Spectral properties of a short-range impurity in a quantum dot

The spectral properties of the quantum mechanical system consisting of a quantum dot with a short-range attractive impurity inside the dot are investigated in the zero-range limit. The Green function of the system is obtained in an explicit form. In the case of a spherically symmetric quantum dot, the dependence of the spectrum on the impurity position and the strength of the impurity potential is analyzed in detail. It is proven that the confinement potential of the dot can be recovered from the spectroscopy data. The consequences of the hidden symmetry breaking by the impurity are considered. The effect of the positional disorder is studied.Comment: 30 pages, 6 figures, Late

Surgical resection is superior to TACE in the treatment of HCC in a well selected cohort of BCLC-B elderly patients—A retrospective observational study

Simple Summary Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. Liver transplantation (LT) and surgical resection (SR) are currently the primary treatments with curative intent. Nevertheless, more than two-thirds of patients are elderly and, therefore, excluded from LT; while, according to the Barcelona Clinic Liver Cancer (BCLC) system, SR should only be offered to a small group of patients with early stage HCC. The identification in stage B of an intermediate subgroup of patients that fulfill the criteria for surgery may play an important role in the implementation of potentially curative treatments. Hepatocellular carcinoma (HCC) usually develops in cirrhotic liver, with high recurrence rates. However, considering its increasing detection in non-cirrhotic liver, the choice of treatment assumes particular relevance. This study aimed to investigate outcomes of patients among BCLC stages and enrolled for surgical resection (SR) according to a more complex evaluation, to establish its safety and efficacy. A total of 186 selected HCC patients (median age 73.2 yrs), submitted to SR between January 2005 and January 2021, were retrospectively analyzed. Of which, 166 were staged 0, A, B according to the BCLC system, while 20 with a single large tumor (>5 cm) were classified as stage AB. No perioperative mortality was recorded; complications occurred in 48 (25.80%) patients, and all but two were Clavien-Dindo grade I-II. Median follow-up was 9.2 years. Subsequently, 162 recurrent patients (87,1%) were selected for new treatments. Comparable overall survival rates (OS) were observed at 1, 3, 5, and 10 years in 0, A, B and AB stages (p = 0.2). Eventually, the BCLC-B group was matched to 40 BCLC-B patients treated (2015-2021) with TACE. Significant differences in baseline characteristics (p <0.0001) and in OS were observed at 1 and 3 years (p <0.0001); a significant difference was also observed in oncological outcomes, in terms of the absence, residual, or relapse of disease (p <0.05). Surgery might be a valid treatment in HCC for patients affected by chronic liver disease in a condition of compensation, up to BCLC-B stage. Surgical indication for liver resection in case of HCC should be extensively revised

The weekend effect on the provision of Emergency Surgery before and during the COVID-19 pandemic: case–control analysis of a retrospective multicentre database

Introduction: The concept of “weekend effect”, that is, substandard healthcare during weekends, has never been fully demonstrated, and the different outcomes of emergency surgical patients admitted during weekends may be due to different conditions at admission and/or different therapeutic approaches. Aim of this international audit was to identify any change of pattern of emergency surgical admissions and treatments during weekends. Furthermore, we aimed at investigating the impact of the COVID-19 pandemic on the alleged “weekend effect”. Methods: The database of the CovidICE-International Study was interrogated, and 6263 patients were selected for analysis. Non-trauma, 18+ yo patients admitted to 45 emergency surgery units in Europe in the months of March–April 2019 and March–April 2020 were included. Demographic and clinical data were anonymised by the referring centre and centrally collected and analysed with a statistical package. This study was endorsed by the Association of Italian Hospital Surgeons (ACOI) and the World Society of Emergency Surgery (WSES). Results: Three-quarters of patients have been admitted during workdays and only 25.7% during weekends. There was no difference in the distribution of gender, age, ASA class and diagnosis during weekends with respect to workdays. The first wave of the COVID pandemic caused a one-third reduction of emergency surgical admission both during workdays and weekends but did not change the relation between workdays and weekends. The treatment was more often surgical for patients admitted during weekends, with no difference between 2019 and 2020, and procedures were more often performed by open surgery. However, patients admitted during weekends had a threefold increased risk of laparoscopy-to-laparotomy conversion (1% vs. 3.4%). Hospital stay was longer in patients admitted during weekends, but those patients had a lower risk of readmission. There was no difference of the rate of rescue surgery between weekends and workdays. Subgroup analysis revealed that interventional procedures for hot gallbladder were less frequently performed on patients admitted during weekends. Conclusions: Our analysis revealed that demographic and clinical profiles of patients admitted during weekends do not differ significantly from workdays, but the therapeutic strategy may be different probably due to lack of availability of services and skillsets during weekends. The first wave of the COVID-19 pandemic did not impact on this difference

Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

Trans-vaginal repair of recurrent rectovaginal fistula with interposition of BIO-A Tissue Reinforcement

Rectovaginal fistulas (RVFs) represent the majority of all symptomatic leakages after anterior and low anterior resection in women. Conservative management is useful in paucisymptomatic patients with small fistulas but is usually unsuccessful in all other cases. The surgical strategies are various and heavily dependent on the type and extent of anatomic involvement. We present a case of a 51-year-old female with a multi-recurrent rectovaginal fistula that occurred since a laparoscopic sigmoidectomy was performed for a complicated diverticular disease in May 2015. An attempt to close the fistula was undertaken three times. In July 2019, a transvaginal repair was performed with interposition in the rectovaginal septum of GORE® BIO-A® Tissue Reinforcement. The postoperative course was uneventful. There was no recurrence and functional outcome was good at 24-months follow-up. Rectovaginal fistula can be successfully treated using the interposition of a GORE® BIO-A® Tissue Reinforcement with significant economic savings and good functional outcomes even through a transvaginal approach. It represents a therapeutic option for an otherwise difficult-to-treat complex fistula

[Nonspecific osteomyelitis in childhood and adolescence. The contribution of imaging diagnosis].

Nonspecific osteomyelitis in children and adolescents can be diagnosed in patients 2 to 16 years old and may present as acute, subacute or chronic. During the last 9 years, 40 pediatric patients (aged 2 to 16 years) affected with extra-axial inflammatory bone lesions were examined. The series of cases was then reviewed. This work was aimed at investigating the role of various imaging modalities: conventional radiology (CR), bone scan with technetium-99 methylene diphosphonate (99mTc-MDP), scintigraphy with technetium-esamethylpropylenaminoxima labelled leukocytes (99mTc-HMPAO), computed tomography (CT) and magnetic resonance imaging (MRI) were used to detect the lesions, to make a differential diagnosis and to assess different disease stages. As for acute osteomyelitis (6 patients), CR showed a lytic lesion, periosteal new bone and soft tissue swelling in 4/6 patients; no abnormalities were demonstrated in the other two. Bone scan, CT and MRI depicted bone involvement. CT and MRI also showed inflammatory lesion spread to surrounding soft tissue. 99mTc-HMPAO scintigraphy was not performed in acute osteomyelitis, because of technical difficulties in performing the exam promptly; thus, the early diagnosis of lesion nature was made with bone biopsy. As for subacute osteomyelitis (23 patients), 99mTc-HMPAO scintigraphy was performed in 8/23 patients and proved to be a highly sensitive method, showing cell clusters and confirming the diagnosis of inflammatory lesion. MRI showed a focal area of intermediate-low signal intensity on T1-weighted sequences, with small focal intralesional areas of low intensity, a low-signal perifocal rim and diffusely low signal of surrounding bone marrow. T2-weighted images showed high signal intensity in both the abscess lesion and bone marrow, the latter probably due to edema. In 5 patients, a paramagnetic contrast agent (Gd-DTPA) was administered during MRI and showed inhomogeneous enhancement of both the inflammatory lesion and surrounding bone marrow. As for chronic osteomyelitis (7 patients), MRI was performed in 5/7 patients. In 4 patients the lesion appeared as a low-signal area on T1-weighted images while T2-weighted images showed an inhomogeneous high-signal area. In the same patients, 99mTc-HMPAO scintigraphy was always positive. In patient 5, the lesion was represented by a low-signal area on both T1 and T2-weighted images, while 99mTc-HMPAO was negative. Therefore, in chronic osteomyelitis, both MRI and 99mTc-HMPAO were useful in detecting both spinal and peripheral bone involvement, which was in some cases asymptomatic at first observation CR, CT (3/4) and MR (4/4) findings extra-axial localizations were similar to those in subacute-chronic forms