bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biomechanical Evaluation of the Monoaxial Pedicle Screw and Plate Construct for Minimally Invasive Transforaminal Lumbar Interbody Fusion after Decompressive Surgery
Authors: Zhou Y. , Li J. , Zhu Q. , Li C. , Liu H. , Huang Z. , Shang J. 
Published: May 2014

Introduction Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is one popular posterior lumbar fusion surgery. The immediately biomechanical stability after unilateral or bilateral facetectomy of direct decompression is dependent on the type of supplement pedicle screw fixation used. The monoaxial pedicle screw and plate (PSP) has been approved for clinical use for added stabilization after cage instrumentation, especially for axial rotation stabilization. However, little biomechanical data exist comparing PSP fixation with bilateral multiaxial pedicle screw and rod (PSR) fixation. Materials and Methods Eight L3-L6 calf spines were instrumented with posterior cages at L4-L5 after intact kinematic analysis. The TLIF model was generated by clinical procedure and fixed with multiaxial PSR or monoaxial PSP by randomized sequence. A pure moment (±5.0 Nm) were applied to specimens to induce flexion/extension, lateral bending (LB) (left + right), and axial rotation (AR) (left + right) while recording intact versus instrumented range of motion (ROM). Two monoaxial strain gauges were instrumented at the surface of L4 and L5 vertebrae body each, to record the strain distribution under the flexion and lateral bending motion. Destructive tests of monoaxial PSR, multiaxial PSR, and monoaxial PSP construct were used to record the modes of failure, yield strength, and yield stiffness in a static compression bending test. Results Monoaxial PSP fixation significantly reduced ROM ( p < 0.001) at the lumbar level (flexion/extension: 88.7%; LB: 94.7%; AR: 53.8%) relative to the intact condition. Multiaxial PSR fixation afforded the similar ROM reductions ( p < 0.001) relative to the intact condition (flexion/extension: 83.1%; LB: 92.6%; AR: 42.3%). The strain distribution with monoaxial PSP fixation is not significantly larger than that with multiaxial PSR fixation when different loading conditions were applied (flexion vs. lateral bending). The strain distribution of L4 in both fixation conditions was significantly less than that in intact condition in lateral bending. The yield stiffness of the monoaxial PSP construct is significantly less than that of the monoaxial PSR construct ( p < 0.001), while the yield strength of the monoaxial PSP construct is significantly larger than that of the monoaxial PSR construct ( p < 0.001). Conclusion Based on these biomechanical findings, monoaxial PSP fixation and multiaxial PSR fixation are equal to afford the immediate stability after TLIF surgery. The property of low yield stiffness in monoaxial PSP construct has the potential to reduce the stress-shielding effect of the fusion segment. Disclosure of Interest None declared
Collagen-Targeting Parathyroid Hormone-Related Peptide Promotes Collagen Binding and in Vitro Chondrogenesis in Bone Marrow-Derived MSCs
Authors: Wu X. , Huang B. , Wang J. , Li C. , Zhou Y. 
Published: May 2014

Introduction Parathyroid hormone-related peptide (PTHrP) is an important inductive factor during chondrogenesis of mesenchymal stem cells (MSCs). PTHrP induces chondrogenesis and suppresses hypertrophy, yet the lack of an efficient delivery system limits its use for cartilage tissue engineering in clinical application. Materials and Methods In this study, a peptide of seven amino acids was first used to engineer PTHrP to construct a collagen-targeting system. This peptide functioned as a collagen-binding domain (CBD) to specially target the PTHrP to collagen. ELISA assay was used to determine the collagen-binding ability of CBD-PTHrP. The effect of CBD-PTHrP on chondrogenesis was measured by an in vitro pellet assay in bone marrow-derived MSCs (BM-MSCs). Results The CBD peptide promoted the binding of CBD-PTHrP to collagen when compared with NAT-PTHrP. Furthermore, the recombinant protein CBD-PTHrP induced the expression of COL2A1 and Sox-9, inhibited the expression of COL1A1 at the mRNA and protein levels as effectively as NAT-PTHrP. Safranin-O and immunohistochemistry for collagen types I, II, X and Sox-9 generally paralleled qRT-PCR and Western blotting findings with minor variations. Conclusion Our study demonstrated that CBD-PTHrP is a collagen-targeting system and promotes in vitro chondrogenesis in BM-MSCs. We suggest that this is an efficient delivery system for cartilage tissue engineering in clinical application. Disclosure of Interest None declared
Selective Decompression and Interlaminar Dynamic Stabilization for the Treatment of Degenerative Lumbar Stenosis: A Perspective of 3 to 5 Years Follow-up Evaluation
Authors: Hai Y. 
Published: May 2014

Introduction To evaluate the clinical efficacy and safety of posterior Coflex dynamic stabilization for the treatment of degenerative lumbar stenosis, a perspective clinical and radiographic study was conducted and 3 to 5 years outcome was reported. Materials and Methods Between September 2007 and August 2009, 48 consecutive patients with degenerative lumbar stenosis were prospectively enrolled and treated with selective decompression and Coflex interlaminar dynamic stabilization. There were 23 male and 25 female (age 60.3 years; range, 48-79). Forty-six patients underwent single-level procedure and two patients with two-level procedures. The outcome evaluations were using VAS scale, modified ODI score, and radiographic results with the ROM of surgery and adjacent level as well as complications. All data were analyzed and patient's satisfaction was evaluated at final follow-up examination. Results Follow-up examinations were conducted at 1, 3, 6, 12, 24, and 36 months postoperatively and clinical and radiographic evaluations were performed. All patients were followed up at least 36 months (36-60 months, average 45.2 months). The average VAS scale was 8.1 pre-op, 2.9 post-op, and 2.5 at latest follow-up. The ODI score was 54.3 pre-op, 21.8 post-op, and 24.5 at the latest follow-up. All data mentioned above were statistically significantly improved. During follow-up, the range of motions (ROM) of operated levels were maintained (2-6 degrees, average 3.6 degrees) and there was no significant increase of ROM in adjacent level. Seven cases of Coflex device-related complications (14.6%) were occurred, but no patient underwent revision surgery for it. Conclusion From this prospective study from single institute, mid- to long-term satisfactory clinical outcome could be achieved in patients with single level of DLS treated by selective decompression and posterior Coflex interlaminar dynamic stabilization, with few device-related complications and ASD occurred. Disclosure of Interest None declared
Comparison between Posterior Laminectomy and Discectomy Followed by Coflex and Transforaminal Lumbar Interbody Fusion in Treating Lumbar Disc Herniation: A Minimum 2-year Follow-up Study
Authors: Wang Z. , Luo Z. , Shangguan L. 
Published: May 2014

Introduction The aim of the study is to compare the clinical outcomes of posterior decompression combined with interlaminar dynamic reconstruction-Coflex or transforaminal lumbar interbody fusion in treating lumbar disc herniation with instability. Materials and Methods A comparative study was performed on 13 male and 31 female patients (L3/4 18, L4/5 26) diagnosed as lumbar disc herniation with instability, with an average age of 53.6 years (range, 39-73 years), of which all cases were followed up at least 2 years. All patients were treated with interlaminar dynamic fixation with Coflex system (Coflex group, 19 cases) or transforaminal lumbar interbody fusion (TLIF group, 25 cases). The results were assessed by medical cost, operation time, blood loss, and Oswestry disability index (ODI). The range of motion (ROM) and intervertebral height of index and adjacent segments and the Lordosis of lumbar spine were measured before operation and last follow-up. Results The medical cost operative time and blood loss were significantly decreased in Coflex group than those in TLIF group. At the last follow-up, the ODI of groups Coflex and TLIF were significantly improved when compared with the preoperative values ( p < 0.05). At last follow-up, a better range of motion and intervertebral height of index and adjacent segments were found in Coflex group. However, the reoperation rate of Coflex group was higher than that of TLIF group ( p < 0.05). Conclusion Posterior decompression combined with Coflex has the same midterm effectiveness as transforaminal lumbar interbody fusion in treating degenerative lumbar disc herniation with instability and Coflex has less traumatic and recovery time, somewhat protective effect on the adjacent segments. However, the rate of reoperation is slightly higher in Coflex Group. Disclosure of Interest None declared
Modified Plate-Only Open-Door Laminoplasty versus Laminectomy and Fusion for Treatment of Cervical Stenotic Myelopathy: A Comparative Analysis on Decompression and Complications
Authors: Yang L. 
Published: May 2014

Introduction In this study, we compared modified plate-only laminoplasty with laminotomy and fusion to confirm which of the two surgical modalities could achieve a better decompression outcome, and whether there was any significant difference in postoperative complications between the two techniques. Materials and Methods Clinical data of 141 patients with cervical stenotic myelopathy who underwent plate-only laminoplasty and laminectomy from November 2007 to June 2010 were reviewed retrospectively. The extent of decompression was assessed by measuring the cross-sectional area of the dural sac and the distance of spinal cord drift at 3 most narrowed levels on T2-weighed MRI. Clinical outcomes and complications were also recorded and compared. Results Significant enlargement of dural sac area and spinal cord drift was achieved and well maintained in both groups, while the extent of decompression was greater in patients who underwent laminectomy and fusion. However, a greater decompression extent did not seem to produce a better clinical outcome. No significant difference was observed in JOA scores and Nurick scores between the two groups. Patients who underwent plate-only laminoplasty showed a better improvement in NDI scores and VAS scores. In addition, limited decompression, rigid reconstruction of the spinal canal, preservation of cervical mobility together with preservation of the posterior structure resulted in a lower rate of postoperative C5 palsy and axial pain in modified laminoplasty group. Conclusion Modified laminoplasty may be a more viable option for patients with cervical stenotic myelopathy. Disclosure of Interest None declared
Moderately Degenerative Disc with Annular Rupture is a Source of Low Back Pain
Authors: Zheng Z. , Yang H. , Liu H. 
Published: May 2014

Introduction Difficulty remains in identification of the sources of low back pain (LBP) due to spinal degenerative disorders. Degenerative intervertebral disc (IVD) may contribute to pain generation. However, the relationship of disc degeneration and occurrence of LBP is still unclear, which makes it difficult to locate a surgical target for a discectomy and predict the clinical outcome. The purpose of the present study was to explore the characteristic changes of a painful disc in MRI and attempt to clarify the underlying role of inflammatory mediators and AF tears in disc degeneration and LBP occurrence. Materials and Methods Human disc specimens and MRI from 57 single segment IVD protrusion patients with radiculopathy were collected by discectomy. VAS of low back pain were recorded before and postsurgery for all patients. All patients were grouped according to the LBP occurrence or the disc degeneration Pfirrmann grades. Degenerated disc inflammatory mediators (IL-1β, TNF-α, iNOS, and substance P) expression were compared with immunohistochemical analysis and real-time polymerase chain reaction (RT-PCR) among different groups. The relationship of IVD degeneration severity, incidence of HIZ, and occurrence of LBP was investigated via MRI. Results RT-PCR and immunohistochemical analysis showed no significant differences in inflammatory mediators expression between the disc samples with and without LBP. Moderately degenerative IVD according to Pfirrmann grade demonstrated the highest inflammatory mediators expression compared with mildly and severely degenerative IVD. For LBP patients, the postoperative VAS of LBP was significantly decreased. The LBP occurrence in moderately degenerated patients was the highest (70.8%). The HIZ incidence was 75% in moderately degenerated patients, while 61.9% in severely degenerated patients. The patients who demonstrated both moderate disc degeneration and HIZ had 83.3% LBP occurrence, higher than the rest of the patient population. Conclusion Moderately degenerative disc with AF tear is a source of LBP. MRI showing moderately degenerative disc with HIZ could be an indication of discectomy and may predict good prognosis. Disclosure of Interest None declared
Different Sites of L5 Nerve Root Compression Cause Different Phenotypes of Sensory Deficit
Authors: Lin J. H. , Chiang Y. H. 
Published: May 2014

Introduction Identifying the pathology responsible for the clinically presenting symptoms and signs on the image of lumbar spine is critical for a success of lumbar spine surgery. A nerve root could be compressed within the spinal canal at its preganglion segment, dorsal root ganglion, or both, depending on the pathoanatomy, such as central disc herniation, lateral recess stenosis, or foraminal stenosis. The responsible pathology required to be decompressed has a high impact on the decision of surgical strategy. For a given L5 nerve compression by central disc herniation (L4/5), a simple discectomy is capable to relieve the compression, whereas total facetectomy followed by spinal fusion is required for foraminal stenosis. Sensory deficit in lumbar radiculopathy provides a useful information helping the surgeons identifying the corresponding pathology and planing the surgical strategy. This study is devoted to elucidate the role of the phenotype of sensory deficit in different sites of nerve root compression and to see if the phenotype of sensory deficit is able to predict the compression site on the images. Materials and Methods The study prospectively included patients who had degenerative spinal disorders on L4/5 or L5/S1 levels with/without L5 radicular pain. The compressing pathologies on L5 nerve root were divided into three categories: the disc level (L4/5), the pedicle level (L5), and the foremen level (L5/S1). The sensory examination included warm, cold, static mechanical, and dynamic mechanical sensation on the foot dorsum ipsilateral to the pathology, and the foot dorsum contralateral to the pathology on the images served as the control. The association between the sensory examination and the compression sites was analyzed. Results A total of 48 patients met the inclusion criteria. The incidences of compressing pathology were 52% (25/48) in the disc level, 43% (21/48) in the pedicle level, and 20% (10/48) in the foramen level. There were 54% (26/48) patients with impaired warm sensation, 45% (22/48) with impaired cold sensation, 27.78% (10/36) with impaired static mechanical stimuli, and 39.58% (19/48) with impaired dynamic mechanical stimuli. The sensory deficit in cold or warm was highly associated with the compressing pathology at the pedicle or foramen level ( p = 0.0023) with 78.5% sensitivity and 65% specificity. Conclusion Based on our results, different sites of L5 nerve root compression caused different phenotypes of sensory deficit. One should cautiously look for compressing pathology at pedicle/foramen level if the patient presents sensory deficit. Disclosure of Interest None declared
Basic Research on Neuronal Activation Induced by Intradiscal Pain Stimulation into Degenerative ?Intervertebral Disc Using Capsaicin
Authors: Orita S. , Nishiori H. , Yamauchi K. , Sakuma Y. , Kubota G. , Oikawa Y. , Inage K. , Sainoh T. , Sato J. , Fujimoto K. , Takahashi K. , Ohtori S. 
Published: May 2014

Introduction Previously, it was reported that pain perception is related to not only DRG but also to the reaction of the central nervous system; however, the reaction of the dominant nervous system to pain stimulus in the intervertebral discs is unknown. The purpose of this research was to verify the mechanism of reaction of the nervous system, which controls the intervertebral discs, using chemical pain stimulus. Materials and Methods We used 6-week-old Sprague Dawley rats, and injected 20 µL capsaicin solution, which contains 2% Fluoro-Gold (FG), into the L5/6 intervertebral disc. FG is an antidromic neuronal tracer. Seven days after injection, we prepared perfusion fixation of the rats and extracted DRGs from L1 to L6 along with the lumbar enlargement of spinal cord. At the DRG, we detected CGRP, which is a nociceptive pain-related protein, by immunostaining, and measured the distribution of the expression. At the lumbar enlargement of the spinal cord, we detected Iba1, which is a marker for pain stimulus-activated micro glia, and compared Iba 1 expression in the capsaicin group and vehicle group, in which we injected only 20 µL saline solution (each is n = 5). Results The rate of distribution of CGRP positive cells in the FG positive rats was highest at the L2 DRG, and the rate was higher in the capsaicin group (54.9%) than in vehicle group (27.1%), with a statistically significant difference ( p < 0.05). The number of Iba1 positive micro glia cells per 1.4 × 10 mm2 was also larger in the capsaicin group (31.7 cells) than in the vehicle group (14.8 cells), with a statically significant difference ( p < 0.05) Conclusion The results of this experiment suggested that the chemical stimulus to the L5/6 intervertebral disc resulted in an elevated CGRP expression that caused pain around the L2 DRG area, and the mechanism of pain perception is strongly related to the activation of microglia at the posterior horn of the spinal cord. Disclosure of Interest None declared
Unilateral Tubular Approach for Bilateral Laminectomy: Effect on Ipsilateral and Contralateral Buttock and Leg Pain
Authors: Alimi M. , Hofstetter C. P. , Torres J. M. , Cong G. T. , Njoku I. , Hartl R. 
Published: May 2014

Introduction Tubular laminectomy is an effective treatment for lumbar spinal stenosis (LSS) with neurogenic claudication and leg pain. Many surgeons agree that tubular approach results in a more complete decompression of the contralateral thecal sac and nerve root, as compared with the ipsilateral side. With this study, we sought to answer the question whether this is reflected in clinically significant differences between right- and left-sided postoperative leg pain. Materials and Methods First, all patients with LSS who underwent MIS laminectomy through tubular retractors between 2004 and 2011 were identified (110 patients). Among those, two groups of patients were included in the study: patients with equal preoperative leg VAS scores and paint s with unequal leg VAS scores. At the latest follow-up, in the equal pain group the extent of VAS score improvement on the approach side was compared with the extent of improvement on the contralateral side. Also, at the latest follow-up, in the unequal pain group, the extent of dominant side pain improvement was compared between the patients who were approached ipsilaterally to the painters who were approached contralaterally. Results In the equal pain group, at the latest follow-up of 25.8 ± 3.4 months, leg VAS scores were significantly improved both on the ipsilateral and the contralateral side compared with before surgery ( p < 0.001 and p = 0.001, respectively). In the unequal pain group, at the latest follow-up of 31.3 ± 3.7 months, leg VAS scores were significantly improved only on the contralateral side of the approach ( p < 0.001). In the equal pain group, there were no statistically significant differences between the extent of pain improvement on the ipsilateral and on the contralateral side. Conclusion Minimally invasive tubular laminectomy through a unilateral approach results in effective bilateral decompression. Disclosure of Interest None declared
Anatomy of Failure in Lumbar Disc Herniation. An in Vivo, Multimodal, Prospective Study of 181 Subjects
Authors: Rajasekaran S. , Bajaj Nipun , Tubaki Vijay , Kanna Rishi M. , Shetty Ajoy Prasad 
Published: May 2014

Study Design A prospective clinical study including radiological, serial postcontrast magnetic resonance imaging, intraoperative findings, and histopathological study. Objective The objective of this study is to document in vivo, the site of anatomical failure in lumbar disc herniation (LDH) in patients requiring disc excision surgery. Summary of Background Data In vitro mechanical disruption studies have demonstrated both the end plate junction (EPJ) and the annulus fibrosus (AF) as the site of failure in LDH depending upon the type of force used. However, corroborative studies in vivo to document the exact anatomy of failure have not been done in humans. Methods A total of 185 consecutive patients requiring microdiscectomy at a single level formed the study group. The status of the end plate and AF in the operated level (study discs) and the other discs (control) were evaluated by plain radiograph, thin slice computed tomographic scan, plain and contrast magnetic resonance imaging, intraoperative examination, and histopathological analysis. Results LDH due to EPJ failure (EPJF- type I herniation) was more common (117; 65%) than annulus fibrosis rupture. Herniated discs had a significantly higher incidence of EPJF than control discs ( p < 0.0001) The EPJF was evident radiologically as vertebral corner defect in 30 patients, rim avulsion in 46, frank bony avulsions in 24, and avulsion at both upper and lower EP in 4. Thirteen discs with normal EP radiologically had cartilage or bone avulsion intraoperatively. Sixty-four discs (35%) had intact EP of which annular high intensity zone was found in 21 (11%) suggesting a disruption of AF (type II herniation). Postcontrast magnetic resonance image of 20 patients showed dye leak at the EPJ proving EPJF as main cause of LDH. Conclusion Our study is the first in vivo evidence that LDH in humans is more commonly the result of EPJF than AF rupture in patients requiring disc surgery. Our results offer clinical validation of previous in vitro mechanical disruption studies. Future research must focus on the EPJ as a primary area of interest in LDH. Disclosure of Interest None declared
Transactivation of programmed ribosomal frameshifting by a viral protein
Authors: Li Yanhua , Treffers Emmely E. , Napthine Sawsan , Tas Ali , Zhu Longchao , Sun Zhi , Bell Susanne , Mark Brian L. , van Veelen Peter A. , van Hemert Martijn J. , Firth Andrew E. , Brierley Ian , Snijder Eric J. , Fang Ying 
Published: May 2014

Significance
Ribosomes synthesize proteins by translating mRNAs into linear chains of amino acids through the decoding of consecutive nucleotide triplets (codons). Specific mRNA signals, however, can stimulate ribosomes to shift into an alternative triplet reading frame (ribosomal frameshifting) resulting in translation of a different protein. Typically, such signals are regions of intramolecular nucleotide base-pairing in the mRNA which form structures that stall ribosome progress. Here we show that the frameshifting signal used to express the nsp2TF and nsp2N proteins of porcine reproductive and respiratory syndrome virus, an important swine pathogen, requires the action of a transacting viral protein rather than a structured RNA. This novel mechanism of gene expression may also be used by other viruses or in cellular gene expression.