Surgeon experience with dynamic intraligamentary stabilization does not influence risk of failure

Purpose

Studies on dynamic intraligamentary stabilization (DIS) of acute anterior cruciate ligament (ACL) ruptures reported failure rates similar to those of conventional ACL reconstruction. This study aimed to determine whether surgeon experience with DIS is associated with revision rates or patient-reported outcomes. The hypothesis was that more experienced surgeons achieved better outcomes following DIS due to substantial learning curve.

Methods

The authors prospectively enrolled 110 consecutive patients that underwent DIS and evaluated them at a minimum of 2 years. The effects of independent variables (surgeon experience, gender, age, adjuvant procedures, tear location, preinjury Tegner score, time from injury to surgery, and follow-up) on four principal outcomes (revision ACL surgery, any re-operation, IKDC and Lysholm score) were analyzed using univariable and multivariable regressions.

Results

From the 110 patients enrolled, 14 patients (13%) were lost to follow-up. Of the remaining 96 patients, 11 underwent revision ACL surgery, leaving 85 patients for clinical assessment at a mean of 2.2?±?0.4 years (range 2.0–3.8). Arthroscopic reoperations were performed in 26 (27%) patients, including 11 (11%) revision ACL surgeries. Multivariable regressions revealed: (1) no associations between the reoperation rate and the independent variables, (2) better IKDC scores for ‘designer surgeons’ (b?=?10.7; CI 4.9–16.5; p?<?0.001), higher preinjury Tegner scores (b?=?2.5, CI 0.8–4.2; p?=?0.005), and younger patients (b?=?0.3, CI 0.0–0.6; p?=?0.039), and (3) better Lysholm scores for ‘designer surgeons’ (b?=?7.8, CI 2.8–12.8; p?=?0.005) and preinjury Tegner score (b?=?1.9, CI 0.5–3.4; p?=?0.010).

Conclusion

Surgeon experience with DIS was not associated with rates of revision ACL surgery or general re-operations. Future, larger-scaled studies are needed to confirm these findings. Patients operated by ‘designer surgeons’ had slightly better IKDC and Lysholm scores, which could be due to better patient selection and/or positively biased attitudes of both surgeons and patients.

Level of evidence

Level II, prospective comparative study.

     

Comparing the ultrastructural effects of two different cardiac preparation- and perfusion-techniques in a porcine model of extracorporal long-term preservation.

OBJECTIVE: In heart transplantation a well-preserved myocardial ultrastructure is an important precondition for functional regeneration. Aim of the study is to optimize the conditions in this new established model of extracorporeal cardiac perfusion. METHODS: (I) In six pigs, hearts were arrested with Bretschneider Histidine-Tryptophan-Ketoglutarate cardioplegia and cold ischemia, explanted and connected to a circulating constant pressure Langendorff system (80-90mmHg) and perfused with leukocyte depleted autologous blood. (II) Beating hearts of seven pigs were explanted and connected immediately to the Langendorff system (40-50mmHg). Myocardial biopsies (n=55) were taken in situ and during the following 12h of reperfusion, and were prepared for electron microscopy. RESULTS: Cardioplegia and hypothermia (group I) induced mitochondrial edema and myofibrillar degeneration in cardiomyocytes and severe endothelial edema. During 4h of reperfusion, mitochondrial edema, myofibrillar, and sarcolemmal damages in cardiomyocytes increased. Moderate endothelial degeneration, interstitial edema, and bleedings appeared. In contrast, in group II after 6h of reperfusion endothelia showed only mild alterations. Cardiomyocytes showed myofibrillary but not mitochondrial degeneration. Interstitial edema and bleedings were mild. CONCLUSION: Avoiding cardioplegia and hypothermia, and using lower perfusion pressure resulted in a better preservation of the ultrastructure in explanted hearts at the Langendorff system.     

Mental distress among young adults in Great Britain: long-term trends and early changes during the COVID-19 pandemic

Purpose

In Great Britain, few studies documented mental health trends in young adults in the years preceding 2020, the mental health dimensions affected, and how these compare with changes observed during the COVID-19 pandemic.

Methods

Long-term trends in mental health among 16–34 year old men and women between 1991 and 2018, and changes between 2018–19 and July–September 2020 were examined using all waves from the British Household Panel Study (1991–2008), the UK Household Longitudinal Study (2009–20), and the first five UKHLS COVID-19 waves administered in April, May, June, July, and September 2020. Findings are based on the GHQ-12 continuous score (0–36), clinically significant cases (4 + /12) and severe cases (7 + /12) for mental distress, and item endorsements.

Results

Between 1991 and 2018, the prevalence of cases (4 + /12) increased from 14–22% to 19–32% across groups. Increases were largest in women aged 16–24. In April 2020, the risk of caseness (4 + /12) increased across groups by 55% to 80% compared to the 2018–19 baseline. This increase, however, rapidly diminished over time: in July–September 2020, there was only a higher risk of caseness (4 + /12) in men aged 25–34 (prevalence ratio = 1.29, 95% CI 1.01–1.65) compared to the 2018–19 baseline.

Conclusion

Whereas distress surged in April 2020, its return to pre-pandemic levels by September 2020 highlights the nuanced impact that the pandemic may have over time. Given the magnitude of the decline in mental health over the past decade, attention must be given to young adults once the pandemic ends.

     

Acquiring basic endoscopy skills by training on the GI Mentor II

Background Achieving proficiency in flexible endoscopy requires a great amount of practice. Virtual reality (VR) simulators could provide an effective alternative for clinical training. This study aimed to gain insight into the proficiency curve for basic endoscope navigation skills with training on the GI Mentor II. Methods For this study, 30 novice endoscopists performed four preset training sessions. In each session, they performed one EndoBubble task and managed multiple VR colonoscopy cases (two in first session and three in subsequent sessions). Virtual reality colonoscopy I-3 was repeatedly performed as the last VR colonoscopy in each session. The assignment for the VR colonoscopies was to visualize the cecum as quickly as possible without causing patient discomfort. Five expert endoscopists also performed the training sessions. Additionally, the performance of the novices was compared with the performance of 20 experienced and 40 expert endoscopists. Results The novices progressed significantly, particularly in the time required to accomplish the tasks (p < 0.05, Friedman’s analysis of variance [ANOVA], p < 0.05, Wilcoxon signed ranks). The experts did not improve significantly, except in the percentage of time the patient was in excessive pain. For all the runs, the performance of the novices differed significantly from that of both the experienced and the expert endoscopists (p < 0.05, Mann–Whitney U). The performance of the novices in the latter runs differed less from those of both the experienced and the expert endoscopists. Conclusions The study findings demonstrate that training in both VR colonoscopy and EndoBubble tasks on the GI Mentor II improves the basic endoscope navigation skills of novice endoscopists significantly.     

The fracture and osteoporosis clinic: 1-year results and 3-month compliance

INTRODUCTION: A Fracture and Osteoporosis (F&O) clinic started in two major general hospitals in the South of the Netherlands on April 1st 2004. Its objectives were to perform easy and complete assessment of female and male patients aged 50 years and over, initially treated for a low-energy trauma fracture, and to evaluate its effectiveness for early diagnosis and treatment of osteoporosis. METHODS: All eligible patients were selected from the digital X-ray system of the Emergency Department. DXA-scans and, if indicated, spinal radiographs were made. If osteoporosis was diagnosed, the F&O nurse explained the treatment strategy. Treatment advice was sent to the general practitioner (GP), who prescribed medication and provided further support. After 3 months, all osteoporosis patients received a compliance and side effects follow-up questionnaire. RESULTS: Up to June 1st 2005, 1058 patients followed the diagnostic procedure; 584 patients did not. Three times more women (804) than men (254) suffered a fracture. Osteoporosis occurred 10% more often in women. Overall, 37.1% had osteoporosis, based on DXA-scan only, and 39.6% when spinal radiographs were added. Spinal radiographs of the thoracic and or lumbar spine were made in 166 patients, radiographs of the thorax in 114 patients. Overall, fractures of the wrist were most common, with fractures of the hand occurring most frequently in men (20.0%). All fracture sites, except foot and clavicula, were associated with a higher frequency of osteoporosis than in the Dutch population. The response rate to the 3-month compliance questionnaire was 73% increasing to 96% after telephone contact. 86% visited their GP; 11% did not because they already received anti-osteoporotic medication prior to the fracture. Bisphosphonates were prescribed to 84% and discontinued by 7%. 13% reported side effects of bisphosphonates. Only half of the patients received the recommended calcium supplementation. CONCLUSIONS: The F&O clinic with its digital X-ray system facilitated easy, complete identification of fracture patients and early treatment of osteoporosis, which was frequently diagnosed. Self-reported compliance was high.     

Immune synapse formation determines interaction forces between T cells and antigen-presenting cells measured by atomic force microscopy

During adaptive immune responses, T lymphocytes recognize antigenic peptides presented by MHC molecules on antigen-presenting cells (APCs). This recognition results in the formation of a so-called immune synapse (IS) at the T-cell/APC interface, which is crucial for T-cell activation. The molecular composition of the IS has been extensively studied, but little is known about the biophysics and interaction forces between T cells and APCs. Here, we report the measurement of interaction forces between T cells and APCs employing atomic force microscopy (AFM). For these investigations, specific T cells were selected that recognize an antigenic peptide presented by MHC-class II molecules on APCs. Dynamic analysis of T-cell/APC interaction by AFM revealed that in the presence of antigen interaction forces increased from 1 to 2 nN at early time-points to a maximum of ≈14 nN after 30 min and decreased again after 60 min. These data correlate with the kinetics of synapse formation that also reached a maximum after 30 min, as determined by high-throughput multispectral imaging flow cytometry. Because the integrin lymphocyte function antigen-1 (LFA-1) and its counterpart intercellular adhesion molecule-1 (ICAM-1) are prominent members of a mature IS, the effect of a small molecular inhibitor for LFA-1, BIRT377, was investigated. BIRT377 almost completely abolish the interaction forces, emphasizing the importance of LFA-1/ICAM-1-interactions for firm T-cell/APC adhesion. In conclusion, using biophysical measurements, this study provides precise values for the interaction forces between T cells and APCs and demonstrates that these forces develop over time and are highest when synapse formation is maximal.Cell-cell contacts play a crucial role in triggering the body''s immune system. During adaptive immune responses, antigen-presenting cells (APCs) process foreign antigens into peptides, which are loaded into major histocompatibility complex (MHC) molecules. T cells patrolling the body scan APC and establish intercellular contacts when their antigen-specific T-cell receptors (TCR) recognize a foreign peptide/MHC complex on the APC. Elegant two-photon microscopy studies have revealed the dynamics of this process in lymph nodes. There, T cells move through the network of dendritic cells (DCs) and scan DCs for foreign antigen. In the absence of antigen brief transient interactions are observed, whereas upon recognition of a cognate antigen T cells are arrested and interactions prolonged to >1 h (1, 2). Similarly, during antibody responses, long-lasting antigen driven interactions between T helper cells and B cells have been observed in lymph nodes (3). Subsequently, at the contact zone between T cells and APC spatially organized molecular clusters develop, referred to as immune synapse (IS), which is crucial for T-cell activation and effector cells development (4).Formation of an IS includes the coordinated translocation of several protein complexes, among others TCR and its ligand pMHC, and the integrin lymphocyte function-associated antigen-1 (LFA-1) and its counterpart intercellular adhesion molecule 1 (ICAM-1). This orchestrated reorganization of membrane proteins involves many cytoplasmic molecules and is presumably supported by cytoskeletal factors like actin (5). Although many important aspects of IS formation have been identified, little is known about the underlying biophysics and interaction forces between T cells and APCs. Integrins represent a family of major cell adhesion proteins used by cells to tune their adhesion propensity. This tuning is achieved by controlling the number of proteins present at the cell''s interaction face and by the activation state of the adhesion proteins themselves. Switch blade-type heterodimeric integrins are known to exist in different activation states, which are transmitted from the cytoplasmic tail to the extracellular domain (6). It is believed that activation state changes are triggered by inside-out-signaling, for instance when a TCR recognizes a peptide presented by MHC molecules (7). The activation of LFA-1 upon TCR-triggering is mainly mediated by PKC and the small GTPases Ras and Rap1 [(8) and references therein]. The association of actin to LFA-1 accompanies this process. Subsequent motor protein motion yields a cytoskeleton contraction, which exerts low forces on LFA-1 to induce occupied integrin activation and to fully arrest the two cells for adhesion. By actio et reactio, this force has to be counterbalanced on the APC side, resulting in a high interaction force between T cells and APCs.Cell–cell adhesion has been studied by micropipette aspiration techniques (9, 10) and atomic force microscopy (AFM) (11–13). The recent years have seen a significant increase of AFM-related studies in biological systems, and single-cell force spectroscopy (SCFS) by AFM has been established as an important tool for the study of cell adhesion (14). This technique allows for the analysis of adhesion processes and adhesion forces under near-physiological conditions. To the best of our knowledge, the interaction forces between T cells and APC have not yet been investigated by SCFS. In the present study, we have modified and adjusted SCFS techniques for the measurement of long-time interaction forces between T cells and APC. These force spectroscopy measurements were complemented by conjugate and high-throughput fluorescence assays relating the kinetics of IS formation to the development of interaction forces between T cells and APCs.     

Extensive jejunal diverticulosis in a family, a matter of inheritance?

Diverticulosis of the jejunum is a rare finding (0.06 to 1.3%). Possible complications are bacterial overgrowth, malabsorption, bleeding, mechanical obstruction, volvulus and perforation. At present only one case report on familial jejunal diverticulosis has been published. We describe three patients with jejunal diverticulosis within one family, which might suggest inheritance.