Global cost of postoperative ileus following abdominal surgery: meta-analysis

Published: 23 June 2023Background: Following abdominal surgery, postoperative ileus is a common complication significantly increasing patient morbidity and cost of hospital admission. This is the first systematic review aimed at determining the average global hospital cost per patient associated with postoperative ileus. Methods: A systematic search of electronic databases was performed from January 2000 to March 2023. Studies included compared patients undergoing abdominal surgery who developed postoperative ileus to those who did not, focusing on costing data. The primary outcome was the total cost of inpatient stay. Risk of bias was assessed using the Newcastle–Ottawa assessment tool. Summary meta-analysis was performed. Results: Of the 2071 studies identified, 88 papers were assessed for full eligibility. The systematic review included nine studies (2005– 2022), investigating 1 860 889 patients undergoing general, colorectal, gynaecological and urological surgery. These studies showed significant variations in the definition of postoperative ileus. Six studies were eligible for meta-analysis showing an increase of €8233 (95 per cent c.i. (5176 to 11 290), P < 0.0001, I² = 95.5 per cent) per patient with postoperative ileus resulting in a 66.3 per cent increase in total hospital costs (95 per cent c.i. (34.8 to 97.9), P < 0.0001, I² = 98.4 per cent). However, there was significant bias between studies. Five colorectal-surgery-specific studies showed an increase of €7242 (95 per cent c.i. (4502 to 9983), P < 0.0001, I² = 86.0 per cent) per patient with postoperative ileus resulting in a 57.3 per cent increase in total hospital costs (95 per cent c.i. (36.3 to 78.3), P < 0.0001, I² = 85.7 per cent). Conclusion: The global financial burden of postoperative ileus following abdominal surgery is significant. While further multicentre data using a uniform postoperative ileus definition would be useful, reducing the incidence and impact of postoperative ileus are a priority to mitigate healthcare-related costs, and improve patient outcomes.Luke Traeger, Michalis Koullouros, Sergei Bedrikovetski, Hidde M. Kroon, James W. Moore and Tarik Sammou

Regional variance in treatment and outcomes of locally invasive (T4) rectal cancer in Australia and New Zealand: analysis of the Bi-National Colorectal Cancer Audit

BACKGROUNDS: Locally invasive T4 rectal cancer often requires neoadjuvant treatment followed by multi-visceral surgery to achieve a radical resection (R0), and referral to a specialized exenteration quaternary centre is typically recommended. The aim of this study was to explore regional variance in treatment and outcomes of patients with locally advanced rectal cancer in Australia and New Zealand (ANZ). METHODS: Data were collected from the Bi-National Colorectal Cancer Audit (BCCA) database. Rectal cancer patients treated between 2007 and 2019 were divided into six groups based on region (state/country) using patient postcode. A subset analysis of patients with T4 cancer was performed. Primary outcomes were positive circumferential resection margin (CRM+), and positive circumferential and/or distal resection margin (CRM/DRM+). RESULTS: A total of 9385 patients with rectal cancer were identified, with an overall CRM+ rate of 6.4% and CRM/DRM+ rate of 8.6%. There were 1350 patients with T4 rectal cancer (14.4%). For these patients, CRM+ rate was 18.5%, and CRM/DRM+ rate was 24.1%. Significant regional variation in CRM+ (range 13.4-26.0%; p = 0.025) and CRM/DRM+ rates (range 16.1-29.3%; p = 0.005) was identified. In addition, regions with higher CRM+ and CRM/DRM+ rates reported lower rates of multi-visceral resections: range 24.3-26.8%, versus 32.6-37.3% for regions with lower CRM+ and CRM/DRM+ rates (p < 0.0001). CONCLUSION: Positive resection margins and rates of multi-visceral resection vary between the different regions of ANZ. A small subset of patients with T4 rectal cancer are particularly at risk, further supporting the concept of referral to specialized exenteration centres for potentially curative multi-visceral resection.Tessa L. Dinger, Hidde M. Kroon, Luke Traeger, Sergei Bedrikovetski, Andrew Hunter and Tarik Sammou

Cost of postoperative ileus following colorectal surgery: a cost analysis in the Australian public hospital setting

Aim: Postoperative ileus (POI) following surgery results in significant morbidity, drastically increasing hospital costs. As there are no specific Australian data, this study aimed to measure the cost of POI after colorectal surgery in an Australian public hospital. Methods: A cost analysis was performed, for major elective colorectal surgical cases between 2018 and 2021 at the Royal Adelaide Hospital. POI was defined as not achieving GI-2, the validated composite measure, by postoperative day 4. Demographics, length of stay and 30-day complications were recorded retrospectively. Costings in Australian dollars were collected from comprehensive hospital billing data. Univariate and multivariate analyses were performed. Results: Of the 415 patients included, 34.9% (n = 145) developed POI. POI was more prevalent in males, smokers, previous intra-abdominal surgery, and converted laparoscopic surgery (p < 0.05). POI was associated with increased length of stay (8 vs. 5 days, p < 0.001) and with higher rates of complications such as pneumonia (15.2% vs. 8.1%, p = 0.027). Total cost of inpatient care was 26.4% higher after POI (AU$37,690 vs. AU$29,822, p < 0.001). POI was associated with increased staffing costs, as well as diagnostics, pharmacy, and hospital services. On multivariate analysis POI, elderly patients, stoma formation, large bowel surgery, prolonged theatre time, complications and length of stay were predictive of increased costs (p < 0.05). Conclusion: In Australia, POI is significantly associated with increased complications and higher costs due to prolonged hospital stay and increased healthcare resource utilisation. Efforts to reduce POI rates could diminish its morbidity and associated expenses, decreasing the burden on the healthcare system.Luke Traeger, Michalis Koullouros, Sergei Bedrikovetski, Hidde M. Kroon, Michelle L. Thomas, James W. Moore, Tarik Sammou

Safety and efficacy of laxatives after major abdominal surgery: systematic review and meta-analysis

Background: Recovery of gastrointestinal function is often delayed after major abdominal surgery, leading to postoperative ileus (POI). Enhanced recovery protocols recommend laxatives to reduce the duration of POI, but evidence is unclear. This systematic review aimed to assess the safety and efficacy of laxative use after major abdominal surgery. Methods: Ovid MEDLINE, Embase, Cochrane Library and PubMed databases were searched from inception to May 2019 to identify eligible RCTs focused on elective open or minimally invasive major abdominal surgery. The primary outcome was time taken to passage of stool. Secondary outcomes were time taken to tolerance of diet, time taken to flatus, length of hospital stay, postoperative complications and readmission to hospital. Results: Five RCTs with a total of 416 patients were included. Laxatives reduced the time to passage of stool (mean difference (MD) −0⋅83 (95 per cent c.i. −1⋅39 to −0⋅26) days; P = 0⋅004), but there was significant heterogeneity between studies for this outcome measure. There was no difference in time to passage of flatus (MD −0⋅17 (−0⋅59 to 0⋅25) days; P = 0⋅432), time to tolerance of diet (MD −0⋅01 (−0⋅12 to 0⋅10) days; P = 0⋅865) or length of hospital stay (MD 0⋅01(−1⋅36 to 1⋅38) days; P = 0⋅992). There were insufficient data available on postoperative complications for meta-analysis. Conclusion: Routine postoperative laxative use after major abdominal surgery may result in earlier passage of stool but does not influence other postoperative recovery parameters. Better data are required for postoperative complications and validated outcome measures.N. N. Dudi-Venkata, W. Seow, H. M. Kroon, S. Bedrikovetski, J. W. Moore, M. L. Thomas, and T. Sammou

Current practice in Australia and New Zealand for defunctioning ileostomy after rectal cancer surgery with anastomosis: Analysis of the Bi-National Colorectal Cancer Audit (BCCA)

AIM: This study aimed to investigate the use of defunctioning stomas after rectal cancer surgery in Australia and New Zealand (ANZ), as current practice is unknown. METHODS: From the Bi-National Colorectal Cancer Audit (BCCA) database, rectal cancer patients who underwent a resection between 2007 and 2019 with the formation of an anastomosis were extracted and analysed. Primary outcome was the rate of defunctioning stoma formation. Secondary outcomes were: anastomotic leakage (AL) rates and other postoperative complications, length of hospital stay (LOS), readmissions and 30-day mortality rates between stoma and no stoma groups. Propensity score-matching was performed to correct for differences in baseline characteristics between stoma and no-stoma groups. RESULTS: In total, 2,581 (89%) received a defunctioning stoma and 319 (11%) did not. There were more male patients in the stoma group (65.5 vs. 57.7% for the no-stoma group; p=0.006). The median age was 64 years in both groups. The stoma group underwent more ultra-low anterior resections (79.9 vs. 30.1%; p<0.0001), included more AJCC stage III patients (53.7 vs. 29.2%; p<0.0001) and received more neoadjuvant therapy (66.9 vs. 16.3%; p<0.0001). The AL rate was similar in both groups (5.1 vs. 6.0%; p=0.52). LOS was longer in the stoma group (8 vs. 6 days; p<0.0001) with higher 30-day readmission rates (14.9 vs. 8.3%; p=0.003). After propensity score-matching (n=208 in both groups), AL rates remained similar (2.9% for stoma vs. 5.8% for no stoma group; p=0.15), but stoma patients required less reoperations (0% vs. 8%; p=0.016). The stoma group had higher postoperative ileus rates and an increased LOS. CONCLUSION: In ANZ, most patients who underwent rectal cancer resections with the formation of an anastomosis received a defunctioning stoma. A defunctioning stoma does not prevent anastomotic leakage from occurring but is mostly associated with a lower reoperation rate. Patients with a defunctioning stoma experienced a higher postoperative ileus rate and had an increased length of hospital stay.Vera E. M. Grupa, Hidde M. Kroon, Izel Ozmen, Sergei Bedrikovetski, Nagendra N. Dudi-Venkata, Ronald A. Hunter, Tarik Sammou

Local recurrences in western low rectal cancer patients treated with or without lateral lymph node dissection after neoadjuvant (chemo) radiotherapy: An international multi-centre comparative study

Background: In the West, low rectal cancer patients with abnormal lateral lymph nodes (LLNs) are commonly treated with neoadjuvant (chemo)radiotherapy (nCRT) followed by total mesorectal excision (TME). Additionally, some perform a lateral lymph node dissection (LLND). To date, no comparative data (nCRT vs. nCRT + LLND) are available in Western patients. Methods: An international multi-centre cohort study was conducted at six centres from the Netherlands, US and Australia. Patients with low rectal cancers from the Netherlands and Australia with abnormal LLNs (≥5 mm short-axis in the obturator, internal iliac, external iliac and/or common iliac basin) who underwent nCRT and TME (LLND-group) were compared to similarly staged patients from the US who underwent a LLND in addition to nCRT and TME (LLND + group). Results: LLND + patients (n = 44) were younger with higher ASA-classifications and ypN-stages compared to LLND-patients (n = 115). LLND + patients had larger median LLNs short-axes and received more adjuvant chemotherapy (100 vs. 30%; p < 0.0001). Between groups, the local recurrence rate (LRR) was 3% for LLND + vs. 11% for LLND- (p = 0.13). Disease-free survival (DFS, p = 0.94) and overall survival (OS, p = 0.42) were similar. On multivariable analysis, LLND was an independent significant factor for local recurrences (p = 0.01). Sub-analysis of patients who underwent long-course nCRT and had adjuvant chemotherapy (LLND-n = 30, LLND + n = 44) demonstrated a lower LRR for LLND + patients (3% vs. 16% for LLND-; p = 0.04). DFS (p = 0.10) and OS (p = 0.11) were similar between groups. Conclusion: A LLND in addition to nCRT may improve loco-regional control in Western patients with low rectal cancer and abnormal LLNs. Larger studies in Western patients are required to evaluate its contribution

A prospective study of diagnostic accuracy of multidisciplinary team and radiology reporting of preoperative colorectal cancer local staging

Published on: 17 June 2022Introduction: The aim of this study was to correlate and assess diagnostic accuracy of preoperative staging at multidisciplinary team meeting (MDT) against the original radiology reports and pathological staging in colorectal cancer patients. Methods: A prospective observational study was conducted at two institutions. Patients with histologically proven colorectal cancer and available preoperative imaging were included. Preoperative tumor and nodal staging (cT and cN) as determined by the MDT and the radiology report (computed tomography [CT] and/or magnetic resonance imaging [MRI]) were recorded. Kappa statistics were used to assess agreement between MDT and the radiology report for cN staging in colon cancer, cT and cN in rectal cancer, and tumor regression grade (TRG) in patients with rectal cancer who received neoadjuvant therapy. Pathological report after surgery served as the reference standard for local staging, and AUROC curves were constructed to compare diagnostic accuracy of theMDT and radiology report. Results:Atotal of 481 patients were included. Agreement betweenMDT and radiology report for cN stage was good in colon cancer (k = .756, Confidence Interval (CI) 95% .686–.826). Agreement for cT and cN and in rectal cancer was very good (kw = .825, CI 95% .758–.892) and good (kw = .792, CI 95% .709–.875), respectively. In the rectal cancer group that received neoadjuvant therapy, agreement on TRG was very good (kw = .919, CI 95% .846–.993). AUROC curves using pathological staging indicated no difference in diagnostic accuracy betweenMDT and radiology reports for either colon or rectal cancer. Conclusion: Preoperative colorectal cancer local staging was consistent between specialist MDT review and original radiology reports, with no significant differences in diagnostic accuracy identified.Sergei Bedrikovetski, Nagendra N. Dudi-Venkata, Hidde M. Kroon, Luke H. Traeger, Warren Seow, Ryash Vather, Michael Wilks, JamesW.Moore, Tarik Sammou

Analytical micro model for size exclusion: pore blocking and permeability reduction

A pore scale model, incorporating particle and pore size distributions, and the corresponding averaged equations are discussed and applied to predict pore blocking and permeability reduction during dead-end and cross-flow microfiltration in membranes. The model assumes that size exclusion is the dominant particle retention mechanism and accounts for pore accessibility and flow reduction factors due to particle transport only via larger pores. The exact analytical solutions obtained for injection of single-sized and polydispersed particles into porous media with N different pore radii are in accordance with the experimental data on dead-end and crossflow microfiltration. Therefore, since size exclusion was the dominant particle-capture mechanism in the aforementioned experiments, good agreement between modeling and experimental data validates the proposed model for size exclusion. Furthermore, integration of the pore scale equations leads to averaged equations that significantly differ from the classical deep bed filtration model. The resulting averaged model contains constitutive relations for flux reduction and accessibility factors, which are obtained from the analytical micro scale model.A. Santos, P. Bedrikovetsky and S. Fontour

Composition changes of hydrocarbons during secondary petroleum migration (case study in Cooper Basin, Australia)

The reliable mathematical modelling of secondary petroleum migration that incorporates structural geology and mature source rocks in the basin model, allows for prediction of the reservoir location, yielding the significant enhancement of the probability of exploration success. We investigate secondary petroleum migration with a significant composition difference between the source and oil pools. In our case study, the secondary migration period is significantly shorter than the time of the hydrocarbon pulse generation. Therefore, neither adsorption nor dispersion of components can explain the concentration difference between the source rock and the reservoir. For the first time, the present paper proposes deep bed filtration of hydrocarbons with component kinetics retention by the rock as a physics mechanism explaining compositional grading. Introduction of the component capture rate into mass balance transport equation facilitates matching the concentration difference for heavy hydrocarbons, and the tuned filtration coefficients vary in their common range. The obtained values of filtration coefficients monotonically increase with molecular weight and consequently affects the size of the oleic component, as predicted by the analytical model of deep bed filtration. The modelling shows a negligible effect of component dispersion on the compositional grading.Sara Borazjani, David Kulikowski, Khalid Amrouch and Pavel Bedrikovetsk

Effects of fines migration on well productivity during steady state production

Well clogging and productivity decline have been widely observed in oil, gas, and artesian wells producing reservoir fines. The phenomenon has been explained by the lifting, migration, and subsequent plugging of the pores by the fine particles, finally resulting in permeability decrease. This has been observed in numerous core flood tests and field cases. In this work, the new basic equations for the detachment of fine particles, their migration, and size exclusion, causing the rock permeability decline, have been derived. The analytical model, developed for the regime of steady-state production with the gradual accumulation of strained particles, exhibits the linear skin factor growth versus the amount of produced reservoir fines. The modeling data are in good agreement with the well production history. The model allows predicting well productivity decline due to fines production based on short-term production data.Abbas Zeinijahromi, Alexandre Vaz, Pavel Bedrikovetsky and Sara Borazjan