Tissue Oximetry as a Potential Alternative to Indocyanine Green (ICG) Perfusion Assessment in Colorectal Anastomotic Cases.

INTRODUCTION: Anastomotic margin tissue perfusion is recognized as critical to successful colorectal anastomosis creation. Near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) is the most common modality used by surgeons as an adjunct to clinical assessment in confirming the adequacy of tissue perfusion. Tissue oxygenation as a surrogate for tissue perfusion has been described in a variety of surgical specialties but its use in colorectal surgery has been limited. Here, we report our experience using a handheld tissue-oxygen meter, IntraOx, for the evaluation of colorectal tissue bed oxygen saturation (StO 2 ) and compared its utility with NIR-ICG in identifying the viability of colonic tissue before anastomosis in a range of colorectal procedures. MATERIALS AND METHODS: This was an institutional review board-approved multicenter trial consisting of 100 patients undergoing elective colon resections. After specimen mobilization, a clinical margin was chosen based on the oncologic, anatomic, and clinical assessment as per the clinicians' standard technique. The IntraOx device was then used to take a baseline reading of colonic tissue oxygenation on a normal segment of perfused colon. Following this, measurements were taken circumferentially at 5 cm intervals along the bowel proximally and distally to the clinical margin. A StO 2 margin was then determined based on the point at which the StO 2 dropped off by ≥10 percentage points. This was then compared with the NIR-ICG margin using the Spy-Phi system. RESULTS: StO 2 was found to have a sensitivity and specificity of 94.8% and 93.1%, respectively, and a positive predictive value and negative predictive value of 93.5% and 94.5%, respectively when compared with NIR-ICG. At the 4-week follow-up, no significant complications or leaks were reported. CONCLUSIONS: The IntraOx handheld device was found to be similar to NIR-ICG in identifying a well-perfused margin of colonic tissue while having the added benefits of high portability and reduced costs. Further studies looking at the effect of the IntraOx on preventing colonic anastomotic complications such as leak and stricture are warranted.

The use of tissue oxygen measurements compared to indocyanine green imaging for the assessment of intraoperative tissue viability of human bowel.

BACKGROUND: Adequate tissue oxygenation and perfusion remain fundamental to safe bowel resection surgery. Near infrared (NIR) imaging using indocyanine green has proven itself superior to clinical evaluation alone in assessing bowel perfusion, but requires expensive equipment not readily available in many centers. METHODS: We studied the IntraOx device (Vioptix Inc, Newark, CA USA), a handheld, tissue oxygen saturation assessment tool, to assess whether tissue bed oxygen saturation (StO2) is comparable to NIR assessment of bowel viability. Patients undergoing elective colon resection for benign and malignant disease were included. After choosing a clinical margin (CM) and dividing the mesentery, StO2 was measured at 5-cm intervals along the colon. A tissue oxygen saturation margin (TOM) was assigned where StO2 dropped off by at least 10 percentage points. NIR perfusion was then assessed to determine NIR margin (NIRM). Intraoperative and postoperative data were collected. RESULTS: 32 consecutive patients undergoing colectomies were analyzed. IntraOx sensitivity was 90.6%, specificity was 94.3%. The mean StO2 difference across the NIRM was 23.1%. In all but one case, the TOM matched the NIRM. In 3 cases, the TOM and NIRM concurred, but were a mean of 3.3 cm proximal to the CM and altered the surgical plan. At 4-week follow-up, no significant complications were reported. CONCLUSIONS: The IntraOx device consistently identified a margin of significant saturation "drop-off" which correlated with the findings on NIR perfusion and clinical assessment. These early data indicate that StO2 measurement may be equivalent to NIR assessment of bowel perfusion. In addition, the IntraOx device may be a more cost-effective solution for surgeons looking for adjunctive evaluation of bowel viability. More study is warranted in a larger group of patients to confirm these preliminary findings and to judge the impact of StO2 assessment on reducing anastomotic leaks.

Perfusion Assessment in Left-Sided/Low Anterior Resection (PILLAR III): A Randomized, Controlled, Parallel, Multicenter Study Assessing Perfusion Outcomes With PINPOINT Near-Infrared Fluorescence Imaging in Low Anterior Resection.

BACKGROUND: Indocyanine green fluoroscopy has been shown to improve anastomotic leak rates in early phase trials. OBJECTIVE: We hypothesized that the use of fluoroscopy to ensure anastomotic perfusion may decrease anastomotic leak after low anterior resection. DESIGN: We performed a 1:1 randomized controlled parallel study. Recruitment of 450 to 1000 patients was planned over 2 years. SETTINGS: This was a multicenter trial. PATIENTS: Included patients were those undergoing resection defined as anastomosis within 10 cm of the anal verge. INTERVENTION: Patients underwent standard evaluation of tissue perfusion versus standard in conjunction with perfusion evaluation using indocyanine green fluoroscopy. MAIN OUTCOME MEASURES: Primary outcome was anastomotic leak, with secondary outcomes of perfusion assessment and the rate of postoperative abscess requiring intervention. RESULTS: This study was concluded early because of decreasing accrual rates. A total of 25 centers recruited 347 patients, of whom 178 were randomly assigned to perfusion and 169 to standard. The groups had comparable tumor-specific and patient-specific demographics. Neoadjuvant chemoradiation was performed in 63.5% of perfusion and 65.7% of standard (p > 0.05). Mean level of anastomosis was 5.2 ± 3.1 cm in perfusion compared with 5.2 ± 3.3 cm in standard (p > 0.05). Sufficient visualization of perfusion was reported in 95.4% of patients in the perfusion group. Postoperative abscess requiring surgical management was reported in 5.7% of perfusion and 4.2% of standard (p = 0.75). Anastomotic leak was reported in 9.0% of perfusion compared with 9.6% of standard (p = 0.37). On multivariate regression analysis, there was no difference in anastomotic leak rates between perfusion and standard (OR = 0.845 (95% CI, 0.375-1.905); p = 0.34). LIMITATIONS: The predetermined sample size to adequately reduce the risk of type II error was not achieved. CONCLUSIONS: Successful visualization of perfusion can be achieved with indocyanine green fluoroscopy. However, no difference in anastomotic leak rates was observed between patients who underwent perfusion assessment versus standard surgical technique. In experienced hands, the addition of routine indocyanine green fluoroscopy to standard practice adds no evident clinical benefit. See Video Abstract at http://links.lww.com/DCR/B560. VALORACIN DE LA IRRIGACIN DE LADO IZQUIERDO/RESECCIN ANTERIOR BAJA PILAR III UN ESTUDIO ALEATORIZADO, CONTROLADO, PARALELO Y MULTICNTRICO QUE EVALA LOS RESULTADOS DE LA IRRIGACIN CON PINPOINT IMGENES DE FLUORESCENCIA CERCANA AL INFRARROJO EN LA RESECCIN ANTERIOR BAJA: ANTECEDENTES:Se ha demostrado que la fluoroscopia con verde de indocianina mejora las tasas de fuga anastomótica en ensayos en fases iniciales.OBJETIVO:Nuestra hipótesis es que la utilización de fluoroscopia para asegurar la irrigación anastomótica puede disminuir la fuga anastomótica luego de una resección anterior baja.DISEÑO:Realizamos un estudio paralelo, controlado, aleatorizado 1:1. Se planificó el reclutamiento de 450-1000 pacientes durante 2 años.AMBITO:Multicéntrico.PACIENTES:Pacientes sometidos a resección definida como una anastomosis dentro de los 10cm del margen anal.INTERVENCIÓN:Pacientes que se sometieron a la evaluación estándar de la irrigación tisular contra la estándar en conjunto con la valoración de la irrigación mediante fluoroscopia con verde indocianina.PRINCIPALES VARIABLES EVALUADAS:El principal resultado fue la fuga anastomótica, y los resultados secundarios fueron la evaluación de la perfusión y la tasa de absceso posoperatorio que requirió intervención.RESULTADOS:Este estudio se cerró anticipadamente debido a la disminución de las tasas de acumulación. Un total de 25 centros reclutaron a 347 pacientes, de los cuales 178 fueron, de manera aleatoria, asignados a perfusión y 169 a estándar. Los grupos tenían datos demográficos específicos del tumor y del paciente similares. Recibieron quimio-radioterapia neoadyuvante el 63,5% de la perfusión y el 65,7% del estándar (p> 0,05). La anastomosis estuvo en un nivel promedio de 5,2 + 3,1 cm en perfusión en comparación con 5,2 + 3,3 cm en estándar (p> 0,05). Se reportó una visualización suficiente de la perfusión en el 95,4% de los pacientes del grupo de perfusión. El absceso posoperatorio que requirió tratamiento quirúrgico fue de 5,7% de los perfusion y en el 4,2% del estándar (p = 0,75). Se informó fuga anastomótica en el 9,0% de la perfusión en comparación con el 9,6% del estándar (p = 0,37). En el análisis de regresión multivariante, no hubo diferencias en las tasas de fuga anastomótica entre la perfusión y el estándar (OR 0,845; IC del 95% (0,375; 1,905); p = 0,34).LIMITACIONES:No se logró el tamaño de muestra predeterminado para reducir satisfactoriamente el riesgo de error tipo II.CONCLUSIÓN:Se puede obtener una visualización adecuada de la perfusión con ICG-F. Sin embargo, no se observaron diferencias en las tasas de fuga anastomótica entre los pacientes que se sometieron a evaluación de la perfusión versus la técnica quirúrgica estándar. En manos expertas, agregar ICG-F a la rutina de la práctica estándar no agrega ningún beneficio clínico evidente. Consulte Video Resumen en http://links.lww.com/DCR/B560. (Traducción-Dr Juan Antonio Villanueva-Herrero).

Perfusion assessment in laparoscopic left-sided/anterior resection (PILLAR II): a multi-institutional study.

BACKGROUND: Our primary objective was to demonstrate the utility and feasibility of the intraoperative assessment of colon and rectal perfusion using fluorescence angiography (FA) during left-sided colectomy and anterior resection. Anastomotic leak (AL) after colorectal resection increases morbidity, mortality, and, in cancer cases, recurrence rates. Inadequate perfusion may contribute to AL. The PINPOINT Endoscopic Fluorescence Imaging System allows for intraoperative assessment of anastomotic perfusion. STUDY DESIGN: This is a prospective, multicenter, open-label, clinical trial that assessed the feasibility and utility of FA for intraoperative perfusion assessment during left-sided colectomy and anterior resection at 11 centers in the United States. RESULTS: A total of 147 patients were enrolled, of whom 139 were eligible for analysis. Diverticulitis (44%), rectal cancer (25%), and colon cancer (21%) were the most prevalent indications for surgery. The mean level of anastomosis was 10 ± 4 cm from the anal verge. Splenic-flexure mobilization was performed in 81% and high ligation of the inferior mesenteric artery in 61.9% of patients. There was a 99% success rate for FA, and FA changed surgical plans in 11 (8%) patients, with the majority of changes occurring at the time of transection of the proximal margin (7%). Overall morbidity rates were 17%. The anastomotic leak rate was 1.4% (n = 2). There were no anastomotic leaks in the 11 patients who had a change in surgical plan based on intraoperative perfusion assessment with FA. CONCLUSIONS: PINPOINT is a safe and feasible tool for intraoperative assessment of tissue perfusion during colorectal resection. There were no anastomotic leaks in patients in whom the anastomosis was revised based on inadequate perfusion with FA.