Inattention to differences between animal strains is a potential cause of irreproducibility of basic science investigations. Accordingly, the authors' laboratory sought to ensure that cross-comparisons of results generated from studies of mandibular physiology utilizing the Sprague Dawley and Lewis rat strains are valid. The authors specifically investigated baseline histomorphometrics, bone mineral density, and biomechanical strength of the unaltered endogenous mandibles of the inbred, isogenic Lewis rat, and the outbred, nonisogenic Sprague Dawley rat to determine if they are indeed equal. The authors hypothesized that little difference would be found within these metrics.The authors' study utilized 20 male Lewis and Sprague Dawley rats, which underwent no manipulation other than final dissection and analysis. Ten rats from each strain underwent bone mineral density and biomechanical strength analysis. The remaining rats underwent histological analysis. Descriptive and bivariate statistics were computed and the P value was set at 0.05.Lewis rats had a significantly greater number of empty lacunae. Sprague Dawley rats exhibited a significantly greater ratio of bone volume-to-total volume, bone mineral density, tissue mineral density, bone volume fraction, and total mineral content. No differences were found during biomechanical testing.This study demonstrates that differences exist between the Lewis and Sprague Dawley rat within unaltered baseline mandibular tissue. However, these differences appear to have limited functional impact, as demonstrated by similar biomechanical strength metrics. Other specific differences not addressed in this manuscript may exist. However, the authors believe that researchers may confidently cross-compare results between the 2 strains, while taking into account the differences found within this study.

INTRODUCTION:Unanticipated postoperative readmissions are a grading metric directly linked to both the quality of patient care and physician reimbursement. However, little data exist to define factors responsible for these readmissions in the plastic surgery patient population. This study aims to identify patient risk factors contributing to unanticipated postoperative readmissions to optimize perioperative patient care and mitigate negative financial impact upon providers.METHODS:We present an institutional review board-approved study retrospective review of 819 plastic surgery patients undergoing operative procedures performed at our institution between January 1, 2013, and December 31, 2014. All unanticipated readmissions within 30 days of an operation were identified and subjected to statistical analysis in an effort to determine whether these readmissions were associated with identifiable patient risk factors.RESULTS:One hundred forty-nine (18.1%) of the 819 investigated patients underwent readmission, reoperation, or both within 30 postoperative days. Seventy-four (9%) patients required hospital readmission, alone; 55 (6.7%) underwent readmission with operative intervention; and 20 (2.4%) required outpatient operative intervention without readmission. Readmitted patients were significantly more likely to have a positive smoking history (P = 0.009), hypertension (P = 0.0008), congestive heart failure (P = 0.0015), chronic obstructive pulmonary disease (P = 0.023), a higher mean age (P = 0.0001), and a higher Charlson Comorbidity Score (P = 0.0001).CONCLUSIONS:These results identify risk factors associated with unanticipated postoperative readmissions specific to a plastic surgery patient population. With this information, practitioners can allocate appropriate perioperative resources and planning for patients at increased risk for readmission, thereby improving delivery of patient care and satisfying quality metrics linked to practitioner reimbursement.

PURPOSE: Unanticipated postoperative readmission will be a quality-directed metric linked to CMS reimbursement. In an effort to both optimize patient care and prevent negative financial implications, we have identified patient risk factors that contribute to unanticipated postoperative readmissions for plastic surgery patients. Building on this knowledge, the aim of this curret study is to create a risk index calculator to quantifiably predict the likelihood of 60-day postoperative readmissions. METHODS: An IRB approved retrospective review was done evaluating 671 randomly-selected patients undergoing procedures with the Plastic & Reconstructive Surgery service at our institution between January 1, 2013 and December 31, 2014. 60-day postoperative readmissions were identified for 58 (8.6%) patients. Logistical regression and backward variable selection with an inclusive p-value <0.30 yielded patient age, BMI, same-site procedure, renal disease, thyroid disease, CAD, COPD, and history of malignancy as variables associated with readmission. RESULTS: We used a linear combination rule with the associated variables associated with readmission to create a risk index calculator. The product of the risk calculator yields a Risk Index Value (RIV). The RIV corresponds to a Predicted Percentage (PP) representing the probability of a 60-day postoperative readmission. CONCLUSION: Patient risk factors associated with unanticipated postoperative readmissions can be used to calculate the percentage likelihood of 60-day postoperative readmission. With this information, practitioners can provide appropriate resources for patients at increased risk of readmission ultimately satisfying quality-directed metrics linked with CMS reimbursement as well as optimizing the delivery of patient care. DISCLOSURE/FINANCIAL SUPPORT:None of the authors has a financial interest in any of the products, devices, or drugs mentioned in this manuscript.

Purpose: The vascularity, bone mineral density distribution, and histomorphometric data between the inbred, isogenic Lewis rat and the outbred, nonisogenic Sprague Dawley rat within mandibular distraction osteogenesis (MDO) were evaluated to allow future researchers to compare the results generated from these 2 animals. We hypothesized that little difference would be found between the 2 strains within these metrics.Materials and Methods: We implemented a comparative study between the Lewis and Sprague Dawley rat strains within MDO. The sample was composed of 17 male Lewis and 17 male Sprague Dawley rats that underwent surgical external fixation and distraction. The rats' hemimandibles were distracted to a total distance of 5.1 mm. After 28 days of consolidation, 9 rats from each group underwent bone mineral density distribution analysis. The remaining rats from each group were analyzed for the vascular and histologic metrics. Descriptive and bivariate statistics were computed, and the P value was set at .05.Results: We demonstrated successful MDO in all the rats, with no significant difference found in the histologic or bone mineral density distribution metrics. No significant differences were found in any of the vascular metrics, with the exception of vascular separation, which was not normalized to the mandibular volume (P = .048).Conclusions: The results of the present study have demonstrated that little dissimilarity exists between the isogenic Lewis and outbred Sprague Dawley models of MDO. Thus, researchers can confidently compare the gross results between the 2 strains, with consideration of the very small differences between the 2 models. For studies that require an isogenic strain, the Lewis rat is an apt surrogate for the Sprague Dawley strain. (C) 2016 American Association of Oral and Maxillofacial Surgeons

Background. Bony non-unions arising in the aftermath of collateral radiation injury are commonly managed with vascularized free tissue transfers. Unfortunately, these procedures are invasive and fraught with attendant morbidities. This study investigated a novel, alternative treatment paradigm utilizing adipose-derived stem cells (ASCs) combined with angiogenic deferoxamine (DFO) in the rat mandible.Methods. Rats were exposed to a bioequivalent dose of radiation and mandibular osteotomy. Those exhibiting non-unions were subsequently treated with surgical debridement alone or debridement plus combination therapy. Radiographic and biomechanical outcomes were assessed after healing.Results. Significant increases in biomechanical strength and radiographic metrics were observed in response to combination therapy (p < .05). Importantly, combined therapy enabled a 65% reduction in persisting non-unions when compared to debridement alone.Conclusion. We support the continued investigation of this promising combination therapy in its potential translation for the management of radiation-induced bony pathology. (C) 2015 Wiley Periodicals, Inc.

Background. The purpose of this study was to measure the histologic and histomorphometric effects of parathyroid hormone (PTH) treatment on irradiated bone undergoing distraction osteogenesis (DO).Methods. Thirty-four rats were divided into 3 groups. The control group underwent DO and the radiation control group underwent radiotherapy (RT) before DO. The PTH group underwent RT and received PTH during DO. Quantitative histology and histomorphometry were performed.Results. RT resulted in a depletion of osteocytes and increase in empty lacunae. Treatment with PTH resulted in an increase in osteocyte counts and decrease in empty lacunae (p < .05), restoring osteocytes to levels seen in nonradiated bone (p = .121). RT decreased bone volume to tissue volume (BV-TV) ratio and increased osteoid volume to tissue volume (OV-TV) ratio, signifying increased immature bone formation. PTH treatment restored OV-TV ratio to that observed in nonradiated bone.Conclusion. PTH treatment of irradiated bone enhanced bone regeneration and restored osteocyte counts and OV-TV ratio to levels comparable to nonradiated bone. (C) 2016 Wiley Periodicals, Inc.

74 30-day VTE, including patients with deep venous thrombosis (DVT) or pulmonary embolus (PE). Regression-based analysis and subsequent bootstrap analysis allowed creation of a weighted, open VHR specific VTE risk assessment model. Risk factor weighting was performed based on beta coefficients. The newly created weighted RAM was then used to risk-stratify patients for both 30-day VTE risk and 30-day risk for other medical and surgical complications.

Background: Radiotherapy is known to be detrimental to bone and soft-tissue repair. Bone marrow stromal cells have been shown to enhance bone regeneration during distraction osteogenesis following radiation therapy. The authors posit that transplanted bone marrow stromal cells will significantly augment the mandibular vascularity devastated by radiation therapy.Methods: Nineteen male Lewis rats were split randomly into three groups: distraction osteogenesis only (n = 5), radiation therapy plus distraction osteogenesis (n = 7), and radiation therapy plus distraction osteogenesis with intraoperative placement of 2 million bone marrow stromal cells (n = 7). A mandibular osteotomy was performed, and an external fixator device was installed. From postoperative days 4 through 12, rats underwent a gradual 5.1 mm distraction followed by a 28-day consolidation period. On postoperative day 40, Microfil was perfused into the vasculature and imaging commenced. Vascular radiomorphometric values were calculated for regions of interest. An analysis of variance with post hoc Tukey or Games-Howell tests was used, dependent on data homogeneity.Results: Stereologic analysis indicated significant remediation in vasculature in the bone marrow stromal cell group compared with the radiation therapy/distraction osteogenesis group. Each of five metrics idicated significant improvements from radiation therapy/distraction osteogenesis to the bone marrow stromal cell group, with no difference between the bone marrow stromal cell group and the distraction osteogenesis group.Conclusions: Bone marrow stromal cells used together with distraction osteogenesis can rejuvenate radiation-impaired vasculogenesis in the mandible, reversing radiation therapy-induced isotropy and creating a robust vascular network. Bone marrow stromal cells may offer clinicians an alternative reconstructive modality that could improve the lifestyle of patients with hypovascular bone.

Background Although expander-based breast reconstruction is the most commonly used method of reconstruction worldwide, it continues to be plagued with complication rates as high as 60% when radiotherapy is implemented. We hypothesized that quantitative measures of radiotherapy-induced vascular injury can be mitigated by utilizing amifostine in a murine model of expander-based breast reconstruction. Methods 30 rats were divided into three groups: expander placement (Control), expander placement followed by radiotherapy (XRT), and expander placement followed by radiotherapy with amifostine (AMF/XRT). All groups underwent placement of a sub-latissimus tissue expander. After a 45 day recovery period, all groups underwent vascular perfusion and micro-CT analysis. Results Micro-CT analysis was used to calculate vessel volume fraction (VVF), vessel number (VN), and vessel separation (VSp). A significant increase in VN was seen in the XRT group as compared to the Control (p = 0.021) and the AMF/XRT (p = 0.027). There was no difference between Control and AMF/XRT (p = 0.862). VVF was significantly higher in XRT than either Control (p = 0.043) and AMF/XRT (p = 0.040), however no difference was seen between Control and AMF/XRT (p = 0.980). VSp of XRT was smaller when compared to both Control and AMF/XRT specimens (p = 0.05 and p = 0.048, respectively), and no difference was seen between Control and AMF/XRT (p = 0.339). Conclusions Amifostine administered prior to radiotherapy preserved vascular metrics similar to those of non-radiated specimens. Elevated vascularity demonstrated within the XRT group was not seen in either the Control or AMF/XRT groups. These results indicate that amifostine protects soft tissue in our model from a radiotherapy-induced pathologic vascular response.

Despite its therapeutic role in head and neck cancer, radiation administration degrades the biomechanical properties of bone and can lead to pathologic fracture and osteoradionecrosis. Our laboratories have previously demonstrated that prophylactic amifostine administration preserves the biomechanical properties of irradiated bone and that Raman spectroscopy accurately evaluates bone composition ex vivo. As such, we hypothesize that Raman spectroscopy can offer insight into the temporal and mechanical effects of both irradiation and amifostine administration on bone to potentially predict and even prevent radiation-induced injury. Male Sprague–Dawley rats (350–400 g) were randomized into control, radiation exposure (XRT), and amifostine pre-treatment/radiation exposure groups (AMF-XRT). Irradiated animals received fractionated 70 Gy radiation to the left hemi-mandible, while AMF-XRT animals received amifostine just prior to radiation. Hemi-mandibles were harvested at 18 weeks after radiation, analyzed via Raman spectroscopy, and compared with specimens previously harvested at 8 weeks after radiation. Mineral (ρ958) and collagen (ρ1665) depolarization ratios were significantly lower in XRT specimens than in AMF-XRT and control specimens at both 8 and 18 weeks. amifostine administration resulted in a full return of mineral and collagen depolarization ratios to normal levels at 18 weeks. Raman spectroscopy demonstrates radiation-induced damage to the chemical composition and ultrastructure of bone while amifostine prophylaxis results in a recovery towards normal, native mineral and collagen composition and orientation. These findings have the potential to impact on clinical evaluations and interventions by preventing or detecting radiation-induced injury in patients requiring radiotherapy as part of a treatment regimen.

AMERICAN SOCIETY OF PLASTIC SURGEONS PLASTIC & RECONSTRUCTIVE SURGERY PRS GLOBAL OPEN ASPS EDUCATION NETWORK AMERICAN SOCIETY OF PLASTIC SURGEONS PLASTIC & RECONSTRUCTIVE SURGERY PRS GLOBAL OPEN ASPS EDUCATION NETWORK

BACKGROUND:Immediate expander-based breast reconstruction after mastectomy is a prevalent option for many women with breast cancer. When coupled with adjuvant radiation therapy, however, radiation-induced skin and soft-tissue injury diminish the success of this reconstructive technique. The authors hypothesize that prophylactic administration of the cytoprotectant amifostine will reduce soft-tissue complications from irradiation, aiding expander-based reconstruction.METHODS:Sprague-Dawley rats were divided into two groups: operative expander placement (expander group) and operative sham (sham group). Expander specimens received a sublatissimus tissue expander with a 15-cc fill volume; shams underwent identical procedures without expanders. Experimental groups were further divided into control specimens receiving no further intervention, radiation therapy-only specimens receiving human-equivalent irradiation, and amifostine plus radiation therapy specimens receiving both amifostine and human-equivalent irradiation. After a 45-day recovery period, animals were evaluated grossly and with ImageJ analysis for skin and soft-tissue complications.RESULTS:None of the control, radiation therapy-alone, or amifostine plus radiation therapy sham specimens showed skin and soft-tissue complications. For expander animals, significantly fewer amifostine plus radiation therapy specimens [four of 13 (30 percent)] demonstrated skin and soft-tissue complications compared with radiation therapy-alone specimens [nine of 13 (69 percent); p = 0.041]. ImageJ evaluation of expander specimens demonstrated a significant increase in skin and soft-tissue necrosis for radiation therapy-alone specimens (12.94 percent) compared with animals receiving amifostine plus radiation therapy (6.96 percent) (p = 0.019).CONCLUSIONS:Amifostine pretreatment significantly reduced skin and soft-tissue complications. These findings demonstrate that amifostine prophylaxis provides protection against radiation-induced skin and soft-tissue injury in a murine model of expander-based breast reconstruction.

Although often beneficial in the treatment of head and neck cancer (HNC), radiation therapy (XRT) leads to the depletion of vascular supply and eventually decreased perfusion of the tissue. Specifically, previous studies have demonstrated the depletion of vessel volume fraction (VVF) and vessel thickness (VT) associated with XRT. Amifostine (AMF) provides protection from the detrimental effects of radiation damage, allowing for reliable postirradiation fracture healing in the murine mandible. The purpose of this study is to investigate the prophylactic ability of AMF to protect the vascular network in an irradiated field. Sprague -Dawley rats (n = 17) were divided into 3 groups: control (C, n = 5), radiated (XRT, n = 7), and radiated mandibles treated with Amifostine (AMF XRT, n = 5). Both groups receiving radiation underwent a previously established, human equivalent dose of XRT totaling 35 Gy, equally fractionated over 5 days. The AMF XRT group received a weight dependent (0.5 mg AMF/5 g body weight) subcutaneous injection of AMF 45 min prior to XRT. Following a 56-day recovery period, mandibles were perfused, dissected, and imaged with mu CT. ANOVA was used for comparisons between groups and p < 0.05 was considered statistically significant. Stereologic analysis demonstrated a significant and quantifiable restoration of VT in AMF treated mandibles as compared to those treated with radiation alone (0.061 +/- 0.011 mm versus 0.042 +/- 0.004 mm, p = 0.027). Interestingly, further analysis demonstrated no significant difference in VT between control mandibles and those treated with AMF (0.067 +/- 0.016 mm versus 0.061 +/- 0.011 mm, p = 0.633). AMF treatment also showed an increase in VVF, however those results were not statistically significant from VVF values demonstrated by the XRT group. Our data support the contention that AMF therapy acts prophylactically to protect vessel thickness. Based on these findings, we support the continued investigation of this treatment paradigm in its potential translation for the prevention of vascular depletion after radiotherapy. (C) 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Page, Erin E. BS; Deshpande, Sagar S. BS; Nelson, Noah S.; Felice, Peter A. MD; Donneys, Alexis MD, MS; Rodriguez, Jose J.; Deshpande, Samir S.; Buchman, Steven R. MD Author Information

AMERICAN SOCIETY OF PLASTIC SURGEONS PLASTIC & RECONSTRUCTIVE SURGERY PRS GLOBAL OPEN ASPS EDUCATION NETWORK AMERICAN SOCIETY OF PLASTIC SURGEONS PLASTIC & RECONSTRUCTIVE SURGERY PRS GLOBAL OPEN ASPS EDUCATION NETWORK

Introduction: Head and neck cancer is a debilitating and disfiguring disease. Although numerous treatment options exist, an array of debilitating side effects accompany them, causing physiological and social problems. Distraction osteogenesis (DO) can avoid many of the pathologies of current reconstructive strategies; however, due to the deleterious effects of radiation on bone vascularity, DO is generally ineffective. This makes investigating the effects of radiation on neovasculature during DO and creating quantifiable metrics to gauge the success of future therapies vital. The purpose of this study was to develop a novel isogenic rat model of impaired vasculogenesis of the regenerate mandible in order to determine quantifiable metrics of vascular injury and associated damage.Methods: Male Lewis rats were divided into two groups: DO only (n = 5) AND Radiation Therapy (XRT) + DO (n = 7). Afterwards, a distraction device was surgically implanted into the mandible. Finally, they were distracted a total of 5.1 mm. Animals were perfused with a radiopaque casting agent concomitant with euthanasia, and subsequently demineralization, microcomputed tomography, and vascular analysis were performed.Results: Vessel volume fraction, vessel thickness, vessel number, and degree of anisotropy were diminished by radiation. Vessel separation was increased by radiation.Conclusion: The DO group experienced vigorous vessel formation during distraction and neovascularization with a clear, directional progression, while the XRT/DO group saw weak vessel formation during distraction and neovascularization. Further studies are warranted to more deeply examine the impairments in osteogenic mechanotransductive pathways following radiation in the murine mandible. This isogenic model provides quantifiable metrics for future studies requiring a controlled approach to immunogenicity. (C) 2014 Elsevier Inc All rights reserved.

AMERICAN SOCIETY OF PLASTIC SURGEONS PLASTIC & RECONSTRUCTIVE SURGERY PRS GLOBAL OPEN ASPS EDUCATION NETWORK AMERICAN SOCIETY OF PLASTIC SURGEONS PLASTIC & RECONSTRUCTIVE SURGERY PRS GLOBAL OPEN ASPS EDUCATION NETWORK

BackgroundRadiotherapy (XRT) exerts detrimental collateral effects on bone tissue through mechanisms of vascular damage and impediments to osteocytes, ultimately predisposing patients to the debilitating problems of late pathologic fractures and nonunions. We posit that angiogenic therapy will reverse these pathologic effects in a rat model of radiated fracture healing.MethodsThree groups of rats underwent mandibular osteotomy. Radiated groups received a fractionated 35-Gy dose before surgery. The deferoxamine (DFO) group received local injections postoperatively. A 40-day healing period was allowed before histology. Analysis of variance (ANOVA; p<.05) was used for group comparisons.ResultsRadiated fractures revealed a significantly decreased osteocyte count and corresponding increase in empty lacunae when compared to nonradiated fractures (p=.001). With the addition of DFO, these differences were not appreciated. Further, a 42% increase in bony unions was observed after DFO therapy.ConclusionTargeting angiogenesis is a useful means for promoting osteocyte survival and preventing bone pathology after XRT. (c) 2014 Wiley Periodicals, Inc. Head Neck 37: 1261-1267, 2015

AMERICAN SOCIETY OF PLASTIC SURGEONS PLASTIC & RECONSTRUCTIVE SURGERY PRS GLOBAL OPEN ASPS EDUCATION NETWORK AMERICAN SOCIETY OF PLASTIC SURGEONS PLASTIC & RECONSTRUCTIVE SURGERY PRS GLOBAL OPEN ASPS EDUCATION NETWORK