Kinetic magnetic resonance imaging analysis of lumbar segmental motion at levels adjacent to disc herniation.

PURPOSE: A retrospective radiographic study was carried out to analyze the effect of lumbar disc herniation on the kinetic motion of adjacent segments. METHODS: A total of 162 patients with low back pain or radicular pain in the lower limbs without a prior history of surgery were evaluated using kinetic magnetic resonance imaging. Translational motion, angular variation, and disc height were measured at each segment from L1-L2 to L5-S1. Other factors including the degree of disc degeneration, age, gender, and vertebral segment location were analyzed to determine any predisposing risk factors for segmental instability adjacent to disc herniations. RESULTS: Spinal levels above the disc herniation exhibited, on average, a 6.4 % increase in translational motion per mm of disc herniation (P = 0.496) and a 21.4 % increase in angular motion per mm herniation (P = 0.447). Levels below the herniation demonstrated a 5.2 % increase in translational motion per mm of disc herniation (P = 0.428) and a decrease of 10.7 % in angular motion per mm (P = 0.726). The degree of disc degeneration had no significant correlation with adjacent level motion. Similarly, disc herniation was not significantly correlated with disc height at adjacent levels, although there was a significant relationship between gender and adjacent segment disc height. CONCLUSIONS: Although disc height, translational motion, and angular variation are significantly affected at the level of a disc herniation, no significant changes are apparent in adjacent segments. Our results indicate that herniated discs have no effect on range of motion at adjacent levels regardless of the degree of disc degeneration or the size of disc herniation, suggesting that the natural progression of disc degeneration and adjacent segment disease may be separate, unrelated processes within the lumbar spine.

Secreted phosphoprotein 24 kD (Spp24) inhibits growth of human pancreatic cancer cells caused by BMP-2.

The emerging role of bone morphogenetic proteins (BMPs) in the initiation and progression of multiple cancers has drawn great attention in cancer research. In this study, we report that BMP-2 can promote the proliferation of the pancreatic tumor cell line, PANC-1. Secreted phosphoprotein 24 kD (Spp24), a BMP binding protein, did not affect the proliferation of the cells but promoted the apoptosis of the cells in vitro. In a xeneograft tumor model using PANC-1 cells, BMP-2 dramatically promoted tumor growth, while Spp24 not only abolished the effect of BMP-2, but also dramatically induced tumor shrinking when used alone. Activation of Smad1/5/8 participated in this process as demonstrated by immunohistochemical staining of phosphorylated Smad 1/5/8. We conclude that Spp24 can be developed into a therapeutic agent that could be employed in clinical situations where the inhibition of BMPs and related proteins is advantageous.

The evaluation of cervical spine mobility without significant spondylosis by kMRI.

STUDY DESIGN: Retrospective analysis of kinetic magnetic resonance images (kMRI). OBJECTIVE: To analyse the kinematics of cervical spine inpatients without significant spondylosis and to understand the normal movement of the cervical spine as reference for future comparison. SUMMARY OF BACKGROUND DATA: Although some studies have been conducted to describe the normal mobility of the cervical spine, prior studies did not establish a relationship between the kinematics of cervical spine and disc degeneration. Only a few studies of the kinematics of the non-degenerated cervical spine have been reported; however, they focused on single level and not all the levels of cervical spine. METHODS: 468 symptomatic patients underwent upright cervical kMRI, and cervical disc degeneration was evaluated with a new grading system. This grading system consists of four grades (0-III), and the cervical spines with grade 0 and grade I discs were included in this study. Finally, 61 symptomatic patients were studied 34 male and 27 female with an average age of 41.9 years. kMRI was used to define the normal mobility of the cervical spine by calculating the translation motion, angular variation and percentage angular contribution to the total cervical spine. RESULTS: The translation motion of the cervical spine at each level was 0.85 ± 1.22 mm at C2/3, 1.05 ± 1.19 mm at C3/4, 0.63 ± 1.19 mm at C4/5, 0.57 ± 0.91 mm at C5/6, 0.16 ± 0.86 mm at C6/7 and -0.11 ± 0.81 at C7/T1. In general, the translation motion decreased from proximal segment to distal segment. The angular variation of the cervical spine at each level was 5.58 ± 3.86° at C2/3, 8.26 ± 4.81° at C3/4, 9.11 ± 4.87° at C4/5, 10.05 ± 5.26° at C5/6, 8.31 ± 4.30° at C6/7 and 4.87 ± 3.28° at C7/T1. The angular variation at C2/3 and C7/T1 was significantly lower compared to other levels (P < 0.05). The contribution of each cervical level to the total angular mobility of cervical spine was the greatest at C5/6 (21.68 ± 10.31%) and least at C7/T1 (11.11 ± 7.60%) (P < 0.05). CONCLUSION: This study demonstrates the normal cervical segmental mobility for the entire cervical spine using kMRI. These results will be helpful to understand the normal mobility of the cervical spine and for understanding the relationship between kinematics of the cervical spine and disc degeneration for future comparisons.

The effect of aging on posterior intertransverse lumbar fusion: a New Zealand white rabbit model.

STUDY DESIGN: In vivo assessment of lumbar spinal fusion between a younger and older cohort of New Zealand white rabbits. OBJECTIVE: Directly compare fusion within young and aged New Zealand white rabbits to establish an aged spinal fusion model translational research. SUMMARY OF BACKGROUND DATA: Prior studies have utilized skeletally mature young rabbits (6-12 mo old) that may not be appropriate as an analog for studying the aging human spine. METHODS: Ten aged (>36 mo old) and 10 young (12 mo old) New Zealand white rabbits underwent a single-level, bilateral, L5-6 posterolateral intertransverse fusion using autogenous iliac crest bone graft. The animals were killed at 6 weeks postoperatively, and the specimens were then evaluated with quantitative microcomputerized tomography and manual palpation by 6 orthopedic surgeons. The fusions were graded as either fused or not fused by each examiner. The spines were then embedded in poly(methyl methacrylate) and cut into 2-mm-thick sections for histologic analysis. RESULTS: A higher percentage of young rabbits were determined to be successfully fused through manual palpation testing compared with the aged rabbits. Micro-computed tomography (CT) analysis revealed a significantly greater fusion mass volume in the younger rabbits than in the older cohort. In addition, the fusion density of the younger rabbits was found to be significantly lower than that of the older rabbits when normalized to the bone density in the nonfused portion of the spine. Histologic analysis showed that the quality of the bone within the fusion mass was consistent between the young and old rabbits. A greater number of young animals had bilateral continuous bone graft compared with the aged animals. CONCLUSIONS: The aged (>36 mo) New Zealand white rabbit model appears to be a valid model to evaluate the effect of aging on lumbar fusion and has the potential to more accurately model conditions that are present in the older human spine.

The effect of bone morphogenetic protein-2 injection at different time points on intervertebral disk degeneration in a rat tail model.

STUDY DESIGN: Prospective in vivo rat tail model of disk degeneration comparing the effects of recombinant human bone morphogenetic protein-2 (rhBMP-2) injection over various time points and grades of degeneration. OBJECTIVE: To evaluate the effect of timing and disk grade on rhBMP-2 injection in a rat tail model of disk degeneration. SUMMARY OF BACKGROUND DATA: rhBMP-2 stimulates the proliferation of intervertebral disk cells and the secretion of extracellular matrix. However, few in vivo studies have demonstrated whether rhBMP-2 also improves disk degeneration and the severity of disk degeneration beyond which disks cannot be recovered by rhBMP-2 treatment. METHODS: Two coccygeal disks of each rodent subject were punctured percutaneously using an 18 G needle. At 4 weeks after the puncture, disks demonstrating induced degeneration were divided into 3 groups. Groups 1, 2, and 3 were treated with 7.5 µg rhBMP-2 or phosphate buffered saline by injection into the disk at 4, 6, and 8 weeks postpuncture, respectively. Plain radiographs and magnetic resonance images (MRIs) were obtained on the day of puncture and every 2 weeks thereafter until sacrifice. At 6 weeks after injection, each group was killed and examined with histologic and immunohistochemical analysis. RESULTS: According to MRI disk grade evaluation of the degenerative disk, rhBMP-2 significantly improved degeneration grade in group 1 at 2 weeks after injection. According to radiographic disk height index, groups 1 and 2 showed a trend toward improvement at 2 weeks after rhBMP-2 injection. Chondrogenic differentiation was noted on immunohistochemical staining of many disks treated with rhBMP-2. CONCLUSIONS: rhBMP-2 injection of degenerated disks at 4 weeks postpuncture induced a transient improvement in disk grade on MRI and stimulated chondrogenic differentiation. These data suggest rhBMP-2 as a potential therapy for degenerative disk disease.

Effect of Modic changes on spinal canal stenosis and segmental motion in cervical spine.

PURPOSE: Few studies have reported the characteristics of Modic changes (MCs) in the cervical spine in contrast to the lumbar spine. The purpose of this study was to identify the prevalence of MCs in the cervical spine and to elucidate the relationship of MCs with spinal canal stenosis and angular motion. METHODS: 437 consecutive, symptomatic patients with neck pain with or without neurogenic symptoms were included in this study. MRI in multiple positions was performed with dynamic motion of the cervical spine in upright, weight-bearing neutral, flexion and extension positions. Type of MC, intervertebral disc degeneration grade, spinal cord compression grade and sagittal angular motion between flexion and extension for each segment from C2-3 to C6-7 were evaluated. RESULTS: MCs were observed in 84 out of 437 patients (19.2%) and in 109 out of 2,185 motion segments (5.0%) with type 2 changes predominating. Disc degeneration grades and spinal cord compression grades of segments with MCs were significantly higher than those without MCs. Sagittal angular motion of segments with MCs were significantly lower than those without MCs. Multiple logistic regression analysis revealed that significantly elevated odds ratios for MCs were observed in segments with severe disc degeneration, severe spinal canal compression and less angular motion. CONCLUSION: The cervical segments with MCs were significantly more likely to have disc degeneration and spinal canal stenosis. In addition, the segments with MCs had significantly less angular motion, which suggests MCs may correlate with loss of mobility.

Missed cervical disc bulges diagnosed with kinematic magnetic resonance imaging.

PURPOSE: To determine if adding flexion and extension MRI studies to the traditional neutral views would be beneficial in the diagnosis of cervical disc bulges. METHODS: Five hundred patients underwent MRI in neutral, flexion and extension positions. The images were analyzed using computer software to objectively quantify the amount of disc bulge. RESULTS: Compared to the neutral position, cervical disc bulges were significantly increased in the extension position (P < 0.05), but on flexion position, there was no significant difference (P > 0.05). For patients without or <3 mm of disc bulge in neutral, 2.97% demonstrated an increase in bulge to ≥3 mm bulge in flexion, and 16.41% demonstrated an increase to ≥3 mm bulge in extension. For patients in the neutral view that had a baseline disc bulge of 3-5 mm, 3.73% had increased bulges to ≥5 mm in flexion and 11.57% had increased bulges to ≥5 mm in extension. CONCLUSION: A significant increase in the degree of cervical disc bulge was found by examining extension views when compared with neutral views alone. Kinematic MRI views provide valuable added information, especially in situations where symptomatic radiculopathy is present without any abnormalities demonstrated on traditional neutral MRI.

Measuring the impact of the Thoracolumbar Injury Classification and Severity Score among 458 consecutively treated patients.

CONTEXT: The Thoracolumbar Injury Classification and Severity Score (TLICS) was proposed to improve injury classification and guide surgical decision-making of thoracolumbar spinal trauma (TLST), but its impact on the care of patients has not been quantified. STUDY DESIGN: Retrospective study. PATIENT SAMPLE: Analysis of 458 patients treated for TLST trauma from 2000 through 2010 at a single center. Outcome measures Neurological status - ASIA Impairment Scale (AIS), failure of conservative treatment, and surgical complications. METHODS: Clinical and radiological data were evaluated. Patients were grouped according to the period before (2000-2006) and after (2007-2010) utilization of the TLICS. RESULTS: From 2000 to 2006, 148 patients were initially treated conservatively (C) and 66 were surgically (S) treated. In the C group, the TLICS ranged from 1 to 7 (median 1; mean 1.57). In the S group, the TLICS ranged from 2 to 10 (median 2; mean 4.14). The TLICS matched treatment in 97.9% of conservatively treated patients. From 2007 to 2010, 162 patients were initially treated C and 82 were treated S. In the C group, the TLICS ranged from 1 to 4 (median 1; mean 1.48). In the S group, the TLICS ranged from 2-10 (median 4; mean 4.4). The TLICS matched treatment in 98.8% of C-treated patients. Overall, failure of C treatment occurred in nine patients; most failures (7/9) and all three missed distractive injuries occurred prior to use of the TLICS. CONCLUSIONS: After introduction of the TLICS, there was a trend towards more successful conservative treatment with fewer conversions to surgical treatment.

Radiographic Thigh Muscle Measurements Are a Reliable Predictor of Psoas Area and Sarcopenia.

BACKGROUND: Sarcopenia is associated with falls, fractures, postoperative complications such as periprosthetic joint infections and dislocations, and early mortality. Although cross-sectional imaging is currently used to diagnose sarcopenia, inexpensive and widely available screening tests are needed. The goal of this study was to investigate whether measurements of thigh muscles made on radiographs can predict psoas muscle area and the presence of sarcopenia as determined on computed tomography (CT) scans. METHODS: A retrospective radiographic review was performed to measure thigh muscle area in the coronal and sagittal planes using the differential in soft-tissue attenuation. Psoas muscle area on CT at L3 and L4 served as the gold standard for the diagnosis of sarcopenia. The correlation between thigh muscle and psoas muscle areas was determined, and multivariable models were developed to identify predictors of psoas muscle area and sarcopenia. RESULTS: Four hundred and fourteen patients (252 male, 162 female) were identified. Seventy-six (18.4%) of the patients had an L4 psoas muscle area below the sex-specific cutoff value for sarcopenia. Patients with sarcopenia on abdominal CT had significantly smaller thigh muscle measurements on all radiographic views. The mean and standard deviation of the thigh muscle measurements were determined for the entire cohort and for patients with sarcopenia, as well as for adults aged 18 to 40 years without sarcopenia to provide normative reference values. The intraclass correlation coefficients were >0.8 for all radiographic measurements. The anteroposterior-view measurement of thigh muscle width and lateral-view measurement of quadriceps height were identified as independent predictors of both psoas muscle area and sarcopenia. CONCLUSIONS: Measurements of thigh muscle size made on radiographs can predict both psoas muscle area and sarcopenia. These measurements are a reliable and readily available screening tool to aid in the diagnosis and treatment of sarcopenia in the orthopaedic population. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Traumatic spinal injury patterns of on vs. off-road motorcycle crashes.

OBJECTIVE: Two wheel motorized vehicles used in both street transportation and recreation are a common cause of severe injury in the United States (US). To date, there has been limited data describing the spinal injury patterns among these motorcycle injury patients in the US. The goal of this study is to characterize and compare differences in specific injury patterns of patients sustaining traumatic spinal injuries after motocross (off-road) and street bike (on-road) collisions in the southwestern US at a Level I Trauma Center. METHODS: Trauma registry data was queried for patients sustaining a spinal injury after motorcycle collision from 2010 to 2019 at a single Level I Trauma Center. Computed tomography (CT) scan and magnetic imaging resonance imaging (MRI) reports from initial trauma evaluation were reviewed and data was manually obtained regarding injury morphology and location. RESULTS: A total of 1798 injuries were identified in 549 patients who sustained a motorcycle collision, specifically 67 off-road and 482 on-road motorcycle patients. Off-road motorcycle patients were found to be significantly younger (34.75 vs. 42.66, p = 0.00015). A total of 46.2% of the off-road injuries were determined to be from compression mechanisms, compared to 32.9% in the on-road cohort (p = 0.0027). The on-road cohort was more likely to have an injury classified as insignificant, such as transverse and spinous process fractures (60.1% vs. 42.5%, p = 00.25). There was no significant difference in regards to junctional, mobile, and semirigid spine segments between the two cohorts. CONCLUSIONS: Different fracture patterns were seen between the off-road and on-road motorcycle cohorts. Off road motorcyclists experienced significantly more compression and translational injuries, while on road motorcyclists experienced more frequent insignificant injury patterns. Data on the different fracture patterns may help professionals develop safety equipment for motorcyclists.

Secreted phosphoprotein 24 kD (Spp24) inhibits the growth of human osteosarcoma through the BMP-2/Smad signaling pathway.

Autocrine stimulation of tumor cells is an important mechanism for the growth of skeletal tumors. In tumors that are sensitive, growth factor inhibitors can dramatically reduce tumor growth. In this study, our aim was to investigate the effects of Secreted phosphoprotein 24 kD (Spp24) on the growth of osteosarcoma (OS) cells in the presence and absence of exogenous BMP-2 both in vitro and in vivo. Our study demonstrated that Spp24 inhibited proliferation and promoted apoptosis of OS cells as confirmed by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay and immunohistochemical staining. We found that BMP-2 increased the mobility and invasiveness of tumor cells in vitro whereas Spp24 inhibited both of these processes alone and in the presence of exogenous BMP-2. Phosphorylation of Smad1/5/8 and Smad8 gene expression was enhanced by treatment with BMP-2 but inhibited by treatment with Spp24. Subcutaneous and intratibial tumor models in nude mice demonstrated that BMP-2 promoted OS growth in vivo, while Spp24 significantly inhibited tumor growth. We conclude that the BMP-2/Smad signaling pathway is involved in the pathogenesis of OS growth and that Spp24 inhibits the growth of human OS induced by BMP-2 both in vitro and in vivo. Interruption of Smad signaling and increased apoptosis appear to be the primary mechanisms involved. These results confirm the potential of Spp24 as a therapeutic agent for the treatment of OS and other skeletal tumors.

Spinopelvic dissociation as a complication of iliac crest bone graft harvest using an acetabular reamer.

STUDY DESIGN: Descriptive case report. OBJECTIVE: To report spinopelvic dissociation as a complication of autogenous bone graft harvest with the use of an acetabular reamer. SUMMARY OF BACKGROUND DATA: Iliac crest bone graft harvest has been previously described in orthopedic literature with overall complication rates of 0% to 39%. Complications are inconsistently separated into "minor" and "major" groups, commonly reporting hematoma, infection, and injury to the superior gluteal artery or nerve. No reports of spinopelvic dissociation, a well known injury in the traumatic setting, have been reported. METHODS: We report the case of 1 patient who presented with spinopelvic dissociation after autogenous bone graft harvest with the use of an acetabular reamer. RESULTS: We present a unique case in which fracture through the reamer harvesting site led to complete disruption of the posterior pelvic ring on the operative side. Subsequent attempted closed management led to failure through the osteoporotic anterior pelvic ring on the operative side and the posterior pelvic ring on the contralateral side, leading to progressive instability, disability, and pain. This was successfully addressed with lumbopelvic fusion and 2-year follow-up is presented. CONCLUSIONS: The potential hazard of acetabular reamer bone graft harvest is discussed, and primary operative fixation of harvest-related fractures is suggested.

Patterns of Lumbar Disc Degeneration: Magnetic Resonance Imaging Analysis in Symptomatic Subjects.

STUDY DESIGN: Cross-sectional study. PURPOSE: To evaluate lumbar disc degeneration (LDD) on magnetic resonance imaging (MRI) in symptomatic subjects to accumulate baseline data on the pattern of degeneration. OVERVIEW OF LITERATURE: LDD plays an important role in the diagnosis and treatment of low-back pain in patients. Few studies have focused on the pattern of LDD to understand how the lumbar spine ages. METHODS: This study included 1,095 patients (mean age, 44.29 years; range, 16-85 years) who underwent upright lumbar MRI. LDD was graded into five categories (I-V). Positive LDD was defined as grade III or greater. The prevalence and pattern of LDD were analyzed, and the correlations between age and total grade of LDD were evaluated. RESULTS: The average number of LDD levels and the total grade of LDD increased with age. LDD moved cephalad with age. The rate of LDD increased rapidly during the decade before the prevalence of LDD and became >50%. In the single-level LDD group, the levels L5-S1 were the most common levels (60.3%). In the two-level group, L4-L5 and L5-S1 were the most common levels (53.5%). In the three-level group, L3-L4, L4-L5, and L5-S1 were the most common levels (55.7%). In the multilevel LDD group, contiguous multilevel disc degeneration (CMDD) was more common than the skipped level disc degeneration (SLDD). The levels L4-L5 were the most common levels in the CMDD group, and L5-S1 were the most common levels among SLDD. CONCLUSIONS: LDD was found to correlate with age, and the specific patterns and rates of LDD depended on lumbar disc level and age. These LDD pattern data can be used before spinal procedures to predict the probability of natural LDD progression with age.

Preoperative Maximization to Reduce Complications in Spinal Surgery.

STUDY DESIGN: Invited narrative review. OBJECTIVES: The aim of this review was to summarize current literature regarding risk factors that surgeons can optimize in the preoperative setting in the spinal surgery patient, in order to reduce complications and improve patient-reported outcomes. METHODS: Review of the relevant literature by the authors. RESULTS: Modifiable risk factors identified relative to the patient include obesity, malnutrition/nutrient deficiency, diabetes/hyperglycemia, preoperative anemia, vitamin D/DEXA (dual-energy radiograph absorptiometry), nicotine use/smoking, and opioid use/psychosocial factors. CONCLUSION: By maximizing a patient's physiological and psychological status prior to elective spine surgery, we may move closer to achieving the goals of value-based care: improving patient-reported outcomes while decreasing the cost of care.

Minimizing Blood Loss in Spine Surgery.

STUDY DESIGN: Broad narrative review. OBJECTIVE: To review and summarize the current literature on guidelines, outcomes, techniques and indications surrounding multiple modalities of minimizing blood loss in spine surgery. METHODS: A thorough review of peer-reviewed literature was performed on the guidelines, outcomes, techniques, and indications for multiple modalities of minimizing blood loss in spine surgery. RESULTS: There is a large body of literature that provides a consensus on guidelines regarding the appropriate timing of discontinuation of anticoagulation, aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and herbal supplements prior to surgery. Additionally, there is a more heterogenous discussion the utility of preoperative autologous blood donation facilitated by erythropoietin and iron supplementation for healthy patients slated for procedures with high anticipated blood loss and for whom allogeneic transfusion is likely. Intraoperative maneuvers available to minimize blood loss include positioning and maintaining normothermia. Tranexamic acid (TXA), bipolar sealer electrocautery, and topical hemostatic agents, and hypotensive anesthesia (mean arterial pressure (MAP) <65 mm Hg) should be strongly considered in cases with larger exposures and higher anticipated blood loss. There is strong level 1 evidence for the use of TXA in spine surgery as it reduces the overall blood loss and transfusion requirements. CONCLUSION: As the volume and complexity of spinal procedures rise, intraoperative blood loss management has become a pivotal topic of research within the field. There are many tools for minimizing blood loss in patients undergoing spine surgery. The current literature supports combining techniques to use a cost- effective multimodal approach to minimize blood loss in the perioperative period.

Local and global subaxial cervical spine biomechanics after single-level fusion or cervical arthroplasty.

An experimental in vitro biomechanical study was conducted on human cadaveric spines to evaluate the motion segment (C4-C5) and global subaxial cervical spine motion after placement of a cervical arthroplasty device (Altia TDI,Amedica, Salt Lake City, UT) as compared to both the intact spine and a single-level fusion. Six specimens (C2-C7) were tested in flexion/extension, lateral bending, and axial rotation under a +/- 1.5 Nm moment with a 100 N axial follower load. Following the intact spine was tested; the cervical arthroplasty device was implanted at C4-C5 and tested. Then, a fusion using lateral mass fixation and an anterior plate was simulated and tested. Stiffness and range of motion (ROM) data were calculated. The ROM of the C4-C5 motion segment with the arthroplasty device was similar to that of the intact spine in flexion/extension and slightly less in lateral bending and rotation, while the fusion construct allowed significantly less motion in all directions. The fusion construct caused broader effects of increasing motion in the remaining segments of the subaxial cervical spine, whereas the TDI did not alter the adjacent and remote motion segments. The fusion construct was also far stiffer in all motion planes than the intact motion segment and the TDI, while the artificial disc treated level was slightly stiffer than the intact segment. The Altia TDI allows for a magnitude of motion similar to that of the intact spine at the treated and adjacent levels in the in vitro setting.

Thoracolumbar spine trauma classification: the Thoracolumbar Injury Classification and Severity Score system and case examples.

OBJECT: The aim of this study was to review the Thoracolumbar Injury Classification and Severity Score (TLICS) and to demonstrate its application through a series of spine trauma cases. METHODS: The Spine Trauma Study Group collaborated to create and report the TLICS system. The TLICS system is reviewed and applied to 3 cases of thoracolumbar spine trauma. RESULTS: The TLICS system identifies 3 major injury characteristics to describe thoracolumbar spine injuries: injury morphology, posterior ligamentous complex integrity, and neurological status. In addition, minor injury characteristics such as injury level, confounding variables (such as ankylosing spondylitis), multiple injuries, and chest wall injuries are also identified. Each major characteristic is assigned a numerical score, weighted by severity of injury, which is then summated to yield the injury severity score. The TLICS system has demonstrated initial success and its use is increasing. Limitations of the TLICS system exist and, in some instances, have yet to be addressed. Despite these limitations, the severity score may provide a basis to judge spinal stability and the need for surgical intervention. CONCLUSIONS: By addressing both the posterior ligamentous integrity and the patient's neurological status, the TLICS system attempts to overcome the limitations of prior thoracolumbar classification systems. The TLICS system has demonstrated both validity and reliability and has also been shown to be readily learned and incorporated into clinical practice.

Bone morphogenetic protein-2 promotes osteosarcoma growth by promoting epithelial-mesenchymal transition (EMT) through the Wnt/ß-catenin signaling pathway.

The correlation between BMP-2 and osteosarcoma growth has gained increased interest in the recent years, however, there is still no consensus. In this study, we tested the effects of BMP-2 on osteosarcoma cells through both in vitro and in vivo experiments. The effect of BMP-2 on the proliferation, migration and invasion of osteosarcoma cells was tested in vitro. Subcutaneous and intratibial tumor models were used for the in vivo experiments in nude mice. The effects of BMP-2 on EMT of osteosarcoma cells and the Wnt/ß-catenin signaling pathway were also tested using a variety of biochemical methods. In vitro tests did not show a significant effect of BMP-2 on tumor cell proliferation. However, BMP-2 increased the mobility of tumor cells and the invasion assay demonstrated that BMP-2 promoted invasion of osteosarcoma cells in vitro. In vivo animal study showed that BMP-2 dramatically enhanced tumor growth. We also found that BMP-2 induced EMT of osteosarcoma cells. The expression levels of Axin2 and Dkk-1 were both down regulated by BMP-2 treatment, while ß-catenin, c-myc and Cyclin-D1 were all upregulated. The expression of Wnt3α and p-GSK-3ß were also significantly upregulated indicating that the Wnt/ß-catenin signaling pathway was activated during the EMT of osteosarcoma driven by BMP-2. From this study, we can conclude that BMP-2 significantly promotes growth of osteosarcoma cells (143B, MG63), and enhances mobility and invasiveness of tumor cells as demonstrated in vitro. The underlying mechanism might be that BMP-2 promotes EMT of osteosarcoma through the Wnt/ß-catenin signaling pathway. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1638-1648, 2019.

Subaxial cervical spine trauma classification: the Subaxial Injury Classification system and case examples.

Object The authors review a novel subaxial cervical trauma classification system and demonstrate its application through a series of cervical trauma cases. Methods The Spine Trauma Study Group collaborated to create the Subaxial Injury Classification (SLIC) and Severity score. The SLIC system is reviewed and is applied to 3 cases of subaxial cervical trauma. Results The SLIC system identifies 3 major injury characteristics to describe subaxial cervical injuries: injury morphology, discoligamentous complex integrity, and neurological status. Minor injury characteristics include injury level and osseous fractures. Each major characteristic is assigned a numerical score based upon injury severity. The sum of these scores constitutes the injury severity score. Conclusions By addressing both discoligamentous integrity and neurological status, the SLIC system may overcome major limitations of earlier classification systems. The system incorporates a number of critical clinical variables-including neurological status, absent in earlier systems-and is simple to apply and may provide both diagnostic and prognostic information.

Different Fusion Approaches for Single-level Lumbar Spondylolysis Have Similar Perioperative Outcomes.

STUDY DESIGN: Retrospective cohort study OBJECTIVE.: The aim of this study was to compare perioperative adverse events for patients with lumbar spondylolysis treated with transforaminal lumbar interbody fusion (TLIF), posterior spinal fusion (PSF), combined anterior and posterior fusion (AP fusion), or anterior lumbar interbody fusion (ALIF). SUMMARY OF BACKGROUND DATA: Previous cohort studies have shown similar long-term outcomes for different surgical approaches for this indication, but potential differences in 30-day perioperative adverse events have not been well characterized. METHODS: The present study uses data extracted from the American College of Surgeons National Surgical Quality Improvement Database. Patients undergoing fusion with different approaches for lumbar spondylolysis were identified. Propensity score matching was utilized to account for potential differences in demographic and comorbidity factors. Comparisons among perioperative outcomes were then made among the propensity score-matched study groups. RESULTS: Of 1077 cases of spondylolysis identified, 556 underwent TLIF, 327 underwent PSF, 108 underwent AP fusion, and 86 underwent ALIF. After propensity score matching, there were no differences in the rates of any of the 30-day individual adverse events studied and no differences in the aggregated groupings of any adverse event, serious adverse event, or minor adverse event. There was a significantly increased operative time in the AP fusion group, but there were no differences in hospital length of stay or readmission rates. CONCLUSION: Because perioperative adverse event rates were similar, even with a slightly longer operative time in the AP fusion group, these findings suggest that surgeon preference and long-term outcomes are better used to determine the recommendation of one surgical approach over another for single level fusions for lumbar spondylolysis. LEVEL OF EVIDENCE: 3.