Hugh Mackenzie

Mass Spectrometric Analysis of Exhaled Breath for the Identification of Volatile Organic Compound Biomarkers in Esophageal and Gastric Adenocarcinoma

Objective: The present study assessed whether exhaled breath analysis using Selected Ion Flow Tube Mass Spectrometry could distinguish esophageal and gastric adenocarcinoma from noncancer controls. Background: The majority of patients with upper gastrointestinal cancer present with advanced disease, resulting in poor long-term survival rates. Novel methods are needed to diagnose potentially curable upper gastrointestinal malignancies. Methods: A Profile-3 Selected Ion Flow Tube Mass Spectrometry instrument was used for analysis of volatile organic compounds (VOCs) within exhaled breath samples. All study participants had undergone upper gastrointestinal endoscopy on the day of breath sampling. Receiver operating characteristic analysis and a diagnostic risk prediction model were used to assess the discriminatory accuracy of the identified VOCs. Results: Exhaled breath samples were analyzed from 81 patients with esophageal (N = 48) or gastric adenocarcinoma (N = 33) and 129 controls including Barretts metaplasia (N = 16), benign upper gastrointestinal diseases (N = 62), or a normal upper gastrointestinal tract (N = 51). Twelve VOCs—pentanoic acid, hexanoic acid, phenol, methyl phenol, ethyl phenol, butanal, pentanal, hexanal, heptanal, octanal, nonanal, and decanal—were present at significantly higher concentrations (P < 0.05) in the cancer groups than in the noncancer controls. The area under the ROC curve using these significant VOCs to discriminate esophageal and gastric adenocarcinoma from those with normal upper gastrointestinal tracts was 0.97 and 0.98, respectively. The area under the ROC curve for the model and validation subsets of the diagnostic prediction model was 0.92 ± 0.01 and 0.87 ± 0.03, respectively. Conclusions: Distinct exhaled breath VOC profiles can distinguish patients with esophageal and gastric adenocarcinoma from noncancer controls.

Randomized controlled trial on the effect of coaching in simulated laparoscopic training.

BackgroundThe effect of coaching on surgical quality and understanding in simulated training remains unknown. The aim of this study was compare the effects of structured coaching and autodidactic training in simulated laparoscopic surgery.MethodsSeventeen surgically naive medical students were randomized into two groups: eight were placed into an intervention group and received structured coaching, and nine were placed into a control group and received no training. They each performed 10 laparoscopic cholecystectomies on a virtual reality simulator. The surgical quality of the first, fifth, and 10th operations was evaluated by 2 independent blinded assessors using the Competency Assessment Tool (CAT) for cholecystectomy. Understanding of operative strategy was tested before the first, fifth, and 10th operation. Performance metrics, path length, total number of movements, operating time, and error frequency were evaluated. The groups were compared by the Mann–Whitney U test. Proficiency gain curves were plotted using curve fit and CUSUM models; change point analysis was performed by multiple Wilcoxon signed rank analyses.ResultsThe intervention group scored significantly higher on the CAT assessment of procedures 1, 5, and 10, with increasing disparity. They also performed better in the knowledge test at procedures 5 and 10, again with an increasing difference. The learning curve for error frequency of the intervention group reached competency after operation 7, whereas the control group did not plateau by procedure 10. The learning curves of both groups for path length and number movements were almost identical; the mean operation time was shorter for the control group.ConclusionsClinically relevant markers of proficiency including error reduction, understanding of surgical strategy, and surgical quality are significantly improved with structured coaching. Path length and number of movements representing merely manual skills are developed with task repetition rather than influenced by coaching. Structured coaching may represent a key component in the acquisition of procedural skills.

Proficiency gain curve and predictors of outcome for laparoscopic ventral mesh rectopexy

BACKGROUND Laparoscopic ventral mesh rectopexy (LVMR) is a well-recognized treatment for rectal prolapse and high-grade rectal intussusception. However, it is technically complex with the possibility of clinically relevant morbidity. The objectives were to define (i) the efficacy and safety of LVMR, (ii) risk factors for poor clinical outcome, and (iii) the autodidactic proficiency gain curve. METHODS All primary LVMR cases performed by the senior author between January 1997 and February 2013 were included in the study. In addition to the clinical outcomes, quality-of-life outcomes, including the Cleveland Clinic Incontinence Score and obstructive defecation syndrome score, were evaluated. Risk factors for operative complications, recurrence, and mesh-related complications were identified by the use of logistic regression models. Proficiency gain curves for functional and clinical outcomes were assessed using cumulative sum curves. RESULTS A total of 636 LVMRs were performed during the study period. The mean percentage improvement in the Cleveland Clinic Incontinence Score and obstructive defecation syndrome score were 89.7% (SD 21.8%) and 56.7% (SD 20.6%). The operative complication, recurrent symptoms, and mesh-related complication rates were 9.9%, 9.4%, and 3.1%, respectively. Predictors of operative complication were male sex and previous abdominal operation; the only predictor of mesh-related complications and recurrence was the use of polyester mesh. The learning curve for operative time was 54 cases, but for other clinical and quality-of-life outcomes was between 82 and 105 cases. CONCLUSION LVMR treats rectal prolapse effectively, providing good symptomatic relief with minimal morbidity. However, the self-taught learning curve for this complex laparoscopic procedure is protracted.

First international training and assessment consensus workshop on transanal total mesorectal excision (taTME)

The interest and adoption of transanal total mesorectal excision (taTME) is growing rapidly worldwide. This new technique has arisen thanks to advances in minimally invasive surgery and transanal approaches. The ultimate goal of the procedure is to improve clinical, oncological and functional outcomes of rectal excision by obtaining a meticulous TME resection in cancer cases, whilst avoiding injury to surrounding pelvic structures. Transanal TME is a complex procedure and demands excellent, prerequisite surgical skills in order to complete the operation in a safe and efficient manner. The ‘‘bottom-up’’ approach also reveals a completely new viewpoint of the pelvic anatomy for most surgeons. The combination of complexity and unfamiliarity has triggered the occurrence of adverse events, such as urethral injuries [1, 2], which were rarely encountered previously in conventional laparoscopic or open resections. Uptake of a new operation is also associated with a proficiency-gain curve during which there is increased morbidity and mortality [3]. These adverse outcomes during the introduction and dissemination of taTME must be honestly reported, properly analysed and addressed accordingly. Only then can we avoid a ‘‘dip’’ in the adoption curve we saw early on in the laparoscopic experience due to port site metastasis.

Management and Outcomes of Esophageal Perforation: A National Study of 2,564 Patients in England.

OBJECTIVES:Traditionally esophageal perforation is a rare clinical emergency that confers a high rate of mortality and major morbidity. The objective of this study was to establish the annual rate and mortality from esophageal perforation and determine the effect of hospital volume on clinical outcomes.METHODS:Hospital Episode Statistics database was used for the identification of patients admitted to hospitals within England with esophageal perforation between 2001 and 2012. The influence of hospital volume and treatment approach upon clinical outcomes was analyzed using multivariable analysis to control for patient age and medical comorbidities that may influence outcome.RESULTS:Over the 12-year study period 2,564 patients with esophageal perforation were treated at 158 hospitals. The 30- and 90-day mortality rates were 30.0 and 38.8%, respectively. Esophageal perforation etiology was spontaneous in 81.9% and iatrogenic in 5.9% of cases. There was a significant increase in the percentage of patients managed supportively and a reduction in surgical management over time. Furthermore there were significant reductions in 30-day (36.6% to 24.9%; P<0.001) and 90-day mortality (44.1% to 35.4%; P=0.006) over the 12-year study period. Important patient demographics associated with 30- and 90-day mortality included age ≥70 years, preoperative congestive cardiac failure, ischemic heart, liver, and renal disease. High hospital volume was associated with significant reductions in 30- (odds ratio (OR)=0.68; P=0.001) and 90-day mortality (OR=0.69; P=0.001). In a subset analysis of patients undergoing endoscopic intervention, hospital volume was identified as an important factor associated with mortality.CONCLUSIONS:This study provides evidence for the centralization of management of esophageal perforation to high volume centers with appropriate multi-disciplinary infrastructure to treat these complex patients.

Surgical Proficiency Gain and Survival After Esophagectomy for Cancer

PURPOSE We aimed to identify the presence and length of esophagectomy proficiency gain curves in terms of short- and long-term mortality for esophageal cancer. PATIENTS AND METHODS Patients who underwent esophagectomy for esophageal cancer between 1987 and 2010 with follow-up until 2014 were identified from a well-established, population-based, nationwide Swedish cohort study. Proficiency gain curves were created by using risk-adjusted cumulative sum analysis for 30-day, 90-day, 1-year, 3-year, and 5-year all-cause and disease-specific mortality measures. Similarly, the proficiency gain curves for lymph node harvest, resection margin status, and reoperation incidence were assessed as performance-contributing factors to the observed changes in long-term survival. RESULTS Esophagectomies in 1,821 patients with esophageal cancer were conducted by 139 surgeons. The change-point in proficiency gain curve for all-cause 30-day mortality was early, at 15 cases, when mortality decreased from 7.9% to 3.1% (P < .001). Later change-points, which ranged from 35 to 59 cases, were observed for 1-, 3- and 5-year mortality rates, for which all-cause mortality decreased from 34.9% to 27.7% (P = .011), from 47.4% to 41.5% (P = .049), and from 31.4% to 19.1% (P = .009), respectively. Similar change-points were observed in disease-specific mortality at 1 and 3 years. There was a continuous increase in lymph node harvest, which did not plateau. Also, change-points were observed for resection margin with tumor involvement at 17 cases, with a reduction from 20.9% to 15.2% (P = .004), and for reoperation rate at 55 cases, with a reduction from 12.6% to 5.0% (P < .001). CONCLUSION The gain of proficiency in esophagectomy for cancer is associated with measurable changes in short- and long-term mortality results. These findings indicate a need for structured national training and mentorship programs for esophageal cancer surgery.

National proficiency‐gain curves for minimally invasive gastrointestinal cancer surgery

Minimal access surgery for gastrointestinal cancer has short‐term benefits but is associated with a proficiency‐gain curve. The aim of this study was to define national proficiency‐gain curves for minimal access colorectal and oesophagogastric surgery, and to determine the impact on clinical outcomes.

Clinical validity of consultant technical skills assessment in the English National Training Programme for Laparoscopic Colorectal Surgery

The English National Training Programme for Laparoscopic Colorectal Surgery introduced a validated objective competency assessment tool to accredit surgeons before independent practice. The aim of this study was to determine whether this technical skills assessment predicted clinical outcomes.

Consensus on structured training curriculum for transanal total mesorectal excision (TaTME)

BackgroundThe interest and adoption of transanal total mesorectal excision (TaTME) is growing amongst the colorectal surgical community, but there is no clear guidance on the optimal training framework to ensure safe practice for this novel operation. The aim of this study was to establish a consensus on a detailed structured training curriculum for TaTME.MethodsA consensus process to agree on the framework of the TaTME training curriculum was conducted, seeking views of 207 surgeons across 18 different countries, including 52 international experts in the field of TaTME. The process consisted of surveying potential learners of this technique, an international experts workshop and a final expert’s consensus to draw an agreement on essential elements of the curriculum.ResultsAppropriate case selection was strongly recommended, and TaTME should be offered to patients with mid and low rectal cancers, but not proximal rectal cancers. Pre-requisites to learn TaTME should include completion of training and accreditation in laparoscopic colorectal surgery, with prior experience in transanal surgery. Ideally, two surgeons should undergo training together in centres with high volume for rectal cancer surgery. Mentorship and multidisciplinary training were the two most important aspects of the curriculum, which should also include online modules and simulated training for purse-string suturing. Mentors should have performed at least 20 TaTME cases and be experienced in laparoscopic training. Reviewing the specimens’ quality, clinical outcome data and entering data into a registry were recommended. Assessment should be an integral part of the curriculum using Global Assessment Scales, as formative assessment to promote learning and competency assessment tool as summative assessment.ConclusionsA detailed framework for a structured TaTME training curriculum has been proposed. It encompasses various training modalities and assessment, as well as having the potential to provide quality control and future research initiatives for this novel technique.

Laparoscopic Lavage Versus Primary Resection for Acute Perforated Diverticulitis: Review and Meta-analysis

Objective: To compare clinical outcomes after laparoscopic lavage (LL) or colonic resection (CR) for purulent diverticulitis. Background: Laparoscopic lavage has been suggested as an alternative treatment for traditional CR. Comparative studies to date have shown conflicting results. Methods: Electronic searches of Embase, Medline, Web of Science, and Cochrane databases were performed. Weighted mean differences (WMD) were calculated for effect size of continuous variables and pooled odds ratios (POR) calculated for discrete variables. Results: A total of 589 patients recruited from 3 randomized controlled trials (RCTs) and 4 comparative studies were included; 85% as Hinchey III. LL group had younger patients with higher body mass index and lower ASA grades, but comparable Hinchey classification and previous diverticulitis rates. No significant differences were noted for mortality, 30-day reoperations and unplanned readmissions. LL had higher rates of intraabdominal abscesses (POR = 2.85; 95% confidence interval, CI, 1.52–5.34; P = 0.001), peritonitis (POR = 7.80; 95% CI 2.12–28.69; P = 0.002), and increased long-term emergency reoperations (POR = 3.32; 95% CI 1.73–6.38; P < 0.001). Benefits of LL included shorter operative time, fewer cardiac complications, fewer wound infections, and shorter hospital stay. Overall, 90% had stomas after CR, of whom 74% underwent stoma reversal within 12-months. Approximately, 14% of LL patients required a stoma; 48% obtaining gut continuity within 12-months, whereas 36% underwent elective sigmoidectomy. Conclusions: The preservation of diseased bowel by LL is associated with approximately 3 times greater risk of persistent peritonitis, intraabdominal abscesses and the need for emergency surgery compared with CR. Future studies should focus on developing composite predictive scores encompassing the wide variation in presentations of diverticulitis and treatment tailored on case-by-case basis.