Tension is a principal force experienced by skin and serves a critical role in growth and development. Optimal tension application regimens may be an important component for skin tissue engineering ...and dermatogenesis. In this study, we designed and tested a novel servo-controlled skin-stretching device to apply predetermined tension and waveforms in mice. The effects of static and cyclical stretching forces were compared in 48 mice by measuring epidermal proliferation, angiogenesis, cutaneous perfusion, and principal growth factors using immunohistochemistry, real-time reverse transcriptase-polymerase chain reaction, and hyperspectral imaging. All stretched samples had upregulated epidermal proliferation and angiogenesis. Real-time reverse transcriptase-polymerase chain reaction of epidermal growth factor, transforming growth factor beta1, and nerve growth factor demonstrated greater expression in cyclically stretched skin when compared to static stretch. Hypoxia-induced factor 1alpha was significantly upregulated in cyclically stretched skin, but poststretch analysis demonstrated well-oxygenated tissue, collectively suggesting the presence of transient hypoxia. Waveform-specific mechanical loads may accelerate tissue growth by mechanotransduction and as a result of repeated cycles of temporary hypoxia. Further analysis of mechanotransduction signaling pathways may provide additional insight to improve skin tissue engineering methods and optimize our device.
Clinical applications of skin substitutes Nyame, Theodore T; Chiang, H Abraham; Orgill, Dennis P
The Surgical clinics of North America,
08/2014, Letnik:
94, Številka:
4
Journal Article
Recenzirano
A unique understanding of the components of mammalian skin has led to the development of numerous skin substitutes. These skin substitutes attempt to compensate for functional and physiologic ...deficits present in damaged tissue. Skin substitutes, when appropriately applied in optimized settings, offer a promising solution to difficult wound management. The body of literature on skin substitutes increases as the understanding of tissue engineering and molecular biology expands. Given the high cost of these products, future randomized large prospective studies are needed to guide the clinical applications of skin substitutes.
Abstract Background Prophylactic anticoagulation is routinely used in the inpatient setting; however, the risk of VTE remains elevated after discharge. Extensive evidence and clinical guidelines ...suggest post-discharge VTE prophylaxis is critical in at-risk populations but it remains severely underutilized in practice. Study Design We performed a single institution retrospective, non-randomized, pre- and post-intervention analysis of a systematic post-discharge pharmacological prophylaxis program against the primary outcome, post-discharge symptomatic VTE. An institutional American College of Surgeons NSQIP dataset was employed to identify patients and outcomes. Patients undergoing major abdominal surgery for malignancy or IBD were eligible for the post-discharge VTE prevention program. Results Among 1,043 patients who underwent abdominal surgery for malignancy or IBD, 800 (77%) were in the pre-intervention cohort and 243 (23%) patients were in the post-intervention cohort. Rates of inpatient VTE did not significantly differ between cohorts (0.7%, n=6 pre-intervention vs. 1.7%, n=4 post-intervention, P =0.25). However, compared to the pre-intervention cohort, patients in the post-intervention cohort demonstrated a significantly lower post-discharge VTE rate (2.5%, n=20 pre-intervention vs. 0.0%, n=0 post-intervention, P <0.01). Conclusions A systematic post-discharge VTE prophylaxis program including provider education, local guideline adaptation, bedside medication delivery, and education for at-risk patients was associated with significantly fewer post-discharge VTE events.
The objective of this experimental animal study was to compare the surgical precision of a flexible CO2 laser fiber with that of monopolar electrosurgery in porcine myometrium. The subjects were 6 ...live adult non-pregnant female pigs. Linear injury to the uterine horns was created using a flexible CO2 laser fiber at 5W, 10W, and 15W and with monopolar electrosurgery at 10W, 20W, 30W, and 40W in both cut and coagulation modes. Hysterectomy was then performed in the live animals. Cross-sections of the tissue were processed and stained using Masson trichrome to differentiate damaged from undamaged myometrium. Measurement means were compared using analysis of variance with Tukey honest significant difference correction; p <.05 indicated significance. Incision width of the laser at 5W and 10W was significantly less than both monopolar coagulation at all power settings and monopolar cut at 30W and 40W (all p <.01), at 5W was also significantly less than monopolar cut at 10W (p = .03), and at 15W was significantly less than monopolar coagulation at 40W (p = .001). Incision depth of the laser at 5W was significantly less than monopolar coagulation at 40W and laser at 15W (both p = .01), at 15W was significantly greater than monopolar coagulation at 10W and monopolar cut at 10, 20, and 30W (p ≤.01), and increased proportional to power for all 3 energy types. Collateral thermal damage width at all laser power settings was significantly less than at all monopolar coagulation power settings (p ≤.04) with the exception of the laser at 15W compared with monopolar coagulation at 10W (p = .30), and at all laser power settings was significantly less than at all monopolar coagulation power settings (p <.001). Collateral thermal damage depth of the laser at 5W and 10W was significantly less than monopolar cut at 30W (p ≤.002) and increased proportional to power in monopolar coagulation mode but remained constant with the laser. Incising efficiency of the laser at 5W was significantly greater than monopolar coagulation at 10W (p = .04), at 10W was significantly greater than at all monopolar power settings (p ≤.007) except cut at 40W (p = .29), and at 15W was significantly greater than that of every other energy type and power setting tested (p ≤.04). These findings support the hypothesis that CO2 laser energy delivered via a flexible fiber system would exhibit greater surgical precision than monopolar electrosurgery, in both cut and coagulation modes, as defined by 3 parameters: incising efficiency, changes in incision depth compared with width as power increases, and variability in the resulting incision measurements. Because increased thermal damage has been associated with delayed tissue necrosis and adhesion formation, these findings prompt the design of a comparative survival animal study to assess additional clinically relevant parameters.
Diffusion and Perfusion: The Keys to Fat Grafting Khouri, Roger K; Khouri, Raoul-Emil R; Lujan-Hernandez, Jorge R ...
Plastic and reconstructive surgery. Global open,
2014-September, Letnik:
2, Številka:
9
Journal Article
Recenzirano
Odprti dostop
BACKGROUND:Fat grafting is now widely used in plastic surgery. Long-term graft retention can be unpredictable. Fat grafts must obtain oxygen via diffusion until neovascularization occurs, so oxygen ...delivery may be the overarching variable in graft retention.
METHODS:We studied the peer-reviewed literature to determine which aspects of a fat graft and the microenvironment surrounding a fat graft affect oxygen delivery and created 3 models relating distinct variables to oxygen delivery and graft retention.
RESULTS:Our models confirm that thin microribbons of fat maximize oxygen transport when injected into a large, compliant, well-vascularized recipient site. The “Microribbon Model” predicts that, in a typical human, fat injections larger than 0.16 cm in radius will have a region of central necrosis. Our “Fluid Accommodation Model” predicts that once grafted tissues approach a critical interstitial fluid pressure of 9 mm Hg, any additional fluid will drastically increase interstitial fluid pressure and reduce capillary perfusion and oxygen delivery. Our “External Volume Expansion Effect Model” predicts the effect of vascular changes induced by preoperative external volume expansion that allow for greater volumes of fat to be successfully grafted.
CONCLUSIONS:These models confirm that initial fat grafting survival is limited by oxygen diffusion. Preoperative expansion increases oxygen diffusion capacity allowing for additional graft retention. These models provide a scientific framework for testing the current fat grafting theories.
Reduction in incidence of deep sternal wound infections: Random or real? Matros, Evan, MD; Aranki, Sary F., MD; Bayer, Lauren R., PA-C ...
Journal of thoracic and cardiovascular surgery/The Journal of thoracic and cardiovascular surgery/The journal of thoracic and cardiovascular surgery,
03/2010, Letnik:
139, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Objective Comorbidities predisposing cardiac surgical patients toward deep sternal wound infection, such as diabetes and obesity, are rising in the United States. Longitudinal analysis of risk ...factors, morbidity, and mortality was performed to assessed effects of these health trends on deep sternal wound infection rates. Methods In this retrospective analysis of all median sternotomies performed at a single institution from 1991 through 2006, demographic and surgical characteristics were identified from a prospective database. The cohort was separated into periods from 1992 through 2001 and 2002 through 2006 to identify longitudinal trends in risk factors for deep sternal wound infection. Univariate and matched multivariable analyses were performed. Results Overall, study population had increased comorbidities associated with deep sternal wound infection such as obesity, diabetes, and advanced age. Deep sternal wound infections were treated in 285 of 21,000 sternotomies performed during study period (1.35%). Deep sternal wound infection rates decreased from 1.57% to 0.88% in last 5 years. Rate of deep sternal wound infection was reduced among patients with diabetes from 3.2% to 1.0%. Multivariable analysis showed diabetes and smoking to be eliminated as risk factors in last 5 years. Prolonged bypass time was the only variable independently associated with deep sternal wound infection for the entire period. Thirty-day and 1-year mortalities for deep sternal wound infection did not change significantly. Conclusions Analysis of a large series of cardiac surgical patients demonstrates significant reduction in deep sternal wound infection incidence in 15 years. Introduction of perioperative intravenous insulin may explain some observed risk reduction. Efforts should focus on prevention, because mortality remains elevated.
Background:
Diabetic foot ulcers (DFUs) pose a significant clinical challenge for providers and patients, and often precede devastating complications such as infection, hospitalization, and ...amputation. Therefore, advanced treatment options are needed to facilitate the healing of chronic DFUs and improve outcomes in this high-risk population. Cryopreserved viable human amnion membrane allograft (vHAMA) has shown great promise in the treatment of recalcitrant DFUs as a supplement to standard of care (SOC). Placental grafts are rich in extracellular matrix proteins, growth factors, and cytokines, which can induce angiogenesis and dermal fibroblast proliferation, resulting in accelerated healing.
Methods:
In this prospective, multicenter single arm trial, 20 patients with nonhealing DFUs received weekly application of vHAMA, in addition to SOC, for up to 12 weeks. The primary study endpoint was proportion of healed wounds at 12 weeks. Secondary endpoints included proportion of wounds healed at 6 weeks, time to heal, and percentage area wound reduction. Subjects were evaluated for ulcer healing and assessed for adverse events at every treatment visit.
Results:
At study conclusion, 85% of patients receiving vHAMA healed. Ten wounds healed (50%) by 6 weeks, and 17 wounds (85%) healed by 12 weeks. The mean time to heal was 46.6 days (95% CI: 35.1–58.0), and the average number of vHAMAs used was 5.4 (SD: 3.25). The mean PAR was 86.3% (SD: 40.51).
Conclusions:
Aseptically processed, cryopreserved vHAMA should be considered as a safe and effective option for DFUs refractory to SOC therapy.
Background:
Shared decision-making (SDM) and effective risk communication improve patient satisfaction, adherence to treatment, and understanding of perioperative care pathways. Available risk ...calculators are less relevant for low-risk operations. The aim of this pilot study was to develop graphical risk visualization tools to enhance surgical SDM discussions preoperatively.
Methods:
Complications for reduction mammoplasty and skin grafting in a burns setting were sourced from the American College of Surgeons National Surgical Quality Improvement Program Surgical Risk Calculator, the American Society of Plastic Surgeons website, peer-reviewed literature, and available clinical data. Pre- and postoperative patient satisfaction data were collected from the published literature on Breast-Q patient-reported outcomes for reduction mammoplasty. Everyday risk comparisons were collected from a general online database search. Three distinct risk depiction tools (spiral, tile, and scatter plot) were developed in the Microsoft Office Suite. Anonymous REDCap surveys were sent to healthcare practitioners for feedback.
Results:
Twenty-six survey results were collected. Twenty-four respondents (92%) agreed these graphics would be useful for SDM discussions. Nineteen respondents (73%) either agreed or strongly agreed that these graphics depicted risk in a meaningful way. Fifteen respondents (58%) indicated they would use these graphics in daily practice. The majority of respondents preferred the spiral design (58%). Areas for improvement included design simplification and written explanations to accompany graphics. Feedback from the survey was incorporated into the spiral design.
Conclusions:
Risk visualization tools meaningfully depict surgical risks to improve communication in SDM. This study proposes a tool that can be adapted for many surgical procedures.
Periodic wound debridement promotes healing in chronic wounds. Low-frequency ultrasonic debridement (LFUD) is a promising adjunct to wound care, which offers relatively painless debridement and ...bacterial biofilm destruction. We performed LFUD on 17 patients over 8 months, with a minimum follow-up of 3 months. Nine of the wounds (53%) healed primarily or with the aid of a skin graft. Six additional patients (35%) experienced a wound-size reduction of at least 50%. The remaining 2 patients (12%), one with sickle cell anemia and one with a venous stasis ulcer, had reductions in wound area of 20%-30%. None of the patients required initiation of antibiotic treatment after starting LFUD. LFUD has had an early favorable experience in our institution. Further randomized clinical studies are required to better define the mechanism of action and the patient populations most appropriate for this modality.
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