Defect Coverage after Forequarter Amputation—A Systematic Review Assessing Different Surgical Approaches

Autologous fillet flaps are a common reconstructive option for large defects after forequarter amputation (FQA) due to advanced local malignancy or trauma. The inclusion of osseous structures into these has several advantages. This article therefore systematically reviews reconstructive options after FQA, using osteomusculocutaneous fillet flaps, with emphasis on personalized surgical technique and outcome. Additionally, we report on a case with an alternative surgical technique, which included targeted muscle reinnervation (TMR) of the flap. Our literature search was conducted in the PubMed and Cochrane databases. Studies that were identified were thoroughly scrutinized with regard to relevance, resulting in the inclusion of four studies (10 cases). FQA was predominantly a consequence of local malignancy. For vascular supply, the brachial artery was predominantly anastomosed to the subclavian artery and the brachial or cephalic vein to the subclavian or external jugular vein. Furthermore, we report on a case of a large osteosarcoma of the humerus. Extended FQA required the use of the forearm for defect coverage and shoulder contour reconstruction. Moreover, we performed TMR. Follow-up showed a satisfactory result and no phantom limb pain. In case of the need for free flap reconstruction after FQA, this review demonstrates the safety and advantage of osteomusculocutaneous fillet flaps. If the inclusion of the elbow joint into the flap is not possible, we recommend the use of the forearm, as described. Additionally, we advocate for the additional implementation of TMR, as it can be performed quickly and is likely to reduce phantom limb and neuroma pain

Fine tuning of the side-to-side tenorrhaphy: A biomechanical study assessing different side-to-side suture techniques in a porcine tendon model

Recent studies conclude that a new technique for tendon transfers, the side-to-side tenorrhaphy by Friden (FR) provides higher biomechanical stability than the established standard first described by Pulvertaft (PT). The aim of this study was to optimize side-to-side tenorrhaphies. We compared PT and FR tenorrhaphies as well as a potential improvement, termed Woven-Friden tenorrhaphy (WF), with regard to biomechanical stability. Our results demonstrate superior biomechanical stability and lower bulk of FR and, in particular, WF over PT tenorrhaphies. The WF and FR technnique therefore seem to be a notable alternative to the established standard tenorrhaphy as they display lower bulk and higher stability, permitting successful immediate active mobilization after surgery

Mehrfach ungesättigte Fettsäuren, kolorektale Karzinome und Entzündung: Die Wirkung von drei bedeutenden mehrfach ungesättigten Fettsäuren auf die Synthese von Lipidmediatoren der Kolonkarzinom-Zelllinie HT-29 und die Zytokin-Sekretion von mononukleären Zellen des peripheren Blutes

Omega-3 and omega-6 polyunsaturated fatty acids (n-3 and n-6 PUFAs) have been shown to modulate inflammation. N-3 PUFAs predominantly seem to suppress inflammatory processes, while n-6 PUFAs have been shown to act as pro-inflammatory agents. Additionally, n-3 and n-6 PUFAs may have an effect on the growth and progression of colorectal cancer (CRC), a tumor in close relationship with immune cells. PUFA-derived lipid mediators play an important role in mediating these effects. The exact role of n-3 and n-6 PUFAs in inflammation and in CRC, however, remains controversial. To further explore the effect of n-3 and n-6 PUFAs on CRC, in particular with regard to the formation of PUFA-derived lipid mediators, we investigated whether incubation with two n-3 PUFAs (eicosapentaenoic acid, EPA; and docosahexaenoic acid, DHA) and one n-6 PUFA (arachidonic acid, AA) affects the lipid metabolism of human colorectal adenocarcinoma HT-29 cells. Additionally, we explored the effect of PUFAs on immune cell function in general, as well as with regard to the crosstalk between immune and CRC cells. For this, we assessed whether incubation with DHA, EPA, or AA would modulate the secretion of TNF-a, IL-6, or IL-10 by human peripheral blood mononuclear cells (PBMCs), stimulated with lipopolysaccharide (LPS) or conditioned media (CM) of HT-29 cells. Incubation with EPA significantly increased the synthesis of EPA-derived lipid metabolites in HT-29 cells. Incubation of PBMCs with DHA enhanced a pro- inflammatory cytokine profile. Thus, DHA significantly decreased LPS- and CM-induced secretion of IL-10 and increased CM-induced secretion of TNF-α. AA, on the other hand, reduced TNF-α secretion (stimulation with LPS and CM). Analysis of variance revealed that, when compared to incubation with n-3 PUFAs (EPA and DHA), secretion of TNF-α was significantly lower in PBMCs incubated with AA. The observed increase in EPA-derived lipid metabolites may be a mechanism for how EPA exerts its previously described effects on CRC. Our results further demonstrate that the general paradigm of the role of PUFAs in inflammation represents an oversimplification. Similar to other studies, we were able to show that under certain conditions n-3 PUFAs may have pro-inflammatory and n-6 PUFAs anti-inflammatory 1 effects. Moreover, with regard to recent studies on tumor immune therapy, as well as prostaglandin-E2-mediated immune dysfunction and tumor growth, changes in CM- induced cytokine secretion upon incubation with DHA raise the possibility of a beneficial effect of n-3 PUFAs in patients with CRC, through a more aggressive immunological response against tumor cells.Zusammenfassung Mehrere Studien konnten einen Einfluss von mehrfach ungesättigten Omega-3- und Omega-6-Fettsäuren (n-3 und n-6 PUFAs) auf das Immunsystem nachweisen. In diesem Zusammenhang scheinen n-3 PUFAs eine überwiegend antiinflammatorische Wirkung zu haben, während n-6 PUFAs die Immunantwort fördern. Ebenfalls wurde ein möglicher Einfluss dieser Fettsäuren auf das kolorektale Karzinom (CRC) beschrieben, ein Malignom, welches in enger Verbindung mit dem Immunsystem steht. Insbesondere potente Lipidmediatoren, entstanden aus enzymatischer Katalyse von n-3 und n-6 PUFAs, spielen eine wichtige Rolle in diesen beschriebenen Effekten. Der genaue Einfluss von n-3 und n-6 PUFAs auf das Immunsystem und das CRC ist jedoch weiterhin unklar. Ziel der vorliegenden Studie war daher, die Wirkung von n-3 und n-6 PUFAs auf den Lipidstoffwechsel der Kolonkarzinom-Zelllinie HT-29 sowie auf die Immunantwort, insbesondere mit Hinblick auf das CRC, zu untersuchen. In einem ersten Experiment wurde der Einfluss von zwei n-3 PUFAs (Eicosapentaensäure (EPA) und Docosahexaensäure (DHA)) und einer n-6 PUFA (Arachidonsäure (AA)) auf die Synthese von Lipidmediatoren von HT-29 Zellen untersucht. In einem weiteren Versuch wurde der Effekt von EPA, DHA und AA auf die Zytokin-Sekretion (TNF-a, IL-6 und IL- 10) von mononukleären Zellen des peripheren Blutes (PBMCs) untersucht. PBMCs wurden hierfür mit Lipopolysacchariden (LPS) oder konditioniertem Medium von HT-29 Zellen (CM) stimuliert. Die Inkubation von HT-29 Zellen mit EPA erhöhte den Anteil an EPA-basierten Lipidmetaboliten. Die Inkubation von PBMCs mit DHA führte zu einem proinflammatorischen Zytokinprofil: Es zeigte sich eine reduzierte Sekretion von IL-10 nach Stimulation mit LPS und CM sowie eine erhöhte CM-induzierte Sekretion von TNF-α. Im Gegensatz hierzu, reduzierte AA die LPS- und CM-induzierte Sekretion von TNF-α. Die durchgeführte Varianzanalyse bestätigte diesen Trend: Verglichen mit PBMCs, welche mit n-3 PUFAs (DHA und EPA) inkubiert wurden, verringerte AA die LPS- und CM-induzierte Sekretion von TNF-α. Eine Zunahme von EPA-basierten Lipidmetaboliten ist ein wahrscheinlicher Wirkmechanismus, über den EPA seine bisher beschriebenen Effekte auf das CRC ausübt. Die Ergebnisse der Versuche mit PBMCs zeigen, dass das bisherige Paradigma von n-3 und n-6 PUFAs in Hinblick auf die Immunantwort eine Vereinfachung darstellt. Ähnlich wie andere Studien, zeigen die vorliegenden Experimente, dass n-3 PUFAs unter bestimmten Bedingungen proinflammatorische und n-6 PUFAs antiinflammatorische Effekte haben können. Diese Ergebnisse sind insbesondere im Hinblick auf aktuelle Studien zur Immuntherapie bei Malignomen sowie zu Tumorwachstum aufgrund von Prostaglandin-E2-vermittelter Immundysfunktion von Interesse: Der demonstrierte Einfluss von DHA auf die CMinduzierte Immunantwort macht deutlich, dass n-3 PUFAs mögliche antikanzerogene Effekte bei Patienten mit CRC über eine verstärkte Immunantwort ausüben könnten

Analysis of Factors Determining Patient Survival after Receiving Free-Flap Reconstruction at a Single Center—A Retrospective Cohort Study

Background: Microsurgical tissue transfer revolutionized reconstructive surgery after extensive trauma, oncological resections, and severe infections. Complex soft tissue reconstructions are increasingly performed in multimorbid and elderly patients. Therefore, it is crucial to investigate whether these patients benefit from these complex procedures. Objective: To evaluate the outcome for multimorbid patients who underwent microsurgical soft tissue reconstruction and to identify potential risk factors that may increase mortality. Methods: This single-center study retrospectively analyzed prospectively collected data of patients receiving free gracilis (GM) or latissimus dorsi muscle (LDM) flap reconstruction between September 2017 and December 2021. Cases were divided into two groups (dead vs. alive), depending on patient survival. Patient demographics, comorbidities and medication, perioperative details, free flap outcome, as well as microcirculation were determined. Results: A total of 151 flaps (LDM, n = 67; GM, n = 84) performed in 147 patients with a mean age of 61.15 ± 17.5 (range 19–94) years were included. A total of 33 patients (22.45%) passed away during the study period. Deceased patients were significantly older (Alive: 58.28 ± 17.91 vs. Dead: 71.39 ± 11.13; p = 0.001), were hospitalized significantly longer (Alive: 29.66 ± 26.97 vs. Dead: 36.88 ± 15.04 days; p = 0.046) and suffered from cardiovascular (Alive: 36.40% vs. Dead: 66.70%; p = 0.002) and metabolic diseases (Alive: 33.90% vs. Dead: 54.50%; p = 0.031) more frequently, which corresponded to a significantly higher ASA Score (p = 0.004). Revision rates (Alive: 11.00% vs. Dead: 18.20%; p = 0.371) and flap loss (Alive: 3.39% vs. Dead: 12.12%; p = 0.069) were higher in patients that died by the end of the study period. Conclusions: Free flap transfer is safe and effective, even in multimorbid patients. However, patient age, comorbidities, preoperative ASA status, and medication significantly impact postoperative patient survival in the short- and mid-term and must, therefore, be taken into account in preoperative decision-making and informed consent

Defect Coverage after Forequarter Amputation—A Systematic Review Assessing Different Surgical Approaches

Autologous fillet flaps are a common reconstructive option for large defects after forequarter amputation (FQA) due to advanced local malignancy or trauma. The inclusion of osseous structures into these has several advantages. This article therefore systematically reviews reconstructive options after FQA, using osteomusculocutaneous fillet flaps, with emphasis on personalized surgical technique and outcome. Additionally, we report on a case with an alternative surgical technique, which included targeted muscle reinnervation (TMR) of the flap. Our literature search was conducted in the PubMed and Cochrane databases. Studies that were identified were thoroughly scrutinized with regard to relevance, resulting in the inclusion of four studies (10 cases). FQA was predominantly a consequence of local malignancy. For vascular supply, the brachial artery was predominantly anastomosed to the subclavian artery and the brachial or cephalic vein to the subclavian or external jugular vein. Furthermore, we report on a case of a large osteosarcoma of the humerus. Extended FQA required the use of the forearm for defect coverage and shoulder contour reconstruction. Moreover, we performed TMR. Follow-up showed a satisfactory result and no phantom limb pain. In case of the need for free flap reconstruction after FQA, this review demonstrates the safety and advantage of osteomusculocutaneous fillet flaps. If the inclusion of the elbow joint into the flap is not possible, we recommend the use of the forearm, as described. Additionally, we advocate for the additional implementation of TMR, as it can be performed quickly and is likely to reduce phantom limb and neuroma pain

Finding the Optimal Surgical Incision Pattern—A Biomechanical Study

The closure of wounds and subsequent optimal wound healing is essential to any successful surgical intervention. Especially on parts of the body with limited possibilities for local reconstruction, optimal distribution of load is essential. The aim of the present study was therefore to examine three different incision patterns, conventional straight, Lazy-S and Zigzag, with regard to their biomechanical stability and mode of failure on a porcine skin model. Our results demonstrate the superior biomechanical stability of Lazy-S and Zigzag incision patterns with perpendicular suture placement. This holds true, in particular, for Zigzag incisions, which showed the highest values for all parameters assessed. Moreover, the observed superior stability of Lazy-S and Zigzag incision patterns was diminished when sutures were placed in tensile direction. The conventional straight incision represents the standard access for a large number of surgical procedures. However, we were able to demonstrate the superior biomechanical stability of alternative incision patterns, in particular the Zigzag incision. This is most likely caused by an improved distribution of tensile force across the wound due to the perpendicular placement of sutures. Moreover, this technique offers additional advantages, such as a better overview of the operated area as well as several cosmetic improvements. We therefore advocate that the surgeon should consider the use of a Zigzag incision over a conventional straight incision pattern

Biomechanical Test Setup for the Investigation of Forehead Suture Techniques

Wound healing can be delayed if the biomechanical stability of the wound closure is inadequate. Therefore, it is necessary to investigate different suturing techniques for their biomechanical stability. In this study, suturing techniques suitable for the forehead area were investigated. For this application, a special test setup was developed to simulate the curvature of the forehead and the corresponding physiological configuration. The average forehead curvature is 62.24 ± 4.11 mm in radius. To simulate this curvature, the skin specimens are subjected to tensile stress over the spherical surface using a standard uniaxial testing machine. For the evaluation, an automated evaluation tool for MATLAB was also developed. Three different suturing techniques (Straight, Lazy-S, Zigzag) were investigated and tested for their biomechanical stability. Of the three suturing techniques, the Zigzag suture proved to be the most stable with the highest stiffness of 44.23 ± 8.18 % and the highest final failure of 32.60 ± 4.95 % (relative to the control sample without incision). The study has shown that the test setup can be used to investigate different forehead suture techniques