The FIND Program: Improving Follow-up of Incidental Imaging Findings.

Incidental findings are findings identified on imaging which are unrelated to the original reason for examination and require follow-up. The Radiology Finding Incidental Disease (FIND) Program was designed to track and improve follow-up of incidental imaging findings. The purpose of this study was to determine the frequency of incidental findings on cross-sectional imaging and the adherence to suggested follow-up of incidental findings prior to and after implementation of a structured reporting and tracking system. A retrospective analysis of 2000 patients with computed tomographic cross-sectional imaging was performed: 1000 patients prior to implementation of the FIND Program and 1000 patients 1 year after establishment of the program. Data collected included the frequency of incidental findings, inclusion of follow-up recommendations in the radiology report, and adherence to suggested follow-up. There was a higher rate of completion of recommended follow-up imaging in the post-implementation group (34/67, 50.7%) compared to the pre-implementation (16/52, 30.8%) (p = 0.03). Implementation of an incidental findings tracking program resulted in improved follow-up of incidental imaging findings. This has the potential to reduce the burden of clinically significant incidental findings possibly resulting in later presentation of advanced disease.

Smith-Petersen Versus Watson-Jones Approach Does Not Affect Quality of Open Reduction of Femoral Neck Fracture.

OBJECTIVE: To compare immediate quality of open reduction of femoral neck fractures by alternative surgical approaches. DESIGN: Retrospective cohort study. SETTING: Twelve Level 1 North American trauma centers. PATIENTS: Eighty adults 18-65 years of age with isolated, displaced, OTA/AO type 31-B2 or -B3 femoral neck fractures treated with internal fixation. INTERVENTION: Thirty-two modified Smith-Petersen anterior approaches versus 48 Watson-Jones anterolateral approaches for open reduction performed by fellowship-trained orthopaedic trauma surgeons. MAIN OUTCOME: Reduction quality as assessed by 3 senior orthopaedic traumatologists as "acceptable" or "unacceptable" on AP and lateral postoperative radiographs. RESULTS: No difference was observed in the rate of acceptable reduction by modified Smith-Petersen (81%) versus Watson-Jones (81%) approach (risk difference null, 95% confidence interval -17.4% to 17.4%, P = 1.00) with 90.4% panel agreement (Fleiss' weighted κ = 0.63, P < 0.01). Stratified analyses did not identify a significant difference in the rate of acceptable reduction between approaches when stratified by Pauwels angle, basicervical or transcervical fracture location, or posterior comminution. The Smith-Petersen approach afforded a better reduction when preoperative skeletal traction was not applied (RR = 1.67 [95% CI 1.10-2.52] vs. RR = 0.87 [95% CI 0.70-1.08], P = 0.006). CONCLUSIONS: No difference was observed in the quality of open reduction of displaced femoral neck fractures in young adults when a Watson-Jones anterolateral approach versus a modified Smith-Petersen anterior approach was performed by orthopaedic trauma surgeons. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Breast Arterial Calcifications: Reporting Preferences and Impact on Screening for Coronary Artery Disease.

OBJECTIVE: Breast arterial calcifications (BAC) have been shown to correlate with measures of coronary artery disease risk stratification, although reporting of BAC is optional by BI-RADS guidelines. The purpose of this study is to determine referring provider preferences in BAC reporting on mammography reports and if such reporting has any impact on patient management. METHODS: This study was approved by the local institutional review board. A voluntary eight-question survey regarding the preferences and outcomes of BAC reporting on mammography was distributed to 1085 primary care physicians, obstetrics and gynecologists, medical oncologists, and breast and general surgeons in our health system via a secure online platform. Data analysis including Pearson chi-square was performed with a P-value of <0.05 for significance. RESULTS: A response rate of 19.1% (207/1085) was attained, with 21/207 (10.1%) of respondents indicating they do not routinely order mammograms excluded from further analysis. A total of 62.4% (116/186) of ordering physicians indicated a preference for reporting of BAC in both the body and impression of the radiology report, with 82.3% (153/186) of respondents placing importance on the quantity of atherosclerotic calcifications. Most participants (148/186, 79.6%) reported that the presence of BAC would prompt further investigation for coronary artery disease and associated risk factors. CONCLUSION: The majority of responding physicians indicated a preference for detailed reporting of BAC and that such reporting would impact patient care. Understanding referring provider preferences regarding ancillary findings of BAC will allow for improved communication and value in mammography.

Open Reduction Is Associated With Greater Hazard of Early Reoperation After Internal Fixation of Displaced Femoral Neck Fractures in Adults 18-65 Years.

OBJECTIVES: To determine (1) which factors are associated with the choice to perform an open reduction and (2) by adjusting for these factors, if the choice of reduction method is associated with reoperation. DESIGN: Retrospective cohort study with radiograph and chart review. SETTING: Twelve Level 1 North American trauma centers. PATIENTS: Two hundred thirty-four adults 18-65 years of age with an isolated, displaced, OTA/AO type 31-B2 or type 31-B3 femoral neck fracture treated with internal fixation with minimum of 6-month follow-up or reoperation. Exclusion criteria were pathologic fractures, associated femoral head or shaft fractures, and primary arthroplasty. INTERVENTION: Open or closed reduction technique during internal fixation. MAIN OUTCOME: Cox proportional hazard of reoperation adjusting for propensity score for open reduction based on injury, demographic, and medical factors. Reduction quality was assessed by 3 senior orthopaedic traumatologists as "acceptable" or "unacceptable" on AP and lateral postoperative radiographs. RESULTS: Median follow-up was 1.5 years. One hundred six (45%) patients underwent open reduction. Reduction quality was not significantly affected by open versus closed approach (71% vs. 69% acceptable, P = 0.378). The propensity to receive an open reduction was associated with study center; younger age; male sex; no history of injection drug use, osteoporosis, or cerebrovascular disease; transcervical fracture location; posterior fracture comminution; and surgery within 12 hours. A total of 35 (33%) versus 28 (22%) reoperations occurred after open versus closed reduction (P = 0.056). Open reduction was associated with a 2.4-fold greater propensity-adjusted hazard of reoperation (95% confidence interval 1.3-4.4, P = 0.004). A total of 35 (15%) patients underwent subsequent total hip arthroplasty or hemiarthroplasty. CONCLUSIONS: Open reduction of displaced femoral neck fractures in nonelderly adults is associated with a greater hazard of reoperation without significantly improving reduction. Prospective randomized trials are indicated to confirm a causative effect of open versus closed reduction on outcomes after femoral neck fracture. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

In vivo remodeling of intervertebral discs in response to short- and long-term dynamic compression.

This study evaluated how dynamic compression induced changes in gene expression, tissue composition, and structural properties of the intervertebral disc using a rat tail model. We hypothesized that daily exposure to dynamic compression for short durations would result in anabolic remodeling with increased matrix protein expression and proteoglycan content, and that increased daily load exposure time and experiment duration would retain these changes but also accumulate changes representative of mild degeneration. Sprague-Dawley rats (n = 100) were instrumented with an Ilizarov-type device and divided into three dynamic compression (2 week-1.5 h/day, 2 week-8 h/day, 8 week-8 h/day at 1 MPa and 1 Hz) and two sham (2 week, 8 week) groups. Dynamic compression resulted in anabolic remodeling with increased matrix mRNA expression, minimal changes in catabolic genes or disc structure and stiffness, and increased glysosaminoglycans (GAG) content in the nucleus pulposus. Some accumulation of mild degeneration with 8 week-8 h included loss of annulus fibrosus GAG and disc height although 8-week shams also had loss of disc height, water content, and minor structural alterations. We conclude that dynamic compression is consistent with a notion of "healthy" loading that is able to maintain or promote matrix biosynthesis without substantially disrupting disc structural integrity. A slow accumulation of changes similar to human disc degeneration occurred when dynamic compression was applied for excessive durations, but this degenerative shift was mild when compared to static compression, bending, or other interventions that create greater structural disruption.

Dynamic compression effects on intervertebral disc mechanics and biology.

STUDY DESIGN: A bovine intervertebral disc organ culture model was used to study the effect of dynamic compression magnitude on mechanical behavior and measurement of biosynthesis rate, cell viability, and mRNA expression. OBJECTIVE: The objective of this study was to examine the effect of loading magnitude on intervertebral disc mechanics and biology in an organ culture model. SUMMARY OF BACKGROUND DATA: The in vivo and cell culture response of intervertebral disc cells to dynamic mechanical loading provides evidence the disc responds in a magnitude dependent manner. However, the ability to link mechanical behavior of the disc with biologic phenomena has been limited. A large animal organ culture system facilitates measurements of tissue mechanics and biologic response parameters on the same sample allowing a broader understanding of disc mechanobiology. METHODS: Bovine caudal intervertebral discs were placed in organ culture for 6 days and assigned to a static control or 1 of 2 dynamic compression loading protocols (0.2-1 MPa or 0.2-2.5 MPa) at 1 Hz for 1 hour for 5 days. Disc structure was assessed with measurements of dynamic modulus, creep, height loss, water content, and proteoglycan loss to the culture medium. Cellular responses were assessed through changes in cell viability, metabolism, and qRT-PCR analyses. RESULTS: Increasing magnitudes of compression increased disc modulus and creep; however, all mechanical parameters recovered each day. In the anulus, significant increases in gene expression for collagen I and a trend of increasing sulfate incorporation were observed. In the nucleus, increasing gene expression for collagen I and MMP3 was observed between magnitudes and between static controls and the lowest magnitude of loading. CONCLUSION: Results support the hypothesis that biologic remodeling precedes damage to the intervertebral disc structure, that compression is a healthy loading condition for the disc, and further support the link between applied loading and biologic remodeling.

In vivo intervertebral disc remodeling: kinetics of mRNA expression in response to a single loading event.

Kinetics of mRNA expression following a single loading event was measured using an in vivo rat tail model. Animals were instrumented and loaded in compression for 1.5 h at 1 MPa and 1 Hz. Real-time RT-PCR was used to measure mRNA levels 0, 8, 24 and 72 h after mechanical stimulation for genes associated with matrix proteins (aggrecan, collagen-I, collagen-II), proteases (MMP-2, MMP-3, MMP-13, ADAMTS-4), and their inhibitors (TIMP-1, TIMP-3) in anulus fibrosus and nucleus pulposus regions. Baseline mRNA levels were of greatest abundance for matrix proteins and lowest for proteases. The mRNA levels reached maximum levels 24 h following mechanical stimulation for the majority of genes evaluated, but some had maximum levels 8 and 72 h following loading. The mRNA levels returned to baseline levels for all genes in the nucleus 72 h following loading, but the majority of genes in the anulus remained upregulated. Results support a coordinated strategy of relative mRNA expression that varied over time beginning with inhibition of tissue breakdown, followed by synthesis of aggrecan and matrix degrading enzymes, and eventually collagen metabolism days following loading. Consequently, optimal time for tissue harvest for mRNA measurements depends on genes of interest. Results suggest attempts at anabolic remodeling must be given adequate time for metabolic processes and protein synthesis to occur, and that changes in TIMP and MMP levels may have greater potency in affecting structural protein abundance than direct changes in the structural protein messages. Results have important implications for disc remodeling and tissue engineering.

Different effects of static versus cyclic compressive loading on rat intervertebral disc height and water loss in vitro.

STUDY DESIGN: In vitro biomechanical study on rat caudal motion segments to evaluate association between compressive loading and water content under static and cyclic conditions. OBJECTIVE: To test hypotheses: 1) there is no difference in height loss and fluid (volume) loss of discs loaded in compression under cyclic (0.15-1.0 MPa) and static conditions with the same root-mean-square (RMS) magnitudes (0.575 MPa); and 2) after initial disc bulge, tissue water loss is directly proportional to height loss under static loading. SUMMARY OF BACKGROUND DATA: Disc degeneration affects water content, elastic and viscoelastic behaviors. There is limited understanding of the association between transient water loss and viscoelastic creep in a controlled in vitro environment where inferences may be made regarding mechanisms of viscoelasticity. METHODS: A total of 126 caudal motion segments from 21 Wistar rats were tested in compression using 1 of 6 protocols: Static loading at 1.0 MPa for 9, 90, and 900 minutes, Cyclic loading at 0.15 to 1.0 MPa/1 Hz for 90 minutes, Mid-Static loading at 0.575 MPa for 90 minutes, and control. Water content was then measured in anulus and nucleus regions. RESULTS: Percent water loss was significantly greater in nucleus than anulus regions, suggesting some water redistribution, with average values under 1 MPa static loading of 23.0% and 14.9% after 90 minutes and 26.9% and 17.6% after 900 minutes, respectively. Cyclic loading resulted in significantly greater height loss (0.506 +/- 0.108 mm) than static loading with the same RMS value (0.402 +/- 0.096 mm), but not significantly less than static loading at peak value (0.539 +/- 0.122 mm). Significant and strong correlations were found between percent water loss and disc height loss, suggesting water was lost through volume decrease. CONCLUSION: Peak magnitude of cyclic compression and not RMS value was most important in determining height change and water loss, likely due to differences between disc creep and recovery rates. Water redistribution from nucleus to anulus occurred under loading consistent with an initial elastic compression (and associated disc bulge) followed by a reduction in disc volume over time.

Characterization of an in vitro intervertebral disc organ culture system.

Intervertebral disc organ culture has the capacity to control mechanical and chemical boundary conditions while keeping the tissue largely intact, and allowing interventions that would be impossible or unethical on animal studies. Recent studies on ex vivo organ culture has mostly involved small animals, or been limited to development and validation studies. In this study, bovine caudal discs were used. The large animal model design ensures that sufficient tissue is available for measurement of multiple dependent variables on the same disc, and a similar aspect ratio, diffusion distance, composition and rate of proteoglycan synthesis to human lumbar discs. The first goal of this study was to refine a set of dependent variables capable of characterizing the response of the intervertebral disc to culturing and to develop a technique to measure cell viability in all three regions of the disc. The second goal was to use these variables to compare static and diurnal loading as a method of maintaining intervertebral disc structure, composition, and cell metabolism similar to the in vivo state. Static (0.2 MPa) and diurnal loading (0.1 and 0.3 MPa alternating at 12 h intervals) were applied and intervertebral discs were examined after 4 or 8 days with dependent variables including changes in geometry (disc height and diameter), composition (tissue water content, tissue proteoglycan content and proteoglycan content lost to the culture media), cell viability and metabolism (proteoglycan synthesis). Results indicate that there was a decrease in disc height and water content after culture regardless of culture duration or loading condition. Cell viability significantly decreased with culture duration in the inner annulus and nucleus; however, a significant reduction in cell viability for the diurnal versus static loading condition was only observed after 8 days in the nucleus region. No significant differences were seen in viability of the outer annulus region with time, or in any loading groups. We conclude that our system is capable of keeping bovine caudal discs alive for at least 8 days without significant changes in GAG content, or cell metabolism, and that static loading was slightly better able to maintain cell viability than diurnal loading. This system offers promise for the future studies on large intervertebral discs requiring measurements of multiple mechanical and biological dependent variables on the same tissue.

Measurements of proteoglycan and water content distribution in human lumbar intervertebral discs.

STUDY DESIGN: Study of regional variations in composition in a sample of 9 mildly to moderately degenerated human intervertebral discs. OBJECTIVE: The aim of this study was to obtain proteoglycan distribution in human lumbar discs with high position resolution in the: 1) sagittal, 2) coronal, and 3) axial directions. SUMMARY OF BACKGROUND DATA: Regional variation in disc proteoglycan content has only been reported in coronal sections in a small number of discs and with low spatial resolution in the sagittal direction, and has not been reported in the axial direction. METHODS: Each of 9 human L2-L3 or L3-L4 lumbar discs (age, 53-56 years) were dissected into 36 to 41 specimens using a rectangular cutting die, measured for water content and analyzed for glycosaminoglycan content using the dimethylmethylene blue dye binding assay. RESULTS: The intervertebral discs were mildly to moderately degenerated. They had glycosaminoglycan content ranging approximately 40 to 600 microg/mg dry tissue, with largest values in the nucleus and lowest in the outer anulus. In general, posterior regions had greater glycosaminoglycan content than anterior regions, although values were not as high as in the nucleus. Small variations in glycosaminoglycan content in the axial direction were observed with the largest values in the center, although this variation was small compared with radial variations. Water content results followed similar trends as glycosaminoglycan content with average values ranging from approximately 66% to 86%. CONCLUSIONS: A refined map of proteoglycan content is presented with 3 important findings. First, sagittal variations were distinct from coronal variations. Second, the proteoglycan content was not uniform across the nucleus regions. Third, some specimens had localized variations in proteoglycan and water contents suggestive of focal damage and degeneration.

Role of endplates in contributing to compression behaviors of motion segments and intervertebral discs.

The purpose of this study was to gain an improved understanding of the mechanical behavior of the intervertebral disc in the presence and absence of the vertebral endplates. Mechanical behaviors of rat caudal motion segments, vertebrae and isolated disc explants under two different permeability conditions were investigated and viscoelastic behaviors were evaluated using a stretched-exponential function to describe creep and recovery behaviors. The results demonstrated that both vertebrae and discs underwent significant deformations in the motion segment even under relatively low-loading conditions. Secondly, disruption of the collagenous network had minimal impact on equilibrium deformations of disc explants as compared to disc deformations occurring in the motion segments provided that vertebral deformations were accounted for; however, differences in endplate permeability conditions had a significant effect on viscoelastic behaviors. Creep occurred more quickly than recovery for motion segment and explant specimens. In addition, disc explants and motion segments both exhibited non-recoverable deformations under axial compression under low- and high-loading conditions. Results have important implications for interpreting the role of vertebral endplates in contributing to disc mechanical behaviors and direct application to mechanobiology studies involving external loading to rodent tail intervertebral discs.

A Removable Precision Device for In-Vivo Mechanical Compression of Rat Tail Intervertebral Discs.

The rat tail intervertebral disc has emerged as an important model to examine the mechanisms for mechanically induced degeneration and remodeling. Previous methods used to apply high precision axial compressive loading to a rat tail intervertebral disc in vivo either required anesthesia, or the permanent mounting of a loading device to the animal, and were not well described in the literature. Therefore, a new device to apply compressive loading to the rat tail intervertebral disc was developed and validated. The rat tail compressive loading system utilized a pneumatically driven device weighing 18 g, and was capable of delivering a 12.6 N sinusoidal or square waveform at frequencies up to 1.0 Hz. The system improved on previous methods in its modular construction, relative ease of fabrication, compatibility with existing tail model technology and overall cost effectiveness. The removable system eliminated the need for anesthesia and through a modular, cost effective, design allowed for the simultaneous loading of multiple animals. This system expanded the ability to accurately, ethically, and efficiently apply dynamic compressive loads to the rat tail intervertebral disc for extended periods of time in order to address questions related to disc mechanobiology.

Effects of mechanical loading on intervertebral disc metabolism in vivo.

The overall goal of this work is to define more clearly which mechanical loading conditions are associated with accelerated disc degeneration. This article briefly reviews recent studies describing the effects of mechanical loading on the metabolism of intervertebral disc cells and defines hypothetical models that provide a framework for quantitative relationships between mechanical loading and disc-cell metabolism. Disc cells respond to mechanical loading in a manner that depends on loading magnitude, frequency, and duration. On the basis of the current data, four models have been proposed to describe the effects of continuous loading on cellular metabolism: (1) on/off response, in which messenger ribonucleic acid (mRNA) transcription remains altered for the duration of loading; (2) maintenance, characterized by an initial change in mRNA levels with return to baseline levels; (3) adaptation, in which mRNA transcription is altered and remains at a new steady state; and (4) no response. In addition, five hypothetical mechanisms that describe the long-term consequences of these metabolic changes on disc-remodeling are presented. The transient nature of gene expression along with enzyme activation/inhibition is associated with changes at the protein level. The hypothetical models presented provide a framework for obtaining quantitative relationships between mechanical loading, gene expression, and changes at the compositional level; however, additional factors, such as regulatory mechanisms, must also be considered when describing disc-remodeling. A more quantitative relationship between mechanical loading effects and the metabolic response of the disc will contribute to injury prevention, facilitate more effective rehabilitation treatments, and help realize the potential of biologic and tissue engineering approaches toward disc repair.

Mechanical damage to the intervertebral disc annulus fibrosus subjected to tensile loading.

Damage of the annulus fibrosus is implicated in common spinal pathologies. The objective of this study was to obtain a quantitative relationship between both the number of cycles and the magnitude of tensile strain resulting in damage to the annulus fibrosus. Four rectangular tensile specimens oriented in the circumferential direction were harvested from the outer annulus of 8 bovine caudal discs (n = 32) and subjected to one of four tensile testing protocols: (i) ultimate tensile strain (UTS) test; (ii) baseline cyclic test with 4 series of 400 cycles of baseline cyclic loading (peak strain = 20% UTS); (iii & iv) acute and fatigue damage cyclic tests consisting of 4 x 400 cycles of baseline cyclic loading with intermittent loading to 1 and 100 cycles, respectively, with peak tensile strain of 40%, 60%, and 80% UTS. Normalized peak stress for all mechanically loaded specimens was reduced from 0.89 to 0.11 of the baseline control levels, and depended on the magnitude of damaging strain and number of cycles at that damaging strain. Baseline, acute, and fatigue protocols resulted in permanent deformation of 3.5%, 6.7% and 9.6% elongation, respectively. Damage to the laminate structure of the annulus in the absence of biochemical activity in this study was assessed using histology, transmission electron microscopy, and biochemical measurements and was most likely a result of separation of annulus layers (i.e., delamination). Permanent elongation and stress reduction in the annulus may manifest in the motion segment as sub-catastrophic damage including increased neutral zone, disc bulging, and loss of nucleus pulposus pressure. The preparation of rectangular tensile strip specimens required cutting of collagen fibers and may influence absolute values of results, however, it is not expected to affect the comparisons between loading groups or dose-response reported.