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Introduction Studies document rod fracture in pedicle subtraction osteotomy (PSO) settings where disk spaces were preserved above or adjacent to the PSO. This study compares the multidirectional bending rigidity and fatigue life of PSO segments with or wit

Intraoperative contouring of posterior rods in lumbar arthrodesis constructs introduces stress concentrations that can substantially reduce fatigue life. The sensitivity of titanium (Ti) and stainless steel (SS) to intraoperative contouring has been established in the literature; however, notch sensitivity has yet to be quantified for cobalt chrome (CoCr), which is now being advocated for use in posterior arthrodesis constructs. The goal of this study is to evaluate the sensitivity of CoCr rods to intraoperative contouring for posterior lumbar screwrod arthrodesis constructs. In this paper lumbar bilateral vertebrectomy models are constructed based on ASTM F1717-01 with curved rods (26-30 degrees total curvature) and poly-axial pedicle screws. Three types of constructs are assembled: first, 5.5 mm SS rods with SS screws (6.5 x 35 mm), second, 6.0 mm Ti rods with Ti screws (7.5 x 35 mm), and third, 6.0 mm CoCr rods with Ti screws (7.5 x 35 mm). All specimens are tested at 4 Hz in dynamic axial compression-bending with a load ratio of ten and maximum load levels of 250, 400, and 700 N until run-out at 2 000 000 cycles. Results are presented that show that the fatigue life of CoCr constructs tend to be greater than Ti constructs at all levels. At the 400 N maximum loading, CoCr lasts an average of 350 000 cycles longer than the Ti constructs. The CoCr constructs are able to sustain the 250 N load until run-out at 2 000 000 cycles but they fail at high load levels (maximum 700 N). The CoCr constructs fail at the neck of the Ti screw at high loads whereas Ti screws fail at the notch induced by contouring. Since CoCr is compatible with magnetic resonance imaging and has high static strength characteristics, the results of this study suggest that it may be an appropriate substitute for Ti. [ABSTRACT FROM AUTHOR]

Accurately quantifying the compressive stiffnesses of whole human vertebrae is important in the development of new treatment regimes for fractures due to osteoporosis or metastatic involvement. Two methods are commonly used to quantify compressive stiffnesses of whole vertebrae: first, the maximum slope of the force-deformation curve over a 0.2 per cent strain window; second, the slope of the best-fit line to the load-deflection curve over a specified loading range. Because the whole bone load-displacement response is non-linear, these two measurement systems yield different stiffness values for the same set of experimental data. Thus, the goal of this study was to develop and validate a standard method for deriving the whole bone stiffnesses of human vertebrae. Data from uniaxial compression tests on isolated human thoracic vertebrae (N=30 from 24 donors; T7-T10; age, 84 +/- 10, seven male, and 17 female) were analysed using the two aforementioned stiffness measurement techniques. A sensitivity analysis was also conducted whereby stiffness values were calculated for strain windows ranging from 0.05 per cent to 10 per cent. The results showed that the whole vertebra stiffness was sensitive to the calculation method. Using strain window approaches, the calculated stiffness was erratic at small strain ranges (less than 0.75 per cent), but it began to stabilize at 1 per cent strain. Comparing the historical measurement techniques versus the new standard, it was found that the 1 per cent and 0.2 per cent strain window techniques were well correlated (R2 = 0.91; p < 0.01); however, compared with the 1 per cent strain window method, the 0.2 per cent technique consistently overestimated stiffness and had five times the sensitivity to small changes in strain window magnitude. In conclusion, it is recommended that the 1 per cent strain window technique is adopted as a new standard for measuring the whole bone compressive stiffnesses of human vertebrae based on this method's superior level of accuracy and repeatability when compared with current techniques. The adoption of such a standard in the biomechanics field is important because it allows for inter-study comparisons of new orthopaedic treatments, such as vertebroplasty products. [ABSTRACT FROM AUTHOR]

Purpose: Stationary training rollers enable wheelchair users to maintain physical health and train as athletes, which serves to treat and prevent immobility-associated chronic disease and improve cardiorespiratory fitness required for sports performance. However, conventional exercise equipment is largely inaccessible for persons with disabilities in low-resource areas, primarily due to cost. The aim of this study was to prototype, develop, and test a portable, cost-efficient stationary training device for wheelchair users in low-resource settings - The EasyRoller., Materials and Methods: Stakeholder input from wheelchair athletes, trainers, and potential commercial manufacturers was solicited and utilized to conceptualize The EasyRoller design. The device was constructed from easily sourced, low cost components, following which it was user-tested with Para athletes. Feedback was analysed and incorporated into newer versions of the prototype. Results and conclusions: The EasyRoller creatively combines easily-sourced components to significantly cut down cost and ease both manufacture and repair for use in low-resource settings. The device is portable with a total weight of 34 pounds and total size of 42 linear inches while also affordable with a total cost of USD$199. Hereby, The EasyRoller has the potential to increase physical activity participation in populations with impairment who live in socioeconomically deprived world regions.Implications for rehabilitationExercise and physical activity are key aspects of health and quality of life for persons with disabilitiesStationary training rollers, devices that enable wheelchair users to train, are often bulky and expensive and therefore inaccessible for populations in socio-economically disadvantaged settingsThe EasyRoller is a portable and affordable training device that increases access to exercise and physical activity for these populations.

Tuft cells are rare chemosensory sentinels found in the gut epithelium. When triggered by helminth infection, tuft cells secrete interleukin-25 (IL-25) basolaterally and subsequently evoke an immune response. Irritable bowel syndrome (IBS) is a common and heterogeneous disorder characterized by bowel dysfunction and visceral pain sensitivity. Dysfunctional gut-brain communication and immune activation contribute to the pathophysiology of this disorder. The study aims were to investigate changes in tuft cell density in non-post-infectious IBS patients. Immunofluorescent labeling of DCLK1-positive tuft cells was carried out in mucosal biopsies from the distal colons of diarrhea and constipation-predominant IBS patients and healthy controls. Tuft cell numbers were also assessed in animal models. Concentrations of interleukin-25 (IL-25) secreted from colonic biopsies and in plasma samples were analyzed using an immunoassay. The density of tuft cells was increased in diarrhea-but not constipation-predominant IBS patient colonic biopsies. Biopsy secretions and plasma concentrations of IL-25 were elevated in diarrhea-but not constipation-predominant IBS participants. Tuft cell hyperplasia was detected in a rat model of IBS but not in mice exposed to chronic stress. Tuft cell hyperplasia is an innate immune response to helminth exposure. However, the patients with diarrhea-predominant IBS have not reported any incidents of enteric infection. Moreover, rats exhibiting IBS-like symptoms displayed increased tuft cell density but were not exposed to helminths. Our findings suggest that factors other than helminth exposure or chronic stress lead to tuft cell hyperplasia in IBS colonic biopsies., (Copyright © 2020 Aigbologa, Connolly, Buckley and O'Malley.)

An intact gut epithelium preserves the immunological exclusion of "non-self" entities in the external environment of the gut lumen. Nonetheless, information flows continuously across this interface, with the host immune, endocrine, and neural systems all involved in monitoring the luminal environment of the gut. Both pathogenic and commensal gastrointestinal (GI) bacteria can modulate centrally-regulated behaviors and brain neurochemistry and, although the vagus nerve has been implicated in the microbiota-gut-brain signaling axis, the cellular and molecular machinery that facilitates this communication is unclear. Studies were carried out in healthy Sprague-Dawley rats to understand cross-barrier communication in the absence of disease. A novel colonic-nerve electrophysiological technique was used to examine gut-to-brain vagal signaling by bacterial products. Calcium imaging and immunofluorescent labeling were used to explore the activation of colonic submucosal neurons by bacterial products. The findings demonstrate that the neuromodulatory molecule, glucagon-like peptide-1 (GLP-1), secreted by colonic enteroendocrine L-cells in response to the bacterial metabolite, indole, stimulated colonic vagal afferent activity. At a local level indole modified the sensitivity of submucosal neurons to GLP-1. These findings elucidate a cellular mechanism by which sensory L-cells act as cross-barrier signal transducers between microbial products in the gut lumen and the host peripheral nervous system., (Copyright © 2020 Buckley, O’Brien, Brosnan, Ross, Stanton, Buckley and O’Malley.)

Background: Patients with irritable bowel syndrome (IBS) may experience postprandial symptom exacerbation. Nutrients stimulate intestinal release of glucagon-like peptide 1 (GLP-1), an incretin hormone with known gastrointestinal effects. However, prior to the postprandial rise in GLP-1, levels of the hunger hormone, ghrelin, peak. The aims of this study were to determine if ghrelin sensitizes colonic intrinsic and extrinsic neurons to the stimulatory actions of a GLP-1 receptor agonist, and if this differs in a rat model of IBS., Methods: Calcium imaging of enteric neurons was compared between Sprague Dawley and Wistar Kyoto rats. Colonic contractile activity and vagal nerve recordings were also compared between strains., Key Results: Circulating GLP-1 concentrations differ between IBS subtypes. Mechanistically, we have provided evidence that calcium responses evoked by exendin-4, a GLP-1 receptor agonist, are potentiated by a ghrelin receptor (GHSR-1) agonist, in both submucosal and myenteric neurons. Although basal patterns of colonic contractility varied between Sprague Dawley and Wister Kyoto rats, the capacity of exendin-4 to alter smooth muscle function was modified by a GHSR-1 agonist in both strains. Gut-brain signaling via GLP-1-mediated activation of vagal afferents was also potentiated by the GHSR-1 agonist., Conclusions & Inferences: These findings support a temporal interaction between ghrelin and GLP-1, where the preprandial peak in ghrelin may temporarily sensitize colonic intrinsic and extrinsic neurons to the neurostimulatory actions of GLP-1. While the sensitizing effects of the GHSR-1 agonist were identified in both rat strains, in the rat model of IBS, underlying contractile activity was aberrant., (© 2019 John Wiley & Sons Ltd.)

An overwhelming majority of hospitalized patients undergo intravenous (IV) catheter insertion in order to receive hydration and necessary medication. Current IV insertion training techniques include manikins that are unable to react or give feedback to the trainee. The Avstick® is a realistic training device that can be worn by an actor, allowing a nurse trainee to perform an IV catheter insertion on a live patient without causing the person harm. The purpose of this study is to demonstrate the effectiveness of the Avstick in nursing education to increase nurse-patient communication and trainee self-efficacy.

Purpose: The aim of this study was to investigate the influence of age at diagnosis of atypical hyperplasia ("atypia", ductal [ADH], lobular [ALH], or severe ADH) on the risk of developing subsequent invasive breast cancer or ductal carcinoma in situ (DCIS)., Methods: Using standard survival analysis methods, we retrospectively analyzed 1353 women not treated with chemoprevention among a cohort of 2370 women diagnosed with atypical hyperplasia to determine the risk relationship between age at diagnosis and subsequent breast cancer., Results: For all atypia diagnoses combined, our cohort showed a 5-, 10-, and 15-year risk of invasive breast cancer or DCIS of 0.56, 1.25, and 1.30, respectively, with no significant difference in the (65,75] year age group. For women aged (35,75] years, we observed no significant difference in the 15-year risk of invasive breast cancer or DCIS after atypical hyperplasia, although the baseline risk for a 40-year-old woman is approximately 1/8 the risk of a 70-year-old woman. The risks associated with invasive breast cancer or DCIS for women in our cohort diagnosed with ADH, severe ADH, or ALH, regardless of age, were 7.6% (95% CI 5.9-9.3%) at 5 years, 25.1% (20.7-29.2%) at 10 years, and 40.1% (32.8-46.6%) at 15 years., Conclusion: In contrast to current risk prediction models (e.g., Gail, Tyrer-Cuzick) which assume that the risk of developing breast cancer increases in relation to age at diagnosis of atypia, we found the 15-year cancer risk in our cohort was not significantly different for women between the ages of 35 (excluded) and 75. This implies that the "hits" received by the breast tissue along the "high-risk pathway" to cancer might possibly supersede other factors such as age.

Purpose: Extracting information from electronic medical record is a time-consuming and expensive process when done manually. Rule-based and machine learning techniques are two approaches to solving this problem. In this study, we trained a machine learning model on pathology reports to extract pertinent tumor characteristics, which enabled us to create a large database of attribute searchable pathology reports. This database can be used to identify cohorts of patients with characteristics of interest., Methods: We collected a total of 91,505 breast pathology reports from three Partners hospitals: Massachusetts General Hospital, Brigham and Women's Hospital, and Newton-Wellesley Hospital, covering the period from 1978 to 2016. We trained our system with annotations from two datasets, consisting of 6295 and 10,841 manually annotated reports. The system extracts 20 separate categories of information, including atypia types and various tumor characteristics such as receptors. We also report a learning curve analysis to show how much annotation our model needs to perform reasonably., Results: The model accuracy was tested on 500 reports that did not overlap with the training set. The model achieved accuracy of 90% for correctly parsing all carcinoma and atypia categories for a given patient. The average accuracy for individual categories was 97%. Using this classifier, we created a database of 91,505 parsed pathology reports., Conclusions: Our learning curve analysis shows that the model can achieve reasonable results even when trained on a few annotations. We developed a user-friendly interface to the database that allows physicians to easily identify patients with target characteristics and export the matching cohort. This model has the potential to reduce the effort required for analyzing large amounts of data from medical records, and to minimize the cost and time required to glean scientific insight from these data.

Study Design: In vitro cadaver biomechanics study., Objective: The goal of this study is to compare the in situ fatigue life of expandable versus fixed interbody cage designs., Summary of Background Data: Expandable cages are becoming more popular, in large part, due to their versatility; however, subsidence and catastrophic failure remain a concern. This in vitro analysis investigates the fatigue life of expandable and fixed interbody cages in a single level human cadaver corpectomy model by evaluating modes of subsidence of expandable and fixed cages as well as change in stiffness of the constructs with cyclic loading., Methods: Nineteen specimens from 10 human thoracolumbar spines (T10-L2, L3-L5) were biomechanically evaluated after a single level corpectomy that was reconstructed with an expandable or fixed cage and anterior dual rod instrumentation. All specimens underwent 98 K cycles to simulate 3 months of postoperative weight bearing. In addition, a third group with hyperlordotic cages was used to simulate catastrophic failure that is observed in clinical practice., Results: Three fixed and 2 expandable cages withstood the cyclic loading despite perfect sagittal and coronal plane fitting of the endcaps. The majority of the constructs settled in after initial subsidence. The catastrophic failures that were observed in clinical practice could not be reproduced with hyperlordotic cages. However, all cages in this group subsided, and 60% resulted in endplate fractures during deployment of the cage., Conclusions: Despite greater surface contact area, expandable cages have a trend for higher subsidence rates when compared with fixed cages. When there is edge loading as in the hyperlordotic cage scenario, there is a higher risk of subsidence and intraoperative fracture during deployment of expandable cages.

Background: Young age at breast cancer diagnosis has been associated with increased risk of recurrence and mortality. We reevaluated this assumption in a large, modern cohort of women diagnosed with breast cancer at age ≤40 years., Methods: We identified women with breast cancer at age ≤40 years at a single institution from 1996-2008. We assessed locoregional recurrence (LRR), distant recurrence, disease-free survival (DFS), and overall survival (OS), and correlated patient and tumor characteristics with outcomes., Results: We identified 584 women aged ≤40 years with breast cancer. Median age was 37 years, and median follow-up was 124 months; 61.5 % were stages 0-I and 38.5 % were stages II-III. Overall, 57.4 % had lumpectomies and 42.5 % mastectomies. DFS was 93 % at 5 years and 84.5 % at 10 years. OS was 93 % at 5 years and 86.5 % at 10 years. On multivariate analysis, worse DFS was associated with positive nodes (p = 0.002); worse OS was associated with larger tumor size (p = 0.042). When stratified by lumpectomy versus mastectomy, there were no significant differences in survival or recurrence. For lumpectomy patients, DFS was 96 % at 5 years and 88 % at 10 years; OS was 96 % at 5 years and 89 % at 10 years. For mastectomy patients, DFS was 89.5 % at 5 years and 79 % at 10 years; OS was 90 % at 5 years and 83 % at 10 years. Lumpectomy LRR rates were 1 % at 5 years and 4 % at 10 years. Mastectomy LRR rates were 3.5 % at 5 years and 8.7 % at 10 years., Conclusions: Outcomes for women with breast cancer at age ≤40 years have improved. Lumpectomy recurrence rates are low, suggesting that lumpectomy is oncologically safe for young breast cancer patients.

Background: Orthopaedic surgery lags behind other surgical specialties in terms of gender diversity. The percentage of women entering orthopaedic residency persistently remains at 14% despite near equal ratios of women to men in medical school classes. This trend has been attributed to negative perceptions among women medical students of workplace culture and lifestyle in orthopaedics as well as lack of exposure, particularly during medical school when most women decide to enter the field. Since 2012, The Perry Initiative, a nonprofit organization that is focused on recruiting and retaining women in orthopaedics, had conducted extracurricular outreach programs for first- and second-year female medical students to provide exposure and mentoring opportunities specific to orthopaedics. This program, called the Medical Student Outreach Program (MSOP), is ongoing at medical centers nationwide and has reached over 300 medical students in its first 3 program years (2012-2014)., Questions/purposes: (1) What percentage of MSOP participants eventually match into orthopaedic surgery residency? (2) Does MSOP impact participants' perceptions of the orthopaedics profession as well as intellectual interest in the field?, Methods: The percentage of program alumnae who matched into orthopaedics was determined by annual followup for our first two cohorts who graduated from medical school. All program participants completed a survey immediately before and after the program that assessed the impact of MSOP on the student's intention to pursue orthopaedics as well as perceptions of the field and intellectual interest in the discipline., Results: The orthopaedic surgery match rate for program participants was 31% in our first graduating class (five of 16 participants in 2015) and 28% in our second class (20 of 72 participants in 2016). Pre/post program comparisons showed that the MSOP influenced students' perceptions of the orthopaedics profession as well as overall intellectual interest in the field., Conclusions: The results of our study suggest that The Perry Initiative's MSOP positively influences women to choose orthopaedic surgery as a profession. The match rate for program alumnae is twice the percentage of females in current orthopaedic residency classes. Given these positive results, MSOP can serve as a model, both in its curricular content and logistic framework, for other diversity initiatives in the field.

Background: There is little in-depth research into how patients feel about emergency medical trials, and what influences these feelings., Objectives: To investigate patients' feelings on taking part in emergency medical research, particularly trials conducted without prospective consent., Methods: Seventeen inpatients, all recently admitted with a medical emergency, were interviewed. Questions focused on feelings on taking part in hypothetical trials, particularly trials conducted with deferred consent., Results: Five main themes were identified. Level of trust in the medical profession-high levels of trust tended to correlate with willingness to participate in trials. Previous bad healthcare experiences tended to diminish trust. Concerns for personal well-being-patients identified a conflict between aversion to unknown side effects and desire for access to newer and potentially better treatments. Some would be less inclined to participate in research if they were severely unwell, some more so. Altruism-many cited the importance of helping to advance medical knowledge and of 'giving back to the health service'. Concerns over autonomy-some felt that deferred consent was a violation of personal autonomy. Uncertainty-many patients seemed to struggle to understand the more complex concepts discussed., Conclusions: Patients are broadly trusting, and open to participating in emergency medical trials, but want to be kept as informed as possible throughout the process. Willingness may be improved by providing more complete explanations, although this may be limited by the complexity of relevant concepts. Good communication and improved public understanding of clinical trials would likely increase acceptance of emergency care research., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Background: A person's ability to move his or her arms against gravity is important for independent performance of critical activities of daily living and for exploration that facilitates early cognitive, language, social, and perceptual-motor development. Children with a variety of diagnoses have difficulty moving their arms against gravity., Objective: The purpose of this technical report is to detail the design process and initial testing of a novel exoskeletal garment, the Playskin Lift, that assists and encourages children to lift their arms against gravity., Design: This report details the design theory and process, the device, and the results of field testing with a toddler with impaired upper extremity function due to arthrogryposis multiplex congenita., Results: The Playskin Lift is an inexpensive (<$30 material costs), easy to use (5/5 rating), comfortable (5/5 rating), and attractive (4/5 rating) device. While wearing the device, the child was able to contact objects more often throughout an increased play space, to look at toys more while contacting them, and to perform more complex interactions with toys., Limitations: This report details initial testing with one child. Future testing with more participants is recommended., Conclusions: These results suggest that by considering the broad needs of users, including cost, accessibility, comfort, aesthetics, and function, we can design inexpensive devices that families and clinicians can potentially fabricate in their own communities to improve function, participation, exploration, and learning for children with disabilities., (© 2016 American Physical Therapy Association.)

Objectives: Micro-CT is a promising modality to determine breast tumour size in three dimensions in intact lumpectomy specimens. We compared the accuracy of tumour size measurements using specimen micro-CT with measurements using multimodality pre-operative imaging., Methods: A tabletop micro-CT was used to image breast lumpectomy specimens. The largest tumour dimension on three-dimensional reconstructed micro-CT images of the specimen was compared with the measurements determined by pre-operative mammography, ultrasound and MRI. The largest dimension of pathologic invasive cancer size was used as the gold standard reference to assess the accuracy of imaging assessments., Results: 50 invasive breast cancer specimens in 50 patients had micro-CT imaging. 42 were invasive ductal carcinoma, 6 were invasive lobular carcinoma and 2 were other invasive cancer. Median patient age was 63 years (range 33-82 years). When compared with the largest pathologic tumour dimension, micro-CT measurements had the best correlation coefficient (r = 0.82, p < 0.001) followed by MRI (r = 0.78, p < 0.001), ultrasound (r = 0.61, p < 0.001) and mammography (r = 0.40, p < 0.01). When compared with pre-operative modalities, micro-CT had the best correlation coefficient (r = 0.86, p < 0.001) with MRI, followed by ultrasound (r = 0.60, p < 0.001) and mammography (r = 0.54, p < 0.001). Overall, mammography and ultrasound tended to underestimate the largest tumour dimension, while MRI and micro-CT overestimated the largest tumour dimension more frequently., Conclusion: Micro-CT is a potentially useful tool for accurate assessment of tumour dimensions within a lumpectomy specimen. Future studies need to be carried out to see if this technology could have a role in margin assessment., Advances in Knowledge: Micro-CT is a promising new technique which could potentially be used for rapid assessment of breast cancer dimensions in an intact lumpectomy specimen in order to guide surgical excision.

Object: Reconstruction after total sacrectomy is a critical component of malignant sacral tumor resection, permitting early mobilization and maintenance of spinal pelvic alignment. However, implant loosening, graft migration, and instrumentation breakage remain major problems. Traditional techniques have used interiliac femoral allograft, but more modern methods have used fibular or cage struts from the ilium to the L-5 endplate or sacral body replacement with transiliac bars anchored to cages to the L-5 endplate. This study compares the biomechanical stability under gait-simulating fatigue loading of the 3 current methods., Methods: Total sacrectomy was performed and reconstruction was completed using 3 different constructs in conjunction with posterior spinal screw rod instrumentation from L-3 to pelvis: interiliac femur strut allograft (FSA); L5-iliac cage struts (CSs); and S-1 body replacement expandable cage (EC). Intact lumbar specimens (L3-sacrum) were tested for flexion-extension range of motion (FE-ROM), axial rotation ROM (AX-ROM), and lateral bending ROM (LB-ROM). Each instrumented specimen was compared with its matched intact specimen to generate an ROM ratio. Fatigue testing in compression and flexion was performed using a custom-designed long fusion gait model., Results: Compared with intact specimen, the FSA FE-ROM ratio was 1.22 ± 0.60, the CS FE-ROM ratio was significantly lower (0.37 ± 0.12, p < 0.001), and EC was lower still (0.29 ± 0.14, p < 0.001; values are expressed as the mean ± SD). The difference between CS and EC in FE-ROM ratio was not significant (p = 0.83). There were no differences in AX-ROM or LB-ROM ratios (p = 0.77 and 0.44, respectively). No failures were noted on fatigue testing of any EC construct (250,000 cycles). This was significantly improved compared with FSA (856 cycles, p < 0.001) and CS (794 cycles, p < 0.001)., Conclusions: The CS and EC appear to be significantly more stable constructs compared with FSA with FE-ROM. The 3 constructs appear to be equal with AX-ROM and LB-ROM. Most importantly, EC appears to be significantly more resistant to fatigue compared with FSA and CS. Reconstruction of the load transfer mechanism to the pelvis via the L-5 endplate appears to be important in maintenance of alignment after total sacrectomy reconstruction.

The goal of this study was to evaluate the biomechanical properties of an alternative method for connecting sutures using a crimp and to compare this method with a knot connection. Multifilament stainless steel suture (3-0 USP size) was connected by means of knot tying or crimp application and compared with FiberWire (3-0 USP size) connected by knot tying. Ultimate tensile strength (UTS) and stiffness were tested on a servohydraulic testing machine. The total UTS of the crimped constructs was significantly stronger and stiffer than the knotted groups, although the strength per strand was not statistically significant. Crimps offer an alternative method for connecting sutures. They have mechanical advantages over knot tying and allow the connection of multiple suture strands as well as the additional advantage of attaching both sides of the repair independently. This may provide precise pretensioning and potentially reduced surgical exposure.

Treatment of posterior wall (PW) fractures of the acetabulum is guided by the size of the broken wall fragment and by hip instability. Biomechanical testing of hip instability typically is done by simulating the single-leg-stance (SLS) phase of gait, but this does not represent daily activities, such as sit-to-stand (STS) motion. We conducted a study to examine and compare hip instability after PW fractures in SLS and STS loading. We hypothesized that wall fragment size and distance from the dome (DFD) of the acetabulum to the simulated fracture would correlate with hip instability and, in the presence of a PW fracture, the hip would be more unstable during STS loading than during SLS loading. Incremental PW osteotomies were made in 6 cadaveric acetabula. After each osteotomy, a 1200-N load was applied to the acetabulum to simulate SLS and STS loading until dislocation occurred. All hip joints in the cadaveric models were more unstable in STS loading than in SLS loading. PW fragments at time of dislocation were larger (P<.001) in SLS loading (85% ± 13%; range, 81%-100%) than in STS loading (40% ± 7%; range, 33%-52%). Mean (SD) DFD at time of dislocation was 15.0 (3.5) mm (range, 14.4-19.6 mm) in STS loading and 5.3 (4.3) mm (range, 0.1-10.0 mm) in SLS loading (P<.04). There was more hip instability in STS loading than in SLS loading. In STS loading, hips dislocated with a PW fracture size of 33% or more and a DFD of 20 mm or less.

Microscopically clear lumpectomy margins are essential in breast conservation, as involved margins increase local recurrence. Currently, 18-50% of lumpectomies have close or positive margins that require re-excision. We assessed the ability of micro-computed tomography (micro-CT) to evaluate lumpectomy shaved cavity margins (SCM) intraoperatively to determine if this technology could rapidly identify margin involvement by tumor and reduce re-excision rates. Twenty-five SCM from six lumpectomies were evaluated with a Skyscan 1173 table top micro-CT scanner (Skyscan, Belgium). Micro-CT results were compared to histopathological results. We scanned three SCM at once with a 7-minute scanning protocol, and studied a total of 25 SCM from six lumpectomies. Images of the SCM were evaluated for radiographic signs of breast cancer including clustered microcalcifications and spiculated masses. SCM were negative by micro-CT in 19/25 (76%) and negative (≥2 mm) by histopathology in 19/25 (76%). Margin status by micro-CT was concordant with histopathology in 23/25 (92%). Micro-CT overestimated margin involvement in 1/25 and underestimated margin involvement in 1/25. Micro-CT had an 83.3% positive predictive value, a 94.7% negative predictive value, 83.3% sensitivity, and 94.7% specificity for evaluation of SCM. Evaluation of SCM by micro-CT is an accurate and promising method of intraoperative margin assessment in breast cancer patients. The scanning time required is short enough to permit real-time feedback to the operating surgeon, allowing immediate directed re-excision., (© 2013 Wiley Periodicals, Inc.)

Intraoperative radiographic examination of breast specimens is commonly performed to confirm excision of image-detected breast lesions, but it is not reliable for assessing margin status. A more accurate method of intraoperative breast specimen imaging is needed. Micro-CT provides quantitative imaging parameters, image rotation, and virtual "slicing" of intact breast specimens. We explored the use of micro-CT for assessment of a variety of clinical breast specimens. Specimens were evaluated with a table top micro-CT scanner, Skyscan 1173 (Skyscan, Belgium), with a 40-130 kV, 8 W X-ray source. Skyscan software for 3D image analysis (Dataviewer and CTVox) was employed to review 3D graphics of specimens. Scanning for 7 min and another 7 min for image reconstruction provided the desired resolution for breast specimens. Breast lumpectomy specimens, shaved cavity margins, mastectomy specimens, and axillary lymph nodes were imaged by micro-CT. The micro-CT images could be rotated in all directions and cross sections of internal portions of specimens could be visualized from any angle. This provided information about spatial orientation of masses and calcifications relative to margins in intact lumpectomy specimens. Micro-CT is a potentially useful tool for assessment of breast cancer specimens, allowing real-time analysis of tumor location in breast lumpectomy specimens or shaved cavity margins. Micro-CT may also be useful for assessing sentinel lymph nodes and mastectomy specimens.

Our goal was to investigate and compare the mechanical properties of multifilament stainless steel suture (MFSS) and polyethylene multi-filament core FiberWire in flexor tendon repairs. Flexor digitorum profundus tendons were repaired in human cadaver hands with either a 4-strand cruciate cross-lock repair or 6-strand modified Savage repair using 4-0 and 3-0 multifilament stainless steel or FiberWire. The multifilament stainless steel repairs were as strong as those performed with FiberWire in terms of ultimate load and load at 2 mm gap. This study suggests that MFSS provides as strong a repair as FiberWire. The mode of failure of the MFSS occurred by the suture pulling through the tendon, which suggests an advantage in terms of suture strength.

Background: Rod failure has been reported clinically in pedicle subtraction osteotomy (PSO) to correct flat back deformity., Objective: To characterize the fatigue life of posterior screw-rod constructs in the setting of PSO as a function of the severity of rod contour angle., Methods: A modified ASTM F1717 to 04 was used. Rods were contoured to the appropriate angle for the equivalent 20-, 40-, or 60-degree PSO angles. Testing was performed on a mechanical test frame at 400/40 N and 250/25 N, and specimens were cycled at 4 Hz to failure or run-out at 2,000,000 cycles. The effect of the screw-rod system on fatigue strength of curved rods was compared using Cox proportional hazards regression., Results: At 400 N/40 N, Cox proportional hazards regression indicated that contouring rods from a 20-degree PSO angle to either 40 or 60 degrees significantly decreased fatigue life (hazard ratio = 7863.6, P = .0144). However, contouring rods from a 40-degree PSO angle to 60 degrees had no significant effect on the fatigue life (P > .05). At 250 N/25 N, Cox proportional hazards regression indicated that contouring rods from a 20-degree PSO angle to either 40 or 60 degrees significantly decreased fatigue life (hazard ratio = 7863.6, P = .0144). Furthermore, contouring rods from a 40-degree PSO angle to 60 degrees had a significant effect on the fatigue life (hazard ratio = 7863.6, P = .0144)., Conclusion: Results suggest that in the setting of PSO, the fatigue life of posterior spinal fixation rods depends largely on the severity of the rod angle used to maintain the vertebral angle created by the PSO and is significantly lowered by rod contouring.

Open reduction and internal fixation of a distal radius fracture can leave a volar plate in close proximity or touching the tendons of the wrist. This cadaveric study examines the how volar plate position changes contact pressure and force against the flexor pollicis longus (FPL) tendon in multiple wrist extension positions. This study suggests that moving the plate from an ideal position (distal edge at the watershed line) to a malposition (5 mm distal to the watershed line) significantly increased the force by 72.7% and contact pressure by 33.5% on the FPL. Multiple clinical case reports have described rupture of the flexor tendons associated with distally positioned plates or protruding screw heads, creating prominent or sharp edges. This study illustrates that in order to minimize contact pressure on the flexor tendons, plating distal to the watershed line should be avoided when possible.

Women with atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), lobular carcinoma in situ (LCIS), and severe ADH are at increased risk of breast cancer, but a systematic quantification of this risk and the efficacy of chemoprevention in the clinical setting is still lacking. The objective of this study is to evaluate a woman's risk of breast cancer based on atypia type and to determine the effect of chemoprevention in decreasing this risk. Review of 76,333 breast pathology reports from three institutions within Partners Healthcare System, Boston, from 1987 to 2010 using natural language processing was carried out. This approach identified 2,938 women diagnosed with atypical breast lesions. The main outcome of this study is breast cancer occurrence. Of the 2,938 patients with atypical breast lesions, 1,658 were documented to have received no chemoprevention, and 184/1,658 (11.1 %) developed breast cancer at a mean follow-up of 68 months. Estimated 10-year cancer risks were 17.3 % with ADH, 20.7 % with ALH, 23.7 % with LCIS, and 26.0 % with severe ADH. In a subset of patients treated from 1999 on (the chemoprevention era), those who received no chemoprevention had an estimated 10-year breast cancer risk of 21.3 %, whereas those treated with chemoprevention had a 10-year risk of 7.5 % (p < 0.001). Chemoprevention use significantly reduced breast cancer risk for all atypia types (p < 0.05). The risk of breast cancer with atypical breast lesions is substantial. Physicians should counsel patients with ADH, ALH, LCIS, and severe ADH about the benefit of chemoprevention in decreasing their breast cancer risk.

Introduction Studies document rod fracture in pedicle subtraction osteotomy (PSO) settings where disk spaces were preserved above or adjacent to the PSO. This study compares the multidirectional bending rigidity and fatigue life of PSO segments with or without interbody support. Methods Twelve specimens received bilateral T12-S1 posterior fixation and L3 PSO. Six received extreme lateral interbody fusion (XLIF) cages in addition to PSO at L2-L3 and L3-L4; six had PSO only. Flexion-extension, lateral bending, and axial rotation (AR) tests were conducted up to 7.5 Newton-meters (Nm) for groups: (1) posterior fixation, (2) L3 PSO, (3) addition of cages (six specimens). Relative motion across the osteotomy (L2-L4) and entire fixation site (T12-S1) was measured. All specimens were then fatigue tested for 35K cycles. Results Regardingmultiaxial bending, there was a significant 25.7% reduction in AR range of motion across L2-L4 following addition of cages. Regarding fatigue bending, dynamic stiffness, though not significant (p = 0.095), was 22.2% greater in the PSO + XLIF group than in the PSO-only group. Conclusions Results suggest that placement of interbody cages in PSO settings has a potential stabilizing effect, which is modestly evident in the acute setting. Inserting cages in a second-stage surgery remains a viable option and may benefit patients in terms of recovery but additional clinical studies are necessary to confirm this.

Object: Expandable cages are becoming more popular due in large part to their versatility, but subsidence and catastrophic failure remain a concern. One of the proposed reasons of failure is edge loading of the endplate caused by a mismatch between the sagittal alignment of the motion segment and cage. This in vitro analysis investigates the endplate forces characteristic of expandable and fixed interbody cages in a single-level human cadaver corpectomy model., Methods: Ten human thoracolumbar spines (T10-L2, L3-5) were biomechanically evaluated following a single-level corpectomy that was reconstructed with an expandable or fixed cage. Fixed cages were deployed with the best-fitting end cap combination, whereas expandable cages were deployed in normal, hypolordotic, and hyperlordotic alignment scenarios. The endplate forces and contact area were measured with a pressure measurement system, and the expansion torque applied by the surgeon was measured with a custom-made insertion device., Results: The contact areas of the expandable cages were, in general, higher than those of the fixed cages. The endplate forces of the expandable cages were similar to those of the fixed cages in the normal alignment scenario. Higher endplate forces were observed in the hyperlordotic scenario, whereas the endplate forces in the hypolordotic and normal alignment scenarios were similar. There was no correlation with the expansion torque and the final endplate forces., Conclusions: Expandable cages resulted in consistently higher contact area and endplate forces when compared with the fixed cages. Because the expansion torque does not correlate with the final endplate forces, surgeons should not rely solely on tactile feedback during deployment of these cages.

Introduction: Current recommendations relating to the treatment of acetabular fractures are based on studies that evaluate the loading patterns associated with normal gait despite the fact that the forces on the acetabulum are significantly greater during sit-to-stand activities. We hypothesize that this increased force will lead to greater instability when an acetabular fracture occurs, and our goal was to compare cadaveric hip stability during single-leg-stance (SLS) and sit-to-stand (STS) maneuvers using a transverse acetabular fracture model., Methods: Seven fresh-frozen cadaveric hemipelvic specimens with proximal femurs were dissected of all soft tissues. Transverse acetabular osteotomies were created in 5-mm increments from distal to proximal. The roof arc angle and decrease of articular surface area were measured after each osteotomy, and the specimens were tested in SLS and STS. A 1200-N load was applied and visible dislocation was recorded for each loading orientation., Results: The average roof arc angle needed to dislocate in the SLS position was 46.1° in the anteroposterior, 71.9° in the iliac oblique, and 25.2° in the obturator oblique views compared with 90.9° in anteroposterior, 101.4° in iliac oblique, and 67.3° in obturator oblique views for the STS orientation (P < 0.003 for all radiographic views). The decrease in articular surface area needed to dislocate the hip was significantly less for the STS group (10.9%) than the SLS group (36.4%) (P = 0.003)., Conclusions: There is significantly greater hip instability seen with STS loading of a transverse acetabular model than with simple SLS loading. This would suggest that some fractures previously deemed stable may show significant instability during common activities of daily living, and reassessment of nonoperative treatment may be indicated.

We conducted a study to evaluate the congruency of fit of current scapular plate designs. Three-dimensional image-processing and -analysis software, and computed tomography scans of 12 cadaveric scapulae were used to generate 3 measurements: mean distance from plate to bone, maximum distance, and percentage of plate surface within 2 mm of bone. These measurements were used to quantify congruency. The scapular spine plate had the most congruent fit in all 3 measured variables. The lateral border and glenoid plates performed statistically as well as the scapular spine plate in at least 1 of the measured variables. The medial border plate had the least optimal measurements in all 3 variables. With locking-plate technology used in a wide variety of anatomical locations, the locking scapula plate system can allow for a fixed-angle construct in this region. Our study results showed that the scapular spine, glenoid, and lateral border plates are adequate in terms of congruency. However, design improvements may be necessary for the medial border plate. In addition, we describe a novel method for quantifying hardware congruency, a method that can be applied to any anatomical location.

Pure moment testing has become a standard protocol for in vitro assessment of the effect of surgical techniques or devices on the bending rigidity of the spine. Of the methods used for pure moment testing, cable-driven set-ups are popular due to their low requirements and simple design. Fixed loading rings are traditionally used in conjunction with these cable-driven systems. However, the accuracy and validity of the loading conditions applied with fixed ring designs have raised some concern, and discrepancies have been found between intended and prescribed loading conditions for flexion-extension. This study extends this prior work to include lateral bending and axial torsion, and compares this fixed ring design with a novel "3D floating ring" design. A complete battery of multi-axial bending tests was conducted with both rings in multiple different configurations using an artificial lumbar spine. Applied moments were monitored and recorded by a multi-axial load cell at the base of the specimen. Results indicate that the fixed ring design deviates as much as 77% from intended moments and induces non-trivial shear forces (up to 18 N) when loaded to a non-destructive maximum of 4.5 Nm. The novel 3D floating ring design largely corrects the inherent errors in the fixed ring design by allowing additional directions of unconstrained motion and producing uniform loading conditions along the length of the specimen. In light of the results, it is suggested that the 3D floating ring set-up be used for future pure moment spine biomechanics applications using a cable-driven apparatus., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Filling the empty holes in peri-articular locking plates may improve the fatigue strength of the fixation. The purpose of this in vitro study was to investigate the effect of plugging the unused holes on the fatigue life of peri-articular distal femoral plates used to fix a comminuted supracondylar fracture model. A locking/compression plate was applied to 33 synthetic femurs and then a 6 cm metaphyseal defect was created (AO Type 33-A3). The specimens were then divided into three groups: unplugged, plugged with locking screw only and fully plugged holes. They were then tested using a stepwise or run-out fatigue protocol, each applying cyclic physiological multiaxial loads. All specimens in the stepwise group failed at the 770 N load level. The mean number of cycles to failure for the stepwise specimen was 25,500 cycles (SD 1500), 28,800 cycles (SD 6300), and 26,400 cycles (SD 2300) cycles for the unplugged, screw only and fully plugged configurations, respectively (p = 0.16). The mean number of cycles to failure for the run-out specimens was 42,800 cycles (SD 10,700), 36,000 cycles (SD 7200), and 36,600 cycles (SD 10,000) for the unplugged, screw only and fully plugged configurations, respectively (p = 0.50). There were also no differences in axial or torsional stiffness between the constructs. The failures were through the screw holes at the level of comminution. In conclusion, filling the empty combination locking/compression holes in peri-articular distal femur locking plates at the level of supracondylar comminution does not increase the fatigue life of the fixation in a comminuted supracondylar femoral fracture model (AO 33-A3) with a 6 cm gap.

Objective: The opportunity to integrate clinical decision support systems into clinical practice is limited due to the lack of structured, machine readable data in the current format of the electronic health record. Natural language processing has been designed to convert free text into machine readable data. The aim of the current study was to ascertain the feasibility of using natural language processing to extract clinical information from >76,000 breast pathology reports. APPROACH AND PROCEDURE: Breast pathology reports from three institutions were analyzed using natural language processing software (Clearforest, Waltham, MA) to extract information on a variety of pathologic diagnoses of interest. Data tables were created from the extracted information according to date of surgery, side of surgery, and medical record number. The variety of ways in which each diagnosis could be represented was recorded, as a means of demonstrating the complexity of machine interpretation of free text., Results: There was widespread variation in how pathologists reported common pathologic diagnoses. We report, for example, 124 ways of saying invasive ductal carcinoma and 95 ways of saying invasive lobular carcinoma. There were >4000 ways of saying invasive ductal carcinoma was not present. Natural language processor sensitivity and specificity were 99.1% and 96.5% when compared to expert human coders., Conclusion: We have demonstrated how a large body of free text medical information such as seen in breast pathology reports, can be converted to a machine readable format using natural language processing, and described the inherent complexities of the task.

The use of antibiotic-impregnated polymethylmethacrylate in joint arthroplasty is widespread. The Food and Drug Administration has approved commercially prepared antibiotic bone cement, but in a climate of increasingly drug-resistant bacteria, orthopedic surgeons often hand-mix their own. A recent study reported the effects on drug elution of different mixing methods designed to decrease antibiotic particle size and distribute those particles more uniformly. Theoretically, these mixing techniques could also improve antibiotic cement strength; however, the actual effects of these techniques on cement strength are undefined. In the present study, 3 different methods of mixing vancomycin with bone cement were compared. We conclude that the addition of vancomycin to polymethylmethacrylate at commonly accepted concentrations does substantially decrease cement strength and that more complex mixing techniques do not improve cement strength significantly., (Copyright © 2011 Elsevier Inc. All rights reserved.)

ST2, a member of the Toll/IL-1R superfamily, negatively regulates both TLR2 and TLR4 signaling. In this study, we report that ST2-deficient mice were more susceptible to polymicrobial sepsis than their wild-type littermates, with increased production of proinflammatory cytokines. Bacterial clearance from the circulation and visceral organs following polymicrobial infection was markedly impaired in ST2-deficient mice. This was associated with substantially reduced uptake, phagocytosis, and intracellular killing of both Gram-positive and Gram-negative bacteria by ST2-deficient phagocytes. Consistent with a reduced antimicrobial response, phagocytes lacking ST2 displayed a defect in bactericidal activity in response to bacterial challenges with severely impaired phagosome maturation and NOX2 function. Thus, ST2-deficient mice exhibit an increased susceptibility to polymicrobial infection with impaired bacterial clearance, which is associated with defects in phagosome maturation and NOX2-derived production of reactive oxygen species characterized in ST2-deficient phagocytes.

Background: The benefits of taking shaved cavity margins (SCM) at the time of lumpectomy are unclear. We sought to determine if taking SCM decreases re-excision rates by increasing the total breast tissue volume excised., Methods: We undertook a retrospective review of breast cancer patients who underwent lumpectomy from 2004 to 2006. Patients were divided into three groups. Group 1 had lumpectomy alone, group 2 had lumpectomy plus select (1-3) SCM, and group 3 had lumpectomy plus complete (≥4) SCM. Pathologic findings and surgical outcomes were compared between groups., Results: 773 cancers treated by lumpectomy were included in this study; 197 were in group 1, 130 were in group 2, and 446 were in group 3. The mean total volume of breast tissue excised in group 1 (106.6 cm(3)) was significantly larger than the volume excised in groups 2 (79.3 cm(3)) and 3 (76.3 cm(3)). Rates of re-excision and successful breast-conservation therapy (BCT) were not significantly different between groups. Despite a lower total volume of breast tissue excised in groups 2 and 3, there was no significant increase in locoregional recurrence rates (LRR) at median follow-up of 54 months., Conclusions: Taking additional SCM during lumpectomy resulted in a significantly lower overall volume of breast tissue excised, with no increase in LRR. Contrary to prior studies, we found that SCM did not decrease re-excision rates or impact the success of BCT. Therefore, the main advantage of taking SCM appears to be that less breast tissue is excised, which could potentially improve cosmetic outcomes.

In vitro spine flexibility testing has been performed using a variety of laboratory-specific loading apparatuses and conditions, making test results across laboratories difficult to compare. The application of pure moments has been well established for spine flexibility testing, but to our knowledge there have been no attempts to quantify differences in range of motion (ROM) resulting from laboratory-specific loading apparatuses. Seven fresh-frozen lumbar cadaveric motion segments were tested intact at four independent laboratories. Unconstrained pure moments of 7.5 Nm were applied in each anatomic plane without an axial preload. At laboratories A and B, pure moments were applied using hydraulically actuated spinal loading fixtures with either a passive (A) or controlled (B) XY table. At laboratories C and D, pure moments were applied using a sliding (C) or fixed ring (D) cable-pulley system with a servohydraulic test frame. Three sinusoidal load-unload cycles were applied at laboratories A and B while a single quasistatic cycle was applied in 1.5 Nm increments at laboratories C and D. Non-contact motion measurement systems were used to quantify ROM. In all test directions, the ROM variability among donors was greater than single-donor ROM variability among laboratories. The maximum difference in average ROM between any two laboratories was 1.5° in flexion-extension, 1.3° in lateral bending and 1.1° in axial torsion. This was the first study to quantify ROM in a single group of spinal motion segments at four independent laboratories with varying pure moment systems. These data support our hypothesis that given a well-described test method, independent laboratories can produce similar biomechanical outcomes., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Pseudoarthrosis after pedicle subtraction osteotomy (PSO) can require revision surgery due to posterior rod failure, and the stiffness of these revision constructs has not been quantified., Objective: To compare the multidirectional bending stiffness of 7 revision strategies following rod failure., Methods: Seven fresh-frozen human spines (T11-pelvis) were tested as follows: (1) posterior instrumentation from T12-S1 (excluding L3) with iliac fixation and L3 PSO; (2) inline connectors after rod breakage at L3 (L2 screws removed for access); (3) cross-links connecting rods above and below inline connectors; satellite rods (4) parallel, (5) 45° anterior, and (6) 45° posterior to original rods; 45° posterior with cross-links connecting (7) original and (8) satellite rods. Groups 3 to 8 were tested in random order. Nondestructive pure moment flexion-extension (FE), lateral bending (LB), and axial rotation (AR) tests were conducted to 7.5 Nm; 3D motion tracking monitored the primary range of motion., Results: Addition of inline connectors alone restored stiffness in FE and LB (P > .05), but not in AR (P < .05). Satellite rods (groups 4 to 6) restored stiffness in FE and LB (P > .05), but not in AR (P < .05) and were not significantly different from one another (P > .05). The addition of cross-links (groups 3, 7, and 8) restored stiffness in all bending modes (P > .05) and were significantly greater than inline connectors alone in AR (P < .05)., Conclusion: The results suggest that these revision strategies can restore stiffness without entire rod replacement. Failure of AR stiffness restoration can be mitigated with cross-links. The positioning of the satellite rods is not an important factor in strengthening the revision.

Purpose: To investigate the mechanical properties of some common suture materials currently in use and compare them with a new multifilament stainless steel suture., Methods: We investigated the mechanical properties of 3-0 and 4-0 Fiberwire, 3-0 Supramid, 3-0 Ethibond, and a new 3-0 and 4-0 multifilament stainless steel suture. All suture material was tested in a knotted configuration and all but the Supramid was tested in an unknotted configuration. We measured the load, elongation at failure, and stiffness during both tests., Results: The 4-0 multifilament stainless steel showed the least elongation, whereas the 3-0 multifilament stainless steel withstood the highest load of any material in both the knotted and unknotted tests. There was no difference in stiffness between the 3-0 and 4-0 multifilament stainless steel when untied; however, the 3-0 multifilament stainless steel was stiffer when tied. Soaking in a saline solution had no significant effect on the ultimate load, elongation at failure, or stiffness of any of the sutures. The 3-0 Fiberwire and 3-0 Ethibond required at least 5 throws to resist untying., Conclusions: Multifilament stainless steel exhibited promising mechanical advantages over the other sutures tested. More research is needed to determine how this material will affect the clinical outcomes of primary flexor tendon repair., Clinical Relevance: With a secure attachment to the tendon, the multifilament stainless steel's lower elongation and better knot-holding ability may result in a higher force to produce a 2-mm gap and a higher ultimate tensile strength in a tendon repair., (Copyright © 2011 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

A series of potent phthalazinone-based human H(1) and H(3) bivalent histamine receptor antagonists, suitable for intranasal administration for the potential treatment of allergic rhinitis, were identified. Blockade of H(3) receptors is thought to improve efficacy on nasal congestion, a symptom of allergic rhinitis that is currently not treated by current antihistamines. Two analogues (56a and 56b) had slightly lower H(1) potency (pA(2) 9.1 and 8.9, respectively, vs 9.7 for the clinical gold-standard azelastine, and H(3) potency (pK(i) 9.6 and 9.5, respectively, vs 6.8 for azelastine). Compound 56a had longer duration of action than azelastine, low brain penetration, and low oral bioavailability, which coupled with the predicted low clinical dose, should limit the potential of engaging CNS-related side-effects associated with H(1) or H(3) antagonism.

Hypothesis: Scapular cortical thickness has not been fully characterized from the perspective of determining optimal screw placement for securing the glenoid base plate in reverse shoulder arthroplasty., Materials and Methods: Twelve fresh frozen cadaveric scapulae underwent high resolution CT scans with 3-dimensional reconstructions and wall thickness analysis. Digital base plates were positioned and virtual screws were placed according to 2 scenarios: A - intraosseous through the entire course and exits a "safe region" with no known neurovascular structures; B - may leave and re-enter the bone and penetrates the thickest cortical region accessible regardless of adjacent structures., Results: For scenario A, the optimal screw configurations were: (superior screw) length = 35 mm, 9° superior, 2° posterior; (inferior screw-A) length = 34 mm, 16° inferior, 5° anterior; (inferior screw-B) length = 31 mm, 31 inferior, 4 posterior; (posterior screw) length 19 mm, 29° inferior, 3° anterior. For scenario B: (superior screw) length = 36 mm, 28° superior, 10° anterior; (inferior screw) length = 35 mm, 19° inferior, 4° anterior; (posterior screw) length 37 mm, 23° superior, 3° anterior. The anterior screw was consistent between scenarios A and B, averaged 29 mm in length and was directed 16° inferior and 14° posterior., Conclusion: Thicker cortical regions were present in the lateral aspect of the suprascapular notch, scapular spine base, anterior/superior aspect of inferior pillar and junction of glenoid neck and scapular spine. Regions with high cortical thickness were accessible for both scenarios except for the posterior screw in scenario A., (Copyright © 2011 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Object: Ankylosing spondylitis (AS) is a genetic condition that frequently results in spinal sagittal plane deformity of thoracolumbar or cervicothoracic junctions. Generally, a combination of osteotomy and spinal fixation is used to treat severe cases. Although surgical techniques for traumatic injury across the cervicothoracic junction have been well characterized in clinical and biomechanical literature, the specific model of instrumented opening wedge osteotomy in autofused AS has not been studied biomechanically. This study characterizes the structural stability of various posterior fixation techniques across the cervicothoracic junction in spines with AS, specifically considering the effects of posterior rod diameter and material type., Methods: For each of 10 fresh-frozen human spines (3 male, 7 female; mean age 60 ± 10 years; C3-T6), an opening wedge osteotomy was performed at C7-T1. Lateral mass screws were inserted bilaterally from C-4 to C-6 and pedicle screws from T-1 to T-3. For each specimen, 3.2-mm titanium (Ti), 3.5-mm Ti, and 3.5-mm cobalt chromium (CoCr) posterior spinal fusion rods were tested. To simulate the anterior autofusion and long lever arms characteristic of AS, anterior cervical plates were placed from C-4 to C-7 and T-1 to T-3 using fixed angle screws. Nondestructive flexion-extension, lateral bending, and axial rotation tests were conducted to 3.0 Nm in each anatomical direction; 3D motion tracking was used to monitor primary range of motion across the osteotomy (C7-T1). Biomechanical tests used a repeat-measures test design. The order of testing for each rod type was randomized across specimens., Results: Constructs instrumented with 3.5-mm Ti and 3.5-mm CoCr rods were significantly stiffer in flexion-extension than those with the 3.2-mm Ti rod (25.2% ± 16.4% and 48.1% ± 15.3% greater than 3.2-mm Ti, respectively, p < 0.05). For axial rotation, the 3.5-mm Ti and 3.5-mm CoCr constructs also exhibited a significant increase in rigidity compared with the 3.2-mm Ti construct (36.1% ± 12.2% and 52.0% ± 20.0%, respectively, p < 0.05). There were no significant differences in rigidity seen between the 3 types of rods in lateral bending (p > 0.05). The 3.5-mm CoCr rod constructs showed significantly higher rigidity in flexion-extension than the 3.5-mm Ti rod constructs (33.1% ± 15.5%, p < 0.05). There was a trend for 3.5-mm CoCr to have greater rigidity in axial rotation (36.2% ± 18.6%), but this difference was not statistically significant (p > 0.05)., Conclusions: The results of this study suggest that 3.5-mm CoCr rods are optimal for achieving the most rigid construct in opening wedge osteotomy in the cervicothoracic region of an AS model. Rod diameter and material properties should be considered in construct strategy. Some surgeons have advocated anterior plating in patients with AS after osteotomy for additional stability and bone graft surface. Although this effect was not examined in this study, additional posterior stability achieved with CoCr may decrease the need for additional anterior procedures.

Hypothesis: Posterolateral rotatory instability (PLRI) of the elbow results from injury to the lateral collateral ligament complex from trauma or iatrogenic injury. The lateral pivot-shift test (PST) is standard for diagnosing PLRI, but its subjectivity affects diagnosis and makes it difficult to train young surgeons. A well-controlled investigation has not been done to quantify interclinician and intraclinician variability in PST mechanics in the intact and unstable elbow. The authors predict that there exist differences in PST mechanics between clinicians., Materials and Methods: Five unpaired elbow specimens underwent PST intact and after sequential sectioning of lateral stabilizing ligaments. Multiple PST trials were performed on each specimen by 3 clinicians (1 expert, 2 in-training) while 3-dimensional motion and loads were recorded. Intraclinician and interclinician variability were analyzed., Results: Mean supination torque, valgus torque, and axial force were 3.6 ± 1.9 Nm, 5.6 ± 3.1 Nm, and -8.3 ± 15.7 N, respectively. Mean radial head displacement was 13.7 ± 4.6 mm. There were no significant differences in these measures after sequential ligament sectioning. One surgeon (in-training 2) applied significantly greater axial compressive forces across the elbow joint (5-9 N difference). Variability of axial force (380% ± 473%) was greater than that of supination torque (20% ± 11%), valgus torque (14% ± 4%), and radial head displacement (8% ± 6%; P < .05 for analysis of variance)., Discussion: The clinicians performed the PST consistently and with comparable loads, with the exception of axial compressive force across the radiohumeral joint, which varied across clinicians by 1 to 2 pounds (5-9 N)., Conclusion: This study suggests that the PST is a mechanically reproducible clinical examination, despite differing levels of training in performing the maneuver. With the exception of axial force, PST mechanics are highly repeatable for a given surgeon applying the test on a single specimen., (Copyright © 2010 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)