Residency Selection in Otolaryngology: Past, Present, & Future

OBJECTIVES

To examine the otolaryngology residency selection process, including past experiences based on the medical literature and survey analysis of our present practices to generate recommendations for future selection system design.

METHODS

A mixed-methods study, including a scoping review and a cross-sectional survey, was completed. Four databases were assessed for articles on otolaryngology residency selection published from January 1, 2016 through December 31, 2020. A 36-question survey was developed and distributed to 114 otolaryngology program directors. Descriptive and thematic analysis was performed.

RESULTS

Ultimately, 67 of 168 articles underwent data abstraction and assessment. Three themes surfaced during the analysis: effectiveness, efficiency, and equity. Regarding the survey, there were 62 participants (54.4% response rate). The three most important goals for the selection process were: (1) to fit the program culture, (2) to make good colleagues, and (3) to contribute to the program's diversity. The three biggest 'pain points' were as follows: (1) Large volume of applications, (2) Lack of reliable information about personal characteristics, and (3) Lack of reliable information about a genuine interest in the program.

CONCLUSIONS

Within this study, the depth and breadth of the literature on otolaryngology residency selection have been synthesized. Additionally, baseline data on selection practices within our specialty has been captured. With an informed understanding of our past and present, we can look to the future. Built upon the principles of person-environment fit theory, our proposed framework can guide research and policy discussions regarding the design of selection systems in otolaryngology, as we work to achieve more effective, efficient, and equitable outcomes.

LEVEL OF EVIDENCE

N/A Laryngoscope, 133:2929-2941, 2023.

Intersectionality of Race, Ethnicity, and Gender in the Otolaryngology Match From 2013 to 2019

OBJECTIVES

Racial, ethnic, and gender disparities in the otolaryngology-head and neck surgery (OHNS) match have been described individually, but not intersectionally. Intersectionality recognizes how multiple forms of discrimination (e.g., sexism, racism) can have a combined effect. The objective of this study was to analyze racial, ethnic, and gender disparities in the OHNS match using an intersectional approach.

METHODS

Cross-sectional evaluation of data from otolaryngology applicants from the Electronic Residency Application Service (ERAS) and of corresponding otolaryngology residents from the Accreditation Council for Graduate Medical Education (ACGME) from 2013 to 2019. Data were stratified by race, ethnicity, and gender. The Cochran-Armitage tests assessed trends over time in the proportions of applicants and corresponding residents. Chi-square tests with Yates' continuity correction were performed to evaluate differences between the aggregate proportions of applicants and corresponding residents.

RESULTS

The proportion of White men in the resident pool was increased compared to the applicant pool (ACGME 0.417, ERAS 0.375; Δ + 0.042; 95% CI 0.012 to 0.071; p = 0.03). This was also the case for White women (ACGME 0.206, ERAS 0.175; Δ + 0.031; 95% CI 0.007 to 0.055; p = 0.05). In contrast, there was a smaller proportion of residents compared to applicants among Multiracial men (ACGME 0.014, ERAS 0.047; Δ - 0.033; 95% CI -0.043 to -0.023; p < 0.001) and Multiracial women (ACGME 0.010, ERAS 0.026; Δ - 0.016; 95% CI -0.024 to -0.008; p < 0.001).

CONCLUSION

The findings of this study imply that White men have a persistent advantage, while several racial, ethnic, and gender minorities are disadvantaged in the OHNS match. Further research is necessary to examine why these differences exist in residency selection, including evaluation during the screening, reviewing, interviewing, and ranking stages. Laryngoscope, 133:2558-2563, 2023.

Defining the Performance of Clinician's Ability to Screen for Laryngeal Mass From Voice

OBJECTIVE

Defining a clinician's ability to perceptually identify mass from voice will inform the feasibility, design priorities, and performance standards for tools developed to screen for laryngeal mass from voice. This study defined clinician ability of and examined the impact of expertise on screening for laryngeal mass from voice.

STUDY DESIGN

Task comparison study between experts and nonexperts rating voices for the probability of a laryngeal mass.

SETTING

Online, remote.

METHODS

Experts (voice-focused speech-language pathologists and otolaryngologists) and nonexperts (general medicine providers) rated 5-s/i/voice samples (with pathology defined by laryngoscopy) for the probability of laryngeal mass via an online survey. The intraclass correlation coefficient (ICC) estimated interrater and intrarater reliability. Diagnostic performance metrics were calculated. A linear mixed effects model examined the impact of expertise and pathology on ratings.

RESULTS

Forty clinicians (21 experts and 19 nonexperts) evaluated 344 voice samples. Experts outperformed nonexperts, with a higher area under the curve (70% vs 61%), sensitivity (49% vs 36%), and specificity (83% vs 77%) (all comparisons p < .05). Interrater reliability was fair for experts and poor for nonexperts (ICC: 0.48 vs 0.34), while intrarater reliability was excellent and good, respectively (ICC: 0.9 and 0.6). The main effects of expertise and underlying pathology were significant in the linear model (p < .001).

CONCLUSION

Clinicians demonstrate inadequate performance screening for laryngeal mass from voice to use auditory perception for dysphonia triage. Experts' superior performance indicates that there is acoustic information in a voice that may be utilized to detect laryngeal mass based on voice.

Implementing a “Distance Traveled” Question to Improve Resident Diversity: Process and Feasibility

Increasing diversity in the physician workforce is important to improving racial and ethnic disparities in health outcomes in the United States. We describe the implementation of a “distance traveled” question (DTQ) in our residency application process. For the 2021-2022 cycle, all applicants to the University of Washington otolaryngology residency program were allowed to complete an optional DTQ. Responses were shared with the application review committee. Following the distribution of interview invites, an anonymous survey was sent to all faculty reviewers. The response rate was 26 of 36 (72%). Among respondents, 20 (77%) felt that the DTQ helped them learn something new about the applicant, and 19 (73%) reported that the DTQ influenced their decision making about the applicant. Thus, a DTQ may provide faculty with new and influential information regarding residency applicants.

Racial and Ethnic Differences in Resident Selection in 11 Specialties, 2013-2018

This study compares the racial and ethnic representation of applicants and matched residents from competitive US medical and surgical specialty programs between 2013 and 2018.

Evidence of Specialty-Specific Gender Disparities in Resident Recruitment and Selection

BACKGROUND

Specialty-specific gender disparities are multifactorial, yet one area that is lacking from this discussion is the impact of recruitment and selection.

OBJECTIVE

Customized data reports were utilized to compare trends in the gender representation of applicants and residents within 11 surgical and medical specialties between 2013 and 2018.

METHODS

Applicant data was obtained from the Electronic Residency Application Service (ERAS) and resident data from the Accreditation Council for Graduate Medical Education (ACGME). Eleven specialties with the highest number of applications per applicant were included (dermatology, emergency medicine, general surgery, neurological surgery, obstetrics and gynecology [OB/GYN], orthopedic surgery, otolaryngology, plastic surgery, radiation oncology, radiology, urology). A Cochran-Armitage trend test assessed for changes in the proportion of females within the total applicant group and the corresponding matched resident group. A t test was utilized to compare the mean proportion of females for ERAS and ACGME data.

RESULTS

Otolaryngology, plastic surgery, radiation oncology, and urology had no significant changes over the study period. Dermatology, general surgery, and orthopedic surgery demonstrated increased gender diversity in applicants over time, while OB/GYN demonstrated decreased gender diversity. General surgery and neurological surgery showed increased gender diversity in resident representation over time. Emergency medicine and radiology had increased gender diversity, and OB/GYN had decreased gender diversity in matched residents compared to applicants.

CONCLUSIONS

Our findings provide baseline data, but also illustrate evident gaps in our understanding and attempts to improve gender diversity. A multifaceted approach to obtaining and assessing data from all stages of residency recruitment and selection is necessary to support these efforts.

Computer-Aided Rhinoplasty Using a Novel "navigated" Nasal Osteotomy Technique: A Pilot Study

OBJECTIVE

To describe the surgical technique of navigation-guided nasal osteotomies and assess feasibility of this technique for treating complex nasal bone deformities in reconstructive rhinoplasty.

METHODS

A retrospective chart review was performed in order to identify patients who underwent computer-aided rhinoplasty from August 2014 to February 2017. Inclusion criteria were nasal bone deformities on computed-tomography (CT) that correlated with specific nasal complaints. All patients underwent computer-aided rhinoplasty with navigation-guided nasal osteotomies using a standard navigation system. Osteotomies were performed using real-time visualization on the navigation screen. Additional soft tissue procedures were performed as needed. Medical records were reviewed for presenting symptoms, radiologic and operative findings, and postoperative course. Cosmetic outcomes were subjectively based on patients' standard 6-view photo-documentation from pre- and post-operative timepoints.

RESULTS

Twenty-one patients were included in the study; 8 were revision cases and 3 had mild-to-moderate hemifacial microsomia. Fifteen were completely closed procedures. No cases were opened because of inadequate visualization or difficulty accessing bony pathology. Mean (range) follow up was 98.6 (6-559) days. There were no intra-operative complications, unplanned admissions or re-admissions, or iatrogenic cosmetic complications (ie, "inverted V" or "saddle nose" deformities). Two patients required revision. One was after suffering nasal trauma within 4 weeks of initial rhinoplasty. The second underwent further correction of a deformity that required a costochondral graft. Both experienced good final results.

CONCLUSIONS

Computer-aided rhinoplasty is safe and feasible for treating complex nasal deformities using standard navigation systems.

A Novel Curriculum for Medical Student Training in LGBTQ Healthcare: A Regional Pathway Experience

BACKGROUND

Lesbian, gay, bisexual, transgender, and queer (LGBTQ) individuals face considerable health disparities, often due to a lack of LGBTQ-competent care. Such disparities and lack of access to informed care are even more staggering in rural settings. As the state medical school for the Washington, Wyoming, Alaska, Montana, and Idaho (WWAMI) region, the University of Washington School of Medicine (UWSOM) is in a unique position to train future physicians to provide healthcare that meets the needs of LGBTQ patients both regionally and nationally.

OBJECTIVE

To describe our methodology of developing a student-driven longitudinal, region-wide curriculum to train medical students to provide high-quality care to LGBTQ patients.

METHODS

A 4-year LGBTQ Health Pathway was developed and implemented as a student-led initiative at the UWSOM. First- and second-year medical students at sites across the WWAMI region are eligible to apply. Accepted Pathway students complete a diverse set of pre-clinical and clinical components: online modules, didactic courses, longitudinal community service/advocacy work, a scholarly project, and a novel clinical clerkship in LGBTQ health developed specifically for this Pathway experience. Students who complete all requirements receive a certification of Pathway completion. This is incorporated into the Medical Student Performance Evaluation as part of residency applications.

RESULTS

The LGBTQ Health Pathway is currently in its fourth year. A total of 43 total students have enrolled, of whom 37.3% are based in the WWAMI region outside of Seattle. Pathway students have completed a variety of scholarly projects on LGBTQ topics, and over 1000 hours of community service/advocacy. The first cohort of 8 students graduated with a certificate of Pathway completion in spring 2020.

CONCLUSIONS

The LGBTQ Health Pathway at UWSOM is a novel education program for motivated medical students across the 5-state WWAMI region. The diverse milestones, longitudinal nature of the program, focus on rural communities, and opportunities for student leadership are all strengths and unique aspects of this program. The Pathway curriculum and methodology described here serve as a model for student involvement and leadership in medical education. This program enables medical students to enhance their training in the care of LGBTQ patients and provides a unique educational opportunity for future physicians who strive to better serve LGBTQ populations.

Does Attending Surgeon Presence at the Preinduction Briefing Improve Operating Room Efficiency?

OBJECTIVE

To examine if attending surgeon presence at the preinduction briefing is associated with a shorter time to incision.

STUDY DESIGN

Retrospective cohort study and survey.

SETTING

Tertiary academic medical center.

SUBJECTS AND METHODS

A retrospective cohort study was conducted of 22,857 operations by 141 attending surgeons across 12 specialties between August 3, 2016, and June 21, 2018. The independent variable was attending surgeon presence at the preinduction briefing. Linear regression models compared time from room entry to incision overall, by service line, and by surgeon. We hypothesized a shorter time to incision when the attending surgeon was present and a larger effect for cases with complex surgical equipment or positioning. A survey was administered to evaluate attending surgeons' perceptions of the briefing, with a response rate of 68% (64 of 94 attending surgeons).

RESULTS

Cases for which the attending surgeon was present at the preinduction briefing had a statistically significant yet operationally minor reduction in mean time to incision when compared with cases when the attending surgeon was absent. After covariate adjustment, the mean time to incision was associated with an efficiency gain of 1.8 ± 0.5 minutes (mean ± SD; P < .001). There were no statistically significant differences in the subgroups of complex surgical equipment and complex positioning or in secondary analysis comparing service lines. The surgeon was the strongest confounding variable. Survey results demonstrated mild support: 55% of attending surgeons highly prioritized attending the preinduction briefing.

CONCLUSION

Attending surgeon presence at the preinduction briefing has only a minor effect on efficiency as measured by time to incision.

A Computer Simulation Model to Analyze the Application Process for Competitive Residency Programs

BACKGROUND

The residency match process for competitive specialties hinders programs' ability to holistically review applications.

OBJECTIVE

A computer simulation model of the residency application process was created to test the hypotheses that (1) it is advantageous to medical students to apply to the maximum number of programs under the current system, and (2) including a medical student's residency program preferences at the beginning of the application process improves the efficiency of the system for applicants and programs as quantified by the number of interview invitations received.

METHODS

The study was conducted in 2016 using 2014 Otolaryngology Match data. A computer model was created to perform simulations for multiple scenarios to test the hypotheses. Students were assigned scores representing easy and hard metrics and program preferences, simulating a mixture of individual student preference and general program popularity.

RESULTS

We modeled a system of 99 otolaryngology residency programs with 292 residency spots and 460 student applicants. While it was individually advantageous for an applicant to apply to the maximum number of programs, this led to a poor result for the majority of students when all applicants undertook the strategy. The number of interview invitations improved for most applicants when preference was revealed.

CONCLUSIONS

Offering applicants an option to provide program preference improves the practical number of interview invitations. This enables programs to review applicants holistically-instead of using single parameters such as United States Medical Licensing Examination scores-which facilitates a selection of applicants who will be successful in residency.

Variation in the representation of human anatomy within digital resources: Implications for data integration

Clinical informatics makes use of anatomical representation-particularly in the form of anatomical terms. But differences and ambiguities in naming anatomical structures and partitioning the body can complicate efforts to interlink anatomical resources and integrate clinical data. To better understand differences in representations of human anatomy, we compare five digital resources: a formal ontology, a terminology, and three 3D graphics applications. Because the graphics applications offer explicit representation of the boundaries and partitions of anatomical structures, they reveal the differences in modeling of anatomy that may not be apparent through text-based representations. The variations in these resources allow us to categorize differences in representations of anatomy and to highlight the importance of this topic in the context of clinical informatics.

Anatomical Region Segmentation for Objective Surgical Skill Assessment with Operating Room Motion Data

Background  Most existing objective surgical motion analysis schemes are limited to structured surgical tasks or recognition of motion patterns for certain categories of surgeries. Analyzing instrument motion data with respect to anatomical structures can break the limit, and an anatomical region segmentation algorithm is required for the analysis. Methods  An atlas was generated by manually segmenting the skull base into nine regions, including left/right anterior/posterior ethmoid sinuses, frontal sinus, left and right maxillary sinuses, nasal airway, and sphenoid sinus. These regions were selected based on anatomical and surgical significance in skull base and sinus surgery. Six features, including left and right eye center, nasofrontal beak, anterior tip of nasal spine, posterior edge of hard palate at midline, and clival body at foramen magnum, were used for alignment. The B-spline deformable registration was adapted to fine tune the registration, and bony boundaries were automatically extracted for final precision improvement. The resultant deformation field was applied to the atlas, and the motion data were clustered according to the deformed atlas. Results  Eight maxillofacial computed tomography scans were used in experiments. One was manually segmented as the atlas. The others were segmented by the proposed method. Motion data were clustered into nine groups for every dataset and outliers were filtered. Conclusions  The proposed algorithm improved the efficiency of motion data clustering and requires limited human interaction in the process. The anatomical region segmentations effectively filtered out the portion of motion data that are out of surgery sites and grouped them according to anatomical similarities.

Evaluation of a Minimally Disruptive Treatment Protocol for Frontal Sinus Fractures

Importance

Despite common goals of frontal sinus fracture treatment (restoring forehead contour and creating a safe sinus), there remains significant variability in evaluation and treatment.

Objective

To describe our experience with a minimally disruptive treatment protocol for the treatment of frontal sinus fractures.

Design, Setting, and Participants

Analysis of prospectively collected data from 2010 through 2015 at a level 1 trauma center. All patients with frontal sinus fractures treated with our protocol from January 2010 to December 2015. Patients with poor follow-up and/or incomplete medical records were excluded from analysis.

Main Outcomes and Measures

Presence of an aerated frontal sinus and aesthetically acceptable forehead contour. Secondary outcome measures were complications related to frontal sinus fractures.

Results

A total of 39 patients were treated under our minimally disruptive protocol, and 25 patients were included in the study; 18 (72%) were male and 7 (28%) were female. Their ages ranged from 6 to 62 years. After review, 22 patients had both clinical and radiographic follow-up. No patients underwent immediate frontal sinus repair. Five of 22 patients underwent surgery for indications other than their frontal sinus fracture: 1 of 5 patients underwent immediate surgical repair due to bilateral LeFort fractures, and 4 of 5 underwent delayed surgery due to nasal polyps (1 patient), scar revision (1 patient), and concomitant LeFort fractures (2 patients). Two of 22 patients (9%) underwent frontal sinus repair after outpatient surveillance due to persistent cerebrospinal fluid leak (1 patient) and orbital roof fracture (1 patient). The remaining 20 patients were treated nonoperatively, and 19 of 20 (95%) had spontaneous improvement in opacification and/or contour deformity. Twelve of 20 patients (60%) had improvement or resolution in both. One patient had ongoing partial opacification and deformity at the 3-month follow-up but was asymptomatic and had bony contour that was aesthetically acceptable to the patient. There were no complications. The median of all follow-up was 3 months.

Conclusions and Relevance

Frontal sinus fractures treated nonoperatively had a high rate of spontaneous ventilation and bony autoreduction with aesthetically acceptable frontal bone remodeling. There were no complications in the nonoperative group. The initial results of this study support further study of the safety and efficacy of a minimally disruptive protocol for frontal sinus fractures.

Level of Evidence

4.

Development of a Novel Markov Chain Model for the Prediction of Head and Neck Squamous Cell Carcinoma Dissemination

Prediction of microscopic tumor spread to regional lymph nodes can assist in radiation planning for cancer treatment. However, it is still challenging to predict tumor spread. In this paper, we present a unique approach to modeling how tumor cells disseminate to form regional metastases. This involves leveraging well established knowledge resources and commonly held notions of how cancer spreads. Using patient data, we utilized our approach to create a model of metastasis for the subset of head and neck squamous cell carcinoma that arises in the mucosa of the lateral tongue. The model was created using a training set extracted from the clinical records of 50 patients with tumors of this type who presented to the University of Washington head and tumor board over a three and half year period. The test sets consist of four case series drawn from the literature.

A Bayesian Network Model of Head and Neck Squamous Cell Carcinoma Incorporating Gene Expression Profiles

Radiation therapy allows precision targeting of certain groups of lymph nodes and is a treatment for metastatic head and neck squamous cell carcinoma. In current practice, there is approximately 15% probability that physicians inadvertently treat healthy tissue or leave the cancerous lymph nodes untreated. The aim of this work is to improve the accuracy of medical decision-making by extending existing predictive models to capture the probabilities of finding cancerous lymph nodes at each of the six image-based surgical neck level using a patient's genetic profile, primary tumor site and tumor size. Our model was trained with publicly available data extracted from the Cancer Genome Atlas (TCGA) and validated against the TCGA dataset both with and without genetic information. Results show that genetic profile data improves model accuracy. These findings suggest that our predictive model may improve the accuracy of clinical decision-making, especially for patients with more advanced metastasis. However, more data is needed to ensure significance of the proposed effects, as well as to improve accuracy of the overall model.

Endothelial and circulating C19MC microRNAs are biomarkers of infantile hemangioma

Infantile hemangioma (IH) is the most common vascular tumor of infancy, and it uniquely regresses in response to oral propranolol. MicroRNAs (miRNAs) have emerged as key regulators of vascular development and are dysregulated in many disease processes, but the role of miRNAs in IH growth has not been investigated. We report expression of C19MC, a primate-specific megacluster of miRNAs expressed in placenta with rare expression in postnatal tissues, in glucose transporter 1-expressing (GLUT-1-expressing) IH endothelial cells and in the plasma of children with IH. Tissue or circulating C19MC miRNAs were not detectable in patients having 9 other types of vascular anomalies or unaffected children, identifying C19MC miRNAs as the first circulating biomarkers of IH. Levels of circulating C19MC miRNAs correlated with IH tumor size and propranolol treatment response, and IH tissue from children treated with propranolol or from children with partially involuted tumors contained lower levels of C19MC miRNAs than untreated, proliferative tumors, implicating C19MC miRNAs as potential drivers of IH pathogenesis. Detection of C19MC miRNAs in the circulation of infants with IH may provide a specific and noninvasive means of IH diagnosis and identification of candidates for propranolol therapy as well as a means to monitor treatment response.

Biological Model Development as an Opportunity to Provide Content Auditing for the Foundational Model of Anatomy Ontology

Constructing a biological model using an established ontology provides a unique opportunity to perform content auditing on the ontology. We built a Markov chain model to study tumor metastasis in the regional lymphatics of patients with head and neck squamous cell carcinoma (HNSCC). The model attempts to determine regions with high likelihood for metastasis, which guides surgeons and radiation oncologists in selecting the boundaries of treatment. To achieve consistent anatomical relationships, the nodes in our model are populated using lymphatic objects extracted from the Foundational Model of Anatomy (FMA) ontology. During this process, we discovered several classes of inconsistencies in the lymphatic representations within the FMA. We were able to use this model building opportunity to audit the entities and connections in this region of interest (ROI). We found five subclasses of errors that are computationally detectable and resolvable, one subclass of errors that is computationally detectable but unresolvable, requiring the assistance of a content expert, and also errors of content, which cannot be detected through computational means. Mathematical descriptions of detectable errors along with expert review were used to discover inconsistencies and suggest concepts for addition and removal. Out of 106 organ and organ parts in the ROI, 8 unique entities were affected, leading to the suggestion of 30 concepts for addition and 4 for removal. Out of 27 lymphatic chain instances, 23 were found to have errors, with a total of 32 concepts suggested for addition and 15 concepts for removal. These content corrections are necessary for the accurate functioning of the FMA and provide benefits for future research and educational uses.

Early introduction of clinical skills improves medical student comfort at the start of third-year clerkships

BACKGROUND

To determine whether introducing clinical skills during the second year of medical school, via a competency-based College system approach, improves comfort level for medical students entering third-year clinical rotations.

METHOD

From 2003-2005, two cohorts of third-year medical students at the University of Washington were surveyed on their comfort level in the categories of history taking, physical examination, communication, and patient care.

RESULTS

The cohort of students exposed to the College system reported a statistically significant greater comfort level in half of the measured areas, and in at least one area within each general category. No area of study showed a statistically significant decline.

CONCLUSION

A competency-based College system improves medical student comfort in core clinical skills at the start of the third year curriculum.

A sequence-oriented comparison of gene expression measurements across different hybridization-based technologies

Over the last decade, gene expression microarrays have had a profound impact on biomedical research. The diversity of platforms and analytical methods available to researchers have made the comparison of data from multiple platforms challenging. In this study, we describe a framework for comparisons across platforms and laboratories. We have attempted to include nearly all the available commercial and 'in-house' platforms. Using probe sequences matched at the exon level improved consistency of measurements across the different microarray platforms compared to annotation-based matches. Generally, consistency was good for highly expressed genes, and variable for genes with lower expression values as confirmed by quantitative real-time (QRT)-PCR. Concordance of measurements was higher between laboratories on the same platform than across platforms. We demonstrate that, after stringent preprocessing, commercial arrays were more consistent than in-house arrays, and by most measures, one-dye platforms were more consistent than two-dye platforms.

Porous High-Density Polyethylene for Orbital Reconstruction

OBJECTIVE

To determine the safety and efficacy of using porous high-density polyethylene (PHDPE) in the repair of orbital defects.

DESIGN

Retrospective case series.

SETTING

Academic tertiary care trauma center. Patients One hundred seventy patients with orbital defects requiring surgical repair. Intervention Orbital defect repair with PHDPE. Main Outcome Measure Our review documents surgical results and complications associated with the use of PHDPE.

RESULTS

There was a 6.4% complication rate associated with the use of PHDPE. The infection rate was 1.8%. The persistent orbital malposition rate was 3.5%. The extrusion rate was 0%.

CONCLUSIONS

This report represents the largest case series in the literature using PHDPE for orbital reconstructions. The use of PHDPE resulted in a low complication rate and excellent functional and cosmetic reconstructive results. Because of our success with the use of PHDPE, we have changed our clinical practice to minimize the use of autologous graft material, thereby eliminating donor site morbidity in cases involving orbital reconstruction.

A Genomic Predictor of Oral Squamous Cell Carcinoma

OBJECTIVES/HYPOTHESIS

The objective was to identify a genomic profile that predicts the likelihood of oral squamous cell carcinoma compared with normal oral mucosa in unknown tissue samples.

STUDY DESIGN

Using a training set of tissue samples that were histologically classified as oral squamous cell carcinoma or normal mucosa, the authors used principal component analysis to develop a genomic predictor for oral squamous cell carcinoma. On a separate test set of unclassified samples, the authors used the predictor to classify the samples, then evaluated the performance of the predictor using histological diagnosis.

METHODS

The authors used a data set consisting of messenger RNA extracted from 29 oral squamous cell carcinoma and 19 normal oral mucosa tissue samples and hybridized to Affymetrix oligonucleotide microarrays containing probe sets for 7070 genes and expressed sequence tags. The samples were divided into a training set of 15 oral squamous cell carcinoma and 10 normal samples and a test set consisting of the remaining samples. Using principal component analysis on the training set, the authors found a composite gene expression vector (principal component vector), which they used to compute likelihood ratios for oral squamous cell carcinoma on the test set. By calculating the contribution of each gene to the principal component vector, the authors identified genes with the greatest predictive value.

RESULTS

Using the likelihood ratio, the authors correctly classified all 23 samples in the test set as either oral squamous cell carcinoma or normal. The authors found that many of the most predictive genes are known to be markers of squamous cell carcinoma or normal mucosa.

CONCLUSION

Principal component analysis can be used with genomic microarray data to correctly predict the presence of oral squamous cell carcinoma in unknown tissue samples.

Deciphering gene expression profiles generated from DNA microarrays and their applications in oral medicine

Genome-wide monitoring of gene expression profiles using DNA microarrays provides a unique approach to exploring the biological processes underlying oral diseases and disorders by providing a comprehensive survey of a cell's or tissue's transcriptional mapping. This revolutionary technology allows for the simultaneous assessment of the transcription levels of tens of thousands of genes, and of their relative expression between normal and diseased cells. As microarray data analysis evolves, there is a widespread hope that microarrays will significantly impact our ability to explore the genetic changes associated with disease etiology and development, ultimately leading to the discovery of new biomarkers for disease diagnosis and prognosis prediction as well as new therapeutic tools. The goal of this manuscript is to review 2 of the most commonly used microarray technologies, provide an overview of data analyses involved in a typical microarray experiment, and comment upon the application of microarrays to oral medicine.

A log likelihood predictor for genomic classification of oral cancer using principle component analysis for feature selection

DNA microarrays are powerful tools for exploring gene expression and predicting disease state. However, since the number of variables (genes) typically exceeds the number of samples (tissue specimens), many potentially spurious genes may be selected for a predictor function. Principle component analysis (PCA) can greatly reduce the high-dimensional microarray data space while retaining most of the inherent variability. We propose a methodology that uses PCA to identify a predictor vector between two mutually exclusive and collectively exhaustive classes. By projecting the training set upon this vector a distribution of projections can be computed for each class. A log-likelihood ratio is then calculated for class membership. We used this methodology to classify 48 biopsy specimens as either oral squamous cell carcinoma or normal oral mucosa using oligonucleotide microarrays. The system was trained using a set of half the samples, and correctly predicted the membership of the other half. The three most highly positively and three most highly negative predictive genes were all keratins that are known markers of squamous cell carcinoma.

Microarrays and clinical dentistry

BACKGROUND

The Human Genome Project, or HGP, has inspired a great deal of exciting biology recently by enabling the development of new technologies that will be essential for understanding the different types of abnormalities in diseases related to the oral cavity.

LITERATURE REVIEWED

The authors review current literature pertaining to the advanced microarray technologies arising from the HGP and how they can contribute to dentistry. This technology has become a standard tool for monitoring activities of genes at both academic and pharmaceutical research institutions.

RESULTS

With the availability of the DNA sequences for the entire human genome, attention now is focused on understanding various diseases at the genome level. Deciphering the molecular behavior of genetically encoded proteins is crucial to obtaining a more comprehensive picture of disease processes. Important progress has been made using microarrays, which have been shown to be effective in identifying gene expression patterns and variations that correlate with cellular development, physiology and function. Arrays can be used to classify tissue samples accurately based on molecular profiles and to select candidate genes related to a number of cancers, including oral cancer. This type of oral genetic approach will aid in the understanding of disease progression, thus improving diagnosis and treatment for patients.

CLINICAL IMPLICATIONS

Microarrays hold much promise for the analysis of diseases in the oral cavity. As the technology evolves, dentists may see these tools as screening tests for better managing patients' dental care.

Functional relationships between gene pairs in oral squamous cell carcinoma

We developed a novel method for the discovery of functional relationships between pairs of genes based on gene expression profiles generated from microarrays. This approach examines all possible pairs of genes and identifies those in which the relationship between the two genes changes in different diseases or conditions. In contrast to previous methods that have focused on differentially expressed genes, this method attempts to find changes in the correlation between genes. These changes may be indicative of the functional relationships related to a disease mechanism. We demonstrate the utility of this approach by applying it to an oral squamous cell carcinoma (OSCC) microarray data set. Our results suggest new directions for future experimental investigations.

Gene expression profiling by DNA microarrays and its application to dental research

DNA microarray technology has been used for genome-wide gene expression studies that incorporate molecular genetics and computer science skills on massive levels. The technology permits the simultaneous analysis of tens of thousands of genes for the purposes of gene discovery, disease diagnosis. improved drug development, and therapeutics tailored to specific disease processes.

OBJECTIVE

In this review, the two most common microarray technologies and their potential application to dental research will be discussed. The authors review current articles pertaining to the technologies and analysis of mRNA expression using DNA micro-arrays and its application to dental research. Since many genes contribute to normal functioning, research efforts are moving from the search for a disease specific gene to the understanding of the biochemical and molecular functioning of a variety of genes and how complicated networks of interaction can lead to a disease state, such as oral cancer. With the incorporation of DNA micro-array based research, we can look forward to more accurate diagnosis and surgical treatment/drug-delivery therapy based on an individual patient's genetic profile.