Muskuläre Beanspruchung der unteren Lendenwirbelsäule sowie Arbeitsenergieumsatz unter Verwendung des "HAL for care support – Lumbar Type" bei repetetiven Hebevorgängen

Die Anwendung eines Exoskeletts stellt eine Möglichkeit dar, ein rückenschonendes Arbeiten zu ermöglichen. Ziel dieser Arbeit ist es, einen möglichen Einfluss des neuronal gesteuerten Exoskeletts (HAL) auf die autochthone Rückenmuskulatur zu untersuchen. 14 gesunde Probanden führten alternierend mit HAL bzw. ohne HAL einen Hebeversuch (17,5 kg) durch. Als Kennwerte der elektromyographischen Aktivität dienten der RMS-Wert sowie das integrierte EMG. Es konnte eine statistisch signifikante Reduktion des iEMG sowie des RMS im Bereich der TES und LES durch Anwendung des HAL nachgewiesen werden. Entsprechend zeigt die Anwendung des HAL eine Reduktion der muskulären Aktivität und Kraft. Die subjektive Erschöpfung wurde anhand der Borg-Skala sowie eines erstellten Fragebogens ermittelt und zeigte sich unbeeinflusst. Auch die kardiovaskulären Parameter sowie die mobile Spiroergometrie blieben unbeeinflusst

Secondary purulent infections of the elbow joint

$\bf Background$ Septic arthritis of the elbow joint is a rare condition. Limited data is available on infections of the elbow joint following trauma or prior surgery on this joint. The aim of this study was to describe the etiology, comorbidities, bacterial spectrum and therapy of secondary purulent elbow infections. $\bf Methods$ Patients treated in our hospital were selected through retrospective chart review between 2006 and 2015. We included all patients with an empyema of the elbow after a trauma or surgical intervention on this joint. 30 patients between 26 and 82 years (mean: 52.47) were included. $\bf Results$ Seven patients (23.3%) were female, 23 (76.7%) male. 22 patients (73.3%) had a history of trauma, eight (26.7%) had prior elective surgeries on their elbow. Between one and 25 surgeries (mean: 5.77) were necessary for treatment. In nine patients, debridement and synovectomy were sufficient, eight patients (26.7%) received resection of the elbow joint. One patient was treated with a chronic fistula. In 18 patients (60%), cultures of aspiration/intraoperative swabs were positive for $\textit {Staphylococcus aureus}$, four of these were methicillin-resistant. Four patients (13.3%) had positive cultures for $\textit {Staphylococcus epidermidis}$, in five patients (16.7%) no bacteria could be cultured. $\bf Conclusions$ Secondary infections of the elbow joint are a rare disease with potentially severe courses, requiring aggressive surgical treatment and possibly severely impacting elbow function. $\textit {Staphylococcus aureus}$ was the most common bacteria in secondary infections and should be addressed by empiric antibiotic treatment when no suspicion for other participating organisms is present

Superior enhancement of cutaneous microcirculation due to "cyclic" application of a negative pressure wound therapy device in humans

$\bf Objectives:$ Despite a common utilization of "Negative Pressure Wound Therapy" (NPWT) Devices in a wide range of specialties, some of the basic mechanisms of action of the techniques are still on debate. Conflicting results from prior studies demonstrate our lack of understanding how wound-bed perfusion or cutaneous microcirculation is affected by NPWT. $\bf Methods:$ We conducted a prospective randomized study which included 45 healthy subjects to further investigate the acute effects of NPWT on cutaneous microcirculation underneath the applied dressing. Three modes of application, namely, continuous, intermittent, cyclic, were tested. Amongst others, measurements of elicited surface pressure and a comprehensive microcirculatory analysis were carried out by utilizing an O2C-device. For the detection of (systemic) remote effects, perfusion changes of the contra-lateral thigh were evaluated. $\bf Results:$ All three tested modes of application led to a significant ($\it p$ < 0.05) improvement in local tissue perfusion with an increased blood flow of max +151% and tissue oxygen saturation of +28.2% compared to baseline values. Surface pressure under the dressing significantly increased up to 29.29 mmHg due to the activation of the NPWT device. Continuous, intermittent, and cyclic application of negative pressure were accurately sensed by participants, resulting in reported pain values that mirrored the different levels of applied suction. Although the cyclic application mode showed the most pronounced effects regarding microcirculatory changes, no statistical significance between groups was observed. $\bf Conclusion:$ We could demonstrate a significant improvement of cutaneous microcirculation under an applied NPWT dressing with favorable effects due to cyclic mode of application. An increased surface pressure leads to a better venous drainage of the tissue, which was shown to increase arterial inflow with a consecutive improvement of oxygen supply. Further research is warranted to evaluate our findings regarding wound bed perfusion in the clinical field with respect to formation of granulation tissue and wound healing

Autologous vs. implant-based breast reconstruction after skin- and nipple-sparing mastectomy

$\bf Introduction:$ Autologous (ABR) and implant-based breast reconstruction (IBR) represent the most common procedures after skin- and nipple-sparing mastectomy. This cross-sectional study is a comprehensive analysis of ABR and IBR considering surgical and patient-reported outcomes. $\textbf {Patients and methods:}$ Eligible patients underwent breast reconstruction (ABR and IBR) after skin- and nipple-sparing mastectomy between January 2014 and December 2020. Outcome parameters included quality of life (European Organisation for Research and Treatment of Cancer - EORTC - QLQ30, BR23, Breast-Q, CES-D), complication rates, aesthetic result, and breast sensitivity. $\bf Results:$ 108 patients participated in the study (IBR: $\it n$ = 72, age 48.9 $\pm$ 9.9 years; ABR: $\it n$ = 36, age: 46.6 $\pm$ 7.3 years). Mean follow-up was 27.1 $\pm$ 9.3 (IBR) and 34.9 $\pm$ 20.5 (ABR), respectively. IBR patients suffered significantly more often from major complications (30.6% vs. 8.3%; $\it p$ = 0.01), while ABR patients underwent secondary procedures significantly more often to improve the aesthetic result (55.6% vs. 29.2%, $\it p$ = 0.004). Unilateral reconstructions revealed superior aesthetic results in ABR (n.s.), while in bilateral reconstruction IBR tended to score higher (n.s.). Scar evaluation resulted in a better result of IBR in both categories ($\it p$ < 0.01). Breast sensitivity was severely impaired in both groups. The Breast-Q revealed a significantly higher "patient satisfaction with breast" after ABR ($\it p$ = 0.033), while the other QoL-tests and subscales showed no significant differences between the two procedures. $\bf Conclusion:$ ABR is associated with a higher patient satisfaction despite the high probability of secondary procedures to improve the aesthetic outcome, whereas IBR-patients suffer more often from major complications. Furthermore, the laterality of reconstruction should be included in the individual decision-making process

Functional outcome of traumatic spinopelvic instabilities treated with lumbopelvic fixation

The aim of this study was to assess the functional outcome after lumbopelvic fixation (LPF) using the SMFA (short musculoskeletal functional assessment) score and discuss the results in the context of the existing literature. The last consecutive 50 patients who underwent a LPF from January 1st 2011 to December 31st 2014 were identified and administered the SMFA-questionnaire. Inclusion criteria were: (1) patient underwent LPF at our institution, (2) complete medical records, (3) minimum follow-up of 12 months. Out of the 50 recipients, 22 questionnaires were returned. Five questionnaires were incomplete and therefore seventeen were included for analysis. The mean age was 60.3 years (32–86 years; 9m/8f) and the follow-up averaged 26.9 months (14–48 months). Six patients (35.3%) suffered from a low-energy trauma and 11 patients (64.7%) suffered a high-energy trauma. Patients in the low-energy group were significantly older compared to patients in the high-energy group (72.2 vs. 53.8 years; $\it {p}$ = 0.030). Five patients (29.4%) suffered from multiple injuries. Compared to patients with low-energy trauma, patients suffering from high-energy trauma showed significantly lower scores in "daily activities" (89.6 vs. 57.1; $\it {p}$ = 0.031), “mobility” (84.7 vs. 45.5; $\it {p}$ = 0.015) and "function" (74.9 vs. 43.4; $\it {p}$ = 0.020). Our results suggest that patients with older age and those with concomitant injuries show a greater impairment according to the SMFA score. Even though mostly favorable functional outcomes were reported throughout the literature, patients still show some level of impairment and do not reach normative data at final follow-up

Inhibition of pathological increased matrix metalloproteinase (MMP) activity for improvement of bone regeneration in diabetes

Patients with diabetes suffer from poor fracture healing. Molecular reasons are not fully understood and our previous gene expression microarray analyses of regenerating bones from mice with type 2 diabetes (db$^{−}$/db$^{−}$) revealed accelerated activation of pathways concerning matrix metalloproteases (MMPs). Thus, we picked out the pathological MMP acceleration as a target for profound gene expression analyses and additional therapeutic intervention in the present study. In the first part, gene expression of ECM degrading proteinases and inhibitors was investigated three and seven days postoperatively. $\it Mmp3$, $\it Mmp9$, $\it Mmp13$ and gene expression of MMP inhibitor $\it Timp2$ was significantly higher in regenerating bone fractures of db$^{−}$/db$^{−}$ compared to wild type animals. $\it Timp1$ and metalloproteinase $\it AdamTS4$ showed no differences. In the second part, we locally applied a single dose (1 $\mu$L of 5 $\mu$M solution) of the broad-spectrum molecular MMP inhibitor Marimastat on tibial defects in db$^{−}$/db$^{−}$. We performed immunohistochemical and histological stainings seven days post operation. Impaired bone healing, collagen content, angiogenesis, and osteoclast invasion in db$^{−}$/db$^{−}$ were restored significantly by application of Marimastat compared to PBS controls ($\it n$ = 7/group). Hence, local intervention of bone defects by the molecular MMP inhibitor Marimastat might be an alternative therapeutic intervention for bone healing in diabetes

Posttraumatic lymphedema after open fractures of the lower extremity

Secondary lymphedema is a very common clinical issue with millions of patients suffering from pain, recurrent skin infections, and the constant need for a decongestive therapy. Well-established as a consequence of oncologic procedures, secondary lymphedema is also a well-known phenomenon after trauma. However, precise epidemiological data of lymphedema progress upon severe extremity injuries are still missing. In the present work, we analyzed a patient cohort of 94 individuals who suffered open fractures of the lower extremity and soft tissue injury, of 2nd and 3rd grade according to Tscherne classification, between 2013 and 2019. Typical symptoms of lymphedema have been obtained via interviews and patient medical records in a retrospective cohort analysis. Of all patients, 55% showed symptoms of secondary lymphedema and 14% reported recurrent skin infections, indicating severe lymphedema. Furthermore, comparing patients with and without lymphedema, additional parameters, such as obesity, total number of surgeries, infections, and compartment syndrome, related to lymphedema progress could be identified. According to these data, posttraumatic secondary lymphedema has a highly underestimated clinical prevalence. Further prospective studies are needed to validate this first observation and to identify high-risk groups in order to improve patient's health care

Deficiency of myostatin protects skeletal muscle cells from ischemia reperfusion injury

Ischemia reperfusion (IR) injury plays a pivotal role in many diseases and leads to collateral damage during surgical interventions. While most studies focus on alleviating its severity in the context of brain, liver, kidney, and cardiac tissue, research as regards to skeletal muscle has not been conducted to the same extent. In the past, myostatin (MSTN), primarily known for supressing muscle growth, has been implicated in inflammatory circuits, and research provided promising results for cardiac IR injury mitigation by inhibiting MSTN cell surface receptor ACVR2B. This generated the question if interrupting MSTN signaling could temper IR injury in skeletal muscle. Examining human specimens from free myocutaneous flap transfer demonstrated increased MSTN signaling and tissue damage in terms of apoptotic activity, cell death, tissue edema, and lipid peroxidation. In subsequent in vivo Mstn$_{Ln/Ln}$ IR injury models, we identified potential mechanisms linking MSTN deficiency to protective effects, among others, inhibition of p38 MAPK signaling and SERCA2a modulation. Furthermore, transcriptional profiling revealed a putative involvement of NK cells. Collectively, this work establishes a protective role of MSTN deficiency in skeletal muscle IR injury

A highly reliable convolutional neural network based soft tissue sarcoma metastasis detection from chest x-ray images

Introduction: soft tissue sarcomas are a subset of malignant tumors that are relatively rare and make up 1% of all malignant tumors in adulthood. Due to the rarity of these tumors, there are significant differences in quality in the diagnosis and treatment of these tumors. One paramount aspect is the diagnosis of hematogenous metastases in the lungs. Guidelines recommend routine lung imaging by means of X-rays. With the ever advancing AI-based diagnostic support, there has so far been no implementation for sarcomas. The aim of the study was to utilize AI to obtain analyzes regarding metastasis on lung X-rays in the most possible sensitive and specific manner in sarcoma patients. Methods: a Python script was created and trained using a set of lung X-rays with sarcoma metastases from a high-volume German-speaking sarcoma center. 26 patients with lung metastasis were included. For all patients chest X-ray with corresponding lung CT scans, and histological biopsies were available. The number of trainable images were expanded to 600. In order to evaluate the biological sensitivity and specificity, the script was tested on lung X-rays with a lung CT as control. Results: in this study we present a new type of convolutional neural network-based system with a precision of 71.2%, specificity of 90.5%, sensitivity of 94%, recall of 94% and accuracy of 91.2%. A good detection of even small findings was determined. Discussion: the created script establishes the option to check lung X-rays for metastases at a safe level, especially given this rare tumor entity