| 1. |
- Abu Hilal, M, et al.
(författare)
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Laparoscopic radical 'no-touch' left pancreatosplenectomy for pancreatic ductal adenocarcinoma : technique and results.
- 2016
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Ingår i: Surgical Endoscopy. - : Springer Science and Business Media LLC. - 0930-2794 .- 1432-2218. ; 30:9, s. 3830-8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Laparoscopic left pancreatectomy has been well described for benign pancreatic lesions, but its role in pancreatic adenocarcinoma remains open to debate. We report our results adopting a laparoscopic technique that obeys established oncologic principles of open distal pancreatosplenectomy.METHODS: This is a post hoc analysis of a prospectively kept database of 135 consecutive patients undergoing laparoscopic left pancreatectomy, performed across two sites in the UK and the Netherlands (07/2007-07/2015 Southampton and 10/2013-07/2015 Amsterdam). Primary outcomes were resection margin and lymph node retrieval. Secondary endpoints were other perioperative outcomes, including post-operative pancreatic fistula. Definition of radical resection was distance tumour to resection margin >1 mm. All patients underwent 'laparoscopic radical left pancreatosplenectomy' (LRLP) which involves 'hanging' the pancreas including Gerota's fascia, followed by clockwise dissection, including formal lymphadenectomy.RESULTS: LRLP for pancreatic adenocarcinoma was performed in 25 patients. Seven of the 25 patients (28 %) had extended resections, including the adrenal gland (n = 3), duodenojejunal flexure (n = 2) or transverse mesocolon (n = 3). Mean age was 68 years (54-81). Conversion rate was 0 %, mean operative time 240 min and mean blood loss 340 ml. Median intensive/high care and hospital stay were 1 and 5 days, respectively. Clavien-Dindo score 3+ complication rate was 12 % and ISGPF grade B/C pancreatic fistula rate 28 %; 90-day (or in-hospital) mortality was 0 %. The pancreatic resection margin was clear in all patients, and the posterior margin was involved (<1 mm) in 6 patients, meaning an overall R0 resection rate of 76 %. No resection margin was microscopically involved. Median nodal sample was 15 nodes (3-26). With an average follow-up of 17.2 months, 1-year survival was 88 %.CONCLUSIONS: A standardised laparoscopic approach to pancreatic adenocarcinoma in the left pancreas can be adopted safely. Our study shows that these results can be reproduced across multiple sites using the same technique.
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| 2. |
- Backman, Olof, et al.
(författare)
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Laparoscopic Roux-en-Y Gastric Bypass Without Division of the Mesentery Reduces the Risk of Postoperative Complications
- 2019
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Ingår i: Surgical Endoscopy. - : Springer. - 0930-2794 .- 1432-2218. ; 33:9, s. 2858-2863
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Tidskriftsartikel (refereegranskat)abstract
- Background: Anastomotic complications after laparoscopic Roux-en-Y gastric bypass (LRYGB) including leaks, ulceration, and stenosis remain a significant cause of post-operative morbidity and mortality. Our objective was to compare two different surgical techniques regarding short-term anastomotic complications.Methods: A retrospective analysis of all patients operated with a primary LRYGB from 2006 to June 2015 in one institution, where prospectively collected data from an internal quality registry and medical journals were analyzed.Results: In total, 2420 patients were included in the analysis. 1016 were operated with a technique where the mesentery was divided during the creation of the Roux-limb (DM-LRYGB) and 1404 were operated with a method where the mesentery was left intact (IM-LRYGB). Leakage in the first 30 days [2.6% vs. 1.1% (p < 0.05)], and ulceration or stenosis occurring during the first 6 months after surgery [5.6% vs. 0.1% (p < 0.05)] was significantly higher in the DM-LRYGB group. Adjusted odds ratio for anastomotic leak was 0.46 (95% CI 0.24-0.87) and for stenosis/ulceration 0.01 (95% CI 0.002-0.09).Conclusion: IM-LRYGB seems to reduce the risk of complications at the anastomosis. A plausible explanation for this is that the blood supply to the anastomosis is compromised when the mesentery is divided.
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| 5. |
- Deijen, Charlotte L., et al.
(författare)
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Ten-year outcomes of a randomised trial of laparoscopic versus open surgery for colon cancer
- 2017
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Ingår i: Surgical Endoscopy. - : SPRINGER. - 0930-2794 .- 1432-2218. ; 31:6, s. 2607-2615
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Tidskriftsartikel (refereegranskat)abstract
- Laparoscopic surgery for colon cancer is associated with improved recovery and similar cancer outcomes at 3 and 5 years in comparison with open surgery. However, long-term survival rates have rarely been reported. Here, we present survival and recurrence rates of the Dutch patients included in the COlon cancer Laparoscopic or Open Resection (COLOR) trial at 10-year follow-up. Between March 1997 and March 2003, patients with non-metastatic colon cancer were recruited by 29 hospitals in eight countries and randomised to either laparoscopic or open surgery. Main inclusion criterion for the COLOR trial was solitary adenocarcinoma of the left or right colon. The primary outcome was disease-free survival at 3 years, and secondary outcomes included overall survival and recurrence. The 10-year follow-up data of all Dutch patients were collected. Analysis was by intention-to-treat. The trial was registered at ClinicalTrials.gov (NCT00387842). In total, 1248 patients were randomised, of which 329 were Dutch. Fifty-eight Dutch patients were excluded and 15 were lost to follow-up, leaving 256 patients for 10-year analysis. Median follow-up was 112 months. Disease-free survival rates were 45.2 % in the laparoscopic group and 43.2 % in the open group (difference 2.0 %; 95 % confidence interval (CI) -10.3 to 14.3; p = 0.96). Overall survival rates were 48.4 and 46.7 %, respectively (difference 1.7 %; 95 % CI -10.6 to 14.0; p = 0.83). Stage-specific analysis revealed similar survival rates for both groups. Sixty-two patients were diagnosed with recurrent disease, accounting for 29.4 % in the laparoscopic group and 28.2 % in the open group (difference 1.2 %; 95 % CI -11.1 to 13.5; p = 0.73). Seven patients had port- or wound-site recurrences (laparoscopic n = 3 vs. open n = 4). Laparoscopic surgery for non-metastatic colon cancer is associated with similar rates of disease-free survival, overall survival and recurrences as open surgery at 10-year follow-up.
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| 7. |
- Edholm, David, et al.
(författare)
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Importance of pouch size in laparoscopic Roux-en-Y gastric bypass : a cohort study of 14,168 patients
- 2016
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Ingår i: Surgical Endoscopy. - : Springer Science and Business Media LLC. - 0930-2794 .- 1432-2218. ; 30:5, s. 2011-2015
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Laparoscopic Roux-en-Y gastric bypass (LRYGB) is one of the most common bariatric procedures worldwide, but the importance of gastric pouch size is still under debate. We have studied how pouch size affects risk of marginal ulcer and excess body mass index loss (EBMIL%) at 6 weeks and 1 year postoperatively.METHODS: Scandinavian Obesity Surgery Registry included 14,168 LRYGB patients with linear stapled gastrojejunostomies, having complete pre- and postoperative data concerning length of stapler needed to complete the gastric pouch, incidence of marginal ulcers and weight loss. LRYGB technique in Sweden is highly standardized, and total length of stapler was used as a proxy for pouch size.RESULTS: Mean length of stapler used for the pouch was 145 mm. At 1 year, symptomatic marginal ulcers were noted in 0.9 % of the patients. The relative risk of marginal ulcer increased by 14 % (95 % confidence interval 9-20 %), for each centimeter of stapler used for the pouch. Body mass index (BMI) was reduced from 42.4 ± 5.1 to 36.1 kg/m(2) at 6 weeks and 28.9 kg/m(2) at 1 year. The total length of stapler predicted EBMIL% at 6 weeks but not at 1 year. Female gender, low preoperative BMI, young age and absence of diabetes predicted better EBMIL% at 1 year.CONCLUSION: A smaller pouch reduces the risk of marginal ulcers, but does not predict better weight loss at 1 year. Additional stapling should be avoided as each extra centimeter increases the relative risk of marginal ulcers by 14 %.
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| 8. |
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| 9. |
- Grong, Eivind, et al.
(författare)
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Sleeve gastrectomy, but not duodenojejunostomy, preserves total beta-cell mass in Goto-Kakizaki rats evaluated by three-dimensional optical projection tomography
- 2016
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Ingår i: Surgical Endoscopy. - : Springer Science and Business Media LLC. - 0930-2794 .- 1432-2218. ; 30:2, s. 532-542
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Tidskriftsartikel (refereegranskat)abstract
- Background In type 2 diabetes mellitus, there is a progressive loss of beta-cell mass. Bariatric surgery has in recent investigations showed promising results in terms of diabetes remission, but little is established regarding the effect of surgery on the survival or regeneration of pancreatic beta-cells. In this study, we aim to explore how bariatric surgery with its subsequent hormonal alterations affects the islets of Langerhans.Methods Twenty-four Goto-Kakizaki rats were operated with duodenojejunostomy (DJ), sleeve gastrectomy (SG) or sham operation. From the 38th week after surgery, body weight, fasting blood glucose, glycosylated hemoglobin, mixed meal tolerance with repeated measures of insulin, glucagon-like peptide 1, gastrin and total ghrelin were evaluated. Forty-six weeks after surgery, the animals were euthanized and the total beta-cell mass in all animals was examined by three-dimensional volume quantification by optical projection tomography based on the signal from insulin-specific antibody staining.Results Body weight did not differ between groups (Pg = 0.37). SG showed lower fasting blood glucose compared to DJ and sham (Pg = 0.037); HbA1c levels in SG were lower compared to DJ only (p\0.05). GLP-1 levels were elevated for DJ compared to SG and sham (Pg = 0.001), whereas gastrin levels were higher in SG compared to the two other groups (Pg = 0.002). Beta-cell mass was significantly greater in animals operated with SG compared to both DJ and sham (p = 0.036).Conclusion Sleeve gastrectomy is superior to duodenojejunostomy and sham operation when comparing the preservation of beta-cell mass 46 weeks after surgery in Goto-Kakizaki rats. This could be related to both the increased gastrin levels and the long-term improvement in glycemic parameters observed after this procedure.
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| 10. |
- Hedenström, Per, et al.
(författare)
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High clinical impact and diagnostic accuracy of EUS-guided biopsy sampling of subepithelial lesions: a prospective, comparative study.
- 2018
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Ingår i: Surgical endoscopy. - : Springer Science and Business Media LLC. - 1432-2218 .- 0930-2794. ; 32:3, s. 1304-1313
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Tidskriftsartikel (refereegranskat)abstract
- In a tertiary center setting we aimed to study the diagnostic accuracy and clinical impact of EUS-guided biopsy sampling (EUS-FNB) with a reverse bevel needle compared with that of fine needle aspiration (EUS-FNA) in the work-up of subepithelial lesions (SEL).All patients presenting with SELs referred for EUS-guided sampling were prospectively included in 2012-2015. After randomization of the first pass modality, dual sampling with both EUS-FNB and EUS-FNA was performed in each lesion. Outcome measures in an intention-to-diagnose analysis were the diagnostic accuracy, technical failures, and adverse events. The clinical impact was measured as the performance of additional diagnostic procedures post-EUS and the rate of unwarranted resections compared with a reference cohort of SELs sampled in the same institution 2006-2011.In 70 dual sampling procedures of unique lesions (size: 6-220mm) the diagnostic sensitivity for malignancy and the overall accuracy of EUS-FNB was superior to EUS-FNA compared head-to-head (90 vs 52%, and 83 vs 49%, both p<0.001). The adverse event rate of EUS-FNB was low (1.2%). EUS-FNB in 2012-2015 had a positive clinical impact in comparison with the reference cohort demonstrated by less cases referred for an additional diagnostic procedure, 12/83 (14%) vs 39/73 (53%), p<0.001, and fewer unwarranted resections in cases subjected to surgery, 3/48 (6%) vs 12/35 (34%), p=0.001.EUS-FNB with a reverse bevel needle is safe and superior to EUS-FNA in providing a conclusive diagnosis of subepithelial lesions. This biopsy sampling approach facilitates a rational clinical management and accurate treatment.
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| 14. |
- Ohya, T, et al.
(författare)
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Colorectal ESD in day surgery
- 2017
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Ingår i: Surgical endoscopy. - : Springer Science and Business Media LLC. - 1432-2218 .- 0930-2794. ; 31:9, s. 3690-3695
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Tidskriftsartikel (refereegranskat)
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| 15. |
- Oussi, Ninos, et al.
(författare)
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Video analysis in basic skills training : a way to expand the value and use of BlackBox training?
- 2018
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Ingår i: Surgical Endoscopy. - : Springer Science and Business Media LLC. - 0930-2794 .- 1432-2218. ; 32:1, s. 87-95
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundBasic skills training in laparoscopic high-fidelity simulators (LHFS) improves laparoscopic skills. However, since LHFS are expensive, their availability is limited. The aim of this study was to assess whether automated video analysis of low-cost BlackBox laparoscopic training could provide an alternative to LHFS in basic skills training.MethodsMedical students volunteered to participate during their surgical semester at the Karolinska University Hospital. After written informed consent, they performed two laparoscopic tasks (PEG-transfer and precision-cutting) on a BlackBox trainer. All tasks were videotaped and sent to MPLSC for automated video analysis, generating two parameters (Pl and Prtcl_tot) that assess the total motion activity. The students then carried out final tests on the MIST-VR simulator. This study was a European collaboration among two simulation centers, located in Sweden and Greece, within the framework of ACS-AEI.Results31 students (19 females and 12 males), mean age of 26.2 ± 0.8 years, participated in the study. However, since two of the students completed only one of the three MIST-VR tasks, they were excluded. The three MIST-VR scores showed significant positive correlations to both the Pl variable in the automated video analysis of the PEG-transfer (RSquare 0.48, P < 0.0001; 0.34, P = 0.0009; 0.45, P < 0.0001, respectively) as well as to the Prtcl_tot variable in that same exercise (RSquare 0.42, P = 0.0002; 0.29, P = 0.0024; 0.45, P < 0.0001). However, the correlations were exclusively shown in the group with less PC gaming experience as well as in the female group.ConclusionsAutomated video analysis provides accurate results in line with those of the validated MIST-VR. We believe that a more frequent use of automated video analysis could provide an extended value to cost-efficient laparoscopic BlackBox training. However, since there are gender-specific as well as PC gaming experience differences, this should be taken in account regarding the value of automated video analysis.
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| 16. |
- Persson, Jan, 1962, et al.
(författare)
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Fully covered stents are similar to semi-covered stents with regard to migration in palliative treatment of malignant strictures of the esophagus and gastric cardia : results of a randomized controlled trial.
- 2017
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Ingår i: Surgical Endoscopy. - : Springer Science and Business Media LLC. - 0930-2794 .- 1432-2218. ; 31:10, s. 4025-4033
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Stent migration is a significant clinical problem in palliation of malignant strictures in the esophagus and gastro-esophageal junction (GEJ). We have compared a newer design of a fully-covered stent to a widely used semi-covered stent using migration >20 mm as the primary outcome variable. Effects on dysphagia, quality of life (QoL) and re-intervention frequency were also investigated.METHODS: Patients with dysphagia due to non-curable esophagus/GEJ cancer were randomized to receive either a more recent design of a fully-covered stent (n = 48) or a conventional semi-covered stent (n = 47). Chest x-ray, dysphagia and QoL were studied at baseline, one week, four weeks and three months thereafter.RESULTS: There were no significant differences either in stent migration distance or in the migration frequency. Stent migration during the total study period occurred in 37.2 % in the semi-covered group compared to 20.0 % for the fully-covered group. Dysphagia was measured with Watson and Ogilvie scores and with the dysphagia module in the QoL scale (QLQ-OG25). On average, there was a tendency to better dysphagia relief for the fully-covered design as scored with the two latter dysphagia instruments (p= 0.081 and p= 0.067) at three months and towards more re-interventions in the semi-covered group (p= 0.083).CONCLUSION: In spite of its somewhat lower intrinsic radial force, the fully-covered stent was comparable to the conventional semi-covered stent with regard to stent migration. The data further suggest a potential benefit of the fully-covered stent in improving dysphagia in patients with longer life expectancy.
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| 17. |
- Sima, Eduardo, et al.
(författare)
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Gastrointestinal symptoms, weight loss and patient satisfaction 5 years after gastric bypass : a study of three techniques for the gastrojejunal anastomosis.
- 2016
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Ingår i: Surgical Endoscopy. - : Springer Science and Business Media LLC. - 0930-2794 .- 1432-2218. ; 30:4, s. 1553-1558
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The optimal operative technique in gastric bypass (RYGB) is still under debate. We have studied patient-reported gastrointestinal symptoms and weight loss 5 years after RYGB performed with three different stapling techniques for the gastrojejunal anastomosis (GJ).METHODS: Out of 593 patients operated with RYGB, 489 patients [80.2 % women, body mass index (BMI) 44.9 (33-68) kg/m(2)] answered our 5-year follow-up questionnaire concerning gastrointestinal symptoms (vomiting, reflux, dumping, abdominal pain or diarrhea), weight loss, need for postoperative endoscopic interventions and overall satisfaction with the procedure. We compared the results for three different GJ techniques: linear stapler (LS, n = 103), 21-mm circular stapler (C21, n = 88) and 25-mm circular stapler (C25, n = 298).RESULTS: Dumping was the most commonly reported symptom (14.1 % of all patients on a weekly to daily basis), however, less frequently reported in the C25 group (p < 0.05). Vomiting, prevalent in 2.9 % of all patients, was more frequently reported in the C21 group (p < 0.01). No group consistently showed greater weight loss compared to the other two groups. A higher incidence of endoscopic dilatations due to strictures was reported in the C21 group (12.5 % compared to 4.5 % of all patients, p < 0.05). Overall patient satisfaction was high (88 %).CONCLUSION: Our data suggest that the technique for the construction of the GJ in RYGB affects gastrointestinal symptoms 5 years postoperatively. The difference is moderate but indicates that a narrow GJ results in increased frequency of vomiting and need for endoscopic interventions without improving the weight result.
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| 18. |
- Soreide, Jon Arne, et al.
(författare)
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Endoscopic retrograde cholangiopancreatography (ERCP) : lessons learned from population-based national registries: a systematic review
- 2019
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Ingår i: Surgical Endoscopy. - : Springer-Verlag New York. - 0930-2794 .- 1432-2218. ; 33:6, s. 1731-1748
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Forskningsöversikt (refereegranskat)abstract
- Background: Endoscopic retrograde cholangiopancreatography (ERCP) was introduced more than four decades ago as a diagnostic tool for biliary and pancreatic diseases. Currently, ERCP is mainly used as a therapeutic approach to relieve biliary or pancreatic duct obstruction. Clinical practice has been based on a few large reports and some randomized controlled trials. These data are valuable and important, but the external validity of these reports is limited. Implementation into routine practice should be balanced with the knowledge that these studies were conducted under very specific circumstances. This review was undertaken to describe ERCP results from population-based national registries recorded during routine clinical practice.Methods: A systematic literature search of the electronic databases Medline Ovid and Embase was conducted. Eligible papers were selected and data were recorded according to the PRISMA criteria.Results: Thirty-one studies were included: 15 true national population-based and 16 population-level studies. Most studies originated from countries with a governmental public health care system. At least three-quarters of the ERCP procedures are currently therapeutic, and the technical success rate is high (>90%). The postprocedure 30-day mortality rate ranged between 1 and 5% and was strongly correlated with older age, male sex, emergency admission, and noncancer comorbidities, but exhibited a lower correlation with the annual ERCP volume. Patients with primary sclerosing cholangitis or liver cirrhosis should receive particular attention. The risk of developing a bile duct, liver, or pancreas malignancy after ERCP tended to increase, but endoscopic sphincterotomy did not affect this risk.Conclusion: ERCP is currently mainly used as a therapeutic approach, and the results are generally likely to improve patients' conditions. A nationwide registry enables better monitoring of routine clinical practice. The collection of valuable information from routine clinical practice in population-based databases may help to improve patient care from best evidence to best practice.
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| 23. |
- Wells, Antonia C., et al.
(författare)
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Operating hurts : a study of EAES surgeons
- 2019
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Ingår i: Surgical Endoscopy. - : SPRINGER. - 0930-2794 .- 1432-2218. ; 33:3, s. 933-940
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundWork-related pain and discomfort experienced by surgeons is widely reported in the literature. A survey was, therefore, conducted to explore this issue among members of the European Association for Endoscopic Surgery (EAES).MethodsThe survey was emailed to 2980 EAES members in 2017 enquiring about their working practice, musculoskeletal (MSK) pain and burnout.ResultsA total of 569 (19%) surgeons responded, of whom 556 were practicing surgeons; 86% were consultants, 84% were male, and 94% were right-handed. Respondents operated on average 3.3days/week with 27% of their procedures lasting longer than 3h. The 386 endoscopists surveyed reported performing an average of 5.3 procedures/day with 83% performing endoscopy at least once per week. Over half of practicing surgeons (62%) reported their worst pain score was 3 or higher (10-point scale) in the past 7 working days, encompassing 71% of their open, 72% laparoscopic, 48% robot-assisted cases and 52% of their endoscopies. Of the 120 surgeons who had ever sought medical help for aches, pain or discomfort, 38% were currently in pain and 16% had considered leaving surgery due to their MSK pain, 26% had reported work-related pain to their employer, 26% had been on short-term disability during their career and 4% long-term disability due to MSK disorders. A significant proportion of the respondents (49%) felt their physical discomfort would influence the ability to perform or assist with surgical procedures in the future. These surgeons reported significantly lower satisfaction from their work (p=0.024), higher burnout (p=0.005) and significantly higher callousness toward people (p<0.001) than those not fearing loss of career longevity.ConclusionThe results show that MSK pain is prevalent amongst EAES members. Nearly half the respondents had career longevity fears from pain/discomfort which, in turn, correlated with more prevalent feelings of burnout. More emphasis should be placed on the aetiology, prevention and management of musculoskeletal pain in the surgical workforce.
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| 24. |
- Yu, Denny, et al.
(författare)
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Intraoperative workload in robotic surgery assessed by wearable motion tracking sensors and questionnaires
- 2017
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Ingår i: Surgical Endoscopy. - : Springer-Verlag New York. - 0930-2794 .- 1432-2218. ; 31:2, s. 877-886
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Tidskriftsartikel (refereegranskat)abstract
- Background: The introduction of robotic technology has revolutionized radical prostatectomy surgery. However, the potential benefits of robotic techniques may have trade-offs in increased mental demand for the surgeon and the physical demand for the assisting surgeon. This study employed an innovative motion tracking tool along with validated workload questionnaire to assess the ergonomics and workload for both assisting and console surgeons intraoperatively. Methods: Fifteen RARP cases were collected in this study. Cases were performed by 10 different participants, six primarily performed console tasks and four primarily performed assisting tasks. Participants had a median 12 (min—3, max—25) years of surgical experience. Both console and assisting surgeons performed robotic prostatectomy cases while wearing inertial measurement units (IMUs) that continuously track neck, shoulder, and torso motion without interfering with the sterile environment. Postoperatively, participants completed a workload questionnaire (SURG-TLX) and a body part discomfort questionnaire. Results: Twenty-six questionnaires were completed from 13 assisting and 13 console surgeons over the 15 cases. Postoperative pain was reported highest for the right shoulder and neck. Mental demands were 41 % higher for surgeons at the console than assisting (p < 0.05), while physical demands were not significantly different. Assisting surgeons worked in demanding neck postures for 58 % of the procedure compared to 24 % for the console surgeon (p < 0.01). Surgeons at the console were primarily static and showed 2–5 times fewer movements than assisting surgeons (p < 0.01). Conclusions: Postures were more ergonomic during console tasks than when assisting by the bedside; however, the console may constrain postures leading to static loads that have been associated with musculoskeletal symptoms for the neck, torso, and shoulders. The IMU sensors were effective at quantifying ergonomics in robotic prostatectomies, and these methods and findings have broad applications to other robotic procedures.
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| 25. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Recognition and approval of potassic-richerite, an amphibole supergroup mineral, from the Pajsberg mines, Filipstad, Sweden.
- 2019
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Ingår i: Mineralogy and Petrology. - : Springer. - 0930-0708 .- 1438-1168. ; 113, s. 7-16
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Tidskriftsartikel (refereegranskat)abstract
- Potassic-richterite, ideally AKB(NaCa)CMg5TSi8O22W(OH)2, is recognized as a valid member of the amphibole supergroup (IMA CNMNC 2017–102). Type material is from the Pajsberg Mn-Fe ore field, Filipstad, Värmland, Sweden, where the mineral occurs in a Mn-rich skarn, closely associated with mainly phlogopite, jacobsite and tephroite. The megascopic colour is straw yellow to grayish brown and the luster vitreous. The nearly anhedral crystals, up to 4 mm in length, are pale yellow (non-pleochroic) in thin section andoptically biaxial (−), with α = 1.615(5), β = 1.625(5), γ = 1.635(5). The calculated density is 3.07 g·cm−1. VHN100 is in the range 610–946. Cleavage is perfect along {110}. EPMA analysis in combination with Mössbauer and infrared spectroscopy yields the empirical formula (K0.61Na0.30Pb0.02)Σ0.93(Na1.14Ca0.79Mn0.07)Σ2(Mg4.31Mn0.47Fe3+0.20)Σ5(Si7.95Al0.04Fe3+0.01)Σ8O22(OH1.82F0.18)Σ2 for a fragmentused for collection of single-crystal X-ray diffraction data. The infra-red spectra show absorption bands at 3672 cm−1 and 3736 cm−1 for the α direction. The crystal structure was refined in space group C2/m to R1=3.6% [I >2σ(I)], with resulting cellparameters a = 9.9977(3) Å, b = 18.0409(4) Å, c = 5.2794(2) Å, γ = 104.465(4)°, V = 922.05(5) Å3 and Z=2. The A and M(4) sites split into A(m) (K+), A(2/m) (Na+), A(2) (Pb2+), and M(4′) (Mn2+) subsites, respectively. The remaining Mn2+ is strongly ordered at theoctahedrally coordinated M(2) site, possibly together with most of Fe3+. The skarn bearing potassic-richterite formed at peak metamorphism, under conditions of low SiO2 and Al2O3 activities and relatively high oxygen fugacities.
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