2016 Abstracts - Clinical Sciences - Faculty

CS 1: A Novel Bilateral Branching Pattern of the Axillary Artery and Its Clinical Implications

Kristen Giefer, Anthony Olinger, Kyle Busch, and Ashley Olson

Kansas City University

Introduction: This report describes a novel bilateral branching pattern of the axillary artery. The axillary artery classically produces six branches including the superior thoracic artery, followed by the thoracoacromial trunk, the lateral thoracic artery, the subscapular artery, and the posterior and anterior circumflex humeral arteries. RESOURCES: Upon dissection of the axillary region, an anomalous branching pattern of the axillary artery was discovered bilaterally on a 93 year old male specimen. DESCRIPTION: Just distal to the first rib, the axillary artery produced a large trunk supplying five of the classic axillary branches. On the right, the thoracoacromial trunk arose first, followed by the supreme and lateral thoracic arteries. On the left, the supreme thoracic artery arose at the same level as the thoracoacromial trunk, followed by the lateral thoracic artery. Bilaterally, the trunk then continued as the subscapular arteryproducing its terminal branches, the circumflex scapular and thoracodorsal arteries, but terminated as the posterior circumflex humeral artery. The axillary artery produced only one of its classic branches, the anterior circumflex humeral artery, distal to its anomalous trunk. SIGNIFICANCE: Surgeons should be aware of the potential for this type of anomalous branching when utilizing a transaxillary approach for treatment of venous thoracic outlet syndrome and breast augmentation, and when performing infraclavicular incisions for first rib removal. Surgical biopsies and tissue excision of axillary lymphatics due to breast cancer metastases and the use of certain axillary branches as recipient arteries during autogenous breast tissue reconstruction also place these anomalous branches at risk for injury. 

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CS 2: Relating Patterns of Positional Behavior in Bearded Capuchin Monkeys to Substrate Use and Anatomical Form

Kristin Wright1, Louis Biondi2, Dorothy Fragaszy3, and Patricia Izar2

1Kansas City University, 2University of Sao Paulo, 3University of Georgia

Understanding the positional behavior (posture and locomotion) of nonhuman primate species and how it relates to habitat use provides important insights about the selective factors that have driven the evolution of anatomical form and function in the Order Primates. In particular, living primate species that adopt bipedal behaviors in association with daily activity patterns, foraging, and terrestrial habitat use provide analogues in which to test hypotheses concerned with the evolution of bipedalism in humans. Here we present subset of data from a year-long study of the positional behavior of bearded capuchin monkeys (Sapajus libidinosus), a non-human primate species that regularly demonstrates bipedal behaviors and is known to use stone tools during foraging and food processing (Fragaszy et al. 2004; Visalberghi et al., 2007). Sixteen adult bearded capuchins (9 females and 7 males) from two habituated groups were observed from October 2008 through September 2009. A total of 10,244 observations were recorded. Our results indicate that bearded capuchins spend 58% of their daily activity budget foraging for food, 16% traveling, and 13% of their time in other behaviors such as social behavior. Overall, bearded capuchins spend 28% of their day on terrestrial substrates, mostly engaged in foraging activities (73% of all terrestrial observations). Although primarily quadrupedal, our findings corroborate previous work highlighting bipedal activity in this species and we discuss the prevalence of this behavior in the context of overall activity pattern, substrate use, and previous anatomical findings (Wright et al., 2015). 

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CS 4: What Do Pediatric Residency Program Directors Expect From Incoming Pediatric Interns?

Anne VanGarsse and Ramon Newman

Kansas City University

Background: It is not known what skills or knowledge pediatric program directors desire new residents to possess when they begin residency. A review of the literature reveals that Internal Medicine program directors have been specifically and comprehensively surveyed regarding their desires for skills and knowledge of incoming internal medicine residents. Family medicine, obstetrics/gynecology and surgery program directors have also been surveyed regarding their desires for incoming residents. To our knowledge, however, there has never been a large scale survey of pediatric program directors as to their expectations of incoming interns. Additionally, the existing information pertaining to expectations held by program directors for incoming interns is from surveys performed before the publication of the Core Entrustable Professional Activities (EPAs) for entering residency, as put forth by the AAMC in 2014. To our knowledge, program directors have not been surveyed as to whether the EPAs meet their needs for qualities expected in incoming residents. After IRB approval, a survey was submitted to pediatric program directors from pediatric residency programs identified from ACGME and AOA websites. Pediatric program directors were asked to rate on a 5-point Likert scale 20 different skills/knowledge sets collected from the 13 published AAMC EPAs as well as the 7 most highly rated items from the IM PD survey. Program directors unanimously rated communicating in a culturally sensitive manner and gathering a history and physical highest, followed equally by providing an oral presentation of a clinical encounter, knowing when to seek assistance, and effective communication with nurse/nurse triage. 

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2016 Abstracts - Clinical Sciences - Faculty

CS 5: Determining a Correlation Between Left Atrium Area and Os of the Left Atrial Auricle Diameter to Aid in Care Plan of Patients with Persistent Atrial Fibrillation in the Prevention of Stroke with a ‘Left Atrial Appendage Closure Device’

Amanda Osterloh1, Stanley Wiggins2, and Anthony Olinger3

1University of Kansas Medical Center, 2Mercy Clinic Cardiology & Clinical Cardiac Electrophysiology, 3Kansas City University

Determining a correlation between the size of the left atrium (LA) and the left atrial auricular os (LAAO) would be beneficial in treating patients with persistent atrial fibrillation (AF) in the prevention of stroke. Medical device companies have developed ‘left atrial appendage closure devices’ (LAACD) designed to prevent stroke in patients with persistent AF. These devices are deployed over the LAAO, where emboli develop. In finding the proposed anatomical correlation, clinicians could determine the appropriate sized LAACD preoperatively. This could aid in determining if further intervention may be indicated after use of the closure device, given the increase in the size of the LA over time due to AF. The LA was measured from anterior to posterior atrial walls and from right to left pulmonary vein. The inside diameter of the LAAO was measured. Area of the LA was calculated and correlated to the size of the LAAO. There was a positive correlation between the area of the LA and the diameter of the LAAO, such that as the area of the LA increased so too did the diameter of the LAAO. Given these findings clinicians can determine preoperatively the appropriate size of a LAACD to ensure a positive outcome. Also, clinicians can predict that as the LA enlarges over time due to the pathogenesis of atrial fibrillation, so too will the LAAO, despite the closure device. Repeat echocardiograms are indicated to monitor the stability of the device and determine if interventions are necessary to prevent emboli from dislodging.

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CS 6: Integrating Surgical Skills into Pre-Clinical Years of Medical School

Haley Stewart1, Barth Wright1, Vicki Sharma1, Christopher Surek2, Robert Stephens1, Julie Vircks2, and Erich Wessel2

1Kansas City University, 2University of Kansas Medical Center

Introduction: Current literature indicates that medical students lack competency and understanding of basic surgical principles when entering clinical rotations. Studies show early surgical exposure can improve student competence and confidence upon entering surgical clerkships. The purpose of this study is to create early exposure to routine operative procedures, surgical anatomy and dissection planes before entering surgical clerkships. METHODS: Twenty- one pre-clinical medical students interested in pursuing surgical careers were selected to participate in this study. The course consisted of 3 educational presentations followed by a surgical procedure. The procedures, led by surgical residents, consisted of a skin cancer resection with adjacent tissue flap closure, hysterectomy, and cholecystectomy. All students completed a pre- and post-study competency exam of surgical anatomy and surveys to determine confidence levels with surgical skills. Basic statistics were utilized to evaluate the data. RESULTS: An overall 51% improvement in knowledge of surgical anatomy was shown in the competency exam. In the pre-survey 90% (n=19) reported lack of confidence in suturing and preparedness for clerkships. In the post-survey 95% (n=20) reported confidence in these areas. Also, in the pre- survey 76% (n=16) felt unprepared to handle surgical tools while assisting in surgery. However, post-survey all students reported confidence. All students indicated that the experience reinforced the surgical relevance of gross anatomy and encouraged incorporation of the study into the curriculum. CONCLUSION: This study improved confidence in pre-clinical medical students’ understanding of surgical anatomy and basic surgical skills. This may enhance learning and improve performance during surgical clerkships. 

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CS 7: Localization and Preservation of the Lobular Branch of the Great Auricular Nerve in Rhytidectomy Procedures

Vicki Sharma1, Christopher Surek2, Robert Stephens1, and Barth Wright1

1Kansas City University, 2University of Kansas Medical Center

Background: Current literature suggests preserving the lobular branch of the great auricular nerve (GAN) has greater impact on sensory function at the auricle than preservation of the posterior branch during rhytidectomy. However, no methodology exists to efficiently and accurately determine the topographic location of the lobular branch. OBJECTIVE: This study will describe the branching characteristics of the lobular branch and algorithmic surface markings to assist surgeons in preservation of this nerve during rhytidectomy flap elevation. METHODS: The lobular branch was dissected in 50 cadaveric necks. Measurements were taken from the lobular branch to conchal cartilage, tragus, and antitragus. The anterior branch was measured to its SMAS insertion and the posterior branch was measured to the mastoid process. McKinney’s point was marked and the GAN diameter was recorded. Branching pattern and location of branches within the Ozturk 30-degree angle were documented. Basic statistics were performed. RESULTS: The lobular branch was present in all specimens and distributed to 3 regions. In 85% of specimens, the lobular branch resided directly inferior to the antitragus and in the remaining specimens it was located directly inferior to the tragus. Pre-operative markings consisting of two vertical lines from the tragus and antitragus to McKinney’s point can be used to outline the predicated location of the lobular branch. CONCLUSIONS: This study delineates the location of the lobular branch of the GAN. We translate these findings into a quick and simple intraoperative marking which can assist surgeons in avoiding lobular branch injury during rhytidectomy dissection.

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CS 8: Assessing the Relationship between Levator Ani Nerve Length and Pelvic Floor Dysfunction

Kristen Giefer, Ashley Olson, and Barth Wright

Kansas City University

Introduction: This report describes the existence of a correlation between levator ani nerve (LAN) length and the transverse diameter of the pelvic outlet. As the distance between ischial tuberosities (ITs) increases, LAN length also increases. RESOURCES: The LAN was found via gross dissection after hemisection of the pelvis was performed on 24 female cadavers. Nerve measurements were taken from their point of origin from the pelvic wall to their insertion into the pelvic floor musculature. The ITs were stripped of their soft tissue attachments and the hemisected pelves were re-approximated to measure the intertuberous distance. DESCRIPTION: The LAN received contributions from S3 and S4 anterior rami. It coursed forward anteromedially and then disappeared as it pierced the iliococcygeus muscle deep to the pelvic parietal fascia. The portion of nerve that was not covered by muscle, but lying just deep to the pelvic parietal fascia, was accepted as LAN length. The intertuberous distance was taken as the diameter between the inferomedial-most aspect of the ITs. The correlation between IT breadth and LAN length was found to be significant (p < 0.05). SIGNIFICANCE: This correlation is significant for obstetricians and gynecologists, and surgeons who should be aware that a longer LAN length may increase the risk for stretch injury during vaginal birth, or transection during gynecologic and rectal excision procedures. Thus, consideration of an increased intertuberous distance may help to inform decisions about the birthing process and other pelvic surgical procedures that may lessen the risk for developing pelvic floor dysfunction.

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CS 9: Complications and Retrieval Rates of Inferior Vena Cava Filters, a Single-Center Retrospective Study

Ankit Mohla1, Nathaniel Parker1, Scott Kujath2, Rebecca Thomas2, and Robert Carter2

1Kansas City University, 2North Kansas City Hospital, Midwest Aortic and Vascular Institute

Objective: While anticoagulation remains the primary prophylactic method for the treatment of venous thromboembolisms, deep vein thrombosis, and pulmonary embolisms, the use of inferior vena cava (IVC) filters has increased significantly in the last two decades. Recent studies have suggested that there is an increased frequency of complications associated with all brands of retrievable filters when compared to permanent filters (9% vs 3.0%; P < .0001). These complications are subcategorized into thrombotic and device-related complications. We aimed to further delineate the complication rates and types between retrievable and permanent filters when used chronically to treat and/or prevent VTE symptomatology and fatal progressions. Methods: Electronic medical records of all patients who received an IVC filter between January 1st 2001- July 1st, 2015 were reviewed. Analysis included a comprehensive comparison of the patients who received a retrievable and permanent filter. Results/Conclusion: We identified a total of 591 filters placed. 345 of these filters were of the retrievable type and 220 were of the permanent type. Patient complications were categorized when causing thrombosis, tilting, migration, vena caval perforation, fracture, and subsequent pulmonary embolism formation after filter placement. The most common complications were thrombosed filter (10), perforation (6) and tilt (6). Statistical analysis found a higher complication rate for retrievable filter types. However, our data suggests that the overall complication and mortality associated with filter placement to be lower than what is currently noted in literature. This suggests that filter placement can be a viable intervention in those needing extra protection against fatal pulmonary emboli.

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CS 10: Propensity for Nerve Impairment: An Assessment of Nerve Proximity During Cortical Button Guidewire Placement for Distal Biceps Brachii Tendon Reattachment

Taylor Brown, Barth Wright, Anthony Olinger, and Matthew Daggett

Kansas City University

Introduction: The endoscopic cortical button repair of the distal biceps tendon following rupture yields a superior rate of return of function and strength compared to previous methods; however, the risk of nerve complications remains high. The objective of this study was to assess the distance from three nerves (posterior interosseous nerve (PIN), superficial radial nerve (SRN), and the median nerve (MN)) to a guidewire placed 30° in the ulnar direction in the coronal plane during reattachment of the tendon. METHODS. In 50 cadaveric specimens, the forearm was removed at the distal end of the radial tuberosity and imaging software was used to establish a 30° reference angle on the transverse cross-section, a safe angle determined from previous studies. The distance between the three nerves and the reference angle was measured and a safe angle for the guidewire was confirmed based on the greatest average distance from the nerves of interest. Results: From the 30° reference angle, the mean distances to the MN, SRN, and PIN were 5.56 mm, 10.34 mm, and 13.67 mm, respectively. From these measurements, the optimal safe angle was determined to be the midpoint between the MN and SRN. The average angle from the axis which bisects the nerves was 42.58°. CONCLUSIONS. We recommend a change in drilling angle from the original 30° to 45° in the ulnar direction while the arm is in maximal supination. This angle optimizes the safety the PIN, MN, and SRN during open or endoscopic EndoButton repairs of distal biceps tendon ruptures.

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CS 11: Using Anatomical Landmark to Avoid Phrenic Nerve Injury During Balloon-Based Procedures in Atrial Fibrillation Patients

Nicolina (Taylor) Smith1, Larry Segars1, Travis Kauffman2, and Anthony Olinger1

1Kansas City University, 2University of Missouri Kansas City

Introduction: Atrial fibrillation (AF) is an arrhythmia that effects upwards of 2.7 million Americans. AF must be treated because it can lead to a 4-5 fold increased risk of having a stroke. The American College of Cardiology/American Heart Association guidelines for the treatment of drug refractory and symptomatic paroxysmal AF denote catheter ablation as gold standard care. The newest ablation treatment, cryoballoon, uses a cold balloon tip. The cryoballoon allows the ablation to occur with minimal damage to the endothelium of the pulmonary veins. The biggest risk factor associated with the cryoballoon ablation is phrenic nerve injury (PNI). Individuals have a 0.48- 11% incidence of PNI, depending on the anatomy of the individual, location of the ablation, and amount of energy used. Many methods are currently used to identify and try to preserve the phrenic nerve (PN) during the cryoballoon ablation, however none of them are considered gold standard. A physician commonly uses two to three different techniques to try to keep the PN safe. METHODS: Using 30 cadaveric specimens we were able to take measurements of where the PN is in relationship to the right superior pulmonary vein (RSPV) antrum as well as the lateral border of the 6th thoracic vertebrae (T6). Results: The average RPN-RSPV orifice distance was 9.6mm. The average RPN-T6 distance was 30.6mm. CONCLUSION: Using T6 as a landmark, which can be viewed under fluoroscopy during the procedure, we can now make an approximate map for the physician to locate where the PN lies. 

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CS 12: Examination of the Intercostal Nerve and Branch Points: A Cadaveric Study

Penelope Burikas, Danielle Solomon, Ian Bowers, and Anthony Olinger

Kansas Ciy University

Thoracentesis can result in neuralgia as a result of severing the branches of the intercostal nerve. The present study aimed to investigate a safe zone as a better entry points for procedures. Human cadavers were selected for the study. With the cadavers in the supine position, each intercostal space was dissected out with careful examination of the intercostal nerves and branches. Any nerve branch seen or nerve that crossed midline was pinned so that measurements could be taken. Calculations were performed to identify a safe zone for each intercostal space. The measurements were reviewed comparing each intercostal space in order to recommend the safest intercostal space. After thorough dissection of each intercostal space, the safest zone for instrument insertion was found to be in spaces 4 and 7, 120 mm from midline on the right side. Based on this cadaveric study, Intercostal spaces 4 and 7, 120 mm from midline on the right side resulted in infrequent severing of any branches of the intercostal nerve, and would be a more suitable location for instrument placement in thoracentesis and VATS procedures.

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CS 13: Characterization of the Superior Vena Cava for Radiographic Confirmation of Central Venous Catheter Placement

Travis Kauffman1, Amanda Osterloh2, and Anthony Olinger3

1University of Missouri Kansas City, 2Univeristy of Kansas Medical Center, 3Kansas City University

The placement of central venous catheters (CVCs) is a procedure in the hospital setting, and chest radiographs are used to confirm the CVC is placed correctly. Failure to place CVCs in the correct position can result in failure of the apparatus and complications. When viewing a chest radiograph, radiologist use landmarks to determine the location of the CVC. This study characterizes the superior vena cava in relation to the posterior ribs and carina in order to assist with accurate interpretation of CVC placement. This study explores the common locations of the azygos vein tributary (AT). Data was collected from 38 embalmed cadavers. The posterior rib level of the brachiocephalic-superior vena caval junction (BCSVCJ), AT and cavoatrial junction (CAJ) were recorded using the anterior-posterior plane to simulate a portable chest radiograph. The distance of the BCSVCJ, AT and CAJ from the carina was recorded. The BCSVCJ was located at the level of the posterior 3rd rib and at or before the posterior 3rd intercostal space (ICS). The AT was located at the posterior 5th ICS and at or between the 4th and 5th posterior rib. The CAJ was located at the 5th ICS and in 27/38 specimens at or before the level of the 6th posterior rib. The relationships seen between the structures studied can be used to confirm proper placement of CVCs. The carina is a common landmark already used, but may be difficult to see. In these cases, the posterior ribs serve as reliable landmarks.

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CS 14: Characterization of the Inferior Vena Cava to Improve IVC Filter Placement and Longevity

Ashley Olson, Kristen Giefer, Kenna Schnarr, and Anthony Olinger

Kansas City University

Introduction: Malformations of the inferior vena cava (IVC) can cause stenosis and turbulent flow, which increase deep venous thrombosis (DVT) risk. Because angulation also produces turbulent flow it is reasonable to predict this would lead to an increased risk of DVT. Such risk indicates IVC filter placement. Complications like tilt, which occurs when the filter no longer resides in the center of the IVC, are common. This study aims to characterize the IVC to improve IVC filter placement and longevity. MATERIALS AND METHODS: The IVCs of 76 cadavers were accessed using gross dissection. The positions of the hepatic, suprarenal, renal, right gonadal, and first lumbar (segmental) veins were recorded. The distances between the hepatic and renal veins and between the renal veins and IVC bifurcation were measured. The angle of the IVC in relation to the long axis of the body (angulation) was recorded. Linear regressions were conducted between all data and between genders. Results: No correlation between branching distances and IVC angulation was found. IVC branching patterns have little to no variation. Overall, men have greater and more frequent angulation than women. CONCLUSIONS: Our finding of no correlation between branching distances and IVC angulation as well as little to no variation in branching pattern allows physicians to disregard these variables as predictors for angulation and thus risk factors for DVT. However, males’ propensity to exhibit greater and more frequent angulation should be considered when placing an IVC filter due to possible increased risk of DVT.

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CS 15: The Anterolateral Ligament: An Anatomic Study on Gender Differences

Joseph Granite, Barth Wright, Anthony Olinger, Kyle Busch, and Matthew Daggett

Kansas City University

INTRODUCTION. There are an estimated 100,000-250,000 anterior cruciate ligament (ACL) injuries annually, with female athletes two to eight times more likely to suffer an ACL injury than their male counterparts. Reasons for this gender discrepancy have been previously investigated, with several different factors being linked to this increased prevalence. ACL reconstruction provides reproducible and satisfactory results in both sexes; however, some patients may continue to have rotational instability of the knee after ACL reconstruction as confirmed by a positive “pivot-shift” test. Recent investigations have validated the existence of the anterolateral ligament (ALL) and its contributions to rotational stability of the knee. The purpose of our paper is to define any gender differences in the anatomical structure of the ALL. METHODS. 36 embalmed cadaveric specimens were used. The iliotibial band was reflected distally to its insertion onto Gerdy’s tubercle. The ALL was identified with its fibers originating in close proximity to the femoral lateral epicondyle and stretching distally toward its insertion onto the tibia between Gerdy’s tubercle and the fibular head. Using a digital caliper measurements were taken of the ALL. SUMMARY: The ALL was identified on all 36 cadaveric knees that were dissected. We found that the thickness of the ALL was 55% smaller in the female cadavers when compared to the male cadavers. CONCLUSIONS. We believe this gender related difference in the thickness of the ALL could be another intrinsic risk factor that contributes to the propensity of a higher ACL rupture rate in female athletes.

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CS 16: Pterygospinous and Pterygoalar Ligament Presence as an Etiology of Trigeminal Neuralgia

Kyle Busch and Anthony Olinger

Kansas City University

INTRODUCTION. The characteristics of the pterygoalar and pterygospinous ligaments in the infratemporal fossa have been extensively documented in studies using dried crania and, to a much lesser extent, cadavers. Researchers have hypothesized about the potential role these ligaments may play in the entrapment of nearby neurovasculature resulting in facial neuralgias, more specifically trigeminal neuralgia. The purpose of this cadaveric study was to characterize the ligaments’ prevalence, their relation to the local neurovasculature, and determine whether or not the presence of a ligament was associated with neuralgia symptoms using patient history. METHODS. Measurements were taken by 2 individuals on 54 cadavers. Our specimens were divided into three groups: no ligament, pterygoalar ligament, or pterygospinous ligament. A living relative of those cadavers with a pterygospinous ligament was then contacted and asked to complete a trigeminal neuralgia questionnaire pertaining to their loved one. SUMMARY. Pterygospinous ligaments were found in 11 cadavers (20%), 3 of which were ossified. No pterygoalar ligaments were present in our cadaver population. Of the individuals contacted, none indicated that their loved one had ever suffered from trigeminal neuralgia or symptoms relating to facial neuralgia pathology. CONCLUSIONS. Presence of a pterygospinous ligament did not cause trigeminal neuralgia in our population. The pterygospinous and pterygoalar ligaments will continue to draw attention for their significance in anesthesia and surgical procedures. More research needs to be done to identify an etiology of trigeminal neuralgia in those refractory to traditional medical interventions.

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CS 17: Relating Aortic Annulus to the Femoral and Subclavian Arteries

Justin Oveyssi, Ravi Piryani, and Anthony Olinger

Kansas City University

INTRODUCTION: Trans-thoracic aortic valve implantation is a surgical technique that is used for replacing aortic valves. Replacement valves may be delivered through femoral artery, subclavian artery, or through the thoracic wall. One contraindication is an aortic annulus diameter greater than 27mm or less than 18mm. This study seeks to determine how often the aortic annulus diameter falls outside of this recommended range. We are looking to see if there is a correlation between the diameters of the aortic annulus, femoral, or subclavian arteries. RESOURCES: The diameter of the aortic annulus was measured. Diameters of subclavian arteries were also measured bilaterally at level of the first rib. Femoral artery diameters were measured bilaterally two inches down from the ilioinguinal ligament. Diameters of aortic annuli as well as femoral and subclavian arteries were compared. We determined if there was a positive correlation between any of the measurements. SIGNIFICANCE: Establishing whether or not there is a positive correlation between measurements may have surgical implications. Positive correlation between femoral artery diameter and aortic annulus diameter may indicate a preference for one form of TAVI over another. Results of this study assist surgeons in minimizing risk. Conclusion: Positive correlation between the diameter of the aortic annulus and the diameter of the subclavian arteries measured. No statistically significant correlation identified between the diameters of the femoral arteries and the aortic annulus. The diameter of the aortic annulus fell outside of the recommended range for suitable TAVI candidacy in 29.2% of the cadavers.

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CS 18: Cranial Evidence for Orthograde Postures In New World Monkeys

Maaheen Ahmed and Kristin Wright

Kansas City University

Our understanding of the relationship between anatomy and positional behavior (posture and locomotion) in primates has typically focused on analyses of features of the postcranial skeleton. However, a few studies have examined changes in cranial features such as orientation of the orbits and basicranial flexion and how these may relate to posture and/or locomotion (Strait and Ross 1999, Lieberman et al. 2000). Additionally, at least one previous study has shown that strepsirrhine primates (lemurs and lorises) that exhibit more orthograde postures will have a more anteriorly positioned foramen magnum than those that are non-orthograde (Russo & Kirk, 2013). Here we test the hypothesis that for New World primates (platyrrhines) that exhibit more orthograde postures while stationary or in motion, the position of the foramen magnum will be more anterior than for those that are not known to exhibit these behaviors. Controlling for differences in body size, we examined 4 basicranial features relative to the basion line, using ratios for molar, palatal, bicarotid chord and temporal fossa lengths among a sample of 17 Primate species from 15 genera (total specimens, n=109). For three of the four comparisons, our findings generally support the prediction that primates which adopt orthograde postures will exhibit a more anteriorly positioned foramen magnum. The lack of support from the temporal fossa ratio is likely attributable to the presence of masticatory features unique to a given clade. The results of this study increase support for the utility of using basicranial features as indicators of bipedal behaviors in primates.

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CS 19: Classic Radiographic Signs Revisited

Larry Mathias1, Melissa Rosado-de-Christenson2, Santiago Martínez-Jimènez2, and Susan Gutschow3

1Kansas City University, 2Saint Lukes Hospital of Kansas City, 3University of Missouri Kansas City

Background Information: Radiographic interpretation is challenging and often relies on identification of signs that allow anatomic localization of an abnormality and determination of its possible etiology. Although these signs were described decades ago by pioneers in chest radiology (Felson, Golden), they are often misunderstood and incorrectly employed. We review frequently misinterpreted radiographic signs using a case-based approach and correlative CT images, graphic illustrations and differential diagnostic considerations and present the correct semantics and significance of each sign. Educational Goals: Chest radiographs are the initial imaging study used to evaluate patients with thoracic complaints. Once an abnormality is identified, it must be localized to a thoracic compartment in order to suggest the diagnosis or formulate an appropriate differential diagnosis. Classic radiographic signs remain extremely useful as they provide critical diagnostic information. After reviewing this exhibit, the learner will understand the imaging appearance and significance of each classic radiographic sign and should be able to formulate a focused differential diagnosis. Key Imaging Findings: Proper use of the cervicothoracic sign, thoracoabdominal sign, hilum overlay and hilum convergence signs, lateralization of the aortopulmonary reflection, doughnut sign, and finally the S-sign of Golden allows for accurate deciphering of otherwise difficult to interpret images. Conclusion: The classic radiographic signs have stood the test of time and remain instrumental in determining the location and etiology of radiographic abnormalities. However, these signs are often poorly understood. Understanding these signs allows physicians to render accurate radiographic diagnoses and suggest the most appropriate next imaging or management step.

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CS 20: The Internal Cartotid Artery, Occulomotor, Trochlear, Ophthalmic, Maxillary and Abducens Nerves in Relation to the Cavernous Sinus

Mandalyn Kautz and Anthony Olinger

Kansas City University

INTRODUCTION: Previous research suggests the occulomotor, trochlear, ophthalmic, maxillary and abducens nerves (cranial nerves III, IV, V1, V2, and VI) and the cavernous portion of the internal carotid artery (ICA) pass through the cavernous sinus (CS) with different positional relationships between each of these structures. Based on the disparity of anatomical representations portraying the CS, the objective of the study was to clarify relationships of the major structures contained within. RESOURCES: The craniums of 20 female and 23 male totaling 43 adult embalmed cadavers were utilized for dissection. The aforementioned cranial nerves were identified along with the ICA after removing the pituitary gland from the sella turcica and dissecting medial to lateral through the CS. DESCRIPTION: Occulomotor, trochlear, ophthalmic, and maxillary nerves were found within leptomeninges in descending order superomedial to inferolateral in the lateral wall while the ICA and abducens nerve were located within the CS independent of the arachnoidal and dural sheath. It is important to note the abducens nerve was found inferolateral relative to the ICA often loosely adhered to the vessel. SIGNIFICANCE: Due to the position of the abducens nerve, it may be more vulnerable to injury in comparison to the nerves located within the lateral wall when the CS is compromised. The findings of the study may be applied when considering neoplasms, infection, microsurgery, sella enlargement and other clinical pathology which warrant an understanding of the gross anatomy of the cavernous sinus.

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CS 21: Characterization of the Clavicular Deltoid Tubercle by Gender for Use as a Palpable Landmark

Julia Ronecker, Brandon Geosling, and Anthony Olinger

Kansas City University

INTRODUCTION: Subclavian vein cannulation is a common procedure to gain central venous access in patients. Several landmarks exist to determine site of entry and angle, but require additional patient manipulation and anatomical measurements. Recent studies suggest that the clavicular deltoid tubercle would simplify this procedure because of its proximity to the vein and ability to be palpated easily. This study aims to characterize the location of the deltoid tubercle on the clavicle and determine its prevalence in the general population for use as a surgical landmark. RESOURCES: A total of 68 right and left clavicles (30 male, 38 female) were used from 47 embalmed cadavers. Skin, muscle, and tissue were removed from the clavicle for tubercle access. The tubercle was characterized by its length (mm), its distance from the sternal and acromial ends to the tubercle’s center (mm), and its ability to be palpated in both sexes. DESCRIPTION: The clavicles revealed statistically similar deltoid tubercles (12.46mm +/- 5.37mm for males, 13.09mm +/- 4.50mm for females). Tubercles were also similar distances from the sternal and acromial ends in both sexes. The majority of tubercles (80%) were palpable, and the ability to be palpated was dependent on tubercle size (palpable tubercle 14.22mm +/- 4.36mm and non-palpable tubercle 6.94mm +/- 1.55mm). SIGNIFICANCE: Because this structure can be palpated easily, is located in the same relative location on the clavicle in both males and females, and requires no additional measurements to perform central venous access, the deltoid tubercle represents a prevalent, reliable surgical landmark.

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CS 22: Introduction of Clinical Specialty Tracks in the Third Year: A Pilot Program

Lauren Branham1, Natalie Lynch1, and John Dougherty2

1Kansas City University, 2Touro University Nevada

Recruiting and retaining preceptors for clinical education is a continuous challenge in an increasingly competitive environment. Focused honors tracks in family medicine, internal medicine, pediatrics, behavioral health, women’s health, general surgery, and orthopedic surgery during the clinical third year are a way to match likeminded students and preceptors. Integration of focused clinical tracks for high-performing students is an innovative approach to increase experiential exposure in their preferred discipline, thus improving the students’ likelihood to match in their desired specialty. To gauge interest in the newly-created track programs, an iClicker survey was administered to second year students prior to ranking rotation sites. Sixty percent were favorable to the idea of tracks. A maximum of 10 students was set for each track with a minimum 3.25 GPA and 40 students were enrolled. Midway through the track year, a focus group of track students was conducted to receive feedback. All participants said they would either “absolutely” or “likely” remain in their track and apply to that specialty for residency. Also, honors track students achieved “honors” designation on 45.5 percent of NBME subject exams taken, compared to the traditional track students at 22.6 percent. Positive byproducts of this model include increased satisfaction of students and preceptors by matching both parties’ interests, expanded clinical opportunities for students, and a sustained network of high-quality preceptors. Furthermore, honors track students have received higher COMLEX Level 1 and NBME subject exam scores than their traditional track counterparts. Pilot program students will be followed through the 2017 residency match.

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