Perioperative multimodal analgesic injection for patients with adolescent idiopathic scoliosis undergoing posterior spinal fusion surgery.

PURPOSE: This retrospective cohort study compared postoperative as-needed (PRN) opioid consumption pre and postimplementation of a perioperative multimodal analgesic injection composed of ropivacaine, epinephrine, ketorolac, and morphine in patients undergoing posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). Secondary outcomes include pain score measurements, time to ambulation, length of stay, blood loss, 90-day complication rate, operating room time, nonopioid medication usage, and total inpatient medication cost before and after the initiation of this practice. METHODS: Consecutive patients weighing ≥ 20 kg who underwent PSF for a primary diagnosis of AIS between January 2017 and December 2020 were included. Data from 2018 were excluded to account for standardization of the practice. Patients treated in 2017 only received PCA. Patients treated in 2019 and 2020 only received the injection. Excluded were patients who had any diagnoses other than AIS, allergies to any of the experimental medications, or who were nonambulatory. Data were analyzed utilizing the two-sample t-test or Chi-squared test as appropriate. RESULTS: Results of this study show that compared with 47 patients treated postoperatively with patient-controlled analgesia (PCA), 55 patients treated with a multimodal perioperative injection have significantly less consumption of PRN morphine equivalents (0.3 mEq/kg vs. 0.5 mEq/kg; p = 0.02). Furthermore, patients treated with a perioperative injection have significantly higher rates of ambulation on postoperative day 1 compared with those treated with PCA (70.9 vs. 40.4%; p = 0.0023). CONCLUSION: Administration of a perioperative injection is effective and should be considered in the perioperative protocol in patients undergoing PSF for AIS. LEVEL OF EVIDENCE: Therapeutic Level III.

Temporal Diffusion Ratio (TDR) for imaging restricted diffusion: Optimisation and pre-clinical demonstration.

Temporal Diffusion Ratio (TDR) is a recently proposed dMRI technique (Dell'Acqua et al., proc. ISMRM 2019) which provides contrast between areas with restricted diffusion and areas either without restricted diffusion or with length scales too small for characterisation. Hence, it has a potential for informing on pore sizes, in particular the presence of large axon diameters or other cellular structures. TDR employs the signal from two dMRI acquisitions obtained with the same, large, b-value but with different diffusion gradient waveforms. TDR is advantageous as it employs standard acquisition sequences, does not make any assumptions on the underlying tissue structure and does not require any model fitting, avoiding issues related to model degeneracy. This work for the first time introduces and optimises the TDR method in simulation for a range of different tissues and scanner constraints and validates it in a pre-clinical demonstration. We consider both substrates containing cylinders and spherical structures, representing cell soma in tissue. Our results show that contrasting an acquisition with short gradient duration, short diffusion time and high gradient strength with an acquisition with long gradient duration, long diffusion time and low gradient strength, maximises the TDR contrast for a wide range of pore configurations. Additionally, in the presence of Rician noise, computing TDR from a subset (50% or fewer) of the acquired diffusion gradients rather than the entire shell as proposed originally further improves the contrast. In the last part of the work the results are demonstrated experimentally on rat spinal cord. In line with simulations, the experimental data shows that optimised TDR improves the contrast compared to non-optimised TDR. Furthermore, we find a strong correlation between TDR and histology measurements of axon diameter. In conclusion, we find that TDR has great potential and is a very promising alternative (or potentially complement) to model-based approaches for informing on pore sizes and restricted diffusion in general.

Phylogenetic inference of pneumococcal transmission from cross-sectional data, a pilot study.

Background: Inference on pneumococcal transmission has mostly relied on longitudinal studies which are costly and resource intensive. Therefore, we conducted a pilot study to test the ability to infer who infected whom from cross-sectional pneumococcal sequences using phylogenetic inference. Methods: Five suspected transmission pairs, for which there was epidemiological evidence of who infected whom, were selected from a household study. For each pair, Streptococcus pneumoniae full genomes were sequenced from nasopharyngeal swabs collected on the same day. The within-host genetic diversity of the pneumococcal population was used to infer the transmission direction and then cross-validated with the direction suggested by the epidemiological records. Results: The pneumococcal genomes clustered into the five households from which the samples were taken. The proportion of concordantly inferred transmission direction generally increased with increasing minimum genome fragment size and single nucleotide polymorphisms. We observed a larger proportion of unique polymorphic sites in the source bacterial population compared to that of the recipient in four of the five pairs, as expected in the case of a transmission bottleneck. The only pair that did not exhibit this effect was also the pair that had consistent discordant transmission direction compared to the epidemiological records suggesting potential misdirection as a result of false-negative sampling. Conclusions: This pilot provided support for further studies to test if the direction of pneumococcal transmission can be reliably inferred from cross-sectional samples if sequenced with sufficient depth and fragment length.

Combining rapid diagnostic tests to estimate primary and post-primary dengue immune status at the point of care.

BACKGROUND: Characterising dengue virus (DENV) infection history at the point of care is challenging as it relies on intensive laboratory techniques. We investigated how combining different rapid diagnostic tests (RDTs) can be used to accurately determine the primary and post-primary DENV immune status of reporting patients during diagnosis. METHODS AND FINDINGS: Serum from cross-sectional surveys of acute suspected dengue patients in Indonesia (N:200) and Vietnam (N: 1,217) were assayed using dengue laboratory assays and RDTs. Using logistic regression modelling, we determined the probability of being DENV NS1, IgM and IgG RDT positive according to corresponding laboratory viremia, IgM and IgG ELISA metrics. Laboratory test thresholds for RDT positivity/negativity were calculated using Youden's J index and were utilized to estimate the RDT outcomes in patients from the Philippines, where only data for viremia, IgM and IgG were available (N:28,326). Lastly, the probabilities of being primary or post-primary according to every outcome using all RDTs, by day of fever, were calculated. Combining NS1, IgM and IgG RDTs captured 94.6% (52/55) and 95.4% (104/109) of laboratory-confirmed primary and post-primary DENV cases, respectively, during the first 5 days of fever. Laboratory test predicted, and actual, RDT outcomes had high agreement (79.5% (159/200)). Among patients from the Philippines, different combinations of estimated RDT outcomes were indicative of post-primary and primary immune status. Overall, IgG RDT positive results were confirmatory of post-primary infections. In contrast, IgG RDT negative results were suggestive of both primary and post-primary infections on days 1-2 of fever, yet were confirmatory of primary infections on days 3-5 of fever. CONCLUSION: We demonstrate how the primary and post-primary DENV immune status of reporting patients can be estimated at the point of care by combining NS1, IgM and IgG RDTs and considering the days since symptoms onset. This framework has the potential to strengthen surveillance operations and dengue prognosis, particularly in low resource settings.

Factors that Influence Acquisition of Lower Extremity Braces in the Pediatric Orthopaedic Population.

BACKGROUND: Lower extremity brace-wear compliance has been studied in pediatrics, but failure to acquire a prescribed brace has not been included. The purpose of this study was to evaluate brace acquisition as a component of brace-wear compliance. METHODS: Records of patients (0 to 21 y) prescribed lower extremity braces from 2017 to 2019 were reviewed. Diagnoses included cerebral palsy, spina bifida, short Achilles tendon, clubfoot, and other. Brace type was categorized as clubfoot foot abduction orthosis, ankle-foot orthosis, knee, hip, or custom/other braces. Brace prescription and acquisition dates were recorded. Insurance was classified as government, private, or uninsured. Patient demographics included age, sex, race, and calculated area deprivation index. RESULTS: Of the 1176 prescribed lower extremity braces, 1094 (93%) were acquired while 82 (7%) were not. The odds ratios (OR) of failure to acquire a prescribed brace in Black and Hispanic patients were 1.64 and 2.71 times that in White patients, respectively (95% confidence interval: 1.01-2.71, P=0.045; 1.23-5.6, P=0.015); in patients without insurance, the OR was 8.48 times that in privately insured patients (95% confidence interval: 1.93-31.1, P=0.007). The ORs of failure to acquire were 2.12 (P=0.003) in patients 4 years or more versus 0 to 3 years, 4.17 (P<0.0001) in cerebral palsy versus clubfoot, and 4.12 (P=0.01) in short Achilles tendon versus clubfoot. There was no significant association between sex or area deprivation index and failure of brace acquisition. CONCLUSIONS: In our cohort, 7% of prescribed braces were not acquired. Black or Hispanic race, lack of insurance, and older age were associated with failure to acquire prescribed braces. Braces prescribed for clubfoot were acquired more often than for cerebral palsy or short Achilles tendon. Brace-wear compliance is an established factor in treatment success and recurrence. This study identified risk factors for failed brace acquisition, a critical step for improving compliance. These results may help effect changes in the current system that may lead to more compliance with brace wear. LEVEL OF EVIDENCE: Level III-retrospective cohort study.

Estimating the annual dengue force of infection from the age of reporting primary infections across urban centres in endemic countries.

BACKGROUND: Stratifying dengue risk within endemic countries is crucial for allocating limited control interventions. Current methods of monitoring dengue transmission intensity rely on potentially inaccurate incidence estimates. We investigated whether incidence or alternate metrics obtained from standard, or laboratory, surveillance operations represent accurate surrogate indicators of the burden of dengue and can be used to monitor the force of infection (FOI) across urban centres. METHODS: Among those who reported and resided in 13 cities across the Philippines, we collected epidemiological data from all dengue case reports between 2014 and 2017 (N 80,043) and additional laboratory data from a cross-section of sampled case reports (N 11,906) between 2014 and 2018. At the city level, we estimated the aggregated annual FOI from age-accumulated IgG among the non-dengue reporting population using catalytic modelling. We compared city-aggregated FOI estimates to aggregated incidence and the mean age of clinically and laboratory diagnosed dengue cases using Pearson's Correlation coefficient and generated predicted FOI estimates using regression modelling. RESULTS: We observed spatial heterogeneity in the dengue average annual FOI across sampled cities, ranging from 0.054 [0.036-0.081] to 0.249 [0.223-0.279]. Compared to FOI estimates, the mean age of primary dengue infections had the strongest association (ρ -0.848, p value<0.001) followed by the mean age of those reporting with warning signs (ρ -0.642, p value 0.018). Using regression modelling, we estimated the predicted annual dengue FOI across urban centres from the age of those reporting with primary infections and revealed prominent spatio-temporal heterogeneity in transmission intensity. CONCLUSIONS: We show the mean age of those reporting with their first dengue infection or those reporting with warning signs of dengue represent superior indicators of the dengue FOI compared to crude incidence across urban centres. Our work provides a framework for national dengue surveillance to routinely monitor transmission and target control interventions to populations most in need.

Serological Evidence of Widespread Zika Transmission across the Philippines.

Zika virus (ZIKV) exposure across flavivirus-endemic countries, including the Philippines, remains largely unknown despite sporadic case reporting and environmental suitability for transmission. Using laboratory surveillance data from 2016, 997 serum samples were randomly selected from suspected dengue (DENV) case reports across the Philippines and assayed for serological markers of short-term (IgM) and long-term (IgG) ZIKV exposure. Using mixture models, we re-evaluated ZIKV IgM/G seroprevalence thresholds and used catalytic models to quantify the force of infection (attack rate, AR) from age-accumulated ZIKV exposure. While we observed extensive ZIKV/DENV IgG cross-reactivity, not all individuals with active DENV presented with elevated ZIKV IgG, and a proportion of dengue-negative cases (DENV IgG-) were ZIKV IgG-positive (14.3%, 9/63). We identified evidence of long-term, yet not short-term, ZIKV exposure across Philippine regions (ZIKV IgG+: 31.5%, 314/997) which was geographically uncorrelated with DENV exposure. In contrast to the DENV AR (12.7% (95%CI: 9.1-17.4%)), the ZIKV AR was lower (5.7% (95%CI: 3-11%)) across the country. Our results provide evidence of widespread ZIKV exposure across the Philippines and suggest the need for studies to identify ZIKV infection risk factors over time to better prepare for potential future outbreaks.

Intraobserver and Interobserver Reliability of the Peritubercle Lucency Sign in Slipped Capital Femoral Epiphysis.

BACKGROUND: An area of enlargement of the metaphyseal socket around the epiphyseal tubercle, termed the peritubercle lucency sign, has recently been introduced as a possible predictor of contralateral slipped capital femoral epiphysis in patients with previous unilateral slipped capital femoral epiphysis. This study aimed to assess intraobserver and interobserver reliability for detecting the presence or absence of the peritubercle lucency sign. METHODS: Thirty-five radiographs were presented to 6 fellowship-trained pediatric orthopaedic surgeons on 2 separate occasions 30 days apart, ensuring that the images were shown in a different order on the second exposure. Both times the reviewers recorded whether the peritubercle lucency sign was present or absent in each of the radiographs. Statistical analysis was performed to determine the intraobserver and interobserver reliability. RESULTS: In the intraobserver analysis, percent agreement between the first and second time the radiographs were reviewed varied between 62.9% and 85.7%, for an average intraobserver agreement of 74.8%. κ values for the 6 reviewers varied between 0.34 and 0.716, with an average intraobserver κ value of 0.508. The interobserver percent agreement was 40.0% for the first time the radiographs were reviewed, 42.9% the second time, and the overall interobserver percent agreement was 29%. The interobserver κ value was 0.44 the first time the radiographs were reviewed, 0.45 the second time, and the overall interobserver κ value was 0.45. DISCUSSION: On the basis of our findings, the peritubercle lucency has modest intraobserver and interobserver reliability at best and should be used with other currently used factors, such as age, presence of endocrinopathy, status of triradiate cartilage, posterior sloping angle, and modified Oxford score, in determining the need for prophylactic pinning. Further refinement of the definition of the peritubercle lucency sign may be needed to improve agreement and reliability of the sign. LEVEL OF EVIDENCE: Level III-prognostic study.

B. burgdorferi sensu lato-induced inhibition of antigen presentation is mediated by RIP1 signaling resulting in impaired functional T cell responses towards Candida albicans.

Antigen presentation is a crucial innate immune cell function that instructs adaptive immune cells. Loss of this pathway severely impairs the development of adaptive immune responses. To investigate whether B. burgdorferi sensu lato. spirochetes modulate the induction of an effective immune response, primary human PBMCs were isolated from healthy volunteers and stimulated with B. burgdorferi s.l. Through cell entry, TNF receptor I, and RIP1 signaling cascades, B. burgdorferi s.l. strongly downregulated genes and proteins involved in antigen presentation, specifically HLA-DM, MHC class II and CD74. Antigen presentation proteins were distinctively inhibited in monocyte subsets, monocyte-derived macrophages, and dendritic cells. When compared to a range of other pathogens, B. burgdorferi s.l.-induced suppression of antigen presentation appears to be specific. Inhibition of antigen presentation interfered with T-cell recognition of B. burgdorferi s.l., and memory T-cell responses against Candidaalbicans. Re-stimulation of PBMCs with the commensal microbe C.albicans following B. burgdorferi s.l. exposure resulted in significantly reduced IFN-γ, IL-17 and IL-22 production. These findings may explain why patients with Lyme borreliosis develop delayed adaptive immune responses. Unravelling the mechanism of B. burgdorferi s.l.-induced inhibition of antigen presentation, via cell entry, TNF receptor I, and RIP1 signaling cascades, explains the difficulty to diagnose the disease based on serology and to obtain an effective vaccine against Lyme borreliosis.

Does symptom severity predict response to low-dose onabotulinumtoxinA for the treatment of urgency urinary incontinence?

OBJECTIVE: Intradetrusor onabotulinumtoxinA is a third-line treatment for urgency urinary incontinence (UUI) which is customarily reserved for severe disease. We sought to determine if symptom severity predicts the proportional response to onabotulinumtoxinA and whether low-dose injection may be an appropriate treatment for mild-moderate symptoms. STUDY DESIGN: This prospective cohort study compared patients with urgency urinary incontinence who were recruited from the Urogynecology Clinic with mild-moderate (2-9 episodes/3-day diary) and severe UUI (>9 episodes/3-day diary) symptoms. Twenty-eight subjects were treated (11 mild-moderate, 17 severe) with 50 units of intradetrusor onabotulinumtoxinA. Voiding diaries and validated questionnaires (UDI-6 and IIQ-7) were collected at baseline and one, six, and twelve months post-treatment. The primary outcome was the difference in percent reduction in UUI episodes per 3-day diary at one month. Secondary outcomes included differences in absolute reduction of UUI events, treatment success rate (defined as greater than 50% reduction in UUI episodes), changes in UDI-6 and IIQ-7 questionnaire scores, and rates of urinary retention, self-catheterization, and urinary tract infection. Normally distributed data are presented as means with standard deviations (SD) and groups were compared using the two sample t-test. Data that were not normally distributed are presented as medians with the interquartile range (IQR) and were compared using the Wilcoxon rank sum test. RESULTS: The mild-moderate group showed median improvement; 100% (IQR: 100%, 100%) and severe group; 81% (IQR: 35%, 100%), p < 0.019. Both had significant improvement in UUI episodes; the mild-moderate group decreased by four and the severe group by 15. No differences were noted in percent reduction between groups. There was no association between baseline severity and percent reduction in UUI episodes (rs = 0.127, p = 0.544); however, absolute reduction was highly correlated (rs = -0.821, p < 0.001). Treatment success was 90% in mild-moderate and 73% in the severe group (p = 0.615). Complications included urinary tract infections (25%) and intermittent catheterization (3.6%). CONCLUSIONS: Patients with both mild-moderate and severe symptoms showed a statistically significant improvement in UUI events from baseline to one month, but no difference between the groups in proportional improvement or treatment success.

Immune responses to malaria pre-erythrocytic stages: Implications for vaccine development.

Radiation-attenuated sporozoites induce sterilizing immunity and remain the 'gold standard' for malaria vaccine development. Despite practical challenges in translating these whole sporozoite vaccines to large-scale intervention programmes, they have provided an excellent platform to dissect the immune responses to malaria pre-erythrocytic (PE) stages, comprising both sporozoites and exoerythrocytic forms. Investigations in rodent models have provided insights that led to the clinical translation of various vaccine candidates-including RTS,S/AS01, the most advanced candidate currently in a trial implementation programme in three African countries. With advances in immunology, transcriptomics and proteomics, and application of lessons from past failures, an effective, long-lasting and wide-scale malaria PE vaccine remains feasible. This review underscores the progress in PE vaccine development, focusing on our understanding of host-parasite immunological crosstalk in the tissue environments of the skin and the liver. We highlight possible gaps in the current knowledge of PE immunity that can impact future malaria vaccine development efforts.

A serological framework to investigate acute primary and post-primary dengue cases reporting across the Philippines.

BACKGROUND: In dengue-endemic countries, targeting limited control interventions to populations at risk of severe disease could enable increased efficiency. Individuals who have had their first (primary) dengue infection are at risk of developing more severe secondary disease, thus could be targeted for disease prevention. Currently, there is no reliable algorithm for determining primary and post-primary (infection with more than one flavivirus) status from a single serum sample. In this study, we developed and validated an immune status algorithm using single acute serum samples from reporting patients and investigated dengue immuno-epidemiological patterns across the Philippines. METHODS: During 2015/2016, a cross-sectional sample of 10,137 dengue case reports provided serum for molecular (anti-DENV PCR) and serological (anti-DENV IgM/G capture ELISA) assay. Using mixture modelling, we re-assessed IgM/G seroprevalence and estimated functional, disease day-specific, IgG:IgM ratios that categorised the reporting population as negative, historical, primary and post-primary for dengue. We validated our algorithm against WHO gold standard criteria and investigated cross-reactivity with Zika by assaying a random subset for anti-ZIKV IgM and IgG. Lastly, using our algorithm, we explored immuno-epidemiological patterns of dengue across the Philippines. RESULTS: Our modelled IgM and IgG seroprevalence thresholds were lower than kit-provided thresholds. Individuals anti-DENV PCR+ or IgM+ were classified as active dengue infections (83.1%, 6998/8425). IgG- and IgG+ active dengue infections on disease days 1 and 2 were categorised as primary and post-primary, respectively, while those on disease days 3 to 5 with IgG:IgM ratios below and above 0.45 were classified as primary and post-primary, respectively. A significant proportion of post-primary dengue infections had elevated anti-ZIKV IgG inferring previous Zika exposure. Our algorithm achieved 90.5% serological agreement with WHO standard practice. Post-primary dengue infections were more likely to be older and present with severe symptoms. Finally, we identified a spatio-temporal cluster of primary dengue case reporting in northern Luzon during 2016. CONCLUSIONS: Our dengue immune status algorithm can equip surveillance operations with the means to target dengue control efforts. The algorithm accurately identified primary dengue infections who are at risk of future severe disease.

Evaluation of Outcomes Before and After Implementation of a Standardized Postoperative Care Pathway in Pediatric Posterior Spinal Fusion Patients.

BACKGROUND: Standardized pathways decrease variability and improve outcomes and safety. PURPOSE: The article aims to evaluate outcomes of a standardized postoperative care pathway compared with individual surgeon preference. METHODS: A review of patients prestandardization and poststandardization was performed. Patients between the ages of 10-21 years with adolescent idiopathic scoliosis (ICD-9 code 737.30) admitted to the hospital for posterior spinal fusion (CPT code 22630) were included in the study. The prestandardization group (25 patients) was enrolled from April 1, 2010, through March 30, 2011, and the poststandardization group (25 patients) from April 1, 2014, to March 30, 2015. Exclusion criteria were renal disease, epilepsy, neurological disorder, or postoperative complications that led to change in routine care including ileus or fever greater than 102 °F. Data were analyzed using the Wilcoxon signed rank test, with significance set at p < .001. RESULTS: The length of stay (p = .0166), time to ambulation (p < .0001), patient-controlled analgesia use (p < .0001), and postoperative time to resumption of regular diet (p < .0001) were all significantly decreased in the poststandardization group. There were no complications or readmissions in either group. CONCLUSION: The standardized pathway resulted in shorter length of stay, decreased narcotic use, decreased time to regular diet, and decreased time to ambulation with no increase in complication rates.

Flexible intramedullary nailing of femoral shaft fractures: closed versus open reduction.

Children's femoral shaft fractures are commonly treated with flexible intramedullary nailing after closed or open reduction, but there is little information concerning indications for open reduction. The purpose of this study was to determine radiographic and clinical features likely to lead to open reduction before flexible intramedullary nailing. Record review identified 158 femoral shaft fractures treated with flexible intramedullary nailing. In addition to patient demographics and mechanism of injury, data obtained included surgeon name, estimated blood loss, type of reduction, type and diameter of nail, type of operating table, the use of percutaneous reduction techniques or supplemental casting, time to and duration of surgery, total time in operating room, and time to union. Fracture ratios were calculated based on established radiographic protocol. Of 158 fractures, 141 were treated with closed reduction and 17 with open reduction. The anteroposterior fracture index (1.3 ± 0.4, P = 0.0007), surgeon (P = 0.002), and flattop operating table (0.05) were associated with open reduction. Smaller lateral diameter of bone at the fracture site, transverse fracture, and surgeon were all found to be independent risk factors for open reduction; patient characteristics, including age, sex, and BMI, did not seem to influence the choice of open reduction. Fractures with a lower fracture index or pattern resembling a transverse fracture rather than oblique or spiral had an increased risk of converting to an open reduction. Surgeon preference and use of flattop tables also had a significant influence on how the fracture was treated.

Pediatric Patients with Spondylolysis Have High Rates of Vitamin-D Deficiency.

The objective of this study was to document the 25-hydroxyvitamin D status of patients with a confirmed diagnosis of spondylolysis to determine if these patients have increased rates of vitamin D deficiency. After confirming the diagnosis of spondylolysis, patients were prospectively enrolled in this study. A total of 39 patients (30 male, 9 female) with a mean age of 14.9 years and a mean BMI of 22.9 had vitamin D levels drawn after imaging confirmed the diagnosis of spondylolysis. The mean 25-hydroxyvitamin D level was 26 ng/ml. Only 9 patients (23.1%) were considered to have normal vitamin D levels > 32 ng/ml. An additional 22 patients (56.4%) had insufficient values of 20 to 32 ng/ml, and 8 patients (20.5%) had vitamin D deficiency with values <20 ng/ml. Pediatric patients presenting with spondylolysis, regardless of race or age, have high rates of 25-hydroxyvitamin D deficiency. (Journal of Surgical Orthopaedic Advances 28(4):257-259, 2019).

Operating Room Personnel Determine Efficiency of Pediatric Spinal Fusions for Scoliosis.

STUDY DESIGN: Retrospective chart review. OBJECTIVES: To investigate the effect of different surgeons, anesthesiologists, and cRNAs individually and in teams on various perioperative and operative time intervals in a large, high-volume children's hospital. SUMMARY OF BACKGROUND DATA: Along with individual factors, studies have indicated that team factors play a role in efficiency, with larger teams leading to increased procedure times. An operating room (OR) staff dedicated to orthopedics has been reported to decrease turnover time; however, the characteristics and behaviors of surgical team members, to our knowledge, have not been analyzed as possible factors contributing to pediatric OR efficiency, and limited research has been conducted in the field of orthopedic personnel. METHODS: Chart review identified consecutive pediatric and adolescent patients who had primary posterior spinal fusion (PSF) of ≥7 levels for correction of spinal deformity. Time intervals and delays were recorded based on previous studies looking at OR efficiency and adjusted to the specific time points available in our perioperative nursing records. RESULTS: Adjusted for etiology, osteotomy, fusion levels, distance from hospital, staff switch, and body mass index, there was a significant difference in patient wait time among anesthesiologists, surgeon-anesthesiologist, and anesthesiologist-certified registered nurse anesthetist (cRNA) teams; in surgery prep time and total prep among surgeons and SA teams; and in surgery time and total room time among surgeons. There were no significant differences among cRNAs, individually, in any time interval. CONCLUSIONS: Anesthesiologists have a significant effect before and surgeons have a significant effect after entry into the OR. Identification of this variability provides an opportunity to study the differences in habits and processes of high- and low-efficiency teams, which can then be applied to all teams with the goal of improving performance of all surgical teams. LEVEL OF EVIDENCE: Level IV, case series.

The Role of Computed Tomography and Magnetic Resonance Imaging in the Diagnosis of Pediatric Thoracolumbar Compression Fractures.

BACKGROUND: Because of concerns about radiation exposure, some centers consider magnetic resonance imaging (MRIs) the preferred imaging modality for pediatric thoracic and/or lumbar compression fractures. The purpose of this study was to evaluate the sensitivity of computed tomography (CT) and MRI in diagnosing thoracolumbar compression fractures and the utility of MRI in their management. METHODS: Retrospective review identified 52 patients aged 0 to 18 years with 191 thoracic and/or lumbar compression fractures who had both CT and MRI during the initial trauma evaluation. The decision to perform CT and/or MRI was made by the attending pediatric spine surgeon. In all cases the CT scan was performed before the MRI. All imaging studies were reviewed by a board-certified pediatric radiologist and attending pediatric spine surgeon. RESULTS: Only 10 patients (19%) had a single-level injury. Of 42 with multiple compression fractures, 34 (81%) had fractures in contiguous levels, and 8 had noncontiguous injuries. Comparing CT and MRI, there was complete agreement in the number and distribution of fractures in 23 patients (44%). MRI identified additional levels of fracture in 15 patients (29%); 14 (27%) had fewer levels fractured on MRI than CT. Only one patient (2%) had fractures seen on MRI after a normal CT scan. Complete correlation between CT and MRI was seen in 59% (17/29) of patients aged 11 to 18 years, compared with 26% (6/23) of patients younger than 11. CONCLUSIONS: In pediatric patients with mild thoracic or lumbar compression fracture(s), CT scan demonstrates a high sensitivity in determining the presence or absence of a fracture compared with MRI. Although some variability exists between the 2 modalities in the exact number of spinal levels involved, the definitive treatment and outcome were not changed by the addition of MRI. The information that may be obtained from an MRI must be weighed against the increased time and expense of the study, as well as the risks associated with sedation when necessary. LEVEL OF EVIDENCE: Level II-diagnostic study.

Biomechanical analysis of spino-pelvic postural configurations in spondylolysis subjected to various sport-related dynamic loading conditions.

PURPOSE: To study the risks of spondylolysis due to extrinsic loading conditions related to sports activities and intrinsic spino-pelvic postural parameters [pelvic incidence (PI) and sacral slope (SS)]. METHODS: A comprehensive osseo-disco-ligamentous L4-S1 finite element model was built for three cases with spondylolysis representing three different spino-pelvic angular configurations (SS = 32°, 47°, 59° and PI = 49°, 58°, 72°, respectively). After simulating the standing posture, 16 dynamic loading conditions were computationally tested for each configuration by combining four sport-related loads (compression, sagittal and lateral bending and axial torque). For each simulation, the Von Mises stress, L5-S1 facet contact force and resultant internal loads at the sacral endplate were computed. Significant effects were determined with an ANOVA. RESULTS: The maximal stress and volume of cancellous bone in the pars with stress higher than 75% of the ultimate stress were higher with 900 N simulated compression (2.2 MPa and 145 mm3) compared to only the body weight (1.36 MPa and 20.9 mm3) (p < 0.001). Combined compression with 10 Nm of flexion and an axial torque of 6 Nm generated the highest stress conditions (up to 2.7 MPa), and L5-S1 facet contact force (up to 430 N). The maximal stress was on average 17% higher for the case with the highest SS compared to the one with lowest SS for the 16 tested conditions (p = 0.0028). CONCLUSIONS: Combined flexion and axial rotation with compression generated the highest stress conditions related to risks of spondylolysis. The stress conditions intensify in patients with higher PI and SS. These slides can be retrieved under Electronic Supplementary Material.