Paraspinal Muscle Area Research Articles

Yttrium-90 radioembolization for hepatocellular carcinoma: Outcome prediction with MRI derived fat-free muscle area

PurposeSarcopenia is associated with adverse outcomes in several gastrointestinal malignancies and liver cirrhosis. We aimed to study the utility of magnetic resonance imaging (MRI) derived fat-free muscle area (FFMA) to predict clinical outcome in patients receiving yttrium-90 radioembolization (RE) for treatment of hepatocellular carcinoma (HCC). MethodsFifty-eight patients with unresectable HCC and pre-interventional liver MRI undergoing salvage RE were retrospectively evaluated. Using axial T2-weighted turbo spin echo sequences, FFMA was calculated by subtraction of the intramuscular adipose tissue area from the total cross-sectional area of paraspinal skeletal muscles at the superior mesenteric artery level. FFMA values lower than 3582 mm2 in male and 2301 mm2 in female patients were defined as low FFMA. Main outcomes were progression-free survival (PFS) and overall survival (OS). For outcome analysis, the Kaplan-Meier method with log rank test and multivariate cox regression analysis were used. ResultsMean time from pre-interventional MRI to RE was 27 ± 20 days. Median OS and PFS after RE were 250 (range: 21–1230 days) and 156 days (range: 21–674 days), respectively. Patients with low FFMA showed significantly reduced OS (197 vs. 294 days, P = 0.024) and tended to have shortened PFS (109 vs. 185 days, P = 0.068). Low FFMA (HR 2.675; P = 0.011), estimated liver tumor burden (HR 4.058; P = 0.001), and Eastern Cooperative Oncology Group (ECOG) performance status (1.763; P = 0.009) were independent predictors of OS on multivariate analysis. ConclusionsFFMA as a measure of sarcopenia predicts OS and might represent a promising new biomarker for survival prognosis in patients undergoing RE for treatment of unresectable HCC.

Continued muscle loss increases mortality in cirrhosis: Impact of aetiology of liver disease

Sarcopenia or skeletal muscle loss adversely affects outcomes in cirrhosis. The impact of aetiology of liver disease on the severity or the rate of muscle loss is not known. Consecutive, well-characterized adult patients with cirrhosis due to viral hepatitis (VH), alcoholic liver disease (ALD) or non-alcoholic fatty liver disease (NAFLD) and non-diseased controls with at least two temporally distinct abdominal CT (computed tomography) scans were evaluated. Psoas, paraspinal and abdominal wall muscle areas at the L3 vertebra level were quantified on the CT scans. Standardized rate of change in muscle area was expressed as change in area/100days. Univariate and multivariable analyses were performed to identify contributors to rate of muscle loss and survival. Among 83 cirrhotics (NAFLD n=26, ALD n=39, VH n=18), there were 20 (24.1%) deaths over 62.7±41.3months. The mean percentage change in psoas area was -0.03±0.05/100d in controls and -3.52±0.45/100d in cirrhosis (P<.001). The mean percentage change in psoas area was -1.72±0.27/100d in NAFLD, -5.28±0.86/100d in ALD and -2.29±0.28/100d in VH. Among cirrhotics, patients with ALD had the lowest initial muscle area and most rapid rate of reduction in muscle area. Aetiology of liver disease, model for end-stage liver disease (MELD) and the rate of loss of muscle area were independent risk factors for survival. Aetiology of liver disease is an independent risk factor for sarcopenia with the greatest rate of muscle loss noted in ALD. Survival in cirrhosis was dependent on initial muscle mass, rate of muscle loss and MELD score.

Clinical Significance of Paraspinal Muscle Parameters as a prognostic factor for survival in Gastric Cancer Patients who underwent Curative Surgical Resection.

Background: The quantitative and qualitative skeletal muscle parameters have been proposed to predict the outcome of patients with gastric cancer. However, the evidence for their association with long-term survival is still conflicting. This study aimed to investigate the effect of paraspinal muscle parameters on overall survival (OS) and disease-free survival (DFS) in patients with gastric cancer who underwent curative resection.Methods: Patients with stages I or II gastric cancer who underwent curative resection between October 2006 and June 2016 were identified from electrical medical records. Paraspinal muscle area and attenuation were measured at the level of the third lumbar vertebra using computerized tomography images. For the analysis of OS and DFS, proportional hazards model was used, incorporating demographic, pathologic, laboratory, and radiologic variables.Results: This study enrolled 296 patients (192 men and 104 women). In the multivariate proportional hazards model, total gastrectomy (hazard ratio [HR], 2.65; 95% Confidence interval [CI], 1.36-5.19; p = 0.0044), neutrophil-lymphocyte ratio (NLR) (HR, 1.27; 95% CI, 1.06-1.51; p = 0.0081), serum albumin level (HR, 0.16; 95% CI, 0.07-0.39; p < 0.0001), paraspinal muscle area adjusted for body surface area (PMABSA) (HR, 3.06; 95% CI, 1.65-5.67; p = 0.0004), and mean attenuation in paraspinal muscle (PMMA) (HR, 3.38; 95% CI, 1.75-6.53; p = 0.0003) were prognostic factors for OS. Similarly, total gastrectomy (HR, 2.11; 95% CI, 1.10-4.06; p = 0.0243), NLR (HR, 1.25; 95% CI, 1.06-1.48; p = 0.0071), serum albumin level (HR, 0.22; 95% CI, 0.10-0.51; p = 0.0035), PMABSA (HR, 2.42; 95% CI, 1.34-4.37; p = 0.0035), and PMMA (HR, 3.19; 95% CI, 1.71-5.93; p = 0.0003) were prognostic factors for DFS.Conclusions: The pretreatment paraspinal muscle parameters such as PMABSA and PMMA along with total gastrectomy, NLR, and serum albumin level could predict OS and DFS in patients with stages I or II gastric cancer who underwent curative surgical resection. Because PMABSA and PMMA are newly characterized parameters in gastric cancer, the relationship with the survival of these parameters requires further validation in further studies before they are subjected to clinical applications.

Association of MRI-defined lumbar paraspinal muscle mass and slip percentage in degenerative and isthmic spondylolisthesis: A multicenter, retrospective, observational study.

The objective of this study is to investigate the role of paraspinal muscles in the progression of different types of spondylolisthesis by examining the correlation between cross-sectional area (CSA) of lumbar paraspinal muscle and slip percentage (SP) in degenerative spondylolisthesis and isthmic spondylolisthesis.A multicenter retrospective analysis was carried out including 219 subjects diagnosed with lumbar spondylolisthesis. Using T2-weighted axial magnetic resonance imgaging, CSAs of the psoas major (PM), multifidus (MU), and erector spinae were measured and divided by L5 vertebral body (VB) CSA. SP was measured using sagittal T2-weighted images. Correlations between muscle CSA ratio and SP were calculated in each group. Regression analysis was performed to predict the influence of each muscle CSA/VB CSA ratio on SP.No significant correlation was found in the degenerative spondylolisthesis group between any of the muscle CSA ratios and SP. Both PM/VB ratio (r = −0.24, P = .021) and MU/VB ratio (r = −0.26, P = .012) were negatively correlated with SP in the isthmic spondylolisthesis group. MU had more influence on SP than PM in the isthmic spondylolisthesis group (regression coefficient MU/VB: −8.08, PM/VB: −4.34).Both PM and MU muscle CSA ratios were negatively correlated with SP in the isthmic group. MU had more influence on SP than PM. No muscles had any correlations with SP in the degenerative group. This discrepancy between the two groups suggests that exercise programs or interventions regarding the segmental stability of isthmic spondylolisthesis and degenerative spondylolisthesis should be distinguished in clinical practice.Clinical Research Information Service of Korea Centers for Disease control and Prevention, KCT0002588. Registered on 12 December 2017, https://cris.nih.go.kr/cris/search/search_result_st01.jsp?seq=10702

The correlation analysis between sagittal alignment and cross-sectional area of paraspinal muscle in patients with lumbar spinal stenosis and degenerative spondylolisthesis

BackgroundThe relationship between spinal alignment and skeletal muscle mass (SMM) has attracted attention in recent years. Sagittal alignment is known to deteriorate with age, but it is not known whether this is related to paraspinal muscles. Therefore, the purpose of this study is to elucidate the role of the multifidus (MF) and psoas major (PS) muscles in maintaining global spinal alignment in patients with lumbar spinal stenosis (LSS) and/or degenerative spondylolisthesis (DS), and to analyze whether each muscles’ cross-sectional area (CSA) correlates with whole-body SMM using bioimpedance analysis (BIA).MethodsWe retrospectively evaluated 140 patients who were hospitalized for surgery to treat LSS and/or DS. Spinal alignment, CSA of spinal muscles, and body composition parameters were measured from full-length standing whole-spine radiography, MRI, and BIA before surgery. The following standard measurements were obtained from radiographs: sagittal balance (C7-SVA), cervical lordosis (CL; C2–C7), lumbar lordosis (LL; L1–S1), thoracic kyphosis (TK; T5–T12), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS).ResultsThe average PS CSA (AveCSA) was highest at L4-L5, whereas MF AveCSA was highest at L5-S1. Paraspinal muscle CSAs were greater in males than in females. There was no statistically significant difference between the left and right CSA for either MF or PS. Correlation coefficient showed strong correlations between the PS AveCSA (L4-L5) and whole body SMM (r = 0.739). Correlation coefficient analysis also showed weak correlation between SMM and PT (r = − 0.184). Furthermore, PS AveCSA (L4-L5) correlated with the PT (r = − 0.183) and age (r = − 0.156), while PT correlated with the whole body SMM (r = − 0.184) but not with age.ConclusionsWhole body SMM showed correlation with PS AvCSA (L4-L5) and with PT among the spinal parameters, which was the same result in MF AvCSA (L4-L5). These findings suggest that the posterior inclination of the pelvis may be correlated with paraspinal muscle area rather than age.

Machine Learning for Automatic Paraspinous Muscle Area and Attenuation Measures on Low-Dose Chest CT Scans

To develop and evaluate an automated machine learning (ML) algorithm for segmenting the paraspinous muscles on chest computed tomography (CT) scans to evaluate for presence of sarcopenia. A convolutional neural network based on the U-Net architecture was trained to perform muscle segmentation on a dataset of 1875 single slice CT images and was tested on 209 CT images of participants in the National Lung Screening Trial. Low-dose, noncontrast CT examinations were obtained at 33 clinical sites, using scanners from four manufacturers. The study participants had a mean age of 71.6 years (range, 70-74 years). Ground truth was obtained by manually segmenting the left paraspinous muscle at the level of the T12 vertebra. Muscle cross-sectional area (CSA) and muscle attenuation (MA) were recorded. Comparison between the ML algorithm and ground truth measures of muscle CSA and MA were obtained using Dice similarity coefficients and Pearson correlations. Compared to ground truth segmentation, the ML algorithm achieved median (standard deviation) Dice scores of 0.94 (0.04) in the test set. Mean (SD) muscle CSA was 14.3 (3.6) cm2 for ground truth and 13.7 (3.5) cm2 for ML segmentation. Mean (SD) MA was 41.6 (7.6) Hounsfield units (HU) for ground truth and 43.5 (7.9) HU for ML segmentation. There was high correlation between ML algorithm and ground truth for muscle CSA (r2 = 0.86; p < 0.0001) and MA (r2 = 0.95; p < 0.0001). The ML algorithm for measurement of paraspinous muscles compared favorably to manual ground truth measurements in the NLST. The algorithm generalized well to a heterogeneous set of low-dose CT images and may be capable of automated quantification of muscle metrics to screen for sarcopenia on routine chest CT examinations.

Predictors of L4−L5 Degenerative Lumbar Spondylolisthesis: L4 Inclination Angle and Facet Joint Angle

To evaluate the relationship between degenerative lumbar spondylolisthesis (DLS) and the L4 inclination angle (IA) and evaluate the risk factors of DLS. Ninety patients with L4-L5 DLS and 90 with L4-L5 lumbar disc herniation or spinal stenosis (control group) were compared. Parameters including L4 IA, facet joint angle (FJA), cross-sectional area of paraspinal muscle, Pfirrmann grading of intervertebral disc, and degeneration grading of facet joint (FJ) were evaluated. The Student t tests and logistic regression analysis were used to analyze the risk factors of DLS. Statistical differences were found in L4 IA, cross-sectional area of multifidus muscle, FJA, and degeneration grading of FJ between 2 groups (P < 0.001, P= 0.07, P < 0.001, and P < 0.001, respectively). The logistic regression analysis demonstrated that greater L4 IA (β:-0.186, P < 0.001), more sagittal FJ (β:-0.117, P < 0.001), and more severe degeneration of FJ (β:-1.033, P < 0.001) were both significant predictors of DLS. Patients with L4 IA greater than 11.15° and FJA greater than 60.19° are more likely to occur DLS.

CT measures of lumbosacral paraspinal muscle size are not correlated with CT measures of lumbosacral stability in military working Labrador Retrievers.

Management of degenerative lumbosacral stenosis in military working dogs more frequently utilizes core conditioning exercise programs. Future research on the effectiveness of these programs may benefit from an improved understanding of relationships between paraspinal muscle size and lumbosacral stability. The aim of this retrospective, secondary analysis, cross-sectional study was to test the following hypotheses related to CT measures: (a) transverse paraspinal muscle area ratios differ between hip flexion and extension, (b) lumbosacral angle and lumbosacral range of motion differ by lumbosacral angle measurement technique, and (c) transverse paraspinal muscle area ratios are correlated with CT measures of lumbosacral stability (parasagittal and parasagittal oblique foraminal area changes) regardless of hip position and with lumbosacral range of motion within each hip position. Lumbosacral CT scans in hip flexion and extension were retrieved from a previous prospective study of military working Labrador Retrievers. A single observer performed triplicate measurements of transverse paraspinal muscle area ratios, parasagittal foraminal area, and parasagittal oblique foraminal area for each hip position and another observer independently performed triplicate measurements of lumbosacral angle and lumbosacral range of motion at L7-S1 using two published techniques. Thirty-nine dogs were analyzed and significant differences were identified between hip flexion and extension for all mean transverse paraspinal muscle area ratio values (P≤.05). Mean lumbosacral angles also significantly differed between the published techniques in both hip flexion and extension. When comparing mean lumbosacral range of motion values, one of the published techniques produced significantly smaller values. No significant correlation was found between transverse paraspinal muscle area ratios and parasagittal foraminal area changes, parasagittal oblique foraminal area changes, or lumbosacral range of motion. These results should be considered when designing studies using these CT measures in military working dogs.

Muscle Gain after Transjugular Intrahepatic Portosystemic Shunt Creation: Time Course and Prognostic Implications for Survival in Cirrhosis

PurposeTo examine the association of transjugular intrahepatic portosystemic shunt (TIPS) creation with muscle gains and patient mortality, and to identify the timeframe of these changes. Materials and MethodsPatients with cirrhosis undergoing TIPS creation with available abdominal computed tomography before and after TIPS from 2004–2015 were included (n = 76). The primary indications for TIPS included refractory ascites (52.6%) or variceal bleeding (47.4%). Axial truncal muscle area and attenuation were measured at the L4 level using free-hand region of interest technique, and pre- and post-TIPS values were compared. The association of TIPS-related muscle changes with mortality was evaluated using Cox multiple regression. Logistic regression analysis was performed to evaluate associations of baseline muscle area and clinical variables with post-TIPS changes. ResultsTIPS creation was associated with significant increases in psoas, paraspinal, and total muscle areas (P < .001, 0.004, and 0.002), and psoas muscle attenuation (P = .022) at a median of 13.5 months after TIPS. Maximal muscle gains occurred within 6 months after TIPS creation (P < .001). Muscle gain at 1-year after TIPS was independently associated with lower mortality (psoas hazard ratio [HR] 0.14, P = .016; paraspinal HR 0.15, P = .016; abdominal HR 0.05, P = .005; core HR 0.06, P = .001; and total HR 0.05, P = .003). Baseline demographic or clinical variables were not associated with muscle gain after TIPS. ConclusionsTIPS creation was strongly associated with truncal muscle gains and attenuation in patients with cirrhosis. Maximal muscle gain occurred within 6 months after TIPS creation. TIPS-related increased muscle mass was independently associated with lower patient mortality.

A Clinical Study on Axial Symptoms and Imaging Changes in Paraspinal Muscles after Cervical Posterior Open-door Laminoplasty.

This research aimed to gain a better understanding of the relationship between cervical posterior open-door laminoplasty on axial symptoms, the net cross-sectional area of paraspinal muscles, and the degree of pimelosis. A retrospective study was conducted on a consecutive series of 37 patients who had underwent cervical posterior open-door laminoplasty + lateral mass fixation and bone graft fusion between January 2015 and July 2015. All patients received postoperative examinations at 6 months and 18 months after the operation. For each follow-up visit, the VAS Rating Scale and ODI Function Index Questionnaire were filled out. Meanwhile, a C-Spine X-ray and MRI of the patients were taken. In the measurements taken with ImageJ 1.51 K Software, the cervical vertebra MRI T2-weighted image cross-section for each segment was measured separately, mainly including the mean T2 signal value of the contour area and the net area of the paraspinal muscles. Differences between VAS and ODI (%) at three different time points were of statistical significance (p < 0.01). Pairwise comparisons of the results showed that VAS and ODI (%) at different times were clearly different (p < 0.01). Differences in the mean T2 signal value and net area at different times were of statistical significance (p < 0.01). Pairwise comparisons of the results indicated that the mean T2 signal value and net area at different times were clearly different (p < 0.01). The corresponding analytical results for VAS, ODI (%), and the mean of the T2 signal value and net area demonstrated that VAS6 months after surgery was positively correlated to the net area of C3/4 and C4/5 (r = 0.352, p < 0.05; r = 0.338, p < 0.05). The analogous analytical results for the mean T2 signal value and net area were of no statistical significance (p > 0.05). We believe that axial symptoms after cervical spine surgery does not affect the recovery of neurological function. There is a process of acute or subacute enlargement of paraspinal muscles on segments C3/4 and C4/5 after the operation, while the results of the follow-up visits show that there is a gradual process of atrophy in local posterior muscles, which may be related to axial symptoms. The degree of pimelosis of the neck paraspinal muscles may have no relationship with axial symptoms.

3:45 PM Abstract No. 287 Increase in muscle mass after transjugular intrahepatic portosystemic shunt (TIPS) creation is a prognostic indicator for survival in cirrhosis

To assess changes in skeletal muscle volume and density after TIPS creation. Patients with cirrhosis undergoing TIPS creation at a single institution between 2004 and 2015, and who had available pre- and post-TIPS contrast-enhanced CT scans, were reviewed (n = 80). Subjects who had received liver transplantation prior to TIPS creation or during the observation period (n = 4) were excluded. Cross sectional muscle area and density (psoas, paraspinal, abdominal wall) were measured with free-hand region of interest at the mid L4 vertebral body level before and after TIPS creation. Differences were compared using the paired t-test. Pairwise correlation analysis was performed to evaluate associations between baseline muscle area and clinical characteristics with post-TIPS changes. Predictors of overall survival were assessed using univariate and multivariate Cox proportional hazard models adjusted for age, sex, HCV infection, hepatocellular carcinoma, diabetes, MELD score and baseline muscle measurements. P values < 0.05 were considered significant. Significant increases in psoas, paraspinal, and total muscle areas were observed after TIPS creation (P <0.001, 0.004, 0.002). A significant increase in post-TIPS psoas muscle attenuation was also observed (3.1 ± 8.5 HU, P = 0.022). In multivariate analysis, increases in psoas (HR = 0.14, P = 0.016), paraspinal (HR = 0.15, P = 0.016), abdominal (HR = 0.05, P = 0.005), core (HR = 0.06, P = 0.001) and total (HR = 0.05, P = 0.003) muscle areas after TIPS creation predicted significantly increased survival rates compared to those with no change. Changes in core muscle area following TIPS creation were not predicted by patient demographics, comorbidities, or pre- and post-TIPS liver function studies. Cross-sectional area of truncal muscles significantly increased after TIPS creation and correlated with improved survival. These parameters can complement other determinants in the assessment of prognosis after TIPS creation. Future research will elucidate the prognostic impact of sarcopenia for TIPS creation, and will increase understanding of potential metabolic changes induced after portosystemic shunting.

MRI-defined paraspinal muscle morphology in Japanese population: The Wakayama Spine Study.

ObjectiveThis study aimed to establish sex- and age-dependent distributions of the cross sectional area and fatty infiltration ratio of paraspinal muscles, and to examine the correlation between paraspinal muscle degeneration and low back pain in the Japanese population.MethodsIn this cross-sectional study, data from 796 participants (241 men, 555 women; mean age, 63.5 years) were analyzed. The measurement of the cross sectional area and fatty infiltration ratio of the erector spinae and multifidus from the level of T12/L1 to L4/5 and psoas major at the level of T12/L1 was performed using axial T2-weighted magnetic resonance imaging. Multivariate logistic regression analysis was used to estimate the association between fatty infiltration of the paraspinal muscles and the prevalence of low back pain.ResultsThe cross sectional area was larger in men than women, and tended to decrease with age, with the exception of the erector spinae at T12/L1 and L1/2 in women. The fatty infiltration ratio was lower in men than women, except for multifidus at T12/L1 in 70–79 year-olds and psoas major in those less than 50 years-old, and tended to increase with age. Logistic regression analysis adjusted for age, sex, and body mass index showed that the fatty infiltration ratio of the erector spinae at L1/2 and L2/3 was significantly associated with low back pain (L1/2 level: odds ratio, 1.05; 95% confidence interval, 1.005–1.104; L2/3 level: odds ratio, 1.05; 95% confidence interval, 1.001–1.113).ConclusionThis study measured the cross sectional area and fatty infiltration ratio of paraspinal muscles in the Japanese population using magnetic resonance imaging, and demonstrated that the fatty infiltration ratio of the erector spinae in the upper lumbar spine was significantly associated with the presence of low back pain. The measurements could be used as reference values, which are important for future comparative studies.

Reduced paraspinous muscle area is associated with post-colectomy complications in children with ulcerative colitis

Background and objectivesSarcopenia, defined as reduced muscle mass, is typically assessed by CT scans, which are infrequently performed in children. Using MRI to measure sarcopenia, we determined the association with postoperative complications after colectomy for ulcerative colitis (UC). MethodsClinical and preoperative MRI data for 13–18-year-old UC patients who underwent colectomy were retrospectively reviewed. Bilateral paraspinous muscle area (PSMA) and psoas muscle area (PMA) at L3 vertebra were measured and averaged. Composite complications were infection, wound dehiscence, postoperative leak/abscess, prolonged ileus, pulmonary embolism, venous thromboembolism, or readmission. ResultsTwenty-nine patients with average age 15.9±1.36years and weight 61.5±19.8kg had a preoperative MRI. The 18/29(62%) with complications had significantly reduced PSMA (4.71±1.44 vs 5.64±1.38cm2, p=0.04) and PMA (7.16±2.60 vs 8.93±2.44, p=0.04). When stratified and compared to highest PSMA, patients with lowest PSMA had increased complication rates (88% vs 29%, p=0.04). There were no differences in age, BMI, albumin, CRP, ESR, or preoperative steroid or anti-TNFα use. Odds of complication in the lowest tertile were 25.0-fold higher than the highest tertile (p=0.04, 95% CI=1.2–520.73). ConclusionThis is the first study to show low PSMA on MRI is associated with complications and increased hospital stay after colectomy in children with UC. Levels of evidenceLevel III retrospective comparative study.

Cervical Paraspinal Muscle Atrophy Rates Following Laminoplasty and Laminectomy with Fusion for Cervical Spondylotic Myelopathy.

Cervical spondylotic myelopathy (CSM) is a disorder that can cause neurologic deterioration. Studies on paraspinal muscular atrophy (PMA) in the lumbar spine have shown that these changes are caused by several perioperative factors. It is possible that PMA in the cervical spine could behave similarly. In this retrospective study, we compared the degree of PMA after laminoplasty versus laminectomy and fusion (LF) using a standard posterior approach to the cervical spine. 18 laminoplasty and 43 LF patients were included in this study. For each patient, preoperative and postoperative MRI files were obtained and transferred into OsiriX imaging software. Atrophy rate was obtained and reported as percentage change in cross-sectional area of the cervical paraspinal muscles from preoperative to postoperative imaging. Mean cross-sectional cervical muscle atrophy rates were 6% and 13.1% for laminoplasty and LF, respectively, representing a 2.19 times increase in the degree of atrophy (P < 0.001). Independently, LF was associated with a 5.84% increase in the rate of PMA (P= 0.03). Involvement of C3 as the cephalad surgical level was associated with a 5.78% decrease in the rate of PMA (P= 0.03). For each degree increase in postoperative Cobb angle, there was a 0.66% decrease in the rate of PMA (P= 0.02). PMA should be part of the decision making process when a posterior approach is considered, inasmuch as this study demonstrates that cervical laminoplasty was associated with significantly lower rates of PMA compared with cervical laminectomy and fusion. Additionally, these results suggest that minimizing PMA may help preserve cervical lordosis.

Biomechanical Modeling of Spine Flexibility and Its Relationship to Spinal Range of Motion and Idiopathic Scoliosis

Study designCross-sectional. ObjectiveTo examine the relationships between spine morphology, spine flexibility, and idiopathic scoliosis. BackgroundGirls have a higher incidence of clinically significant scoliosis than boys, along with smaller vertebrae and greater flexibility. Based on biomechanical modeling, we hypothesized that smaller vertebral width relative to intervertebral disc (IVD) height would be associated with both greater lateral flexibility of the spine and with idiopathic scoliosis. MethodsMagnetic resonance imaging was used to measure IVD height, vertebral width, and paraspinous musculature in 22 girls with mild and moderate idiopathic scoliosis and 29 girls without scoliosis ages 9–13 years. Clinical measurement of maximum lateral bending was also performed in the girls without scoliosis. A simple biomechanical model was used to estimate bending angle from the ratio of IVD height to vertebral half-width for L1–L4. The average ratio (Ravg) and calculated total bending angle (αtot) for L1–L4 were compared to the clinical measurements of lateral bending flexibility in the control group. These measures were also compared between the scoliosis and control groups. ResultsThere was a significant positive relationship between clinical flexibility and both Ravg (p = .041) and αtot (p = .042) adjusting for skeletal age, height, body mass index, and paraspinous muscle area as covariates. The ratio was significantly higher (Ravg = 0.45 vs. 0.38, p < .0001) and the bending angle was significantly greater (αtot = 107° vs. 89°, p < .0001) for girls with scoliosis compared with controls. ConclusionThese results suggest that differences in spine morphology and corresponding changes in spine flexibility may be related to idiopathic scoliosis. If these relationships can be corroborated in larger prospective studies, these easily measured morphologic traits may contribute to a better understanding of the etiology of idiopathic scoliosis and an improved ability to predict scoliosis progression. Level of EvidenceLevel III.

The Cross-Sectional Area of Paraspinal Muscles Predicts the Efficacy of Deep Drain Stimulation for Camptocormia.

Camptocormia, a disturbance of posture, is a well-described clinical feature of PD and other parkinsonian syndromes. Previous reports have shown that DBS of the subthalamic nucleus (STN) or globus pallidus internus is effective in treating camptocormia. However, the efficacy of DBS for camptocormia varies. To determine a clinical marker for selecting an appropriate therapy for camptocormia, a disabling manifestation of Parkinson's disease (PD) that has a variable response to systemic and local therapies. We obtained pre-operative lumbar magnetic resonance imaging of 14 consecutive PD patients with camptocormia who underwent subthalamic nucleus deep brain stimulation (STN-DBS) in this retrospective-designed study. Lumbar MRI was performed three to six months prior to the operation. We measured the cross-sectional area (CSA) and width of each participant's paraspinal muscles. Four (28.6%) patients were effective (EF), five (35.7%) were partially effective (PE), and five (35.7%) were non-effective (NE) to STN-DBS. The lumbar paraspinal CSA and width were significantly larger in the EF group than in the PE and NE groups. The CSA of paraspinal muscles and erector spinae width can be good predictive markers for improving camptocormia in patients with PD after deep brain stimulation.

Does the mesodermal derangement in Chiari Type I malformation extend to the cervical spine? Evidence from an analytical morphometric study on cervical paraspinal muscles.

OBJECTIVE The mesodermal derangement in Chiari Type I malformation (CMI) has been postulated to encompass the cervical spine. The objectives of this study were to assess the cross-sectional areas (CSAs) of cervical paraspinal muscles (PSMs) in patients with CMI without syringomyelia, compare them with those in non-CMI subjects, and evaluate their correlations with various factors. METHODS In this retrospective study, the CSAs of cervical PSMs in 25 patients were calculated on T2-weighted axial MR images and computed as ratios with respect to the corresponding vertebral body areas. These values and the cervical taper ratios were then compared with those of age- and sex-matched non-CMI subjects and analyzed with respect to demographic data and clinicoradiological factors. RESULTS Compared with the non-CMI group, the mean CSA values for the rectus capitis minor and all of the subaxial PSMs were lower in the study group, and those of the deep extensors were significantly lower (p = 0.004). The cervical taper ratio was found to be significantly higher in the study cohort (p = 0.0003). A longer duration of symptoms and a steeper cervical taper ratio were independently associated with lower CSA values for the deep extensors (p = 0.04 and p = 0.03, respectively). The presence of neck pain was associated with a lower CSA value for the deep flexors (p = 0.03). CONCLUSIONS Patients with CMI demonstrate alterations in their cervical paraspinal musculature even in the absence of coexistent syringomyelia. Their deep extensor muscles undergo significant atrophic changes that worsen with the duration of their symptoms. This could be related to a significantly steeper cervical taper ratio that their cervical cords are exposed to. Neck pain in these patients is related to atrophy of their deep flexor muscles. A steeper cervical taper ratio and alterations in the PSMs could be additional indicators for surgery in patients with CMI without syringomyelia.

Back Muscle Morphometry: Effects on Outcomes of Spine Surgery.

This review seeks to synthesize emerging literature on the effects of back muscle size on outcomes in spine surgery. Risk factors that contribute to poor surgical outcomes continue to be an area of interest in spine surgery because proper risk stratification can result in reduction in morbidity and enhanced patient care. However, the impact of muscle size on spine surgical outcomes is an understudied avenue with paucity of data evaluating the relationship among back muscles and surgical outcomes, patient's quality of life, and functional improvement postoperatively. This review was centered around identifying studies that assessed the impact of back muscle size on spine surgery outcomes. Five retrospective studies were selected for review. All studies set out to see if differences in muscle size existed in patients with disparate post-operative outcomes as a primary objective. The studies support the association between larger back muscles and improved outcomes. The size and relative cross sectional area of paraspinal muscles and the size of the psoas muscle were associated with functional outcomes, incidence of complications and also fusion rates. With reduction in surgical complications and improvement in postoperative functional outcomes, back muscle morphometry ought to be included in the preoperative surgical planning as a predictor of outcomes.

Fat Replacement of Paraspinal Muscles with Aging in Healthy Adults.

The aims of this study were to investigate the age-related changes in fatty replacement and cross-sectional area (CSA) of cervical, thoracic, and lumbar paraspinal muscles versus leg muscles in healthy adults and to test for association between muscle fat fraction and lifestyle factors. Fifty-three healthy adults (24-76 yr) were included. Dixon magnetic resonance imaging technique was used to determine CSA and to quantify the fat fraction of paraspinal and leg muscles. Muscle CSA and fat fractions were tested for association with age and muscle strength. The fat fractions were also tested for association with sex, body mass index (BMI), physical activity, and lower back pain. Both paraspinal and leg fat fractions correlated directly with age (P < 0.0001). At all ages, fat fraction was higher in paraspinal than leg muscles. The age-related increase in fat fraction was higher in paraspinal muscles than leg muscles (P < 0.0001). The CSA of the muscles did not correlate with age. Knee extension strength correlated with fat fraction (P < 0.05), and the muscle strength of hip muscles, thigh muscles, and anterior calf muscles correlated with CSA (P < 0.05). Sex was associated with lumbar paraspinal fat fraction (P < 0.05) and BMI with thigh fat fraction (P < 0.001). There was no association between fat fraction and physical activity or lower back pain. The paraspinal muscles were more susceptible to age-related changes than leg muscles. Further, men had significantly lower fat fractions in lumbar paraspinal muscles, and BMI was positively associated with thigh, but not paraspinal, fat fraction.

Repeatability of Computerized Tomography–Based Anthropomorphic Measurements of Frailty in Patients With Pulmonary Fibrosis Undergoing Lung Transplantation

PurposeTo determine interreader and intrareader repeatability and correlations among measurements of computerized tomography–based anthropomorphic measurements in patients with pulmonary fibrosis undergoing lung transplantation. MethodsThis was an institutional review board–approved, Health Insurance Portability and Accountability Act–compliant retrospective study of 23 randomly selected subjects (19 male and 4 female; median age = 69 years; range: 66-77 years) with idiopathic pulmonary fibrosis undergoing pulmonary transplantation, who had also undergone preoperative thoracoabdominal computerized tomography. Five readers of varying imaging experience independently performed the following cross-sectional area measurements at the inferior endplate of the L3 vertebral body: right and left psoas muscles, right and left paraspinal muscles, total abdominal musculature, and visceral and subcutaneous fat. The following measurements were obtained at the inferior endplate of T6: right and left paraspinal muscles with and without including the trapezius muscles and subcutaneous fat. Three readers repeated all measurements to assess intrareader repeatability. ResultsIntrareader repeatability was nearly perfect (interclass correlation coefficients = 0.99, P < 0.001). Interreader agreement was excellent across all 5 readers (interclass correlation coefficients: 0.71-0.99, P < 0.001). Coefficients of variance between measures ranged from 3.2%-6.8% for abdominal measurements, but were higher for thoracic measurements, up to 23.9%. Correlation between total paraspinal and total psoas muscle area was strong (r2 = 0.67, P < 0.001). Thoracic and abdominal musculature had a weaker correlation (r2 = 0.35-0.38, P < 0.001). ConclusionMeasures of thoracic and abdominal muscle and fat area are highly repeatable in patients with pulmonary fibrosis undergoing lung transplantation. Measures of muscle area are strongly correlated among abdominal locations, but inversely correlated between abdominal and thoracic locations.