Raymund E. Horch

Plastic and Hand Surgery, Friedrich-Alexander University Erlangen-Nuernberg Germany
{{numberWithCommas(270)}} Publications

Bone Structure Analysis of the Radius Using Ultrahigh Field (7T) MRI: Relevance of Technical Parameters and Comparison with 3T MRI and Radiography

Bone fractal signature analysis (FSA—also termed bone texture analysis) is a tool that assesses structural changes that may relate to clinical outcomes and functions. Our aim was to compare bone texture analysis of the distal radius in patients and volunteers using radiography and 3T and 7T magnetic resonance imaging (MRI)—a patient group (n = 25) and a volunteer group (n = 25) were included. Participants in the patient group had a history of chronic wrist pain with suspected or confirmed osteoarthritis and/or ligament instability. All participants had 3T and 7T MRI including T1-weighted turbo spin echo (TSE) sequences. The 7T MRI examination included an additional high-resolution (HR) T1 TSE sequence. Radiographs of the wrist were acquired for the patient group. When comparing patients and volunteers (unadjusted for gender and age), we found a statistically significant difference of horizontal and vertical fractal dimensions (FDs) using 7T T1 TSE-HR images in low-resolution mode (horizontal: p = 0.04, vertical: p = 0.01). When comparing radiography to the different MRI sequences, we found a statistically significant difference for low- and high-resolution horizontal FDs between radiography and 3T T1 TSE and 7T T1 TSE-HR. Vertical FDs were significantly different only between radiographs and 3T T1 TSE in the high-resolution mode; FSA measures obtained from 3T and 7T MRI are highly dependent on the sequence and reconstruction resolution used, and thus are not easily comparable between MRI systems and applied sequences.

Die Auswirkungen der SARS-CoV-2-Einschränkungen auf die Patientenversorgung im Fachbereich für Plastische, Rekonstruktive und Ästhetische Chirurgie

Zusammenfassung Hintergrund Im Rahmen der SARS-CoV-2-Pandemie wurde zur Bewältigung der erwarteten COVID-19-Patienten eine Reduktion der ambulanten und stationären elektiven Patientenbehandlung an den dafür vorgesehenen Kliniken gefordert. Je nach örtlichen Gegebenheiten und Versorgungsauftrag kam es während der SARS-CoV-2-Restriktionen zu unterschiedlichen Auswirkungen auf die Patientenversorgung. Betrachtet werden sollte der Anteil der notwendigen Versorgungsleistungen während der SARS-CoV-2-Restriktionen in einer Plastischen Chirurgie einer Großklinik. Methode Untersucht wurde die OP-Auslastung einer Abteilung für Plastische Chirurgie einer universitären Klinik im Zeitraum vom 16.03.2020 bis 27.04.2020. Diese Daten wurden mit Daten desselben Zeitraumes der Jahre 2017–2019 verglichen. Ergebnisse Auf Grund des vollständigen Stopps an elektiven Operationen kam es in dem Zeitraum der Restriktionen zu einer OP-Auslastung von 57,3 % verglichen mit den Jahren zuvor. Das Verhältnis von notfallmäßigen (2020: 56,4 %; 2017–2019: 54,9 %) und dringlichen (2020: 44,6 %; 2017–2019: 45 %) Operationen zu der Gesamtanzahl an OPs zeigte keine deutliche Veränderung. Des Weiteren zeigten sich keine ausschlaggebenden Unterschiede der verhältnismäßigen Verteilung der notfallmäßigen und dringlichen Operationen bezogen auf die Plastisch-Chirurgischen Teilbereiche, die Verletzungsursache oder den Versicherungsstatus (BG/Nicht-BG). Zusammenfassung Auf Grund der vorliegenden Daten kann die Relevanz des Fachgebiets für die allgemeine Patientenversorgung belegt werden. Daraus ergibt sich eine eindeutige Erforderlichkeit der Vorhaltung von Plastisch-Chirurgischen OP-Kapazitäten und Infrastrukturen auch während Krisenzeiten.

Tissue Viability of Free Flaps after Extracorporeal Perfusion Using a Modified Hydroxyethyl Starch Solution

Background: In free flap surgery, tissue is stored under hypothermic ischemia. Extracorporeal perfusion (EP) has the potential to extend storage time and the tissue’s perspective of survival. In the present study, the aim is to improve a recently established, simplified extracorporeal perfusion system. Methods: Porcine musculus rectus abdominis were stored under different conditions. One group was perfused continuously with a simplified one-way perfusion system for six hours, while the other received only a single flush but no further treatment. A modified hydroxyethyl starch solution was used as a perfusion and flushing solution. Vitality, functionality, and metabolic activity of both groups were analyzed. Results: Perfused muscles, in contrast to the ischemically stored ones, showed no loss of vitality and significantly less functionality loss, confirming the superiority of storage under continuous perfusion over ischemic storage. Furthermore, in comparison to a previous study, the results were improved even further by using a modified hydroxyethyl starch solution. Conclusion: The use of EP has major benefits compared to the clinical standard static storage at room temperature. Continuous perfusion not only maintains the oxygen and nutrient supply but also removes toxic metabolites formed due to inadequate storage conditions.

The Role of Plastic Reconstructive Surgery in Surgical Therapy of Soft Tissue Sarcomas

Background: Soft tissue sarcoma (STS) treatment is an interdisciplinary challenge. Along with radio(chemo)therapy, surgery plays the central role in STS treatment. Little is known about the impact of reconstructive surgery on STS, particularly whether reconstructive surgery enhances STS resection success with the usage of flaps. Here, we analyzed the 10-year experience at a university hospital’s Comprehensive Cancer Center, focusing on the role of reconstructive surgery. Methods: We performed a retrospective analysis of STS-patients over 10 years. We investigated patient demographics, diagnosis, surgical management, tissue/function reconstruction, complication rates, resection status, local recurrence and survival. Results: Analysis of 290 patients showed an association between clear surgical margin (R0) resections and higher-grade sarcoma in patients with free flaps. Major complications were lower with primary wound closure than with flaps. Comparison of reconstruction techniques showed no significant differences in complication rates. Wound healing was impaired in STS recurrence. The local recurrence risk was over two times higher with primary wound closure than with flaps. Conclusion: Defect reconstructions in STS are reliable and safe. Plastic surgeons should have a permanent place in interdisciplinary surgical STS treatment, with the full armamentarium of reconstruction methods.

Lipotransfer führt zu Verbesserung von Schluck- und Artikulationsstörungen nach mikrochirurgischer Zungenrekonstruktion – ein Fallbericht

ZusammenfassungNach mikrochirurgischer Zungenrekonstruktion durch freie Lappenplastiken kommt es häufig zu einer Atrophie der Zunge, was zu funktionellen Einschränkungen wie Artikulationsstörungen oder Dysphagie führt. Eine Volumenaugmentation mittels Lipotransfer könnte dieser Problematik entgegenwirken. Wir beschreiben einen Fallbericht über wiederholte Lipotransfers in eine atrophierte rekonstruierte Zunge. Ein 66-jähriger Patient hatte bei Plattenepithelkarzinom der Zunge eine Hemiglossektomie und die anschließende Zungenrekonstruktion mittels freier Radialislappenplastik erhalten. Nach Atrophie der rekonstruierten Zunge führten wir wiederholte Lipotransfer-Sitzungen zur Augmentation des atrophierten Gewebes durch. Insgesamt führten drei Lipotransfer-Sitzungen zu einem zufriedenstellenden Ergebnis. Durch die Augmentation der Zunge konnte eine Verbesserung der ursprünglichen Schluck- und Artikulationsstörungen erzielt werden.Dies ist nach unserem Kenntnisstand der erste Fallbericht über Augmentation eines Lappens in der Mundhöhle mittels Lipotransfer, welches ein nützliches Mittel bei der Zungenrekonstruktion darstellt. Wir empfehlen daher die Volumenaugmentation mittels Lipotransfer als zusätzliches Hilfsmittel zur Verbesserung des funktionellen Status bei der Zungenrekonstruktion.

Comparison of Hydrogels for the Development of Well-Defined 3D Cancer Models of Breast Cancer and Melanoma

Bioprinting offers the opportunity to fabricate precise 3D tumor models to study tumor pathophysiology and progression. However, the choice of the bioink used is important. In this study, cell behavior was studied in three mechanically and biologically different hydrogels (alginate, alginate dialdehyde crosslinked with gelatin (ADA–GEL), and thiol-modified hyaluronan (HA-SH crosslinked with PEGDA)) with cells from breast cancer (MDA-MB-231 and MCF-7) and melanoma (Mel Im and MV3), by analyzing survival, growth, and the amount of metabolically active, living cells via WST-8 labeling. Material characteristics were analyzed by dynamic mechanical analysis. Cell lines revealed significantly increased cell numbers in low-percentage alginate and HA-SH from day 1 to 14, while only Mel Im also revealed an increase in ADA–GEL. MCF-7 showed a preference for 1% alginate. Melanoma cells tended to proliferate better in ADA–GEL and HA-SH than mammary carcinoma cells. In 1% alginate, breast cancer cells showed equally good proliferation compared to melanoma cell lines. A smaller area was colonized in high-percentage alginate-based hydrogels. Moreover, 3% alginate was the stiffest material, and 2.5% ADA–GEL was the softest material. The other hydrogels were in the same range in between. Therefore, cellular responses were not only stiffness-dependent. With 1% alginate and HA-SH, we identified matrices that enable proliferation of all tested tumor cell lines while maintaining expected tumor heterogeneity. By adapting hydrogels, differences could be accentuated. This opens up the possibility of understanding and analyzing tumor heterogeneity by biofabrication.

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