[top}}, \,{\text{middle}},\, {\text{or}} \,{\text{bottom}}]} = D_{\text{anterior}} - D_{\text{posterior}},$$

where D _anterior represents anterior distance from greater curvature to staple line, D _posterior represents posterior distance from greater curvature to staple line and V _{[top, middle, or bottom]} represents the difference between the two at one of the three points along the greater curvature. A positive number indicates a posteriorly deviated staple line, and a negative number indicates an anteriorly deviated staple line (Fig. 2). For a straight staple line, the difference between the distances from greater curvature to anterior and posterior edges would be the same at all three predetermined locations (Fig. 3),

$$ V_{\text{top}} = \, V_{\text{middle}} = \, V_{\text{bottom}}. $$

A variance of zero between V _top, V _middle, and V _bottom indicates identical values signifying a straight staple line. A small variance indicates closer data points, whereas a large variance indicates more widespread data points representing a greater degree of corkscrewing (Fig. 4).

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New technology

The ViSiGi 3D™ calibration system is indicated for use in gastric and bariatric surgical procedures for the application of suction, stomach decompression, drainage of gastric fluids, and irrigation, and to serve as a sizing guide. Compared with a bougie, which must be used in combination with other apparatuses, the anesthesiologist inserts the ViSiGi 3D™ only once at the beginning of the case and removes it after stapling and leak testing are completed (Fig. 5a). The circumferential fenestration pattern at the distal end of the ViSiGi 3D™ facilitates complete suction decompression of the stomach prior to trocar placement (Fig. 5b). This pattern also applies uniform suction on both the anterior and posterior sides of the stomach, creating equal tension on the staple line. The integrated suction regulator reduces the high pressure normally found in the operating room (600 mmHg or more) to 125 mmHg, a clinically safe level for gastric tissues (Fig. 5c). The combination of the one-way valve and the fenestration allows air or methylene blue to be passed, so leak testing can be performed with the device in place. The ViSiGi 3D™ also includes an accessory bulb that delivers controlled air pressure during a leak test.

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The number of device movements for both groups was recorded. The average number of tube movements was 8.1 (range 8–11) for the OG-bougie-OG system versus 3.6 (range 3–4) for the ViSiGi 3D™ (p < 0.0001). Typical bougie movements included introducing the OG tube for stomach decompression, removing the OG tube, inserting the bougie for sleeve sizing, surgeon asking the question: “Is there anything else inside the stomach?” holding the bougie in place during stapling, removing the bougie, inserting the OG tube for leak testing, and removing the OG tube.

According to the most recent International Sleeve Gastrectomy Expert Panel Consensus statement [5], stricture formation should be avoided during sleeve gastrectomy. Additionally, among concepts found to be most important to experts: 75 % felt that “maintaining symmetrical lateral traction while stapling will reduce potential strictures”; 82 % felt the “use of a bougie when stapling the incisura angularis will result in decreased incidence of strictures,” and all experts surveyed agreed that “the incisura angularis is a potential stricture site.”

However, a bougie used for calibration has no internal stability. If gastric tissues are overextended during stapling, the elasticity of the tissues will lead to tissue retraction, and may result in stricture, especially near the incisura angularis. Uniform circumferential suction allows the anterior and posterior walls to envelope the SCS, which guides staple placement, decreasing the incidence of strictures.

With a 1 % incidence, stricture is the second most prevalent early complication, and most symptomatic within 6 weeks postoperatively [6, 7, 8, 9, 10, 11, 12]. Treatment options vary, and some authors are proponents of a silicone-covered nitinol stent in an attempt to cause scarred permanent dilatation. One author has advocated several forms of gastroplasty to keep the sleeve intact, such as a stapled end-to-end gastrogastrostomy with transoral anvil passage, local excision with a vagus-preserving, hand-sewn stapled end-to-end gastrogastrostomy, or a transverse linear gastroplasty. However, Roux-en-Y gastric bypass remains the best surgical treatment for persistent strictures after endoscopic treatments have failed.

Corkscrewing of the staple line has been discussed at meetings and in books [4, 15]; but this form of functional kink or spiraling has not been well studied. Because of gastric tissue elasticity, it is possible to apply uneven tension on the anterior and posterior walls as the posterior stomach is examined for redundant tissue during stapling. Our results suggest that the ViSiGi 3D™ provides controlled and uniform suction, which may enable symmetrical lateral traction, thus preventing corkscrewing. This can potentially decrease the incidence of dysphagia and malnutrition, including water-soluble vitamin deficiencies. Prevention is preferable to excision of a corkscrewed sleeve and conversion to Roux-en-Y gastric bypass.

Perforation, which can occur if bougie or the tube used is too rigid, is a complication to both patients and hospitals [3]. The ViSiGi 3D™ incorporates a fenestration pattern that makes the distal tip more flexible, which may contribute to reducing the risk of perforation. Also, with the OG-bougie-OG system, the anesthesiologist has to insert and remove three intraluminal tubes during the surgery. Thus, consolidation of these three tasks into one using the ViSiGi 3D™ confers an additional threefold reduction in the risk of perforation.

Additionally, intraluminal tubes such as temperature probes, OG tubes, and bougies have been inadvertently transected during stapling and creation of the sleeve [2, 13, 14]. At any time during surgery, a bougie can slip out of the unfinished sleeve, after which it can be easily transected proximally. Accidental stapling of these tubes can cause significant morbidity and require prolonged operating time for repair. In certain cases, postoperative complications may include stricture or leak. A calibration system that is easily visualized and stays anchored along the lesser curvature provides a clinical advantage. In our survey of surgeons, 91.5 % found the ViSiGi 3D™ enabled clearer, more direct visualization of the device and made the stapling process easier and safer.

By integrating multiple steps into one, the ViSiGi 3D™ significantly reduced the operating time needed to complete each step of a sleeve gastrectomy and therefore the total operating time. Based on the clinical benefits found in the present study, we recommend incorporating the ViSiGi 3D™ into the LSG protocol.

Our study objectively examined and compared the degree of staple-line spiraling in LSG. Larger studies are needed to investigate the effect of suction on corkscrewing of the staple line. Despite our small sample size, the preliminary results of the present study appear encouraging. In addition, the limit of this study includes the inability to blind the surgeon to whether the patient was receiving a bougie or a SCS, which could potentially introduce bias. Due to the mechanism of SCS, which requires the surgeon to instruct the anesthesiologist turning on and off suction, the surgeon needs to know which device was using ahead of time. The blinded portion of the study was the survey conducted during IFSO. To ensure objectivity of the interpretation, the 273 surgeons were neither informed about the study nor aware of a new device. They were simply asked the question: “In which of the two images below can you better identify the calibration system along the lesser curvature (bougie, etc.)?”