Andrew Wan

Expression and function of the K+ channel KCNQ genes in human arteries

BACKGROUND AND PURPOSE KCNQ‐encoded voltage‐gated potassium channels (Kv7) have recently been identified as important anti‐constrictor elements in rodent blood vessels but the role of these channels and the effects of their modulation in human arteries remain unknown. Here, we have assessed KCNQ gene expression and function in human arteries ex vivo.

Staple line reinforcement during laparoscopic sleeve gastrectomy: Does it affect clinical outcomes?

Although laparoscopic sleeve gastrectomy (LSG) is safe and efficacious treatment for morbid obesity, this procedure is associated with major staple line complications including leakage and bleeding. Staple-line reinforcement (SLR) either through suturing or buttressing with biological or synthetic material has been suggested as a method to prevent these complications. A Best Evidence Topic was constructed to address the question of whether SLR reduced these and other complications. MEDLINE, EMBASE and CINAHL searches up to October 2012 returned 97 unique results, of which nine (one meta-analysis, two randomised controlled trials (RCTs), six prospective cohort studies) provided the best evidence to answer this clinical question. We conclude that current evidence suggests that staple-line reinforcement reduces the incidence of leakage and postoperative complications than non-reinforcement but does not significantly reduce bleeding complications. However, we cannot as yet recommend staple-line reinforcement as the strength of the presented evidence is limited by the variable quality of the published studies. The full-length publication of several abstracts of randomised, controlled trials presented at various recent conferences is awaited. This may provide more data on the effect of staple-line reinforcement on other outcomes largely neglected by currently available studies.

Sleeve gastrectomy for gastric band failures – A prospective study

BACKGROUND We prospectively evaluated the feasibility and efficacy of a strategy of performing concomitant laparoscopic band removal and sleeve gastrectomy on all-comers who had a failed laparoscopic adjustable gastric band (LABG) and analysed the impact of the reason for revision surgery on outcomes. METHODS Over a two-year period, 23 patients who previously had LAGB insertion were referred for revision surgery. Of this cohort, three patients elected to undergo band removal alone. Of the remaining 20 patients, 10 presented with weight regain and 10 presented with pathological symptoms secondary to band migration (band complication group). All patients were listed for simultaneous LABG removal and sleeve gastrectomy and the outcomes of the two groups analysed. RESULTS Simultaneous band removal and sleeve gastrectomy was achieved in all cases of weight regain and in 7 cases of band complications. There were no complications in the weight regain group and three major morbidities in the band complication group. At the time of revision, the mean body mass index was 40.3 ± 1.5; however at a mean follow-up period of 2.2 ± 0.28 years the mean BMI of the cohort had fallen to 35.9 ± 1.4. The mean BMI was significantly lower in the band complication group (p = 0.03). CONCLUSIONS Gastric band removal and revision sleeve gastrectomy following failed LABG is feasible as a single-stage procedure with good outcomes. The optimum peri-operative results of this approach are seen in patients with weight regain whilst the longer term outcomes are superior in those with band complications.

Objective assessment of the core laparoscopic skills course.

Objective. The demand for laparoscopic surgery has led to the core laparoscopic skills course (CLSC) becoming mandatory for trainees in UK. Virtual reality simulation (VR) has a great potential as a training and assessment tool of laparoscopic skills. The aim of this study was to determine the role of the CLSC in developing laparoscopic skills using the VR. Design. Prospective study. Doctors were given teaching to explain how to perform PEG transfer and clipping skills using the VR. They carried out these skills before and after the course. During the course they were trained using the Box Trainer (BT). Certain parameters assessed. Setting. Between 2008 and 2010, doctors attending the CLSC at St Georges Hospital. Participants. All doctors with minimal laparoscopic experience attending the CLSC. Results. Forty eight doctors were included. The time taken for the PEG skill improved by 52%, total left hand and right hand length by 41% and 48%. The total time in the clipping skill improved by 57%. Improvement in clips applied in the marked area was 38% and 45% in maximum vessel stretch. Conclusions. This study demonstrated that CLSC improved some aspects of the laparoscopic surgical skills. It addresses Practice-based Learning and patient care.

Resident phenotypically modulated vascular smooth muscle cells in healthy human arteries

Vascular interstitial cells (VICs) are non‐contractile cells with filopodia previously described in healthy blood vessels of rodents and their function remains unknown. The objective of this study was to identify VICs in human arteries and to ascertain their role. VICs were identified in the wall of human gastro‐omental arteries using transmission electron microscopy. Isolated VICs showed ability to form new and elongate existing filopodia and actively change body shape. Most importantly sprouting VICs were also observed in cell dispersal. RT‐PCR performed on separately collected contractile vascular smooth muscle cells (VSMCs) and VICs showed that both cell types expressed the gene for smooth muscle myosin heavy chain (SM‐MHC). Immunofluorescent labelling showed that both VSMCs and VICs had similar fluorescence for SM‐MHC and αSM‐actin, VICs, however, had significantly lower fluorescence for smoothelin, myosin light chain kinase, h‐calponin and SM22α. It was also found that VICs do not have cytoskeleton as rigid as in contractile VSMCs. VICs express number of VSMC‐specific proteins and display features of phenotypically modulated VSMCs with increased migratory abilities. VICs, therefore represent resident phenotypically modulated VSMCs that are present in human arteries under normal physiological conditions.

Minimally invasive versus open oesophagectomy for patients with oesophageal cancer: a multicentre, open-label, randomised controlled trial

Although, minimally invasive oesophagectomy was first described in the early 1990s, there is a paucity of high quality data on the relative merits of minimally-invasive versus open oesophagectomy (1,2). This is contrast to colorectal surgery where a number of randomised control trials have conclusively demonstrated the efficacy of laparoscopic colorectal resections (3). The reason for this disparity in evidence base lies in the relative rarity of oesophageal cancers combined with the variety of potential surgical approaches for resection oesophageal cancers (e.g., transhiatal, 2 stage, 3 stage and hybrid laparoscopic approaches). The paper by Beire et al. (4) is therefore very significant addition to the literature on the topic of minimally invasive oesophagectomies.

The effects of sleeve gastectomy on gastro-esophageal reflux and gastro-esophageal motility

Sleeve gastrectomy is an increasingly performed bariatric procedure associated with low morbidity and good short to medium term effects on weight loss and comorbid conditions. Studies assessing the prevalence of post-operative gastro-esophageal reflux disease (GERD), show sleeve gastrectomy may provoke de novo GERD symptoms or worsening of pre-existing GERD. Pathophysiological mechanisms of GERD after sleeve gastrectomy include a hypotensive lower esophageal sphincter, increased gastro-esophageal pressure gradient and intra-thoracic migration of the remnant stomach. A reduction in the compliance of the gastric remnant may provoke an increase in transient lower esophageal sphincter relaxations. Time-resolved MRI suggests relative gastric stasis in the proximal remnant and increased emptying from the antrum. A lack of standardisation of technique, along with heterogeneity of studies assessing GERD may explain the wide variability in reported results. Simultaneous and careful repair of an associated hiatus hernia may result in a reduction in the prevalence of post-operative GERD.

Ectopic pancreas, intussusception, and a ruptured mesenteric band: An unusual association

Although ectopic pancreas and intussusception are not unusual conditions, intussusception caused by ectopic pancreas is extremely rare. Its presence along with a ruptured congenital mesenteric vascular band raises the possibility of an anomaly of the vitelline vascular system. We report the case of a 26‐year‐old man presenting with acute abdominal pain, vomiting, and diarrhea. CT scan showed a large amount of free fluid in his abdomen and an ileo‐ileal intussusception. At laparotomy he was found to have hemoperitoneum with a ruptured, actively bleeding congenital band attached to the ileal mesentery, which was ligated, with ileo‐ileal intussusception that was resected. Histopathology showed ectopic pancreatic tissue as the lead point for the intussusception. It was likely to be a ruptured mesodiverticular band and along with other findings suggested a constellation of anomalies of the vitello‐intestinal tract. Clin. Anat. 24:128–132, 2011.

Does closure of the mesenteric defects during antecolic laparoscopic gastric bypass for morbid obesity reduce the incidence of symptomatic internal herniation

A best evidence topic in surgery was written according to a structured protocol. The question asked was whether the closure of the mesenteric defects during laparoscopic gastric bypass via antecolic approach for morbid obesity reduces the incidence of symptomatic internal herniation. 251 papers were found using the reported search strategy of which three papers best represented the answer to the question. All three studies showed that by closuring the mesenteric defects, resulted in a reduction in the incidence of symptomatic internal hernias. One study showed there to be new complications arising from primary closure, but this was undetermined statistically. The evidence still however remains limited regarding the need for closure of mesenteric defects in gastric bypass operations. We recommend there is a need for large scale randomized control trials with suitable follow up for patients.

Mesenteric paraganglioma with gallbladder paraganglion nest

We report on an original case of a 64 year old lady diagnosed with an extraadrenal mesenteric paraganglioma associated with an incidental histological finding of a gallbladder paraganglion. Paragangliomas are rare neuroendocrine, neural crest-derived tumours, found in diverse locations and display variable catecholamine secreting behaviour. Malignant potential can be difficult to predict on histology. We review the current literature on these multifarious tumours.