Can routine MRI spine T1 sequences be used for prediction of decreased bone density?

Background Bone marrow signal is ideally evaluated with magnetic resonance imaging (MRI) due to its high tissue contrast. While advanced MRI quantitative methods can be used for estimating bone density, there are no readily available parameters on routine clinical MRI sequences of the lumbar spine. Purpose To evaluate whether T1 signal intensity (SI) ratio of lumbar vertebral body (VB)/cerebrospinal fluid (CSF) may predict decreased bone density. Material and Methods A retrospective study was conducted. After use of inclusion/exclusion criteria, 36 patients who had an MRI scan of the lumbar spine and a DEXA scan performed as a part of annual health visit were selected. T1 SI of the lumbar vertebral bodies and adjacent CSF were recorded. Ratio of T1 SI of L1–L4 (VB)/CSF was calculated. The corresponding bone-density values on DEXA scan measured as g/cm2 were obtained. Pearson's r correlation statistic was used to determine the correlation between these variables. Results T1 VB/T1 CSF SI ratio was between 1.308 and 2.927 (mean = 2.028). Mean T1 SI value of vertebral bodies (L1–L4) was 264.9 and mean CSF SI value was 131.9. Bone density in g/cm2 was between 0.851 and 1.398 (mean = 1.081). Pearson correlation coefficient was r = −0.619 ( P=0.0001), which shows a negative moderate correlation between the T1 VB/T1 CSF SI ratio and bone density. Conclusion A high T1 VB/T1 CSF SI ratio on routine MRI sequences may indicate decreased bone density. This ratio may be of substantial benefit in unsuspected osteoporosis/osteopenia on routine MRI lumbar spine imaging.

Preclinical Evaluation of a Novel 3D-Printed Movable Lumbar Vertebral Complex for Replacement: In Vivo and Biomechanical Evaluation of Goat Model

Purpose. This was an in vivo study to develop a novel movable lumbar artificial vertebral complex (MLVC) in a goat model. The purpose of this study was to evaluate clinical and biomechanical characteristics of MLVC and to provide preclinical data for a clinical trial in the future. Methods. According to the preoperative X-ray and CT scan data of the lumbar vertebrae, 3D printing of a MLVC was designed and implanted in goats. The animals were randomly divided into three groups: intact, fusion, and nonfusion. In the intact group, only the lumbar vertebrae and intervertebral discs were exposed during surgery. Both the fusion and nonfusion groups underwent resection of the lumbar vertebral body and the adjacent intervertebral disc. Titanium cages and lateral plates were implanted in the fusion group. MLVC was implanted in the nonfusion group. All groups were evaluated by CT scan and micro-CT to observe the spinal fusion and tested using the mechanical tester at 6 months after operation. Results. The imaging results showed that with the centrum, the artificial endplates of the titanium cage and MLVC formed compact bone trabeculae. In the in vitro biomechanical test, the average ROM of L3-4 and L4-5 for the nonfusion group was found to be similar to that of the intact group and significantly higher in comparison to that of the fusion group ( P < 0.05 ). The average ROM of flexion, extension, lateral bending, and rotation in the L2-3 intervertebral space significantly increased in the fusion group compared with the intact group and the nonfusion group ( P < 0.001 ). There were no significant differences in flexion, extension, lateral bending, and rotation between the nonfusion and intact groups ( P > 0.05 ). The average ROM of flexion, extension, lateral bending, and rotation in the L2-5 intervertebral space was not significantly different between the intact group, the fusion group, and the nonfusion group, and there was no statistical significance ( P > 0.05 ). HE staining results did not find any metal and polyethylene debris caused by abrasion. Conclusion. In vivo MLVC can not only reconstruct the height and stability of the centrum of the operative segment but also retain the movement of the corresponding segment.

Anatomy of the Spinal Cord

The spinal cord begins as the cervical cord immediately below the medulla and extends through the spinal canal, where it becomes the thoracic, lumbar, sacral, and coccygeal parts of the cord. In most persons, the spinal cord proper ends at the lower portion of the first lumbar vertebral body, where it forms the conus medullaris and, finally, the filum terminale. A cervical enlargement contains the innervation pathways of the upper limbs; a lumbar enlargement contains the pathways of the lower limbs. This chapter reviews ascending and descending pathways in the spinal cord.

Depletion of skeletal muscle mass adversely affects long-term outcomes for men undergoing gastrectomy for gastric cancer

Background Although low skeletal muscle mass has an adverse impact on the treatment outcomes of cancer patients, whether the relationship between preoperative skeletal muscle mass and gastrectomy outcomes in gastric cancer (GC) differs between men and women is unclear. The study aimed to clarify this relationship based on gender. Methods Between January 2007 and December 2015, 1054 patients who underwent gastrectomy for GC at Osaka City General Hospital were enrolled in this study. We evaluated sarcopenia by the skeletal muscle index (SMI), which was measured by computed tomography (CT) using areas of muscle in the third lumbar vertebral body (L3). Male and female patients were each divided into two groups (low skeletal muscle and high skeletal muscle). Results The SMI emerged as an independent predictor of 5-year overall survival (OS) in male GC patients (Hazard ratio 2.51; 95% confidence interval (CI) 1.73–3.63, p < 0.001) based on multivariate analysis. However, this index was not an independent predictive determinant of 5-year cancer-specific survival (CSS). The SMI was not an independent predictor of either OS or CSS in female GC patients. The incidence of leakage and major complication (Clavien Dindo grade ≧ 3) did not differ significantly across groups. Conclusions Preoperative skeletal muscle mass is a valuable prognostic predictor of OS in male GC patients.

Risk Factor Analysis of Bone Cement Leakage for Polymethylmethacrylate-Augmented Cannulated Pedicle Screw Fixation in Spinal Degenerative Diseases

Background We investigated the risk factors of cement leakage (CL) for polymethylmethacrylate-augmented cannulated pedicle screw (CPS) in spinal degenerative diseases and provided technical guidance for clinical surgery. Methods This study enrolled 276 patients with spinal degenerative disease and osteoporosis who were augmented using CPSs (835 screws in total) from May 2011 to June 2018 in our hospital. The patients' age, sex, bone mineral density (BMD), diagnosis, augmented positions, number of CPS implanted, and CL during surgery were recorded. CL was observed by postoperative computed tomography (CT) and was classified by Yeom typing. Results A total of 74 (8.9%) CPSs in 64 patients leaked (23.2%), with 65 (87.83%), 3 (4.05%), and 6 (8.11%) screws showing Types S, B, and C leakage, respectively. CL was significantly correlated with the number and position of screws (P < 0.05), but not with sex, age, and BMD (P > 0.05). The position, number of CPSs, fracture, degenerative scoliosis, ankylosing spondylitis, and revision surgery were risk factors for CL (P < 0.05). Augmentation of the thoracic vertebral body, fracture, and ankylosing spondylitis were independent risk factors for Type S. Augmentation of the lumbar vertebral body, lumbar disc herniation, and lumbar spondylolisthesis were independent risk factors for Type B (P < 0.05). Conclusions CL has a high incidence in clinical practice. To avoid serious complications, high-risk factors for leakage should be addressed. Particularly, it is necessary to develop alternative solutions for the lack of holding force of internal fixation caused by CL during surgery.

Sarcopenia as a predictor of postoperative complications in patients with pancreatic cancer

Several studies showed that sarcopenia is associated with an increase of postoperative complications, with worse postoperative results in patients with pancreatic cancer. According to European Working Group on Sarcopenia, it is a "progressive and generalized skeletal muscle loss" characterized by both loss of skeletal muscle mass and strength (Cruz-Jentoft AJ et al., 2019). Aim of our work was to evaluate the effect of sarcopenia on the occurrence of postoperative complications after pancreatic resections in patients with pancreatic and periampullary cancer. We performed a retrospective analysis of treatment of 152 patients who underwent radical pancreatic resections. Sarcopenia was determined by preoperative computed tomography using the Hounsfield Unit Average Calculation (HUAC). In our investigation we measured the psoas area and density (Hounsfield Units) at the level of the third lumbar vertebral body (L3). Sarcopenia was diagnosed in 66 (43.4%) patients. Among patients with sarcopenia complications occurred in 41 (62.1%), mortality was 4 (6.1%). In the group of patients without sarcopenia, complications occurred in 29 (33.7%) of 86 patients, mortality was 2 (2.3%). The level of postoperative complications in patients with sarcopenia was significantly higher (c2 =12.1, p=0.0005). Postoperative mortality in patients with sarcopenia was higher without significant difference (c2 =1.3, p=0.24). Sarcopenia significantly affects the level of postoperative complications and its detection can be used to improve the selection of patients before pancreatic resections in patients with pancreatic cancer.

Sarcopenia prior to and following chemotherapy to predict morbidity in patients undergoing post-chemotherapy retroperitoneal lymphadenectomy (PC-RPLND).

381 Background: Patients undergoing post-chemotherapy retroperitoneal lymphadenectomy (PC-RPLND) are subject to variable but substantial risks. Unlike those patients undergoing other extirpative GU surgeries, patients undergoing PC-RPLND are usually younger and possess fewer co-morbidities. Despite this, the burden of metastatic disease and the effects of pre-operative chemotherapy may leave patients poorly conditioned prior to undergoing surgery. Sarcopenia has previously been demonstrated to predict adverse clinical outcomes in a variety of abdominal surgeries. We hypothesized that sarcopenia would be similarly predictive of morbidity and mortality in patients undergoing PC-RPLND. Methods: The records of all patients undergoing post-chemotherapy retroperitoneal lymphadenectomy for the treatment of metastatic germ cell tumors at both a public safety net hospital and an academic tertiary medical center were reviewed. Sarcopenia was assessed by measuring cross sectional area of the psoas muscle at the middle of the third lumbar vertebral body on pre-chemotherapy and preoperative computerized tomography. Psoas Muscle Index (PMI) was calculated by adjusting total psoas area for patient height (cm2/m2). Univariate and multivariate analysis was performed to assess the predictive value of sarcopenia for morbidity and mortality following PC-RPLND. Results: 90 patients underwent PC-RPLND from the year 2006-2019, of whom 81 patients had both pre-chemo and preoperative cross sectional imaging available. Prior to chemotherapy the mean PMI for this cohort was 7.32 cm2/m2, and this did not significantly change following chemotherapy mean PMI = 7.06 cm2/m2 (p = 0.44). Lower PMI both prior to (p = 0.05) and following chemotherapy (p = 0.03) were predictive of a higher risk of post-operative complication. There was a trend towards longer hospital length of stay in patients with more significant sarcopenia, however this was not clinically significant (p = 0.09). Conclusions: Sarcopenia was predictive of morbidity in patients undergoing PC-RPLND. Although sarcopenia did worsen following chemotherapy this was not statistically significant. Further assessment of sarcopenia and pre-operative nutritional status in this population may provide opportunities to reduce morbidity following PC-RPLND.

Image classification of osteoporotic vertebral fracture with endplate-disc complex Injury

Background The purpose of this study was to use MRI and CT to observe osteoporosis vertebral fracture (OVF) combined with endplate-disc complex (EDC) injury and to classify the degree of EDC injury according to the changes in EDC signal intensity and morphology on the images. Methods We investigated the incidence of EDC injury, observed the morphology and signal intensity changes of EDC injury using MRI and CT, and graded the injuries from 0 to 4 according to their severity. We compared whether there were differences in the degree of EDC injury among different vertebral fractures, bone mineral density(BMD), and severity of vertebral fractures. Results A total of 479 patients were included in this study, of whom 321 had EDC injury adjacent to the fractured vertebral body. Among those, 158 cases were grade 0, 66 cases were grade 1, 72 cases were grade 2, 78 cases were grade 3, and 92 cases were grade 4. The degree of EDC injury associated with thoracolumbar vertebral fractures was more serious than that of EDC injuries associated with thoracic and lumbar vertebral body fractures. Vertebral fractures with severe osteoporosis were associated with more severe EDC injury. Additionally, the more severe the vertebral fracture, the more severe was the combined EDC injury. Conclusion This study found that the incidence rate of EDC injury reached 67.0%. Among patients with OVF, severe osteoporosis and severe fractures in the thoracolumbar segments were often associated with more severe EDC injury.