The number of comorbidities as an important cofactor to ASA class in predicting postoperative outcome: An international multicentre cohort study.

BACKGROUND: Multimorbidity is a growing burden in our ageing society and is associated with perioperative morbidity and mortality. Despite several modifications to the ASA physical status classification, multimorbidity as such is still not considered. Thus, the aim of this study was to quantify the burden of comorbidities in perioperative patients and to assess, independent of ASA class, its potential influence on perioperative outcome. METHODS: In a subpopulation of the prospective ClassIntra® validation study from eight international centres, type and severity of anaesthesia-relevant comorbidities were additionally extracted from electronic medical records for the current study. Patients from the validation study were of all ages, undergoing any type of in-hospital surgery and were followed up until 30 days postoperatively to assess perioperative outcomes. Primary endpoint was the number of comorbidities across ASA classes. The associated postoperative length of hospital stay (pLOS) and Comprehensive Complication Index (CCI®) were secondary endpoints. On a scale from 0 (no complication) to 100 (death) the CCI® measures the severity of postoperative morbidity as a weighted sum of all postoperative complications. RESULTS: Of 1421 enrolled patients, the mean number of comorbidities significantly increased from 1.5 in ASA I (95% CI, 1.1-1.9) to 10.5 in ASA IV (95% CI, 8.3-12.7) patients. Furthermore, independent of ASA class, postoperative complications measured by the CCI® increased per each comorbidity by 0.81 (95% CI, 0.40-1.23) and so did pLOS (geometric mean ratio, 1.03; 95% CI, 1.01-1.06). CONCLUSIONS: These data quantify the high prevalence of multimorbidity in the surgical population and show that the number of comorbidities is predictive of negative postoperative outcomes, independent of ASA class.

Feasibility and Accuracy of Wrist-Worn Sensors for Perioperative Monitoring During and After Major Abdominal Surgery: An Observational Study.

INTRODUCTION: Continuous, ambulatory perioperative monitoring using wearable devices has shown promise for earlier detection of physiological deterioration and postoperative complications, preventing 'failure-to-rescue'. This study aimed to compare the accuracy of vital signs measured by wrist-based wearables with gold standard measurements from vital signs monitors or nurse assessments in major abdominal surgery. METHODS: Adult patients were eligible for inclusion in this prospective observational study validating the Empatica E4 wrist sensor intraoperatively and postoperatively. The primary outcomes were the 95% limits of agreement (LoA) between manual and device recordings of heart rate (HR) and temperature evaluated via Bland-Altman analysis. Secondary analysis was conducted using Clarke-Error grid analysis. RESULTS: Overall, 31 patients were recruited, and 27 patients completed the study. The median duration of recording per patient was 70.3 h, and a total of 2112 h of data recording were completed. Wrist-based HR measurement was accurate and moderately precise (bias: 0.3 bpm; 95% LoA -15.5 to 17.1), but temperature measurement was neither accurate nor precise (bias -2.2°C; 95% LoA -6.0 to 1.6). On Clarke-Error grid analysis, 74.5% and 29.6% of HR and temperature measurements, respectively, fell within the acceptable range of reference standards. CONCLUSIONS: Continuous perioperative monitoring of HR and temperature after major abdominal surgery using wrist-based sensors is feasible but was limited in this study by low precision. While wrist-based devices offer promise for the continuous monitoring of high-risk surgical patients, current technology is inadequate. Ongoing device hardware and software innovation with robust validation is required before such technologies can be routinely adopted in clinical practice.

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.

Delayed Gastric Emptying and Gastric Remnant Function After Pancreaticoduodenectomy: A Systematic Review of Objective Assessment Modalities.

BACKGROUND: Delayed gastric emptying (DGE) is a frequent complication after pancreaticoduodenectomy (PD). The diagnosis of DGE is based on International Study Group for Pancreatic Surgery (ISGPS) clinical criteria and objective assessments of DGE are infrequently used. The present literature review aimed to identify objective measures of DGE following PD and determine whether these measures correlate with the clinical definition of DGE. METHODS: A systematic search was performed using the MEDLINE Ovid, EMBASE, Google Scholar and CINAHL databases for studies including pancreatic surgery, delayed gastric emptying and gastric motility until June 2022. The primary outcome was modalities undertaken for the objective measurement of DGE following PD and correlation between objective measurements and clinical diagnosis of DGE. Relevant risk of bias analysis was performed. RESULTS: The search revealed 4881 records, of which 46 studies were included in the final analysis. There were four objective modalities of DGE assessment including gastric scintigraphy (n = 28), acetaminophen/paracetamol absorption test (n = 10), fluoroscopy (n = 6) and the 13C-acetate breath test (n = 3). Protocols were inconsistent, and reported correlations between clinical and objective measures of DGE were variable; however, amongst these measures, at least one study directly or indirectly inferred a correlation, with the greatest evidence accumulated for gastric scintigraphy. CONCLUSION: Several objective modalities to assess DGE following PD have been identified and evaluated, however are infrequently used. Substantial variability exists in the literature regarding indications and interpretation of these tests, and there is a need for a real-time objective modality which correlates with ISGPS DGE definition after PD.

Localized bioelectrical conduction block from radiofrequency gastric ablation persists after healing: safety and feasibility in a recovery model.

Gastric ablation has demonstrated potential to induce conduction blocks and correct abnormal electrical activity (i.e., ectopic slow-wave propagation) in acute, intraoperative in vivo studies. This study aimed to evaluate the safety and feasibility of gastric ablation to modulate slow-wave conduction after 2 wk of healing. Chronic in vivo experiments were performed in weaner pigs (n = 6). Animals were randomly divided into two groups: sham-ablation (n = 3, control group; no power delivery, room temperature, 5 s/point) and radiofrequency (RF) ablation (n = 3; temperature-control mode, 65°C, 5 s/point). In the initial surgery, high-resolution serosal electrical mapping (16 × 16 electrodes; 6 × 6 cm) was performed to define the baseline slow-wave activation profile. Ablation (sham/RF) was then performed in the mid-corpus, in a line around the circumferential axis of the stomach, followed by acute postablation mapping. All animals recovered from the procedure, with no sign of perforation or other complications. Two weeks later, intraoperative high-resolution mapping was repeated. High-resolution mapping showed that ablation successfully induced sustained conduction blocks in all cases in the RF-ablation group at both the acute and 2 wk time points, whereas all sham-controls had no conduction block. Histological and immunohistochemical evaluation showed that after 2 wk of healing, the lesions were in the inflammation and early proliferation phase, and interstitial cells of Cajal (ICC) were depleted and/or deformed within the ablation lesions. This safety and feasibility study demonstrates that gastric ablation can safely and effectively induce a sustained localized conduction block in the stomach without disrupting the surrounding slow-wave conduction capability.NEW & NOTEWORTHY Ablation has recently emerged as a tool for modulating gastric electrical activation and may hold interventional potential for disorders of gastric function. However, previous studies have been limited to the acute intraoperative setting. This study now presents the safety of gastric ablation after postsurgical recovery and healing. Localized electrical conduction blocks created by ablation remained after 2 wk of healing, and no perforation or other complications were observed over the postsurgical period.

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.

Outcomes following out-of-hours acute cholecystectomy: A systematic review and meta-analysis.

BACKGROUND: Cholecystectomy is one of the most commonly performed abdominal operations. Rising demands on acute operating theater availability and resource utilization in the daytime have led to acute cholecystectomy being performed out-of-hours (in the evenings, at night, or on weekends), although it remains unknown whether outcomes differ between out-of-hours and in-hours (during the daytime on weekdays) acute cholecystectomy. This systematic review and meta-analysis aimed to compare outcomes following out-of-hours versus in-hours acute cholecystectomy. METHODS: The study protocol was prospectively registered on PROSPERO (ID: CRD42021226127). MEDLINE, EMBASE, and Scopus databases were systematically searched for studies comparing outcomes following out-of-hours and in-hours acute cholecystectomy in adults with any acute benign gallbladder disease. The outcomes of interest were rates of bile leakage, bile duct injury, overall postoperative complications, conversion to open cholecystectomy, specific intraoperative and postoperative complications, length of stay, readmission, and mortality. Subgroup (evening/night-time vs. daytime, weekend vs. weekday, acute surgical unit [ASU]-only, non-ASU, and laparoscopic-only) and sensitivity analyses of adjusted multivariate regression analysis results was also performed. RESULTS: Eleven studies were included. There were no differences between out-of-hours and in-hours acute cholecystectomy for rates of bile leakage, bile duct injury, overall postoperative complications, conversion to open cholecystectomy, operative duration, readmission, mortality, and postoperative length of stay. Higher rates of postoperative sepsis (odds ratio, 1.58; 95% confidence interval, 1.04-2.41; p = 0.03) and pneumonia (odds ratio, 1.55; 95% confidence interval, 1.06-2.26; p = 0.02) were observed following out-of-hours acute cholecystectomy on univariate meta-analysis, but not after the adjusted multivariate meta-analysis. Higher conversion rates were observed when out-of-hours cholecystectomy was performed in centers without an ASU. CONCLUSION: This systematic review and meta-analysis has not shown an increased risk in overall or specific complications associated with out-of-hours compared with in-hours acute cholecystectomy. However, future studies should assess the potential impact of structural hospital factors, such as an ASU, on outcomes following out-of-hours acute cholecystectomy. LEVEL OF EVIDENCE: Systematic Review and Meta-Analysis Study, Level IV.

Transcutaneous Electrical Stimulation for Neurogenic Bladder Dysfunction Following Spinal Cord Injury: Meta-Analysis of Randomized Controlled Trials.

OBJECTIVES: To assess the efficacy of transcutaneous electrical nerve stimulation (TENS) for neurogenic bladder dysfunction secondary to spinal cord injury (SCI). MATERIALS AND METHODS: A systematic search of MEDLINE, EMBASE, Web of Science, Scopus, and Cochrane libraries up to February 2021 was performed using PRISMA methodology. All randomized controlled trials (RCTs) that studied TENS for neurogenic bladder in a SCI population were included. The primary outcomes of interest were maximum cystometric capacity (MCC) and maximum detrusor pressure (Pdet). Meta-analysis was conducted with RevMan v5.3. RESULTS: Six RCTs involving 353 participants were included. Meta-analysis showed that TENS significantly increased MCC (standardized mean difference 1.11, 95% confidence interval [CI] 0.08-2.14, p = 0.03, I2  = 54%) in acute SCI. No benefits were seen for maximum Pdet. TENS was associated with no major adverse events. CONCLUSIONS: TENS may be an effective, safe intervention for neurogenic bladder dysfunction following SCI. Further studies are essential to confirm these results and more work is required to determine optimal stimulation parameters and duration of the treatment.

Variable Gut Function Recovery After Right vs. Left Colectomy May Be Due to Rectosigmoid Hyperactivity.

It is established that gut function recovers slower after right vs. left colectomies with higher rates of prolonged post-operative ileus (PPOI), but the reason is unclear. Development of PPOI is multifactorial. A recent manometry study in right colectomy patients showed that the distal colon becomes hyperactive after surgery with predominantly cyclic motor patterns (CMPs). In this perspective, we evaluate the hypothesis that the slower gut recovery after right hemicolectomy could be induced by a functional obstruction due to hyperactive CMPs.

Risk factors for readmission with dehydration after ileostomy formation: A systematic review and meta-analysis.

AIM: Ileostomy formation is a commonly performed procedure with substantial associated morbidity. Patients with an ileostomy experience high rates of unplanned hospital readmission with dehydration, and such events have a long-term health and economic impact. Reports of the significant risk factors associated with these readmissions have been inconsistent. This study aimed to identify the significant risk factors for readmission with dehydration following ileostomy formation. METHOD: A systematic search was conducted using the Medline, Embase, Cochrane and CINAHL databases. All original research articles reporting risk factors for readmission with dehydration following ileostomy formation in adults were included. The primary outcome was the pooled risk ratio of clinically relevant variables potentially associated with dehydration-related readmission following ileostomy formation. The secondary outcome was the incidence of dehydration-related readmission. RESULTS: Ten studies (27 089 patients) were included. The incidences of 30- and 60-day readmission with dehydration were 5.0% (range 2.1%-13.2%) and 10.3% (range 7.3%-14.1%), respectively. Eight variables were found to be significantly associated with dehydration-related readmission: age ≥65 years, body mass index ≥30 kg/m2 , diabetes mellitus, hypertension, renal comorbidity, regular diuretic use, ileal pouch-anal anastomosis procedure and length of stay after index admission. A preoperative diagnosis of colorectal cancer was less likely to result in readmission with dehydration. CONCLUSION: Readmission with dehydration following ileostomy formation is a significant issue with several risk factors. Awareness of these risk factors will help inform the design of future studies addressing risk prediction, allow risk stratification of ileostomates and aid in the development of personalized prevention strategies.

Relationships between serum electrolyte concentrations and ileus: A joint clinical and mathematical modeling study.

AIM: Prolonged postoperative ileus (PPOI) occurs in around 15% of patients after major abdominal surgery, posing a significant clinical and economic burden. Significant fluid and electrolyte changes may occur peri-operatively, potentially contributing to PPOI; however, this association has not been clearly elucidated. A joint clinical-theoretical study was undertaken to evaluate peri-operative electrolyte concentration trends, their association with ileus, and predicted impact on bioelectrical slow waves in interstitial cells of Cajal (ICC) and smooth muscle cells (SMC). METHODS: Data were prospectively collected from 327 patients undergoing elective colorectal surgery. Analyses were performed to determine associations between peri-operative electrolyte concentrations and prolonged ileus. Biophysically based ICC and SMC mathematical models were adapted to evaluate the theoretical impacts of extracellular electrolyte concentrations on cellular function. RESULTS: Postoperative day (POD) 1 calcium and POD 3 chloride, sodium were lower in the PPOI group (p < 0.05), and POD3 potassium was higher in the PPOI group (p < 0.05). Deficits beyond the reference range in PPOI patients were most notable for sodium (Day 3: 29.5% ileus vs. 18.5% no ileus, p = 0.04). Models demonstrated an 8.6% reduction in slow-wave frequency following the measured reduction in extracellular NaCl on POD5, with associated changes in cellular slow-wave morphology and amplitude. CONCLUSION: Low serum sodium and chloride concentrations are associated with PPOI. Electrolyte abnormalities are unlikely to be a primary mechanism of ileus, but their pronounced effects on cellular electrophysiology predicted by modeling suggest these abnormalities may adversely impact motility recovery. Resolution and correction of electrolyte abnormalities in ileus may be clinically relevant.

Gastric ablation as a novel technique for modulating electrical conduction in the in vivo stomach.

Gastric motility is coordinated by underlying bioelectrical "slow wave" activity. Slow wave dysrhythmias are associated with motility disorders, including gastroparesis, offering an underexplored potential therapeutic target. Although ablation is widely used to treat cardiac arrhythmias, this approach has not yet been trialed for gastric electrical abnormalities. We hypothesized that ablation can create localized conduction blocks and modulate slow wave activation. Radiofrequency ablation was performed on the porcine serosa in vivo, encompassing a range of parameters (55-85°C, adjacent points forming a line, 5-10 s/point). High-resolution electrical mapping (16 × 16 electrodes; 6 × 6 cm) was applied to define baseline and acute postablation activation patterns. Tissue damage was evaluated by hematoxylin and eosin and c-Kit stains. Results demonstrated that RF ablation successfully induced complete conduction block and a full thickness lesion in the muscle layer at energy doses of 65-75°C for 5-10 s/point. Gastric ablation may hold therapeutic potential for gastric electrical abnormalities in the future.NEW & NOTEWORTHY This study presents gastric ablation as a new method for modulating slow wave activation and propagation in vivo, by creating localized electrical conduction blocks in the stomach, validated by high-resolution electrical mapping and histological tissue analysis. The results define the effective energy dose range for creating conduction blocks, while maintaining the mucosal and submucosal integrity, and demonstrate the electrophysiological effects of ablation. In future, gastric ablation can now be translated toward disrupting dysrhythmic slow wave activation.

Patient-Administered Transcutaneous Electrical Nerve Stimulation for Postoperative Pain Control After Laparoscopic Cholecystectomy: A Randomized, Sham-Controlled Feasibility Trial.

OBJECTIVES: Transcutaneous electrical nerve stimulation (TENS) is a noninvasive analgesic neurostimulation modality. Difficulties in clinical trial blinding and therapy administration have limited conclusions of previous trials. The aims of this study were to first investigate the feasibility and acceptability of patient-administered TENS after surgery, and second, the feasibility of using sub-sensory TENS as a proxy sham group for patient-blinding. MATERIALS AND METHODS: Over a four-month period, patients undergoing laparoscopic cholecystectomy at a single center were randomized to receive maximally tolerable high-intensity (HI) TENS or sub-sensory low-intensity (LI) TENS. Patients and outcome assessors were blinded. Primary outcomes were the feasibility, tolerability, and acceptability of patient self-administered TENS, measured by patient-reported outcomes, and the strength of patient-blinding, measured using the James Blinding Index (JBI). Secondary outcomes explored clinical recovery and analgesic efficacy. RESULTS: Nineteen patients were screened for inclusion; ten patients were randomized and completed the feasibility study. TENS therapy was variably utilized (median duration of TENS 5.3 hours/day [IQR: 4.1-6.9]). The JBI was 0.7, indicating a strong strength of blinding. Majority of patients found the TENS unit easy to use (90%) and were confident with self-administration (100%). No patients experienced adverse effects of TENS use. CONCLUSIONS: Patient-administered TENS is safe and acceptable. Future studies may use sub-sensory TENS as a proxy sham control to more reliably blind patients. A larger, double-blinded RCT employing these techniques is now needed to determine the analgesic efficacy of TENS in an enhanced recovery setting, and its potential to reduce opiate usage.

Re-admissions after ileostomy formation: a retrospective analysis from a New Zealand tertiary centre.

BACKGROUND: Ileostomy formation is a commonly performed procedure in colorectal surgery. The morbidity associated with ileostomies is substantial, particularly for unplanned hospital re-admissions and re-admissions with dehydration. Studies of post-ileostomy re-admissions from an Australasian institution are currently lacking. This retrospective study aimed to quantify the 60-day re-admission rate after ileostomy formation in a New Zealand tertiary centre and to determine the predictive factors. METHODS: The surgical database of Auckland City Hospital was searched for all patients aged ≥18 years with a new ileostomy formed between first January 2015 and first January 2019. Patient electronic medical records were reviewed to obtain data regarding the primary outcome of re-admissions within 60 days of discharge, as well as patient and operative variables. Multivariate regression analysis was performed to identify independent predictors of all-cause re-admissions and re-admissions with dehydration. RESULTS: A total of 246 patients with 266 ileostomy formations were included. The 60-day re-admission rate was 29.3%, with dehydration present in 27.0% of these re-admissions. Renal impairment at discharge (odds ratio 2.819, 95% confidence interval 1.087-7.310) and the presence of at least one Clavien-Dindo 1 complication (odds ratio 2.268, 95% confidence interval 1.301-3.954) were independently associated with all-cause re-admission. The independent predictors of re-admission with dehydration were renal impairment at discharge, codeine prescribed on discharge, Charlson Comorbidity Index and body mass index. CONCLUSION: Unplanned hospital re-admission following ileostomy formation is a significant issue in the New Zealand patient population. Some patient groups are at particularly high risk, such as those with renal impairment at discharge.

Manometry of the Human Ileum and Ileocaecal Junction in Health, Disease and Surgery: A Systematic Review.

Background: The terminal ileum and ileocaecal junction form a transition zone in a relatively inaccessible portion of the gastrointestinal tract. Little is known about the motility of this region with few detailed studies, indicating the need for a robust synthesis of current knowledge. This review aimed to evaluate the quantitative and qualitative data on the manometry findings of the terminal ileum and ileocaecal junction during the fasting and post-prandial periods in healthy individuals and patients with motility disorders or patients after bowel surgery. Methods: A systematic search of five databases (Medline, Pubmed, Embase, Scopus, and Cochrane Library) was performed. Studies that presented manometry data from the human ileum or ileocaecal junction were included. Results: Forty-two studies met the inclusion criteria. The main motility patterns reported in the terminal ileum during fasting were the migrating motor complex, discrete clustered contractions, prolonged propagated contractions and phasic contractions. Post-prandial motility featured irregular, intense contractions. Some studies found a region of sustained increased pressure at the ileocaecal junction while others did not. Patients with motility disorders showed differences in manometry including retrograde propagation of phase III. Patients post-bowel surgery showed differences including higher incidence of phase III. Conclusion: Motility patterns of the terminal ileum differ between fasting and fed states. Large variability existed in manometry recordings of the terminal ileum. Technical challenges and lack of standardized definitions may reduce accuracy of manometry assessment. Further research is needed to understand how this key portion of the gut physiologically functions.

Costs and outcomes of sacral nerve stimulation for faecal incontinence in New Zealand: a 10-year observational study.

BACKGROUND: Faecal incontinence is a debilitating condition that affects more than 10% of New Zealanders. In well-selected cohorts, sacral nerve stimulation (SNS) offers a therapeutic option for patients refractory to conservative and other surgical treatments. The aim of this study was to define the clinical efficacy, rate of reinterventions and explants and healthcare costs associated with SNS in the New Zealand setting. METHODS: Clinical records of all consecutive patients undergoing SNS at Auckland District Health Board between 2008 and 2019 were retrospectively reviewed and paired with the results of a postal survey to 100 patients who had retained the implant at August 2019. RESULTS: Over the 10-year period, 142 patients underwent stage 1 SNS, of which 126 (88.7%) progressed to a permanent implant and 108 (76.1%) had retained the implant at a median follow-up of 41.2 months. SNS therapy significantly reduced weekly faecal incontinence episodes (P < 0.001), medication use (P < 0.001) and pad use (P = 0.01) at median 41.2 months. Complications were common, with infections in 9.2%, lead fractures in 4.9% and component migrations in 12.7%. The probability of retaining the same battery at 6.3 years was >90%. In total, reintervetion was necessary in 41.5% of the cohort. SNS therapy was expensive, costing >NZ$30 000 for implantation, increasing to >NZ$46 000 if a further reintervention was required. CONCLUSIONS: SNS is an effective long-term therapy for faecal incontinence. However, it is expensive and associated with a high rate of reinterventions and explants.

Slow-wave coupling across a gastroduodenal anastomosis as a mechanism for postsurgical gastric dysfunction: evidence for a "gastrointestinal aberrant pathway".

Postsurgical gastric dysfunction is common, but the mechanisms are varied and poorly understood. The pylorus normally acts as an electrical barrier isolating gastric and intestinal slow waves. In this report, we present an aberrant electrical conduction pathway arising between the stomach and small intestine, following pyloric excision and surgical anastomosis, as a novel disease mechanism. A patient was referred with postsurgical gastroparesis following antrectomy, gastroduodenostomy, and vagotomy for peptic ulceration. Scintigraphy confirmed markedly abnormal 4-h gastric retention. Symptoms included nausea, vomiting, postprandial distress, and reflux. Intraoperative, high-resolution electrical mapping was performed across the anastomosis immediately before revision gastrectomy, and the resected anastomosis underwent immunohistochemistry for interstitial cells of Cajal. Mapping revealed continuous, stable abnormal retrograde slow-wave propagation through the anastomosis, with slow conduction occurring at the scar (4.0 ± 0.1 cycles/min; 2.5 ± 0.6 mm/s; 0.26 ± 0.15 mV). Stable abnormal retrograde propagation continued into the gastric corpus with tachygastria (3.9 ± 0.2 cycles/min; 1.6 ± 0.5 mm/s; 0.19 ± 0.12 mV). Histology confirmed ingrowth of atypical ICC through the scar, defining an aberrant pathway enabling transanastomotic electrical conduction. In conclusion, a "gastrointestinal aberrant pathway" is presented as a novel proposed cause of postsurgical gastric dysfunction. The importance of aberrant anastomotic conduction in acute and long-term surgical recovery warrants further investigation.NEW & NOTEWORTHY High-resolution gastric electrical mapping was performed during revisional surgery in a patient with severe gastric dysfunction following antrectomy and gastroduodenostomy. The results revealed continuous propagation of slow waves from the duodenum to the stomach, through the old anastomotic scar, and resulting in retrograde-propagating tachygastria. Histology showed atypical interstitial cells of Cajal growth through the anastomotic scar. Based on these results, we propose a "gastrointestinal aberrant pathway" as a mechanism for postsurgical gastric dysfunction.

Colonic Electromechanical Abnormalities Underlying Post-operative Ileus: A Systematic and Critical Review.

Post-operative ileus (POI) is an inevitable consequence of major abdominal surgery, and may be prolonged in up to 30% of patients. Ileus is commonly presumed to result from paralysis of the GI tract, though there is little direct evidence to support this view. The aim of this review is to systematically search and critically review the literature investigating post-operative colonic electrical and mechanical activity. MEDLINE and Embase databases were systematically searched for articles investigating post-operative colonic motor or electrical activity in human patients. Nineteen original articles investigating post-operative colonic motor or electrical activity were identified. Most studies have used low-resolution techniques, with intermittent recordings of colonic motility. Numerous studies have shown that colonic electrical and motor activity does not cease routinely following surgery, but is of abnormal character for 3-6 days following laparotomy. One recent high-resolution manometry study identified hyperactive cyclic motor patterns occurring in the distal colon on the first post-operative day. Low-resolution studies have shown colonic slow waves are not inhibited by surgery, and are present even in the immediate post-operative period. Recovery of normal motility appears to occur in a proximal to distal direction and is temporally correlated with the clinical return of bowel function. No studies have investigated motility specifically in prolonged POI. Future studies should use high-resolution techniques to accurately characterise abnormalities in electrical and mechanical function underlying POI, and correlate these changes with clinical recovery of bowel function.

Electrical Stimulation and Recovery of Gastrointestinal Function Following Surgery: A Systematic Review.

OBJECTIVES: Postoperative ileus occurs in approximately 5-15% of patients following major abdominal surgery, and poses a substantial clinical and economic burden. Electrical stimulation has been proposed as a means to aid postoperative gastrointestinal (GI) recovery, but no methods have entered routine clinical practice. A systematic review was undertaken to assess electrical stimulation techniques and to evaluate their clinical efficacy in order to identify promising areas for future research. MATERIALS AND METHODS: Literature was searched using MEDLINE, EMBASE, Google Scholar and by assessing relevant clinical trial databases. Studies investigating the use of electrical stimulation for postoperative GI recovery were included, regardless of methods used or outcomes measured. A critical review was constructed encompassing all included studies and evaluating and synthesizing stimulation techniques, protocols, and clinical outcomes. RESULTS: A broad range of neuromodulation strategies and protocols were identified and assessed. Improved postoperative GI recovery following electrical stimulation was reported by 55% of studies (10/18), most commonly those assessing transcutaneous electrical nerve stimulation and electroacupuncture therapy (7/10). Several studies reported shorter time to first flatus and stool, shorter duration of hospital stay, and reduced postoperative pain. However, inconsistent reporting and limitations in trial design were common, compromising a definitive determination of electrical stimulation efficacy. CONCLUSIONS: Electrical stimulation appears to be a promising methodology to aid postoperative GI recovery, but greater attention to mechanisms of action and clinical trial quality is necessary for progress. Future research should also aim to apply validated and standardized gut recovery outcomes and consistent neuromodulation methodologies.

Prolonged Postoperative Ileus Significantly Increases the Cost of Inpatient Stay for Patients Undergoing Elective Colorectal Surgery: Results of a Multivariate Analysis of Prospective Data at a Single Institution.

BACKGROUND: Prolonged postoperative ileus is a common major complication after abdominal surgery. Retrospective data suggest that ileus doubles the cost of inpatient stay. However, current economic impact data are based on retrospective studies that rely on clinical coding to diagnose ileus. OBJECTIVE: The aim of this study was to determine the economic burden of ileus for patients undergoing elective colorectal surgery. DESIGN: Economic data were audited from a prospective database of patients who underwent surgery at Auckland City Hospital between September 2012 and June 2014. SETTINGS: Auckland City Hospital is a large tertiary referral center, using an enhanced recovery after surgery protocol. PATIENTS: Patients were prospectively diagnosed with prolonged postoperative ileus using a standardized definition. MAIN OUTCOME MEASURES: The cost of inpatient stay was analyzed with regard to patient demographics and operative and postoperative factors. A multivariate analysis was performed to determine the cost of ileus when accounting for other significant covariates. RESULTS: Economic data were attained from 325 patients, and 88 patients (27%) developed ileus. The median inpatient cost (New Zealand dollars) for patients with prolonged ileus, including complication rates and length of stay, was $27,981 (interquartile range= $20,198 to $42,174) compared with $16,317 (interquartile range = $10,620 to $23,722) for other patients, a 71% increase in cost (p < 0.005). Ileus increased all associated healthcare costs, including medical/nursing care, radiology, medication, laboratory costs, and allied health (p < 0.05). Multivariate analysis showed that ileus remained a significant financial burden (p < 0.005) when considering rates of major complications and length of stay. LIMITATIONS: This is a single-institution study, which may impact the generalizability of our results. CONCLUSIONS: Prolonged ileus causes a substantial financial burden on the healthcare system, in addition to greater complication rates and length of stay in these patients. This is the first study to assess the financial impact of prolonged ileus, diagnosed prospectively using a standardized definition. See Video Abstract at http://links.lww.com/DCR/A825.