The distal femur trochlear groove appears to compensate for tibial deformity but not femoral deformity in an investigation of five-hundred and seventy-nine cadaveric skeletons.

BACKGROUND: The etiology of patellofemoral disorders is multifactorial. Preoperative patellofemoral anatomy evaluation is of great importance in patients undergoing surgery for patellofemoral disorders. Although anatomical risk factors of patellofemoral disorders have been thoroughly investigated in clinical and radiological studies, there are sparse data regarding the association between trochlear dysplasia with other anatomical parameters. This study sought to explore those associations using a large osteological collection. METHODS: Five-hundred and seventy-nine cadaveric skeletons were obtained from the Hamann-Todd osteological collection. Mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), femoral version, tibial torsion, lateral position of the tibial tubercle, and femoral length were modeled as predictors of medial and lateral flange height of the distal femur trochlea at various degrees of knee flexion. RESULTS: The average age and standard deviation for the 1158 lower extremities analyzed was 55.9 ± 10.2 years. There were 500 males (86%) and 79 females. Increasing MPTA or tibial valgus predicted increasing lateral femoral flange height at 0, 30, and 50 degrees of knee flexion [(standardized beta 0.111, p = 0.01), (standardized beta 0.129, p < 0.001), and (standardized beta 0.186, p < 0.001), respectively]. Increasing internal tibial torsion predicted increased medial flange height at 30 and 50° [(standardized beta - 0.114, p = 0.006), (standardized beta - 0.108, p = 0.006), respectively]. Increased femoral retroversion predicted increasing lateral flange height at 0 and 30 degrees [(standardized beta - 0.105, p = 0.005), (standardized beta - 0.098, p = 0.004), respectively]. CONCLUSIONS: To maintain the equilibrium necessary for effective patellar tracking, the depth of trochlear groove appears to effectively compensate for some of the anatomical parameters of the proximal tibia associated with patellofemoral disorders, and appears to be less influenced by femoral alignment. The clinical relevance of these findings warrants further investigation, and emphasizes the importance of carefully assessing the lower limb alignment in the management of patellofemoral disorders.

Experimental validation of finite element simulation of a new custom-designed fixation plate to treat mandibular angle fracture.

BACKGROUND: The objective of the study was to validate biomechanical characteristics of a 3D-printed, novel-designated fixation plate for treating mandibular angle fracture, and compare it with two commonly used fixation plates by finite element (FE) simulations and experimental testing. METHODS: A 3D virtual mandible was created from a patient's CT images as the master model. A custom-designed plate and two commonly used fixation plates were reconstructed onto the master model for FE simulations. Modeling of angle fracture, simulation of muscles of mastication, and defining of boundary conditions were integrated into the theoretical model. Strain levels during different loading conditions were analyzed using a finite element method (FEM). For mechanical test design, samples of the virtual mandible with angle fracture and the custom-designed fixation plates were printed using selective laser sintering (SLS) and selective laser melting (SLM) printing methods. Experimental data were collected from a testing platform with attached strain gauges to the mandible and the plates at different 10 locations during mechanical tests. Simulation of muscle forces and temporomandibular joint conditions were built into the physical models to improve the accuracy of clinical conditions. The experimental vs the theoretical data collected at the 10 locations were compared, and the correlation coefficient was calculated. RESULTS: The results show that use of the novel-designated fixation plate has significant mechanical advantages compared to the two commonly used fixation plates. The results of measured strains at each location show a very high correlation between the physical model and the virtual mandible of their biomechanical behaviors under simulated occlusal loading conditions when treating angle fracture of the mandible. CONCLUSIONS: Based on the results from our study, we validate the accuracy of our computational model which allows us to use it for future clinical applications under more sophisticated biomechanical simulations and testing.

Is There Value in Radiology Reads for Pediatric Supracondylar Fractures in the Outpatient Clinic?

BACKGROUND: Increased health care costs have driven assessment of value of common practices. The Joint Commission mandates the dual interpretation of musculoskeletal radiographs by radiologists and orthopedic surgeons in hospital-based clinic settings. However, the value of this practice has come under question. The purpose of this study was to investigate whether radiologist interpretations change orthopedists' management during follow-up of pediatric supracondylar humerus fractures. METHODS: A retrospective review was performed of pediatric elbow fractures at a single institution from January 2012 to December 2015. Patients with supracondylar humerus fractures and at least one clinic follow-up were included. For each radiograph, the orthopedic surgeon and radiologist interpretations were reviewed and a determination was made as to whether the radiologist interpretation affected management of the patient. In films with disagreement of displacement, Baumann angle and posterior displacement based on Gartland classification with Wilkins and Leitch modifications were measured. Timing of final radiologist and orthopedic interpretations were also assessed. Finally, billing charges of radiologist interpretations were assessed. RESULTS: There were 441 pediatric supracondylar humerus fracture patients included in this study. All 441 patients had at least 1 clinic follow-up, 397 patients had at least 2 clinic follow-ups, and 123 patients had at least 3 clinic follow-ups, with a total of 716 elbow radiographs obtained. There were 17 cases (2.4%) where orthopedics and radiologist final interpretations disagreed regarding fracture displacement. In no cases did radiologist interpretations change orthopedic management. Radiographs that orthopedics interpreted as displaced were more likely to be posteriorly displaced (80.0% vs. 0.0%; P=0.002). However there was no difference in Baumann angle (P=0.125). Of the 716 films included, 28 radiologist interpretations were performed the day after the clinic visit (4%). Excluding these cases, there was an average of 57±3 minutes between radiograph acquisition and final interpretation. There were 352 cases where final orthopedic note filing time was documented, and 32% of these notes were finalized prior to the final radiologist interpretations. The total charges of radiologist interpretations was $18,772. CONCLUSIONS: The results of this study suggest that dual-interpretation of radiographs obtained in the follow-up clinic setting does not add value in management of pediatric supracondylar humerus fractures. LEVEL OF EVIDENCE: Level IV-case series.

Pediatric Supracondylar Humerus Fractures: AAOS Appropriate Use Criteria Versus Actual Management at a Pediatric Level 1 Trauma Center.

OBJECTIVES: The purpose of this study was to characterize management of supracondylar humerus fractures (SCHFs) at a level 1 trauma center and identify factors contributing to divergence in management from American Academy of Orthopedic Surgeons (AAOS) the Appropriate Use Criteria (AUC) recommendations. METHODS: A query revealed 556 patients with diagnoses of SCHF between 2013 and 2015 at a pediatric level 1 trauma center. Patients were excluded if they were younger than 2 years of age, older than 12 years of age, were polytrauma patients, or if there was not sufficient clinical or radiographic documentation, resulting in 449 patients. Urgent/emergent intervention was defined as surgery within 8 hours of presentation. Binomial logistic regression assessed whether various factors predicted operative versus nonoperative management. RESULTS: Operative management was undertaken in 0/208 (0%) type I fractures, 61/106 (57.0%) type II fractures, and 135/135 (100%) type III fractures. Comparison with AUC recommendations revealed disagreement in 31% (138/449) of cases. Among 449 patients, 44 were treated nonoperatively despite AUC recommendations for operative treatment. All 44 of these patients were type II SCHFs managed nonoperatively. There were no definitive cases of malalignment or loss of alignment in these nonoperative cases. Factors predictive of operative management were anterior humeral line not intersecting the capitellum (odds ratio, 200; P<0.001) and increasing age (odds ratio, 1.53; P=0.024). The AUC more frequently recommended urgent/emergent operative intervention (148/449, 33.0%) than was performed at our pediatric level 1 trauma center (50/449, 11.1%). The majority of this disagreement (94/98, 95.9%) consisted of uncomplicated type III SCHF treated operatively in >8 hours. None of these patients developed compartment syndrome or required an open reduction. CONCLUSIONS: The American Academy of Orthopedic Surgeons AUC recommended operative and urgent/emergent intervention more frequently than was performed at a level 1 pediatric trauma center. Patient age and alignment of the anterior humeral line with the capitellum, though not specifically addressed in the AUC, were most predictive of operative versus nonoperative management at our institution.

Plantar and medial heel pain: diagnosis and management.

Heel pain is commonly encountered in orthopaedic practice. Establishing an accurate diagnosis is critical, but it can be challenging due to the complex regional anatomy. Subacute and chronic plantar and medial heel pain are most frequently the result of repetitive microtrauma or compression of neurologic structures, such as plantar fasciitis, heel pad atrophy, Baxter nerve entrapment, calcaneal stress fracture, and tarsal tunnel syndrome. Most causes of inferior heel pain can be successfully managed nonsurgically. Surgical intervention is reserved for patients who do not respond to nonsurgical measures. Although corticosteroid injections have a role in the management of select diagnoses, they should be used with caution.

3D-printed porous condylar prosthesis for temporomandibular joint replacement: Design and biomechanical analysis.

BACKGROUND: Customized prosthetic joint replacements have crucial applications in severe temporomandibular joint problems, and the combined use of porous titanium scaffold is a potential method to rehabilitate the patients. OBJECTIVE: The objective of the study was to develop a design method to obtain a titanium alloy porous condylar prosthesis with good function and esthetic outcomes for mandibular reconstruction. METHODS: A 3D virtual mandibular model was created from CBCT data. A condylar defect model was subsequently created by virtual condylectomy on the initial mandibular model. The segmented condylar defect model was reconstructed by either solid or porous condyle with a fixation plate. The porous condyle was created by a density-driven modeling scheme with an inhomogeneous tetrahedral lattice structure. The porous condyle, supporting fixation plate, and screw locations were topologically optimized. Biomechanical behaviors of porous and solid condylar prostheses made of Ti-6Al-4V alloy were compared. Finite element analysis (FEA) was used to evaluate maximum stress distribution on both prostheses and the remaining mandibular ramus. RESULTS: The FEA results showed levels of maximum stresses were 6.6%, 36.4% and 47.8% less for the porous model compared to the solid model for LCI, LRM, and LBM loading conditions. Compared to the solid prosthesis, the porous prosthesis had a weight reduction of 57.7% and the volume of porosity of the porous condyle was 65% after the topological optimization process. CONCLUSIONS: A custom-made porous condylar prosthesis with fixation plate was designed in this study. The 3D printed Ti-6Al-4V porous condylar prosthesis had reduced weight and effective modulus of elasticity close to that of cortical bone. The.

Emergency Department Utilization Is Low After Outpatient Elective Rotator Cuff Repair.

INTRODUCTION: The purpose of this study was to establish emergency department (ED) utilization rate and reasons for presentation to the ED after outpatient rotator cuff repair (RCR) and determine preoperative predictors for these ED visits. METHODS: Patients who underwent outpatient RCR between 2014 and 2015 were retrospectively evaluated using the New York and Florida State Databases. The primary outcome was all-cause 7- and 30-day ED utilization rates. Reasons for presentation to the ED were recorded and stratified. Univariate and multivariate analyses were done to identify independent predictors of ED utilization. RESULTS: The 7- and 30-day ED visit rates were 3.2% and 5.0%, respectively. The most common cause for an ED visit after outpatient RCR at 7- and 30-days postoperatively were postoperative pain (29.0%) and GI complaints (16.3%), respectively. African American race (odds ratio [OD], 1.69; P < 0.001), Hispanic race (OD, 1.47; P = 0.005), and comorbid diagnoses of hypertension (OD, 1.51; P < 0.001), diabetes (OD, 1.58; P < 0.001), and/or schizophrenia (OD, 5.14; P < 0.001) were independent risk factors for an ED visit at up to 30 days postoperatively. Those with Medicare (OD, 2.01; P < 0.001) or Medicaid (OD, 2.61; P < 0.001) were more than twice as likely to present to the ED within 30 days than those with private health insurance. DISCUSSION: ED utilization after outpatient RCR is uncommon with postoperative pain as the most common chief concern for ED visits within the first 7 days and GI issues as the most common reason for ED encounters at up to 30 days postoperatively. Hypertension, diabetes, renal failure, liver disease, rheumatologic diseases, schizophrenia, depression, and Medicare and Medicaid insurance were independent predictors of ED encounters at up to 30 days postoperatively. Procedures done at freestanding surgery centers were protective against ED utilization. LEVEL OF EVIDENCE: Level III, Retrospective Cohort.

Comparing Plastic Surgeon Versus Orthopedic Surgeon Outcomes Following Distal Upper Extremity Amputations: A Study of the National Surgical Quality Improvement Program (NSQIP) Database.

BACKGROUND: Both plastic and orthopedic surgeons manage care for urgent/emergent hand conditions. It is unclear if surgeon specialty affects patient outcomes of these cases. The purpose of this study was to evaluate differences in 30-day perioperative outcomes between plastic and orthopedic surgeons following distal upper extremity amputations. METHODS: Patients who underwent distal upper extremity amputations between 2005 and 2016 were identified within the National Surgical Quality Improvement Program (NSQIP) database using Current Procedural Terminology (CPT) codes. Differences in operative procedures, patient demographics, patient comorbidities, and 30-day perioperative complications were compared between orthopedic and plastic surgeons by univariate analysis. A Bonferroni correction was applied to account for multiple comparisons of complications. RESULTS: A total of 1583 cases met inclusion criteria. Orthopedic surgeons performed 981 cases (62.0%) and plastic surgeons performed 602 cases (38.0%). Finger amputations comprised the majority of procedures for both orthopedic and plastic surgeons (95.5% and 94.4%, respectively). Orthopedic surgeons had a lower operative time (41.7 ± 36.2 minutes vs 47.1 ± 40.9 minutes, P = .008). There were no differences in proportion of emergency surgery, inpatients, or wound class. There were no differences in age, gender, or body mass index. The most common indications for amputation were trauma, gangrene, and osteomyelitis. There were no differences between surgical specialties in 18 30-day perioperative complications assessed, including death, reoperation, surgical site infection, or wound dehiscence. CONCLUSIONS: Plastic and orthopedic surgeons achieved equivalent outcomes comparing 30-day perioperative complications following upper extremity amputations. These results support that both orthopedic and plastic surgeons provide similar quality distal upper extremity amputation care.

HISTORIQUE: Tant les plasticiens que les chirurgiens orthopédiques prennent en charge les cas d'affections urgentes ou d'extrême urgence touchant les mains. On ne sait pas si la spécialité chirurgicale a une incidence sur le pronostic des patients atteints de ces problèmes. La présente étude visait à évaluer les différences entre les résultats périopératoires des plasticiens et des chirurgiens orthopédiques 30 jours après des amputations distales des extrémités supérieures. MÉTHODOLOGIE: Les patients qui ont subi une amputation distale des extrémités supérieures entre 2005 et 2016 ont été extraits de la base de données du Programme national d'amélioration de la qualité des soins chirurgicaux (NSQIP) à l'aide des codes du Catalogue des actes médicaux (CPT). Au moyen d'une analyse univariée, les chercheurs ont comparé les différences entre les interventions opératoires effectuées par les chirurgiens orthopédiques et les plasticiens, les caractéristiques démographiques des patients, leurs autres affections et leurs complications périopératoires au bout de 30 jours. Ils ont utilisé une correction de Bonferroni pour tenir compte de multiples comparaisons entre les complications. RÉSULTATS: Au total, 1 583 cas respectaient les critères d'inclusion. Les chirurgiens orthopédiques ont opéré 981 cas (62,0 %) et les plasticiens, 602 cas (38,0 %). Les amputations des doigts représentaient la majorité des interventions effectuées par les chirurgiens orthopédiques et les plasticiens (95,5 % et 94,4 % respectivement). Les opérations pratiquées par les chirurgiens orthopédiques étaient plus courtes (41,7 ± 36,2 minutes par rapport à 47,1 ± 40,9 minutes, p = 0,008). Il n'y avait pas de différence quant à la proportion d'opérations d'urgence, de patients hospitalisés ou de catégories de plaies ni pour ce qui est de l'âge, du genre et de l'indice de masse corporelle. Les principales indications d'amputation étaient des traumatismes, la gangrène et l'ostéomyélite. Il n'y avait pas de différence entre les spécialités chirurgicales lors de l'évaluation des complications périopératoires au bout de 18 et 30 jours, y compris les décès, les réopérations, l'infection au foyer des infections et la déhiscence des plaies. CONCLUSIONS: Les plasticiens et les chirurgiens orthopédiques ont obtenu des résultats équivalents si l'on comparait les complications périopératoires après des amputations des extrémités supérieures au bout de 30 jours. Selon ces résultats, à la fois les chirurgiens orthopédiques et les plasticiens fournissent des soins de qualité semblables lors d'amputations distales des membres supérieurs.

A Comparison of 30-Day Perioperative Complications for Open Operative Care of Distal Upper-Extremity Fractures Treated by Orthopedic Versus Plastic Surgeons: A Study of the National Surgical Quality Improvement (NSQIP) Database.

Purpose: To determine whether surgeon specialty affects complications after open operative care of distal upper-extremity fractures. Methods: We performed a retrospective cross-sectional study using the American College of Surgeons National Surgical Quality Improvement Database from 2005 to 2016. Patients were included if they received open operative treatment by an orthopedic or a plastic surgeon for distal radius/ulna, carpal, metacarpal, or phalangeal fracture. Univariate analysis and multivariable analysis of perioperative complications were performed to identify differences between the 2 specialties. Major complications assessed were 30-day reoperation and mortality. We also assessed transfusion, thromboembolic, surgical site infections, cardiac, pulmonary, and renal complications. Results: A total of 20,512 patients were included. Most cases performed by orthopedic surgeons (71.2%) were for distal radius/ulna fractures, whereas the majority of cases performed by plastic surgeons were for metacarpal (41.0%) and phalangeal (37.9%) fractures. No difference was identified in most perioperative complications between specialties. Plastic surgeons had a higher incidence of surgical site infections (1.2% vs 0.5%) on univariate analysis. However, when controlling for variables such as patient demographics and comorbidities in multivariable analysis, surgical specialty was not significantly associated with surgical site infection. Rather, surgery on phalangeal bones (adjusted odds ratio [aOR] = 2.745; 95% confidence interval [CI], 1.559-4.833), higher wound class (wound class 3 aOR = 3.630; 95% CI, 2.003-6.577), and smoking (aOR = 1.970; 95% CI, 1.279-3.032) were independent risk factors for surgical site infection. Plastic surgeons were found to operate on proportionally more smokers, patients with higher wound class, and phalangeal fractures (37.9% of all fracture cases) compared with orthopedic surgeons. Conclusions: Orthopedic and plastic surgeons achieve equivalent outcomes from a safety perspective after open operative treatment of upper-extremity fractures in terms of mortality and 30-day reoperation, which suggests that both specialties can safely perform call-related operative upper-extremity fracture care. Plastic surgeons operated on more smokers, patients with higher wound class, and phalangeal fractures, all of which were associated with increased incidence of surgical site infection, revealing differences in practice composition from their orthopedic colleagues. Type of study/level of evidence: Therapeutic III.

Emergency Department Utilization After Outpatient Hand Surgery.

BACKGROUND: The purpose of this study was to identify the utilization rate and most common reasons for presentation to the emergency department (ED) after elective outpatient hand surgery and to determine preoperative risk factors for these ED visits. METHODS: Patients who underwent elective hand surgery at an ambulatory surgery center between 2014 and 2015 were retrospectively evaluated using the New York and Florida State Databases. The primary outcome was all-cause 7- and 30-day ED utilization rates. Reasons for presentation to the ED were recorded and manually stratified. Bivariate and multivariate analyses were performed to identify independent predictors of ED utilization. RESULTS: From 2014 to 2015, 212,506 procedures were identified; the 7- and 30-day ED visit rates were 1.8% and 4.4%, respectively. Postoperative pain was the most common cause of an ED visit after outpatient hand surgery at 7 days (25.4%) and 30 days (16.1%) postoperatively. Overall, 98% of patients presenting to the ED for postoperative pain were subsequently discharged home. After controlling for confounding, comorbid congestive heart failure, chronic lung disease, diabetes, renal failure, schizophrenia, and depression were independent risk factors for an ED visit at up to 30 days postoperatively. Those with Medicare insurance were 94% more likely to present to the ED within 30 days than those with private health insurance, whereas those with Medicaid were more than three times as likely to present to the ED as those with private insurance. DISCUSSION: ED utilization after outpatient hand surgery is low, with postoperative pain being the most common cause of an ED visit at all time points. Nearly 98% of patients presenting to the ED for postoperative pain are subsequently discharged home. LEVEL OF EVIDENCE: Level III, Retrospective Cohort.

The detection of alkaline phosphatase using an electrochemical biosensor in a single-step approach.

A one-step, single use, disposable Alkaline Phosphatase (ALP) biosensor has been developed. It is based on the detection of phenol produced by an ALP enzymatic reaction. It can operate at 25 °C in a pH 10 medium. It measures ALP of 0-300 IU/L. The permissible concentrations of glucose, ascorbic acid and urea without interference are 10 mM/L, 5 mg/L and 400 mg/L, respectively. Experimental results are compared to those obtained by spectrophotometric measurements in bovine serum. Excellent linearity between the biosensor outputs and the ALP concentrations exists. The agreement between the measurements of this biosensor and the spectrophotometer is also outstanding.

Analysis of biomechanical behavior of 3D printed mandibular graft with porous scaffold structure designed by topological optimization.

BACKGROUND: Our long-term goal is to design and manufacture a customized graft with porous scaffold structure for repairing large mandibular defects using topological optimization and 3D printing technology. The purpose of this study is to characterize the mechanical behavior of 3D printed anisotropic scaffolds as bone analogs by fused deposition modeling (FDM). METHODS: Cone beam computed tomography (CBCT) images were used to reconstruct a 3D mandible and finite element models. A virtual sectioned-block of the mandible was used as the control group and the trabecular portion of the block was modified by topological optimization methods as experimental groups. FDM (FDM) printed samples at 0, 45 and 90 degrees with Poly-lactic acid (PLA) material under a three-point bending test. Finite element analysis was also used to validate the data obtained from the physical model tests. RESULTS: The ultimate load, yield load, failure deflection, yield deflection, stress, strain distribution, and porosity of scaffold structures were compared. The results show that the topological optimized graft had the best mechanical properties. CONCLUSIONS: The results from mechanical tests on physical models and numerical simulations from this study show a great potential for topological optimization and 3D printing technology to be served in design and rapidly manufacturing of artificial porous grafts.

Biomechanical behavior of mandibles reconstructed with fibular grafts at different vertical positions using finite element method.

BACKGROUND: For large mandibular defects, surgical reconstruction using microvascular fibular grafts has advantages over other alternatives in terms of blood supply and good quality of grafted bone. However, the fibular segment is usually lower in height than that of the original mandible, meaning that the vertical positioning of the fibular graft is variable, with different biomechanical consequences on the reconstructed mandible. OBJECTIVES: To use finite element method (FEM) to evaluate stress distribution and displacement of a reconstructed mandible versus an intact mandible under occlusal loads. METHODS: A three-dimensional intact edentulous mandibular bone (Model I) and a reconstructed mandible bone with fibular graft were created from CBCT images. Calculation models were generated with fibular bone graft extracted from the reconstructed mandible of identical length placed into a mimicked defect area on the right-hand side of the mandible at three different vertical positions: superior (Model II), intermediate (Model III), and inferior (Model IV). Forces were applied at lower left first molar region and lower left central incisor area. Von Mises stresses and mandibular displacement were calculated as outcome measurements during loadings. RESULTS: Maximum stress and strain within the reconstructed mandible were identified at the posterior border of the graft and the contralateral condyle. Maximum displacement occurred near the interface of fibular graft and anterior segment of the mandible. Stress distribution in the graft under functional loads is much higher than that in the residual mandibular segments from Models II to IV. The combined average maximum stress from anterior and posterior loads is 10.66 times higher in the mandible with inferiorly positioned graft (Model IV), 8.72 times for superior graft (Model II), and 3.68 times for intermediate graft (Model III) than that in the control group (Model I). The worst displacement result during functional loadings was in the group with fibular graft located at the inferior border of the mandible. CONCLUSIONS: The position of fibular graft placed in the surgical resection site has significant effects on the mechanical behavior of the reconstructed mandible. The fibular graft aligned with the inferior border of the mandible, the most common site designated location by clinicians, has the worst effects on the stress distribution and displacement to the mandibular under functional loads. The fibular graft placed at the intermediate location has the best biomechanics and provides favorable condition for subsequent prosthetic reconstruction.

Evaluation of the utility of the Wells score in predicting pulmonary embolism in patients admitted to a spine surgery service.

STUDY DESIGN: A retrospective medical chart review of 4179 patients admitted to the spine surgery service. OBJECTIVE: To evaluate the utility of the Wells score in predicting pulmonary embolism (PE) in patients admitted to a spine surgery service. SUMMARY OF BACKGROUND DATA: The decision to perform computed tomography pulmonary angiography (CTPA) to diagnose PE in patients who have undergone spine surgery requires consideration of multiple factors: false-positive CTPA results may lead to unnecessary anticoagulation treatment, and computed tomography scans are costly and expose patients to ionizing radiation. The Wells score was developed to assign risk categories to patients with suspected PE and thereby indicate the need for CTPA. However, the utility of the Wells score in predicting the likelihood of PE, specifically in spine surgery patients, has not been described to date. We identified all patients who were admitted to the spine surgery service at our institution from January 1, 2001 to December 31, 2011 and underwent CTPA. Each patient's CTPA result was classified as positive or negative for PE, and the reason for ordering the CTPA was recorded. The Wells score was calculated retrospectively for each patient, and risk categories were assigned by using the traditional and alternative interpretations of the Wells score. The reason for the CTPA, the Wells score, and Wells risk category were compared for patients who were classified as being positive or negative for PE. RESULTS: Sixty-six of the 4179 patients who were admitted to the spine surgery service underwent CTPA for suspected PE. Nineteen of the 66 patients (28.8%) were diagnosed with acute PE, and the overall PE rate was 0.45% (19 of 4179 patients). The mean Wells score for patients diagnosed with PE was 5.3, whereas the mean score for the remaining patients was 4.9 (P = 0.793). Neither the traditional nor the alternative interpretation of the Wells score was predictive of PE (P = 0.394 and P = 0.178, respectively). Our study examined the utility of the Wells score in predicting PE in spine surgery patients. CONCLUSION: The results of the CTPA did not show a significant correlation with the Wells score or the reason for the test. Our findings indicate the need to develop a predictive scoring system that assesses the risk of PE and assists in the decision-making process for ordering CTPA in spine surgery patients.

Development of an electrochemical-based aspartate aminotransferase nanoparticle ir-C biosensor for screening of liver diseases.

Aspartate aminotransaminase (AST) is a hepatocelluar enzyme released into the bloodstream when hepatic cells are damaged, resulting in elevated blood levels of AST. A single use, disposable biosensor prototype, composed of catalytic iridium nano-particles dispersed on carbon paste, was developed to detect enzymatically-produced H2O2 in AST-mediated reactions. This biosensor is capable of measuring AST levels in a phosphate buffer and undiluted human serum over the concentration range of 0 to 0.89 µg/mL AST concentration (corresponding to 0-250 UL-1 specific activity). The biosensor operates at relatively low oxidation potential (+0.3 volt (V) versus the printed Ag/AgCl), minimizing any potential chemical interference in human serum. The measurements of AST in human serum using the biosensor compared well with those measured by standard hospital spectrophotometric assays. This Ir-C biosensor may be useful for AST measurements in the clinical environment.

Effect of human beta-defensin-3 on head and neck cancer cell migration using micro-fabricated cell islands.

BACKGROUND: To examine the effect of the natural antimicrobial peptide human ß-defensin-3 (hBD-3), on the migration of a head and neck cancer cell line in vitro using microfabrication and soft-lithographic techniques. METHODS: TR146 cancer cells were seeded in Petri dishes with microfabricated wells for cell migration assays. Total 54 cell islands were used of various shape and size and experimental media type. Cell migration assays were analyzed in six group media: Dulbecco's modified medium (DMEM); DMEM with vascular endothelial growth factor (VEGF); Conditioned media of human embryonic kidney cells (HEK 239) expressing hBD-3 via transfected cloned pcDNA3 as CM/hBD-3; CM/hBD-3+ VEGF; conditioned medium from non-transfected HEK 239 (not expressing hBD-3) as control (CM); and the last group was CM + VEGF. Cell islands were circular or square and varied in size (0.25 mm(2), 0.125 mm(2), and 0.0625 mm(2)). Cell islands were imaged at t=0 h, 3 h, 6 h, and 24 h. RESULTS: The results show cancer cell islands that originally were smaller had higher migration indices. There was no difference of MIs between circular and square cell islands. MIs at the end point were significantly different among the groups except between CM and CM-hBD-3+ VEGF. CONCLUSIONS: VEGF enhanced cancer cell migration. The combination of DMEM and VEGF showed a synergistic effect on this phenomenon of cancer cell migration. Conditioned medium with hBD-3 suppressed cancer cell migration. hBD-3 suppressed VEGF enhancement of TR146 cancer cell migration.

Determination of alanine aminotransferase with an electrochemical nano ir-C biosensor for the screening of liver diseases.

Alanine aminotransaminase (ALT), is an enzyme that normally resides in serum and body tissues, especially in the liver. It is released into the serum as a result of tissue injury; hence the concentration of ALT in the serum may be increased with acute damage to hepatic cells. A single use, disposable biosensor, comprising iridium nano-particle as catalyst dispersed on carbon paste, has been developed for the determination of ALT concentration. The biosensor is based on quantifying H2O2 concentration produced by a serial of ALT enzymatic reactions. It operates well at room temperature in different physiological fluids: phosphate buffer, calf serum and human serum for ALT concentration of 0-544 ng/mL. Experimental results in human serum are compared to those obtained by spectrophotometric assays with excellent agreement. Therefore, the Ir/C biosensor shows good relationship on the dilution of concentrated ALT clinical applications.

Modeling the cumulative genetic risk for multiple sclerosis from genome-wide association data.

BACKGROUND: Multiple sclerosis (MS) is the most common cause of chronic neurologic disability beginning in early to middle adult life. Results from recent genome-wide association studies (GWAS) have substantially lengthened the list of disease loci and provide convincing evidence supporting a multifactorial and polygenic model of inheritance. Nevertheless, the knowledge of MS genetics remains incomplete, with many risk alleles still to be revealed. METHODS: We used a discovery GWAS dataset (8,844 samples, 2,124 cases and 6,720 controls) and a multi-step logistic regression protocol to identify novel genetic associations. The emerging genetic profile included 350 independent markers and was used to calculate and estimate the cumulative genetic risk in an independent validation dataset (3,606 samples). Analysis of covariance (ANCOVA) was implemented to compare clinical characteristics of individuals with various degrees of genetic risk. Gene ontology and pathway enrichment analysis was done using the DAVID functional annotation tool, the GO Tree Machine, and the Pathway-Express profiling tool. RESULTS: In the discovery dataset, the median cumulative genetic risk (P-Hat) was 0.903 and 0.007 in the case and control groups, respectively, together with 79.9% classification sensitivity and 95.8% specificity. The identified profile shows a significant enrichment of genes involved in the immune response, cell adhesion, cell communication/signaling, nervous system development, and neuronal signaling, including ionotropic glutamate receptors, which have been implicated in the pathological mechanism driving neurodegeneration. In the validation dataset, the median cumulative genetic risk was 0.59 and 0.32 in the case and control groups, respectively, with classification sensitivity 62.3% and specificity 75.9%. No differences in disease progression or T2-lesion volumes were observed among four levels of predicted genetic risk groups (high, medium, low, misclassified). On the other hand, a significant difference (F = 2.75, P = 0.04) was detected for age of disease onset between the affected misclassified as controls (mean = 36 years) and the other three groups (high, 33.5 years; medium, 33.4 years; low, 33.1 years). CONCLUSIONS: The results are consistent with the polygenic model of inheritance. The cumulative genetic risk established using currently available genome-wide association data provides important insights into disease heterogeneity and completeness of current knowledge in MS genetics.