Topological defect lasers

We demonstrate topological defect lasers in a GaAs membrane with embedded InAs quantum dots. By introducing a disclination to a square-lattice of elliptical air holes, we obtain spatially confined optical resonances with high quality factor. Such resonances support powerflow vortices, and lase upon optical excitation of quantum dots, embedded in the structure. The spatially inhomogeneous variation of the unit cell orientation adds another dimension to the control of a lasing mode, enabling the manipulation of its field pattern and energy flow landscape

The effect of age on short-term and mid-term outcomes after thoracoscopic Ivor Lewis esophagectomy: a propensity score-matched analysis

Background: The number of elderly patients diagnosed with esophageal cancer rises. Current information about outcomes in elderly patients undergoing thoracoscopic Ivor Lewis esophagectomy is limited. The objective of this study was to evaluate the influence of age on short-and mid-term outcomes after thoracoscopic Ivor Lewis esophagectomy. Methods: A retrospective review of 188 patients with esophageal cancer undergoing thoracoscopic Ivor Lewis esophagectomy between August 2014 and July 2019 was performed. Patients were divided into patients aged > 75 years (elderly group (EG), n = 37) and patients = grade III) were compared. Results: After matching 74 patients remained (n = 37 in each group). Postoperatively, no significant differences in major and overall complications, intra-hospital and 30-day mortality, disease-free or overall survival up to 3 years after surgery were noted. The incidence of pulmonary complications (65% vs. 38%) and pneumonia (54% vs. 30%) was significantly higher and the median hospital length of stay (12 vs. 14 days) significantly longer in the EG versus YG. Conclusion: Thoracoscopic Ivor Lewis esophagectomies resulted in acceptable postoperative major morbidity and mortality without compromising 3-years overall and disease-free survival in elderly compared to younger patients with esophageal cancer. However, the incidence of postoperative pulmonary complications was higher in patients aged over 75 years

Robotic-assisted pancreatic surgery in the elderly patient: experiences from a high-volume centre

Background: Robotic-assisted pancreatic surgery (RPS) has fundamentally developed over the past few years. For subgroups, e.g. elderly patients, applicability and safety of RPS still needs to be defined. Given prognosticated demographic developments, we aim to assess the role of RPS based on preoperative, operative and postoperative parameters. Methods: We included 129 patients undergoing RPS at our institution between 2017 and 2020. Eleven patients required conversion to open surgery and were excluded from further analysis. We divided patients into two groups; >= 70 years old (Group 1; n = 32) and < 70 years old (Group 2; n = 86) at time of resection. Results: Most preoperative characteristics were similar in both groups. However, number of patients with previous abdominal surgery was significantly higher in patients >= 70 years old (78% vs 37%, p = 70 years old stayed significantly longer at ICU (1.8 vs 0.9 days; p = 0.037), length of hospital stay and postoperative morbidity were equivalent between the groups. Conclusion: RPS is safe and feasible in elderly patients and shows non-inferiority when compared with younger patients. However, prospectively collected data is needed to define the role of RPS in elderly patients accurately. Trial registration Clinical Trial Register: Deutschen Register Klinischer Studien (DRKS; German Clinical Trials Register). Clinical Registration Number: DRKS00017229 (retrospectively registered, Date of Registration: 2019/07/19, Date of First Enrollment: 2017/10/18)

Thoracic Surgery in the COVID-19 Pandemic: A Novel Approach to Reach Guideline Consensus

The COVID-19 pandemic challenges international and national healthcare systems. In the field of thoracic surgery, procedures may be deferred due to mandatory constraints of the access to diagnostics, staff and follow-up facilities. There is a lack of prospective data on the management of benign and malignant thoracic conditions in the pandemic. Therefore, we derived recommendations from 14 thoracic societies to address key questions on the topic of COVID-19 in the field of thoracic surgery. Respective recommendations were extracted and the degree of consensus among different organizations was calculated. A high degree of consensus was found to temporarily suspend non-critical elective procedures or procedures for benign conditions and to prioritize patients with symptomatic or advanced cancer. Prior to hospitalization, patients should be screened for respiratory symptoms indicating possible COVID-19 infection and most societies recommended to screen all patients for COVID-19 prior to admission. There was a weak consensus on the usage of serology tests and CT scans for COVID-19 diagnostics. Nearly all societies suggested to postpone elective procedures in patients with suspected or confirmed COVID-19 and recommended constant reevaluation of these patients. Additionally, we summarized recommendations focusing on precautions in the theater and the management of chest drains. This study provides a novel approach to informed guidance for thoracic surgeons during the COVID-19 pandemic in the absence of scientific evidence-based data

Body Mass Index Thresholds and the Use of Bariatric Surgery in the Field of Kidney Transplantation in Germany

Background: Obesity in the recipient is linked to inferior transplant outcome. Consequently, access to kidney transplantation (KT) is often restricted by body mass index (BMI) thresholds. Bariatric surgery (BS) has been established as a superior treatment for obesity compared to conservative measures, but it is unclear whether it is beneficial for patients on the waiting list. Methods: A national survey consisting of 16 questions was sent to all heads of German KT centers. Current situation of KT candidates with obesity and the status of BS were queried. Results: Center response rate was 100%. Obesity in KT candidates was considered an important issue (96.1%; n = 49/51) and 68.6% (n = 35/51) of departments responded to use absolute BMI thresholds for KT waiting list access with >= 35 kg/m(2) (45.1%; n = 23/51) as the most common threshold. BS was considered an appropriate weight loss therapy (92.2%; n = 47/51), in particular before KT (88.2%; n = 45/51). Sleeve gastrectomy was the most favored procedure (77.1%; n = 37/51). Twenty-one (41.2%) departments responded to evaluate KT candidates with obesity by default but only 11 (21.6%) had experience with >= n = 5 transplants after BS. Concerns against BS were malabsorption of immunosuppressive therapy (39.2%; n = 20/51), perioperative morbidity (17.6%; n = 9/51), and malnutrition (13.7%; n = 7/51). Conclusions: Obesity is potentially limiting access for KT. Despite commonly used BMI limits, only few German centers consider BS for obesity treatment in KT candidates by default. A national multicenter study is desired by nearly all heads of German transplant centers to prospectively assess the potentials, risks, and safety of BS in KT waitlisted patients

Recurrence at surgical margin following hepatectomy for colorectal liver metastases is not associated with R1 resection and does not impact survival.

BACKGROUND Resection margin status has traditionally been associated with tumor recurrence and oncological outcome following liver resection for colorectal liver metastases. Previous studies, however, did not address the impact of resection margin on the site of tumor recurrence and did not differentiate between true local recurrence at the resection margin and recurrence elsewhere in the liver. This study aimed to determine whether positive resection margins determine local recurrence and whether recurrence at the surgical margin influences long-term survival. METHODS Clinicopathological data and oncological outcomes of patients who underwent curative resection for colorectal liver metastases between 2012 and 2017 at 2 major hepatobiliary centers (Bern, Switzerland, and Berlin, Germany) were assessed. Cross-sectional imaging following hepatectomy was reviewed by radiologists in both centers to distinguish between recurrence at the resection margin, defined as hepatic local recurrence, and intrahepatic recurrence elsewhere. The association between surgical margin status and location of tumor recurrence was evaluated, and the impact on overall survival was determined. RESULTS During the study period, 345 consecutive patients underwent hepatectomy for colorectal liver metastases. Histologic surgical margins were positive for tumor cells (R1) in 63 patients (18%). After a median follow-up time of 34 months, tumor recurrence was identified in 154 patients (45%). Hepatic local recurrence was not detected more frequently after R1 than after R0 resection (P = .555). Hepatic local recurrence was not associated with worse overall survival (P = .436), while R1 status significantly impaired overall survival (P = .025). Additionally, overall survival was equivalent between patients with hepatic local recurrence and patients with any intrahepatic and/or extrahepatic recurrence. In patients with intrahepatic recurrence only, oncological outcomes improved if local hepatic therapy was possible (resection or ablation) in comparison to patients treated only with chemotherapy or best supportive care (3-year overall survival: 85% vs 39%; P < .0001). CONCLUSION The incidence of hepatic local recurrence after hepatectomy for colorectal liver metastases is independent of R1 resection margin status. Additionally, hepatic local recurrence at the resection margin is not associated with worse overall survival compared with any other intra- or extrahepatic recurrence. Therefore, R1 status at hepatectomy seems to be a surrogate factor for advanced disease without influencing location of recurrence and thereby oncological outcome. This finding may support decision-making when extending the indication for surgery in borderline resectable colorectal liver metastases

Minimal-Invasive Versus Open Hepatectomy for Colorectal Liver Metastases: Bicentric Analysis of Postoperative Outcomes and Long-Term Survival Using Propensity Score Matching Analysis.

Minimal-invasive hepatectomy (MIH) has been increasingly performed for benign and malignant liver lesions with most promising short-term results. However, the oncological role of MIH in the treatment of patients with colorectal liver metastases (CRLM) needs further investigation. Clinicopathological data of patients who underwent liver resection for CRLM between 2012 and 2017 at the Department of Surgery, Charité-Universitätsmedizin Berlin, and the Inselspital Bern were assessed. Postoperative outcomes und long-term survivals of patients following MIH were compared with those after conventional open hepatectomy (OH) after 1:1 propensity score matching. During the study period, 229 and 91 patients underwent liver resection for CRLM at the Charité Berlin and the Inselspital Bern, respectively. Patients who underwent MIH in one of the two centers (n = 69) were compared with a matched cohort of patients who underwent OH. MIH was associated with lower complication rates (23% vs. 44%, p = 0.011), shorter length of intensive care unit stay (ICU, 1 vs. 2 days, p = 0.043), shorter length of hospital stay (7 vs. 11 days, p < 0.0001), and a reduced need for intraoperative transfusions (12% vs. 25%, p = 0.047) compared to OH. R0 status was achieved in 93% and 75% of patients after MIH and OH, respectively (p = 0.005). After a median follow-up of 31 months, MIH resulted in similar five-year overall survival (OS) rate (56% vs. 48%, p = 0.116) in comparison to OH. MIH for CRLM is associated with lower postoperative morbidity, shorter length of ICU and hospital stay, reduced need for transfusions, and comparable oncologic outcomes compared to the established OH. Our findings suggest that MIH should be considered as the preferred method for the treatment of curatively resectable CRLM