Search

MotivationCells contain dozens of major organelles and thousands of other structures, many of which vary extensively in their number, size, shape and spatial distribution. This complexity and variation dramatically complicates the use of both traditional and deep learning methods to build accurate models of cell organization. Most cellular organelles are distinct objects with defined boundaries that do not overlap, while the pixel resolution of most imaging methods is not sufficient to resolve these boundaries. Thus while cell organization is conceptually object-based, most current methods are pixel-based. Using extensive image collections in which particular organelles were fluorescently-labeled, deep learning methods can be used to build conditional autoencoder models for particular organelles. A major advance occurred with the use of a U-net approach to make multiple models all conditional upon a common reference, unlabeled image, allowing the relationships between different organelles to be at least partially inferred.ResultsWe have developed improved GAN-based approaches for learning these models and have also developed novel criteria for evaluating how well synthetic cell images reflect the properties of real images. The first set of criteria measure how well models preserve the expected property that organelles do not overlap. We also developed a modified loss function that allows retraining of the models to minimize that overlap. The second set of criteria uses object-based modeling to compare object shape and spatial distribution between synthetic and real images. Our work provides the first demonstration that, at least for some organelles, deep learning models can capture object-level properties of cell images.AvailabilityA Reproducible Research Archive containing all source code, generated images and analysis results will be made available at http://murphylab.cbd.cmu.edu/Software upon publication.Contactmurphy@cmu.eduSupplementary informationSupplementary data are available at Bioinformatics online.

An automated image analysis pipeline to map cell geometry and basal body organization in the ciliate Tetrahymena thermophila is described. Generative modeling was used to computationally reconstruct cell cycle progression from images of cells at single time points. The results reveal novel aspects of basal body distribution and replication.

Dose Levels

Purpose: Our preclinical studies showed that the PARP inhibitor, olaparib, prior to carboplatin attenuated carboplatin cytotoxicity. We evaluated sequence-specific pharmacokinetic and pharmacodynamic effects, safety, and activity of the combination.Experimental Design: Eligible patients had metastatic or recurrent women's cancer. Olaparib tablets were introduced (100 or 200 mg twice daily, days 1–7) in a 3 + 3 dose escalation with carboplatin AUC4 or 5 every 21 days, up to eight cycles, followed by olaparib 300 mg twice daily maintenance. Patients were randomly assigned to starting schedule: cohort A (olaparib days 1–7, carboplatin on day 8) or B (carboplatin on day 1, olaparib days 2–8) during cycle 1. Patients received the reversed scheme in cycle 2. Blood was collected for olaparib pharmacokinetics, platinum–DNA adducts, comet assay, and PAR concentrations. The primary objectives were to examine schedule-dependent effects on olaparib pharmacokinetics and platinum–DNA adducts.Results: A total of 77 (60 ovarian, 14 breast, and 3 uterine cancer) patients were treated. Dose-limiting toxicity was thrombocytopenia and neutropenia, defining olaparib 200 mg twice daily + carboplatin AUC4 as the MTD. Olaparib clearance was increased approximately 50% when carboplatin was given 24 hours before olaparib. In vitro experiments demonstrated carboplatin preexposure increased olaparib clearance due to intracellular olaparib uptake. Quantities of platinum–DNA adducts were not different as a function of the order of drug administration. Responses included 2 CRs and 31 PRs (46%) with a higher RR in BRCA mutation carriers compared with nonmutation carriers (68% vs. 19%).Conclusions: Tablet olaparib with carboplatin is a safe and active combination. Carboplatin preexposure causes intracellular olaparib accumulation reducing bioavailable olaparib, suggesting carboplatin should be administered prior to olaparib. Clin Cancer Res; 23(6); 1397–406. ©2016 AACR.

Supplementary method 1. DNA platinum-adducts measurement

While many biological processes can be modeled by abstracting away the space in which those processes occur, some modeling (particularly at the cellular level) requires space itself to be modeled, with processes happening not in well-mixed compartments, but spatially-defined compartments. The SBML Level 3 Core specification does not include an explicit mechanism to encode geometries and spatial processes in a model, but it does provide a mechanism for SBML packages to extend the Core specification and add additional syntactic constructs. The SBML Spatial Processes package for SBML Level 3 adds the necessary features to allow models to encode geometries and other spatial information about the elements and processes it describes.

MotivationMultiplexed protein imaging methods provide valuable information on complex tissue structure and cellular heterogeneity. However, costs increase and image quality decreases with the number of biomarkers imaged, and the number of markers that can be measured in the same tissue sample is limited.ResultsIn this work, we propose an efficient algorithm to choose a minimal predictive subset of markers that for the first time allows the prediction of full images for a much larger set of markers. We demonstrate that our approach also outperforms previous methods for predicting cell-level marker composition. We also demonstrate that an effective minimal subset can be selected even if the desired full set is too large to be imaged on the same samples.AvailabilityAll code and intermediate results are available in a Reproducible Research Archive athttps://github.com/murphygroup/CODEXPanelOptimization.

Patients with early-onset scoliosis (EOS) and spasticity may receive treatment with an intrathecal baclofen pump. We assessed how baclofen pumps are associated with the odds of complications and secondary interventions after growth-friendly (GF) spine surgery for EOS and analyzed infectious complications within the pump cohort.Using a prospectively maintained, international multicenter database, we studied patients with neuromuscular EOS with baclofen pumps who underwent GF spine surgery from 2002 through 2019 (n=25). Baclofen pumps were implanted before GF instrumentation in 18 patients, during in 2 patients, and after in 5 patients. Patients with existing pumps at initial GF spine surgery were matched 1:3 with 54 patients (control group) without pumps according to treatment center, year of surgery, diagnosis, surgery type, and preoperative curve magnitude. Univariate analysis and multivariate logistic regression were performed to compare complications and secondary interventions between the 2 cohorts.Patients with baclofen pumps had 4.8 times the odds [95% confidence interval (CI): 1.5-16] of experiencing any complication within 1 year after initial GF spine surgery compared with controls. During mean follow-up of 6.9±4.3 years, they had 4.7 times the odds (95% CI: 1.3-16) of deep surgical site infection and 5.6 times the odds (95% CI: 1.2-26) of spinal rod removal after any complication. Differences in rates of mechanical complication, such as rod migration and breakage, were nonsignificant between the 2 groups. For the 9 patients (50%) with pumps who experienced infections, the most common microorganisms were Staphylococcus aureus (4 patients) and Pseudomonas aeruginosa (2). The pump/catheter was revised or removed, in addition to antibiotic therapy or surgical irrigation and debridement, in 2 patients.Among patients with neuromuscular EOS, those with baclofen pumps are much more likely to experience complications within 1 year after GF spine surgery. They are also more likely to have deep surgical site infections, with S. aureus and P. aeruginosa being the most common causative organisms, and to require spinal rod removal.Level III-retrospective comparative study.

Objective To evaluate institutional opioid prescribing patterns following percutaneous fixation of pediatric supracondylar humerus fractures before and after implementation of a standardized discharge order set. Design A retrospective review of patients who underwent closed reduction and percutaneous skeletal fixation of a Type II or III supracondylar humerus fracture in 2017 (prior to pain protocol implementation) and again in 2019 (after pain protocol implementation) Setting Single Tertiary Care Children's Hospital Participants In total, 106 patients met inclusion criteria between years 2017 (n = 49) and 2019 (n = 57). Exclusion criteria included miscoded patients, open fractures, patients who presented with vascular injury or nerve palsy, polytrauma patients with multiple fractures in the same upper extremity, and supracondylar humerus fractures that underwent an open procedure. Results There were no significant differences between inpatient pain scores (p = 0.91) and MDE prescribed (p = 0.75) between the 2 cohorts. In 2017, large variability was noted in day supply of opioids (0-11.4 days) and MDE (0-8.45 mg/kg), with significant differences between prescribing patterns of junior and senior level residents (mean day supply of opioids (p = 0.045), mean MDE prescribed on discharge (p = 0.001)). After implementation of a standardized opioid discharge order set, there was a tenfold increase in the number of patients discharged without an opioid prescription (2017: 4%, 2019: 44%). Additionally, any discrepancies between prescribing practices of junior and senior level residents were eliminated (mean day supply of opioids (p = 0.65), mean MDE prescribed on discharge (p = 0.69)). Conclusions The introduction of a standardized post-operative opioid discharge order set led to a 10-fold increase in the number of patients discharged without an opioid prescription. Additionally, the order set decreased the variability in the prescribing patterns of discharge opioid medications without change in pain control. The resident prescribing variability based upon level of experience resolved with the use of the order set.

Because of the relative rarity of Early Onset Scoliosis (EOS) cases, patient registries were developed to combine clinical information from multiple institutions to maximize patient care and outcomes. This study examines the history and trends regarding the use of growth-friendly devices for index surgical procedures in EOS patients within the Pediatric Spine Study Group database.All index growth-friendly implants were queried from registry inception until October 2020. EOS etiology, device/implant type, and geographic area/institution for each procedure were recorded.From 1994 to 2020, 2786 patients underwent index surgery at a mean age of 6.2±2.9 years. There were 908 traditional growing rods (TGR) (32.3%), 922 vertical expandable prosthetic titanium rib devices (VEPTR) (33.1%), 5 hybrid VEPTR/TGR (0.18%), and 951 magnetically controlled growing rods (MCGR) (34.2%) index implants. Fifty-six different institutions reported an index implant, and 5 accounted for 823 (30%) of the cases during the study period. Institutions in the Northeast accounted for more index implants than other regions of the United States. There was a 40% increase in index implant insertions annually when comparing 1994 (3 implants/1 center) to 2018 (234 implants/56 centers), ( P0.001). Beginning in 2009, there was a 90.9% decrease in the number of TGR/VEPTR procedures (2009: 156 implants/32 centers; 2019: 22 implants/49 centers P =0.001), and a 479% increase in MCGR (2009: 1 implant/1 center; 2018: 197 implants/34 centers ( P =0.005). The overall number of growth-friendly index procedures performed in 2019 (150/49 centers) decreased 34.5% when compared to 2018 (234/48 centers).The number of growth-friendly implants reported in the Pediatric Spine Study Group registry as the initial surgical management of EOS increased markedly over the past 20 years. MCGR is currently the predominant type of device utilized for index surgical procedures by group members, surpassing the use of VEPTR and TGR in 2014. There was a significant decrease in index growth-friendly procedures in 2019 compared to 2018.Level IV.

Accessory ossicles are a common radiographic finding about the foot and ankle in children and adolescents. They are often noted incidentally during evaluation of foot and ankle injuries, and most can be managed nonsurgically. Although over 20 accessory ossicles have been described around the foot and ankle, five specific structures generate the most concern in pediatric patients. An accessory navicular presents commonly with medial midfoot pain and may require surgical intervention after failure of nonsurgical treatment. Although an accessory navicular can be treated surgically with simple excision, there is some recent evidence that supports concomitant reconstruction of associated flatfoot deformities. Os trigonum, an ossicle posterior to the talus, is also commonly asymptomatic. However, os trigonum may be associated with persistent posterior ankle pain, and open and endoscopic resection techniques are successful. Os subfibulare is an uncommon ossicle that may be associated with recurrent ankle sprains. Recent literature reports successful return to activities after ossicle excision and ligament reconstruction. Os subtibiale may be confused with a medial malleolar fracture in skeletally immature patients. Os peroneum may contribute to lateral midfoot pain.

OBJECTIVEAlthough the advent of magnetic growing rod technology for scoliosis has provided a means to bypass multiple hardware lengthening operations, it is important to be aware that many of these same patients have a codiagnosis of hydrocephalus with magnet-sensitive programmable ventricular shunts. As the magnetic distraction of scoliosis rods has not previously been described to affect the shunt valve setting, the authors conducted an investigation to characterize the interaction between the two devices.METHODSIn this ex vivo study, the authors carried out 360 encounters between four different shunt valve types at varying distances from the magnetic external remote control (ERC) used to distract the growing rods. Valve settings were examined before and after every interaction with the remote control to determine if there was a change in the setting.RESULTSThe Medtronic Strata and Codman Hakim valves were found to have setting changes at distances of 3 and 6 inches but not at 12 inches. The Aesculap proGAV and Codman Certas valves, typically described as MRI-resistant, did not have any setting changes due to the magnetic ERC regardless of distance.CONCLUSIONSAlthough it is not necessary to check a shunt valve after every magnetic distraction of scoliosis growing rods, if there is concern that the magnetic ERC may have been within 12 inches (30 cm) of a programmable ventricular shunt valve, the valve should be checked at the bedside with a programmer or with a skull radiograph along with postdistraction scoliosis radiographs.

Increasingly, patients with early onset scoliosis (EOS) are completing a growth friendly surgical program followed by observation, removal of implants or a definitive spinal fusion. These patients are colloquially referred to as “graduates”. A standardized definition of a graduate is needed for research and comparing the outcomes, family counseling, and a better understanding of the population. A 15-question electronic survey was completed by 39 experienced pediatric spine surgeons to identify factors salient to the definition of a graduate of EOS surgical programs. A Delphi/Nominal group technique session with nine questions was then performed face-to-face with 21 members of the Pediatric Spine Study Group to discuss and refine the definition. A follow-up electronic survey was then distributed to these same 21 members to gain consensus on the final definition. From the initial survey, it was identified that a graduate did not require definitive spinal fusion after a growing program. From the Delphi session, it was determined that skeletal maturity was the most important factor in defining a graduate. A strictly defined minimum length of follow-up was not felt to be a prerequisite for qualification of graduation. After the final electronic version was distributed, > 80% of respondents agreed upon the final definition, thereby achieving consensus. The Pediatric Spine Study Group recommends adoption of the following definition: a “graduate” is a patient who has undergone any surgical program to treat early onset scoliosis, and has reached skeletal maturity and does not have a planned surgical intervention for EOS in the future. V.

A major challenge for protein databases is reconciling information from diverse sources. This is especially difficult when some information consists of secondary, human-interpreted rather than primary data. For example, the Swiss-Prot database contains curated annotations of subcellular location that are based on predictions from protein sequence, statements in scientific articles, and published experimental evidence. The Human Protein Atlas (HPA) consists of millions of high-resolution microscopic images that show protein spatial distribution on a cellular and subcellular level. These images are manually annotated with protein subcellular locations by trained experts. The image annotations in HPA can capture the variation of subcellular location across different cell lines, tissues, or tissue states. Systematic investigation of the consistency between HPA and Swiss-Prot assignments of subcellular location, which is important for understanding and utilizing protein location data from the two databases, has not been described previously. In this paper, we quantitatively evaluate the consistency of subcellular location annotations between HPA and Swiss-Prot at multiple levels, as well as variation of protein locations across cell lines and tissues. Our results show that annotations of these two databases differ significantly in many cases, leading to proposed procedures for deriving and integrating the protein subcellular location data. We also find that proteins having highly variable locations are more likely to be biomarkers of diseases, providing support for incorporating analysis of subcellular location in protein biomarker identification and screening.

Introduction After discontinuation of growth friendly (GF) surgery for early onset scoliosis, patients undergo spinal fusion or continued observation. This last planned treatment is colloquially called "definitive" treatment, conferring these patients as "graduates" of a growing program. The 5-year radiographic and clinical outcomes of this cohort are unknown. Methods An international pediatric spine database was queried for patients from a GF program (spine or rib-based) with minimum 5-year follow-up from last planned surgery (GF or spinal fusion). Radiographs and charts were reviewed for main coronal curve angle and maximum kyphosis as well as occurrence of secondary surgery. Results Of 580 graduates, 170 (29%) had minimum 5-year follow-up (37% male). Scoliosis etiology was congenital in 41 (24%), idiopathic 36 (21%), neuromuscular 51 (30%), and syndromic 42 (25%). Index surgery consisted of spine-based growing rods in 122 (71%) and rib-based distraction in 48 (29%). Mean age at index surgery was 6.8 years, and patients underwent an average of 5.4 lengthenings over an average of 4.9 years (range, 6 mo to 11 y). Last planned treatment was at an average age of 11.8 years (range, 7 to 17 years). Last planned treatment consisted of spinal fusion in 114 patients, 47 had growing implants maintained, 9 had implants removed. Average follow-up was 7.3 years (range, 5 to 13 y).When compared from postdefinitive treatment to 2-year follow-up, there was noted progression of the coronal curve angle (46±19 to 51±21 degrees, P=0.046) and kyphosis (48±20 to 57±25 degrees, P=0.03). However, between 2 and 5 years, no further progression occurred in the coronal (51±21 to 53±21 degrees, P=0.26) or sagittal (57±25 to 54±28 degrees, P=0.93) planes. When stratified based on etiology, there was no significant coronal curve progression between 2- and 5-year follow-up. When comparing spinal fusion patients to those who had maintenance of their growing construct, there was also no significant curve progression.Thirty-seven (21%) underwent at least 1 (average, 1.7; range, 1 to 7) revision surgery following graduation, and 15 of 37 (41%) underwent 2 or more revision surgeries. Reason for revision was implant revision (either GF or spinal fusion) in 34 patients, and implant removal in 3. On an average, the first revision was 2.5 years after the definitive treatment plan (range, 0.02 to 7.4 y). In total, 15 of 37 (41%) revisions occurred over 2 years following the final decision for treatment plan, and 7 of 37 (19%) occurred 5 or more years after the definitive treatment.Patients who underwent spinal fusion as a definitive treatment strategy were more likely to undergo revision surgery (27%) than patients who had their GF implants maintained (11%) (P=0.04). Conclusions Five years following "graduation" from growing surgery for early onset scoliosis, there is progression of curve magnitude in both the coronal and sagittal planes up to 2 years, with no further progression at 5 years. A total of 21% of patients undergo at least 1 revision surgery, and average time to revision surgery is over 2 years from last planned surgery. Risk of revision surgery was higher in patients who underwent a spinal fusion as their definitive treatment strategy. Level evidence Level III-retrospective comparative. Type of evidence Therapeutic.

INTRODUCTION Pediatric venous thromboembolism (VTE) is a concern for orthopaedic surgeons. We sought to query the Pediatric Orthopaedic Society of North America (POSNA) members on current VTE prophylaxis practice and compare those results with those of a previous survey (2011). METHODS A 35-question survey was emailed to all active and candidate POSNA members. The survey consisted of questions on personal and practice demographics; knowledge and implementation of various VTE prophylaxis protocols, mechanical and chemical VTE prophylaxis agents, and risk factors; and utilization of scenarios VTE prophylaxis agents for various clinical scenarios. One- and two-way frequency tables were constructed comparing results from the current survey and those of the 2011 survey. RESULTS Two hundred thirty-nine surveys were completed (18% respondent rate), with most respondents from an academic/university practice reporting one or two partners (>60%). Half were in practice ≥15 years, and >90% reported an almost exclusive pediatric practice. One-third of the respondents reported familiarity with their institution-defined VTE prophylaxis protocol, and 20% were aware of an institutionally driven age at which all patients receive VTE prophylaxis. The most frequently recognized risk factors to guide VTE prophylaxis were oral contraceptive use, positive family history, and obesity. Respondents indicated a similar frequency of use of a VTE prophylaxis agent (either mechanical or chemical) for spinal fusion, hip reconstruction, and trauma (60% to 65%), with lower frequency for neuromuscular surgery (34%) (P < 0.001). One hundred thirty-seven respondents had a patient sustain a deep vein thrombosis, and 66 had a patient sustain a pulmonary embolism. Compared with responses from 2011, only 20 more respondents reported familiarity with their institution VTE prophylaxis protocol (75 versus 55). In 2018, aspirin was used more frequently than in 2011 (52% versus 19%; P < 0.0001) and enoxaparin was used less frequently (20% versus 41%; P < 0.0001). DISCUSSION Over the past 7 years since the first POSNA survey on VTE prophylaxis, most POSNA members are still unaware of their institution specific VTE prophylaxis protocol. Most respondents agree that either mechanical or chemical VTE prophylaxis should be used for spinal fusion, hip reconstruction, and trauma. The use of aspirin as an agent of chemical VTE prophylaxis has increased since 2011. LEVEL OF EVIDENCE Level IV. Type of evidence: therapeutic.

PC12 cells are a popular model system to study changes driving and accompanying neuronal differentiation. While attention has been paid to changes in transcriptional regulation and protein signaling, much less is known about the changes in organization that accompany PC12 differentiation. Fluorescence microscopy can provide extensive information about these changes, although it is difficult to continuously observe changes over many days of differentiation. We describe a generative model of differentiation-associated changes in cell and nuclear shape and their relationship to mitochondrial distribution constructed from images of different cells at discrete time points. We show that the model accurately represents complex cell and nuclear shapes and learn a regression model that relates cell and nuclear shape to mitochondrial distribution; the predictive accuracy of the model increases during differentiation. Most importantly, we propose a method, based on cell matching and interpolation, to produce realistic simulations of the dynamics of cell differentiation from only static images. We also found that the distribution of cell shapes is hollow: most shapes are very different from the average shape. Finally, we show how the method can be used to model nuclear shape changes of human-induced pluripotent stem cells resulting from drug treatments.

At some point after children with early-onset scoliosis (EOS) undergo implantation of a distraction construct to control deformity and promote growth, a decision is made to discontinue lengthening. The purpose of this study was to evaluate surgeon indications for discontinuation of a lengthening program and to evaluate patient outcomes. As a part of a multicenter database, surgeons prospectively completed a questionnaire at the completion of growth-friendly treatment. Surgeon indications for discontinuation included patient age, pain/functional status, implant status, and spinal deformity parameters. Patient demographics, scoliosis type, deformity parameters, and length of time in a growing program were queried. Patients were treated with a final fusion or observation, and rate of secondary surgeries was analyzed. Questionnaires were completed on 121 patients (61% female). EOS etiology was 31% neuromuscular, 43% congenital, 16% idiopathic, and 10% syndromic. Average age at initiation of growing program was 6.8 ± 3.1 years, and average age at discontinuation was 12.7 ± 2.5 years. The most commonly cited indications for discontinuation of a lengthening program included bone age/skeletal maturity (n = 46), patient age (n = 33), and diminishing returns with expansions (n = 33). A larger coronal Cobb angle was found in patients who underwent definitive fusion (65°) when compared with continued observation (55°, p = 0.001). Twenty-nine (24%) patients were initially treated with observation after completion of a growing construct. In this subgroup, at a minimum of 2 years’ (average 3.8 years’) follow-up, 26/29 (90%) patients remained stable with observation alone; whereas, three (10%) underwent delayed final fusion surgery. The most common surgeon-cited indications for discontinuation of a lengthening program in EOS patients are skeletal maturity and patient age. The majority of patients (76%) underwent definitive spinal fusion after discontinuation of a lengthening program; whereas, those treated with observation alone had a survivorship of 90% at a minimum follow-up of two years.

In juvenile and adolescent tibia vara patients with sufficient growth remaining, implant-controlled hemiepiphyseodesis, or guided growth, can be used to correct deformity. Recent reports have described hardware failure of certain hemiepiphyseodesis implants in overweight patients with tibia vara. We describe our experience using transphyseal screws to correct deformity in this patient population.A retrospective chart and radiograph review was conducted on all juvenile and adolescent tibia vara patients who underwent lateral proximal tibial hemiepiphyseodesis using a single transphyseal screw. Charts were queried for preoperative and postoperative mechanical axis deviation, medial proximal tibial angle, lateral distal femoral angle, and postoperative complications or need for further surgery.In total, 14 affected limbs in 9 patients (6 males) who underwent lateral proximal tibial transphyseal screw hemiepiphyseodesis were considered. Average chronologic age at implantation was 10.4 years and average body mass index was 31.7 kg/m. At average 23-month follow-up, the average mechanical axis deviation improved from 46 to 0 mm (P0.001), and the average medial proximal tibial angle improved from 81 to 92 degrees (P0.001). No limbs underwent further surgery to correct residual deformity. There were no complications or instances of implant failure associated with the transphyseal screws.Hemiepiphyseodesis using transphyseal screws is an effective technique to correct deformity in juvenile and adolescent tibia vara patients with sufficient growth remaining. This method can be used safely with few complications and with minimal risk of mechanical failure, even in overweight patients.Level IV-therapeutic.

Objective/Background: No studies to date have evaluated the the effect of rib-based anchors on the translational relationship between the rib and spine. We hypothesized that there would be an increase in the translational distance between the rib anchor and anterior vertebral body in early onset spinal deformity patients managed with long-term rib-based anchors. Methods: All patients with EOSD from a single tertiary level institution treated with a growth-friendly technique surgery utilizing proximal rib-based anchors from 2006-2015 with a minimum of 2-year follow-up were included. Thoracic kyphosis and the translational distance from the rib anchor to the corresponding anterior vertebral body were measured. Results: Twenty-seven patients (13 female, 14 male) qualified for inclusion. Mean age at implantation of the index proximal rib-based construct was 5±1.9 years (range, 1-9). EOSD etiology was congenital: 3, neuromuscular: 17, syndromic: 3, and idiopathic: 4. Mean kyphosis improved from 31±33° preoperatively to 25±20° immediately post-operatively. No significant changes in kyphosis were noted over 1 and 2 year follow-up (p=0.3). Twenty-one (78%) patients demonstrated an increase in translational distance from the rib anchors to the adjacent anterior vertebral body. Immediately post-operatively, mean distance was 25±1 mm and increased at 1-year (26±1 mm) and significantly at 2-year (29±1 mm) follow-up (p=0.005). Conclusion: The use of long term rib-based anchors may lead to an increase in the distance between the rib utilized for proximal fixation and the associated vertebral body, generating what appears to be increased anterior translation of the spine. This translation, in conjunction with increased or increasing overall thoracic kyphosis, may be the source of unexpected obstacles at the time of future surgical procedures for revision or final fusion.

The purpose of this study was to describe contraindications to the magnetically controlled growing rod (MCGR) in patients with early onset scoliosis (EOS) by establishing consensus amongst expert surgeons who treat these patients frequently.Nine pediatric spine surgeons from an international EOS study group participated in semi-structured interviews via email to identify factors that influence decision making in the use of MCGR. A 39-question survey was then developed to specify these factors as contraindications for MCGR-these included patient age and size, etiology, medical comorbidities, coronal and sagittal curve profiles, and skin and soft tissue characteristics. Pediatric spine surgeons from the EOS international study group were invited to complete the survey. A second 29-item survey was created to determine details and clarify results from the first survey. Responses were analyzed for consensus ( 70%), near consensus (60-69%), and no consensus/variability ( 60%) for MCGR contraindication.56 surgeons of 173 invited (32%) completed the first survey, and 64 (37%) completed the second survey. Responders had a mean of over 15 years in practice (range 1-45) with over 6 years of experience with using MCGR (range 2-12). 71.4% of respondents agreed that patient size characteristics should be considered as contraindications, including BMI (81.3%) and spinal height (84.4%), although a specific BMI range or a specific minimum spinal height were not agreed upon. Among surgeons who agreed that skin and soft tissue problems were contraindications (78.6%), insufficient soft tissue (98%) and skin (89%) to cover MCGR were specified. Among surgeons who reported curve stiffness as a contraindication (85.9%), there was agreement that this curve stiffness should be defined by clinical evaluation (78.2%) and by traction films (72.3%). Among surgeons who reported sagittal curve characteristics as contraindications, hyperkyphosis (95.3%) and sagittal curve apex above T3 (70%) were specified. Surgeons who indicated the need for repetitive MRI as a contraindication (79.7%) agreed that image quality (72.9%) and not patient safety (13.6%) was the concern. In the entire cohort, consensus was not achieved on the following factors: patient age (57.4%), medical comorbidities (46.4%), etiology (53.6%), and coronal curve characteristics (58.9%).Surgeon consensus suggests that MCGR should be avoided in patients who have insufficient spinal height to accommodate the MCGR, have potential skin and soft tissue inadequacy, have too stiff a spinal curve, have too much kyphosis, and require repetitive MRI, particularly of the spine. Future data-driven studies using this framework are warranted to generate more specific criteria (e.g. specific degrees of kyphosis) to facilitate clinical decision making for EOS patients.Level V-expert opinion.

Cell segmentation is a cornerstone of many bioimage informatics studies and inaccurate segmentation introduces error in downstream analysis. Evaluating segmentation results is thus a necessary step for developing segmentation methods as well as for choosing the most appropriate method for a particular type of sample. The evaluation process has typically involved comparison of segmentations to those generated by humans, which can be expensive and subject to unknown bias. We present here an approach to evaluating cell segmentation methods without relying upon comparison to results from humans. For this, we defined a number of segmentation quality metrics that can be applied to multichannel fluorescence images. We calculated these metrics for 14 previously-described segmentation methods applied to datasets from 4 multiplexed microscope modalities covering 5 tissues. Using principal component analysis to combine the metrics we defined an overall cell segmentation quality score and ranked the segmentation methods. We found that two deep learning-based methods performed the best overall, but that results for all methods could be significantly improved by postprocessing to ensure proper matching of cell and nuclear masks. Our evaluation tool is available as open source and all code and data are available in a Reproducible Research Archive.

A previous study showed that patients with neuromuscular scoliosis who underwent fusion to L5 had excellent coronal curve correction and improvement in pelvic obliquity (PO) when preoperative L5 tilt was 15°. Our purpose was to identify indications to exclude the pelvis in children with cerebral palsy (CP) scoliosis treated with growing-friendly instrumentation.In a retrospective cohort study, children with CP scoliosis treated with TGR, MCGR, or VEPTR with minimum 2-year follow-up were identified from a multicenter database.27 patients with distal spine anchors (DSA) and 71 patients with distal pelvic anchors (DPA) placed at the index surgery were analyzed. The DSA group had a lower pre-index PO (9° vs 16°, P = 0.0001). Most recent radiographic data were similar except the DSA patients had a smaller major curve (47° vs 58°, P = 0.038). 6 (22%) DSA patients underwent extension of the instrumentation to the pelvis (DSA-EXT), most commonly at final fusion (5 patients). DSA-EXT patients had a higher pre-index L5 tilt than patients who did not require extension (DSA-NO EXT) (19° vs 10°, P = 0.009). Sub-analysis showed a lower major curve at most recent follow-up in the DSA-EXT group compared to the DPA group (33° vs 58°, P = 0.021). The DSA-EXT group had a higher number of complications per patient compared to the DSA-NO EXT group (2.3 vs 1.1, P = 0.029).Pre-index L5 tilt ≤ 10° and PO 10° may be indications to exclude the pelvis in children with CP scoliosis treated with growth-friendly instrumentation. DSA may provide better long-term control of the major curve than DPA.

BACKGROUND Obesity rates continue to rise among children and adolescents across the globe. A multicenter research consortium composed of institutions in the Southern US, located in states endemic for childhood obesity, was formed to evaluate the effect of obesity on pediatric musculoskeletal disorders. This study evaluates the effect of body mass index (BMI) percentile and socioeconomic status (SES) on surgical site infections (SSIs) and perioperative complications in patients with adolescent idiopathic scoliosis (AIS) treated with posterior spinal fusion (PSF). METHODS Eleven centers in the Southern US retrospectively reviewed postoperative AIS patients after PSF between 2011 and 2017. Each center contributed data to a centralized database from patients in the following BMI-for-age groups: normal weight (NW, 5th to

Introduction: Surgical Site Infection (SSI) is a rare but serious complication following Posterior Spinal Fusion (PSF) for pediatric scoliosis. Several studies have identified patient risk factors for SSI following PSF, including high Body Mass Index (BMI). The purpose of this study was to determine whether Radiographic Skin-to-spine Distance (RSD) can be used as a surrogate for BMI when evaluating the pediatric patient’s risk of developing a SSI after PSF. Methods: This study was performed retrospectively and included patients ages 0-18 who underwent PSF for scoliosis over a four-year period. RSD, defined as the distance from the L5 spinous process to the skin, was measured using preoperative lateral radiographs. Results: Of the 176 included patients, we identified eight (4.5%) who suffered from surgical site infection following PSF. Logistic regression analysis revealed no statistically significant predictors for SSI. However, there was a strong, statistically significant linear regression prediction between RSD and BMI (r = 0.71, p=0.001). Discussion: RSD was not shown to be predictive of SSI in this patient cohort. However, the strong correlation found between RSD and BMI suggests that when assessing risk of SSI, RSD may be useful as a substitute for BMI when BMI cannot be easily ascertained.

The purpose of this study was to compare the efficacy of a single-sugar-tong splint (SSTS) to a long-arm cast (LAC) in maintaining reduction of pediatric forearm fractures, while avoiding secondary intervention. One hundred patients age 3-15 with a forearm fracture requiring a reduction and immobilization were evaluated (50 LAC and 50 SSTS). Medical records and radiographs were reviewed at injury, postreduction, and at 1, 2, and 4 weeks postinjury. Sagittal and coronal angular deformities were recorded. Any secondary intervention due to loss of reduction was documented. The groups were matched by age (P = 0.19), sex (P = 0.26), mechanism of injury (P = 0.66), average injury sagittal deformity (LAC 27.4°, SSTS 25.4°; P = 0.50), and average injury coronal deformity (LAC 15.5°, SSTS 16°; P = 0.80) At 4 weeks postinjury follow-up, there were no statistically significant differences between use of an SSTS or LAC when comparing postimmobilization sagittal alignment (LAC 10.3 ± 7.2, SSTS 8.4 ± 5.1°; P = 0.46), coronal alignment (LAC 6.9 ± 4.6, SSTS 7.6 ± 9.3°; P = 0.46), or need for repeat manipulation or surgery (LAC 4/50, SSTS 3/50; P = 0.70).

A 9-year-old boy sustained an ulnohumeral dislocation with a medial epicondyle fracture and experienced incomplete post-traumatic median nerve palsy in addition to post-traumatic stiffness following closed reduction and cast immobilization. When his motor palsy and stiffness did not improve, MRI and ultrasound were obtained, which demonstrated entrapment of the median nerve in an osseous tunnel at the fracture site, compatible with type 2 median nerve entrapment. Subsequently, the patient underwent surgery to mobilize the medial epicondyle and free the median nerve, resulting in improved range of motion, near complete restoration of motor function, and complete restoration of sensory function in the median nerve distribution within 6 months of surgery. Median nerve entrapment, particularly intraosseous, is a rare complication of posterior elbow dislocation and medial epicondyle fracture that may result in significant, sometimes irreversible, nerve damage if there is a delay in diagnosis and treatment. A high degree of clinical suspicion with early imaging is indicated in patients with persistent stiffness or nerve deficits following reduction of an elbow dislocation. Intra-articular entrapment diagnosed on ultrasound has been reported and intraosseous entrapment diagnosed clinically and on MR neurography have been reported; however, to our knowledge, this is the first reported case of intraosseous (type 2) median nerve entrapment clearly visualized and diagnosed on traditional MRI and ultrasound. The use of ultrasound for diagnosing median nerve entrapment is an accurate, accessible, and non-invasive imaging option for patients presenting with suspected nerve entrapment following elbow dislocation.

The frequency of knee arthroscopy procedures is increasing in pediatric and adolescent patients. In general, complications after these procedures in adolescents are uncommon. The purposes of this study are to report the incidence of venous thromboembolism (VTE) in adolescent patients after knee arthroscopy procedures, as well identify risk factors in this patient population.Medical records were reviewed in all pediatric and adolescent patients (≤19 y) who underwent an arthroscopic knee procedure from 2010 to 2014 and were diagnosed with a symptomatic VTE in the postoperative period. Demographic features were recorded, and included age, sex, body mass index, clinical characteristics (diagnosis, type of surgical intervention, tourniquet time), VTE risk factors [family history of VTE, obesity (body mass index30), oral contraceptive use, and smoking use/exposure] and treatment (anticoagulation type/duration).Out of 2783 patients who underwent knee arthroscopy during the 5-year study period, 7 patients (3 males, 4 females, mean age, 16.9 y, range, 15 to 18) developed a symptomatic postoperative VTE (incidence, 0.25%, 95% confidence interval, 0.11%-0.54%). There were 6 unilateral deep venous thrombosis, and 1 bilateral deep venous thrombosis. Arthroscopic procedures performed in this cohort included anterior cruciate ligament reconstruction (3), isolated lateral release (1), meniscectomy (2), and patellar realignment with arthroscopic lateral release, open tibial tubercle osteotomy, and open proximal medial retinacular reefing (1). VTE was diagnosed an average of 9 days following surgery (range, 3 to 16). All patients were initially treated with low-molecular-weight heparin, and 2 were converted to warfarin. Mean duration of anticoagulation treatment was 64 days (range, 28 to 183). All patients had at least 1 identifiable medical or surgical risk factor, including oral contraceptive use (2), smoking (2), obesity (2), an arthroscopically assisted open procedure (4), or tourniquet time60 minutes (3).VTE after adolescent knee arthroscopy has not been well described. The incidence is ∼0.25%. Previously established risk factors for VTE were present in 100% of the affected population. Low-molecular-weight heparin was used to successfully treat this complication.Level IV.

Displaced pediatric forearm fractures often are treated with closed reduction and immobilization. Recent literature demonstrates no difference in maintaining alignment or needing repeat intervention in patients immobilized with either a single sugar-tong splint or a long-arm cast, but most series include patients with distal fractures. This study included patients 3 to 15 years old who underwent closed reduction and immobilization for displaced midshaft or proximal forearm fractures. Radiographs from the time of injury, after reduction, and at 4-week follow-up were reviewed for coronal and sagittal plane angular alignment. Secondary interventions also were recorded. A total of 121 patients (70 long-arm cast, 51 simple sugar-tong splint) met inclusion criteria. Groups were matched in terms of age ( P =.95), sex ( P =.41), body mass index ( P =.12), and angular deformity prior to reduction in the sagittal ( P =.78) and coronal ( P =.83) planes. Following closed reduction, sagittal ( P =.003) and coronal ( P =.002) alignment improved significantly in all patients. At 4-week follow-up, there were no significant differences in sagittal ( P =.15) or coronal ( P =.68) alignment between the 2 groups. Nine patients underwent a secondary intervention after the index reduction (long-arm cast, n=7; simple sugar-tong splint, n=2), with no statistically significant difference between groups ( P =.30). There were no statistically significant differences between patients managed with long-arm cast or simple sugar-tong splint regarding residual sagittal or coronal plane deformity at 4-week follow-up or incidence of secondary intervention. These findings indicate simple sugar-tong splint and long-arm cast appear to be acceptable and equivalent methods of immobilization for these injuries. [ Orthopedics . 2021;44(2):e178–e182.]

A 13-year-old obese boy presented with an acute-on-chronic unstable left slipped capital femoral epiphysis (SCFE). He underwent in situ surgical fixation with two 6.5-mm fully threaded cannulated screws. At 6 months, he presented with mechanical failure of both screws. He underwent screw removal, revision in situ fixation, a peritrochanteric flexion and internal rotational osteotomy, and an open femoroplasty. The osteotomy healed at 6 weeks. The femoral physis took an additional year to close.This case highlights an uncommon complication of in situ pinning of SCFE, discusses revision fixation options, and suggests possible prolonged physeal closure in severe slips.

Disk space infection (discitis) is an uncommon source of back pain in children. It occurs most frequently in children 1–5 years of age. Signs and symptoms may include back pain, abdominal pain, lethargy, and gait alterations. The non-specific nature of these findings may result in delayed presentation to a medical professional and subsequent diagnosis. Management predominantly includes antibiotic therapy, although short-term immobilization may be recommended in some cases. Biopsy or other surgical interventions are rarely indicated. Long-term sequelae, beyond radiographic changes, especially loss of disc space, are infrequent.

Most of the fascinating phenomena studied in cell biology emerge from interactions among highly organized multi-molecular structures embedded into complex and frequently dynamic cellular morphologies. For the exploration of such systems, computer simulation has proved to be an invaluable tool, and many researchers in this field have developed sophisticated computational models for application to specific cell biological questions. However, it is often difficult to reconcile conflicting computational results that use different approaches to describe the same phenomenon. To address this issue systematically, we have defined a series of computational test cases ranging from very simple to moderately complex, varying key features of dimensionality, reaction type, reaction speed, crowding, and cell size. We then quantified how explicit spatial and/or stochastic implementations alter outcomes, even when all methods use the same reaction network, rates, and concentrations. For simple cases we generally find minor differences in solutions of the same problem. However, we observe increasing discordance as the effects of localization, dimensionality reduction, and irreversible enzymatic reactions are combined. We discuss the strengths and limitations of commonly used computational approaches for exploring cell biological questions and provide a framework for decision-making by researchers developing new models. As computational power and speed continue to increase at a remarkable rate, the dream of a fully comprehensive computational model of a living cell may be drawing closer to reality, but our analysis demonstrates that it will be crucial to evaluate the accuracy of such models critically and systematically.