Calculations of the effect of catalyst size and structure on the electrocatalytic reduction of CO2 on Cu nanoclusters.

The structure and catalytic properties of Cu nanoclusters of sizes between 55 and 147 atoms were examined to understand if small Cu clusters could provide enhancement over traditional catalysts for the electrocatalysis of CO2 to CO and carbon-based fuels, such as CH4 and CH3OH, compared to bulk Cu surfaces and large Cu nanoparticles. Clusters studied included Cu55, Cu78, Cu101, Cu124, and Cu147, the structures of which were determined using global optimisation. The majority of Cu clusters examined were icosahedral, including the perfect closed-shell, partial-shell, elongated and distorted icosahedral clusters. Free energy diagrams for the reduction of CO2 showed the potential required for the formation of CO is notably smaller for all cluster sizes considered, relative to Cu(111). Less variation is observed for the limiting potential for the formation of CH4 and CH3OH. However, it was found that clusters that are either a distorted motif or contain vacancy defects yielded the best activity and provide an interesting synthesis target for future experiments.

The Birmingham Standardized Idiopathic Intracranial Hypertension Shunt Protocol: Technical Note.

BACKGROUND: Insertion of cerebrospinal fluid (CSF) shunts in patients with idiopathic intracranial hypertension (IIH) is challenging mainly due to the small ventricles and phenotypical body habitus. In this report the authors present their surgical protocol for insertion of a ventriculoperitoneal shunt (VPS) in patients with IIH and the associated revision rates. METHODS: The protocol comprises the following: shunt surgery by neurosurgeons with expertise in CSF disorders; a frontal VPS usually right sided but left sided if the left ventricle is bigger; use of the proGAV 2.0 valve with gravitational unit, set at 10 and the M.scio telemetric sensor; cannulation of the ventricle with StealthStation EM navigation system; and laparoscopic insertion of the peritoneal catheter. The authors describe the protocol and rationale and evidence behind each component and present the results of a prospective analysis on revision rates. RESULTS: The protocol has been implemented since 1 July, 2019, and by 28 February, 2022, sixty-two patients with IIH had undergone primary VPS insertion. The 30-day revision rate was 6.5%, and overall 11.3% of patients underwent revision during the study period, which compares favorably with the literature. The etiology for early failures was related to the surgical technique. CONCLUSIONS: The components of the Birmingham standardized IIH shunt protocol are evidence based and address the technical challenges of CSF diversion in patients with IIH. This protocol is associated with a low revision rate, and the authors recommend standardization for CSF shunting in IIH.

Validation of the NUn score as a predictor of anastomotic leak and major complications after Esophagectomy.

Predicting major anastomotic leak (AL) and major complications (Clavien-Dindo 3-5) following esophagectomy improves postoperative management of patients. The role of the NUn score in their prediction is controversial. This study aims to evaluate the predictive ability of this simple score. Data were retrospectively collected for consecutive esophagectomies over a 10-year period, and NUn scores were retrospectively calculated for each patient from informatics data. A standardized definition of major AL was used, excluding minor asymptomatic, radiologically detected leaks. The predictive accuracy of the NUn score and its constituent parts, for major AL and major complications, was assessed using area under receiver operating characteristics curves (AUROCs). Of 382 patients, 48 (13%) developed major AL and 123 (32%) developed major complications. The NUn score calculated on postoperative day 4 was significantly predictive of both outcomes, with AUROCs of 0.77 and 0.71, respectively (both P < 0.001). A NUn score cut-off of 10 had a negative predictive value of 95% for major AL. The NUn score was predictive of major complications on multivariable analysis. The NUn score was found to be a significant predictor of major AL, suggesting that this is a useful early warning score for major AL. The score may also be useful in identifying patients that are the most likely to benefit from enhanced recovery protocols.

Vascular calcification does not predict anastomotic leak or conduit necrosis following oesophagectomy.

BACKGROUND: Anastomotic leaks (AL) and gastric conduit necrosis (CN) are serious complications following oesophagectomy. Some studies have suggested that vascular calcification may be associated with an increased AL rate, but this has not been validated in a United Kingdom population. AIM: To investigate whether vascular calcification identified on the pre-operative computed tomography (CT) scan is predictive of AL or CN. METHODS: Routine pre-operative CT scans of 414 patients who underwent oesophagectomy for malignancy with oesophagogastric anastomosis at the Queen Elizabeth Hospital Birmingham between 2006 and 2018 were retrospectively analysed. Calcification of the proximal aorta, distal aorta, coeliac trunk and branches of the coeliac trunk was scored by two reviewers. The relationship between these calcification scores and occurrence of AL and CN was then analysed. The Esophagectomy Complications Consensus Group definition of AL and CN was used. RESULTS: Complication data were available in n = 411 patients, of whom 16.7% developed either AL (15.8%) or CN (3.4%). Rates of AL were significantly higher in female patients, at 23.0%, compared to 13.9% in males (P = 0.047). CN was significantly more common in females, (8.0% vs 2.2%, P = 0.014), patients with diabetes (10.6% vs 2.5%, P = 0.014), a history of smoking (10.3% vs 2.3%, P = 0.008), and a higher American Society of Anaesthesiologists grade (P = 0.024). Out of the 14 conduit necroses, only 4 occurred without a concomitant AL. No statistically significant association was found between calcification of any of the vessels studied and either of these outcomes. Multivariable analyses were then performed to identify whether a combination of the calcification scores could be identified that would be significantly predictive of any of the outcomes. However, the stepwise approach did not select any factors for inclusion in the final models. The analysis was repeated for composite outcomes of those patients with either AL or CN (n = 69, 16.7%) and for those with both AL and CN (n = 10, 2.4%) and again, no significant associations were detected. In the subset of patients that developed these outcomes, no significant associations were detected between calcification and the severity of the complication. CONCLUSION: Calcification scoring was not significantly associated with Anastomotic Leak or CN in our study, therefore should not be used to identify patients who are high risk for these complications.

Impact of regular enteral feeding via jejunostomy during neo-adjuvant chemotherapy on body composition in patients with oesophageal cancer.

BACKGROUND: Malnourishment and sarcopenia are well documented phenomena in oesophageal cancer. Patients undergoing neo-adjuvant chemotherapy prior to oesophagectomy have complex nutritional needs. AIM: To examine the effect of regular nutritional support via feeding jejunostomy on overall body composition in patients undergoing neo-adjuvant chemotherapy prior to oesophagectomy for oesophageal cancer. METHODS: Retrospective data were collected for 15 patients before and after neo-adjuvant chemotherapy. All patients had feeding jejunostomies inserted at staging laparoscopy prior to neo-adjuvant chemotherapy and underwent regular jejunostomy feeding. Changes in body composition were determined by analysis of computed tomography imaging. RESULTS: Patient age was 61.3 ± 12.8 years, and 73% of patients were male. The time between start of chemotherapy and surgery was 107 ± 21.6 d. There was no change in weight (74.5 ± 14.1 kg to 74.8 ± 13.1 kg) and body mass index (26.0 ± 3.8 kg/m2 to 26.1 ± 3.4 kg/m2). Body composition analysis revealed a statistically significant decrease in lumbar skeletal muscle index despite regular feeding (45.8 ± 8.0 cm2/m2 to 43.5 ± 7.3 cm2/m2; P = 0.045). The proportion of sarcopenic patients increased (33.3% to 60%). Six patients (40%) experienced dose-limiting toxicity during chemotherapy. CONCLUSION: Regular jejunostomy feeding during neo-adjuvant chemotherapy can maintain weight and adipose tissue. Feeding alone is not sufficient to maintain muscle mass. Further insight into the underlying processes causing reduced muscle mass in cancer patients may help to provide targeted interventions.

Computer-based hazard perception test scores are associated with the frequency of heavy braking in everyday driving.

Computer-based hazard perception tests are used in a number of countries as part of the driver licensing processes, and hence evaluating the validity of such tests is crucial. One strategy for assessing the validity of the scores generated by a hazard perception test is to determine whether they can predict on-road driving performance. Only a few prior studies have attempted this, all relying on the subjective ratings of an examiner who was present during a single brief drive and was not blind to the driver's demographic characteristics, potentially contaminating the outcomes. Additionally, only one such study focused on the most relevant participant group with respect to the validity of tests used in licencing processes, namely young drivers. We sought to remedy this situation in the present project by measuring young drivers' performance over an extended period of everyday driving via g-force triggered video cameras ("dashcams") installed in their own vehicles. As a precursor to the dashcam study itself, we developed a new computerized hazard perception test and assessed the validity of its scores by more traditional means (Study 1). As expected, test scores distinguished between high-risk and lower-risk driver groups, and correlated with scores on an established hazard perception test previously shown to predict crash risk. In the subsequent dashcam study (Study 2), the frequency of heavy-braking events (controlling for distance driven) was used as a more objective measure of driving performance. Results indicated that drivers with higher rates of heavy braking had slower hazard perception response times, further supporting the use of these scores as a valid measure of drivers' ability to exercise hazard perception skill during real driving. More generally, this study also demonstrates the viability of using low-cost off-the-shelf dashcams to measure real-world driving behaviour.

The value of inflammation based prognostic scores in patients undergoing surgical resection for oesophageal and gastric carcinoma.

BACKGROUND AND OBJECTIVES: Surgical interventions for oesophagogastric cancer carry a significant burden of morbidity and mortality. A range of inflammation based prognostic scores have been proposed in an attempt to predict outcome. This study evaluated five such prognostic scores in oesophageal and gastric carcinoma patients. METHODS: The modified Glasgow Prognostic Score (mGPS), Neutrophil Lymphocyte Ratio (NLR), Platelet Lymphocyte Ratio (PLR), Prognostic Index (PI), and Prognostic Nutrition Index (PNI) were calculated for 723 consecutive patients undergoing oesophagectomy or gastrectomy at a single center. The predictive accuracy of each score was assessed using ROC curves and survival analyses. RESULTS: Overall, only PLR and PNI were significantly predictive of patient survival (both P < 0.001), with no significant association detected for mGPS (P = 0.480), NLR (P = 0.210), or PI (P = 0.808). Subgroup analysis found the predictive accuracy of PNI to be significantly greater in oesophagectomy than gastrectomy patients (hazard ratio 2.75 vs 1.39, P = 0.016) and mGPS to be predictive of patient survival only in oesophagectomies (P < 0.001). CONCLUSIONS: Inflammation based prognostic scores may have a role in patients undergoing resection for oesophageal and gastric cancer. These scores are easily calculable from routinely collected data and could be used as an adjunct to existing staging modalities.

Prognostic significance of circumferential resection margin involvement in patients receiving potentially curative treatment for oesophageal cancer.

INTRODUCTION: The utility of Circumferential Resection Margin (CRM) status in predicting prognosis in oesophageal cancer is controversial, with different definitions used by the College of American Pathologists and the Royal College of Pathologists. We aimed to determine prognostic significance of CRM involvement and evaluate which system is the best predictor of prognosis. METHODS: A cohort of 390 patients who had potentially curative oesophagectomy (- + neoadjuvant chemotherapy) were analysed. Associations between CRM involvement and patient outcome were assessed for the whole cohort, and for pre-specified subgroups of T3 tumours and those who received neo-adjuvant chemotherapy. RESULTS: CRM-involvement was associated with higher T and N stage, tumour differentiation, increased tumour length and both lymphovascular and perineural invasion. Overall Survival (OS) and Recurrence Free Survival (RFS) significantly worsened with CRM-involvement (p = 0.001, p < 0.001). R1a (<1 mm but no macroscopic involvement) resulted in significantly improved OS (p = 0.037) and RFS (P = 0.026) compared to R1b (macroscopic involvement), but did not differ significantly from R0 (≥1 mm). The association between CRM-involvement and both OS and RFS remained significant regardless of whether neoadjuvant chemotherapy was given. However, CRM-involvement was not a significant prognostic marker in T3 patients (p = 0.148). Multivariable analysis found N stage, lymphovascular invasion, patient age and neoadjuvant chemotherapy to be significantly predictive of patient outcome. CRM-involvement was not a significant independent prognostic marker. CONCLUSIONS: CRM-involvement was not found to be independently predictive of prognosis, after accounting for other prognostic markers. As such, CRM should not be considered a major prognostic factor in patients with oesophageal cancer.

Prognostic significance of tumor length in patients receiving esophagectomy for esophageal cancer.

AIMS: We investigated the prognostic value of tumor length measurements acquired both from pre-operative imaging and post-operative pathology in esophageal cancer. METHODS: Tumor lengths were examined retrospectively for 389 esophagectomy patients with respect to Endoscopy, EUS (Endoscopic Ultrasound), CT and PET-CT, and pathology. Correlations between the measurements on the different approaches were assessed, and associations between tumor length and survival were analyzed. RESULTS: Only the tumor lengths assessed on pathology were found to be significantly associated with overall (P = 0.001) and recurrence free (P < 0.001) survival on univariable analysis. The median overall survival was 47.1 months in those patients with tumor lengths <3.0 cm, falling to 19.6 and 18.0 months in those with 3.0-4.4 and 4.5+ cm tumors, respectively, demonstrating a reduction in patient survival at a tumor length of around 3 cm. Tumor length on pathology was significantly correlated with tumor differentiation and both T- and N-categories. After accounting for these factors, tumor length on pathology was a significant independent predictor of recurrence-free (P = 0.016), but not overall (P = 0.128) survival. CONCLUSIONS: Tumor lengths on pathology were found to be the most predictive of patient outcome. However, after accounting for other tumor-related factors, tumor length only resulted in a marginal improvement in predictive accuracy.

Large Bowel Obstruction, a Delayed Complication of Severe Gallstone Pancreatitis.

Colonic complications are rare after acute pancreatitis but are associated with a high mortality. Possible complications include mechanical obstruction, ischaemic necrosis, haemorrhage, and fistula. We report a case of large bowel obstruction in a 31-year-old postpartum female, secondary to severe gallstone pancreatitis. The patient required emergency laparotomy and segmental bowel resection, as well as cholecystectomy. Presentation of obstruction occurs during the acute episode or can be delayed for several weeks. The most common site is the splenic flexure owing to its proximity to the pancreas. Initial management may be conservative, stenting, or surgical. CT is an acceptable baseline investigation in all cases of new onset bowel obstruction. Although bowel obstruction is a rare complication of pancreatitis, clinicians should be aware of it due to its high mortality. Obstruction can occur after a significant delay following the resolution of pancreatitis. Those patients with evidence of colonic involvement on pancreatic imaging warrant further large bowel evaluation. Bowel resection may be required electively or acutely. Colonic stenting has an increasing role in the management of large bowel obstruction but is a modality of treatment that needs further evaluation in this setting.

Diaphragmatic herniation following esophagogastric resectional surgery: an increasing problem with minimally invasive techniques? : Post-operative diaphragmatic hernias.

BACKGROUND: Post-operative diaphragmatic hernias (PODHs) are serious complications following esophagectomy or total gastrectomy. The aim of this study was to describe and compare the incidence of PODHs at a high volume center over time and analyze the outcomes of patients who develop a PODH. METHODS: A prospective database of all resectional esophagogastric operations performed for cancer between January 2001 and December 2015 was analyzed. Patients diagnosed with PODH were identified and data extracted regarding demographics, details of initial resection, pathology, PODH symptoms, diagnosis and treatment. RESULTS: Out of 631 patients who had hiatal dissection for malignancy, 35 patients developed of PODH (5.5 % overall incidence). Median age was 66 (range 23-87) years. The incidence of PODH in each operation type was: 2 % (4/221) following an open 2 or 3 stage esophagectomy, 10 % (22/212) following laparoscopic hybrid esophagectomy, 7 % (5/73) following MIO, and 3 % (4/125) following total gastrectomy. The majority of patients had colon or small bowel in a left-sided hernia. Of the 35 patients who developed a PODH, 20 (57 %) patients required emergency surgery, whereas 15 (43 %) had non-urgent repair. The majority of the patients had had suture repair (n = 24) or mesh repair (n = 7) of the diaphragmatic defect. Four patients were treated non-operatively. In hospital post-operative mortality was 20 % (4/20) in the emergency group and 0 % (0/15) in the elective group. Further hernia recurrence affected seven patients (n = 7/27, 26 %) and 4 of these patients (15 %) presented with multiple recurrences. CONCLUSION: PODH is a common complication following hybrid esophagectomy and MIO. Given the high mortality from emergency repair, careful thought is needed to identify surgical techniques to prevent PODH forming when minimal access esophagectomy are performed. Upper GI surgeons need to have a low index of suspicion to investigate and treat patients for this complication.

Follow-up of gastric cancer: a review.

Although there is broad agreement in the staging, classification, and surgery for gastric cancer, there is no consensus regarding follow-up after gastrectomy. Follow-up varies from investigations on clinical suspicion of relapse to intensive investigations to detect recurrences early, assuming that this improves survival and quality of life. Advanced gastric cancers recur mainly by locoregional recurrence or distant metastasis. Local recurrences detected at endoscopy or on computed tomography (CT) are invariably incurable. For early gastric cancers, endoscopy can detect new primaries, but the incidence of these tumors is low, and many thousands of procedures are required to detect each operable case. CT is much better at detecting liver metastasis and, although these are usually multiple and unresectable, there are several reports of good survival following liver resection for isolated metastasis. Tumor markers have been used with some success to detect subclinical recurrences and could be used to target more invasive or expensive procedures. In chemotherapy, many newer agents are promising significantly improved survival, but again, the evidence for greater benefit when administered prior to the patient becoming symptomatic is lacking. Overall, it appears that follow-up policy is as much decided by the wealth and facilities of the institution as by any significant evidence base. Although the early detection of recurrent cancer is an emotive issue for both patients and surgeons, considering the amount of time and money invested in follow-up, and the lack of evidence of efficacy, a randomized controlled trial of intensive follow-up is required.

Results of percutaneous subintimal angioplasty using routine stenting.

OBJECTIVE: To assess the long-term patency and clinical success of subintimal angioplasty in patients with limb-threatening ischemia. METHODS: From 1999 through 2004, 29 patients with superficial femoral artery (SFA) or popliteal artery occlusion and rest pain or tissue loss underwent subintimal angioplasty. Patients had subintimal wire placement followed by percutaneous transluminal angioplasty and stent placement. From 1 to 10 stents were placed. Technical success required stenosis less than 30% by arteriography, a velocity ratio less than 1.5 by duplex scan, and improvement of the ankle-brachial index greater than 0.15. Follow-up duplex scanning was performed every 3 months for 2 years and then every 6 months thereafter. RESULTS: Initial success was obtained in 26 (90%) of the 29 patients, with an improvement in the mean ankle-brachial index of 0.25. Mean follow-up was 38 months (range, 28-54 months). During follow-up, 16 arteries reoccluded. Six of the 16 patients had recurrent symptoms, four required below-knee amputation, two required above-knee amputation, and four died with an intact limb. After treatment failure, two patients had attempted tissue plasminogen activator (TPA), and four had prosthetic tibial bypass. Overall, 15 patients died, and only 2 of the 14 who lived had a patent artery. One of the two required percutaneous transluminal angioplasty of the recanalized artery. By life-table analysis, success was 85%, 64%, 18%, and 9% at 1, 2, 3, and 4 years, respectively. Periprocedural complications occurred in four patients. Of the 13 patients with wounds, six died (four healed), two were alive with healed wounds, and five had limb loss. Of 16 patients with rest pain, 14 developed recurrent symptoms after reocclusion, 1 was alive without pain, and 1 underwent amputation. CONCLUSIONS: Subintimal angioplasty is technically successful in most patients, with few complications. Most procedures provide short-term clinical success and have allowed for successful wound healing and temporary relief of rest pain. However, late arterial patency is poor, with a high rate of symptom recurrence. Many patients will have recurrent pain, and some will require major amputation. Nevertheless, limb-salvage rates are significantly better than arterial patency. Intermediate-term patency is higher than that commonly reported for prosthetic bypass, and despite the lack of durable long-term patency, the procedure offers an additional potentially effective therapeutic option in the treatment of patients with limb-threatening ischemia and femoropopliteal occlusion.

Treatment of limb-threatening ischemia with percutaneous intentional extraluminal recanalization: a preliminary evaluation.

OBJECTIVE: We assessed the technical success, safety, and short-term effectiveness of percutaneous intentional extraluminal recanalization (PIER) in patients with limb-threatening ischemia and no autologous vein or with a major contraindication to surgery. METHODS: From 1999 through 2002, 25 patients with femoropopliteal occlusion and rest pain or tissue loss underwent PIER. Thirteen patients had undergone one or more failed bypass surgeries in the treated lower extremity, and no patient had suitable vein for bypass grafting. In four patients the ejection fraction was less than 15%; four patients had severe nonreconstructable coronary artery disease; and two patients with metastatic cancer refused amputation. All patients underwent subintimal wire placement, followed by percutaneous transluminal angioplasty and intracoil stent placement. Occlusions ranged in length from 6 to 18 cm, and 1 to 10 stents were placed. Technical success required no residual stenosis greater than 30% on arteriography, velocity ratio less than 1.5 on duplex ultrasound scanning, and improvement in ankle-brachial index of 0.15 or greater. Follow-up duplex scanning was performed every 3 months. RESULTS: Initial success was obtained in 23 of 25 patients (92%), with ankle-brachial index improvement of.31 to.54. All successful procedures resulted in symptomatic improvement. Mean follow-up was 13.3 months (range, 4-30 months). During follow-up, 10 patients died and 2 arteries demonstrated recurrent occlusion. With life table analysis, success rate was 92% at 12 months. Of the 4 patients in whom the procedure failed, 3 required major amputation and symptoms persisted in one. Complications occurred after two procedures, one myocardial infarction and one groin hematoma. CONCLUSIONS: PIER is technically possible in patients with femoropopliteal occlusion, and the procedure is associated with a low complication rate. Most procedures provide at least short-term clinical success and have enabled successful wound healing and pain relief in patients without other effective options. Further studies and longer follow-up are required to determine long-term success and the role of PIER in treatment of femoropopliteal occlusion.