High submucosal blood flow and low anastomotic tension prevent anastomotic leakage in rabbits

Evaluating Performance of Circular Staplers Using Comparative Test Methods for Evidence-Based Surgery

BACKGROUND

Circular stapler anastomosis is a common surgical procedure. Despite technological advancements, anastomotic leak remains a postoperative concern. Assessment of new technologies is impeded by variations in test methods and analysis, precluding outcome reproducibility and direct comparisons of results across studies. The development of robust and reproducible preclinical test methods is critical to accelerating stapling technology advancements.

METHODOLOGY

Leak pressure, staple line perfusion and security, and device removal force were quantified for triple-row (Tri-staple EEA, TriEEA) and double-row staplers (Echelon Circular Powered, ECP). Leak and perfusion testing were performed in vivo. Device removal force and staple line security testing were performed with synthetic medium using an Instron. Data were analyzed using unpaired student's t-test or Kruskal-Wallis test, with statistical significance defined as P < .05.

RESULTS

Leak pressure was 73% higher in TriEEA vs ECP (P = .016). TriEEA staple line failure force was lower than ECP at 40 and 50 mmHg (P = .001 and P = .023, respectively). Perfusion to the staple line was higher (148%) for TriEEA than for ECP (P = .003) and the force required to remove the device from its stapled anastomosis was 78% lower for TriEEA than for ECP (P < .001).

DISCUSSION/CONCLUSIONS

This report addresses a primary limitation in stapling research by presenting novel methodologies which enhance clinical relevance and provide sufficient detail for reproduction by independent investigators. These methods are applied to a comparison between triple-row and double-row staplers to demonstrate utility of new test methods in assessing key technology design features.

Qualitative features of esophageal fluorescence angiography and anastomotic outcomes in children

BACKGROUND

Indocyanine green (ICG) is commonly used to assess perfusion, but quality defining features are lacking. We sought to establish qualitative features of esophageal ICG perfusion assessments, and develop an esophageal anastomotic scorecard to risk-stratify anastomotic outcomes.

METHODS

Single institution, retrospective analysis of children with an intraoperative ICG perfusion assessment of an esophageal anastomosis. Qualitative perfusion features were defined and a perfusion score developed. Associations between perfusion and clinical features with poor anastomotic outcomes (PAO, leak or refractory stricture) were evaluated with logistic and time-to-event analyses. Combining significant features, we developed and tested an esophageal anastomotic scorecard to stratify PAO risk.

RESULTS

From 2019 to 2021, 53 children (median age 7.4 months) underwent 55 esophageal anastomoses. Median (IQR) follow-up was 14 (10-19.9) months; mean (SD) perfusion score was 13.2 (3.4). Fifteen (27.3%) anastomoses experienced a PAO and had significantly lower mean perfusion scores (11.3 (3.3) vs 14.0 (3.2), p = 0.007). Unique ICG perfusion features, severe tension, and primary or rescue traction-induced esophageal lengthening [Foker] procedures were significantly associated with PAO on both logistic and Cox regression. The scorecard (range 0-7) included any Foker (+2), severe tension (+1), no arborization on either segment (+1), suture line hypoperfusion >twice expected width (+2), and segmental or global areas of hypoperfusion (+1). A scorecard cut-off >3 yielded a sensitivity of 73% and specificity of 93% (AUC 0.878 [95%CI 0.777 to 0.978]) in identifying a PAO.

CONCLUSIONS

A scoring system comprised of qualitative ICG perfusion features, tissue quality, and anastomotic tension can help risk-stratify esophageal anastomotic outcomes accurately.

LEVELS OF EVIDENCE

Diagnostic - II.

Predictive and Diagnostic Biomarkers of Anastomotic Leakage: A Precision Medicine Approach for Colorectal Cancer Patients

Development of an anastomotic leak (AL) following intestinal surgery for the treatment of colorectal cancers is a life-threatening complication. Failure of the anastomosis to heal correctly can lead to contamination of the abdomen with intestinal contents and the development of peritonitis. The additional care that these patients require is associated with longer hospitalisation stays and increased economic costs. Patients also have higher morbidity and mortality rates and poorer oncological prognosis. Unfortunately, current practices for AL diagnosis are non-specific, which may delay diagnosis and have a negative impact on patient outcome. To overcome these issues, research is continuing to identify AL diagnostic or predictive biomarkers. In this review, we highlight promising candidate biomarkers including ischaemic metabolites, inflammatory markers and bacteria. Although research has focused on the use of blood or peritoneal fluid samples, we describe the use of implantable medical devices that have been designed to measure biomarkers in peri-anastomotic tissue. Biomarkers that can be used in conjunction with clinical status, routine haematological and biochemical analysis and imaging have the potential to help to deliver a precision medicine package that could significantly enhance a patient's post-operative care and improve outcomes. Although no AL biomarker has yet been validated in large-scale clinical trials, there is confidence that personalised medicine, through biomarker analysis, could be realised for colorectal cancer intestinal resection and anastomosis patients in the years to come.

Using simple interrupted suture anastomoses may impair translatability of experimental rodent oesophageal surgery

Background/purpose: Irreproducibility and missing translatability are major drawbacks in experimental animal studies. Hand-sewn anastomoses in oesophageal surgery are usually continuous, whereas those in experimental oesophageal surgery are widely performed using the simple interrupted technique. It has been implicated to be inferior in tolerating anastomotic tension, which we aimed to test in rats due to their importance as an animal model in oesophageal surgery.Methods: We determined linear breaking strengths for the native oesophagus (n = 10), the simple interrupted suture anastomosis (n = 11), and the simple stitch (n = 9) in 8-week old Sprague-Dawley rats. Experiments were powered to a margin of error of 10% around the results of exploratory investigations. The comparison of anastomotic resilience between native organ and simple interrupted suture anastomosis was a priori powered to 99%.Results: Native oesophagi sustained traction forces of 4.25 N (95% CI: 4.03-4.58 N), but the simple interrupted suture anastomosis had only 38.6% (Δ= -2.78 N, 95% CI: -2.46 to -3.11 N, p < .0001) of the resilience of native oesophagi.Conclusions: Oesophageal division and re-anastomosis markedly decreases resilience to traction forces compared to the native organ. This effect is even more pronounced in rats compared to other species and might impair transferability of results.

Vertical Alveolar Augmentation Using BMP-2/ACS/Allograft with Printed Titanium Shells to Establish an Early Vascular Scaffold

Traditional reconstruction of major alveolar ridge deficiency has required autogenous cortical cancellous particulate bone grafts, often augmented with particulate allogeneic components. Now there is a new concept to consider, that of orthoalveolar form. This paradigm shift involves components of the tissue engineering triad of inductive growth factors combined with a matrix and stem cells, together with osteotomies or devices designed for space maintenance. Reported here is early experience with computer technology used to redesign deficient alveolar ridges deriving ideal alveolar-shaped bone-forms made from powdered titanium, sintered by laser at high temperature using rapid prototype technology.

Real-time intraoperative detection of tissue hypoxia in gastrointestinal surgery by wireless pulse oximetry

OBJECTIVE

Dehiscence or leakage after bowel anastomoses is associated with high morbidity and mortality. Perfusion and local tissue oxygenation (StO2), independent of systemic oxygen saturation, are fundamental determinants of anastomotic viability. Because current technology is limited for monitoring local StO2 at bowel anastomoses, our goal was to construct a wireless pulse oximeter (WiPOX) to monitor real-time intraoperative tissue oxygenation, permitting identification of compromised anastomotic perfusion.

METHODS

We have: (a) designed a handheld device capable of real-time monitoring of serosal and mucosal StO2 through endoscopic ports with wireless data transmission to standard intraoperative monitors, (b) constructed the WiPOX using materials meeting FDA regulations for intraoperative use and reuse, (c) performed accuracy testing in humans by comparing the WiPOX to standard pulse oximeters, and (d) tested WiPOX efficacy for detecting early tissue hypoxia in stomach, intestines, and kidneys in anesthetized rats and swine.

RESULTS

In humans, WiPOX demonstrated accuracy within 3% compared with commercially available pulse oximeters. Application of the WiPOX in rats and swine demonstrated normal serosal and mucosal StO2 and pulse rates in healthy small bowel and stomach. Within 30 s of compromised perfusion, the WiPOX detected bowel hypoxia over a wide range of oxygen saturation (p<0.005). A greater degree of hypoxia was detected in mucosal versus serosal measurements during early ischemia, despite normal appearance of tissue. The onboard sensor-processor unit permitted noninvasive pulse oximetry and integration with current intraoperative monitoring. The contact pressure-sensing head allowed for consistent, high-quality StO2 waveform readouts despite the presence of body fluids.

CONCLUSIONS

We have constructed, validated, and successfully tested a novel wireless pulse oximeter capable of detecting intraoperative tissue hypoxia in open or endoscopic surgery. This device will aid surgeons in detecting anastomotic vascular compromise and facilitate choosing an ideal site for bowel anastomosis by targeting well-perfused tissue with optimal healing capacity.

Efficacy of postoperative elective ventilatory support for leakage protection in primary anastomosis of congenital esophageal atresia

Anastomotic complications after primary repair of congenital esophageal atresia (EA) are recognized and feared complications. A close association exists between anastomotic leakage and the tension of the anastomosis on the suture line. This study aimed to evaluate the efficacy of postoperative elective ventilation support (PEVS) under paralysis with neck flexion after primary repair of EA. Forty-two EA patients; 4 cases with type A and 38 with type C by Gross classification received primary or delayed primary anastomosis between 1979 and 2003. PEVS has been introduced in the postoperative management of all EA cases since 1998. Vecuronium bromide was administered together with fentanyl citrate for five postoperative days. Patients were retrospectively divided into two groups: with or without PEVS management. There was no difference in operation data such as gastrostomy construction, gap between esophageal upper and lower pouch, primary or delayed primary anastomosis. PEVS under paralysis with neck flexion reduced postoperative anastomotic leakages in primary anastomosis with or without a Livaditis procedure. PEVS did not adversely increase anastomotic stricture, atelectasis, severe gastro-esophageal reflux, prolong days on ventilatory support or decrease survival rate. PEVS is an effective management method to decrease anastomotic complications for EA neonates.

A new concept for esophageal resection--prevascularization: an experimental study

We aim to elaborate upon a basically new animal model for esophageal resection. A total of 17 operations on 10 dogs were performed in order to develop a model in which resection of the cervical part of the esophagus involves two steps. The first step comprises omental flap transplantation from the abdomen to the cervical region by a microsurgical method, this omental flap improving the blood supply to the organ (prevascularization). The second step is segmental resection of the esophagus 14 days later. Of the five transplanted grafts, four still survived one week after the operation; for technical reasons, one flap had thrombotized. In the two long-term survival cases with esophageal resection after prevascularizastion, there were no major complications: the resections were successful, and the omental flap 'grew into' the tissue structure of the esophagus, assisting the healing of the anastomosis. Segmental resection of the cervical part of the esophagus was performed successfully via a new type of operation on dogs.

Significance of the clinical course and early upper gastrointestinal studies in predicting complications associated with repair of esophageal atresia

BACKGROUND/PURPOSE

In many centers, use of upper gastrointestinal (UGI) contrast studies in the early postoperative period after esophageal atresia (EA) repair is considered routine. Indications for this are many, including searching for existing problems and predicting future complications. However, most major complications, both early and late, usually are identified clinically before any radiologic studies. The purpose of this study was to investigate factors that may anticipate the development of postoperative complications after EA repair, looking particularly at the predictive value of routine early postoperative UGI studies.

METHODS

A total of 111 consecutive cases of EA were identified retrospectively over a 10-year period from 2 major Canadian pediatric health centers. One hundred one were associated with a distal tracheoesophageal fistula (TEF), of which, 90 had repairs. Ninety-seven percent of these had a UGI study at a median of 9.1 postoperative days (range, 2 to 23) before consideration of oral feeding. Charts were reviewed looking at patient variables, surgical factors, early UGI findings, and postoperative courses. Complications that required intervention were noted, including anastomotic leaks, gastroesophageal reflux (GER), strictures, and recurrent and missed fistulae. All initial UGI studies were reexamined by 1 of 2 pediatric radiologists. Logistic regression was used to examine relationships between these clinical and radiologic variables and outcomes.

RESULTS

Of the variables analyzed, univariate analysis showed clinically significant leaks to be associated with intraoperative factors (subjective degree of anastomotic tension, and the use of myotomies) and early postoperative clinical evidence suggesting a leak. In a multivariate model, all remained independently significant except for the use of myotomies. Later development of clinically significant GER also was associated with the degree of tension. It had no relationship, however, with findings of dysmotility, esophageal shortening, or reflux at the initial UGI study. Development of a stricture requiring dilatations or resection was associated with a history of clinically evident GER only; no relationships were seen with a history of an anastomotic leak or any other clinical, operative, or radiographic variables. Missed or recurrent fistulae were all suspected clinically before radiologic confirmation.

CONCLUSIONS

Early and late complications after repair of EA can be identified and potentially anticipated based on clinical findings at the time of repair and during the postoperative period. The use of early "routine" UGI studies, with no suspicion of a problem, has little value in terms of predicting complications or future clinical course.