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Introduction: Microsurgery courses, taught external to surgical training programs, are essential for acquiring the high level of technical skill required for clinical proficiency.
Methods: The Frankfurt microsurgery course is a 5-day, intensive course that teaches arterial and venous anastomosis using end-to-end, end-to-side, one-way-up, continuous-suture, and vessel graft techniques. During the course, the instructor records the level of skill (in-course data) achieved by each trainee by assessing anastomosis completion and patency. Demographic information is also collected. Post-course trainees are invited to complete an online survey (post-course data) to get their opinions of the courses’ effectiveness.
Results: The in-course “skill achievement” and post-course “course effectiveness” data are presented below. In-course data: 94.8 and 59.9% of participants completed patent end-to-end arterial and venous anastomoses, respectively, while 85.4% performed a patent end-to-side anastomosis. 96.1 and 57.1% of participants who attempted arterial and venous anastomoses using the one-way-up technique were successful, as were 90.9% of those attempting continuous-suture technique. Patent venous grafts were performed by 54.7% of participants.
Post-course data: All respondents indicated significant improvement of their microsurgical skills after taking the course. 66.7% of respondents considered the full-time presence of the instructor to be the most valuable aspect of the course. All respondents would highly recommend the course to colleagues.
Conclusion: The microcourse significantly increased trainees’ clinical microsurgery skills, confidence, and the number of clinical cases they perform. Of all the anastomosis techniques taught, venous anastomosis and grafting were the most difficult to learn. The presence of a full-time experienced instructor was most important.
Introduction. Cancellous bone is frequently used for filling bone defects in a clinical setting. It provides favourable conditions for regenerative cells such as MSC and early EPC. The combination of MSC and EPC results in superior bone healing in experimental bone healing models. Materials and Methods. We investigated the influence of osteogenic culture conditions on the endothelial properties of early EPC and the osteogenic properties of MSC when cocultured on cancellous bone. Additionally, cell adhesion, metabolic activity, and differentiation were assessed 2, 6, and 10 days after seeding.
Results. The number of adhering EPC and MSC decreased over time; however the cells remained metabolically active over the 10-day measurement period. In spite of a decline of lineage specific markers, cells maintained their differentiation to a reduced level. Osteogenic stimulation of EPC caused a decline but not abolishment of endothelial characteristics and did not induce osteogenic gene expression. Osteogenic stimulation of MSC significantly increased their metabolic activity whereas collagen-1α and alkaline phosphatase gene expressions declined. When cocultured with EPC, MSC’s collagen-1α gene expression increased significantly. Conclusion. EPC and MSC can be cocultured in vitro on cancellous bone under osteogenic conditions, and coculturing EPC with MSC stabilizes the latter’s collagen-1α gene expression.
Background: Extremity fracture is frequently seen in multiple traumatized patients. Local post-traumatic inflammatory reactions as well as local and systemic interactions have been described in previous studies. However, trauma severity and its impact on the local immunologic reaction remains unclear. Therefore, fracture-associated local inflammation was investigated in a porcine model of isolated and combined trauma to gain information about the early inflammatory stages.
Material and Methods: Polytrauma (PT) consisted of lung contusion, liver laceration, femur fracture, and controlled hemorrhage. Monotrauma (MT) consisted of femur fracture only. The fracture was operatively stabilized and animals were monitored under ICU-standard for 72 h. Blood, fracture hematoma (FH) as well as muscle samples were collected throughout the experimental period. Levels of local and systemic pro- and anti-inflammatory as well as angiogenetic cytokines were measured by ELISA.
Results: Both groups showed a significant decrease in pro-inflammatory IL-6 in FH over time. However, concentrations in MT were significantly higher than in PT. The IL-8 concentrations initially decreased in FH, but recovered by the end of the observation period. These dynamics were only statistically significant in MT. Furthermore, concentrations measured in muscle tissue showed inverse kinetics compared to those in FH. The IL-10 did not present statistical resilient dynamics over time, although a slight increase in FH was seen by the end of the observation time in the MT group.
Conclusions: Time-dependent dynamics of the local inflammatory response were observed. Trauma severity showed a significant impact, with lower values in pro- as well as angiogenetic mediators. Fracture repair could be altered by these trauma-related changes of the local immunologic milieu, which might serve as a possible explanation for the higher rates of delayed or non-union bone repair in polytraumatised patients.
Introduction: Epoxyeicosatrienoic acids (EETs) are able to enhance angiogenesis and regulate inflammation that is especially important in wound healing under ischemic conditions. Thus, we evaluated the effect of local EET application on ischemic wounds in mice.
Methods: Ischemia was induced by cautherization of two of the three supplying vessels to the mouse ear. Wounding was performed on the ear three days later. Wounds were treated either with 11,12 or 14,15 EET and compared to untreated control and normal wounds. Epithelialization was measured every second day. VEGF, TNF-α, TGF-β, matrix metalloproteinases (MMP), tissue inhibitors of metalloproteinases (TIMP), Ki67, and SDF-1α were evaluated immunohistochemically in wounds on day 3, 6, and 9.
Results: Ischemia delayed wound closure (12.8 days ± 1.9 standard deviation (SD) for ischemia and 8.0 days ± 0.94 SD for control). 11,12 and14,15 EET application ameliorated deteriorated wound healing on ischemic ears (7.6 ± 1.3 SD for 11,12 EET and 9.2 ± 1.4 SD for 14,15 EET). Ischemia did not change VEGF, TNF-α, TGF-β, SDF-1α, TIMP, MMP7 or MMP9 level significantly compared to control. Local application of 11,12 as well as 14,15 EET induced a significant elevation of VEGF, TGF-β, and SDF-1α expression as well as proliferation during the whole phase of wound healing compared to control and ischemia alone.
Conclusion: In summary, EET improve impaired wound healing caused by ischemia as they enhance neovascularization and alter inflammatory response in wounds. Thus elevating lipid mediator level as 11,12 and 14,15 EET in wounds might be a successful strategy for amelioration of deranged wound healing under ischemia.
Delayed wound repair in sepsis is associated with reduced local pro-inflammatory cytokine expression
(2013)
Sepsis is one of the main causes for morbidity and mortality in hospitalized patients. Moreover, sepsis associated complications involving impaired wound healing are common. Septic patients often require surgical interventions that in-turn may lead to further complications caused by impaired wound healing. We established a mouse model to the study delayed wound healing during sepsis distant to the septic focus point. For this reason cecal ligation and puncture (CLP) was combined with the creation of a superficial wound on the mouse ear. Control animals received the same procedure without CPL. Epithelialization was measured every second day by direct microscopic visualization up to complete closure of the wound. As interplay of TNF-α, TGF-β, matrix metalloproteinases (MMP), and tissue inhibitors of metalloproteinases (TIMP) is important in wound healing in general, TNF-α, TGF-β, MMP7, and TIMP1 were assessed immunohistochemical in samples of wounded ears harvested on days 2, 6, 10 and 16 after wounding. After induction of sepsis, animals showed a significant delay in wound epithelialization from day 2 to 12 compared to control animals. Complete wound healing was attained after mean 12.2± standard deviation (SD) 3.0 days in septic animals compared to 8.7± SD 1.7 days in the control group. Septic animals showed a significant reduction in local pro-inflammatory cytokine level of TNF-α on day 2 and day 6 as well as a reduced expression of TGF-β on day 2 in wounds. A significant lower expression of MMP7 as well as TIMP1 was also observed on day 2 after wounding. The induction of sepsis impairs wound healing distant to the septic focus point. We could demonstrate that expression of important cytokines for wound repair is deregulated after induction of sepsis. Thus restoring normal cytokine response locally in wounds could be a good strategy to enhance wound repair in sepsis.
Background: Polytraumatized patients undergo a strong immunological stress upon insult. Phagocytes (granulocytes and monocytes) play a substantial role in immunological defense against bacteria, fungi and yeast, and in the clearance of cellular debris after tissue injury. We have reported a reduced monocytes phagocytic activity early after porcine polytrauma before. However, it is unknown if both phagocyte types undergo those functional alterations, and if there is a pathogen-specific phagocytic behavior. We characterized the phagocytic activity and capacity of granulocytes and monocytes after polytrauma.
Methods: Eight pigs (Sus scrofa) underwent polytrauma consisting of lung contusion, liver laceration, tibial fracture and hemorrhagic shock with fluid resuscitation and fracture fixation with external fixator. Intensive care treatment including mechanical ventilation for 72 h followed. Phagocytic activity and capacity were investigated using an in vitro ex vivo whole blood stimulation phagocytosis assays before trauma, after surgery, 24, 48, and 72 h after trauma. Blood samples were stimulated with Phorbol-12-myristate-13-acetate and incubated with FITC-labeled E. coli, S. aureus or S. cerevisiae for phagocytosis assessment by flow cytometry.
Results: Early polytrauma-induced significant increase of granulocytes and monocytes declined to baseline values within 24 h. Percentage of E. coli-phagocytizing granulocytes significantly decreased after polytrauma and during further intensive care treatment, while their capacity significantly increased. Interestingly, both granulocytic phagocytic activity and capacity of S. aureus significantly decreased after trauma, although a recovery was observed after 24 h and yet was followed by another decrease. The percentage of S. cerevisiae-phagocytizing granulocytes significantly increased after 24 h, while their impaired capacity after surgery and 72 h later was detected. Monocytic E. coli-phagocytizing percentage did not change, while their capacity increased after 24–72 h. After a significant decrease in S. aureus-phagocytizing monocytes after surgery, a significant increase after 24 and 48 h was observed without capacity alterations. No significant changes in S. cerevisiae-phagocytizing monocytes occurred, but their capacity dropped 48 and 72 h.
Conclusion: Phagocytic activity and capacity of granulocytes and monocytes follow a different pattern and significantly change within 72 h after polytrauma. Both phagocytic activity and capacity show significantly different alterations depending on the pathogen strain, thus potentially indicating at certain and possibly more relevant infection causes after polytrauma.
Introduction: In an emergency department, the majority of pediatric trauma patients present because of minor injuries. The aim of this study was to evaluate temporal changes in age-related injury pattern, trauma mechanism, and surgeries in pediatric patients. Methods: This retrospective study included patients < 18 years of age following trauma from 01/2009 to 12/2018 at a level I trauma center. They were divided into two groups: group A (A: 01/2009 to 12/2013) and group B (B: 01/2014 to 12/2018). Injury mechanism, injury pattern, and surgeries were analyzed. As major injuries fractures, dislocations, and organ injuries and as minor injuries contusions and superficial wounds were defined. Results: 23,582 patients were included (58% male, median age 8.2 years). There was a slight increase in patients comparing A (n = 11,557) and B (n = 12,025) with no difference concerning demographic characteristics. Significant more patients (A: 1.9%; B: 2.4%) were admitted to resuscitation room, though the number of multiple injured patients was not significantly different. In A (25.5%), major injuries occurred significantly less frequently than in B (27.0%), minor injuries occurred equally. Extremity fractures were significantly more frequent in B (21.5%) than in A (20.2%), peaking at 8–12 years. Most trauma mechanisms of both groups were constant, with a rising of sport injuries at 8–12 years. Conclusion: Although number of patients increases only slightly over a decade, there was a clear increase in major injuries, particularly extremity fractures, peaking at 8–12 years. At this age also sport accidents significantly increased. At least, admittance to resuscitation room rose but without an increase of multiple injured patients.
Purpose: Despite the high number of patients with phalangeal fractures, evidence-based recommendations for the treatment of specific phalangeal fractures could not be concluded from the literature. The purpose of the present study was to assess current epidemiological data, classification of the fracture type, and mode of treatment.
Methods: This study presents a retrospective review of 261 patients with 283 phalangeal fractures ≥ 18 years of age who were treated in our level I trauma centre between 2017 and 2018. The data were obtained by the analysis of the institution’s database, and radiological examinations.
Results: The average age of the patients was 40.4 years (range 18–98). The ratio of male to female patients was 2.7:1. The two most typical injury mechanisms were crush injuries (33%) and falls (23%). Most phalangeal fractures occurred in the distal phalanx (P3 43%). The 4th ray (D4 29%) was most frequently affected. The P3 tuft fractures, and the middle phalanx (P2) base fractures each accounted for 25% of fracture types. A total of 74% of fractures were treated conservatively, and 26% required surgery, with Kirschner wire(s) (37%) as the preferred surgical treatment. The decision for surgical treatment correlated with the degree of angular and/or rotational deformity, intraarticular step, and sub-/luxation of specific phalangeal fractures, but not with age and gender.
Conclusions: Our findings demonstrated the popularity of conservative treatment of phalangeal fractures, while surgery was only required in properly selected cases. The correct definition of precise fracture pattern in addition to topography is essential to facilitate treatment decision-making.
Background: Surgical complications are associated with a significant burden to patients and hospitals and are increasingly discussed in recent literature. This cohort study reviewed surgery-related complications in a Level I trauma center. The effect of a complication avoidance care bundle on the rate of surgical complications was analyzed. Methods: All complications (surgical and nonsurgical) that occur in our trauma department are prospectively captured using a standardized documentation form and are discussed and analyzed in a weekly trauma Morbidity and Mortality (M&M) conference. Surgical complication rates are calculated using the annual surgical procedure numbers. Based on discussions in the M&M conference, a complication avoidance care bundle consisting of five measures was established: (1) Improving team situational awareness; (2) reducing operating room traffic by staff members and limiting door-opening events; (3) preoperative screening for infectious foci; (4) adapted preoperative antibiotic prophylaxis in anatomic regions with a high risk of infectious complications; and (5) use of iodine-impregnated adhesive drape. Results: The number of surgical procedures steadily increased over the study years, from 3587 in 2015 to 3962 in 2019 (an increase of 10.5%). Within this 5-year study period, the overall rate of surgical complications was 0.8%. Surgical site infections were the most frequently found complications (n = 40, 24.8% of all surgical complications), followed by screw malposition (n = 20, 12.4%), postoperative dislocations of arthroplasties (n = 18, 11.2%), and suboptimal fracture reduction (n = 18, 11.2%). Following implementation of the complication avoidance care bundle, the overall rate of surgical complications significantly decreased, from 1.14% in the year 2016 to 0.56% in the study year 2019, which represents a reduction of 51% within a 3-year time period. Conclusions: A multimodal strategy targeted at reducing the surgical complication rate can be successfully established based on a transparent discussion of adverse surgical outcomes. The combination of the different preventive measures was associated with reducing the overall complication rate by half within a 3-year time period.
In Bone Tissue Engineering (BTE), autologous bone-regenerative cells are combined with a scaffold for large bone defect treatment (LBDT). Microporous, polylactic acid (PLA) scaffolds showed good healing results in small animals. However, transfer to large animal models is not easily achieved simply by upscaling the design. Increasing diffusion distances have a negative impact on cell survival and nutrition supply, leading to cell death and ultimately implant failure. Here, a novel scaffold architecture was designed to meet all requirements for an advanced bone substitute. Biofunctional, porous subunits in a load-bearing, compression-resistant frame structure characterize this approach. An open, macro- and microporous internal architecture (100 µm–2 mm pores) optimizes conditions for oxygen and nutrient supply to the implant’s inner areas by diffusion. A prototype was 3D-printed applying Fused Filament Fabrication using PLA. After incubation with Saos-2 (Sarcoma osteogenic) cells for 14 days, cell morphology, cell distribution, cell survival (fluorescence microscopy and LDH-based cytotoxicity assay), metabolic activity (MTT test), and osteogenic gene expression were determined. The adherent cells showed colonization properties, proliferation potential, and osteogenic differentiation. The innovative design, with its porous structure, is a promising matrix for cell settlement and proliferation. The modular design allows easy upscaling and offers a solution for LBDT.