Individualized Wound Closure—Mechanical Properties of Suture Materials

Wound closure is a key element of any procedure, especially aesthetic and reconstructive plastic surgery. Therefore, over the last decades, several devices have been developed in order to assist surgeons in achieving better results while saving valuable time. In this work, we give a concise review of the literature and present a biomechanical study of different suturing materials under mechanical load mimicking handling in the operating theatre. Nine different suture products, all of the same USP size (4-0), were subjected to a standardized crushing load by means of a needle holder. All materials were subjected to 0, 1, 3 and 5 crushing load cycles, respectively. The linear tensile strength was measured by means of a universal testing device. Attenuation of tensile strength was evaluated between materials and between crush cycles. In the pooled analysis, the linear tensile strength of the suture materials deteriorated significantly with every cycle (p < 0.0001). The suture materials displayed different initial tensile strengths (in descending order: polyglecaprone, polyglactin, polydioxanone, polyamid, polypropylene). In comparison, materials performed variably in terms of resistance to crush loading. The findings were statistically significant. The reconstructive surgeon has to be flexible and tailor wound closure techniques and materials to the individual patient, procedure and tissue demands; therefore, profound knowledge of the physical properties of the suture strands used is of paramount importance. The crushing load on suture materials during surgery can be detrimental for initial and long-term wound repair strength. As well as the standard wound closure methods (sutures, staples and adhesive strips), there are promising novel devices

Polytetrafluoroethylene (PTFE) suture vs fiberwire and polypropylene in flexor tendon repair

Background!#!In this study, we evaluate the value of novel suture material based on monofilamentous-extruded polyfluoroethylene (PTFE) compared to polypropylene (PPL) and Fiberwire (FW).!##!Materials and methods!#!60 flexor tendons were harvested from fresh cadaveric upper extremities. 4-0 sutures strands were used in the PPL, FW and PTFE group. Knotting properties and mechanical characteristics of the suture materials were evaluated. A 4-strand locked cruciate (Adelaide) or a 6-strand (M-Tang) suture technique was applied as core sutures for a tendon repair. Two-way ANOVA tests were performed with the Bonferroni correction.!##!Results!#!Stable knotting was achieved with 5 throws with the PPL material, 7 throws for FW and 9 throws for PTFE. In the PPL group, linear tensile strength was 45.92 ± 12.53 N, in the FW group 80.11 ± 18.34 N and in the PTFE group 76.16 ± 29.10 N. FW and PTFE are significantly stronger than PPL but show no significant difference among each other. Similar results were obtained in the subgroup comparisons for different repair techniques. The Adelaide and the M-Tang knotting technique showed no significant difference.!##!Conclusion!#!Fiberwire showed superior handling and knotting properties in comparison to PTFE. However, PTFE allows easier approximation of the stumps. In both, M-Tang and Adelaide repairs, PTFE was equal to FW in terms of repair strength. Both PTFE and FW provide for a robust tendon repair so that early active motion regimens for rehabilitation can be applied

Prefabricated flaps and neoangiogenesis initiated via venous grafts in arteriovenous loops

New developments in regenerative medicine are bound to revolutionize the way we approach loss of function and form in human organisms. Especially in the field of reconstructive plastic surgery new biotechnologies find their way from bench to bed. Biofabrication is an evolving field that aims to combine natural biologic processes with bioartificial constructs with the scope of reconstituting tissue without having to rely on autotransplantation. In this brief review we present the concepts of intrinsic vs. extrinsic neovascularization and we discuss the use of neovascularization in three dimensional matrices. In a clinical context matrix flaps for application in reconstructive surgery can be fabricated this way

Can systemically administered antibiotics be detected in wound tissues and surfaces under negative pressure wound therapy?

In this study, we evaluated a new aspect of negative pressure wound therapy (NPWT) as an analytical tool for pharmacokinetic studies. Twenty-one patients with soft tissue defects scheduled to receive NPWT were included in this study. Concomitant to NPWT, all patients received intravenous moxifloxacin (MX). At different time intervals, blood plasma levels of MX were sampled and compared with synchronous concentrations of MX in the exudate obtained from the NPWT drainage system. Serial measurements were performed upon initiation of the therapy as well as in the steady state (after 5 days). At steady state, wound tissue was obtained intraoperatively. High-performance liquid-chromatography (HPLC) was used for analysis. At 1 hour post-administration, the exudate/plasma levels (mg/L) were 1.92/3.07; at 12 hours, 0.80/1.14; at 24 hours, 0.26/0.43; and at 120 hours (steady state), 0.42/0.47. There was a correlation between exudate and plasma levels reaching approximately 0.75. Until now, methods for pharmacokinetic studies concerning interstitial fluid are difficult to apply in the clinical context. The presented method showed limitations, but we believe that, after methodological improvements, measurements of substances in the interstitial fluid by means of NPWT are feasible

Can systemically administered antibiotics be detected in wound tissues and surfaces under negative pressure wound therapy?

In this study, we evaluated a new aspect of negative pressure wound therapy (NPWT) as an analytical tool for pharmacokinetic studies. Twenty-one patients with soft tissue defects scheduled to receive NPWT were included in this study. Concomitant to NPWT, all patients received intravenous moxifloxacin (MX). At different time intervals, blood plasma levels of MX were sampled and compared with synchronous concentrations of MX in the exudate obtained from the NPWT drainage system. Serial measurements were performed upon initiation of the therapy as well as in the steady state (after 5 days). At steady state, wound tissue was obtained intraoperatively. High-performance liquid-chromatography (HPLC) was used for analysis. At 1 hour post-administration, the exudate/plasma levels (mg/L) were 1.92/3.07; at 12 hours, 0.80/1.14; at 24 hours, 0.26/0.43; and at 120 hours (steady state), 0.42/0.47. There was a correlation between exudate and plasma levels reaching approximately 0.75. Until now, methods for pharmacokinetic studies concerning interstitial fluid are difficult to apply in the clinical context. The presented method showed limitations, but we believe that, after methodological improvements, measurements of substances in the interstitial fluid by means of NPWT are feasible

Synchronous atypical fibroxanthoma and Bowen’s disease of the head and neck in an otherwise normal patient – a case report and review of literature [Simultanes Auftreten eines atypischen Fibroxanthoms und Plattenepithelkarzinoms im Kopf-Hals-Bereich – Fallbericht und Literaturübersicht]

[english] Although both atypical fibroxanthoma and squamous cell carcinoma arise on top of sun-damaged skin of the elderly, there is no evidence in literature reporting a synchronous presentation of primary lesions of both malignancies in the head and neck regions. We report a case of synchronous atypical fibroxanthoma and squamous cell carcinoma in situ (Bowen’s disease) of the head and neck in an otherwise normal old Caucasian male patient. We reviewed the literature for cases of head and neck atypical fibroxanthoma in association with other skin malignancies with an overview over the risk factors and modalities of treatment. We would like to raise the awareness for the concept of multiple synchronous primary malignant lesions and the importance to anticipate and differentiate between different pathologies in order to provide adequate investigations and treatment for the patient. <br>[german] Obwohl sowohl das atypische Fibroxanthom der Haut als auch das Plattenepithelkarzinom bei sonnengeschädigter Haut älterer Menschen gehäuft vorkommen, gibt es in der Literatur keine Beschreibung eines simultanen Auftretens beider Malignome als Primärläsionen im Kopf-Hals-Bereich. Aus diesem Grund möchten wir über einen Fall berichten, bei dem sowohl ein atypisches Fibroxanthom als auch ein Morbus Bowen (als in situ Variante des Plattenepithelkarzinoms) im Kopf-Hals-Bereich eines sonst gesunden 74-jährigen männlichen Patienten aufgetreten ist. Auf Grundlage der bestehenden Publikationen von Fällen mit atypischen Fibroxanthomen in Assoziation mit anderen Hautmalignomen, verglichen wir diese mit dem vorliegenden Fall, insbesondere in Hinblick auf die Risikofaktoren und das empfohlene Behandlungsregime. Ein simultanes Auftreten von mehreren primären Hauttumoren verschiedener Entität ist in einigen Fällen möglich und sollte daher insbesondere bei älteren Menschen deutlich häufiger in die Beurteilung und Diagnosestellung mit eingeschlossen werden. Ein Hauptaugenmerk sollte hierbei insbesondere auf die Differenzierung dieser verschiedenartigen Pathologien zu liegen kommen, um so eine inadäquate Therapie zu vermeiden

Vital staining of blood vessels and bile ducts with carboxyfluorescein diacetate succinimidyl ester: a novel tool for isolation of cholangiocytes

Background and aim: Current methods for visualization of the blood vasculature, biliary tree and for isolation of vital cholangiocytes are afflicted with a plethora of technical difficulties, especially in mice. In this project, we propose a novel, reliable and straightforward alternative technique for histological demonstration of blood- and biliary systems and derivation of vital cholangiocytes. Methods: Intravital retrograde perfusion of bile ducts was performed in twenty wild type mice. Liver and gallbladder were exposed by median laparotomy. Using a venous catheter, the gallbladder was cannulated, a few millimeters of the liver edge were cropped to allow free outflow of the perfusate, and carboxyfluorescein diacetate succinimidyl ester (CFDA-SE) solution was retrogradely infused. Thereafter, formaldehyde solution was either injected through the same catheter, or the liver was immediately dissociated into a single-cell suspension for FACS-analysis. Intravital perfusion of the vascular system was performed in ten Lewis rats by direct intra-arterial injection of CFDA-SE into the abdominal aorta. The specificity and sensitivity of CFDA-SE labeling was controlled using Indian ink or cytokeratin 19 immunohistochemistry respectively. Results: Upon histomorphological analysis of cryoand paraffin sections, strong fluorescence was noted in large and small bile ducts throughout the entire liver and in the vascular system after infusion of the CFDA-SE solution. In preliminary FACS-experiments, we succeeded in separating cholangiocytes based on combined CFDA-SE-staining and cell size. Conclusions: Visualization of liver architecture and the isolation of cholangiocytes is feasible using a fast and cost-effective method of retrograde perfusion and vital fluorescent labeling of mouse bile duct epithelium and vascular endothelium with CFDA-SE