Area Of Vertebral Body Research Articles

Association of Outcomes of Spinal Cord Stimulation for Chronic Low Back Pain and Psoas Measurements Based on Size of Iliopsoas Muscles

IntroductionPatients experience variable long-term improvement in chronic back pain despite successful spinal cord stimulation (SCS) trials. Iliopsoas (IP) size has been shown to differ between patients with low back pain and healthy controls. In this study, we examine whether the IP muscle cross-sectional area (CSA) is associated with SCS outcomes. Materials and MethodsWe examined patients for whom we had lumbar MRIs 6.3 years prior to SCS and baseline and one-year outcome data. Percent change from baseline to one year was calculated for Numeric Rating Scale (NRS), Oswestry Disability Index (ODI), Beck Depression Inventory (BDI), Pain Catastrophizing Scale (PCS), and McGill Pain Questionnaire (MPQ). Correlations between IP muscle CSA, ratio of iliopsoas muscle size to the vertebral body area (P/VBA), and the ratio of iliopsoas muscle size to BMI (P/BMI) were examined. Sex differences were considered. ResultsA total of 73 subjects were included in this study, including 30 females and 43 males. Males had significantly larger IP (males 15.70 ± 0.58, females 9.72 ± 0.43; p < 0.001), P/VBA (males 1.00 ± 0.04, females 0.76 ± 0.03; p < 0.001), and P/BMI ratio (males 0.51 ± 0.02, females 0.32 ± 0.01; p < 0.001) than females. In females, P/VBA predicted NRS worst pain scores (β = 0.82, p = 0.004, r2 = 0.55) and BDI (β = 0.59, p = 0.02, r2 = 0.24). In males, P/BMI was a significant predictor of BDI outcome scores (β = 0.45, p = 0.03, r2 = 0.16). Males who had more muscle mass measured by iliopsoas size had more depression as measured using BDI (p = 0.03, r = 0.61). Females with less muscle mass measured by P/VBA also experienced more depression (p = 0.02, r = 0.74). ConclusionsOur study showed that psoas measurements correlated with various pain outcomes specifically. P/VBA was most predictive in females and P/BMI in males. Depression correlated with P/BMI, reinforcing the complex relationship between depression and constant chronic pain. Tertile analyses further showed a relationship between iliopsoas CSA and depression in males and females. We provide preliminary data of sex-specific psoas measurements as a risk factor for worse SCS outcomes.

Re-irradiation for intra-thoracic tumours and extra-thoracic breast cancer: dose accumulation, evaluation of efficacy and toxicity based on a literature review.

The improvement seen in the diagnostic procedures and treatment of thoracic tumours means that patients have an increased chance of longer overall survival. Nevertheless, we can still find those who have had a recurrence or developed a secondary cancer in the previously treated area. These patients require retreatment including re-irradiation. We have reviewed the published data on thoracic re-irradiation, which shows that some specific healthy tissues can tolerate a significant dose of irradiation and these patients benefit from aggressive treatment; however, there is a risk of damage to normal tissue under these circumstances. We analysed the literature data on re-irradiation in the areas of vertebral bodies, spinal cord, breast, lung and oesophagus. We evaluated the doses of primary and secondary radiotherapy, the treatment techniques, as well as the local control and median or overall survival in patients treated with re-radiation. The longest OS is reported in the case of re-irradiation after second breast-conserving therapy where the 5-year OS range is 81 to 100% and is shorter in patients with loco-reginal re-irradiation where the 5-y OS range is 18 to 60%. 2-year OS in patients re-irradiated for lung cancer and oesophagus cancer range from 13 to 74% and 18 to 42%, respectively. Majority grade ≥3 toxicity after second breast-conserving therapy was fibrosis up to 35%. For loco-regional breast cancer recurrences, early toxicity occurred in up to 33% of patients resulting in mostly desquamation, while late toxicity was recorded in up to 23% of patients and were mostly ulcerations. Early grade ≥3 lung toxicity developed in up to 39% of patients and up to 20% of Grade 5 hemoptysis. The most frequently observed early toxicity grade ≥3 in oesophageal cancer was oesophagitis recorded in up to 57% of patients, followed by hematological complications which was recorded in up to 50% of patients. The most common late complications included dysphagia, recorded in up to 16.7% of patients. We have shown that thoracic re-irradiation is feasible and effective in achieving local control in some patients. Re-irradiation should be performed with maximum accuracy and care using the best available treatment methods with a highly conformal, image-guided approach. Due to tremendous technological progress in the field of radiotherapy, we can deliver radiation precisely, shorten the overall treatment time and potentially reduce treatment-related toxicities.

EP.FRI.204 Does Sarcopenia Increase the Risk of Needing a Stoma During Emergency Laparotomy?

Abstract Aims Sarcopenia is a multisystem disorder which can be diagnosed clinically and radiologically. It is associated with impaired functional status and inferior perioperative outcomes, in particular increased mortality following emergency laparotomy. This study aimed to show whether sarcopenia, as defined by low psoas muscle area (PMA) on pre-operative CT, was associated with increased need for stoma formation. Methods A retrospective analysis of consecutive emergency general surgical laparotomies over a 3-year period. PMA was measured on a single pre-operative CT image at L3 and normalized to vertebral body area to create a psoas muscle index (PMI). New stoma formation and perioperative outcomes were recorded from patient records. Cases were split by the median value into high “non-sarcopenic” and low “sarcopenic” PMI groups. Results 299 patients underwent emergency laparotomy between 01/01/2016 and 31/12/2018. 46 patients (30.67%) in the low psoas index group required a stoma compared with 37 (24.83%) in the higher group (p = 0.159). Survival was inferior in the sarcopenic group with a mean survival of 42 months compared to 48 months in the non-sarcopenic group (p = 0.032). Median follow-up was 43 months. Patients in the sarcopenic group were significantly older (Mean age 68 compared to 54 in the non-sarcopenic group, p = &amp;lt;0.001) but there was no difference in other baseline variables. Conclusions Sarcopenia does not significantly increase the risk of requiring a stoma during emergency laparotomy but does reduce survival.

25. Total psoas area does not associate with perioperative mortality or morbidity after lumbar spine surgery

BACKGROUND CONTEXT In various surgical settings, single measures of frailty are increasingly used to guide patient selection and inform risk modification. Since a cardinal aspect of frailty is loss of functional capacity associated with loss of muscle mass, measures of sarcopenia have been looked to as indicators of frailty. Psoas muscle area (TPA) has emerged as a particularly practical and effective measure of sarcopenia. The present study aims to assess the utility of TPA as a predictor of perioperative morbidity and mortality. METHODS A retrospective review was conducted on 367 consecutive patients undergoing lumbar spinal surgery at our institution from January 2016 to February 2017. Demographic information was collected from review of the electronic medical record. Morphometric measurements including vertebral body area and right and left psoas muscle area were recorded by 2 independent readers at the mid-L3 level from MRI or CT within 1 year of index surgery. Outcomes included perioperative adverse events, rehospitalization within 90 days, and 90-day mortality. TPA and TPA indexed to vertebral area were calculated for all patients. RESULTS The overall rate of perioperative complication was 26%, rate of rehospitalization within 90 days was 15%, and 90-day mortality was 0.8%. Age, sex, history of hypertension, hyperlipidemia, diabetes, and former or current smoking were not associated with the incidence of adverse events, rehospitalization or death. Surgical characteristics including fusion type and number of vertebral levels treated were also not significantly associated with morbidity or mortality. Both TPA and TPA indexed to vertebral area did not associate with perioperative adverse events, rehospitalization, or 90-day mortality in both univariate regression and multivariate regression adjusting for age and for sex. Only a history of prior lumbar surgery was significantly associated with perioperative complication (OR 1.67, CI 1.04-2.68, p=0.03). CONCLUSIONS In an adult lumbar spine surgery population, morphometric measurements of TPA and TPA indexed to vertebral area were not associated with perioperative adverse event, rehospitalization, or mortality. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. In various surgical settings, single measures of frailty are increasingly used to guide patient selection and inform risk modification. Since a cardinal aspect of frailty is loss of functional capacity associated with loss of muscle mass, measures of sarcopenia have been looked to as indicators of frailty. Psoas muscle area (TPA) has emerged as a particularly practical and effective measure of sarcopenia. The present study aims to assess the utility of TPA as a predictor of perioperative morbidity and mortality. A retrospective review was conducted on 367 consecutive patients undergoing lumbar spinal surgery at our institution from January 2016 to February 2017. Demographic information was collected from review of the electronic medical record. Morphometric measurements including vertebral body area and right and left psoas muscle area were recorded by 2 independent readers at the mid-L3 level from MRI or CT within 1 year of index surgery. Outcomes included perioperative adverse events, rehospitalization within 90 days, and 90-day mortality. TPA and TPA indexed to vertebral area were calculated for all patients. The overall rate of perioperative complication was 26%, rate of rehospitalization within 90 days was 15%, and 90-day mortality was 0.8%. Age, sex, history of hypertension, hyperlipidemia, diabetes, and former or current smoking were not associated with the incidence of adverse events, rehospitalization or death. Surgical characteristics including fusion type and number of vertebral levels treated were also not significantly associated with morbidity or mortality. Both TPA and TPA indexed to vertebral area did not associate with perioperative adverse events, rehospitalization, or 90-day mortality in both univariate regression and multivariate regression adjusting for age and for sex. Only a history of prior lumbar surgery was significantly associated with perioperative complication (OR 1.67, CI 1.04-2.68, p=0.03). In an adult lumbar spine surgery population, morphometric measurements of TPA and TPA indexed to vertebral area were not associated with perioperative adverse event, rehospitalization, or mortality.

Sarcopenia estimation using psoas major enhances P-POSSUM mortality prediction in older patients undergoing emergency laparotomy: cross-sectional study.

Emergency laparotomy is a considerable component of a colorectal surgeon's workload and conveys substantial morbidity and mortality, particularly in older patients. Frailty is associated with poorer surgical outcomes. Frailty and sarcopenia assessment using Computed Tomography (CT) calculation of psoas major area predicts outcomes in elective and emergency surgery. Current risk predictors do not incorporate frailty metrics. We investigated whether sarcopenia measurement enhanced mortality prediction in over-65s who underwent emergency laparotomy and emergency colorectal resection. An analysis of data collected prospectively during the National Emergency Laparotomy Audit (NELA) was conducted. Psoas major (PM) cross-sectional area was measured at the L3 level and a ratio of PM to L3 vertebral body area (PML3) was calculated. Outcome measures included inpatient, 30-day and 90-day mortality. Statistical analysis was conducted using Mann-Whitney, Chi-squared and receiver operating characteristics (ROC). Logistic regression was conducted using P-POSSUM variables with and without the addition of PML3. Nine-hundred and forty-four over-65s underwent emergency laparotomy from three United Kingdom hospitals were included. Median age was 76years (IQR 70-82years). Inpatient mortality was 21.9%, 30-day mortality was 16.3% and 90-day mortality was 20.7%. PML3 less than 0.39 for males and 0.31 for females indicated significantly worse outcomes (inpatient mortality 68% vs 5.6%, 30-day mortality 50.6% vs 4.0%,90-day mortality 64% vs 5.2%, p < 0.0001). PML3 was independently associated with mortality in multivariate analysis (p < 0.0001). Addition of PML3 to P-POSSUM variables improved area under the curve (AUC) on ROC analysis for inpatient mortality (P-POSSUM:0.78 vs P-POSSUM + PML3:0.917), 30-day mortality(P-POSSUM:0.802 vs P-POSSUM + PML3: 0.91) and 90-day mortality (P-POSSUM:0.79 vs P-POSSUM + PML3: 0.91). PML3 is an accurate predictor of mortality in over-65s undergoing emergency laparotomy. Addition of PML3 to POSSUM appears to improve mortality risk prediction.

Sex Estimation of Typical Adult Vertebrae Morphology in Central China Based on CT Technique

Objective The morphological data of the second thoracic vertebra and the third lumbar vertebra were measured by computerized tomography （CT）. The sex differences were analyzed and the discrimination equation was obtained. Methods The data of 274 adults （203 cases from experimental group and 69 cases from validation group） from central China were collected. Four linear data （maximum transverse length of vertebral body, maximum longitudinal length of vertebral body, maximum transverse length of vertebral foramen, maximum longitudinal length of vertebral foramen）, one angle data （angle between spinous processes） and two area （vertebral foramen area, total cross-sectional area of vertebral body） data of the second thoracic vertebra and the third lumbar vertebra were collected, respectively. Then three ratios ［maximum transverse length/ maximum longitudinal length of vertebral body, maximum transverse length/ maximum longitudinal length of vertebral foramen, vertebral foramen area/ （total cross-sectional area of vertebral body-vertebral foramen area）］ and one angle （angle between spinous processes） were obtained. The discriminant equation was established for sexual discriminant analysis. Results The morphology of the second thoracic vertebra and the third lumbar vertebra was related with gender. Four single index discriminant formulae and eleven multi-index discriminant formulae were established. The 69 validation group samples were substituted into the formula for testing, and the maximum discriminant accuracy rate of the single-index discriminant formula was 75%. The maximum discriminant accuracy rate of multi-index discriminant formula was 83%. Conclusion It is feasible to conduct individual sex analysis by the morphological indexes of second thoracic vertebra and the third lumbar vertebra. The indexes have important application values in practice.

Carbon fiber-reinforced pedicle screws reduce artifacts in magnetic resonance imaging of patients with lumbar spondylodesis

The study investigated whether the use of carbon fiber-reinforced PEEK screw material (CF-PEEK) can reduce magnetic resonance imaging (MRI) artifact formation. Two consecutive groups of patients were treated for degenerative spinal disorders of the lumbar spine with dorsal transpedicular spinal fusion. The first group (n = 27) received titanium pedicle screws. The second group (n = 20) received CF-PEEK screws. All patients underwent an MRI assessment within the first four postoperative weeks. For each operated segment, the surface of the artifact-free vertebral body area was calculated as percentage of the total vertebral body. For each implanted segment, the assessability of the spinal canal, the neuroforamina, and the pedicle screws, as well as the surrounding bony and soft-tissue structures was graded from 1 to 5. A mean artifact-free vertebral body area of 48.3 ± 5.0% was found in the in the titanium group and of 67.1 ± 5.6% in the CF-PEEK group (p ≤ 0.01). Assessability of the lumbar spine was significantly improved for CF-PEEK screws (p ≤ 0.01) for all measurements. CF-PEEK pedicle screws exhibit smaller artifact areas on vertebral body surfaces and their surrounding tissues, which improves the radiographic assessability. Hence, CF-PEEK may provide a diagnostic benefit.

The Effect of Compression Applied Through Constrained Lateral Eccentricity on the Failure Mechanics and Flexibility of the Human Cervical Spine.

In contrast to sagittal plane spine biomechanics, little is known about the response of the cervical spine to axial compression with lateral eccentricity of the applied force. This study evaluated the effect of lateral eccentricity on the kinetics, kinematics, canal occlusion, injuries, and flexibility of the cervical spine in translationally constrained axial impacts. Eighteen functional spinal units were subjected to flexibility tests before and after an impact. Impact axial compression was applied at one of three lateral eccentricity levels based on percentage of vertebral body width (low = 5%, medium = 50%, high = 150%). Injuries were graded by dissection. Correlations between intrinsic specimen properties and injury scores were examined for each eccentricity group. Low lateral force eccentricity produced predominantly bone injuries, clinically recognized as compression injuries, while medium and high eccentricity produced mostly contralateral ligament and/or disc injuries, an asymmetric pattern typical of lateral loading. Mean compression force at injury decreased with increasing lateral eccentricity (low = 3098 N, medium = 2337 N, and high = 683 N). Mean ipsilateral bending moments at injury were higher at medium (28.3 N·m) and high (22.9 N·m) eccentricity compared to low eccentricity specimens (0.1 N·m), p < 0.05. Ipsilateral bony injury was related to vertebral body area (VBA) (r = -0.974, p = 0.001) and disc degeneration (r = 0.851, p = 0.032) at medium eccentricity. Facet degeneration was correlated with central bony injury at high eccentricity (r = 0.834, p = 0.036). These results deepen cervical spine biomechanics knowledge in circumstances with coronal plane loads.

Abstract A106: Key differences in muscular index and tumor burden reveal unique biology in ethnically diverse patients with pancreatic cancer

Abstract Introduction: The racial disparities in pancreatic cancer (PC), while not fully appreciated, are recognized amongst PC experts. African Americans are diagnosed more frequently, present with more advanced disease, and suffer from higher mortality rates than White patients. Overall, cancer cachexia, or cancer-associated muscle wasting, greatly contributes to both morbidity and mortality. While cachexia is experienced by more than 80% of patients with PC, PC-induced cachexia and how it contributes to a disparity amongst African Americans is under investigation. African Americans with PC present with increased muscle wasting (-29%) than their White counterparts with PC (-14%). Therefore, we hypothesize that an established radiographically obtained muscular index (a psoas index) uniquely corresponds to increased disease burden in African Americans with early-stage disease. Methods: African American and White patients with pancreatic ductal adenocarcinoma who underwent surgery at our institution between 2010 and 2017 were included in this retrospective study. A muscular index for each patient was measured from preoperative CT scans by dividing the average area of the psoas muscles at L3 by the L3 vertebral body area to normalize the measurement for patient size. Supplementary relevant clinical, pathologic, and laboratory values were used for comparison. Results: 15 African American and 15 White surgical patients with PC were matched by gender and history of neoadjuvant therapy; age was similar in both groups (65.7 vs. 64.3, p=0.6566). Gross tumor size was similar in African Americans and Whites (2.553 vs. 3.093, p=0.3097). Tumor size, however, inversely correlated to psoas index in African Americans (r=0.4330, p=0.0077), but not in Whites (r=0.002525, p=0.8588). African Americans with lower psoas indices generally had larger tumors. Similar to tumor size, the positive lymph node ratio (LNR) inversely correlated to psoas index in African Americans (r=0.3930, p=0.0124), but not in Whites (r=0.08673, p=0.2867). LNR was significantly greater in Whites than African Americans (0.0627 vs. 0.2253, p=0.0020). Overall survival was, however, similar in both groups (15.8 vs. 14.3, p=0.7117). Conclusion: A decreased psoas index in African American patients is associated with greater tumor size and an increased positive LNR. Notably, the most powerful outcome variable (LNR) did not correlate with psoas index in White patients even in the presence of increased nodal metastases. Most surprisingly, overall survival was similar in both patient groups. This suggests that a limited tumor burden does not provide a survival benefit for African Americans. We conclude that recognizing biologic variance among patients with ethnic diversity will allow better strategies to characterize metabolism, tumor microenvironment, and muscle architecture in PC. Together this will lead to improved overall survival. Citation Format: Miles E. Cameron, Patrick W. Underwood, Michael H. Gerber, Steven J. Hughes, Andrew R. Judge, Jennifer B. Permuth, Jose G. Trevino. Key differences in muscular index and tumor burden reveal unique biology in ethnically diverse patients with pancreatic cancer [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr A106.

An Objective and Reliable Method for Identifying Sarcopenia in Lumbar Spine Surgery Patients: Using Morphometric Measurements on Computed Tomography Imaging.

Study DesignA retrospective observational study.PurposeEstablish a quantifiable and reproducible measure of sarcopenia in patients undergoing lumbar spine surgery based on morphometric measurements from readily available preoperative computed tomography (CT) imaging.Overview of LiteratureSarcopenia—the loss of skeletal muscle mass—has been linked with poor outcomes in several surgical disciplines; however, a reliable and quantifiable measure of sarcopenia for future assessment of outcomes in spinal surgery patients has not been established.MethodsA cohort of 90 lumbar spine fusion patients were compared with 295 young, healthy patients obtained from a trauma da¬tabase. Cross-sectional vertebral body (VB) area, as well as the areas of the psoas and paravertebral muscles at mid-point of pedicles at L3 and L4 for both cohorts, was measured using axial CT imaging. Total muscle area-to-VB area ratio was calculated along with intraclass correlation coefficients for interobserver and intraobserver reliability. Finally, T-scores were calculated to help identify those patients with considerably diminished muscle-to-VB area ratios.ResultsBoth muscle mass and VB areas were considerably larger in males compared with those in females, and the ratio of these two measures was not enough to account for large differences. Thus, a gender-based comparison was made between spine patients and healthy control patients to establish T-scores that would help identify those patients with sarcopenia. The ratio for paravertebral muscle area-to-VB area at the L4 level was the only measure with good interobserver reliability, whereas the other three of the four ratios were moderate. All measurements had excellent correlations for intraobserver reliability.ConclusionsWe postulate that a patient with a T-score <−1 for total paravertebral muscle area-to-VB area ratio at the L4 level is the most reliable method of all our measurements that can be used to diagnose a patient undergoing lumbar spine surgery with sarcopenia.

Effect of Sarcopenia on Mortality after Percutaneous Vertebral Augmentation Treatment for Osteoporotic Vertebral Compression Fractures in Elderly Patients: A Retrospective Cohort Study

The aim to evaluate central sarcopenia, as measured by psoas cross-sectional area on admission imaging, is associated with outcomes in patients with vertebral compression fractures (VCFs) treated with percutaneous vertebral augmentation treatment. We evaluated the records of patients aged >60 years treated with vertebroplasty or kyphoplasty between 2009 and 2018 for osteoporotic VCFs. The Social Security Death Index was used to determine death. We used the psoas:lumbar vertebral index (PLVI), calculated using the cross-sectional area of the L4 vertebral body and the left and right psoas muscles, to assess for sarcopenia. A multivariate Cox algorithm was applied to recognize factors independently associated with survival. A total of 103 patients were included with an average age of 72.3 years. During the study period, 22 (21.4%) patients were deceased, whereas 81 (78.6%) were alive. The survival rates at 1 month, 6 months, and 1 year after surgery were 99%, 94.1%, and 88.4%, respectively. PLVI measurements ranged from 0.24-1.19 with a mean of 0.59 ± 0.17 and a median of 0.603. A total of 51 patients with a median value of 0.603 were defined as low PLVI group, and 52 patients with a median value of ≥0.603 were defined as the high PLVI group. PLVI was significantly low in patients who died. Age, American Society of Anesthesiologists score, and PLVI value were independently associated with a poor overall survival. There is a significant correlation between sarcopenia and postoperative mortality after vertebral augmentation procedure in patients with VCFs.

Human lumbar spinal column injury criteria from vertical loading at the base: Applications to military environments

The objective of this study was to determine force-based lumbar spine injury criteria due to vertical impact using Post Mortem Human Surrogate (PMHS) experiments. Mounted personnel in military vehicles sustain loads from the pelvis in combat events such as underbody blast loadings. Forty-three post mortem human subject thoracolumbar spinal columns were obtained, screened for pre-existing trauma, bone mineral densities (BMDs) were determined, pre-test radiological images were taken, fixed at the ends in polymethylmethacrylate, load cells were attached to the ends of the fixation, positioned on custom vertical accelerator device based on a military-seating posture, and impacted at the base. Posttest images were obtained, and gross dissection was done to confirm injuries, classified into single and multilevel groups, groups A and B. Axial and resultant forces at the thoracolumbar (proximal) and lumbosacral (distal) joints were used as response variables to develop lumbar spine injury risk curves using parametric survival analysis. The Brier score metric was used to rank the variables. Age, BMD, column length, and vertebral body and intervertebral disc areas were used as covariates. The optimal metric describing the underlying response to injury was the distal resultant force for group A and proximal axial force for group B specimens. Force-BMD for group A and force-body area for group B were the best combinations. The IRCs with ±95% confidence intervals and quality of risk curves are given in the paper, and they serve as lumbar spine injury criteria. The present human cadaver Injury Risk Curves (IRCs) can be used to conduct matched pair tests to obtain dummy-based injury assessment risk curves/values to predict injury. The present IRCs can be used in human body finite element models. The relationship between covariates and primary forces presented in this study contribute to a better understanding of the role of demographic, geometric, and material factors to impact acceleration loading.

Is there cervical spine muscle weakness in patients with Hirayama disease? A morphological study about cross-sectional areas of muscles on MRI.

Patients with Hirayama disease (HD) present with a larger range of neck flexion and show signs of cervical spine instability. Cervical spine stability largely relies on cervical spine muscles. The purpose of this study was to compare the cross-sectional areas (CSAs) of cervical spine muscles between patients with HD and healthy controls, providing some insights into whether there is cervical spine muscle weakness and incongruence in HD patients. In this retrospective study, cervical spine muscles CSAs of 44 HD patients, as well as that of 44 age- and sex-matched healthy counterparts, were measured on the T2-weighted axial MR images. The ratios of cervical spine muscles CSA to the corresponding vertebral body areas, defined as R-CSAs, and the flexor/extensor CSA ratios were computed and compared between two groups. Compared with healthy counterparts, R-CSAs of total cervical spine muscles, total extensors, superficial extensors, and deep flexors were significantly lower in HD patients. HD patients also demonstrated a significantly greater superficial flexor/superficial extensor CSA ratio than the healthy counterparts, indicating a mismatch between superficial flexors CSA and superficial extensors CSA in HD patients. In this pioneering study, HD patients had decreased size in most cervical spine muscles and a mismatch between CSAs of superficial flexor and that of superficial extensors. These results indicate generalized weakness and incongruence of cervical spine muscles, which may predispose cervical spine of HD patients to a less stable situation. These slides can be retrieved under Electronic Supplementary Material.

Validation of two-dimensional vertebral body parameters in estimating patient height in elderly patients.

Standardised comparison of abdominal muscle and adipose tissue is often utilised in morphometric clinical research. Whilst measurements are traditionally standardised against the patient's height, this may not be always practically feasible. The aim of this study was to investigate the relationship between measurements of the vertebral body and patient height. We analysed cross-sectional CT scans. Measurements of the vertebral body area (VBA), anteroposterior vertebral body diameter (APVBD) and lateral vertebral body diameter (LVBD) were made by two independent investigators by manual tracing. Patients were randomly divided into two groups: Group 1 standardisation and Group 2 validation. We compared height and vertebral body parameters from patients in Group 1 and mathematically modelled this relationship. We then utilised the model to predict the height of patients in Group 2 and compared this with their actual height. Observer variability was assessed using Bland-Altman plots and t-tests of differences. CT scans from 382 patients were analysed. No significant intraobserver or interobserver differences were apparent when measuring vertebral body parameters. We describe models which enable the prediction of the patients' height using the measured VBA, APVBD and LVBD. No significant differences were observed between the patients predicted and actual heights in the validation group. We demonstrate an important relationship between measurements of the patient's height and the vertebral body. This can be utilised in future research when the patient's height has not been measured. In the absence of the patient's height, we demonstrate that two-dimensional vertebral body parameters may be reliably used to standardise morphometric measurements.

Abstract 4004: Unique patient signatures underlie health disparities in ethnically diverse patients with pancreatic cancer

Abstract Introduction: Health disparities in pancreatic cancer (PC) exist but how the underlying biology contributes to this is poorly described. Black Americans have a higher prevalence, present with more advanced disease, and suffer from higher mortality rates than other ethnic groups. Cancer cachexia, or cancer-associated muscle wasting, affects more than 80% of patients with PC. Unique muscular characteristics exist in different ethnic groups which might be contributing to pancreatic cancer health disparities. We hypothesize that Black patients with PC have a distinct muscular profile and are more affected by cancer cachexia than Whites and that unique genomic variations might contribute to this phenomenon in PC tumors between Black and White patients. Methods: Black (including African Americans and Afro-Caribbeans) and non-Hispanic White surgically resected patients with PC between 2010 and 2017 were case matched by age, gender, and tumor grade. Muscular indices were measured from CT scans by dividing the area of the psoas muscles by the L3 vertebral body area to normalize for patient size. Whole-exome sequencing was performed on DNA from tumor and adjacent benign parenchyma. Results: Healthy Blacks have a greater psoas index than Whites (0.8995 vs. 0.6988, p=0.004). When comparing patients with PC, Blacks and Whites were found to have similar psoas indices. Black patients had a greater percent decrease in psoas index than White patients (-25.29% vs. -12.37%, p=0.04). Tumor size inversely correlated to psoas index in Blacks (r=0.4330, p=0.007), but not in Whites (r=0.0025, p=0.9). Similar to tumor size, the positive lymph node ratio (LNR) inversely correlated to psoas index in Black patients (r=0.3930, p=0.01), but not in White patients (r=0.0867, p=0.2). LNR was significantly greater in Whites than Blacks (0.0627 vs. 0.2253, p=0.002), but overall survival was similar in both groups (15.8 vs. 14.3, p=0.7). In whole-exome sequencing, there were 22 mutations, of which several harbored implications in chemoresistance (ABCF1, ANAPC1), metastasis (CYP2A7, CYP21A2), and pathways of tumorigenesis (PHACTR4, PPP1R12B), and had 100% penetrance in Blacks but not in Whites. Seven mutations were present only in tumors of Whites but not Blacks. Conclusion: Black Americans with PC suffer more muscle loss in the early stages of disease than Whites. A decreased psoas index in Black patients is associated with worse prognostic factors. In our genetic analysis, we identified 27 novel mutations not before reported in the literature. We conclude that recognizing biological variance in patients may underlie health disparities and allow investigations toward defining specific targets in a diverse group of patients with PC. Citation Format: Miles E. Cameron, Patrick W. Underwood, Jinping Lai, Jennifer B. Permuth, Andrew R. Judge, Jose G. Trevino. Unique patient signatures underlie health disparities in ethnically diverse patients with pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4004.

T-score differences and nonprogression in lumbar vertebrae as predictors of vertebral fractures.

In case of a vertebral fracture, the area of the vertebrae decreases with a concomitant increase in BMD, as assessed by a DXA scanning. Furthermore, a vertebral fracture may disrupt the normal increase in vertebral body area from L1 to L4 (nonprogression). We aimed to examine associations between T-score difference and nonprogression of vertebral area and vertebral fractures. We identified 100 patients with 1 or more fractures in L1-L4 and 106 patients without fractures. All patients had undergone a DXA scan and a lumbar spine X-ray. In fracture patients, we recorded T-score difference between the fractured vertebra and the adjacent vertebra, and whether the fractured vertebra was smaller than the one above (nonprogression). In nonfracture patients, the greatest positive T-score difference was recorded, and nonprogression was present if vertebral area did not increase successively from L1 to L4. With a T-score difference ≥1SD odds ratio for fracture was 1.30 (0.74-2.29). Sensitivity and specificity were 0.40 and 0.66, respectively. With T-score difference ≥1.5SD, odds ratio for fracture was 2.26 (1.08-4.73). Sensitivity and specificity were 0.24 and 0.88, respectively. Nonprogression was very common in the no-fracture group (38%), while only 23% of X-ray verified fractures had nonprogression. A randomly found T-score difference ≥1.5SD between adjacent vertebrae on a DXA scan is associated with a small increased risk of compression fracture. Nonprogression is very common in patients without fractures.

Response of the Axial Skeleton to Bipedal Loading Behaviors in an Experimental Animal Model.

Many derived aspects of modern human axial skeletal morphology reflect our reliance on obligate bipedal locomotion. Insight into the adaptive significance of features, particularly in the spine, has been gained through experimental studies that induce bipedal standing or walking in quadrupedal mammals. Using an experimental animal model (Rattus norvegicus), the present study builds on earlier work by incorporating additional metrics of the cranium, employing quantitative methods established in the paleoanthropological literature, and exploring how variation in mechanical loading regimes impacts axial anatomy. Rats were assigned to one of five experimental groups, including "fully loaded bipedal walking," "partially loaded bipedal walking," "standing bipedally," "quadrupedal walking," and "no exercise control," and engaged in the behavior over 12-weeks. From μCT data obtained at the beginning and end of the experiment, we measured foramen magnum position and orientation, lumbar vertebral body wedging, cranial surface area of the lumbar and first sacral vertebral bodies, and sacral mediolateral width. Results demonstrate that bipedal rodents generally have more anteriorly positioned foramina magna, more dorsally wedged lumbar vertebrae, greater articular surface areas of lumbar and first sacral vertebral bodies, and sacra that exhibit greater mediolateral widths, compared to quadrupedal rodents. We further document variation among bipedal loading behavior groups (e.g., bipedal standing vs. walking). Our experimental animal model reveals how loading behaviors and adaptations may be specifically linked, and implicates a potential role for developmental plasticity in the evolutionary acquisition of bipedal adaptations in the hominin lineage. Anat Rec, 2018. © 2018 American Association for Anatomy.

Cervical Intervertebral Disk to Vertebral Body Ratios of Different Dog Breeds Based on Sagittal Magnetic Resonance Imaging.

Objective: To establish sagittal area and length reference values and ratios between apparently normal canine cervical vertebrae and intervertebral disks using magnetic resonance imaging.Sample: Retrospective evaluation of cervical vertebral column magnetic resonance imaging studies of 44 dogs representing 5 different breeds (Labrador Retriever, n = 10; French Bulldog, n = 10; Great Dane, n = 9; Chihuahua, n = 10; Dachshund, n = 5).Procedures: Mid-sagittal measurements of vertebral body and disk areas were obtained from C3 through C7 vertebrae and C2/C3 through C6/C7 intervertebral disks. Disk to vertebra area ratios were calculated and compared among dog breeds. Additionally, sagittal vertebral body and disk length measurements were obtained and disk to vertebra length ratios calculated. Inter and intra observer variability was assessed.Results: There were significant differences for disk to vertebral body area and length ratios between evaluated dog breeds and cervical vertebral locations (p < 0.001). Mean area ratio of Chihuahuas was significantly larger than all other breeds, while results from Dachshunds were only significantly different than Chihuahuas and Labrador Retrievers. Mean area ratios were statistically different between the cranial and caudal cervical vertebral locations. Regarding length ratios, results from Chihuahuas were significantly different than all breeds except Dachshunds. Mean length ratios were statistically different between all cervical locations, except C2/C3 compared to C3/C4. Intra- and interobserver variability was very good to excellent.Conclusion and Clinical Relevance: There are significant differences in area and length ratios between dog breeds. Differences also exist in area and length ratios between the cranial and caudal cervical vertebral column. These differences may play a role in the development of vertebral column diseases including intervertebral disk disease.

Sarcopenia Is Predictive of 1-Year Mortality After Acetabular Fractures in Elderly Patients.

To determine whether sarcopenia is an independent predictor of mortality in geriatric acetabular fractures. Retrospective cohort. American College of Surgeons Level I trauma center. One hundred and forty-six patients over the age 60 with acetabular fractures treated at our institution over a 12-year period. The primary outcome was 1-year mortality, collected using the Social Security Death Index. We used the psoas:lumbar vertebral index (PLVI), calculated using the cross-sectional area of the L4 vertebral body and the left and right psoas muscles, to assess for sarcopenia. Using a multivariate logistic regression model, we found that low PLVI was associated with increased 1-year mortality (P = 0.046) when controlling for age, gender, Charlson Comorbidity Index, Injury Severity Score (ISS), smoking status, and associated pelvic ring injury. Increasing age and ISS also showed a relationship with 1-year mortality in this cohort (P < 0.001, P < 0.001, respectively). We defined sarcopenia as those patients in the lowest quartile of PLVI. The mortality rate of this cohort was 32.4%, compared with 11.0% in patients without sarcopenia (odds ratio 4.04; 95% confidence interval 1.62-10.1). Age >75 years, ISS >14, and sarcopenia had 1-year mortality rates of 37.1%, 30.9%, and 32.4%, respectively. In patients with all 3 factors, the mortality rate was 90%. Sarcopenia is an independent risk factor for 1-year mortality in elderly patients with acetabular fractures. This study highlights the importance of objective measures to assess frailty in elderly patients who have sustained fractures about the hip and pelvis. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Applications of one-stage total spondylectomy by anterior and posterior approaches for solitary plasmacytoma of cervical spine

To investigate the feasibility of one-stage total spondylectomy by anterior and posterior approaches for treating solitary plasmacytoma (SP) of cervical spine. Between June 2000 and March 2015, the clinical data, diagnosis, and treatment of 12 patients with SP of cervical spine were retrospectively analyzed. There were 8 males and 4 females, with a mean age of 46 years (range, 28-74 years). The mean disease duration was 8.4 months (range, 3-15 months). There were 2 cases in C 2 segment, 4 cases in C 3, 2 cases in C 4, 1 recurrent case in C 5, C 6, and 3 cases in C 7. According to WBB (Weinstein-Boriani-Biagini) surgical staging system, the tumor mainly occupied the vertebral body areas and expanded outside to 4 or 9 radiating zone in 8 cases, expanded both outsides to 4 or 9 radiating zones in 4 cases; 7 cases of them affected A to D layers, other 5 cases affected B to D layers. Preoperative Frankel system showed grade B in 1 case, grade C in 6 cases, and grade D in 5 cases. One vertebra segment was involved in 11 cases, and 2 vertebra segments were involved in 1 case. The unilateral vertebral artery was involved in 4 cases and bilateral vertebral artery in 1 case. One-stage total spondylectomy by anterior and posterior approaches for SP of cervical spine was applied in all patients, which all received adjuvant radiotherapy postoperatively. The operation time, intraoperative blood loss, complications, Frankel system, and visual analogue scale (VAS) score were recorded and analyzed. The operation time was 6.8-9.3 hours (mean, 7.2 hours), and the intraoperative blood loss was 1 100-2 600 mL (mean, 1 600 mL). Esophageal leakage occurred in 1 patient with C 5, C 6 recurrent SP at 1 week after operation and 1 case presented with fat liquefaction of wound, who were cured by symptomatic treatment. Other patients showed no neurological deficit, major vascular injury (especially vertebral artery), phrenic nerve injury, superior laryngeal nerve injury, laryngeal nerve injury, respiratory failure, or other complications. All the 12 patients were followed up 27-98 months (mean, 58 months). The symptoms of spinal cord compression disappeared or improved after operation. At last follow-up, the nerve function was recovered to Frankel grade E in all patients; the VAS score decrease to 1.1±0.7, showing significant difference when compared with preoperative value (6.7±2.7) ( t=2.485, P=0.014). Two patients had local recurrence at 29 months and 37 months after operation respectively, which were treated with adjuvant chemotherapy. One of them finally progressed to multiple myeloma and died of multiple organ failure after 43 months, the other one survived with residual tumor. One case presented with internal fixator loosening and breaking at 4 years after operation, who was performed revision surgery. The other patients had no tumor recurrence or malignant change during the follow-up, no complication such as internal fixator loosening or breaking occurred. For patients with SP of cervical spine, surgical intervention is an acceptable treatment option. One-stage total spondylectomy by anterior and posterior approaches can decline the local recurrence and relieve the symptoms of spinal cord compression, so as to improve patients' life quality. However, patients with progression to multiple myeloma should be treated with individualized therapeutic regimen, and the prognosis may be poor.