Risk prediction algorithms for prolonged postoperative ileus: A systematic review.

AIM: Prolonged postoperative ileus (PPOI) is common and is associated with a significant healthcare burden. Previous studies have attempted to predict PPOI clinically using risk prediction algorithms. The aim of this work was to systematically review and compare risk prediction algorithms for PPOI following colorectal surgery. METHOD: A systematic literature search was conducted using MEDLINE, Embase, Web of Science and CINAHL Plus. Studies that developed and/or validated a risk prediction algorithm for PPOI in adults following colorectal surgery were included. Data were collected on study design, population and operative characteristics, the definition of PPOI used and risk prediction algorithm design and performance. Quality appraisal was assessed using the PROBAST tool. RESULTS: Eleven studies with 87 549 participants were included in our review. Most were retrospective, single-centre analyses (6/11, 55%) and rates of PPOI varied from 10% to 28%. The most commonly used variables were sex (8/11, 73%), age (6/11, 55%) and surgical approach (5/11, 45%). Area under the curve ranged from 0.68-0.78, and only three models were validated. However, there was significant variation in the definition of PPOI used. No study reported sensitivity, specificity or positive/negative predictive values. CONCLUSION: Currently available risk prediction algorithms for PPOI appear to discriminate moderately well, although there is a lack of validation data. Future studies should aim to use a standardized definition of PPOI, comprehensively report model performance and validate their findings using internal and external methodologies.

Variation in the definition of 'failure to rescue' from postoperative complications: a systematic review and recommendations for outcome reporting.

BACKGROUND: Failure to rescue is the rate of death amongst patients with postoperative complications and has been proposed as a perioperative quality indicator. However, variation in its definition has limited comparisons between studies. We systematically reviewed all surgical literature reporting failure to rescue rates and examined variations in the definition of the 'numerator,' 'denominator,' and timing of failure to rescue measurement. METHODS: Databases were searched from inception to 31 December 2022. All studies reporting postoperative failure to rescue rates as a primary or secondary outcome were included. We examined the complications included in the failure to rescue denominator, the percentage of deaths captured by the failure to rescue numerator, and the timing of measurement for complications and mortality. RESULTS: A total of 359 studies, including 212,048,069 patients, were analyzed. The complications included in the failure to rescue denominator were reported in 295 studies (82%), with 131 different complications used. The median number of included complications per study was 10 (interquartile range 8-15). Studies that included a higher number of complications in the failure-to-rescue denominator reported lower failure-to-rescue rates. Death was included as a complication in the failure to rescue the denominator in 65 studies (18%). The median percentage of deaths captured by the failure to rescue calculation when deaths were not included in the denominator was 79%. Complications (52%) and mortality (40%) were mostly measured in-hospital, followed by 30-days after surgery. CONCLUSION: Failure to rescue is an important concept in the study of postoperative outcomes, although its definition is highly variable and poorly reported. Researchers should be aware of the advantages and disadvantages of different approaches to defining failure to rescue.

Clinical utility of trans-sacral magnetic stimulation-evoked sphincter potentials and high-density electromyography in pelvic floor assessment: Technical evaluation.

AIM: Faecal incontinence is common and of multifactorial aetiologies, yet current diagnostic tools are unable to assess nerve and sphincter function objectively. We developed an anorectal high-density electromyography (HD-EMG) probe to evaluate motor-evoked potentials induced via trans-sacral magnetic stimulation (TSMS). METHOD: Anorectal probes with an 8 × 8 array of electrodes spaced 1 cm apart were developed for recording HD-EMG of the external anal sphincter. These HD-EMG probes were used to map MEP amplitudes and latencies evoked via TSMS delivered through the Magstim Rapid2 (MagStim Company). Patients undergoing pelvic floor investigations were recruited for this IDEAL Stage 2a pilot study. RESULTS: Eight participants (median age 49 years; five female) were recruited. Methodological viability, safety and diagnostic workflow were established. The test was well tolerated with median discomfort scores ≤2.5/10, median pain scores ≤1/10 and no adverse events. Higher Faecal Incontinence Severity Index scores correlated with longer MEP latencies (r = 0.58, p < 0.001) and lower MEP amplitudes (r = -0.32, p = 0.046), as did St. Mark's Incontinence Scores with both MEP latencies (r = 0.49, p = 0.001) and MEP amplitudes (r = -0.47, p = 0.002). CONCLUSION: This HD-EMG probe in conjunction with TSMS presents a novel diagnostic tool for anorectal function assessment. Spatiotemporal assessment of magnetically stimulated MEPs correlated well with symptoms and offers a feasible, safe and patient-tolerable method of evaluating pudendal nerve and external anal sphincter function. Further clinical development and evaluation of these techniques is justified.

The influence of defaecating proctograms on clinical decision-making in pelvic floor disorders.

AIM: Defaecating proctogram (DP) studies have become an integral part of the evaluation of patients with pelvic floor disorders. However, their impact on treatment decision-making remains unclear. The aim of this study was to assess the concordance of decision-making by colorectal surgeons and the role of the DP in this process. METHOD: Four colorectal surgeons were presented with online surveys containing the complete history, examination and investigations of 106 de-identified pelvic floor patients who had received one of three treatment options: physiotherapy only, anterior Delorme's procedure or anterior mesh rectopexy. The survey assessed the management decisions made by each of the surgeons for the three treatments both before and after the addition of the DP to the diagnostic work-up. RESULTS: After the addition of the DP results; treatment choice changed in 219 (52%) of 424 surgical decisions and interrater agreement improved significantly from κ = 0.26 to κ = 0.39. Three of the four surgeons reported a significant increase in confidence. Agreement with the actual treatments patients received increased from κ = 0.21 to κ = 0.28. Intra-anal rectal prolapse on DP was a significant predictor of a decision to perform anterior mesh rectopexy. CONCLUSION: The DP improves interclinician agreement in the management of pelvic floor disorders and enhances the confidence in treatment decisions. Intra-anal rectal prolapse was the most influential DP parameter in treatment decision-making.

The impact of delay and prehospital factors on acute appendicitis severity in New Zealand children: a national prospective cohort study.

BACKGROUND: Appendicitis is the most common reason children undergo acute general surgery but international, population-level disparities exist. This is hypothesised to be caused by preoperative delay and differential access to surgical care. The impact of prehospital factors on paediatric appendicitis severity in New Zealand is unknown. METHODS: A prospective, multicentre cohort study with nested parental questionnaire was conducted by a national trainee-led collaborative group. Across 14 participating hospitals, 264 patients aged ≤16 years admitted between January and June 2020 with suspected appendicitis were screened. The primary outcome was the effect of prehospital factors on the American Association for the Surgery of Trauma (AAST) anatomical severity grade. RESULTS: Overall, 182 children had confirmed appendicitis with a median age of 11.6. The rate of complicated appendicitis rate was 38.5% but was significantly higher in rural (44.1%) and Maori children (54.8%). Complicated appendicitis was associated with increased prehospital delay (47.8 h versus 20.1 h; P < 0.001), but not in-hospital delay (11.3 h versus 13.3 h; P = 0.96). Multivariate analysis revealed increased anatomical severity in rural (OR 4.33, 95% CI 1.78-7.25; P < 0.001), and Maori children (OR 2.39, 95% CI 1.24-5.75; P = 0.019), as well as in families relying on external travel sources or reporting unfamiliarity with appendicitis symptomology. CONCLUSION: Prehospital delay and differential access to prehospital determinants of health are associated with increased severity of paediatric appendicitis. This manifested as increased severity of appendicitis in rural and Maori children. Understanding the pre-hospital factors that influence the timing of presentation can better inform health-system improvements.

Seasonal variations in acute diverticular disease hospitalisations in New Zealand.

PURPOSE: Seasonal variation of acute diverticular disease is variably reported in observational studies. This study aimed to describe seasonal variation of acute diverticular disease hospital admissions in New Zealand. METHODS: A time series analysis of national diverticular disease hospitalisations from 2000 to 2015 was conducted among adults aged 30 years or over. Monthly counts of acute hospitalisations' primary diagnosis of diverticular disease were decomposed using Census X-11 times series methods. A combined test for the presence of identifiable seasonality was used to determine if overall seasonality was present; thereafter, annual seasonal amplitude was calculated. The mean seasonal amplitude of demographic groups was compared by analysis of variance. RESULTS: Over the 16-year period, 35,582 hospital admissions with acute diverticular disease were included. Seasonality in monthly acute diverticular disease admissions was identified. The mean monthly seasonal component of acute diverticular disease admissions peaked in early-autumn (March) and troughed in early-spring (September). The mean annual seasonal amplitude was 23%, suggesting on average 23% higher acute diverticular disease hospitalisations during early-autumn (March) than in early-spring (September). The results were similar in sensitivity analyses that employed different definitions of diverticular disease. Seasonal variation was less pronounced in patients aged over 80 (p = 0.002). Seasonal variation was significantly greater among Maori than Europeans (p < 0.001) and in more southern regions (p < 0.001). However, seasonal variations were not significantly different by gender. CONCLUSIONS: Acute diverticular disease admissions in New Zealand exhibit seasonal variation with a peak in Autumn (March) and a trough in Spring (September). Significant seasonal variations are associated with ethnicity, age, and region, but not with gender.

Characterising nationwide reasons for unplanned hospital readmission after colorectal cancer surgery.

BACKGROUND: Readmissions after colorectal cancer surgery are common, despite advancements in surgical care, and have a significant impact on both individual patients and overall healthcare costs. The aim of this study was to determine the 30-and 90 days readmission rate after colorectal cancer surgery, and to investigate the risk factors and clinical reasons for unplanned readmissions. METHOD: A multicenter, population-based study including all patients discharged after index colorectal cancer resection from 2010 to 2020 in Aotearoa New Zealand (AoNZ) was completed. The Ministry of Health National Minimum Dataset was used. Rates of readmission at 30 days and 90 days were calculated. Mixed-effect logistic regression models were built to investigate factors associated with unplanned readmission. Reasons for readmission were described. RESULTS: Data were obtained on 16,885 patients. Unplanned 30-day and 90-day hospital readmission rates were 15.1% and 23.7% respectively. The main readmission risk factors were comorbidities, advanced disease, and postoperative complications. Hospital level variation was not present. Despite risk adjustment, R2 value of models was low (30 days: 4.3%, 90 days: 5.2%). The most common reasons for readmission were gastrointestinal causes (32.1%) and wound complications (14.4%). Rates of readmission did not improve over the 11 years study period (p = 0.876). CONCLUSION: Readmissions following colorectal resections in AoNZ are higher than other comparable healthcare systems and rates have remained constant over time. While patient comorbidities and postoperative complications are associated with readmission, the explanatory value of these variables is poor. To reduce unplanned readmissions, efforts should be focused on prevention and early detection of post-discharge complications.

"Failure to Rescue" following Colorectal Cancer Resection: Variation and Improvements in a National Study of Postoperative Mortality.

OBJECTIVE: To examine variation in "failure to rescue" (FTR) as a driver of differences in mortality between centres and over time for patients undergoing colorectal cancer surgery. BACKGROUND: Wide variation exists in postoperative mortality following colorectal cancer surgery. FTR has been identified as an important determinant of variation in postoperative outcomes. We hypothesized that differences in mortality both between hospitals and over time are driven by variation in FTR. METHODS: A national population-based study of patients undergoing colorectal cancer resection from 2010 to 2019 in Aotearoa New Zealand was conducted. Rates of 90-day FTR, mortality, and complications were calculated overall, and for surgical and nonoperative complications. Twenty District Health Boards (DHBs) were ranked into quartiles using risk- and reliability-adjusted 90-day mortality rates. Variation between DHBs and trends over the 10-year period were examined. RESULTS: Overall, 15,686 patients undergoing resection for colorectal adenocarcinoma were included. Increased postoperative mortality at high-mortality centers (OR 2.4, 95% CI 1.8-3.3) was driven by higher rates of FTR (OR 2.0, 95% CI 1.5-2.8), and postoperative complications (OR 1.4, 95% CI 1.3-1.6). These trends were consistent across operative and nonoperative complications. Over the 2010 to 2019 period, postoperative mortality halved (OR 0.5, 95% CI 0.4-0.6), associated with a greater improvement in FTR (OR 0.5, 95% CI 0.4-0.7) than complications (OR 0.8, 95% CI 0.8-0.9). Differences between centers and over time remained when only analyzing patients undergoing elective surgery. CONCLUSION: Mortality following colorectal cancer resection has halved over the past decade, predominantly driven by improvements in "rescue" from complications. Differences in FTR also drive hospital-level variation in mortality, highlighting the central importance of "rescue" as a target for surgical quality improvement.

Hyperactive Distal Colonic Motility and Recovery Patterns Following Right Colectomy: A High-Resolution Manometry Study.

BACKGROUND: Postoperative ileus results in morbidity, prolonged hospitalization, and increased health care expenditure. However, the underlying abnormalities in motility remain poorly understood. Recent high-resolution manometry studies demonstrated that the distal colon becomes hyperactive with a cyclic motor pattern postoperatively, but they did not track this activity beyond 16 hours after surgery. OBJECTIVE: This study used high-resolution manometry to evaluate distal colonic motility during the first 4 days after right-sided colectomy. DESIGN: An observational study of perioperative high-resolution colonic manometry using a 36-sensor catheter with 1-cm resolution. SETTING: A single tertiary hospital. PATIENTS: Adult patients undergoing elective laparoscopic or open right-sided colonic resection. MAIN OUTCOME MEASURES: Occurrence of distal colonic motor patterns during the perioperative period, defined according to a published classification system. Clinical markers of gut recovery included time to first stool, oral diet, and prolonged postoperative ileus. RESULTS: Seven patients underwent perioperative manometry recordings. Hyperactive cyclic motor patterns emerged intraoperatively and peaked in the first 12 hours postoperatively, occupying 81.8% ± 3.9% of the recording. This gradually returned to normal during the first 4 days, reaching 19.0% ± 4.4% ( p = 0.002). No patient had a bowel movement before this hyperactivity resolved. High-amplitude propagating sequences were absent in early postoperative recordings, and their return temporally correlated with the passage of stool. Abnormal high-amplitude repetitive 0.5 to 1 cycle per minute activity was observed in the left colon of 1 patient with prolonged ileus. LIMITATIONS: The invasive nature of recordings limited this study to a small sample size. CONCLUSIONS: Cyclic motor patterns are markedly hyperactive in the distal colon after right-sided colectomy and resolve during the first 4 postoperative days. High-amplitude propagating sequences are inhibited by surgery and gradually recover. Bowel function may not return until these changes resolve. Other abnormal repetitive hyperactive patterns could contribute to the development of prolonged ileus. See Video Abstract at http://links.lww.com/DCR/B967 . MOTILIDAD HIPERACTIVA DEL COLON DISTAL Y PATRONES DE RECUPERACIN DESPUS DE COLECTOMA DERECHA UN ESTUDIO DE MANOMETRA DE ALTA RESOLUCIN: ANTECEDENTES:El íleo post-operatorio produce una morbilidad significativa, una hospitalización prolongada y un aumento del gasto sanitario. Sin embargo, las anomalías subyacentes en la motilidad siguen siendo poco conocidas. Estudios recientes de manometría de alta resolución demostraron que el colon distal se vuelve hiperactivo con un patrón motor cíclico en el post-operatorio, pero no registraron esta actividad más allá de las 16 horas posteriores a la cirugía.OBJETIVO:Utilizar la manometría de alta resolución para evaluar la motilidad del colon distal durante los primeros cuatro días después de la colectomía del lado derecho.DISEÑO:Estudio observacional de pacientes sometidos a manometría colónica perioperatoria de alta resolución mediante catéter de 36 sensores con 1 cm de resolución.AJUSTE:Un solo hospital terciario.PACIENTES:Pacientes adultos sometidos a resección laparoscópica o abierta de colon del lado derecho de forma electiva.PRINCIPALES MEDIDAS DE RESULTADO:AAparición de patrones motores del colon distal durante el período perioperatorio, definidos según un sistema de clasificación publicado. Los marcadores clínicos de recuperación intestinal incluyeron, tiempo hasta la primera evacuación, dieta oral e íleo posoperatorio prolongado.RESULTADOS:Siete pacientes fueron sometidos a registros de manometría perioperatoria. Los patrones motores cíclicos hiperactivos emergieron intraoperatoriamente y alcanzaron su punto máximo en las primeras 12 horas post-operatorias, ocupando 81,8 ± 3,9% del registro. Esto volvió gradualmente a la normalidad durante los primeros cuatro días, alcanzando el 19,0 ± 4,4% (p = 0,002). Ningún paciente tuvo una evacuación intestinal antes de que se resolviera esta hiperactividad. Las secuencias de propagación de alta amplitud estaban ausentes en las grabaciones post-operatorias tempranas y su retorno se correlacionó temporalmente con el paso de las heces. Se observó actividad anormal de alta amplitud repetitiva de 0,5-1 ciclo / minuto en el colon izquierdo de un paciente con íleo prolongado.LIMITACIONES:La naturaleza invasiva de las grabaciones limitó este estudio a un tamaño de muestra pequeño.CONCLUSIONES:Los patrones motores cíclicos son marcadamente hiperactivos en el colon distal después de la colectomía del lado derecho y se resuelven gradualmente durante los primeros cuatro días posoperatorios. Las secuencias de propagación de gran amplitud se inhiben mediante cirugía y se recuperan gradualmente. Es posible que la función intestinal no regrese hasta que estos cambios se resuelvan. Otros patrones hiperactivos repetitivos anormales podrían contribuir al desarrollo de íleo prolongado. Consulte Video Resumen en http://links.lww.com/DCR/B967 . (Traducción-Dr. Mauricio Santamaria ).

The role of colonic motility in low anterior resection syndrome.

Low anterior resection syndrome (LARS) describes the symptoms and experiences of bowel dysfunction experienced by patients after rectal cancer surgery. LARS is a complex and multifactorial syndrome exacerbated by factors such as low anastomotic height, defunctioning of the colon and neorectum, and radiotherapy. There has recently been growing awareness and understanding regarding the role of colonic motility as a contributing mechanism for LARS. It is well established that rectosigmoid motility serves an important role in coordinating rectal filling and maintaining continence. Resection of the rectosigmoid may therefore contribute to LARS through altered distal colonic and neorectal motility. This review evaluates the role of colonic motility within the broader pathophysiology of LARS and outlines future directions of research needed to enable targeted therapy for specific LARS phenotypes.

Faecal incontinence is associated with an impaired rectosigmoid brake and improved by sacral neuromodulation.

BACKGROUND: The rectosigmoid brake, characterised by retrograde cyclic motor patterns on high-resolution colonic manometry, has been postulated as a contributor to the maintenance of bowel continence. Sacral neuromodulation (SNM) is an effective therapy for faecal incontinence, but its mechanism of action is unclear. This study aims to investigate the colonic motility patterns in the distal colon of patients with faecal incontinence, and how these are modulated by SNM. METHODS: A high-resolution fibreoptic colonic manometry catheter, containing 36 sensors spaced at 1-cm intervals, was positioned in patients with faecal incontinence undergoing stage 1 SNM. One hour of pre- and post meal recordings were obtained followed by pre- and post meal recordings with suprasensory SNM. A 700-kcal meal was given. Data were analysed to identify propagating contractions. RESULTS: Fifteen patients with faecal incontinence were analysed. Patients had an abnormal meal response (fewer retrograde propagating contractions compared to controls; p = 0.027) and failed to show a post meal increase in propagating contractions (mean 17 ± 6/h premeal vs. 22 ± 9/h post meal, p = 0.438). Compared to baseline, SNM significantly increased the number of retrograde propagating contractions in the distal colon (8 ± 3/h premeal vs. 14 ± 3/h premeal with SNM, p = 0.028). Consuming a meal did not further increase the number of propagating contractions beyond the baseline upregulating effect of SNM. CONCLUSION: The rectosigmoid brake was suppressed in this cohort of patients with faecal incontinence. SNM may exert a therapeutic effect by modulating this rectosigmoid brake.

Wearable devices to monitor recovery after abdominal surgery: scoping review.

BACKGROUND: Wearable devices have been proposed as a novel method for monitoring patients after surgery to track recovery, identify complications early, and improve surgical safety. Previous studies have used a heterogeneous range of devices, methods, and analyses. This review aimed to examine current methods and wearable devices used for monitoring after abdominal surgery and identify knowledge gaps requiring further investigation. METHODS: A scoping review was conducted given the heterogeneous nature of the evidence. MEDLINE, EMBASE, and Scopus databases were systematically searched. Studies of wearable devices for monitoring of adult patients within 30 days after abdominal surgery were eligible for inclusion. RESULTS: A total of 78 articles from 65 study cohorts, with 5153 patients were included. Thirty-one different wearable devices were used to measure vital signs, physiological measurements, or physical activity. The duration of postoperative wearable device use ranged from 15 h to 3 months after surgery. Studies mostly focused on physical activity metrics (71.8 per cent). Continuous vital sign measurement and physical activity tracking both showed promise for detecting postoperative complications earlier than usual care, but conclusions were limited by poor device precision, adherence, occurrence of false alarms, data transmission problems, and retrospective data analysis. Devices were generally well accepted by patients, with high levels of acceptance, comfort, and safety. CONCLUSION: Wearable technology has not yet realized its potential to improve postoperative monitoring. Further work is needed to overcome technical limitations, improve precision, and reduce false alarms. Prospective assessment of efficacy, using an intention-to-treat approach should be the focus of further studies.

The Longitudinal Course of Low-anterior Resection Syndrome: An individual Patient Meta-analysis.

OBJECTIVE: We aimed to better understand the longitudinal course of low anterior resection syndrome (LARS) to guide patient expectations and identify those at risk of persisting dysfunction. SUMMARY BACKGROUND DATA: LARS describes disordered bowel function after rectal resection that significantly impacts quality of life. METHODS: MEDLINE, EMBASE, CENTRAL, and CINAHL databases were systematically searched for studies that enrolled adults undergoing anterior resection for rectal cancer and used the LARS score to assess bowel function at ≥2 postoperative time points. Regression analyses were performed on deidentified patient-level data to identify predictors of change in LARS score from baseline (3-6months) to 12-months and 18-24 months. RESULTS: Eight studies with a total of 701 eligible patients were included. The mean LARS score improved over time, from 29.4 (95% confidence interval 28.6-30.1) at baseline to 16.6 at 36 months (95% confidence interval 14.2%-18.9%). On multivariable analysis, a greater improvement in mean LARS score between baseline and 12 months was associated with no ileostomy formation [mean difference (MD) -1.7 vs 1.7, P < 0.001], and presence of LARS (major vs minor vs no LARS) at baseline (MD -3.8 vs -1.7 vs 5.4, P < 0.001). Greater improvement in mean LARS score between baseline and 18-24 months was associated with partial mesorectal excision vs total mesorectal excision (MD-8.6 vs 1.5, P < 0.001) and presence of LARS (major vs minor vs no LARS) at baseline (MD -8.8 vs -5.3 vs 3.4, P < 0.001). CONCLUSIONS: LARS improves by 18 months postoperatively then remains stable for up to 3 years. Total mesorectal excision, neoadjuvant radiotherapy, and ileostomy formation negatively impact upon bowel function recovery.

Detection of Anastomotic Leakage Following Elective Colonic Surgery: Results of the Prospective Biomarkers and Anastomotic Leakage (BALL) Study.

BACKGROUND: Anastomotic leakage (AL) is an infrequent but life-threatening surgical complication following colorectal surgery. Early diagnosis remains clinically difficult but is a necessity to reduce associated morbidity and mortality. Clinical review and radiological modalities for the diagnosis of leakage remain non-specific and often only detect AL once it is well developed. Inflammatory biomarkers however have shown promise in early pre-clinical detection of leakage following colorectal surgery. METHODS: A multi-center, prospective observational study was conducted across four public hospitals in Auckland and Christchurch, New Zealand. Consecutive adults undergoing elective colectomy were initially recruited over a 3-y period. Perioperative blood samples were collected to measure interleukin (IL)-6, IL-1ß, tumor necrosis factor α, IL-10, C-reactive protein (CRP), leukocyte and neutrophil counts. Statistical analysis was performed to compare patients with an uncomplicated recovery with patients with AL. RESULTS: Sixteen patients developed AL (5.7%), diagnosed at a median post-operative (POD) day 7. CRP and IL-6 were consistently elevated in the early post-operative period in patients with AL, and had the best diagnostic accuracy on POD 3 (area under the curve 0.70; P = 0.02) and POD 1 (area under the curve 0.69; P = 0.02), respectively. IL-10, once adjusted for body mass index and surgical approach, was the sole biomarker significantly elevated in patients with AL on POD 4. CONCLUSIONS: Early post-operative elevations of CRP and IL-6 provide utility for early detection of AL after elective colectomy. Application of these inflammatory biomarkers and their combinations in daily practice warrants further investigation.

Post-operative ileus: definitions, mechanisms and controversies.

Post-operative ileus (POI) is a syndrome of impaired gastrointestinal transit which occurs following abdominal surgery. There are few effective targeted therapies for ileus, and research has been limited by inconsistent definitions and an incomplete understanding of the underlying pathophysiology. Despite considerable effort, there remains no widely-adopted definition of ileus, and recent work has identified variation in outcome reporting is a major source of heterogeneity in clinical trials. Outcomes should be clearly-defined, clinically-relevant, and reflective of the underlying biology, impacts on hospital resources and quality of life. Further collaborative efforts will be needed to develop consensus definitions and a core outcome set for postoperative gastrointestinal recovery. Investigation into the pathophysiology of POI has been hindered by use of low-resolution techniques and difficulties linking cellular mechanisms to dysmotility patterns and clinical symptoms. Recent evidence has suggested the common assumption of post-operative GI paralysis is incorrect, and that the distal colon becomes hyperactive following surgery. The post-operative inflammatory response is important in the pathophysiology of ileus, but the time course of this in humans remains unclear, with the majority of evidence coming from animal models. Future work should investigate dysmotility patterns underlying ileus, and identify biomarkers which may be used to diagnose, monitor and stratify patients with ileus.

Functional Outcome of Laparoscopic-Assisted Resection Versus Open Resection of Rectal Cancer: A Secondary Analysis of the Australasian Laparoscopic Cancer of the Rectum Trial.

BACKGROUND: Low anterior resection syndrome has a significant impact on the quality of life in rectal cancer survivors. Previous studies comparing laparoscopic to open rectal resection have neglected bowel function outcomes. OBJECTIVE: This study aimed to assess whether there is a difference in the functional outcome between patients undergoing laparoscopic versus open resection for rectal adenocarcinoma. DESIGN: Cross-sectional prevalence of low anterior resection syndrome was assessed in a secondary analysis of the multicenter phase 3 randomized clinical trial, Australasian Laparoscopic Cancer of the Rectum Trial (ACTRN12609000663257). SETTING: There were 7 study subsites across New Zealand and Australia. PATIENTS: Participants were adults with rectal cancer who underwent anterior resection and had bowel continuity. MAIN OUTCOME MEASURES: Postoperative bowel function was evaluated using the validated low anterior resection syndrome score and Bowel Function Instrument. RESULTS: The Australasian Laparoscopic Cancer of the Rectum Trial randomized 475 patients with T1-T3 rectal adenocarcinoma less than 15 cm from the anal verge. A total of 257 participants were eligible for, and invited to, participate in additional follow-up; 163 (63%) completed functional follow-up. Overall cross-sectional prevalence of major low anterior resection syndrome was 49% (minor low anterior resection syndrome 27%). There were no differences in median overall Bowel Function Instrument score nor low anterior resection syndrome score between participants undergoing laparoscopic versus open surgery (66 vs 67, p = 0.52; 31 vs 27, p = 0.24) at a median follow-up of 69 months. LIMITATIONS: The major limitations are a result of conducting a secondary analysis; the likelihood of an insufficient sample size to detect a difference in prevalence between the groups and the possibility of selection bias as a subset of the randomized population was analyzed. CONCLUSIONS: Bowel dysfunction affects a majority of rectal cancer patients for a significant time after the operation. In this secondary analysis of a randomized trial, surgical approach does not appear to influence the likelihood or severity of low anterior resection syndrome. See Video Abstract at http://links.lww.com/DCR/B794. RESULTADO FUNCIONAL DE LA RESECCIN ASISTIDA POR LAPAROSCOPIA VERSUS RESECCIN ABIERTA EN CNCER DE RECTO ANLISIS SECUNDARIO DEL ESTUDIO DE CNCER DE RECTO LAPAROSCPICO DE AUSTRALASIA: ANTECEDENTES:El síndrome de resección anterior baja tiene un impacto significativo en la calidad de vida de los supervivientes de cáncer de recto. Los estudios anteriores que compararon la resección rectal laparoscópica con la abierta no han presentado resultados de la función intestinal.OBJETIVO:Evaluar si existe una diferencia en el resultado funcional entre los pacientes sometidos a resección laparoscópica versus resección abierta por adenocarcinoma de recto.DISEÑO:La prevalencia transversal del síndrome de resección anterior baja se evaluó en un análisis secundario del ensayo clínico aleatorizado multicéntrico de fase 3, Estudio Sobre el Cáncer de Recto Laparoscópico de Australasia (Australasian Laparoscopic Cancer of the Rectum Trial, ACTRN12609000663257).AJUSTE:Siete subsitios de estudio en Nueva Zelanda y Australia.PACIENTES:Los participantes eran adultos con cáncer de recto que se sometieron a resección anterior con anastomosis.PRINCIPALES MEDIDAS DE RESULTADO:La función intestinal posoperatoria se evaluó utilizando el previamente validado puntaje LARS y el Instrumento de Función Intestinal.RESULTADOS:El Estudio Sobre el Cáncer de Recto Laparoscópico de Australasia asignó al azar a 475 pacientes con adenocarcinoma rectal T1-T3 a menos de 15 cm del borde anal. 257 participantes fueron elegibles e invitados a participar en un seguimiento adicional. 163 (63%) completaron el seguimiento funcional. La prevalencia transversal general de LARS mayor fue del 49% (LARS menor 27%). No hubo diferencias en la puntuación media general del Instrumento de Función Intestinal ni en la puntuación LARS entre los participantes sometidos a cirugía laparoscópica versus cirugía abierta (66 frente a 67, p = 0,52; 31 frente a 27, p = 0,24) en una mediana de seguimiento de 69 meses.LIMITACIONES:Las principales limitaciones son el resultado de realizar un análisis secundario; se analizó la probabilidad de un tamaño de muestra insuficiente para detectar una diferencia en la prevalencia entre los grupos y la posibilidad de sesgo de selección como un subconjunto de la población aleatorizada.CONCLUSIONES:La disfunción intestinal afecta a la mayoría de los pacientes con cáncer de recto durante un tiempo significativo después de la operación. En este análisis secundario de un ensayo aleatorizado, el abordaje quirúrgico no parece influir en la probabilidad o gravedad del síndrome de resección anterior baja. Consulte Video Resumen en http://links.lww.com/DCR/B794. (Traducción-Dr. Felipe Bellolio).

Potential causes of the preoperative increase in the rectosigmoid cyclic motor pattern: A high-resolution manometry study.

BACKGROUND: Cyclic motor patterns (CMPs) are the most common motor pattern in the distal colon. This study used high-resolution (HR) colonic manometry to quantify trends in distal colonic motor activity before elective colonic surgery, determine the effect of a preoperative carbohydrate load, and compare this with a meal response in healthy controls. METHODS: Fiber-optic HR colonic manometry (36 sensors, 1 cm intervals) was used to investigate distal colonic motor activity in 10 adult patients prior to elective colonic surgery, 6 of whom consumed a preoperative carbohydrate drink (200 kCal). Data were compared with nine healthy volunteers who underwent HR colonic manometry recordings while fasted and following a 700 kCal meal. The primary outcome was the percentage of recording occupied by CMPs, defined as propagating contractions at 2-4 cycles per minute (cpm). Secondary outcomes included amplitude, speed, and distance of propagating motor patterns. RESULTS: The occurrence of CMPs progressively increased in time periods closer to surgery (p = 0.001). Consumption of a preoperative drink resulted in significantly increased CMP occurrence (p = 0.04) and propagating distance (p = 0.04). There were no changes in amplitude or speed of propagating motor patterns during the preoperative period. The increase in activity following a preoperative drink was of similar magnitude to the colonic meal response observed in healthy controls, despite the lesser caloric nutrient load. CONCLUSION: Distal colonic CMP increased in occurrence prior to surgery, amplified by ingestion of preoperative carbohydrate drinks. We hypothesize that anxiety, which is also known to rise with proximity to surgery, could play a contributing role.