The Role of Obesity in Pediatric Orthopedics.

Pediatric obesity has become a worldwide epidemic and leads to notable effects on the developing skeleton that can have lifelong implications. Obesity in the pediatric population alters bone metabolism, increasing the risk for fracture. It can alter the presentation of common pediatric orthopaedic conditions such as scoliosis. Obesity also leads to changes in the patterns and severity of pediatric fractures as well as alters conservative fracture treatment due to increased displacement risk. Obese pediatric trauma patients place a high burden on the nationwide hospital system in a variety of ways including the increased risk of perioperative complications. Obesity is modifiable, and addressing the issue can improve the orthopaedic and overall health of children.

Measurement of Intraoperative Blood Loss in Pediatric Orthopaedic Patients: Evaluation of a New Method.

INTRODUCTION: Our goal was to validate a new method of intraoperative blood loss measurement in pediatric patients who undergo orthopaedic surgery. METHODS: We prospectively collected surgical sponges from 55 patients who underwent pediatric posterior spinal fusion, single-event multilevel surgery, or hip reconstruction for measurement of intraoperative blood loss. We enrolled patients if expected estimated blood loss (EBL) was >200 mL. The methods used for blood loss assessment included the Triton sponge scanning system, visual method, gravimetric method, and measured assay (reference) method. RESULTS: The Triton system calculation of cumulative EBL per patient against the reference method yielded a strong positive linear correlation (R2 = 0.88). A weaker correlation was noted between the gravimetric method and reference EBL (R2 = 0.49). The Triton system had a low bias and narrow limits of agreement relative to the reference method (49 mL; 95% CI, 30 to 68). The gravimetric method had a higher bias and wider limits of agreement (101 mL; 95% CI, 67 to 135). The comparison of visual total EBL against the reference method yielded a notable discrepancy. DISCUSSION: Estimated blood loss measured using the Triton system correlated better with the reference method than with the gravimetric method. The visual estimation method was found to be inaccurate. Intraoperative use of the Triton system is convenient and precise for monitoring intraoperative blood loss.

High-performance, robustly verified Monte Carlo simulation with FullMonte.

We introduce the FullMonte tetrahedral 3-D Monte Carlo (MC) software package for simulation, visualization, and analysis of light propagation in heterogeneous turbid media including tissue. It provides the highest computational performance and richest set of input, output, and analysis facilities of any open-source tetrahedral-mesh MC light simulator. It also provides a robust framework for statistical verification. A scripting interface makes set-up of simulation runs simple, including parameter sweeps, while simultaneously providing customization options. Data formats shared with class-leading visualization tools, VTK and Paraview, facilitate interactive generation of publication-quality fluence and irradiance maps. The simulator can read and write file formats supported by other similar simulators, such as TIM-OS, MMC, COMSOL (finite-element simulations), and MCML to support comparison. Where simulator features permit, FullMonte can take a single test case, run it in multiple software packages, and load the results together for comparison. Example meshes, optical properties, set-up scripts, and output files are provided for user convenience. We demonstrate its use in several test cases, including photodynamic therapy of the brain, bioluminescence imaging (BLI) in a mouse phantom, and a comparison against MCML for layered geometries. Application domains that can benefit from use of FullMonte include photodynamic, photothermal, and photobiomodulation therapies, BLI, diffuse optical tomography, MC software development, and biophotonics education. Since MC results may be used for preclinical or even clinical experiments, a robust and rigorous verification process is essential. Being a stochastic numerical method, MC simulation has unique challenges associated with verification of output results since observed differences may be due simply to output variance or actual differences in expected output. We describe and have implemented a rigorous and statistically justified framework for comparing between simulators of the same class and for performing regression testing.

Automatic interstitial photodynamic therapy planning via convex optimization.

Finding a high-quality treatment plan is an essential, yet difficult, stage of Photodynamic therapy (PDT) as it will determine the therapeutic efficacy in eradicating malignant tumors. A high-quality plan is patient-specific, and provides clinicians with the number of fiber-based spherical diffusers, their powers, and their interstitial locations to deliver the required light dose to destroy the tumor while minimizing the damage to surrounding healthy tissues. In this work, we propose a general convex light source power allocation algorithm that, given light source locations, guarantees optimality of the resulting solution in minimizing the over/under-dosage of volumes of interest. Furthermore, we provide an efficient framework for source selection with concomitant power reallocation to achieve treatment plans with a clinically feasible number of sources and comparable quality. We demonstrate our algorithms on virtual test cases that model glioblastoma multiforme tumors, and evaluate the performance of four different photosensitizers with different activation wavelengths and specific tissue uptake ratios. Results show an average reduction of the damage to organs-at-risk (OAR) by 29% to 31% with comparable runtime to existing power allocation techniques.

Three-dimensional computed tomography for determination of femoral anteversion in a cerebral palsy model.

BACKGROUND: Previous investigation has proven 3-dimensional (3D) computed tomography (CT) to be a poor method of assessing femoral anteversion in patients with cerebral palsy. However, new advancements in CT software yield the potential to improve upon those dated results. METHODS: CT was performed on 9 femoral models with varying amounts of anteversion (20 to 60 degrees) and varying neck-shaft angles (120 to 160 degrees). Each model was scanned in 2 holding devices. One holder placed the femur in an ideal position relative to the gantry. The other placed the femur in flexion, adduction, and internal rotation simulating a common lower extremity posture in cerebral palsy. Femoral anteversion was measured on 3D reconstructions by 4 observers on 2 separate occasions. Interobserver and intraobserver reliability, accuracy, and the effect of increasing neck-shaft angle of the measurements were examined and compared with previously published data using the same models. RESULTS: Pearson correlation coefficients between first and second measurements by the same examiner were all above 0.96 regardless of positioning of the femur in the gantry. The correlation coefficients among all examiners were 0.97 regardless of positioning of the femur in the gantry. Accuracy in measurements was comparable using 3D CT techniques with mean differences between the normal and cerebral palsy-positioned models of <3.6 degrees (SD, 3.1 to 3.3 degrees). Accuracy of the study's 3D CT technique in measuring femoral anteversion in cerebral palsy-positioned femurs was significantly more accurate than that of 2D CT (P<0.0001). CONCLUSIONS: Recent improvements in processing software and 3D reconstruction have made assessment of femoral anteversion with 3D CT accurate through the studied range of anteversion and neck-shaft angles. Using this technique, high intraobserver and interobserver reliability in the determination of femoral anteversion can be expected regardless of neck-shaft angle or postural deformity. LEVEL OF EVIDENCE: Level II.

The Efficacy of Amicar Versus Tranexamic Acid in Pediatric Spinal Deformity Surgery: A Prospective, Randomized, Double-Blinded Pilot Study.

STUDY DESIGN: Single-center, prospective, randomized, double-blinded trial. OBJECTIVES: To compare blood loss, allogenic transfusion requirements, and coagulation parameters between pediatric spinal deformity patients receiving aminocaproic acid (Amicar) or tranexamic acid (TXA) during posterior spinal fusion. SUMMARY OF BACKGROUND DATA: Amicar and TXA have been shown to decrease blood loss in pediatric spinal deformity cases compared with controls. The difference in efficacy between these medications in this population has not been reported. METHODS: Enrolled patients were randomized to receive either Amicar or TXA during scoliosis surgery. Baseline demographic and deformity comparisons were collected. Intraoperative comparisons included estimated and calculated blood loss, number of levels instrumented, number of osteotomies, operative time, and allogenic transfusion requirements. Preoperative and postoperative hemoglobin, platelets, prothrombin time, partial prothrombin time (PTT), international normalized ratio (INR), and fibrinogen were recorded. RESULTS: A total of 47 patients were enrolled with data available for review (N = 25, Amicar; N = 22, TXA). No difference in cohorts was found in demographics, preoperative hemoglobin, platelets, prothrombin time, PTT, INR, initial Cobb angle, average number of: levels fused, patients with osteotomies and osteotomies, operative time, and final Cobb angles. Estimated blood loss was significantly less (about 221 mL) than the calculated blood loss in both groups (p = .003). Estimated blood loss (1,088 vs. 726 mL; p = .055) and calculated blood loss (1,366 vs. 903 mL; p = .13) trended higher in the Amicar group. Although no difference in allogenic transfusion rates (20% vs. 14%) was observed, average volumes transfused were significantly higher in the Amicar cohort (1,014 vs. 461 mL; p = .03). The TXA cohort demonstrated a statistically significant smaller change in INR, a lower PTT, and greater fibrinogen levels postoperatively. CONCLUSIONS: Compared with Amicar, TXA use was associated with a lower allogenic transfusion requirement, less alteration in postoperative clotting studies, and a trend toward lower blood loss in pediatric posterior spinal fusion patients.

Cervical spinal cord injury after thoracic spinal instrumentation: a case series.

STUDY DESIGN: Retrospective case report of 2 cases. OBJECTIVE: To describe 2 cases of cervical spinal cord injury/vascular insult after posterior instrumentation of thoracic/thoracolumbar scoliosis. SUMMARY OF BACKGROUND DATA: Spinal cord injury is an uncommon but well-documented complication associated with spinal deformity surgery. The midthoracic spinal cord is most vulnerable to these presumed vascular insults. Injuries above the level of instrumentation are rare. METHODS: In this report, we review the clinical histories of 2 adolescent females undergoing posterior spinal fusion with subsequent cervical spinal cord injuries. RESULTS: In both cases, intraoperative cervical alignment appeared neutral and all hardware appeared appropriately positioned. Spinal cord monitoring demonstrated changes in 1 patient but not in the other. With time, both patients improved clinically. CONCLUSION: Cervical spinal cord injuries may occur after distal deformity correction.

Do multilevel Ponte osteotomies in thoracic idiopathic scoliosis surgery improve curve correction and restore thoracic kyphosis?

BACKGROUND: To compare the routine use of posterior-based (Ponte) osteotomies to complete inferior facetectomies in thoracic idiopathic scoliosis. Hypokyphosis is common in thoracic adolescent idiopathic scoliosis. The use of pedicle screw fixation in deformity correction can exacerbate this hypokyphosis. We hypothesized that by utilizing posterior-based Ponte osteotomies rather than facetectomies, we could improve coronal plane correction and decrease the loss of kyphosis during curve correction. METHODS: The radiographs and clinical charts of patients with idiopathic scoliosis (Lenke types I, II) who underwent isolated thoracic posterior spinal fusion utilizing primarily pedicle screw constructs from January 2008 to August 2010 were reviewed. Maximum preoperative Cobb angle, thoracic kyphosis (T5-T12), levels instrumented, number of posterior-based osteotomies, operative time, estimated blood loss, and postoperative residual coronal Cobb angle and kyphosis were recorded. Operative time per level, blood loss per level, percent main curve correction, and change in thoracic kyphosis was calculated. Patients having undergone complete inferior facetectomies and those with multilevel Ponte osteotomies were then compared. RESULTS: Eighteen patients underwent posterior spinal fusion with osteotomies and 19 patients had complete inferior facetectomies during this time period. The osteotomy cohort had a larger preoperative Cobb angle [59±10 vs. 52±8 (mean±SD); P=0.03]. No difference was observed in the preoperative kyphosis (22±15 vs. 25±12) or in levels fused (9±1 vs. 8±1). Patients with routine osteotomies had them performed at 76% of the levels instrumented. No significant difference was found in terms of percentage of coronal plane correction (84% in both groups), average postoperative kyphosis 28±8 versus 25±7, or the change in kyphosis 6±14 versus 0±2 degrees, in the osteotomy and the facetectomy groups, respectively. Estimated blood loss per level was significantly higher in the osteotomy group (97±42 mL vs. 66±25 mL; P=0.01) as was time per level 31±5 versus 23±3 minutes/level (P<0.001). CONCLUSIONS: This study shows a significantly higher blood loss and operative time associated with the use of routine posterior osteotomies in the thoracic spine without a significant improvement in coronal or sagittal correction.

Comparing results of posterior spine fusion in patients with AIS: Are two surgeons better than one?

AIMS: Spinal deformity surgery is one of the most complicated procedures performed in pediatric orthopedics. These surgeries can account for long operative times and blood losses. Finding ways to limit patient morbidity undergoing these procedures may benefit many. We hypothesized that utilizing two fellowship trained pediatric spinal deformity surgeons would lead to decreased operative time and blood loss when compared with single surgeon. We felt very little difference would be found in terms of curve correction. METHODS: A retrospective review of spinal deformity surgeries performed at two institutions was performed. At one institution, the standard of care was to have two fellowship deformity trained surgeons perform all deformity surgeries simultaneously, while at the second institution posterior spinal fusions performed by individual surgeons were performed. The single surgeon cohort was further divided based on instrumentation type (pedicle screw vs hybrid constructs). Cases for this review were limited to posterior spinal fusions without osteotomies in patients with idiopathic or idiopathic like curves. Cohorts were compared pre-operatively for age at surgery, sex, BMI, largest Cobb angle. Intra-operative comparisons included total EBL, instrumentation type screws vs hybrid, levels fused, and operative time. Comparisons between largest remaining Cobb, EBL/level, time/level, lowest recorded Hb, allogenic transfusion requirements, length of PICU stay, and total length of hospital stay were then made. Pair-wise student t-tests was performed between cohorts with significance defined as a p-value of 0.05 or less. CONCLUSIONS: Twenty-four patients were found in the (BMP) cohort, where as eighty-two were found in the control group. No significant difference in age, sex, starting hemoglobin, BMI*, or maximum pre-operative Cobb between cohorts was found. A significantly lower number of levels were fused in the BMP cohort than the control (9 ± 2 vs 11 ± 2) p < 0.001, and likewise a significantly shorter operative time (average >2 h) was seen in the BMP cohort. Interestingly, no difference in estimated blood loss, blood loss/level fused, operative time/level fused was observed, yet a significantly greater drop in hemoglobin (average 1 g) p = 0.001 and allogenic transfusion rate was seen in the control group (4% (1/24) vs 29% (24/82)) p = 0.01. A greater improvement in Cobb angle was seen in the BMP group 46 ± 8 vs 35 ± 10° p < 0.001. No differences were seen in nights in the PICU and peri-operative complications, however patients in the BMP averaged nearly 1day less in the hospital than in the control group. Utilizing a blood management program including two surgeons in spinal deformity surgery appears to decrease operative time, blood loss, and improve curve correction. Confounding factors such as differences in number of fusion levels, curve types, instrumentation type, and institutional practices prevents drawing definitive conclusions. This is the first study to show potential benefits of utilizing a blood management program with dual surgeons in spinal deformity cases.

Blood management in pediatric spinal deformity surgery: review of a 2-year experience.

BACKGROUND: Pediatric scoliosis surgery is associated with considerable blood loss and allogenic transfusions. Transfusions contribute to morbidities and cost. A perioperative pediatric blood management program was implemented at our institution. Patients received preoperative evaluation, cell salvage, topical hemostasis, antifibrinolytics, and hypotensive anesthesia. STUDY DESIGN AND METHODS: The study was a 2-year retrospective cohort review of the program's population from September 2007 through August 2009. RESULTS: A total of 110 scoliosis surgeries were performed with only 34 and 12% of the patients requiring preoperative oral iron and erythropoietin, respectively. Neuromuscular scoliosis patients had more repaired segments and a larger transfusion rate than idiopathic scoliosis patients (36% vs. 1.7%, p = 0.001). Transfused patients had more blood loss relative to their blood volume (p = 0.001) and blood loss was associated with higher Cobb angles (p = 0.04). Logistic regression revealed that blood loss (p = 0.001), number of segments fused (p = 0.004), and lower patient weight (p = 0.007) are associated with increased odds for transfusion. Twelve patients (10.9%) were identified with low von Willebrand activity with a trend toward higher blood losses (p = 0.07) with lower activity levels. CONCLUSION: Transfusion requirements in scoliosis patients are dependent on blood loss as determined by Cobb angles and number of segments fused relative to the patients' blood volume as determined by weight. Implementation of a blood management protocol resulted in a low transfusion rate and unexpectedly led to the preoperative diagnosis of a number of patients with low levels of von Willebrand activity.

Arthroscopic excision of a painful bipartite patella fragment.

Bipartite patella is an uncommon finding, with the majority of cases discovered incidentally on radiographs. Occasionally, bipartite patella can become painful through sports activities, overuse, or following an injury, and the large majority of these cases resolve with nonoperative treatment. However, for patients who do not respond to a prolonged course of nonoperative treatment, surgical options may be considered. We report a successful case of arthroscopic excision of a painful bipartite patella fragment in a 19-year-old male collegiate basketball player. A review of the literature is included.

Acetabular retroversion in military recruits with femoral neck stress fractures.

UNLABELLED: Acetabular retroversion (AR) alters load distribution across the hip and is more prevalent in pathologic conditions involving the hip. We hypothesized the abnormal orientation and mechanical changes may predispose certain individuals to stress injuries of the femoral neck. We retrospectively reviewed the anteroposterior (AP) pelvic radiographs of 54 patients (108 hips) treated for a femoral neck stress fracture (FNSF) and compared these radiographs with those for a control group of patients with normal pelvic radiographs. We determined presence of a crossover sign (COS), femoral neck abnormalities, and neck shaft angle. The prevalence of a positive COS was greater in patients with stress fractures than in the control subjects (31 of 54 [57%] versus 17 of 54 [31%], respectively) and higher than for control subjects reported in the literature. Thirteen patients had radiographic changes of the femoral neck consistent with femoroacetabular impingement (FAI). These radiographic abnormalities were seen more commonly in retroverted hips. A greater incidence of AR was noted in patients with FNSF. Potential implications include more aggressive screening of military recruits with AR and the new onset of hip pain. Finally, we present an algorithm we use to diagnose and treat these relatively rare FNSFs. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Risser sign inter-rater and intra-rater agreement: is the Risser sign reliable?

BACKGROUND: Studies directly evaluating the reliability of the Risser sign are few in number, possess small sample sizes, and offer conflicting results. This study establishes the reliability of the Risser sign on a large sample size in an effort to provide clarification on the subject. METHODS: Two years' worth of AP pelvis radiographs from patients age 8-20 were downloaded from our institution's digital imaging system. One hundred of these images were selected for inclusion by an independent reviewer whose goal was to capture a spread of radiographs that included all Risser stages. Risser grading occurred in two rounds. In each round, three examiners randomly reviewed the 100 radiographs on three different occasions. The full AP pelvis radiograph was graded in Round 1 while only the iliac apophysis was visible in Round 2. Kappa coefficients and their confidence bounds are reported to indicate intra- and inter-observer reliability. The contrast between the rates of agreement about Risser stages in Rounds 1 versus 2 was assessed by McNemar's test. The signed-rank test was used to evaluate differences in intra-observer values between rounds. RESULTS: Round 1 inter-observer kappa was 0.76. Round 2 inter-observer kappa was 0.51. In Round 1, 63 radiographs showed perfect agreement within the same Risser stage for all observations compared to 44 radiographs with perfect agreement within the same Risser stage in Round 2 (p = 0.004). Round 1 intra-observer kappa values were 0.92, 0.86, and 0.88. Round 2 intra-observer kappa values were 0.91, 0.77, and 0.88. Intra-observer value differences between rounds were not significant for two observers (p = 0.074, 0.061) but was significant for the third observer (p = 0.002). CONCLUSION: The reliability of the Risser sign is acceptable and can be further improved when other markers of skeletal maturity on the pelvis radiograph are used to assist in grading.

Chondromyxoid fibroma of the lumbar spine in a pediatric patient.

Chondromyxoid fibroma is a rare nonmalignancy that comprises <1% of all bone tumors. It typically presents with pain, swelling, and tenderness to palpation. The lesion has a predilection for the metaphysis of long bones of the lower extremity, most commonly in the proximal tibial metaphysis. Patients often present in their second or third decade of life, although some reports have included a younger average age. Sporadic reports of chondromyxoid fibroma in the spine are found in the literature. This article presents the second case of a chondromyxoid fibroma of the lumbar spine in a pediatric patient, along with a literature review with emphasis on recurrence rates and malignant transformation.