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Curricular development and modification involve first identifying a problem and then performing a needs assessment, which can guide the design of curricular components. Pedagogical changes, coupled with reductions in curricular time for gross anatomy, pose challenges and impose restrictions within medical school curricula. In order to make anatomy education effective and efficient, it is important to determine the anatomy considered essential for medical education through a targeted needs assessment. In this study, 50 adult primary care resident physicians in family medicine (FM) and internal medicine (IM) were surveyed to assess the importance of 907 anatomical structures, or groups of structures, across all anatomical regions from a curated list based on the boldface terms in four primary anatomy texts. There were no statistically significant differences in the ratings of structures between the two groups for any anatomical region. In total, 17.0% of structures, or groups of structures, were classified as essential, 58.0% as more important, 24.4% as less important, and 0.7% as not important. FM residents rated tissues classified as skeleton, nerves, fasciae, anatomical spaces, blood vessels, lymphatics, and surface anatomy (p < 0.0001) significantly higher than IM residents, but there were no differences in the rating of muscles or organs (p > 0.0056). It was notable that 100.0% of cranial nerves were classified as essential, and 94.5% of surface anatomy structures were classified as essential or more important. It is proposed that results of this study can serve to inform curricular development and revision. [ABSTRACT FROM AUTHOR]

Background: Acute oropharyngeal hemorrhage is a serious complication for patients with oropharyngeal squamous cell carcinoma (OPSCC), particularly in patients with a history of radiation therapy (RT). Methods: Retrospective case series from at a tertiary care center for treated patients with HPV‐positive OPSCC presenting with oropharyngeal hemorrhage. Results: Median time from completion of chemoradiation to first hemorrhagic event was 186 days (range 66–1466 days). Seven patients (58%) required intervention to secure their airway. All patients were evaluated for endovascular intervention, six (50%) were embolized. Eight patients (67%) had a second hemorrhagic event; median time to second bleed was 22 days (range 3–90 days). Conclusions: Acute oropharyngeal hemorrhage is a sequelae following treatment for HPV‐positive OPSCC. The majority of bleeds occurred within a year of completion of treatment. While more research is needed to determine optimal treatment paradigms, endovascular intervention should be considered, even if noninvasive imaging does not demonstrate active bleeding. [ABSTRACT FROM AUTHOR]

Background: Current digital cell imaging systems perform peripheral blood smear (PBS) analysis in limited regions of the PBS and require the support of manual microscopy without achieving full digital microscopy. We report a multicenter study that validated the Scopio Labs X100 Full Field PBS, a novel digital imaging system that utilizes a full field view approach for cell recognition and classification, in a decision support system mode. Methods: We analyzed 335 normal and 310 abnormal PBS from patients with various clinical conditions and compared the performance of Scopio's Full Field PBS as the test method, with manual PBS analysis as the reference method. Deming regression analysis was utilized for comparisons of WBC and platelet estimates. Measurements of WBC and platelet estimation accuracy along with the agreement on RBC morphology evaluation were performed. Reproducibility and repeatability (R&R) of the system were also evaluated. Results: Scopio's Full Field PBS WBC accuracy was evaluated with an efficiency of 96.29%, sensitivity of 87.86%, and specificity of 97.62%. The agreement between the test and reference method for RBC morphology reached 99.77%, and the accuracy for platelet estimation resulted in an efficiency of 94.89%, sensitivity of 90.00%, and specificity of 96.28%, with successful R&R tests. The system enabled a comprehensive review of full field PBS as shown in representative samples. Conclusions: Scopio's Full Field PBS showed a high degree of correlation of all tested parameters with manual microscopy. The novel full field view of specimens facilitates the long‐expected disengagement between the digital application and the manual microscope. [ABSTRACT FROM AUTHOR]

Aims: To determine if neurologic symptoms at admission can predict adverse outcomes in patients with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). Methods: Electronic medical records of 1053 consecutively hospitalized patients with laboratory‐confirmed infection of SARS‐CoV‐2 from one large medical center in the USA were retrospectively analyzed. Univariable and multivariable Cox regression analyses were performed with the calculation of areas under the curve (AUC) and concordance index (C‐index). Patients were stratified into subgroups based on the presence of encephalopathy and its severity using survival statistics. In sensitivity analyses, patients with mild/moderate and severe encephalopathy (defined as coma) were separately considered. Results: Of 1053 patients (mean age 52.4 years, 48.0% men [n = 505]), 35.1% (n = 370) had neurologic manifestations at admission, including 10.3% (n = 108) with encephalopathy. Encephalopathy was an independent predictor for death (hazard ratio [HR] 2.617, 95% confidence interval [CI] 1.481–4.625) in multivariable Cox regression. The addition of encephalopathy to multivariable models comprising other predictors for adverse outcomes increased AUCs (mortality: 0.84–0.86, ventilation/ intensive care unit [ICU]: 0.76–0.78) and C‐index (mortality: 0.78 to 0.81, ventilation/ICU: 0.85–0.86). In sensitivity analyses, risk stratification survival curves for mortality and ventilation/ICU based on severe encephalopathy (n = 15) versus mild/moderate encephalopathy (n = 93) versus no encephalopathy (n = 945) at admission were discriminative (p < 0.001). Conclusions: Encephalopathy at admission predicts later progression to death in SARS‐CoV‐2 infection, which may have important implications for risk stratification in clinical practice. [ABSTRACT FROM AUTHOR]

Summary: The inflammatory response to SARS/CoV‐2 (COVID‐19) infection may contribute to the risk of thromboembolic complications. α‐Defensins, antimicrobial peptides released from activated neutrophils, are anti‐fibrinolytic and prothrombotic in vitro and in mouse models. In this prospective study of 176 patients with COVID‐19 infection, we found that plasma levels of α‐defensins were elevated, tracked with disease progression/mortality or resolution and with plasma levels of interleukin‐6 (IL‐6) and D‐dimers. Immunohistochemistry revealed intense deposition of α‐defensins in lung vasculature and thrombi. IL‐6 stimulated the release of α‐defensins from neutrophils, thereby accelerating coagulation and inhibiting fibrinolysis in human blood, imitating the coagulation pattern in COVID‐19 patients. The procoagulant effect of IL‐6 was inhibited by colchicine, which blocks neutrophil degranulation. These studies describe a link between inflammation and the risk of thromboembolism, and they identify a potential new approach to mitigate this risk in patients with COVID‐19 and potentially in other inflammatory prothrombotic conditions. [ABSTRACT FROM AUTHOR]

Objective: Sinonasal inverted papilloma (IP) is a typically benign sinonasal tumor with a tendency to recur and the potential for malignant transformation. Varying degrees of dysplasia may be present, of which carcinoma in situ (CIS) is most advanced. We hereby describe the biological and clinical behavior of IP with CIS (IPwCIS).Study Design: Retrospective cohort.Setting: Tertiary academic referral center.Subjects and Methods: Patients who underwent surgical resection for IP between 2002 and 2017. Pertinent clinical data were obtained, and all IPwCIS cases were histologically confirmed.Results: In total, 37 of 215 cases (17.2%) were identified with IPwCIS. Mean age was 57 years and 86.5% of patients were male. Median follow-up was 82 months, and the recurrence rate was 27%. The maxillary sinus was the most common primary site (37.8%) and 14 tumors (37.8%) demonstrated multifocal attachment, which was associated with recurrence (odds ratio [OR], 9.7; 95% confidence interval [CI], 1.4-112.8; P = .028). IPwCIS was also associated with multiple recurrences (OR, 2.71; 95% CI, 1.246-5.814; P = .021). Most patients were treated with surgery alone (89.1%) and 4 patients received adjuvant radiotherapy (8.1%). Only 1 patient (2.7%) demonstrated malignant transformation after definitive surgery.Conclusions: IPwCIS represents the most severe degree of dysplasia prior to malignant transformation and is associated with higher recurrence rate and multifocal involvement but low rate of conversion to invasive carcinoma. The need for adjuvant therapy remains controversial, and further research into the etiology of the disease is warranted. [ABSTRACT FROM AUTHOR]

Aims: Adenomyoepithelioma (AME) and adenoid cystic carcinoma (ACC) of the breast have been noted to occur simultaneously, raising the possibility that AME may represent a related or precursor lesion to ACC. ACC frequently harbours genetic rearrangement of the MYB gene. We sought to clarify the relationship between AME and ACC by comparing their rates of MYB expression by IHC and MYB rearrangement by FISH. Methods and results: IHC and FISH for MYB rearrangement were performed on paraffin‐embedded sections of 11 breast ACCs, 11 non‐breast ACCs and 11 breast‐AMEs. Using FISH, five of eight (63%) interpretable breast ACCs demonstrated MYB gene rearrangement. Nine of 11 (81%) breast ACCs demonstrated MYB expression (range = 20–95%). Of the three FISH‐negative breast ACCs, two were solid variant and demonstrated strong MYB expression by IHC. Of the 10 interpretable non‐breast ACCs, six showed MYB rearrangement, all of which were conventional type. Nine of these 11 (81%) cases showed MYB immunoexpression (range = 10–90%), including three solid‐variant cases which were negative by FISH. No MYB rearrangements were detected by FISH in 10 interpretable AMEs. However, three of 11 cases (27%) showed weak to moderate MYB expression by IHC (range = 10–40%). Conclusions: Our results indicate that AMEs do not harbour MYB gene rearrangement. IHC for MYB may be helpful in diagnosing FISH‐negative cases of ACC, particularly the diagnostically more difficult solid variants. However, weak to moderate MYB expression in a subset of AMEs highlights not only a potential diagnostic pitfall, but also shared pathophysiology with ACC worth investigating further at the genomic level. [ABSTRACT FROM AUTHOR]

Objective: Olfactory neuroblastoma and the management of neck disease has posed considerable challenges to the treating physician. The aims of the study were to determine the incidence and factors influencing neck disease and to identify at-risk patients with cervical node-negative disease at presentation.Study Design: Multicenter case series with retrospective chart review.Setting and Subjects: In sum, 113 patients with a histopathologic diagnosis of olfactory neuroblastoma across 6 tertiary hospitals in Australia and the United States.Methods: Treatment modalities for the primary site and neck included surgery, radiotherapy, and combined therapy. Treatment outcomes were measured in relation to date of primary treatment, and long-term follow-up was recorded. Disease-free survival was calculated as time for patients to develop delayed neck disease following primary treatment.Results: A total of 113 patients (46 females, 49.7 ± 13.2 years) were identified with a median follow-up of 41.5 months (interquartile range, 58.2); 7.1% of patients presented with primary neck disease, while 8.8% of patients presented with delayed neck disease. Neck disease was present in patients with Hyams grade II (22.2%), III (55.6%), and IV (22.2%) lesions (χ(2) = 5.66, P = .13). Histologic grade was higher in patients with primary neck disease (χ(2) = 16.22, P = .001). Positive surgical margins were associated with a higher risk of delayed neck disease as compared with clear surgical margin (17.9% vs 5%, P = .034).Conclusion: Neck metastasis is an important clinical consideration for olfactory neuroblastoma at presentation and in surveillance. Primary treatment of the neck could be considered in select patients. Long-term surveillance of the neck and primary site is essential. [ABSTRACT FROM AUTHOR]

Background: To identify computer extracted in vivo dynamic contrast enhanced (DCE) MRI markers associated with quantitative histomorphometric (QH) characteristics of microvessels and Gleason scores (GS) in prostate cancer.Methods: This study considered retrospective data from 23 biopsy confirmed prostate cancer patients who underwent 3 Tesla multiparametric MRI before radical prostatectomy (RP). Representative slices from RP specimens were stained with vascular marker CD31. Tumor extent was mapped from RP sections onto DCE MRI using nonlinear registration methods. Seventy-seven microvessel QH features and 18 DCE MRI kinetic features were extracted and evaluated for their ability to distinguish low from intermediate and high GS. The effect of temporal sampling on kinetic features was assessed and correlations between those robust to temporal resolution and microvessel features discriminative of GS were examined.Results: A total of 12 microvessel architectural features were discriminative of low and intermediate/high grade tumors with area under the receiver operating characteristic curve (AUC) > 0.7. These features were most highly correlated with mean washout gradient (WG) (max rho = -0.62). Independent analysis revealed WG to be moderately robust to temporal resolution (intraclass correlation coefficient [ICC] = 0.63) and WG variance, which was poorly correlated with microvessel features, to be predictive of low grade tumors (AUC = 0.77). Enhancement ratio was the most robust (ICC = 0.96) and discriminative (AUC = 0.78) kinetic feature but was moderately correlated with microvessel features (max rho = -0.52).Conclusion: Computer extracted features of prostate DCE MRI appear to be correlated with microvessel architecture and may be discriminative of low versus intermediate and high GS. [ABSTRACT FROM AUTHOR]

Single-molecule fluorescence imaging has provided unprecedented access to the dynamics of ribosome function, revealing transient intermediate states that are critical to ribosome activity. Imaging platforms have now been developed that are capable of probing many hundreds of molecules simultaneously at temporal and spatial resolutions approaching the sub-millisecond time and the sub-nanometer scales. These advances enable both steady- and pre-steady state measurements of individual steps in the translation process as well as processive reactions. The data generated using these methods have yielded new, quantitative structural and kinetic insights into ribosomal activity. They have also shed light on the mechanisms of antibiotic targeting the translation apparatus, revealing features of the structure–function relationship that would be difficult to obtain by other means. This review provides an overview of the types of information that can be obtained using such imaging platforms and a blueprint for using the technique to assess how small-molecule antibiotics alter macromolecular functions. [ABSTRACT FROM AUTHOR]

Aims: To investigate the use of a computer-assisted technology for objective, cell-based quantification of molecular biomarkers in specified cell types in histopathology specimens, with the aim of advancing current visual estimation and pixel-level (rather than cellbased) quantification methods. Methods and results: Tissue specimens were multiplex immunostained to reveal cell structures, cell type markers, and analytes, and imaged with multispectral microscopy. The image data were processed with novel software that automatically delineates and types each cell in the field, measures morphological features, and quantifies analytes in different subcellular compartments of specified cells. The methodology was validated with the use of cell blocks composed of differentially labelled cultured cells mixed in known proportions, and evaluated on human breast carcinoma specimens for quantifying human epidermal growth factor receptor 2, estrogen receptor, progesterone receptor, Ki67, phospho-extracellular signal-related kinase, and phospho- S6. Automated cell-level analyses closely matched human assessments, but, predictably, differed from pixel-level analyses of the same images. Conclusions: Our method reveals the type, distribution, morphology and biomarker state of each cell in the field, and allows multiple biomarkers to be quantified over specified cell types, regardless of their abundance. It is ideal for studying specimens from patients in clinical trials of targeted therapeutic agents, for investigating minority stromal cell subpopulations, and for phenotypic characterization to personalize therapy and prognosis. [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis: Our goal was to develop a noninvasive, dynamic imaging method that would further the understanding of head and neck cancer (HNC) tumor growth and local spreading. We developed a novel orthotopic mouse model of HNC with a stable cell line expressing a red fluorescent protein gene to compare a molecular imaging tumor quantification with traditional caliper measurement.Methods: An HNC-tdT stable cell line expressing the tdTomato gene was established, which were injected into the floor of the mouth of nude mice. Tumor growth was constantly monitored using molecularimaging for up to 35 days. The tumors were further evaluated by histologic examination. Results: Established tumors consistently expressed fluorescent signals that were successfully imaged by molecular imaging during the study. Initial tumor development was detected earlier than caliper measurement would allow. The fluorescent signal quantities of tumors detected by the imaging correlated with the tumor sizes measured by calipers.Conclusions: This novel animal model represents an orthotopic human HNC model. The tumor can be detected earlier with molecular imaging thanby conventional external caliper measurement. Unlike surgical measurement, the tumor can be quantified without disturbing the tumor environment. This model has significant potential for HNC oncologic research. [ABSTRACT FROM AUTHOR]

Background. Patients with oropharyngeal squamous cell carcinoma (OPSCC) have been shown to have distinct outcome profiles ased on their human papillomavirus (HPV) status. The purpose of this study was to assess HPVrelated outcomes after transoral obotic surgery (TORS) with adjuvant therapy as indicated. Methods. This study consisted of a retrospective review of 50 patients w ith OPSCC within a prospective single-arm cohort study. Outcome measures included HPV status, margin status, relapse pattern, and survival. Results. Thirty-seven patients were HPV-positive (74.0%) with 34 patients (91.9%) being serotype-16. Negative margins were achieved in 92.3% (HPV-negative) and 94.6% (HPV-positive). In the HPV-negative group, there were no local recurrences and 1 patient had both regional and distant recurrence (7.7%). In the HPV-positive group, there were no local or regional recurrences and 2 patients (5.4%) had distant recurrences. There were no statistically significant differences in survival between the 2 cohorts (overall survival, disease-specific survival, disease-free survival). Conclusion. TORS as a primary surgical modality, followed by adjuvant therapy as indicated, offers disease control in both HPV-negative and HPV-positive groups. We believe that multi-institutional studies are warranted to further evaluate this novel approach for patients who are HPV negative and HPV positive. [ABSTRACT FROM AUTHOR]

Purpose: Computer aided detection (CAD) data analysis procedures are introduced and applied to derive composite diffuse optical tomography (DOT) signatures of malignancy in human breast tissue. In contrast to previous optical mammography analysis schemes, the new statistical approach utilizes optical property distributions across multiple subjects and across the many voxels of each subject. The methodology is tested in a population of 35 biopsy-confirmed malignant lesions. Methods: DOT CAD employs multiparameter, multivoxel, multisubject measurements to derive a simple function that transforms DOT images of tissue chromophores and scattering into a probability of malignancy tomogram. The formalism incorporates both intrasubject spatial heterogeneity and intersubject distributions of physiological properties derived from a population of cancer-containing breasts (the training set). A weighted combination of physiological parameters from the training set define a malignancy parameter (M), with the weighting factors optimized by logistic regression to separate training-set cancer voxels from training-set healthy voxels. The utility of M is examined, employing 3D DOT images from an additional subjects (the test set). Results: Initial results confirm that the automated technique can produce tomograms that distinguish healthy from malignant tissue. When compared to a gold standard tissue segmentation, this protocol produced an average true positive rate (sensitivity) of 89% and a true negative rate (specificity) of 94% using an empirically chosen probability threshold. Conclusions: This study suggests that the automated multisubject, multivoxel, multiparameter statistical analysis of diffuse optical data is potentially quite useful, producing tomograms that distinguish healthy from malignant tissue. This type of data analysis may also prove useful for suppression of image artifacts. [ABSTRACT FROM AUTHOR]

Introduction: Inverted papilloma (IP) is a benign but locally aggressive sinonasal tumor. Those localized to the maxillary sinus or medial maxillary wall have classically been removed through an external approach. In recent years, endoscopic removal has been advocated as an effective, minimally invasive approach. Successful endoscopic management is based on accurate intraoperative identification and complete resection of the tumor. The surgical management of the bone underlying the surface of an IP is less clearcut. Controversy exists as to whether the bony undersurface of an IP should be removed. In this article, histopathologic specimens and preoperative radiologic studies are prospectively examined to better understand the involvement of the bone underlying an inverted papilloma. Materials and Methods: A prospective study of patients with maxillary sinus IP treated with endoscopic or endoscopic-assisted resection over a 12-month period was conducted. Intraoperatively, the site of tumor attachment was identified, and a 1- to 2-cm wedge of bone with overlying tumor was removed en bloc and analyzed under light microscopy. Preoperative radiographic studies were analyzed with respect to bony changes in the area of the tumor pedicle. Results: On histopathologic analysis, the bony surface underlying the IP was irregular with multiple bony crevices in all nine cases. In two cases (22% of specimens), an isolated rest of normal-appearingsalivary gland and/or mucosal tissue was seen embedded in the underlying bone. Radiographic osteitic bony changes were seen at site of tumor attachment in 100% of cases. Conclusion: The irregularity of the bony surface may hinder complete tumor removal because microscopic rests of mucosa can be hidden within the bony crevices. Intraoperative removal of the bony surface at the site of tumor attachment may ensure a more complete removal. [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis: The study examined preoperative clinical characteristics that can be used to predict secure inferior margins of glottic squamous cell carcinoma extending toward the cricoid cartilage when performing organ preservation surgery of the larynx. Study Design: The study was retrospectively performed using 31 serially sectioned whole-organ total laryngectomy specimens with associated preoperative clinical data. Methods: Histopathologic and clinical variables including true vocal cord (TVC) fixation, cricoarytenoid joint invasion, subglottic extension (SGE) of tumor, and prior radiation were examined as independent and multivariate correlates of cricoid cartilage invasion. Results: All tumors with subglottic extension of 15 mm or less and without arytenoid fixation were free of cricoid invasion. Of tumors invading cricoid with subglottic extension of 15 mm or less, all had a fixed arytenoid cartilage and local cricoid invasion type only. Correcting for subglottic extension using multivariate analysis, cricoarytenoid joint invasion and fixed true vocal cord independently predicted cricoid invasion. However, in a multivariate model together, true vocal cord mobility adds no predictive power to cricoarytenoid joint invasion. Prior radiation of the larynx did not significantly change the predictive capacity of these variables. Conclusion: Preoperative assessment of arytenoid mobility and extent of subglottic extension are reliable predictors of cricoid invasion by glottic squamous cell carcinoma. Organ preservation surgery is oncologically safe in the setting of glottic squamous cell carcinoma with subglottic extension of 15 mm or less and without arytenoid fixation. [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis Perineural invasion (PNI) is increasingly being recognized as an important indicator of aggressiveness in head and neck squamous cell carcinoma. The mechanisms of PNI are poorly understood. Laminin-5, an important basement membrane constituent, has been shown to be essential in head and neck squamous cell carcinoma invasion and motility. We hypothesized that tumors exhibiting increased expression of laminin-5 are more likely to be neurotropic. Study Design Analysis of archived surgical specimens with and without PNI for presence and intensity of laminin-5 tumor staining. Methods Immunohistochemistry of archived head and neck squamous cell carcinoma specimens with known PNI was performed with anti-laminin-5 antibodies and appropriate positive and negative control specimens. The staining patterns were characterized as follows: A, few to no tumor cells positive; B, some peripheral cells positive; C, all peripheral cells positive; and D, almost all tumor cells positive. Statistical analysis was by χ2 analysis. Results Forty-six PNI-positive and 18 PNI-negative specimens were analyzed. The staining distribution for the PNI-positive specimens was as follows: 2% for A, 41% for B, 46% for C, and 11% for D. For tumors without PNI, the distribution was 28% for A, 50% for B, 22% for C, and 0% for D ( P = .005). In PNI-positive tumors, no significant difference in staining was seen between areas with and without PNI. Conclusions We found a significant correlation between laminin-5 staining and the presence of PNI in head and neck squamous cell carcinoma. Expression of laminin-5 by tumors is, possibly, an important step in the process of PNI. These preliminary findings support the concept that deposition of basement membrane constituents are required in the multistep process of nerve invasion. [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis The purpose of this study is to compare collateral tissue damage and wound healing in incisions created by electro-dissociation and conventional electrosurgery. Conventional electrosurgery has been used as an alternative to the scalpel to improve hemostasis. However, the heat generated by this instrument can cause tissue damage surrounding the incision, limiting its use around nerves and large blood vessels. A new technology, Coblation (Arthrocare Corp., Sunnyvale, CA), uses 'electro-dissociation' to achieve similar results by creating charged particles from a conductive medium to make an incision while simultaneously achieving hemostasis. This new approach to electrosurgery may reduce soft tissue damage. Study Design: Methods Two prospective, matched design experiments were performed. In experiment I, both devices were set at the same electrical power in watts and then used to create an incision on the tongue of rats. In experiment II, the electrical power settings of both devices were adjusted until they created incisions of the same size. Epithelial destruction and collateral tissue damage were measured in histologically prepared tissue in both experiments, and the wound healing process was observed in experiment II at 0, 3, 7, and 14 days after surgery. Results The results showed that the electro-dissociation method created significantly less epithelial destruction and collateral tissue damage in both experiments. Granulation tissue formation was also significantly less extensive in the electro-dissociation-induced incision after 7 and 14 days of recovery. Conclusions Wound healing may be faster than with conventional electrosurgery if the Coblation device is used. [ABSTRACT FROM AUTHOR]

Objective To evaluate the integration of AlloDerm (LifeCell Corp., The Woodlands, TX) in a field exposed to external-beam radiation (EBR) by analyzing graft thickness, fibroblast recellularization, and neovascularization. Study Design Randomized control. Methods Thirty-six male Sprague-Dawley rats (n = 36) were randomly assigned to four groups. One hind leg of each rat was exposed to 20 Gy of EBR; the other limb served as the nonirradiated control. Two weeks after irradiation, AlloDerm was implanted into both hind legs. Grafts were harvested at 3, 4, 6, and 14 weeks after implantation and underwent histological analyses. Results There was no statistically significant difference in graft thickness, fibroblast count, or neovascularization between the grafts placed in the irradiated bed and the controls (n = 33, P = .332, P = .336, and P = .057, respectively). However, at week 3, fibroblast counts in the graft placed in the field exposed to EBR were significantly lower than those of controls ( P = .019), although at week 14 the counts in the experimental limb were higher than those of the controls ( P = .002). Graft thickness ( P = .001) and fibroblast count ( P < .004) were lower at week 14 than at earlier time periods for both the experimental and control grafts. Conclusions In the rat model, graft thickness and neovascularization of the AlloDerm dermal implant do not appear to be adversely affected by a field that has received EBR. Fibroblast ingrowth may be hindered in the early postimplantation period but appears to normalize in the long term. Furthermore, overall graft thickness and fibroblast counts decrease over time, regardless of irradiation status. [ABSTRACT FROM AUTHOR]