Defining global benchmarks in elective secondary bariatric surgery comprising conversional, revisional and reversal procedures

Objective

Management of poor response and of long-term complications after bariatric surgery (BS) is complex and under-investigated. Indications and types of reoperations vary widely and postoperative complication rates are higher compared to primary BS. Benchmarking uses best performance in a given field as reference point for improvement. Our aim was to define ‘‘best possible’’ outcomes for elective secondary BS.

Methods

The establishment of benchmarks in secondary BS followed a standardized methodology, based on recommendations of a Delphi consensus panel of experts. This multicenter study analyzed patients undergoing elective secondary BS in 18 high-volume centers on 4 continents from 06/2013 to 05/2019. Twenty-one outcome benchmarks were established in low-risk patients, defined as the 75th percentile of the median outcome values of the centers. Benchmark cases had no: previous laparotomy, diabetes, sleep apnea, cardiopathy, renal insufficiency, inflammatory bowel disease, immunosuppression, history of thromboembolic events, BMI>50kg/m2 or age>65 years. Descriptive statistics, multivariate logistic regression and data visualization were performed using the R software.

Results

Out of 44’884 elective bariatric procedures performed in the participating centers, 5’328 secondary BS cases were identified. The benchmark cohort included 3143 cases, mainly females (85%), aged 43.8±10 years, 8.4±5.3 years after primary BS, with a body mass index 35.2±7kg/m2. Main indications were insufficient weight loss (43%) and gastro-esophageal reflux disease/dysphagia (25%). 90-days postoperatively, 14.57% of benchmark patients presented ≥1 complication, mortality was 0.06% (n = 2). Significantly higher morbidity was observed in non-benchmark cases (OR 1.36) and after conversional or revisional procedures with gastrointestinal suture/stapling (OR 1.7). Benchmark cutoffs at 90-days postoperatively were ≤5.8% re-intervention and ≤8.8% re-operation rate. At 2-years (IQR 1-3) 15.6% of benchmark patients required a reoperation.

Conclusion

Secondary BS is safe, although postoperative morbidity exceeds the established benchmarks for primary BS. The excess morbidity is due to an increased risk of gastrointestinal leakage and higher need for intensive care. The considerable rate of tertiary BS warrants expertise and future research to optimize the management of non-success after BS.

Perspective: APOBEC mutagenesis in drug resistance and immune escape in HIV and cancer evolution

The apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like (APOBEC) mutational signature has only recently been detected in a multitude of cancers through next-generation sequencing. In contrast, APOBEC has been a focus of virology research for over a decade. Many lessons learnt regarding APOBEC within virology are likely to be applicable to cancer. In this review, we explore the parallels between the role of APOBEC enzymes in HIV and cancer evolution. We discuss data supporting the role of APOBEC mutagenesis in creating HIV genome heterogeneity, drug resistance, and immune escape variants. We hypothesize similar functions of APOBEC will also hold true in cancer.

Systematic review and simulation study of ignoring clustered data in surgical trials

BACKGROUND

Multiple surgical procedures in a single patient are relatively common and lead to dependent (clustered) data. This dependency needs to be accounted for in study design and data analysis. A systematic review was performed to assess how clustered data were handled in inguinal hernia trials. The impact of ignoring clustered data was estimated using simulations.

METHODS

PubMed, Embase and the Cochrane Library were reviewed systematically for RCTs published between 2004 and 2013, including patients undergoing unilateral or bilateral inguinal hernia repair. Study characteristics determining the appropriateness of handling clustered data were extracted. Using simulations, various statistical methods accounting for clustered data were compared with an analysis ignoring clustering by assuming 100 hernias, with a varying percentage of patients having bilateral hernias.

RESULTS

Of the 50 eligible trials including patients with bilateral hernias, 20 (40 per cent) did not provide information on how they dealt with clustered data and 18 (36 per cent) avoided clustering by assessing the outcome by patient and not by hernia. None of the remaining 12 trials (24 per cent) considered clustering in the design or analysis. In the simulations, ignoring clustering led to an increased type I error rate of up to 12 per cent and to a loss in power of up to 15 per cent, depending on whether the patient or the hernia was the randomization unit.

CONCLUSION

Clustering was rarely considered in inguinal hernia trials. The simulations underline the importance of considering clustering as part of the statistical analysis to avoid false-positive and false-negative results, and hence inappropriate study conclusions.

Differential binding affinity of mutated peptides for MHC class I is a predictor of survival in advanced lung cancer and melanoma

Background

Cancer mutations generate novel (neo-)peptides recognised by T cells, but the determinants of recognition are not well characterised. The difference in predicted class I major histocompatibility complex (MHC-I) binding affinity between wild-type and corresponding mutant peptides (differential agretopicity index; DAI) may reflect clinically relevant cancer peptide immunogenicity. Our aim was to explore the relationship between DAI, measures of immune infiltration and patient outcomes in advanced cancer.

Patients and methods

Cohorts of patients with advanced non-small-cell lung cancer (NSCLC; LUAD, n = 66) and melanoma (SKCM, n = 72) were obtained from The Cancer Genome Atlas. Three additional cohorts of immunotherapy treated patients with advanced melanoma (total n = 131) and NSCLC (n = 31) were analysed. Neopeptides and their clonal status were defined using genomic data. MHC-I binding affinity was predicted for each neopeptide and DAI values summarised as the sample mean DAI. Correlations between mean DAI and markers of immune activity were evaluated using measures of lymphocyte infiltration and immune gene expression.

Results

In univariate and multivariate analyses, mean DAI significantly correlated with overall survival in 3/5 cohorts, with evidence of superiority over nonsynonymous mutational and neoantigen burden. In these cohorts, the effect was seen for mean DAI of clonal but not subclonal peptides. In SKCM, the association between mean DAI and survival bordered significance (P = 0.068), reaching significance in an immunotherapy-treated melanoma cohort (P = 0.003). Mean DAI but not mutational nor neoantigen burden was positively correlated with independently derived markers of immune infiltration in both SKCM (P = 0.027) and LUAD (P = 0.024).

Conclusions

The association between mean DAI, survival and measures of immune activity support the hypothesis that DAI is a determinant of cancer peptide immunogenicity. Investigation of DAI as a marker of immunologically relevant peptides in further datasets and future clinical studies of neoantigen based immunotherapies is warranted.

Intratumoural evolutionary landscape of high-risk prostate cancer: the PROGENY study of genomic and immune parameters

BACKGROUND

Intratumoural heterogeneity (ITH) is well recognised in prostate cancer (PC), but its role in high-risk disease is uncertain. A prospective, single-arm, translational study using targeted multiregion prostate biopsies was carried out to study genomic and T-cell ITH in clinically high-risk PC aiming to identify drivers and potential therapeutic strategies.

PATIENTS AND METHODS

Forty-nine men with elevated prostate-specific antigen and multiparametric-magnetic resonance imaging detected PC underwent image-guided multiregion transperineal biopsy. Seventy-nine tumour regions from 25 patients with PC underwent sequencing, analysis of mutations, copy number and neoepitopes combined with tumour infiltrating T-cell subset quantification.

RESULTS

We demonstrated extensive somatic nucleotide variation and somatic copy number alteration heterogeneity in high-risk PC. Overall, the mutational burden was low (0.93/Megabase), but two patients had hypermutation, with loss of mismatch repair (MMR) proteins, MSH2 and MSH6. Somatic copy number alteration burden was higher in patients with metastatic hormone-naive PC (mHNPC) than in those with high-risk localised PC (hrlPC), independent of Gleason grade. Mutations were rarely ubiquitous and mutational frequencies were similar for mHNPC and hrlPC patients. Enrichment of focal 3q26.2 and 3q21.3, regions containing putative metastasis drivers, was seen in mHNPC patients. We found evidence of parallel evolution with three separate clones containing activating mutations of β-catenin in a single patient. We demonstrated extensive intratumoural and intertumoural T-cell heterogeneity and high inflammatory infiltrate in the MMR-deficient (MMRD) patients and the patient with parallel evolution of β-catenin. Analysis of all patients with activating Wnt/β-catenin mutations demonstrated a low CD8+/FOXP3+ ratio, a potential surrogate marker of immune evasion.

CONCLUSIONS

The PROGENY (PROstate cancer GENomic heterogeneitY) study provides a diagnostic platform suitable for studying tumour ITH. Genetic aberrations in clinically high-risk PC are associated with altered patterns of immune infiltrate in tumours. Activating mutations of Wnt/β-catenin signalling pathway or MMRD could be considered as potential biomarkers for immunomodulation therapies.

CLINICAL TRIALS.GOV IDENTIFIER

NCT02022371.

Surgical treatment of uncomplicated diverticulitis in Switzerland: comparison of population-based data over two time periods

AIM

The standard of care for acute uncomplicated diverticulitis used to be an elective colon resection after the second or third episode. This practice was replaced by a more conservative and individualized approach. This study investigates current surgical practice in the treatment of acute uncomplicated diverticulitis in Switzerland.

METHOD

Retrospective cross-sectional analysis of all hospital admissions due to uncomplicated diverticulitis in Switzerland using prospectively collected data from the Swiss Federal Statistical Office in two periods: 2004/2005 and 2010/2011. Treatment options were compared between the two periods with adjustment for baseline characteristics of patients and treating institutions.

RESULTS

A total of 24 497 patients (11 835 in 2004/2005; 12 662 in 2010/2011) were admitted to Swiss hospitals for uncomplicated diverticulitis. Between periods, the incidence increased from 81 to 85 admissions per 10⁵ inhabitants per year. Elective admissions decreased from 46% (n = 5490) to 34% (n = 4294). The unadjusted resection rate decreased from 40% (n = 4730) to 34% (n = 4308). In the adjusted analysis, inpatients were more likely to have a resection in 2010/2011 than in 2004/2005 [odds ratio of 1.38 (95% confidence interval 1.25-1.54)]. In addition, private insurance, elective mode of admission and younger age increased the odds for resection while there was no evidence of an association between resection and either gender or comorbidities.

CONCLUSION

The probability of colon resection for patients hospitalized with acute uncomplicated diverticulitis increased between periods while the overall number of colon resections declined. A change of practice expected given the paradigm shift towards conservative treatment could not be confirmed in this analysis.

Towards a situation-and-user-aware multi-modal motorized toilet system to assist older adults with disabilities: A user requirements study

In the recent decades state of the art technologies appeared in many areas to assist older adults with disabilities. However, one very essential activity of daily life, the toileting remained without any relevant development. The iToilet project of the European Union focuses on the development of an intelligent and motorized toilet system to enable independent toilet use for older adults with disabilities. To begin the development, the user requirements of end-users were assessed by means of focus group interviews and questionnaires. The survey was conducted in Austria and Hungary with the participation of 74 persons in total (41 subjects with movement disorders, 21 caregivers and 12 healthcare managers). From the interviews, the ranking of functions and features based on the number of their mentions was derived. The raw ranking was modulated by the average ratings from the questionnaires that resulted in the final list of priorities. Our results suggest that a safe and intelligent motorized toilet system should have foldable handrails on both sides (especially for wheelchair users), motorized height and tilt adjusting mechanism for the toilet bowl, fixed toilet paper holder on both sides and emergency recognition with call function. Simple operation, storage and retrieval of user specific settings including bowl height, and user identification were also deemed as very important features, while the possibility to control functions with gestures was valued rather low.

Reversal after Hartmann's procedure in patients with complicated sigmoid diverticulitis

AIM

Hartmann's procedure (HP) is commonly used for the emergency treatment of complicated sigmoid diverticulitis (CSD). It is intended to restore intestinal continuity; however, in practice, reversal is not carried out in all patients. It is important to know the frequency of reversal and the impact of patient-related factors on the decision for reversal.

METHOD

A retrospective study was conducted on all patients who underwent HP for CSD at a tertiary referral hospital between 1 May 2005 and 31 December 2010. We assessed the frequency of reversal over time and the prognostic factors affecting the decision for reversal.

RESULTS

Of 67 patients [median age 76 (interquartile range: 68-81) years] who had HP for CSD, 28 (42%) underwent reversal. The cumulative incidence of reversal after 48 weeks was 48% (95% CI: 36-62%). Reversal was less likely in elderly patients [hazard ratio (HR) per decade increase = 0.43; 95% CI: 0.26-0.71], with cardiac insufficiency or coronary heart disease (HR = 0.60; 95% CI: 0.26-1.40) and with preoperative immunosuppression or chemotherapy (HR = 0.31; 95% CI: 0.07-1.33). There was no apparent effect of these factors on mortality.

CONCLUSION

Approximately half of the patients having HP for CSD undergo reversal within 48 weeks of the initial operation. The finding that age, cardiac or coronary heart disease and preoperative immunosuppression or chemotherapy have an impact on the decision for reversal is relevant to healthcare professionals and patients.

Claudin-2-mediated cation and water transport share a common pore

AIM

Claudin-2 is a tight junction protein typically located in 'leaky' epithelia exhibiting large paracellular permeabilities like small intestine and proximal kidney tubule. Former studies revealed that claudin-2 forms paracellular channels for small cations like sodium and potassium and also paracellular channels for water. This study analyses whether the diffusive transport of sodium and water occurs through a common pore of the claudin-2 channel.

METHODS

Wild-type claudin-2 and different claudin-2 mutants were expressed in MDCK I kidney tubule cells using an inducible system. Ion and water permeability and the effect of blocking reagents on both were investigated on different clones of the mutants.

RESULTS

Neutralization of a negatively charged cation interaction site in the pore with the mutation, D65N, decreased both sodium permeability and water permeability. Claudin-2 mutants (I66C and S68C) with substitution of the pore-lining amino acids with cysteine were used to test the effect of steric blocking of the claudin-2 pore by thiol-reactive reagents. Addition of thiol-reactive reagents to these mutants simultaneously decreased conductance and water permeability. Remarkably, all experimental perturbations caused parallel changes in ion conductance and water permeability, disproving different or independent passage pathways.

CONCLUSION

Our results indicate that claudin-2-mediated cation and water transport are frictionally coupled and share a common pore. This pore is lined and determined in permeability by amino acid residues of the first extracellular loop of claudin-2.

On the Prototyping of an ICT-Enhanced Toilet System for Assisting Older Persons Living Independently and Safely at Home

Standard toilets often do not meet the needs of a significant number of older persons and persons with disabilities. The EU funded iToilet project aims at design and development of a new type of ICT enhanced modular toilet system which shall be able to support autonomy, dignity and safety of older persons living at home. Methodologically the project started with gathering user requirements by means of questionnaires, interviews and focus group discussion involving a total of 74 persons, thereof 41 subjects with movement disorders (primary users), 21 caregivers (secondary users) and 12 healthcare managers (tertiary users). Most important wishes were bilateral removable handrails, height and tilt adjustment, emergency detection, simplicity. In parallel to the ongoing technical development participatory design activities have been carried out at user test sites in order to continuously involve users into the design process and to allow quick feedback with regards to early prototype parts. The project currently is working on the finalization of the first prototype ready to enter the lab trial stage in spring 2017. The experiences will be used for redesigning a prototype 2 which is planned to be tested in real life settings early 2018.

Mitigating effect of EUK-207 on radiation-induced cognitive impairments

The brain could be exposed to irradiation as part of a nuclear accident, radiological terrorism (dirty bomb scenario) or a medical radiological procedure. In the context of accidents or terrorism, there is considerable interest in compounds that can mitigate radiation-induced injury when treatment is initiated a day or more after the radiation exposure. As it will be challenging to determine the radiation exposure an individual has received within a relatively short time frame, it is also critical that the mitigating agent does not negatively affect individuals, including emergency workers, who might be treated, but who were not exposed. Alterations in hippocampus-dependent cognition often characterize radiation-induced cognitive injury. The catalytic ROS scavenger EUK-207 is a member of the class of metal-containing salen manganese (Mn) complexes that suppress oxidative stress, including in the mitochondria, and have been shown to mitigate radiation dermatitis, promote wound healing in irradiated skin, and mitigate vascular injuries in irradiated lungs. As the effects of EUK-207 against radiation injury in the brain are not known, we assessed the effects of EUK-207 on sham-irradiated animals and the ability of EUK-207 to mitigate radiation-induced cognitive injury. The day following irradiation or sham-irradiation, the mice started to receive EUK-207 and were cognitively tested 3 months following exposure. Mice irradiated at a dose of 15Gy showed cognitive impairments in the water maze probe trial. EUK-207 mitigated these impairments while not affecting cognitive performance of sham-irradiated mice in the water maze probe trial. Thus, EUK-207 has attractive properties and should be considered an ideal candidate to mitigate radiation-induced cognitive injury.

Heller oesophagomyotomy as treatment for achalasia after gastric bypass for morbid obesity

When achalasia is unrecognised during the preoperative phase in patients who have undergone bariatric procedures, a late Heller oesophagomyotomy may be used as the treatment modality to prevent the development of megaoesophagus. We present the case of a 66-year-old man with achalasia 3 years after a Roux-en-Y gastric bypass procedure.

Claudin-2 as a mediator of leaky gut barrier during intestinal inflammation

The epithelial tight junction determines the paracellular water and ion movement in the intestine and also prevents uptake of larger molecules, including antigens, in an uncontrolled manner. Claudin-2, one of the 27 mammalian claudins regulating that barrier function, forms a paracellular channel for small cations and water. It is typically expressed in leaky epithelia like proximal nephron and small intestine and provides a major pathway for the paracellular transport of sodium, potassium, and fluid. In intestinal inflammation (Crohn's disease, ulcerative colitis), immune-mediated diseases (celiac disease), and infections (HIV enteropathy), claudin-2 is upregulated in small and large intestine and contributes to diarrhea via a leak flux mechanism. In parallel to that upregulation, other epithelial and tight junctional features are altered and the luminal uptake of antigenic macromolecules is enhanced, for which claudin-2 may be partially responsible through induction of tight junction strand discontinuities.

Laparoscopic treatment of intrasplenic pancreatic pseudocyst

INTRODUCTION

Pseudocyst formation commonly follows pancreatitis, but erosion into the spleen is rare and potentially life threatening. We report a case of an intrasplenic pancreatic pseudocyst treated laparoscopically with distal pancreatectomy and splenectomy.

METHODS

A 50 year old male with a history of chronic alcoholic pancreatitis, presented with abdominal pain for 3 months, worsening over the past several days. A CT scan showed a broad 9 cm subcapsular fluid collection suspicious for an intra-splenic pseudocyst. The patient underwent laparoscopic distal pancreatectomy and splenectomy.

RESULTS

There were no intraoperative complications and the patient was discharged on day 8. The final pathology revealed a benign cystic lesion measuring 9 x 6 x 3 cm that was not communicating with the pancreatic duct, and 2 smaller pseudocysts in the pancreatic body and tail. A previous scan did not reveal any abnormalities in the spleen, and showed the other pancreatic pseudocysts. At 8 month follow up the patients was symptom free, with no new pseudocysts.

CONCLUSIONS

Splenic parenchyma involvement is an unusual complication of pancreatic pseudocyst. The optimal treatment is controversial. Percutaneous drainage carries a high recurrence rate and risk of hemorrhage. Open surgery is effective, but associated with significant morbidity. Laparoscopy offers an effective method of treatment without the potential complication of a large abdominal incision.

Outcomes after laparoscopic conversion of failed adjustable gastric banding to sleeve gastrectomy or Roux-en-Y gastric bypass

Background

Laparoscopic adjustable gastric banding (LAGB) has a high incidence of long-term complications and failures. The best procedure to handle these failures and the optimal number of stages in such cases is still controversial. The aim of this retrospective study was to compare the results of conversions of LAGB to either laparoscopic sleeve gastrectomy (LSG) or laparoscopic Roux-en-Ygastric bypass (LRYGB) in failed LAGB using a single-stage approach.

Methods

All patients who underwent conversion from LAGB to either LRYGB or LSG between January 2005 and March 2012 were included in the study. Early and late complications were reviewed. The percentage excess weight loss (%EWL) between the two groups was compared at 3, 6, 12 and 24 months of follow-up.

Results

Fifty-nine patients, 11 men and 48 women, were included in the study. The most frequent indication was insufficient weight loss or weight regain (non-responders group), in 44 patients (75 per cent); 15 patients had a revision for complicated LAGB. The early complication rate in the non-responders group was 7 per cent (3 of 44 patients), compared with 13 per cent (2 of 15) in the complicated LAGB group. Mean(s.d.) %EWL in the non-responders group was 55(22) per cent in patients converted to LRYGB and 28(25) in those converted to LSG (P = 0·001).

Conclusion

LRYGB and LSG are both safe and feasible options for failed or complicated LAGB. In the non-responders group, %EWL was superior for conversion to LRYGB. The surgical morbidity rate was highest in patients having revision for band complications.

Basic laparoscopic training using the Simbionix LAP Mentor: setting the standards in the novice group

BACKGROUND

Virtual reality devices are becoming the backbone for laparoscopic training in surgery. However, without knowledge of the achievable metrics of basic training within the trainee group, these simulators cannot be used effectively. Currently, no validated task metrics of the performance of larger trainee groups are available.

STUDY DESIGN

From April 2004 to December 2009, we collated an extensive prospective database using the Simbionix LAP Mentor (Simbionix USA, Cleveland, Ohio) for basic laparoscopic training of novice surgeons. This database was used to determine benchmarks for basic skill exercises and procedural tasks that combine stimulus to improve and feasibility with acceptance of the training program and the goal to train for safe surgery.

RESULTS

In all, 18,996 task performances of 286 novice trainees were analyzed. For the basic skill exercises, the total time for correct execution ranged between 45 seconds for basic skill 3 (eye-hand coordination) and 269 seconds for basic skill 9 (object placement). For the procedural tasks, the total time for correct execution ranged between 68 seconds for procedural task 1 (clipping and cutting) and 256 seconds for procedural task 3 (dissection). The total time to task completion depended mainly on right instrument path length with high correlation to left instrument path length. Learning curve analyses of the 4 procedural tasks demonstrated performance plateaus after 10-15 repetitions. Most complications occurred during the initial repetitions of the respective task. The best quartile of performances was chosen as peer group benchmark because it provides sufficient stimulus for improvement without discouraging trainees, thus enhancing adherence to the training program. The benchmark for safety and accuracy parameters was set at a predefined level of 95% correct execution.

CONCLUSIONS

As experience with virtual reality (VR) training is growing, curricula must be based on benchmarks for efficient training derived from large trainee groups to optimize use of the still costly simulators. Safety parameters should be included in trainee assessment. We share a set of metrics that take into account both performance and feasibility for basic laparoscopic training of surgical novices using the Simbionix LAP Mentor.

Surveillance of surgical site infections by surgeons: biased underreporting or useful epidemiological data?

Surgical site infections (SSIs) significantly increase post-operative morbidity and mortality. SSI surveillance is an established monitoring tool and reduces SSI rates. The purpose of this study was to compare prospective in-hospital SSI surveillance (I) by the surgical staff and (II) additionally by an infection control team (ICT). The reference method (III) was defined by data generated by the surgical team, supplemented by the ICT and completed by post-discharge surveillance with a post-operative follow-up of one year representing the sum of all available resources. During 24 months, all consecutive inpatient procedures (N=6283) were prospectively recorded by the surgical staff until patients' discharge (I). SSI rates were compared with the surveillance performed by the ICT (II) and with the reference method (III). The overall SSI rate (reference method) was 4.7% (N=293), of which 187 (63.8%) were detected in-hospital and 106 (36.2%) after discharge. (I) The surgical staff detected 91/187 (48.7%) of in-hospital SSIs [91/293 (31.0%) of the reference], (II) the ICT an additional 96/187 (51.3%) during hospitalisation [96/293 (32.8%) of the reference]. Further cross-checking as performed in the visceral surgery department increased the surgeons' detection rate (I) to 59/105 (56.2%) of in-hospital SSIs [59/147 (40.1%) of the reference]. SSI surveillance by the surgical staff detects almost half of all in-hospital SSIs and has the potential to increase the detection rate by simple interventions such as cross-checking. Such a relatively inexpensive surveillance system is an option for hospitals without an ICT or for low risk surgical procedures. Moreover, trends in SSI rates can easily be detected, allowing early intervention.

[Preoperative assessment in visceral surgery]

The purpose of preoperative assessment is to evaluate the patient's health status, to address known or unidentified co-morbidities and to perform adequate complementary exams if necessary. On the other hand, it allows to prepare and protect the patient in order to reduce perioperative risk. The assessment consists of patient's history and physical examination, both focusing on cardiovascular and respiratory assessment. Complementary exams have to be chosen selectively depending on the patient's risk factors and the type of surgery. They are indicated if their result leads to a potential patient's benefit only, either by a modification in anesthetic and/or surgical management or by introduction of a pharmacological strategy, adequate and maximal if necessary, especially for cardioprotection.

Esophageal motility disorders in the morbidly obese population

BACKGROUND

Most studies investigating esophageal motility among the morbidly obese have focused on the relationship between lower esophageal sphincter (LES) pressure and gastroesophageal reflux disease (GERD). Very few studies in the literature have examined motility disorders among the morbidly obese population in general outside the context of GERD. This study aimed to determine the prevalence of esophageal motility disorders in obese patients selected for bariatric surgery.

METHODS

A total of 116 obese patients (81 women and 35 men) selected for laparoscopic gastric banding underwent manometric evaluation of their esophagus from January to March 2003. Tracings were retrospectively reviewed for the end points of LES resting pressure, LES relaxation, and esophageal peristalsis.

RESULTS

The study patients had a body mass index (BMI) of 42.9 kg/m2, and a mean age of 48.6 years. The following abnormal manometric findings were demonstrated in 41% of the patients: nonspecific esophageal motility disorders (23%), nutcracker esophagus (peristaltic amplitude >180 mmHg) (11%), isolated hypertensive LES pressure (>35 mmHg) (3%), isolated hypotensive LES pressure (<12 mmHg) (3%), diffuse esophageal spasm (1%), and achalasia (1%). Only one patient with abnormal esophageal motility reported noncardiac chest pain.

CONCLUSIONS

Despite a high prevalence of esophageal dysmotility in our morbidly obese study population, there was a conspicuous absence of symptoms. Although the patients in this study were not directly questioned with regard to esophageal symptoms, several studies in the literature support our conclusion.

Can skills assessment on a virtual reality trainer predict a surgical trainee’s talent in laparoscopic surgery?

BACKGROUND

A number of studies have investigated several aspects of feasibility and validity of performance assessments with virtual reality surgical simulators. However, the validity of performance assessments is limited by the reliability of such measurements, and some issues of reliability still need to be addressed. This study aimed to evaluate the hypothesis that test subjects show logarithmic performance curves on repetitive trials for a component task of laparoscopic cholecystectomy on a virtual reality simulator, and that interindividual differences in performance after considerable training are significant. According to kinesiologic theory, logarithmic performance curves are expected and an individual's learning capacity for a specific task can be extrapolated, allowing quantification of a person's innate ability to develop task-specific skills.

METHODS

In this study, 20 medical students at the University of Basel Medical School performed five trials of a standardized task on the LS 500 virtual reality simulator for laparoscopic surgery. Task completion time, number of errors, economy of instrument movements, and maximum speed of instrument movements were measured.

RESULTS

The hypothesis was confirmed by the fact that the performance curves for some of the simulator measurements were very close to logarithmic curves, and there were significant interindividual differences in performance at the end of the repetitive trials.

CONCLUSIONS

Assessment of perceptual motor skills and the innate ability of an individual with no prior experience in laparoscopic surgery to develop such skills using the LS 500 VR surgical simulator is feasible and reliable.

Extraanatomic lateral reconstruction to the popliteal vessels

OBJECTIVES

To describe the lateral approach to the popliteal artery in reconstructions after soft tissue sarcoma resection in the thigh.

DESIGN

Case reports. Subjects Four patients with soft tissue sarcoma.

METHODS

Extraanatomic reconstruction of the resected artery and vein in the medial part of the thigh was performed. Vessel reconstruction was performed before tumor resection to avoid leg ischemia.

RESULTS

In all four patients the artery was replaced by using the contralateral saphenous vein, while the femoral vein was replaced in two cases using e-PTFE. Post-operative complications included one large lymphatic collection and a deep wound infection. Arterial primary graft patency was 100% after 1-7 years. Patency of the e-PTFE-venous graft was 0% without further consequences.

CONCLUSIONS

The extraanatomic lateral replacement of the vessels in the thigh is an elegant method in difficult vascular reconstructions after soft tissue sarcoma resection or debridement for deep vascular infections.

[Function of bestrophin]

Clarification of the function of bestrophin, the gene product of VMD2, establishes a basis for the understanding of the pathomechanisms leading to Best's vitelliform macular degeneration. Studies of heterologously expressed bestrophin showed that bestrophin can function as a Cl(-) channel. All four known bestrophins were found to display Cl(-) channel activity. A loss in Cl(-) channel function would elegantly explain the development of the leading symptom for Best's disease, the reduction of the light peak amplitude in the patient's electro-oculogram. However, there are still gaps in the chain of evidence demonstrating that bestrophin is a Cl(-) channel, and this hypothesis is inconsistent with newly published follow-up observations. In an alternative hypothesis bestrophin appears as a regulator of voltage-dependent Ca(2+) channels assuming an indirect involvement of bestrophin in the generation of the light peak. Further studies on either bestrophin-deficient mice or transgenic mice will show that either one of the hypotheses is right or maybe both will be proven correct, showing bestrophin as a Cl(-) channel and Ca(2+) channel regulator.

Effects of colonoscopy on intracranial pressure: observation in a large animal model

BACKGROUND AND STUDY AIMS

Increased intra-abdominal pressure has been associated with increased intracranial pressure. Bowel insufflation during colonoscopy may increase the intra-abdominal pressure. It was hypothesized that colonoscopy may be associated with intracranial pressure elevation subsequent to an elevation in intra-abdominal pressure.

MATERIALS AND METHODS

Colonoscopy was carried out in seven anesthetized pigs, and the colonoscope was advanced up to 60 cm from the anal verge. Insufflation was used to allow safe advancement of the colonoscope and to allow visualization of the colon, in the same way as in the procedure performed in humans. Intra-abdominal pressure was measured by determining the hydrostatic pressure in the urinary bladder. A subarachnoid screw was used to monitor intracranial pressure. The mean arterial blood pressure and intra-abdominal venous pressure were directly monitored via the femoral vessel access; all parameters were recorded before and during colonoscopy.

RESULTS

A statistically significant elevation in intracranial pressure was demonstrated during colonoscopy. The average increase in intracranial pressure was 3.1 mm Hg. The intra-abdominal pressure and intra-abdominal venous pressure were also significantly elevated during the procedure.

CONCLUSIONS

Colonoscopy may increase intracranial pressure due to an increase in intra-abdominal pressure. This may have clinical implications when colonoscopy is conducted in patients with brain pathology associated with high intracranial pressure.

Peritoneal Mesothelioma after Environmental Asbestos Exposure

Mesothelioma are primary malignant neoplasms of the serous membranes. They usually involve the pleura and rarely the pericardium, the peritoneum and the tunica vaginalis testis. About 90% are associated with exposure to asbestos. The exposure is generally occupational, an environmental inhalation of asbestos and asbestiform fibers in areas in Turkey has been observed and presents a major health problem. This report of a patient from Anatolia with peritoneal mesothelioma after environmental exposure outlines the importance of considering this pathology in the differential diagnosis of a Turkish patient presenting with ascites.

Technical considerations in laparoscopic resection of gastric neoplasms

BACKGROUND

The purpose of this study was to determine the use of different laparoscopic approaches in the management of gastric neoplasms based on tumor type and location.

METHODS

We retrospectively reviewed the records of seven patients (3 men and 4 women) with 11 gastric lesions who were referred to our facility between March 2000 and October 2001 for laparoscopic excision of gastric neoplasms.

RESULTS

Two patients had gastrointestinal stromal lesions (3 lesions); two patients had hyperplastic polyps (3 lesions); one patient had carcinoid tumor (2 lesions); one patient had a carcinoma in situ and an adenoma; and one patient had an ectopic pancreas. Extraluminal laparoscopic wedge resection was used in four patients with lesions at the anterior gastric wall or along the lesser or greater curvature. Intragastric excision was used in two patients with small posterior wall lesions, and a transgastrotomy approach was used in one patient with a posterior wall lesion that could not be removed by the intragastric approach. All the lesions were completely excised with clear margins. The median hospital stay was 3 days. Complications developed in two patients. One patient presented with a perforated ulcer 2 weeks after surgery, and a second patient had postoperative pyloric edema that resolved with conservative treatment.

CONCLUSIONS

The use of different laparoscopic approaches based on gastric neoplasm type and location facilitates tumor access and resection.

[Laparoscopic and conventional cholecystectomy. Didactic concept for training and introduction of laparoscopic cholecystectomy and preventing complications]

AIM

This study has assessed the suitability of an educational concept for the introduction and training of laparoscopic cholecystectomy, a newly established operational procedure, within an university teaching hospital with a large number of surgeons.

PATIENTS AND METHODOLOGY

Since introduction of the first laparoscopic cholecystectomy all cholecystectomies were prospectively assessed over a period of two years (from May 1990 till May 1992). The educational concept applied was such that a given surgeon would first receive training from an instructor for 15 procedures and then assume responsibility for instruction of a subsequent trainee.

RESULTS

In two years 355 patients underwent cholecystectomy. 60% of the operations were performed laparoscopically and 40% of the operations performed openly. During the two year period 13 surgeons were trained in the new technique, with an average of 16 operations per surgeon. Throughout the introductory phase there were no serious complications, and in particular no damage to the bile duct.

DISCUSSION

The advantage of this introductory training phase has repeatedly been subject of discussion in the literature. In the meanwhile guidelines from specialist bodies and national institutions exist for regulating the education of new surgical techniques. In the past few years introduction to new techniques has gradually shifted toward training on the skill-stations and virtual reality trainers.

CONCLUSION

The described educational concept for the introduction and training of laparoscopic cholecystectomy has been well approved and accepted since the early 90's.

Determination of hemoglobin levels in the finger using near infrared spectroscopy

We previously demonstrated that near-infrared spectroscopy can be used to measure blood flow. The spectrum of blood is dominated by hemoglobin. Therefore, it should be possible to determine the concentration of hemoglobin in tissue using near-infrared transmittance. We attempted to do this in the finger using a unique handheld multiple wavelength spectrophotometer. We took samples from 73 subjects and performed repeat measurements in several subjects. Hemoglobin level was determined at the time of near-infrared measurement. We performed correlation analysis between the hemoglobin values and the absorbance values. There was a strong correlation between hemoglobin levels and the 14 wavelengths (r = 0.738, n = 121, SEE = 1.7). We categorized the patients by hemoglobin level as either normal (12-16 g/dl), mildly anemic (10-12 g/dl), or moderately anemic (<10 g/dl). There were 21 patients in the low hemoglobin group, 29 in the middle range, and 23 in the normal range. The mean hemoglobin levels were 8.4 +/- 0.3 g/dl for the low group, 10.9 +/- 0.1 g/dl for the mildly anemic group, and 13.8 +/- 0.3 g/dl for the group with normal hemoglobin. There was a clear separation of absorbance values among the three groups. The major differences seen were in the midrange of the spectrum. It is encouraging that this first study of hemoglobin measurement yielded data permitting a discrimination of hemoglobin levels. It is hoped that future refinements will lead eventually to a non-invasive technique for the measurement of blood hemoglobin concentration.

Context effects in forensic science: a review and application of the science of science to crime laboratory practice in the United States

This article discusses the phenomenon of "context effects" by reviewing the findings and practices of a range of scientific fields, including astronomy, physics, biology, medicine, and especially the relevant research and theory from psychology. Context information, such as expectations about what one is supposed to see or conclude, has been found to have a small but relentless impact on human perception, judgment, and decision-making. The article then considers the vulnerability of forensic science practice to context effects, and concludes by suggesting that forensic science adopt practices familiar in other fields of scientific work, in particular blind or double-blind testing and also the use of evidence line-ups.

Laparoscopic total mesorectal excision

After total mesorectal excision for rectal cancer was introduced in 1982, local recurrence rates decreased to 5%. These results were found to be reproducible; therefore, the technique became standard for the treatment of rectal cancer. Laparoscopic surgery for curable colorectal malignancy is still considered investigational. Indeed, the United States National Cancer Institute (NCI) trial excludes rectal carcinoma. The application of laparoscopy to rectal carcinoma must compete with total mesorectal excision, which has obtained favorable results in the last decade. In this review, we assess the adequacy of laparoscopic total mesorectal excision, describe the techniques (both anterior resection and abdominoperineal resection), and discuss their potential advantages.

Meta-analytic methods, the Rorschach, and the MMPI

In response to concerns described by H. N. Garb, J. M. Wood, M. T. Nezworski, W. M. Grove, and W. J. Stejskal (2001), the authors present the weighted and unweighted means and medians of the effect sizes obtained by J. B. Hiller, R. Rosenthal, R. F. Bornstein, D. T. R. Berry, and S. Brunell-Neuleib (1999). These indices of central tendency are presented separately for Minnesota Multiphasic Personality Inventory (MMPI) and Rorschach effect sizes, both for all the studies in the meta-analysis and for a 10% trimmed sample designed to obtain more robust estimates of central tendency. The variability of these 4 indices is noticeably greater for the MMPI than for the Rorschach. Meta-analysts must compute, compare, and evaluate a variety of indices of central tendency, and they must examine the effects of moderator variables. The authors also comment briefly on the use of phi versus kappa, combining correlated effect sizes and possible hindsight biases.

Intestinal ischemia after bushmaster (Lachesis muta) snakebite--a case report

After a snakebite by the Costa Rican bushmaster Lachesis stenophrys, a 64-year-old patient developed cardiovascular shock and coagulopathy. After intensive care and antivenom treatment, he was discharged after 4 days but had to be hospitalised again 3 days later because of abdominal pain and bowel obstruction. An emergency laparotomy revealed a necrotic ileum and caecum, and an obstruction of the superior mesenteric artery. Until now, this type of intestinal ischemic complication after a snakebite has not been reported in the literature. The effects of bushmaster venom are discussed.

[Post-traumatic pancreatic pseudocyst in a child]

Pancreatic pseudocysts are rare in children. Traumatic injury accounts for 80% of the cases. We present the case of a pancreatic injury with pseudocyst formation in a child and discuss the initial management of pancreatic injury as well as the treatment of pseudocyst formation in children.

Athletes with lower limb ischaemia

The case of a young healthy sportsman and acute exacerbation of chronic infragenicular pain is presented. Further investigation revealed an obstruction of the tibiofibular trunk due to an osteochondroma, arising from the fibula, which was immediately resected. Osteochondroma is observed in 1-2% of the population and may present with vascular complications. In young patients and athletes, leg pain may be of vascular origin due to an entrapment or compression and should always be considered.

Meta-analytic methods, the Rorschach, and the MMPI

In response to concerns described by H. N. Garb, J. M. Wood, M. T. Nezworski, W. M. Grove, and W. J. Stejskal (2001), the authors present the weighted and unweighted means and medians of the effect sizes obtained by J. B. Hiller, R. Rosenthal, R. F. Bornstein, D. T. R. Berry, and S. Brunell-Neuleib (1999). These indices of central tendency are presented separately for Minnesota Multiphasic Personality Inventory (MMPI) and Rorschach effect sizes, both for all the studies in the meta-analysis and for a 10% trimmed sample designed to obtain more robust estimates of central tendency. The variability of these 4 indices is noticeably greater for the MMPI than for the Rorschach. Meta-analysts must compute, compare, and evaluate a variety of indices of central tendency, and they must examine the effects of moderator variables. The authors also comment briefly on the use of phi versus kappa, combining correlated effect sizes and possible hindsight biases.

[Video-laparoscopic placement of adjustable gastric banding (lap-band) in the treatment of morbid obesity. Preliminary results after 407 interventions]

INTRODUCTION

Morbid obesity is the most frequent nutritional disorder in developed countries. Bariatric surgery is one option for the definitive treatment of this disorder. We present 407 patients who underwent implantation of adjustable silicone gastric banding. Ninety-four percent of the patients were satisfied with the procedure and its results.

MATERIAL AND METHOD

We performed a retrospective study in the Surgery Department of the Nordwestkrankenhaus teaching hospital of the University of Frankfurt. From April 1996 to January 2000 we performed laparoscopic placement of adjustable silicone gastric banding in 407 patients, using Kuzmak's technique. Mean body mass index was 49.1 and mean weight was 139.2 kg. We describe the patient selection method and provide a detailed description of the technique and its possible problems.

RESULTS

There was no operative or postoperative mortality. None of the patients required conventional surgery. Mean operating time was 62 minutes (including operating times during the learning period). Mean hospital stay was 5 days. We performed 24 (5,89%) reinterventions: 11 for displacement, 2 for erosion, 4 for infection of the reservoir, 2 due to review of the reservoir to prevent penetration and 4 due to dilatations of the pouch (changing the banding from a retrogastric to a retroesophageal position); one patient requested removal of the banding. Follow-up was performed at months 1, 6, 9 and 12. Mean weight loss was 28 kg at 6 months and 54 kg at 1 year. Mean weight loss in patients followed-up for 2 years was 58 kg. A total of 94.9% of the patients were satisfied with the procedure.

CONCLUSIONS

Laparoscopic implantation of adjustable gastric banding (Lap-Band) combines the aims of conventional gastroplasty with the advantages of laparoscopic surgery in terms of postoperative morbidity and minimal invasiveness.

The relationship of depression and stressors to immunological assays: a meta-analytic review

This is a broad meta-analysis of the relations of both depression and stressors to immunological assays. The number of study samples (greater than 180) and measures (greater than 40) is much more extensive than any so far. Analyses are done by both fixed and random effects. By a fixed-effects analysis, both major depression and naturally occurring acute stressors are associated with (1) an overall leukocytosis, (2) mild reductions in absolute NK-cell counts and relative T-cell proportions, (3) marginal increases in CD4/CD8 ratios, and (4) moderate decreases in T- and NK-cell function. However, the degree of heterogeneity of the studies' results raises questions about their robustness. Therefore, we also did the first random effects analysis to estimate what is likely to appear in future studies. For depression, the analysis showed the immunological correlates included (1) an overall leukocytosis, manifesting as a relative neutrophilia and lymphoenia; (2) increased CD4/CD8 ratios; (3) increased circulating haptoglobin, PGE(2), and IL-6 levels; (4) reduced NK-cell cytotoxicity; and (5) reduced lymphocyte proliferative response to mitogen. For stressors, the random effects analysis showed that future studies are likely to find the following effects: (1) an overall leukocytosis, manifesting as an absolute lymphocytosis; (2) alterations in cytotoxic lymphocyte levels, CD4/CD8 ratios, and natural killer cell cytotoxicity with the direction of change depending on the chronicity of the stressor; (3) a relative reduction of T-cell levels; (3) increased EBV antibody titers; (4) reduced lymphocyte proliferative response and proportion of IL-2r bearing cells following mitogenic stimulation; and (5) increased leukocyte adhesiveness. The random-effects analysis revealed that for both major depression and naturally occurring stressors the following effects are shared: leukocytosis, increased CD4/CD8 ratios, reduced proliferative response to mitogen, and reduced NK cell cytotoxicity. The implications for these findings for disease susceptibility and the pathophysiology of these conditions is discussed.