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Computed tomography (CT) is a common modality employed for musculoskeletal imaging. Conventional CT techniques are useful for the assessment of trauma in detection, characterization and surgical planning of complex fractures. CT arthrography can depict internal derangement lesions and impact medical decision making of orthopedic providers. In oncology, CT can have a role in the characterization of bone tumors and may elucidate soft tissue mineralization patterns. Several advances in CT technology have led to a variety of acquisition techniques with distinct clinical applications. These include four-dimensional CT, which allows examination of joints during motion; cone-beam CT, which allows examination during physiological weight-bearing conditions; dual-energy CT, which allows material decomposition useful in musculoskeletal deposition disorders (e.g., gout) and bone marrow edema detection; and photon-counting CT, which provides increased spatial resolution, decreased radiation, and material decomposition compared to standard multi-detector CT systems due to its ability to directly translate X-ray photon energies into electrical signals. Advanced acquisition techniques provide higher spatial resolution scans capable of enhanced bony microarchitecture and bone mineral density assessment. Together, these CT acquisition techniques will continue to play a substantial role in the practices of orthopedics, rheumatology, metabolic bone, oncology, and interventional radiology. [ABSTRACT FROM AUTHOR]

Summary: Poor bone quality is a risk factor for complications after spinal fusion surgery. This study investigated pre-operative bone quality in postmenopausal women undergoing spine fusion and found that those with small bones, thinner cortices and surgeries involving more vertebral levels were at highest risk for complications. Purpose: Spinal fusion is one of the most common surgeries performed worldwide. While skeletal complications are common, underlying skeletal deficits are often missed by pre-operative DXA due to artifact from spinal pathology. This prospective cohort study investigated pre-operative bone quality using high resolution peripheral CT (HRpQCT) and its relation to post-operative outcomes in postmenopausal women, a population that may be at particular risk for skeletal complications. We hypothesized that women with low volumetric BMD (vBMD) and abnormal microarchitecture would have higher rates of post-operative complications. Methods: Pre-operative imaging included areal BMD (aBMD) by DXA, cortical and trabecular vBMD and microarchitecture of the radius and tibia by high resolution peripheral CT. Intra-operative bone quality was subjectively graded based on resistance to pedicle screw insertion. Post-operative complications were assessed by radiographs and CTs. Results: Among 50 women enrolled (age 65 years), mean spine aBMD was normal and 35% had osteoporosis by DXA at any site. Low aBMD and vBMD were associated with "poor" subjective intra-operative quality. Skeletal complications occurred in 46% over a median follow-up of 15 months. In Cox proportional models, complications were associated with greater number of surgical levels (HR 1.19 95% CI 1.06–1.34), smaller tibia total area (HR 1.67 95% CI1.16–2.44) and lower tibial cortical thickness (HR 1.35 95% CI 1.05–1.75; model p < 0.01). Conclusion: Women with smaller bones, thinner cortices and procedures involving a greater number of vertebrae were at highest risk for post-operative complications, providing insights into surgical and skeletal risk factors for complications in this population. [ABSTRACT FROM AUTHOR]

Purpose: The goals were to ascertain if differences in imaging/clinical characteristics between women and men were associated with differences in fusion for lumbar degenerative spondylolisthesis. Methods: Patients had preoperative standing radiographs, CT scans, and intraoperative fluoroscopic images. Symptoms and comorbidity were obtained from patients; procedure (fusion-surgery or decompression-alone) was obtained from intraoperative records. With fusion surgery as the dependent variable, men and women were compared in multivariable logistic regression models with clinical/imaging characteristics as independent variables. The sample was dichotomized, and analyses were repeated with separate models for men and women. Results: For 380 patients (mean age 67, 61% women), women had greater translation, listhesis angle, lordosis, and pelvic incidence, and less diastasis and disc height (all p ≤ 0.03). The rate of fusion was higher for women (78% vs. 65%; OR 1.9, p = 0.008). Clinical/imaging variables were associated with fusion in separate models for men and women. Among women, in the final multivariable model, less comorbidity (OR 0.5, p = 0.05), greater diastasis (OR 1.6, p = 0.03), and less anterior disc height (OR 0.8, p = 0.0007) were associated with fusion. Among men, in the final multivariable model, opioid use (OR 4.1, p = 0.02), greater translation (OR 1.4, p = 0.0003), and greater diastasis (OR 2.4, p = 0.0002) were associated with fusion. Conclusions: There were differences in imaging characteristics between men and women, and women were more likely to undergo fusion. Differences in fusion within groups indicate that decisions for fusion were based on composite assessments of clinical and imaging characteristics that varied between men and women. [ABSTRACT FROM AUTHOR]

Purpose: The vertebral bone quality (VBQ) score based on magnetic resonance imaging (MRI) was introduced as a bone quality marker in the lumbar spine. Prior studies showed that it could be utilized as a predictor of osteoporotic fracture or complications after instrumented spine surgery. The objective of this study was to evaluate the correlation between VBQ scores and bone mineral density (BMD) measured by quantitative computer tomography (QCT) in the cervical spine. Methods: Preoperative cervical CT and sagittal T1-weighted MRIs from patients undergoing ACDF were retrospectively reviewed and included. The VBQ score in each cervical level was calculated by dividing the signal intensity of the vertebral body by the signal intensity of the cerebrospinal fluid on midsagittal T1-weighted MRI images and correlated with QCT measurements of the C2–T1 vertebral bodies. A total of 102 patients (37.3% female) were included. Results: VBQ values of C2–T1 vertebrae strongly correlated with each other. C2 showed the highest VBQ value [Median (range) 2.33 (1.33, 4.23)] and T1 showed the lowest VBQ value [Median (range) 1.64 (0.81, 3.88)]. There was significant weak to moderate negative correlations between and VBQ Scores for all levels [C2: p < 0.001; C3: p < 0.001; C4: p < 0.001; C5: p < 0.004; C6: p < 0.001; C7: p < 0.025; T1: p < 0.001]. Conclusion: Our results indicate that cervical VBQ scores may be insufficient in the estimation of BMDs, which might limit their clinical application. Additional studies are recommended to determine the utility of VBQ and QCT BMD to evaluate their potential use as bone status markers. [ABSTRACT FROM AUTHOR]

This study aimed at quantifying trabecular volumetric bone mineral density (vBMD) at the external occipital protuberance (EOP) and the upper cervical spine. A retrospective review of patients who underwent non‐contrast enhanced computed tomography of the cervical spine that included the occipital bone up to the EOP between 2007 and 2020 was conducted. Measurements of trabecular vBMD were performed in the occipital midline area, with the region of interest extending 4.5 mm above and below the center of the EOP, as well as the C1 lateral masses and the C2 vertebral body using asynchronous quantitative computed tomography. Eighty‐six patients (female, 37.2%) were included for analysis. The patient population was 81.4% Caucasian with a mean ± SD age of 62.3 ± 13.1 years. Total bone thickness at the EOP was 16.7 ± 3.4 mm, with a ratio of trabecular to total bone thickness of 0.44. Trabecular vBMD (mean ± SD) was significantly higher at the EOP than at C1 and C2 (EOP = 612.3 ± 145.8 mg/cm3, C1 average = 290.3 ± 66.5 mg/cm3, C2 = 305.8 ± 78.8 mg/cm3; p < 0.001). A significant strong correlation between trabecular vBMD of C1 and C2 was observed (r = 0.744; p < 0.001), but only low correlations between the EOP and C1 (r = 0.295; p = 0.008) and C2 (r = 0.413; p < 0.001). In individuals > 65 years of age, cervical vBMD was significantly lower, but remained high at the EOP. Clinical significance: Trabecular vBMD at the EOP is significantly higher than at the upper cervical vertebrae and remains high in older populations. Together with morphological information about the occipital bone, these results might be helpful for occipitocervical fixation when deciding about uni‐ or bicortical screw placement at the EOP. [ABSTRACT FROM AUTHOR]

The objective of this study is to determine the bone mineral density (BMD) changes in adjacent vertebra following anterior cervical discectomy and fusion (ACDF). Consecutive patients undergoing ACDF with available preoperative and postoperative computed tomography (CT) imaging were included. Quantitative CT measurements of screw‐free cervical and first thoracic vertebra were performed. Comparisons between pre‐ and postoperative BMD in the vertebrae one or two levels above the upper instrumented vertebra (UIV + 1, UIV + 2) and one level below the lowest instrumented vertebra (LIV + 1) were assessed. Seventy‐two patients (men, 66.7%) met the inclusion criteria. The patient population was 91.7% Caucasian with a mean age of 55.0 years. The mean interval (±SD) between surgery and secondary CT was 157 ± 23 days. Preoperative BMD (±SD) in UIV + 1 was 300.6 ± 66.2 mg/cm3. There was a significant BMD loss of 1.5% at UIV + 1 after surgery, resulting in a postoperative BMD of 296.2 ± 64.8 mg/cm3 (p =.029). At UIV + 2 and LIV + 1, no significant differences between pre‐ and postoperative BMD (304.7 ± 75.7 mg/cm3 vs. 299.8 ± 74.3 mg/cm3, 197.3 ± 50.4 mg/cm3 vs. 200.8 ± 48.7 mg/cm3, p =.113 and p =.078, respectively) were observed. Clinical significance Our results demonstrate a small BMD decrease of 1.5% at UIV + 1. This suggests that the effect of ACDF surgery on the adjacent levels might be smaller compared to the previously described lumbar BMD loss of 10%–20% following posterior lumbar fusion procedures. [ABSTRACT FROM AUTHOR]

Purpose: High body mass index (BMI) is positively correlated with bone mineral density (BMD) in healthy adults; however, the effect of BMI on regional segmental BMDs in the axial skeleton is unclear. In addition, obese patients often have glucose intolerance and patients with lumbar spine pathology commonly have a history of epidural steroid injections (ESIs). The purpose of this study is to evaluate the effect of these patient factors on regional differences in BMD measured by quantitative computed tomography (QCT) in a lumbar fusion patient cohort. Methods: The data were obtained from a database comprised of clinical and preoperative CT data from 296 patients who underwent primary posterior lumbar spinal fusion from 2014 to 2017. QCT-vBMDs of L1 to L5, S1 body, and sacral alae were measured. Multivariate linear regression analyses were performed with setting vBMDs as the response variables. As explanatory variables, age, sex, race, current smoking, categorized BMI, diabetes, and ESI were chosen a priori. Results: A total of 260 patients were included in the final analysis. Multivariate analyses demonstrated that obese and morbidly obese patients had significantly higher vBMD in the sacral alae (SA). Diabetes showed independent positive associations with vBMDs in L1, L2, and the SA. Additionally, patients with an ESI history demonstrated significantly lower vBMD in the SA. Conclusions: Our results demonstrate that obesity, diabetes, and epidural steroids affected vBMD differently by lumbosacral spine region. The vBMD of the SA appeared to be more sensitive to various patient factors than other lumbar regions. [ABSTRACT FROM AUTHOR]

Purpose: Quantitative computed tomography (QCT) is an alternate imaging method to dual X-ray absorptiometry to measure bone mineral density (BMD). One advantage of QCT is that it allows site-specific volumetric BMD (vBMD) measurements in a small region. In this study, we utilized site-specific, endplate vBMD (EP-vBMD) as a potential predictive marker of severe cage subsidence in standalone lateral lumbar interbody fusion (SA-LLIF) patients and conducted a retrospective comparative study between EP-vBMD and trabecular vBMDs (Tb-vBMD) in the vertebrae.Methods: Patients undergoing SA-LLIF from 2007 to 2016 were retrospectively reviewed. EP-vBMD was defined as the average of the upper and lower endplate volumetric BMDs measured in cortical and trabecular bone included in a 5-mm area of interest beneath the cage contact surfaces. We compared Tb-vBMDs and EP-vBMDs between disk levels that had severe cage subsidence and levels with no severe subsidence.Results: Both EP-vBMD and Tb-vBMD could be measured in 210 levels of 96 patients. Severe cage subsidence was observed in 58 levels in 38 patients. Median (IQR) Tb-vBMD was 120.5 mg/cm3 (100.8-153.7) in the non-severe subsidence group and 117.9 mg/cm3 (90.6-149.5) in the severe subsidence group (p = 0.393), whereas EP-vBMD was significantly lower in the severe subsidence group than the non-severe subsidence group (non-severe subsidence 257.4 mg/cm3 (216.3-299.4), severe subsidence 233.5 mg/cm3 (193.4-273.3), p = 0.026).Conclusion: We introduced a novel site-specific vBMD measurement for cage subsidence risk assessment. Our results showed that EP-vBMD was a reproducible measurement and appeared more predictive for severe cage subsidence after SA-LLIF than Tb-vBMD. These slides can be retrieved under Electronic Supplementary Material. [ABSTRACT FROM AUTHOR]

Purpose: To test the inter-observer and inter-method reliability among the measures suggesting patellofemoral joint disorder on both CT and MRI in the same subject and find possible association with internal derangements of the patellofemoral joint on MRI.Methods: Institutional review board approval was obtained with waiver of the informed consent in this HIPPA-compliant study. CT and MRI were evaluated in 32 knees in 32 respective subjects (10 men/22 women, mean age 38 ± 19 years). Three trained observers assessed tibial tuberosity-trochlear groove (TT-TG) distance, trochlear angle and trochlear depth on both CT and MRI. Intra-class correlation coefficient (ICC) was used to evaluate inter-observer and inter-method reliability. Two radiologists' consensus reading was used to evaluate their association with soft tissue abnormalities of the patellofemoral joint. Chi-square test was used to assess the statistical significance of the qualitative variables.Results: There was an excellent inter-observer reliability (ICC for CT >0.89 and for MRI >0.90) and inter-method reliability (ICC >0.86) for all the quantitative measurements. There was a significant association between increased TT-TG distance value on MR imaging and lateral facet patellar cartilage abnormality and joint effusion (p < 0.05).Conclusion: Quantitative trochlear parameters can be reliably calculated on MRI, and an abnormal TT-TG distance is the most useful measurement among various static MR imaging parameters to correlate with patellar chondrosis and joint effusion. TT-TG distance should be reported in patellofemoral pain syndrome patients.Level Of Evidence: IV. [ABSTRACT FROM AUTHOR]

Computed tomography (CT) offers tremendous advantages in the evaluation of femoroacetabular impingement (FAI), as it allows precise measurements of osseous landmarks and relationships preoperatively and postoperatively. Important femoral measurements to make on CT include the alpha angle, modified beta angle, femoral version, femoral head-neck offset, and femoral neck-shaft angle. Key acetabular measurements to make on CT include the coronal and sagittal center-edge angles, the Tonnis angle, and the acetabular version. Three main settings in which CT imaging is utilized for the evaluation of FAI are preoperative surgical planning using 3-dimensional modeling, the assessment of persistent hip pain after hip arthroscopy or a definitive surgical procedure, and the evaluation of patients requiring revision surgery. Extra-articular hip impingement syndromes, including ischiofemoral impingement, subspine impingement, and trochanteric-pelvic impingement, are increasingly recognized as important causes of atypical hip pain, often with delayed diagnosis due to nonspecific presentation and inadequate clinical and imaging workup. [ABSTRACT FROM AUTHOR]

Purpose: The high contrast resolution and absent ionizing radiation of interventional magnetic resonance imaging (MRI) can be advantageous for paravertebral sympathetic nerve plexus injections. We assessed the feasibility and technical performance of MRI-guided paravertebral sympathetic injections utilizing augmented reality navigation and 1.5 T MRI scanner.Methods: A total of 23 bilateral injections of the thoracic (8/23, 35%), lumbar (8/23, 35%), and hypogastric (7/23, 30%) paravertebral sympathetic plexus were prospectively planned in twelve human cadavers using a 1.5 Tesla (T) MRI scanner and augmented reality navigation system. MRI-conditional needles were used. Gadolinium-DTPA-enhanced saline was injected. Outcome variables included the number of control magnetic resonance images, target error of the needle tip, punctures of critical nontarget structures, distribution of the injected fluid, and procedure length.Results: Augmented-reality navigated MRI guidance at 1.5 T provided detailed anatomical visualization for successful targeting of the paravertebral space, needle placement, and perineural paravertebral injections in 46 of 46 targets (100%). A mean of 2 images (range, 1-5 images) were required to control needle placement. Changes of the needle trajectory occurred in 9 of 46 targets (20%) and changes of needle advancement occurred in 6 of 46 targets (13%), which were statistically not related to spinal regions (P = 0.728 and P = 0.86, respectively) and cadaver sizes (P = 0.893 and P = 0.859, respectively). The mean error of the needle tip was 3.9±1.7 mm. There were no punctures of critical nontarget structures. The mean procedure length was 33±12 min.Conclusion: 1.5 T augmented reality-navigated interventional MRI can provide accurate imaging guidance for perineural injections of the thoracic, lumbar, and hypogastric sympathetic plexus. [ABSTRACT FROM AUTHOR]

Background: Dual-energy computed tomography (DECT) is a new diagnostic tool for gout, but its sensitivity has not been established. Our goal was to assess the sensitivity of DECT for the detection of monosodium urate (MSU) deposits in non-tophaceous and tophaceous gout, both at the level of the patient and that of the individual joint or lesion.Methods: DECT was performed on 11 patients with crystal-proven non-tophaceous gout and 10 with tophaceous gout and included both the upper and lower extremities in 20/21 patients. DECT images were simultaneously acquired at 80 and 140 kV and then processed on a workstation with proprietary software using a two-material decomposition algorithm. MSU deposits were color coded as green by the software and fused onto grey-scale CT images. The number and location of these deposits was tallied independently by two DECT-trained radiologists blinded to the clinical characteristics of the patient. Sensitivity of DECT was defined as the proportion of patients with a confirmed diagnosis of gout which was correctly identified as such by the imaging technique. All patients provided informed consent to participate in this IRB-approved study.Results: MSU deposits were detected by DECT in ≥1 joint area in 7/11 (64 %) patients with non-tophaceous gout, but were only detected in 3/12 (25 %) joints proven by aspiration to be affected with gout. Inclusion of the upper extremity joints in the scanning protocol did not improve sensitivity. All 10 patients with tophaceous gout had MSU deposits evident by DECT. The sensitivity of DECT for individual gouty erosions was assessed in 3 patients with extensive foot involvement. MSU deposits were detected by DECT within or immediately adjacent to 13/26 (50 %) erosions.Conclusions: A DECT protocol that includes all lower extremity joints has moderate sensitivity in non-tophaceous and high sensitivity in tophaceous gout. However, DECT has lower sensitivity when restricted to individual crystal-proven gouty joints in non-tophaceous disease or individual erosive lesions in tophaceous gout. The detection of MSU deposits by DECT relates to their size and density and the detection parameters of the DECT scanner and adjustment of the latter might improve sensitivity. [ABSTRACT FROM AUTHOR]

Background Context: Sacral fractures are a rare but potentially devastating complication. Long-fusion constructs, including the sacrum, that do not extend to the pelvis may result in sacral fractures. Besides established risk factors including gender, age, and number of levels fused, body mass index (BMI), pelvic parameters, and bone mineral density (BMD) have also been proposed as potential risk factors for postoperative sacral fractures. The literature supporting this, however, is limited.Purpose: The aim of the present study was to assess whether preoperative pelvic parameters, BMI, or BMD of patients with sacral fracture are different compared with age, gender, and fusion level-matched non-fracture controls.Study Design/setting: This is a case-control study.Patient Sample: Patients undergoing posterior instrumented fusion at a single academic institution between 2002 and 2016 were included in the study.Outcome Measures: The outcome measure was occurrence of a postoperative sacral fracture.Methods: Patients with sacral fractures after posterior instrumented spinal fusion, including the sacrum, were retrospectively identified and matched 2:1 with non-fracture controls based on gender, age, and number of levels fused. Patients with concurrent spinopelvic fixation or missing preoperative computed tomography (CT) imaging were excluded. Preoperative sagittal balance was assessed using lateral radiographs. Quantitative computed tomography (QCT) assessment included standard measurements at L1/L2 and additional experimental measurements of the S1 body and sacral ala.Results: Twenty-one patients with sacral fracture were matched to non-fracture controls. The majority of the patients with sacral fracture was female (76.2%) and of advanced age (mean 66.4 years). Fracture and control groups were well matched with respect to gender, age, and number of levels fused. Standard measurements at L1/L2 showed no significant difference in BMD between the fracture and the control groups (109.9 mg/cm3 vs. 116.4 mg/cm3, p=.414). Similarly, there was no significant BMD differences between the groups using the experimental measurements of the S1 body (183.6 mg/cm3 vs. 176.2 mg/cm3, p=.567) and the sacral ala (8.9 mg/cm3 vs. 4.8 mg/cm3, p=.616). Mean preoperative pelvic incidence-lumbar lordosis mismatch and pelvic tilt were not significantly different between the groups. Univariate conditional logistic regression analysis revealed that the odds of experiencing a sacral fracture was approximately six times higher for obese patients compared with normal or underweight patients. After controlling for BMI in multivariate conditional logistic regression models, BMD was still not significantly associated with the odds of experiencing sacral fractures.Conclusions: To our knowledge, this is the first study to assess the association of preoperative BMD measured by QCT, pelvic parameters, and BMI with postoperative sacral fractures in a large patient cohort. Interestingly, our data do not show any difference in preoperative pelvic parameters and BMD between the groups. This is in line with previous reports that indicate only a few patients with sacral fracture after fusion surgery have clear evidence of osteoporosis. Bone mineral density as a measure of bone quantity, rather than bone quality, may not be as important in these fractures as previously thought. Obesity, however, was associated with higher odds of experiencing postoperative sacral fractures. The present study thereby challenges the widespread concept that obesity is a protective factor against fractures in the elderly. In summary, our results suggest that BMI and gender, more than pelvic parameters and BMD, are risk factors for postoperative sacral fractures. [ABSTRACT FROM AUTHOR]

Study Design.: Cross-sectional preoperative and intraoperative imaging study of L4–L5 lumbar degenerative spondylolisthesis (LDS). Objective.: To determine if alternate imaging modalities would identify LDS instability that did not meet the criteria for instability based on comparison of flexion and extension radiographs. Summary of Background Data.: Pain may limit full flexion and extension maneuvers and thereby lead to underreporting of true dynamic translation and angulation in LDS. Alternate imaging pairs may identify instability missed by flexion-extension. Materials and Methods.: Consecutive patients scheduled for surgery for single-level L4–L5 LDS had preoperative standing radiographs in the lateral, flexion, and extension positions, supine computed tomography (CT) scans, and intraoperative fluoroscopic images in the supine and prone positions after anesthesia but before incision. Instability was defined as translation ≥3.5 mm or angulation ≥11° between the following pairs of images: (1) flexion-extension; (2) CT-lateral; (3) lateral-intraoperative supine; (4) lateral-intraoperative prone; and (5) intraoperative supine-prone. Results.: Of 240 patients (mean age 68 y, 54% women) 15 (6%) met the criteria for instability by flexion-extension, and 225 were classified as stable. Of these 225, another 84 patients (35% of total enrollment) were reclassified as unstable by comparison of CT-lateral images (21 patients) and by lateral-intraoperative images (63 patients). Nine of the 15 patients diagnosed with instability by flexion-extension had fusion (60%), and 68 of the 84 patients reclassified as unstable by other imaging pairs had fusion (81%) (P =0.07). The 84 reclassified patients were more likely to undergo fusion compared with the 141 patients who persistently remained classified as stable (odds ratio=2.6, 95% CI: 1.4-4.9, P =0.004). Conclusions.: Our study provides evidence that flexion and extension radiographs underreport the dynamic extent of LDS and therefore should not be solely relied upon to ascertain instability. These findings have implications for how instability should be established and the extent of surgery that is indicated. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective descriptive study.Objective: The aim of this study was to create topographical maps of occipital bone thickness and venous sinus (VS) presence to assess the risks of screw insertion in four commercially available occipital plates.Summary Of Background Data: Craniocervical junction instability and deformity are serious pathological conditions that require posterior fixation of the occipital bone to the cervical vertebrae. Insertion of occipital bone screws requires evaluation of both occipital bone thickness for effective internal fixation and intracranial VS presence for vascular injury prevention. Despite the surgical risks, there is a paucity of research on safe screw placement.Methods: We created a matrix of 231 standardized measurement points to analyze the occipital bone thickness and VS presence in cervical spine CT angiograms. These measurements were used to create topographical maps of occipital bone thickness and likelihood of VS presence, which we then compared to the screw hole configurations of four occipital plates.Results: Hundred patients were assessed. Maximum occipital bone thickness of 13.9 ± 3.3 mm was midline in the occipital bone, 45 mm from the foramen magnum, around the external occipital protuberance (EOP). Regions with thicknesses >8 mm were 2 cm lateral to the EOP at the level of the superior nuchal line and 2.5 cm inferior to the EOP. The area with the highest VS presence rate was around the EOP and the superior nuchal line. The right transverse VS was more prominent in both sexes.Conclusion: There is a limited area of the occipital bone with thicknesses for enough screw purchase. Previous studies have shown 8 mm as the minimum screw length to reduce the risk of implant failure. In our analysis, only "T"-shaped plates had configurations with thicknesses >8 mm for each screw hole. For every screw hole in the analyzed occipital plates, there was a possibility of VS presence ranging from 8% to 33%.Level of Evidence: 5. [ABSTRACT FROM AUTHOR]

Background Context: The thoracic spine is a common location for vertebral fractures as well as instrumentation failure after long spinal fusion procedures. The association between those complications and bone mineral density (BMD) are well recognized. Due to the overlying sternum and ribs in the thoracic spine, projectional BMD assessment tools such as dual energy x-ray absorptiometry (DXA) are limited to the lumbar spine. Quantitative computed tomography circumvents several shortcomings of DXA and allows for level-specific BMD measurements. Studies comprehensively quantifying BMD of the entire thoracic spine in patients undergoing spine surgery are limited.Purpose: The objective of this study was: (1) to assess the reliability of thoracic QCT measurements, (2) to determine possible level-specific BMD variation throughout the thoracic spine and (3) to assess the correlation between BMDs of the T1-T12 spinal levels.Study Design/setting: Cross-sectional observation study.Patient Sample: Patients undergoing spine surgery from 2016-2020 at a single, academic institution with available preoperative CT imaging of the thoracic spine were included in this study.Outcome Measures: The outcome measure was BMD measured by QCT.Methods: Patients undergoing spine surgery from 2016-2020 at a single, academic institution with available preoperative CT imaging of the thoracic spine were included in this study. Subjects with previous instrumentation at any thoracic level, concurrent vertebral fractures, a Cobb angle of more than 20 degrees, or incomplete thoracic spine CT imaging were excluded. Asynchronous quantitative computed tomography (QCT) measurements of T1-T12 were performed. To assess inter- and intra-observer reliability, a validation study was performed on 120 vertebrae in 10 randomly selected patients. The interclass correlation coefficient (ICC) was calculated. A pairwise comparison of BMD was conducted and correlations between each thoracic level were evaluated. The statistical significance level was set at p<.05.Results: 60 patients (men, 51.7%) met inclusion criteria. The study population was 90% Caucasian with a mean age of 62.2 years and a mean BMI of 30.2 kg/m2. The inter- and intra-observer reliability of the thoracic QCT measurements was excellent (ICC of 0.97 and 0.97, respectively). The trabecular BMD was highest in the upper thoracic spine and decreased in the caudal direction (T1 = 182.3 mg/cm3, T2 = 168.1 mg/cm3, T3 = 163.5 mg/cm3, T4 = 164.7 mg/cm3, T5 = 161.4 mg/cm3, T6 = 152.5 mg/cm3, T7 = 143.5 mg/cm3, T8 = 141.3 mg/cm3, T9 = 143.5 mg/cm3, T10 = 145.1 mg/cm3, T11 = 145.3 mg/cm3, T12 = 133.6 mg/cm3). The BMD of all thoracic levels cranial to T6 was statistically higher than the BMD of all levels caudal to T6 (p < .001). Nonetheless, significant correlations in BMD among all measured thoracic levels were observed, with a Pearson's correlation coefficient ranging from 0.74 to 0.97.Conclusions: There is significant regional BMD variation in the thoracic spine depending on spinal level. This BMD variation might contribute to several clinically relevant phenomena. First, vertebral fractures occur most commonly at the thoracolumbar junction including T12. In addition to mechanical reasons, these fractures might be partially attributed to thoracic BMD that is lowest at T12. Second, the optimal upper instrumented vertebra (UIV) for stopping long fusions to the sacrum and pelvis is controversial. The BMD of surgically relevant upper thoracic stopping points (T2-T4) was significantly higher than the BMD of lower thoracic stopping points (T10-T12). Besides stress concentration at the relatively mobile lower thoracic segments, the low BMD at these levels might contribute to previously suggested higher rates of junctional failures with short fusions. [ABSTRACT FROM AUTHOR]

Background Context: Clinically, the association between bone mineral density (BMD) and surgical instrumentation efficacy is well recognized. Although several studies have quantified the BMD of the human lumbar spine, comprehensive BMD data for the cervical spine is limited. The few available studies included young and healthy patient samples, which may not represent the typical cervical fusion patient. Currently no large scale study provides detailed BMD information of the cervical and first thoracic vertebrae in patients undergoing anterior cervical spine surgery.Purpose: The objective of this study was to determine possible trabecular BMD variations throughout the cervical spine and first thoracic vertebra in patients undergoing anterior cervical discectomy and fusion (ACDF) and to assess the correlation between BMDs of the spinal levels C1-T1.Study Design/setting: This is a retrospective case series.Patient Sample: Patients undergoing ACDF from 2015 to 2018 at a single, academic institution with available preoperative CT imaging were included in this study.Outcome Measures: The outcome measure was BMD measured by QCT.Methods: Patients that underwent ACDF from 2015 to 2018 at a single, academic institution were included in this study. Subjects with previous cervical instrumentation or missing/incomplete preoperative cervical spine CT imaging were excluded. Asynchronous quantitative computed tomography (QCT) measurements of the lateral masses of C1 and the C2-T1 vertebral bodies were performed. For this purpose, an elliptical region of interest that consisted exclusively of trabecular bone was selected. Any apparent sclerotic levels that might affect trabecular QCT measurements were excluded from the final analysis. Interobserver reliability of measurements was assessed by calculating the interclass correlation coefficients (ICC). Pairwise comparison of BMD was performed and correlations between the various cervical levels were evaluated. The statistical significance level was set at p<.05.Results: In all, 194 patients (men, 62.9%) met inclusion criteria. The patient population was 91.2% Caucasian with a mean age of 55.9 years and mean BMI of 28.2 kg/m2. The ICC of cervical QCT measurements was excellent (ICC 0.92). The trabecular BMD was highest in the mid-cervical spine (C4) and decreased in the caudal direction (C1 average=253.3 mg/cm3, C2=276.6 mg/cm3, C3=272.2 mg/cm3, C4=283.5 mg/cm3, C5=265.1 mg/cm3, C6=235.3 mg/cm3, C7=216.8 mg/cm3, T1=184.4 mg/cm3). The BMD of C7 and T1 was significantly lower than those of all other levels. Nonetheless, significant correlations in BMD among all measured levels were observed, with a Pearson's correlation coefficient ranging from 0.507 to 0.885.Conclusions: To the authors' knowledge this is the largest study assessing trabecular BMD of the entire cervical spine and first thoracic vertebra by QCT. The patient sample consisted of patients undergoing ACDF, which adds to the clinical relevance of the findings. Knowledge of BMD variation in the cervical spine might be useful to surgeons utilizing anterior cervical spine plate and screw systems. Due to the significant variation in cervical BMD, procedures involving instrumentation at lower density caudal levels might potentially benefit from a modification in instrumentation or surgical technique to achieve results similar to more cephalad levels. [ABSTRACT FROM AUTHOR]

There have been some reports on the association between spinal balance parameters and regional bone mineral density (BMD), but the results are controversial. The purpose of this study is to evaluate the relationship between spinopelvic parameters and regional volumetric BMDs (vBMDs) measured by quantitative computed tomography (QCT) in the lumbosacral region of patients undergoing lumbar fusion surgery. The data of consecutive patients undergoing posterior lumbar spinal fusion with preoperative computed tomography was reviewed. QCT measurements were conducted in L1–S1 vertebral trabecular bone. The associations between spinopelvic sagittal parameters and vBMDs were evaluated. Multivariate analyses adjusted with age, gender, race, and body mass index were conducted with vBMD as the response variable. A total of 144 patients were included in the final analyses. Mean age (± standard deviation) was 65.4 ± 11.8 years. Mean vBMD in L1 (± standard deviation) was 118.3 ± 37.4 mg/cm3. After adjusting by cofactors, lumbar lordosis was negatively associated with vBMDs in all levels from L1 to L5 (% regression coefficients and adjusted R 2 values: L1, –0.438, 0.268; L2, –0.556, 0.296; L3, –0.608, 0.362; L4, –0.554, 0.228; L5, –0.424, 0.194), but not in S1. Sacral slope was negatively associated with vBMD only at L4 (% coefficient, –0.588; R 2, 0.208). Other parameters were not significantly associated with vBMDs at any levels. Higher lumbar lordosis was associated with lower vBMDs in all lumbar spine levels. Our results suggest that BMD is affected not only by metabolic factors but also by the mechanical environment. Further longitudinal studies are needed to elucidate this effect of vBMD on clinical outcomes. [ABSTRACT FROM AUTHOR]

Background Context: It has been reported that degenerative disc disease (DDD) is associated with higher spinal bone mineral density (BMD) based on previous studies that used dual X-ray absorptiometry (DXA). However, DDD is often associated with proliferative bone changes and can lead to an overestimation of BMD measured with DXA. Trabecular volumetric BMD (vBMD) in the vertebral body measured with quantitative computed tomography (QCT) is less affected by those changes and can be a favorable alternative to DXA for patients with degenerative spinal changes.Purpose: The purpose of this study is to investigate the effect of DDD on regional trabecular vBMDs in the vertebral body measured by QCT.Study Design/setting: Cross-sectional observational study at a single academic institution.Patients Sample: Consecutive patients undergoing posterior lumbar spinal fusion between 2014 and 2017 who had a routine preoperative CT scan and magnetic resonance imaging (MRI) within a 90-day interval.Outcome Measures: Regional trabecular vBMDs in the vertebral body by QCT.Methods: QCT measurements were conducted in L1-S1 vertebral trabecular bone. Any apparent sclerotic lesions that might affect vBMD values were excluded from the region of interest. The vBMDs of each level were defined as the average vBMD of the upper and lower vertebrae. To evaluate DDD, Pfirrmann grade, Modic grade, total end plate score, and vacuum phenomenon were documented. Univariate regression analysis and multivariate analyses with a linear mixed model adjusted with individual variability of segmental vBMDs were conducted with vBMD as the response variable.Results: Of 143 patients and 715 disc levels, 125 patients and 596 discs met our inclusion criteria. Mean vBMD (±standard deviation [SD]) of all levels was 119.0±39.6 mg/cm3. After adjusting for all covariates, Pfirrmann grade was not an independent contributor to vBMD, but the presence of any Modic change (type 1, β=6.8, p≤.001; type 2, β=6.7, p<.001; type 3, β=43.6, p<.001), high TEPS (score 10-12, β=14.2, p<.001), or vacuum phenomenon (β=9.0, p<.001) was shown to be independent contributors to vBMD.Conclusions: Our results showed that the presence of certain end plate lesions (Modic changes and high TEPS) on MRI was significantly associated with increased regional QCT-vBMDs in the vertebral body, but no significant association was observed with disc nucleus pathology, unless it was associated with a vacuum phenomenon. When end plate lesions with Modic changes and high TEPS are present at the measuring level, care must be taken to interpret vBMD values, which might be overestimations even if the trabecular area appears normal. [ABSTRACT FROM AUTHOR]

Background Context: Quantitative computed tomography (QCT) of the lumbar spine is used as an alternative to dual-energy X-ray absorptiometry in assessing bone mineral density (BMD). The average BMD of L1-L2 is the standard reportable metric used for diagnostic purposes according to current recommendations. The density of L1 and L2 has also been proposed as a reference value for the remaining lumbosacral vertebrae and is commonly used as a surrogate marker for overall bone health. Since regional BMD differences within the spine have been proposed, it is unclear if the L1-L2 average correlates with the remainder of the lumbosacral spine.Purpose: The aim of this study was to determine possible BMD variations throughout the lumbosacral spine in patients undergoing lumbar fusion and to assess the correlation between the clinically used L1-L2 average and the remaining lumbosacral vertebral levels.Study Design/setting: This is a retrospective case series.Patient Sample: Patients undergoing posterior lumbar spinal fusion from 2014 to 2017 at a single, academic institution with available preoperative CT imaging were included in this study.Outcome Measures: The outcome measure was BMD measured by QCT.Methods: Standard QCT measurements at the L1 and L2 vertebra and additional experimental measurements of L3, L4, L5, and S1 were performed. Subjects with missing preoperative lumbar spine CT imaging were excluded. The correlations between the L1-L2 average and the other vertebral bodies of the lumbosacral spine (L3, L4, L5, S1) were evaluated.Results: In total, 296 consecutive patients (55.4% female, mean age of 63.1 years) with available preoperative CT were included. The vertebral BMD values showed a gradual decrease from L1 to L3 and increase from L4 to S1 (L1=118.8 mg/cm3, L2=116.6 mg/cm3, L3=112.5 mg/cm3, L4=122.4 mg/cm3, L5=135.3 mg/cm3, S1=157.4 mg/cm3). There was strong correlation between the L1-L2 average and the average of the other lumbosacral vertebrae (L3-S1) with a Pearson's correlation coefficient (r=0.85). We also analyzed the correlation between the L1-L2 average and each individual lumbosacral vertebra. Similar relationships were observed (r value, 0.67-0.87), with the strongest correlation between the L1-L2 average and L3 (r=0.87).Conclusions: Our data demonstrate regional BMD differences throughout the lumbosacral spine. Nevertheless, there is high correlation between the clinically used L1-L2 average and the BMD values in the other lumbosacral vertebrae. We, therefore, conclude the standard clinically used L1-L2 BMD average is a useful bone quantity measure of the entire lumbosacral spine in patients undergoing lumbar spinal fusion. [ABSTRACT FROM AUTHOR]

Lumbar fusion surgery has become a standard procedure in spine surgery and commonly includes posterior placement of pedicle screws. Bone quality is a critical factor that affects pedicle screw purchase, whereas the role of paraspinal musculature is less well understood. Pedicle screw loosening is a devastating complication often leading to revision surgery. However, the relationship of paraspinal muscles and the pedicle is unknown. Therefore, we aimed to determine the relationship between paraspinal muscle composition and bony microstructure of the lumbar. Lumbar fusion surgery has become a standard procedure in spine surgery and commonly includes posterior placement of pedicle screws. Bone quality is a critical factor that affects pedicle screw purchase, whereas the role of paraspinal musculature is less well understood. Pedicle screw loosening is a devastating complication often leading to revision surgery. However, the relationship of paraspinal muscles and the pedicle is unknown. The aim of the study was to determine the relationship between paraspinal muscle composition and bony microstructure of the lumbar pedicle. Prospective study. Twenty-four patients undergoing open posterior lumbar fusion at a single academic institution. Preoperative lumbar magnetic resonance imaging (MRI) scans were evaluated using a dedicated software for a quantitative assessment of the cross-sectional area (CSA), the functional cross-sectional area (fCSA), and the proportion of intramuscular fat. The regions of interest were the psoas muscle and the paraspinal muscles at the superior endplate of the L4 level. Left and right side of the muscle groups were averaged and normalized by the patient's height (cm2/m2). Intraoperative bone biopsies of the lumbar pedicle were obtained and analyzed with microscopic computed tomography (microCT) scans. Parameters of cortical (Cort) and trabecular (Trab) bone were collected and the following parameters assessed: bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), connectivity density (CD), specific bone surface (BS/BV), apparent density (AD) and total mineral density (TMD). The relationship between microCT parameters and paraspinal CSA, fCSA and fat infiltration were determined by the Spearman correlation. The relationship between microCT parameters and paraspinal CSA, fCSA and fat infiltration were determined by the Spearman correlation. Statistical significance was defined as p<0.05. Twenty-four patients (50% female) with a median age of 62.2 years (IQR: 54.7-68.2) and a mean (±SD) BMI of 29.8 (6) kg/m2 were analyzed. fCSA of the paraspinal muscles showed significant positive correlations with BV/TV Trab (r=0.582, p=0.003), CD Trab (r=0.639; p < 0.001), Tb.N Trab (r=0.469, p=0.021), Tb.Th (r=0.405, p=0.0049) and AD Trab (r=0.510, p=0.011). Cortical bone parameters also demonstrated a significant positive correlation with fCSA (BV/TVCort: r= 0.551, p=0.005; ADCort: r=0.551, p=0.005). fCSA of the psoas showed no correlation with cortical or trabecular microCT parameters, but fat infiltration of the psoas was negatively correlated with TMD Cort (r=-663, p < 0.001). This study provides evidence that the bone microstructure of the lumbar pedicle is significantly correlated with the fCSA of the paraspinal musculature. Whether this finding is related to mechanical coupling or to biochemical processes cannot be conclusively stated. However, this finding gives us further insight in the mutual interactions between lumbar vertebral bone and paraspinal muscles. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background Context: Provocative discography, an invasive diagnostic procedure involving disc puncture with pressurization, is a test for presumptive discogenic pain in the lumbar spine. The clinical validity of this test is unproven. Data from multiple animal studies confirm that disc puncture causes early disc degeneration. A recent study identified radiographic disc degeneration on magnetic resonance imaging (MRI) performed 10 years later in human subjects exposed to provocative discography. The clinical effect of this disc degeneration after provocative discography is unknown.Purpose: The aim of this study was to investigate the clinical effects of lumbar provocative discography on patients subjected to this evaluation method.Study Design/setting: A prospective, 10-year matched cohort study.Patient Sample: Subjects (n=75) without current low back pain (LBP) problems were recruited to participate in a study of provocative discography at the L3-S1 discs. A closely matched control cohort was simultaneously recruited to undergo a similar evaluation except for discography injections.Outcome Measures: The primary outcome variables were diagnostic imaging events and lumbar disc surgery events. The secondary outcome variables were serious LBP events, disability events, and medical visits.Methods: The discography subjects and control subjects were followed by serial protocol evaluations at 1, 2, 5, and 10 years after enrollment. The lumbar disc surgery events and diagnostic imaging (computed tomography (CT) or MRI) events were recorded. In addition, the interval and cumulative lumbar spine events were recorded.Results: Of the 150 subjects enrolled, 71 discography subjects and 72 control subjects completed the baseline evaluation. At 10-year follow-up, 57 discography and 53 control subjects completed all interval surveillance evaluations. There were 16 lumbar surgeries in the discography group, compared with four in the control group. Medical visits, CT/MRI examinations, work loss, and prolonged back pain episodes were all more frequent in the discography group compared with control subjects.Conclusion: The disc puncture and pressurized injection performed during provocative discography can increase the risk of clinical disc problems in exposed patients. [ABSTRACT FROM AUTHOR]

Purpose: To investigate differences in joint space width (JSW) and meniscal extrusion (ME) between non-weight bearing (NWB) and weight bearing (WB) examinations of knee joints with medial compartment osteoarthritis (OA) using a cone-beam CT (CBCT) extremity imaging system.Materials and Methods: In this IRB approved prospective study, informed consent was obtained for 17 patients symptomatic for OA (11 F,6 M; 31-78 years, mean 56 years) and 18 asymptomatic controls (0 F,18 M; 29-48 years, mean 38.5 years) enrolled for CBCT exams in NWB and WB positions. Three independent observers measured medial tibiofemoral JSW and ME. Measurements were compared between NWB and WB images using paired Wilcoxon signed-rank sum test.Results: OA subjects exhibited a statistically significant reduction in JSW between NWB and WB scans (average JSW(NWB)(OA)=2.1 mm and JSW(WB)(OA)=1.5 mm, p=0.016) and increase in ME (average ME(NWB)(OA)=6.9 mm and ME(WB)(OA)=8.2 mm, p=0.018)). For non-OA subjects, the change in JSW and ME between NWB and WB exams was reduced (average JSW(NWB)(nonOA)=3.7 mm and JSW(WB)(nonOA)=3.4 mm; average ME(NWB)(nonOA)=2.6 mm and ME(WB)(nonOA)=2.7 mm) and was not statistically significant. Inter-observer agreement was evaluated using Bland-Altman limits of agreement, with good agreement for all measurements (correlation coefficient 0.89-0.98).Conclusion: The ability to conduct NWB and WB exams in CBCT with a dose profile that is favorable in comparison to multidetector CT (MDCT) and with image quality sufficient for morphological analysis of joint space narrowing and meniscal extrusion could provide a valuable tool for OA diagnosis and treatment assessment. [ABSTRACT FROM AUTHOR]

Low muscle volume, also called sarcopenia, is a common condition of aging with a prevalence between 1 and 29% in populations over the age of 50 years. Previous studies have demonstrated evidence that both osteoporosis and sarcopenia coexist, called osteosarcopenia, and these patients are at greater risk for falls, fractures and mortality. In osteoporotic post-menopausal female patients, the prevalence of sarcopenia is around 50%. Recent studies showed that sarcopenic subjects had a 4-fold higher risk of coexisting osteoporosis compared with nonsarcopenic individuals. However, a limited number of studies have been conducted in spine surgery patients. The aim of this study is to investigate the associations between the lean muscle volume (LMV) in paraspinal and proas muscle on MRI and quantitative computed tomography (QCT) volumetric bone mineral density (vBMD) in the lumbosacral region. A cross-sectional analysis of a prospectively maintained database at a single academic institution. Patients undergoing posterior lumbar fusion surgery between 2014-2020. Volumetric BMD measured by QCT in the lumbar spine and sacral ala. We reviewed an institutional database of posterior lumbar fusion patients. Patients who had ongoing antiosteoporotic therapy with bisphosphonate, denosumab or teriparatide were excluded. Muscle measurements were conducted utilizing a free software program (ITK-SNAP version 3.8) setting regions of interest (ROI) in the bilateral psoas and paraspinal (erector spinae and multifundus) muscles on preoperative T2-weighted axial MR images at the mid-L3 level. The area of fat-free muscle (LMV: lean muscle volume) was calculated using a custom written program on Matlab™ (MATLAB version 2019a, The MathWorks, Inc, Natick, MA, USA). QCT measurements were performed on preoperative CT scans using the Mindways QCT Pro Software (Mindways Software, Inc., Austin, TX, USA). QCT-vBMDs in the standard L1-L2 and bilateral sacral ala were analyzed. Pearson's correlation and linear regression analyses adjusting with age and BMI were performed. Since muscle volume is strongly affected by biological sex, we stratified by sex for all analyses. Statistical significance was set <0.05. Out of 144 patients, 30 patients were excluded due to QCT incompatible CTs or poor quality MRIs for muscle volume measurements. An additional 9 patients were excluded due to ongoing anti-osteoporotic drug therapy. A total of 105 patients (50 male and 55 female) were included in the final analysis. In female patients, there were statistically significant mild to moderate positive correlations between L1-L2 vBMD and LMV in paraspinal and psoas muscles, as well as sacral ala vBMD and paraspinal LMV, whereas there was no significant correlation in male patients. After the adjustment with age and BMI, high paraspinal LMV was an independent factor for high sacral ala vBMD (β=0.04 (95%CI: 0.00-0.14), p=0.040) and high psoas LMV was significantly associated with high L1-L2 vBMD (β=0.04 (95%CI: 0.01-0.14), p=0.025). Our results demonstrated that higher lean muscle volume was significantly associated with higher vBMD in the lumbosacral lesions in women. This association was not observed in men. This might indicate gender differences should be considered for the assessment of osteosarcopenia in spine surgery patients. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

The importance of bone quality assessment in spine surgery is well recognized. The current gold standard for assessing bone mineral density is dual-energy X-ray absorptiometry (DEXA), however the majority of patients undergoing spinal fusion do not have preoperatively available DEXA data. Furthermore, DEXA has been shown to overestimate BMD in patients with spinal degenerative disease and obesity. Consequently, alternative radiographic measurements using data routinely gathered during preoperative evaluation of spine patients have been explored for the evaluation of bone quality and fracture risk. Opportunistic quantitative computed tomography and more recently the MRI-based vertebral bone quality (VBQ) score both have been shown to correlate with DEXA T-scores and predict osteoporotic fractures. However, to date the correlation between those two modalities has not been studied. The objective of this study was to assess whether the recently described novel VBQ score can predict the prevalence of QCT based osteopenia/osteoporosis and to evaluate the correlation between VBQ and spine QCT BMD measurements. Retrospective study of lumbar spinal fusion patients from a single, academic institution. Patients undergoing lumbar spinal fusion from 2014-2019 with available preoperative CT and T1-weighted MRIs of the lumbar spine. VBQ correlation to BMD. For BMD assessment, asynchronous quantitative computed tomography (QCT) measurements of L1-L2 were performed. An elliptical region of interest was placed anteriorly in the trabecular bone at mid-vertebral height and displaced from the vertebral cortex. The average BMD of L1-L2 was calculated and patients were categorized as either normal BMD (>120 mg/cm3) or osteopenic/osteoporotic (<=120 mg/cm3) based on the definition by the American College of Radiology. As previously described, the VBQ measurements were performed by placing circular regions of interest within the medullary portions of the vertebral bodies of L1-L4 and within the cerebrospinal fluid space at the level of L3 on a midsagittal T1-weighted MRI image. The VBQ score was then calculated by dividing the median signal intensity of the L1-L4 vertebral bodies by the signal intensity of the cerebrospinal fluid at the L3 level. To assess inter-observer reliability of the VBQ measurements, a validation study was performed on 37 randomly selected patients. The interclass correlation coefficient (ICC) was calculated. Demographic data and the VBQ score were compared between the normal and osteopenic/group. To determine the area-under-curve (AUC) of the VBQ score as a predictor of osteopenia/osteoporosis receiver operating characteristic (ROC) analysis was performed. VBQ scores were compared with QCT BMD using Pearson's correlation. The statistical significance level was set at p<0.05. A total of 198 patients (53% female) were included in the study. The mean age was 62 years and the mean BMI was 28.2 kg/m2. The inter-observer reliability of the VBQ measurements was excellent (ICC of 0.90; 95% confidence interval: 0.82, 0.95). When comparing the patients with normal QCT BMD to those with osteopenia/osteoporosis, no significant differences existed in terms of sex, race, and BMI. However, the patients with osteopenia/osteoporosis were significantly older compared to the patients with normal BMD (64.9 vs 56.7 years, p<0.0001). The osteopenic/osteoporotic group had significantly higher VBQ scores (2.6 vs 2.2, p<0.0001). ROC analysis revealed that the VBQ score predicts the presence of osteopenia/osteoporosis based on QCT with an accuracy of 71% (p<0.0001). The VBQ score showed a statistically significant moderate correlation with QCT BMD (correlation coefficient = -0.358, 95% CI -0.473 - -0.23, p<0.001). We found that the VBQ score significantly differentiates patients with normal BMD vs osteopenic/osteoporotic BMD based on QCT. However, the correlation between both modalities was only moderate suggesting VBQ might not measure bone density only. Due to the fact that QCT and more recently VBQ scores have both been shown to predict osteoporotic fractures, the weak correlation of the two modalities suggests that VBQ might not solely be a measurement of bone density, but rather bone quality. Since the two modalities seem to reflect different properties of bone, VBQ may be an interesting adjunct to clinically performed bone density measurements, rather than a substitution. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Previous studies reported that lumbar spine surgery has a negative effect on bone mineral density (BMD) in the lumbar spine. Dual X-ray absorptiometry (DXA) was generally used for following BMD change in these studie. However, DXA has several limitations for measuring BMD in the vertebrae with morphological changes and metal implants, which are often associated with lumbar spine surgery. Also, it is still unclear if this BMD change is caused by a local mechanical effect or a systemic physiological insult associated with the surgery. To investigate the change of BMDs in multiple adjacent vertebrae utilizing quantitative computed tomography (QCT). Retrospective cohort study at a single academic institution. Consecutive patients who underwent posterior lumbar spine surgery with instrumentation between 2014-2017 and had both preoperative and secondary postoperative computed tomography of the lumbar spine between 6 to 12 months. Regional trabecular vBMDs in the vertebral body by QCT. Institutional ethics board approval was obtained for this study. Volumetric bone mineral density (vBMD) measurements by QCT were conducted in L1 to S1 vertebral trabecular bone. The change of vBMD in the vertebrae one or two-level above the upper instrumented vertebra (UIV+1, UIV+2) and one level below the lower instrumented vertebra (LIV+1) were analyzed. Statistical analyses were conducted utilizing paired t-test, one-way/repeated-measures ANOVA, and Pearson's correlation test. The statistical significance level was set at p<0.05. A total of 91 patients met our inclusion criteria. Mean age (&± SD [range]) was 61.9 & 11.9; 55.6% of the patients were female. Median interval between the surgery and the secondary CT was 248 (180-364) days. Volumetric BMD (&± SD) in UIV+1 was 113.1 & ± 32.6 mg/cm &>3 & preoperatively and 102.4 & ± 32.2 mg/cm3 (percent change:-10.5 & ± 12.6%) postoperatively (p <0.001). No correlation was observed between percent vBMD change in UIV+1 and interval between operation and postoperative CT (r=0.15, p=0.15). This trend of vBMD change was similar regardless of UIV level and number of fused level. The change of vBMDs in UIV+2 and LIV+1 appeared similar as UIV+1 (UIV+2: -11.9 & ± 12.3%, p=0.19,LIV+1: -7.2 & ± 20.7%, p=0.40). Posterior lumbar fusion surgery negatively affected the regional vBMDs measured by QCT in adjacent levels. BMDs in UIV+1, UIV+2, and LIV+1 were equally affected by the surgery. Our finding suggests that the postoperative decrease of regional BMDs in the lumbar spine dominantly occurs in the early postoperative phase (within 6 months) and a systemic effect has a greater role, rather than a regional mechanical one, in this postoperative BMD decline. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT Quantitative computed tomography (QCT) of the lumbar spine is used as an alternative to DXA in assessing bone mineral density (BMD). Clinically, a BMD average of L1/L2 is commonly used as a surrogate marker for overall bone health. Since significant regional BMD differences within the spine have been described, it is unclear if the L1/L2 average is an accurate bone quantity measure of the entire lumbosacral spine. PURPOSE The aim of this study was to assess the agreement between the clinically used L1/L2 BMD average and the other lumbosacral vertebral levels. STUDY DESIGN/SETTING A quantitative computed tomography study. PATIENT SAMPLE A total of 296 consecutive patients undergoing posterior lumbar spinal fusion from 2014 to 2017 at a single, academic institution. OUTCOME MEASURES Bone mineral density. METHODS Patients that underwent posterior lumbar spinal fusion from 2014 to 2017 at a single, academic institution were included in this study. Subjects with missing preoperative lumbar spine CT imaging were excluded. Standard QCT measurements at the L1 and L2 vertebra and additional experimental measurements of L3, L4, L5 and S1 were performed. The correlations between L1–L2 average and the other vertebral bodies of the lumbosacral spine (L3, L4, L5, and S1) were evaluated. RESULTS A total of 296 patients (women, 55.4%) met inclusion criteria. The patient population was 88.5% Caucasian with a mean age of 63.1years and mean BMI of 28.0 kg/m2. The vertebral BMD values showed a gradual decrease from L1 to L3 and subsequently increased from L4 to S1 (L1=118.8 mg/cm3, L2=116.6 mg/cm3, L3=112.5 mg/cm3, L4=122.4 mg/cm3, L5=135.3 mg/cm3, S1=157.4 mg/cm3). Our data showed strong correlation between the L1/L2 average and the average of the other lumbosacral vertebrae (L3–S1) with a Pearson's correlation coefficient, r=0.85. We also analyzed the correlation between the L1/L2 average and each individual lumbosacral vertebra. Similar relationships were observed (r value, 0.67–0.87) with the strongest correlation between the L1/L2 average and L3. CONCLUSIONS Our data demonstrates considerable regional BMD throughout the lumbosacral spine. Nevertheless, there is high concordance between the clinically used L1/L2 BMD average and the BMD values in the other lumbosacral vertebrae. As the closest vertebra to the standard measurement site, L3 showed the strongest individual correlation to the L1/L2 average. Although still strongly correlated, Pearson's correlation coefficients were smaller for the L4, L5 and S1 vertebra. This might be of importance, since the majority of patients in our cohort underwent fusion procedures at L4–L5 (71.3%) and/or L5–S1 (44.9%). In summary, the L1/L2 BMD average is a useful bone quantity measure of the entire lumbosacral spine in patients undergoing posterior lumbar spinal fusion. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT Quantitative computed tomography (QCT) is increasingly used for clinically diagnosing osteopenia and osteoporosis. In contrast to dual X-ray absorptiometry (DXA) which uses a two-dimensional projection, QCT provides a true volumetric bone mineral density (BMD) measurement. Certain conditions like spinal degeneration, abdominal aortic calcification, and other sclerotic lesions can lead to an overestimation of BMD by DXA. Similarly, QCT measurements can be affected by degenerative or sclerotic vertebral body changes if inadvertently included in the field during the measurement process. It remains unclear if excluding pathologic bone regions in the selected field allows for more accurate BMD measurements. PURPOSE The aim of this study was to assess whether BMD measured from pathologic levels is different than BMD derived from nonpathologic levels in paired, matched controls. STUDY DESIGN/SETTING Case-control study. PATIENT SAMPLE A total of 296 consecutive patients undergoing posterior lumbar spinal fusion from 2014 to 2017 at a single, academic institution. OUTCOME MEASURES Bone mineral density. METHODS Patients undergoing posterior lumbar spinal fusion from 2014 to 2017 at a single, academic institution with available preoperative lumbar spine CT imaging were included. QCT measurements of all lumbar and the first sacral vertebra were performed on all patients. Pathologic levels were defined by referencing operated levels from surgical records. Degenerative or sclerotic bone regions at pathologic levels were avoided during the measurement process to minimize overestimation of bone density in the vertebral body. Due to known differences in BMD at different levels in the lumbosacral spine, comparisons between pathologic and normal levels within the same patient are not possible. To overcome this limitation, matched normal-pathologic measurements at the same lumbosacral level were identified in matched patient-pairs. Patients were matched 1:1 based on gender, age (+/−5yrs), BMI (+/−5), and race. One or more normal-pathologic matched levels were identified from each patient pair. Differences between normal and pathologic levels were assessed using two-tailed paired t -tests with significance set at P<.05. RESULTS Seventy-seven matched patient pairs (154 patients) were isolated from a cohort of 296 patients treated surgically for lumbar spine pathology. Patients not matched were excluded due to inability to match on all four matching criteria. From the 77 patient pairs, 152 matched normal-pathologic levels were identified for analysis. The mean (SD) for normal and pathologic levels was 140.4 mg/cm3 (54.13) and 143.0 mg/cm3 (49.04), respectively. Paired statistical analyses revealed no significant difference between groups (P=.563). CONCLUSIONS Our data demonstrates no difference in BMD measured at pathologic and nonpathologic vertebra at the same lumbar or sacral levels in paired patients matched based on age, gender, BMI and race. When using the recommended methodology for QCT measurements including the avoidance of degenerative and/or sclerotic regions, BMD can be accurately measured at pathologic levels. Lumbar degenerative changes are known to adversely impact the sensitivity and specificity of DXA for diagnosing osteopenia and osteoporosis. Our findings suggest that unlike DXA BMD measurements, lumbar QCT measurements may not be affected by degenerative changes and may more accurately represent volumetric bone density in the lumbar spine. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT Metabolic bone disease is a public health concern affecting approximately 200million people worldwide. In 2010, USA prevalence of low bone mineral density (BMD) was 43.9% and osteoporosis 10.3% in adults >50years. Patients with bone disease may require intervention prior to elective spinal fusion procedures. BMD can be assessed radiographically using dual-energy X-ray absorptiometry (DXA) or quantitative computed tomography (QCT). QCT may have advantages over DXA for diagnosing low BMD in the lumbar spine. The American College of Radiology (ACR) defines the diagnostic criteria for the average QCT measurements at L1/L2 as follows: BMD>120 mg/cm3=normal, 80 mg/cm3.05). Pts >50years (n=248, 48.8% osteopenia, 17.7% osteoporosis) had significantly higher disease prevalence than <50yrs (n=48, 16.7% osteopenia, 0% osteoporosis), (P<.0001). Within a subgroup of 212 patients with no prior history of disease, 83 (39.2%) had osteopenia and 22 (10.4%) had osteoporosis. CONCLUSIONS In 296 consecutive patients undergoing lumbar spine fusion procedures, QCT analysis revealed 58.5% had pathologic bone density by ACR criteria. Patients >50years had substantially higher rates of low BMD compared to younger patients. Among patients with no history of low BMD, 49.6% met criteria for osteopenia or osteoporosis. Spine surgeons should be aware of the high prevalence of abnormal BMD in lumbar spine patients and the possibility that patients without a previous diagnosis may have osteopenia or osteoporosis. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To describe pre-treatment imaging features of pathologic fractures caused by primary bone tumors (PBTs) and metastatic bone tumors (MBTs) and determine if radiographic or cross-sectional features can differentiate the underlying pathologies associated with the fractures. Methods: Sixty-nine patients with a diagnosis of a pathologic fracture were enrolled. Biopsy established PBT as the cause of the pathologic fracture in 16 (23%) cases and MBT in 53 (77%) cases. The radiographs, computed tomography (CT) scans, and magnetic resonance imaging (MRI) scans of the subjects were retrospectively reviewed for the presence of multiple imaging features. Results: Compared to pathologic fractures caused by MBTs, the fractures caused by PBTs demonstrated a higher incidence of lytic bone cortex, mineralization and a soft-tissue mass on radiographs, mineralization and a soft-tissue mass on CT scans, and periosteal abnormality on MRI scans (P <0.01). These features also exhibited a high negative predictive value in supporting the diagnosis of an underlying PBT over MBT. Conclusion: Pathologic fractures caused by PBT and MBT may be differentiated by a few specific radiographic and CT imaging features, though MRI was poor for characterization of the underlying lesion. Such knowledge may assist radiologists in raising the possibility of a PBT as the cause of a pathologic fracture. [Copyright &y& Elsevier]