Mark Driscoll

Biomarkers for sepsis

Bloodstream infections are a major concern because of high levels of antibiotic consumption and of the increasing prevalence of antimicrobial resistance. Bacteraemia is identified in a small percentage of patients with signs and symptoms of sepsis. Biomarkers are widely used in clinical practice and they are useful for monitoring the infectious process. Procalcitonin (PCT) and C-reactive protein (CRP) have been most widely used, but even these have limited abilities to distinguish sepsis from other inflammatory conditions or to predict outcome. PCT has been used to guide empirical antibacterial therapy in patients with respiratory infections and help to determine if antibacterial therapy can be stopped. New biomarkers such as those in this review will discuss the major types of biomarkers of bloodstream infections/sepsis, including soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), soluble urokinase-type plasminogen receptor (suPAR), proadrenomedullin (ProADM), and presepsin.

The role of spinal concave–convex biases in the progression of idiopathic scoliosis

Inadequate understanding of risk factors involved in the progression of idiopathic scoliosis restrains initial treatment to observation until the deformity shows signs of significant aggravation. The purpose of this analysis is to explore whether the concave–convex biases associated with scoliosis (local degeneration of the intervertebral discs, nucleus migration, and local increase in trabecular bone-mineral density of vertebral bodies) may be identified as progressive risk factors. Finite element models of a 26° right thoracic scoliotic spine were constructed based on experimental and clinical observations that included growth dynamics governed by mechanical stimulus. Stress distribution over the vertebral growth plates, progression of Cobb angles, and vertebral wedging were explored in models with and without the biases of concave–convex properties. The inclusion of the bias of concave–convex properties within the model both augmented the asymmetrical loading of the vertebral growth plates by up to 37% and further amplified the progression of Cobb angles and vertebral wedging by as much as 5.9° and 0.8°, respectively. Concave–convex biases are factors that influence the progression of scoliotic curves. Quantifying these parameters in a patient with scoliosis may further provide a better clinical assessment of the risk of progression.

Biomechanical analysis and modeling of different vertebral growth patterns in adolescent idiopathic scoliosis and healthy subjects

BackgroundThe etiology of AIS remains unclear, thus various hypotheses concerning its pathomechanism have been proposed. To date, biomechanical modeling has not been used to thoroughly study the influence of the abnormal growth profile (i.e., the growth rate of the vertebral body during the growth period) on the pathomechanism of curve progression in AIS. This study investigated the hypothesis that AIS progression is associated with the abnormal growth profiles of the anterior column of the spine.MethodsA finite element model of the spinal column including growth dynamics was utilized. The initial geometric models were constructed from the bi-planar radiographs of a normal subject. Based on this model, five other geometric models were generated to emulate different coronal and sagittal curves. The detailed modeling integrated vertebral body growth plates and growth modulation spinal biomechanics. Ten years of spinal growth was simulated using AIS and normal growth profiles. Sequential measures of spinal alignments were compared.Results(1) Given the initial lateral deformity, the AIS growth profile induced a significant Cobb angle increase, which was roughly between three to five times larger compared to measures utilizing a normal growth profile. (2) Lateral deformities were absent in the models containing no initial coronal curvature. (3) The presence of a smaller kyphosis did not produce an increase lateral deformity on its own. (4) Significant reduction of the kyphosis was found in simulation results of AIS but not when using the growth profile of normal subjects.ConclusionResults from this analysis suggest that accelerated growth profiles may encourage supplementary scoliotic progression and, thus, may pose as a progressive risk factor.

The presence of physiological stress shielding in the degenerative cycle of musculoskeletal disorders

The health of physiological tissue is governed by the continuous conversion of mechanical stimulus (stress) to bio-chemical response, a concept known as mechanical homeostasis. If this regulatory imperative becomes flawed, it may be detrimental, and consequently invoke or encourage the progression of various musculoskeletal disorders. This notion is corroborated by the quantification of altered function and irregular mechanical properties found within the articulations of such phenotypes as cerebral palsy. Although the divergence from healthy to irregular tissue behavior is likely multifactorial, the presence of imbalanced mechanical properties may promote the concept of physiological stress shielding. Extrapolating upon the stress shielding phenomenon may allow inferences to be drawn with respect to the pathomechanisms of progressive disorders. Further, recognition of this association may also provide a new platform from which to interpret the impact of conventional treatments aimed at such syndromes and, in turn, perhaps support new therapeutic avenues.

Development of a Detailed Volumetric Finite Element Model of the Spine to Simulate Surgical Correction of Spinal Deformities

A large spectrum of medical devices exists; it aims to correct deformities associated with spinal disorders. The development of a detailed volumetric finite element model of the osteoligamentous spine would serve as a valuable tool to assess, compare, and optimize spinal devices. Thus the purpose of the study was to develop and initiate validation of a detailed osteoligamentous finite element model of the spine with simulated correction from spinal instrumentation. A finite element of the spine from T1 to L5 was developed using properties and geometry from the published literature and patient data. Spinal instrumentation, consisting of segmental translation of a scoliotic spine, was emulated. Postoperative patient and relevant published data of intervertebral disc stress, screw/vertebra pullout forces, and spinal profiles was used to evaluate the models validity. Intervertebral disc and vertebral reaction stresses respected published in vivo, ex vivo, and in silico values. Screw/vertebra reaction forces agreed with accepted pullout threshold values. Cobb angle measurements of spinal deformity following simulated surgical instrumentation corroborated with patient data. This computational biomechanical analysis validated a detailed volumetric spine model. Future studies seek to exploit the model to explore the performance of corrective spinal devices.

Evaluation of an apparatus to be combined with a smartphone for the early detection of spinal deformities

BackgroundMobile smartphones are equipped with inclinometers enabling them to acquire angular clinical measures. The Scolioscreen has been developed in conjunction with a smartphone APP to enable the measure of the angle of trunk inclination (ATI) thus offering a convenient and reliable means to measure and screen for spinal deformities. The objective was to compare the reliability and accuracy of a Scolioscreen-smartphone combination, a smartphone alone, and a Scoliometer, for measuring the angle of trunk inclination in spinal deformities under blinded conditions for intra- and inter-observer analyses.MethodsA cohort of 39 patients with adolescent idiopathic scoliosis were recruited. Each had maximum ATI measured by 3 observers: attending spine surgeon, nurse, and parent presenting with patient. Two series of measurements were performed by each observer using Scolioscreen-smartphone, smartphone alone and Scoliometer. Intra-class correlation coefficients (ICC) from two-way mixed model based on absolute agreement were used to assess intra- and inter-observer reliability as well as consistency between measurement techniques.ResultsIntra- and inter-observer reliability for measuring maximum ATI was 0.94-0.89 with Scolioscreen-smartphone, decreased to 0.89-0.75 for smartphone alone, and was 0.95- 0.89 for Scoliometer. Considering Scoliometer measurement taken by surgeon the gold standard, there was excellent consistency with measurements from Scolioscreen-smartphone taken by surgeon (ICC = 0.99), nurse (ICC = 0.95), and parent (ICC = 0.91). Conversely, consistency decreased when surgeon (ICC = 0.86), nurse (ICC = 0.86) and parent (ICC = 0.85) used smartphone alone.ConclusionStudy shows the Scolioscreen-smartphone to overcome limitations associated with ATI measurements using smartphones alone. The Scolioscreen-smartphone provides a reliability and consistency similar to the gold standard (use of Scoliometer by spine surgeon) and enables a parent to take reliable measurements on their own thus offering an accessible and convenient tool for all to use.

Novel Hemi-staple for the Fusionless Correction of Pediatric Scoliosis: Influence on Intervertebral Discs and Growth Plates in a Porcine Model.

Study Design:In vivo porcine model utilized to evaluate the influence of an intravertebral fusionless growth modulating device (hemi-staple) on intervertebral disks and growth plates. Objective:To evaluate the radiographic and histologic changes in disks and growth plates with the purpose of measuring influence of the explored hemi-staple. Summary of Background Data:Fusionless growth modulation for the early treatment of scoliosis should insure the long-term viability of the intervertebral disk and successfully reduce or arrest local growth. A novel hemi-staple that proved effective in the control of coronal spinal alignment warranted further analyses of its influence on the disk health and growth-plate morphology. Methods:A hemi-staple that inhibited local vertebral growth exclusive of the disk was introduced over T5–T8 in 4 immature pigs (16 vertebrae; experimental), whereas 3 underwent surgery without instrumentation (sham) and 2 had no intervention (control). Three-month follow-up before animal euthanasia provided radiographic (disk height and health) and histologic (growth plate morphology, disk health, and type X collagen distribution) analyses. Results:No postoperative complications were experienced. Radiographic data returned inverse disk wedging (greater disk height adjacent to device, 2.6±0.7 mm compared with the noninstrumented side, 1.8±0.5 mm) in experimental segments and suggested disk viability. Histologic data confirmed device growth modulation through significant local reduction of growth plate hypertrophic zone (125.64±16.61 &mgr;m and 61.16±8.25 &mgr;m in noninstrumented and instrumented sections, respectively) and cell height (16.14±1.87 &mgr;m and 9.22±1.57 &mgr;m in noninstrumented and instrumented sections, respectively). A variability of disk health, dependant of device insertion location, was observed. Type X collagen was consistently identified in experimental growth plates and absent from intervertebral disks. Conclusions:Hemi-staples decreased growth plate hypertrophic zone and cell height, and, depending on device insertion site, showed positive signs of disk health sustainability. Spinal growth modulation achieved exclusive of disk compression, as practiced by this method, offers unique advantages over other fusionless techniques. This technique may provide a suitable and attractive alternative for the early treatment of idiopathic scoliosis.

Biomechanical Comparison of 2 Different Pedicle Screw Systems During the Surgical Correction of Adult Spinal Deformities

STUDY DESIGN A biomechanical spine model was used to evaluate the impact of screw design on screw-vertebra interface loading during simulated surgical corrections of adult scoliosis. OBJECTIVES To evaluate differences in screw-vertebra interface forces during adult scoliosis correction between favored angle (FA) screws with extension tabs and standard polyaxial screws while varying deformity severity and curve rigidity. SUMMARY OF BACKGROUND DATA Pedicle screws enable surgeons to safely and effectively realign spinal deformities. The risk of perioperative screw pullout increases when presented with adult deformities that have less flexible spines and lower bone mineral density. An FA screw with reduction tabs is believed to enable surgical techniques permitting load distribution on multiple screws, thereby reducing screw pullout potential. METHODS The researchers constructed 3 finite element spine models from adult scoliosis patients. Mechanical properties of intervertebral discs were modeled to reflect less flexible adult spines and their stiffness was varied to evaluate impact on screw-vertebra forces. Models simulated scoliosis surgery according to clinical data using FA or polyaxial screws. Forces measured at the screw-vertebra interface were monitored and compared for each patient with FA and then polyaxial screws. RESULTS Simulations using FA screws reduced screw-vertebra interface forces significantly compared with polyaxial screws. Favored angle screws caused 18%, 14%, and 16% reductions in peak forces and 29%, 35%, and 22% reductions in average forces compared with polyaxial screws for patients 1, 2, and 3, respectively. Favored angle screws also provided consistent relative reduction in average forces by 28% when varying properties of intervertebral discs among 8, 10, and 12 MPa. CONCLUSIONS Using a virtual finite element platform, FA screws reduced screw-vertebra interface forces encountered during simulated correction of less flexible adult scoliosis compared with standard polyaxial screws. These results show a potential benefit of using this modified screw design to reduce screw-vertebra forces and potential intraoperative pullout failures.

Frontiers in fascia research

Basic sciences are the backbone of every clear understanding of how the body is composed and how different structures and functions are connected with each other. It is obvious that there is a huge variability in human beings - not only in terms of the outer appearance such as measurements of height, weight, muscle mass and other physical properties, but also with respect to metabolic and functional parameters. This article highlights recent developments of research activities in the field of fascia sciences with a special emphasis on assessment strategies as the basis of further studies. Anatomical and histological studies show that fascial tissue is highly variable in terms of density, stiffness, and other parameters such as metabolic and humoral activity. Moreover, it encompasses nerves and harbours a system of micro-channels, also known as the primo vascular system. As ultrasound is a widely available method, its use is appealing not only for imaging of fascial structures, but also for thorough scientific analysis. Unlike most other imaging technologies, US has the advantage of real-time analysis of active or passive movements. In addition, other assessment methods for fascial tissue are discussed. In conclusion, fascial tissue plays an important role not only in functional anatomy, but also in evolutionary and molecular biology, sport, and exercise science as well as in numerous therapeutic approaches. A high density of nerves is found in fascial tissue. Knowledge of individual characteristics, especially by visualizing with ultrasound, leads to personalized therapeutic approaches, such as in pain therapy.

The Effects of a Home-Based Connective Tissue Targeting Therapy on Hip Development in Children With Cerebral Palsy: Six Case Reports

Hip subluxation in children with Cerebral Palsy (CP) has an incidence of 10-30 %, and children with severe CP having the highest incidence. The condition deteriorates if left untreated. Surgery is the most common method used in managing hip subluxation because standard conservative therapies do not improve it. Surgery may have to be repeated and comes at a biological cost to the child. A new home-based CAM, Advanced Biomechanical Rehabilitation (ABR), has shown encouraging results leading to improved spinal stability and stability in sitting in children with severe CP. This case report examines hip development over time in six children with severe CP in the ABR Program. Changes in their clinical picture and pelvic X-Rays are reported. ABR appeared to help stabilize and improve hip subluxation, resulting in these children not requiring further surgical intervention. These findings warrant further investigation of ABR as a noninvasive therapy for hip subluxation.