Spectrophotometric assessment of bowel perfusion during low anterior resection: a prospective study

Evaluation of anastomotic blood supply during digestive tract reconstruction with the use of the oxygen saturation index: A pooling up analysis

PURPOSE

Anastomotic leakage (AL) is one of the most serious clinical complications in digestive tract reconstruction (DTR) surgery, and it is currently hypothesized that this may be related to insufficient anastomotic blood supply. Thus, Therefore, we aimed to assess the ability of tissue oxygen saturation(StO2) as a measure to evaluate anastomotic blood supply.

METHODS

A comprehensive literature search was performed using Embase, PubMed and Cochrane Library. StO2 was used as an evaluation index of anastomotic blood supply after DTR to analyze the potential association between this index and the occurrence of AL in the postoperative period.

RESULTS

A total of eleven articles involving 867 participants were included in this systematic review and meta-analysis. After pooling the standardized mean difference (SMD) and 95% confidence intervals (Cls), low StO2 was found to be an independent risk factor for AL (P < 0.00001; 95%CI: 1.02 [0.53-1.51]). The mean StO2 in the AL group (62.3%) was significantly lower than that in the non-AL group (74.3%); AL incidence increased with the reduction of StO2 to a certain value to 201.8% and 338.1% respectively.

CONCLUSION

Oxygen saturation index can be utilized in DTR to accurately and quantitatively evaluate the anastomotic blood supply to reduce the probability of postoperative AL.

Transverse Coloplasty Pouch versus Straight Coloanal Anastomosis Following Intersphincteric Resection for Low Rectal Cancer: the Functional Benefits May Emerge After Two Years

PURPOSE

This study aimed to compare the oncological and functional outcomes following intersphincteric resection (ISR) with transverse coloplasty pouch (TCP) or straight coloanal anastomosis (SCAA) for low rectal cancer.

METHODS

A single-center retrospective analysis was performed on patients with low rectal cancer who received ISR between January 2016 and June 2021. The primary endpoint was to compare the outcomes of bowel function within 1 year, 1 to 2 years, and 2 years after ileostomy closure in patients undergoing two different bowel reconstruction procedures (TCP or SCAA). The postoperative complications and oncological results were also compared between the two groups.

RESULTS

A total of 235 patients were enrolled in this study (SCAA group: 166; TCP group: 69). There was no significant difference in complications, including grades A-C anastomotic leakage (9.6% vs 15.9%), 3-year local recurrence rates (6.1% vs 3.9%), disease-free survival (82.4%vs 83.8%), or overall survival (94.1% vs 94.7%) between the two groups. Two years after ileostomy closure, 52.7% of patients in the SCAA group were assessed as having major low anterior resection syndrome (LARS), which was significantly higher than the 25.9% of patients in the TCP group (P = 0.014), but no difference was found prior to 2 years. Similar differences were seen in Wexner scores 2 years after surgery (P = 0.032). Additionally, TCP was an independent protective factor for postoperative bowel function as measured by both the LARS (OR, 0.28; 95% CI, 0.10-0.82; p = 0.020) and Wexner scoring (OR, 0.28; 95% CI, 0.09-0.84; p = 0.023).

CONCLUSION

This study suggests that TCP is a safe technique that may decrease bowel dysfunction after ISR for low rectal cancer compared with SCAA 2 years after ileostomy closure.

Intraoperative bowel perfusion assessment methods and their effects on anastomotic leak rates: meta-analysis

BACKGROUND

Anastomotic leak is one of the most feared complications of colorectal surgery, and probably linked to poor blood supply to the anastomotic site. Several technologies have been described for intraoperative assessment of bowel perfusion. This systematic review and meta-analysis aimed to evaluate the most frequently used bowel perfusion assessment modalities in elective colorectal procedures, and to assess their associated risk of anastomotic leak. Technologies included indocyanine green fluorescence angiography, diffuse reflectance spectroscopy, laser speckle contrast imaging, and hyperspectral imaging.

METHODS

The review was preregistered with PROSPERO (CRD42021297299). A comprehensive literature search was performed using Embase, MEDLINE, Cochrane Library, Scopus, and Web of Science. The final search was undertaken on 29 July 2022. Data were extracted by two reviewers and the MINORS criteria were applied to assess the risk of bias.

RESULTS

Some 66 eligible studies involving 11 560 participants were included. Indocyanine green fluorescence angiography was most used with 10 789 participants, followed by diffuse reflectance spectroscopy with 321, hyperspectral imaging with 265, and laser speckle contrast imaging with 185. In the meta-analysis, the total pooled effect of an intervention on anastomotic leak was 0.05 (95 per cent c.i. 0.04 to 0.07) in comparison with 0.10 (0.08 to 0.12) without. Use of indocyanine green fluorescence angiography, hyperspectral imaging, or laser speckle contrast imaging was associated with a significant reduction in anastomotic leak.

CONCLUSION

Bowel perfusion assessment reduced the incidence of anastomotic leak, with intraoperative indocyanine green fluorescence angiography, hyperspectral imaging, and laser speckle contrast imaging all demonstrating comparable results.

Assessment of Anastomotic Viability With Spectroscopic Real-time Oxygen Saturation Measurement in a Porcine Study

OBJECTIVE

Anastomotic leakage (AL) is a severe complication following intestinal procedures. Intra.Ox™ by ViOptix Inc (Newark, CA, USA) is a novel, FDA-approved spectroscopic device which enables real-time measurement of mixed tissue oxygen saturation (StO₂). Using a porcine model, this study explores the correlation between StO₂ measurements and AL formation as well as investigates the applicability of Intra.Ox™ in the clinical setting.

METHODS

Eleven female swine were divided into 3 groups to explore AL formation in different ischemic conditions. Group 1: 100% mesenteric-vascular ligation, n = 3; Group 2: 50% ligation, n = 5; Group 3: No mesenteric ligation, n = 3. StO₂ at the anastomotic line was measured before and after vessel ligation and anastomosis. Measurements were taken at 6 distinct locations along afferent and efferent loops. AL was evaluated on postoperative day 5 by re-laparotomy.

RESULTS

AL rate was 100%, 60% and 0% in groups 1, 2 and 3, respectively. Post-anastomotic StO₂ in group 1 (22.9 ± 18.5%) and 2 (39.2 ± 20.1%) were significantly lower than in group 3 (53.1 ± 8.3%, p<.0001). Post-anastomotic StO₂ readings ≤40% indicated AL potential with 100% sensitivity,+ 80% specificity, positive predictive value of 85.7% and negative predictive value of 100%.

CONCLUSION

This study demonstrates the value of Intra.Ox™ in assessing local perfusion and indicate the association between low StO₂ and AL by providing accurate, real-time, noninvasive tissue oxygenation measurements at anastomotic sites. Further studies are required to investigate the clinical application of this novel device in intestinal surgery.

Intraoperative fluorescence angiography and risk factors of anastomotic leakage in mini-invasive low rectal resections

BACKGROUND

One of the prerequisites for proper healing of the anastomosis after a colorectal resection is adequate blood supply to the connected intestinal segments. It has been proposed that adequate visualization of the blood flow using indocyanine green (ICG) could lead to the reduction in the incidence of anastomotic leakage (AL). The aim of this study was to assess the effectiveness of intraoperative fluorescence angiography (FA) in decreasing the incidence of AL after minimally invasive low anterior resection (LAR) with total mesorectal excision (TME) in rectal cancer patients and to determine predictors of anastomotic leak.

METHODS

From August 2015 to January 2019, data from 100 patients who underwent mini-invasive TME for rectal cancer using FA with indocyanine green (ICG) were prospectively collected and analyzed. They were compared with retrospectively analyzed data from a historical control group operated by one team of surgeons before the introduction of FA from November 2012 to August 2015 (100 patients). All patients from both groups were operated sequentially in one oncological center in Nový Jičín.

RESULTS

The incidence of AL was significantly lower in the ICG group (19% vs. 9%, p = 0.042, χ2 test). In fifteen patients in the ICG group (15%), the resection line was moved due to insufficient perfusion. Using Pearson's χ2 test, diabetes (p = 0.036) and application of a transanal drain (NoCoil) (p = 0.032) were identified as other risk factors (RFs) for AL.

CONCLUSION

The use of ICG to visualize tissue perfusion in low rectal resections for cancer can lead to a reduction of AL.

Noninvasive assessment of bowel blood perfusion using intraoperative laser speckle flowgraphy

PURPOSE

Laser speckle flowgraphy (LSFG) is a noninvasive method for quantitative evaluation of blood flow using the mean blur rate (MBR) as the blood flow index. We investigated whether LSFG can intraoperatively detect the demarcation line after vessel dissection and reduce the incidence of anastomotic leakage (AL).

METHODS

This study included 36 patients who underwent left-sided colorectal surgery. First, we compared the demarcation line (determined by LSFG) with the transection line (TL) at which the marginal vessels were divided. We then measured the MBR on both sides of the TL to determine where the MBR changed significantly. We investigated the presence or absence of significant differences between the MBR on the proximal side and that on the distal side of the TL. Finally, we retrospectively compared the patient characteristics and AL rates in the LSFG group (n = 36) and control group (n = 87).

RESULTS

In total, 58.3% (21/36) of the demarcation lines determined by LSFG matched the TL. The median distance between the demarcation line determined by LSFG and the TL was 0.0 mm (0.0-12.1 mm). The MBR sharply decreased at the TL in 80.6% (29/36) of cases. The median MBR was significantly lower on the distal than proximal side. The AL rate was not significantly lower in the LSFG group than in the control group.

CONCLUSION

LSFG accurately detected the demarcation line during surgery. However, LSFG did not reduce the incidence of AL.