The usefulness of fluorescence in decision-making strategy during bariatric and metabolic surgery

Abstract

Purpose

Fluorescence is used in various surgical fields to detect tissue ischemia. However, its use in obesity surgery is still limited. This study aims to investigate whether fluorescence can change surgical decisions during metabolic and bariatric surgery. The primary objective was to determine the proportion of patients with abnormal blood flow assessed by fluorescence and changes in intraoperative strategy. The second outcome measured was the morbidity and mortality within 30 days.

Methods

This single-centre, prospective observational study analysed patients who underwent primary metabolic and bariatric surgery. Data was collected from 66 consecutive patients who qualified for primary one anastomosis gastric bypass and Roux-en-Y gastric bypass procedures.

Results

In total, improper blood supply was observed in two cases, and surgical strategy was changed in 5.8% of OAGB and 2% of RYGB. No leakage incidents were reported. One patient (1.5%) experienced non-ischemic-related complications. No mortality was observed 30 days after the surgical procedures. No complications related to ICG administration were observed.

Conclusion

Despite the low incidence of tissue ischemia during metabolic and bariatric surgery, adding ICG fluorescence may potentially impact intraoperative surgical decisions due to ischemia detection during metabolic and bariatric surgery. However, this field lacks systematic data, and further research with a larger patient group is necessary to establish conclusive evidence.

Introduction

As the number of metabolic and bariatric surgeries (MBS) performed worldwide continues to rise, it is crucial to find effective solutions to reduce the risk of complications [1]. One of the most dangerous adverse events associated with MBS is leakage, which can result in high morbidity and mortality rates. The exact cause of MBS leaks is still unknown, but abnormal tissue blood supply can lead to leaks or anastomotic dehiscence after any abdominal surgery [2, 3].

Fluorescence has already been utilised in various surgical fields, including tissue ischemia detection, as it can potentially reduce complications [4–7]. It has ability to provide real-time, dynamic visualization of tissues and blood flow [8]. It has been particularly valuable in minimally invasive and laparoscopic surgeries, where direct visibility is limited. However, there is limited data on its use during MBS.

Aim

The study aimed to determine the possibility of change of surgical strategy due to introperative fluorescence use in MBS as the primary outcome. The secondary outcomes were the morbidity and mortality within 30 days.

Methods

The article was prepared according to the STROBE Reporting Guidelines. It is a single-centre, prospective study that analysed patients who underwent primary one anastomosis gastric bypass (OAGB) and Roux-en-Y gastric bypass (RYGB). Data were collected from July 2022 to November 2023. All patients who were qualified for surgery met the criteria for surgical obesity treatment [8]. All consecutive patients with primary OAGB and RYGB performed in our centre were included. The only exclusion criterion was the lack of consent to participate in the study. The database consisted of age, preoperative weight and body mass index (BMI), length of hospital stay and duration of the surgical procedures. 30-day morbidity and mortality data were collected at a follow-up visit one month after surgery. All complications were described according to the Clavien-Dindo classification [9].

Surgical technique

All patients received standard care following the Enhanced Recovery After Surgery (ERASB) Society Recommendations for bariatric surgery [10]. The dissection process started along the lesser curvature of the stomach, below the incisura angularis. Once the lesser sac was reached, the stomach was transacted with staplers transversely and vertically after the complete release of the fundus from the left diaphragmatic crus. A 34 F bougie was used to calibrate the pouch. After measuring 150 cm from the ligament of Treitz, a 2.5 cm stapled side-to-side gastrojejunal (GJ) anastomosis was performed. The first stage of the RYGB was performed similarly as in the OAGB. The pouch was shorter, with a length of 12 cm. After GJ anastomosis creation, a 150 cm long biliopancreatic limb was transected from the anastomosis with a stapler. Then, a 75 cm long alimentary limb was measured, and a 45 mm stapled side-to-side jejunojejunal (JJ) anastomosis was performed. Petersen’s space and mesenteric gap were closed in all cases of OAGB and RYGB using non-absorbable sutures.

Fluorescence assessment

The study protocol was created based on our centre’s experience and available evidence in the field due to the lack of a clear consensus on the use of fluorescence in MBS. The study protocol assumed the assessment of the gastrointestinal tract after performing anastomoses. Following the main stages of the surgery, 1 mg of indocyanine green (ICG), diluted in 1 ml of 0.9% sodium chloride solution, was administered through an intravenous catheter placed in the left antecubital fossa and followed by the flush of 10 ml of 0.9% sodium chloride solution. Simultaneously, an infrared camera was turned on (1588 AIM + SPY Fluorescence Technology by Stryker). The stomach and small intestine tissues were assessed in real-time for at least 90 s from the beginning of ICG detection in gastric and jejunal tissues for abnormal ICG flow. The level of tissue saturation was qualitatively assessed based on the decision of all surgeons in the surgical team as normal or abnormal (insufficient). The surgical strategy should be changed if an ischemic focus is detected to minimise the risk of complications. The occurrence of ischemia and the action method should be precisely documented in the operating protocol.

Results

Patients

The study included 66 patients, of whom 54 were women (81.8%). There were 17 OAGB and 49 RYGB. The group had a mean age of 41.8 ± 9.6 years, a mean preoperative BMI of 40.5 ± 5.6 kg/m2, and a mean preoperative weight of 114.1 ± 19.6 kg. The hospital stay lasted an average of 2.1 ± 0.3 days, and the surgery took an average of 122.8 ± 52.1 min, Table 1.

Table 1.

Patients’ characteristics

Variable	Value
Female/Male, n (%)	54(81.8%)/12(18.2%)
OAGB (n)	17
RYGB (n)	49
Age (mean) [years] ± SD (range)	41.8 ± 9.6 years (18–66)
Preoperative BMI (mean) [kg/m2] ± SD (range)	40.5 ± 5.6 (32.7–55.8)
Preoperative weight (mean) [kg] ± SD (range)	114.1 ± 19.6 85–169)
Preoperative weight loss (mean) [%] ± SD (range)	7.9 ± 5.6 (0-30.7)
Operative time (mean) [min] ± SD (range)	122.8 ± 52.1 (45–235)
Length of hospital stay (mean) [days] ± SD (range)	2.1 ± 0.3 (2–4)

Use of ICG

During all procedures, the ICG administration and fluorescence assessment protocol were utilised for all patients, with close attention to the perfusion assessment. In one of 17 OAGBs, impaired blood supply to the medial part of the GJ anastomosis was observed, Fig. 1. The ischemic site was invaginated with single absorbable sutures. The postoperative course was uneventful. Performing ICG assessment before and after anastomosis may be more sensitive in detecting ischemia. Fluorescence assessment of tissue blood supply before anastomosis may influence the decision to perform a primary anastomosis or change the surgical tactic, e.g., shortening the pouch in the event of its ischemia. Out of the 49 RYGB procedures performed, there was a single instance where the distal segment of the biliopacreatic limb, measuring roughly 1 cm, displayed a blue discolouration. Following the administration of ICG, venous stasis was ruled out, and ischemia was confirmed, Fig. 2. The intestinal mesentery was unharmed in the area of ischemia. The anomalous jejunal portion was excised with the linear stapler. No mortality was observed 30 days after the surgical procedures. In total, impaired blood supply was observed in two cases out of 66 (3%) and surgical strategy was changed in 5.8% of OAGB and 2% of RYGB.

Fig. 1.

GJ anastomosis– ischemia in the medial part of the pouch (the area of ​​ischemia is marked with a long white arrow, the gastric pouch is marked with a short white arrow and the jejunum is marked with two short white arrows)

Fig. 2.

Biliopancreatic limb ischemia (the area of ​​ischemia is marked with a white arrow)

Complications

No leakage incidents were reported. One patient (1.5%) who underwent RYGB suffered bleeding from the GJ anastomotic line and was successfully treated with hemoclips through endoscopy - the Clavien-Dindo Classification IIIa complication. Throughout the 30-day follow-up, no additional complications were observed, and there were no fatalities.

No complications related to ICG administration were observed.

Risk of bias

The primary risk of bias is the subjective evaluation of tissue fluorescence saturation with ICG rather than an objective quantitative assessment. Quantitative assessment was not possible at this stage of technology readiness due to the lack of nomograms for tissue saturation with ICG in the ischaemic tissue.

Discussion

Our research has shown that utilising ICG fluorescence in MBS can effectively impact the intraoperative surgical decision-making process. The test was feasible in all patients and was not associated with any side effects. Two patients showed reduced perfusion, which prompted us to adjust the surgical strategy.

The ICG administration protocol used in the study proved adequate for evaluating the tissue blood supply in all included patients. Observations indicate that most patients undergoing surgical treatment for obesity maintain normal tissue perfusion throughout the procedure. Furthermore, the utilization of ICG fluorescence imaging offers a valuable tool for verifying areas of potential ischemia that may appear suspicious upon macroscopic examination. Additionally, this method facilitates the early identification of abnormal vascular perfusion patterns, which may arise from intraoperative injury of small blood vessels, thereby contributing to improved surgical outcomes and enhanced patient safety.

Anastomotic leaks can be attributed to tissue ischemia, influenced by various well-known factors such as hypotension, inflammation, and smoking. To minimise the risk of anastomotic leakage, fluorescence technology in MBS is being explored, similar to the technology utilised in other areas of visceral surgery [3, 11, 12].

ICG has been used in medicine for a long time. Fluorescence is widely used during surgery to assess tissue blood supply, lymphatic vessel location or anastomosis leak test [4, 6, 13, 14].

Our team conducted extensive database research before planning the study. The number of publications dealing with fluorescence in MBS is still limited and mainly covers small numbers of patients with LSG as a primary procedure. In our previous publication, we categorised fluorescence functions based on their usefulness in the surgical treatment of obesity. This aided us in designing our current study [15].

To the best of our knowledge, this is the first published study regarding the use of ICG to assess tissue blood supply in OAGB [16–21]. Our findings support previous data published on detecting ischemia using fluorescence in MBS. Pavone et al. also reported a reduced risk of LSG-related leakage in patients receiving ICG compared to those who did not (1.2% vs. 2.5%) [17]. In our study, no leak occurred in patients with fluorescence-supported surgery. It is an improvement compared to the 0.4% of leaks after procedures performed in our centre during the last five years before the introduction of ICG. Balla et al. reported that in two patients (15.4%), a change in surgical strategy was necessary due to abnormal blood supply, which was confirmed by fluorescence. There were no complications. However, the study group consisted of only 13 patients [21]. Despite demonstrating proper blood flow of the gastric sleeve, one leak occurred in 43 LSGs, as described by Di Furia et al. This emphasises the multifactorial nature of the occurrence of leaks in MBS and confirms that ischemia is only one of the components that can potentially be eliminated using fluorescence [18]. So far, no randomised controlled trials on ICG-related reduction of complications after MBS are available, highlighting the need for further research before reaching definitive conclusions.

Limitations

A small sample size limits the study. However, it represents a significant contribution to fluorescence application in MBS, where research is currently lacking. Overall, this study advances knowledge and understanding in this field and can potentially guide future research efforts in this area.

Conclusion

The ICG fluorescence technique seems safe, adds little time to the operation, and can help surgeons in the field of intraoperative decision change. Despite the low incidence of tissue ischemia during MBS, the fluorescence assessment can potentially assist in the intraoperative decision-making process and may have the potential to reduce the risk associated with improper blood flow, and more extensive, randomised studies are necessary for a final conclusion. Furthermore the fluorescence use in MBS lacks systematic data; further research with a larger patient group is necessary in this field.

Author contributions

• Study conception and design MW, MJ • Acquisition of data MW, MJ, MB • Analysis and interpretation of data MW, MJ, ND • Drafting of manuscript MW, MJ, MB, ND • Table MW, ND• Figures MW, MJ • Critical revision of manuscript MJ, ND.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethical approval

The study was conducted according to the guidelines of the Declaration of Helsinki. The study was approved by the Bioethics Committee of Regional Medical Chamber in Gdańsk No. KB-32/22.

Informed consent

Informed consent was obtained from the participants included in the study.

Competing interests

The authors declare no competing interests.