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Study Design: In vitro biomechanical evaluation of a novel self-adaptive unidirectional ratchet growing rod (RGR) system., Objective: The aim of this study was to propose and biomechanically validate a novel RGR construct in vitro using porcine thoracic spines and calculate the tensile force required to elongate the RGR with springs, without springs, and with soft tissue encapsulation (induced in vivo in rabbits)., Summary of Background Data: Literature lacks clear consensus regarding the implant of choice for early-onset scoliosis. Multiple systems are currently available, and each has its own advantages and disadvantages. Therefore, studying novel designs that can credibly accommodate growth and curb deformity progression is of principle importance., Methods: In vitro biomechanical motion tests were done using six porcine thoracic spines with pedicle screws at T3 and T8. A pure moment of ±5 Nm was loaded in lateral bending (LB) and flexion-extension. Range of motion (ROM) and neutral zone (NZ) of each specimen was determined after connecting the free movable growing rods (FGRs), RGRs, and standard rods (SRs). Tensile tests were done to measure the force required to elongate the RGR with springs, without springs, and with soft tissue encapsulation (induced in vivo in rabbits)., Results: Global ROM, implanted T3-T8 ROM, and the NZ of specimens with FGRs and RGRs were significantly higher than that with SRs. The RGRs favored unidirectional elongation in both LB and flexion. The tensile forces required for elongating the RGR without springs, with springs, and with soft tissue capsulation (by a scaled unit of 3 mm) were 3 ± 1.3 N, 10.5 ± 0.4 N, and 48.4 ± 14.4 N, respectively., Conclusion: The RGR could stabilize and favor unidirectional elongation of the implanted spinal column when appropriate forces were present. There was no device failure as far as we have studied and it is anticipated that, with further safety and feasibility assessment, RGRs could be adapted for clinical use., Level of Evidence: N/A.

A bioactive calcium sulfate/glass composite was prepared using a sintering technique, and Ca-P-Si glass particles were prepared by spray pyrolysis. The glass exhibited bioactivity in terms of its ability to form apatite in a simulated body fluid. The glass was transformed into two crystallized phases, i.e., calcium phosphate and calcium silicate, respectively, during the heating stage. The presence of the crystallized phases retarded the densification of calcium sulfate. A high sintering temperature of 1200 °C was needed to prepare the composite. The increased addition of glass enhanced the strength and decreases the degradation rate of calcium sulfate. The new composite is not only degradable but also bioactive.

Background: The expression of both high-mobility group box 1 (HMGB1) and receptor for advanced glycation end-products (RAGE) is upregulated in degenerated discs. HMGB1 is known to function as a coupling factor between hypoxia and inflammation in arthritis, and this inflammatory response is modulated by microRNAs (miRNAs), with miR-107 expression downregulated during hypoxia. In this study, we investigated the regulation of the miR-107/HMGB1/RAGE pathway in degenerated nucleus pulposus cells (NPCs) after hyperbaric oxygen (HBO) treatment., Methods: NPCs were separated from human degenerated intervertebral disc tissues. The control cells were maintained in 5% CO 2 /95% air, and the hyperoxic cells were exposed to 100% O 2 at 2.5 atmospheres absolute. MiRNA expression profiling was performed via microarray and confirmed by real-time PCR, and miRNA target genes were identified using bioinformatics and luciferase reporter assays. The cellular protein and mRNA levels of HMGB1, RAGE, and inducible nitric oxide synthase (iNOS) were assessed, and the phosphorylation of MAPK (p38MAPK, ERK, and JNK) was evaluated. Additionally, cytosolic and nuclear fractions of the IκBα and NF-κB p65 proteins were analyzed, and secreted HMGB1 and metalloprotease (MMP) levels in the conditioned media were quantified., Results: Using microarray analyses, 96 miRNAs were identified as upregulated and 66 downregulated following HBO treatment. Based on these results, miR-107 was selected for further investigation. Bioinformatics analyses indicated that the 3' untranslated region of the HMGB1 mRNA contained the "seed-matched-sequence" for hsa-miR-107, which was validated via dual-luciferase reporter assays. MiR-107 was markedly induced by HBO, and simultaneous suppression of HMGB1 was observed in NPCs. Knockdown of miR-107 resulted in upregulation of HMGB1 expression in HBO-treated cells, and HBO treatment downregulated the mRNA and protein levels of HMGB1, RAGE, and iNOS and the secretion of HMGB1. In addition, HBO treatment upregulated the protein levels of cytosolic IκBα and decreased the nuclear translocation of NF-κB in NPCs. Moreover, HBO treatment downregulated the phosphorylation of p38MAPK, ERK, and JNK and significantly decreased the secretion of MMP-3, MMP-9, and MMP-13., Conclusions: HBO inhibits pathways related to HMGB1/RAGE signaling via upregulation of miR-107 expression in degenerated human NPCs.

Gene therapy for bone tissue engineering has been widely developed. Recently, non-viral DNA-based gene therapy has been reported to be a safer and more efficient method of delivering DNA into target cells. We used a non-viral gene transfection reagent to delivery bone morphogenetic protein-2 (BMP-2) gene into bone marrow stromal cells (BMSCs). Primary BMSCs were isolated from rat femurs and transfected with BMP-2 plasmids. The transfection rate was analyzed using flow cytometry. The concentration of BMP-2 protein was quantified using an enzyme-linked immunosorbent assay. Levels of osteopontin and osteocalcin were measured to evaluate osteogenic differentiation. In vivo, we designed a critical-size calvarial defect rat model to study new bone regeneration, using Matrigel as a scaffold to carry BMP-2-transfected bone marrow stromal cells into the defect site. New bone formation was assessed by micro-computed tomography, X-ray, immunohistochemical staining and histomophometry. The transfection rate after 72 h was 31.5%. The BMP-2 protein level as well as osteopontin and osteocalcin expressions were higher in the experimental group (transfected with BMP-2) than the control group (transfected with green fluorescent protein, GFP). The in vivo study suggested that bone healing occurred 12 weeks after scaffold implantation. In addition, BMP-2-transfected bone marrow stromal cells provided better osteogenic differentiation than primary bone marrow stromal cells. Our findings suggest that non-viral gene therapy may be useful in bone tissue engineering., Significance: The study has clinical implications for the wider use of BMP-2-transfected BMSCs for cell-based transplantation therapy in bone regeneration., (Copyright © 2018. Published by Elsevier B.V.)

Cr-Fe-C alloy deposits were successfully prepared on high-carbon tool steel in a Cr 3+ -based electroplating bath containing Fe 2+ ions and suitable complex agents. A Cr-based alloy deposit was obtained with an electroplating current density higher than 25 Adm -2 , and a Fe-based alloy deposit was obtained using a current density of 20 Adm -2 . Following electroplating, these alloy deposited specimens were annealed via rapid thermal annealing (RTA) at 500 °C for different periods up to 30 s. The experimental results show that Cr- and Fe-based alloy deposits could be significantly hardened after RTA at 500 °C for a few seconds. The maximum hardness was that of the Cr-Fe-C alloy deposit annealed at 500 °C for 10 s. The maximum hardness of 1205 Hv was detected from the annealed Cr-based alloy deposit prepared with 30 ASD. The hardening mechanism of annealed Cr- and Fe-based alloy deposits is attributed to the precipitation of C-related membranes. The hardness values of the annealed Cr- and Fe-based alloy deposits increase with the increasing degree of crystallization of the C-related membranes., Competing Interests: The authors declare no conflict of interest.

Treating thoracic infective spondylodiscitis with anterior surgical approaches carry a relatively high risk of perioperative and postoperative complications. Posterior approaches have been reported to result in lower complication rates than anterior procedures, but more evidence is needed to demonstrate the safety and efficacy of 1-stage posterior approaches for treating infectious thoracic spondylodiscitis.Preoperative and postoperative clinical data, of 18 patients who underwent 2 types of 1-stage posterior procedures, costotransversectomy and transforaminal thoracic interbody debridement and fusion and 7 patients who underwent anterior debridement and reconstruction with posterior instrumentation, were retrospectively assessed.The clinical outcomes of patients treated with 1-stage posterior approaches were generally good, with good infection control, back pain relief, kyphotic angle correction, and either partial or solid union for fusion status. Furthermore, they achieved shorter surgical time, fewer postoperative complications, and shorter hospital stay than the patients underwent anterior debridement with posterior instrumentation.The results suggested that treating thoracic spondylodiscitis with a single-stage posterior approach might prevent postoperative complications and avoid respiratory problems associated with anterior approaches. Single-stage posterior approaches would be recommended for thoracic spine infection, especially for patients with medical comorbidities.

Background: Burst fracture is a common thoracolumbar injury that is treated using posterior pedicle instrumentation and fusion combined with transpedicular intracorporeal grafting after reduction. In this study, we compared the outcome of these two techniques by using radiologic imaging and functional outcome., Methods: Sixty-one patients with acute thoracolumbar burst fracture were operated with kyphoplasty (n = 31) or vertebroplasty (n = 30) and retrospectively reviewed in our institution between 2011 and 2014. All 61 patients underwent surgery within 5 days after admission to the hospital and then followed-up for 12 to 24 months after surgery., Results: Significant improvement was found in the anterior vertebral height (92 ± 8.9% in the kyphoplasty group, 85.6 ± 7.2% in the vertebroplasty group, p < 0.01) at 1 month post-operatively and (89 ± 7.9% in the kyphoplasty group, 78 ± 6.9% in the vertebroplasty group, p < 0.01) at the 24-month follow-up. Significant improvement was also observed in the kyphotic angle (1.2 ± 0.5° in the kyphoplasty group, 10.5 ± 1.2° in the vertebroplasty group, p < 0.01) at 1 month post-operatively and (5.4 ± 1.2° in the kyphoplasty group, 11.5 ± 8.5° in the vertebroplasty group, p < 0.01) at the 24-month follow-up. Both operations led to significant improvement of the patients' pain and the Oswestry disability index (p < 0.01). Cement leakage was noted in 29% of patients after kyphoplasty and 77% of patients after vertebroplasty (p < 0.01). Only one implant failure (3.3%), which required further surgical intervention, was reported in the vertebroplasty group., Conclusions: Reduction with additional balloon at the fractured site is better than indirect reduction only by posterior instrumentation. The better reduction of kyphotic angle and the lower cement leakage rate in the kyphoplasty group indicate that additional balloon kyphoplasty is safe and effective for acute thoracolumbar burst fracture.

Background: To investigate the role of vertebral augmentation in kyphosis reduction, vertebral fracture union, and correction loss after surgical management of thoracolumbar burst fracture., Design: Retrospective chart and radiographic review., Setting: Level 1 trauma center., Methods: The analysis included patients treated between April 2007 and June 2015, who received pedicle-screw-rod distraction and reduction within two days following acute traumatic thoracolumbar burst fracture with a load sharing score >6. Medical records were retrospectively reviewed for data regarding operative details, imaging and laboratory findings, neurological function, and functional outcomes., Intervention: Not applicable., Main Outcome Measures: Sagittal index, pain score, loss of correction, and implant failure rate., Results: Nineteen patients were enrolled in this study (mean age, 37.2±13years; age range, 17-62 years; female/male ratio: 10/9). Of the five patients who received only reduction (no augmentation), one underwent revision surgery because of implant failure and pedicle screw backing out. Compared to patients who received only reduction, those who received both reduction and augmentation showed better sagittal alignment after the operation, with better sagittal index immediately postoperatively and during the follow-up (p<0.05)., Conclusions: Transpedicular vertebral augmentation with calcium sulfate/phosphate-based bone cement may reinforce thoracolumbar burst fracture stability, partially restore vertebral body height, and reduce pedicle screw bending and movement, thereby preventing early implant failure and late loss of correction, especially in patients with excellent fracture reduction., Level of Evidence: Therapeutic level III, retrospective chart review., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background Context: The posterior pedicle screw-rod system, which is widely used to correct spinal deformities, achieves a good correction rate in the frontal and coronal planes but not in the axial plane. Direct vertebral derotation (DVD) was developed to correct axial plane deformities. However, the design of screw head and body connection, in terms of monoaxial, polyaxial, and uniplanar screw, may influence the efficiency of DVD., Purpose: This study compared the efficiency of a newly designed uniplanar screw with that of monoaxial and polyaxial screws in the DVD maneuver., Study Design: A porcine spine model and monoaxial, polyaxial, and uniplanar screws were used to examine the biomechanics of the DVD maneuver., Methods: Six T7-T13 porcine thoracic spine segments were used as test specimens in this study. Pedicle screws were inserted in the left pedicles of the T9-T11 spinal segments and then connected with a rod. Three types of pedicle screws with different screw head designs (monoaxial, polyaxial, and uniplanar) were employed in this study. The material testing system (MTS) machine generated a rotational moment through the derotational tube on the T10 (apical body) pedicle screw, which simulated the motion applied during the surgical vertebral derotational procedure. The pedicle strain and the kinematics of the vertebral body and derotational tube were recorded to evaluate the derotational efficiency of different pedicle screw head designs., Results: The variances of the derotation for the monoaxial, polyaxial, and uniplanar screws were 2.22°±1.43°, 32.23°±2.26°, and 4.75°±1.60°, respectively; the derotation efficiency was 0.65, 0.51, and 0.12, respectively, when the torques of the spinal constructs reached 3 Nm. The rotational variance of the polyaxial screw was statistically greater than that of the monoaxial and uniplanar screws (p<.05). The maximum micro-strains of the pedicles for the monoaxial, polyaxial, and uniplanar screws were 1,067.45±550.35, 747.68±393.56, and 663.55±271.04, respectively, with no statistically significant differences (p>.05)., Conclusions: The screw head design played an important role in the efficiency and variance of the derotation during the DVD maneuver. The derotational efficiency of the newly designed uniplanar screw was closer to that of the monoaxial screw group than to that of the polyaxial screw group. The polyaxial screw was inferior to DVD owing to a derotational variance between the derotational tube and the apical body that was correlated with the range of motion of the screw head. In the present study, the pedicle strain was similar in all groups. However, the pedicle strain of the uniplanar screw group was lower than that of the monoaxial screw group and was similar to that of the polyaxial screw group when the angle of rotation of the apical body increased., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Subjective visual vertical (SVV) judgment and standing stability were separately investigated among patients with adolescent idiopathic scoliosis (AIS). Although, one study has investigated the central mechanism of stability control in the AIS population, the relationships between SVV, decreased standing stability, and AIS have never been investigated. Through event-related potentials (ERPs), the present study examined the effect of postural control demands (PDs) on AIS central mechanisms related to SVV judgment and standing stability to elucidate the time-serial stability control process. Thirteen AIS subjects (AIS group) and 13 age-matched adolescents (control group) aged 12-18 years were recruited. Each subject had to complete an SVV task (i.e., the modified rod-and-frame [mRAF] test) as a stimulus, with online electroencephalogram recording being performed in the following three standing postures: feet shoulder-width apart standing, feet together standing, and tandem standing. The behavioral performance in terms of postural stability (center of pressure excursion), SVV (accuracy and reaction time), and mRAF-locked ERPs (mean amplitude and peak latency of the P1, N1, and P2 components) was then compared between the AIS and control groups. In the behavioral domain, the results revealed that only the AIS group demonstrated a significantly accelerated SVV reaction time as the PDs increased. In the cerebral domain, significantly larger P2 mean amplitudes were observed during both feet shoulder-width-apart standing and feet together standing postures compared with during tandem standing. No group differences were noted in the cerebral domain. The results indicated that (1) during the dual-task paradigm, a differential behavioral strategy of accelerated SVV reaction time was observed in the AIS group only when the PDs increased and (2) the decrease in P2 mean amplitudes with the increase in the PD levels might be direct evidence of the competition for central processing attentional resources under the dual-task postural control paradigm.

Surgical management of severe rigid dystrophic neurofibromatosis (NF) scoliosis is technically demanding and produces varying results. In the current study, we reviewed 9 patients who were treated with combined anterior and posterior fusion using different types of instrumentation (i.e., pedicle screw, hybrid, and all-hook constructs) at our institute.Between September 2001 and July 2010 at our institute, 9 patients received anterior release/fusion and posterior fusion with different types of instrumentation, including a pedicle screw construct (n = 5), a hybrid construct (n = 3), and an all-hook construct (n = 1). We compared the pedicle screw group with the hybrid group to analyze differences in preoperative curve angle, immediate postoperative curve reduction, and latest follow-up curve angle.The mean follow-up period was 9.5 ± 2.9 years. The average age at surgery was 10.3 ± 3.9 years. The average preoperative scoliosis curve was 61.3 ± 13.8°, and the average preoperative kyphosis curve was 39.8 ± 19.7°. The average postoperative scoliosis and kyphosis curves were 29.7 ± 10.7° and 21.0 ± 13.5°, respectively. The most recent follow-up scoliosis and kyphosis curves were 43.4 ± 17.3° and 29.4 ± 18.9°, respectively. There was no significant difference in the correction angle (either coronal or sagittal), and there was no significant difference in the loss of sagittal correction between the pedicle screw construct group and the hybrid construct group. However, the patients who received pedicle screw constructs had significantly less loss of coronal correction (P < .05). Two patients with posterior instrumentation, one with an all-hook construct and the other with a hybrid construct, required surgical revision because of progression of deformity.It is difficult to intraoperatively correct dystrophic deformity and to maintain this correction after surgery. Combined anterior release/fusion and posterior fusion using either a pedicle screw construct or a hybrid construct provide similar curve corrections both sagittally and coronally. After long-term follow-up, sagittal correction was maintained with both constructs. However, patients treated with posterior instrumentation using pedicle screw constructs had significantly less loss of coronal correction.

Background: The foremost concern of a surgeon during pedicle screw fixation is safety. Assistive modalities, especially intraoperative electromyographic monitoring (EMG) can function as an essential tool to recognize screw malposition that compromise neural integrity, so that the screws can be repositioned immediately rather than later. We intend to study the efficacy of intraoperative EMG monitoring to detect potential pedicle breach and evaluate whether reoperation rates were significantly reduced., Methods: Retrospectively, patients who underwent posterior stabilization with pedicle screws for various pathologies were analysed and those with screws among L1-S1 levels were shortlisted. They were divided into two groups. Group 1 included patients in whom trigger EMG (t-EMG) was used to confirm appropriate screw placement and Group 2 included those in whom it was not used. Responses to t-EMG and corresponding stimulation thresholds were recorded for Group 1 patients. The sensitivity and specificity of the test was calculated. Reoperation rates due to postoperative neurologic compromise caused by malpositioned screws were compared between both the groups., Results: A total of 518 patients had 3112 pedicle screws between L1-S1 levels. Among Group 1 [n = 296; Screws = 1856], 145 screws (7.8%) showed a positive response for t-EMG at stimulation thresholds ranging between 2.6 to 19.8 mA. The sensitivity and specificity of t-EMG to diagnose potential pedicle breach was found to be 93.33% and 92.88% respectively. Only one patient among Group 1 required reoperation. However, among Group 2 [n = 222; screws = 1256], six patients required reoperation. This indicated a significant decrease in the number of malpositioned screws that caused neurological compromise [p = 0.02], leading to subsequent decrease in reoperation rates [p = 0.04] among Group 1 patients., Conclusions: Trigger EMG is well efficient in detecting potential pedicle screw breaches that might endanger neural integrity. In combination with palpatory and radiographic assessment, it will certainly aid safe and secure pedicle screw placement. It can also efficiently reduce reoperation rates due to neurologic compromise provoked by a malpositioned screw.

Background: Pyogenic spondylodiscitis is a form of spinal infection that can result in severe back pain and even death. However, information is lacking on the relative effectiveness of various therapies. A retrospective chart review was conducted to investigate whether early surgical treatment of pyogenic spondylodiscitis coupled with intravenous antibiotics results in better patient prognoses than intravenous antibiotics therapy alone., Methods: All patients treated for pyogenic spondylodiscitis at a single medical center from July 2006 to July 2011 were retrospectively reviewed. The inclusion criteria consisted of diagnosis of an early stage infection without neurological deficit, and patients without severe sepsis who were suitable candidates for early surgery as determined by a Pittsburgh bacteremia score < 4, and patients with delayed diagnosis and lost to outpatient follow-up were excluded. Clinical outcomes included patient demographic data, kyphosis angle, length of treatment, Oswestry Disability Index and visual analogue pain scale were analyzed., Results: Of 90 enrolled patients, Group 1 (n = 47) received only antibiotic therapy and Group 2 (n = 43) received early surgery with post-surgery antibiotics for 2 to 4 weeks. Group 2 exhibited significantly better results than Group 1 for mean antibiotic administration period, mean hospitalization period, kyphotic angle correction. Of 61 patients who participated in telephone follow-up after discharge, Group 2 (n = 26) had significant lower mean ODI score, and mean back pain score than Group 1 (n = 35)., Conclusions: While infection control was similar for both groups, patients treated with early surgery and antibiotics were hospitalized for fewer days and required less antibiotics than those treated with antibiotics alone, also having better functional outcomes. In short, early surgical treatment of pyogenic spondylodiscitis typically achieves a better prognosis, shorter hospitalization period, and subsequent significant improvement in kyphotic deformity and quality of life.

Background: The aim of this study was to develop a minimally invasive hydrogel system that can release strontium ions, an element that has been shown to increase osteoblast proliferation and prohibit bone resorption, in a controlled manner., Methods: SrCO3 was selected as the salt of choice due to potential acid neutralization reaction between SrCO3 and degradation by-products of methoxy(polyethylene glycol)-co-poly(lactic-co-glycolic acid) (mPEG-PLGA): namely, lactic acid and glycolic acid. SrCO3 was incorporated into mPEG-PLGA hydrogel, and the system was assessed for gelation properties, drug release and biocompatibility., Results: SrCO3 incorporation at hydrogel to SrCO3 ratios of 5:1, 3:1 and 1:1 (wt%) did not compromise the thermosensitivity of mPEG-PLGA hydrogels. Furthermore, incorporation of SrCO3 at 1:1 ratio prevented copolymer self-catalysis and decreased hydrogel weight loss from 85% to 61% in vitro after 30 days. During the 30-day time frame, zero-order strontium release was observed and was correlated to hydrogel degradation and acidity. The addition of SrCO3 also improved in vivo hydrogel biocompatibility, due to moderation of acidic microenvironment and amelioration of inflammatory response., Conclusions: These results showed that the described system is suitable for the extended release of strontium and exhibits potential for localized treatment for osteoporosis or as a bone void filler.

Background: Wnt signaling plays an important role in development and maintenance of many organs and tissues. The most-studied secreted Wnt inhibitors are sclerostin (SOST), Dickkopf-related protein 1 (DKK-1), and secreted frizzled related protein 1 (SFRP-1) which play important roles in bone turnover. The present study investigated the relationship between serum Wnt inhibitors and diseases with excessive ossification structures, such as ossification of posterior longitudinal ligament (OPLL), ankylosing spondylitis (AS), diffuse idiopathic skeletal hyperostosis (DISH), and ossification of yellow ligament (OYL)., Methods: Twenty-five patients with AS, DISH, OPLL, or OYL were recruited in this study. Fasting peripheral blood samples were collected from all patients and nine controls. Various biomarkers of bone turnover including osteocalcin (OSC), osteoprotegerin (OPG), SFRP-1, DKK-1, and SOST were investigated., Results: Our data showed that serum levels of OSC were higher, but Dkk-1 levels were lower in AS, DISH, OPLL, and OYL patients than those in the controls. Serum levels of SFRP-1 were significantly higher in DISH patients than those in the controls. Serum levels of SOST were significantly higher in DISH and OPLL patients than both levels in the controls. Serum levels of OPG were lower in AS patients than those in the controls. Serum levels of OSC were higher in the OPLL patients than those in the AS patients. Serum levels of DKK-1, SFRP-1, SOST, and OPG were not significantly different between the different disease groups., Conclusions: In this exploratory study, both OSC and DKK-1 levels are correlated with the clinical conditions associated with excessive ossification, indicating that blood OSC and DKK-1 levels may serve as diagnostic biomarkers for AS, DISH, OPLL, and OYL. These findings may also help discover potential drug therapies for management of these diseases in the future.

Background: Of the proposed animal interbody fusion models, rat caudal discs have gained popularity in disc research due to their strong resemblance to human discs with respect to geometry, composition and mechanical properties. The purpose of this study is to demonstrate an efficient, repeatable and easily accessible animal model of interbody fusion for future research into mechanical testing and graft materials., Methods: Twelve 12-week-old female Sprague-Dawley (SD) rats underwent caudal interbody fusion of the third and fourth coccygeal vertebrae of the tail. Serial radiological evaluation, and histological evaluation and manual palpation after sacrifice were performed to assess the fusion quality. Mechanical testing of functional units (FUs) of non-operated and operated segments was compared using a three-point bending test., Results: At postoperative 12 weeks, callus formation was observed at the fusion sites in all rats, with the mean radiological evaluations of 2.75/3 according to the Bransford classification. Newly formed bone tissue was also observed in all rats with the mean histological score of 5.85/7, according to the Emery grading system. No palpable gaps and obvious change of bending stiffness was observed in the operated segments. The mean bending stiffness of the FUs was statistically higher than that of the control FUs (26.57 ± 6.71 N/mm vs. 12.45 ± 3.21 N/mm, p < 0.01)., Conclusion: The rat caudal disc interbody fusion model proved to be an efficient, repeatable and easily accessible model. Future research into adjuvant treatments like growth factor injection and alternative fusion materials under conditions of osteoporosis using this model would be worthwhile., (Copyright © 2017 Chang Gung University. Published by Elsevier B.V. All rights reserved.)

Elderly patients with chronic nonresolving symptoms due to degenerative spine pathologies are prone to have poor surgical outcomes and hardware-related complications, especially following multilevel instrumented lumbar fusion surgeries. With intention of analyzing if teriparatide can be an effective adjunct therapy to surgical management, radiological outcomes are studied. Sixty-two elderly patients were divided into 2 similar groups. Group 1 (n = 30; mean age = 69.83 years; fusion levels = 137; screws = 269) had taken teriparatide (20 mcg SC injection, once daily) for a duration of 7.4 ± 2.4 months following surgery and Group 2 (n = 32; mean age = 70.38 years; fusion levels = 144; screws = 283) did not take teriparatide. Radiological evaluation was done to determine the state of postero lateral fusion mass and to investigate the incidence of pedicle screw loosening at 1-year follow-up. Unilateral or bilateral bridging bone formation across the transverse process of adjacent vertebras showing continuous trabeculation suggestive of solid fusion was obtained in 66.7% patients in the teriparatide group and 50% patients in the control group (P = 0.20). 13.4% of the total no. of screws showed signs of loosening in the teriparatide group, compared to 24.4% in the control group (P = 0.001). Percentage of patients achieving solid fusion following teriparatide use was found to be more than that of the control group. This difference may have clinical importance but was not statistically significant. However, teriparatide use was more significantly influential in reducing the incidence of subsequent pedicle screw loosening., Competing Interests: The authors have no funding and conflicts of interest to disclose.

Osteoporosis is a bone disease that afflicts millions of people around the world, and a variety of spinal integrity issues, such as degenerative spinal stenosis and spondylolisthesis, are frequently concomitant with osteoporosis and are sometimes treated with spinal interbody fusion surgery. Previous studies have demonstrated the efficacy of strontium ranelate (SrR) treatment of osteoporosis in improving bone strength, promoting bone remodeling, and reducing the risk of fractures, but its effects on interbody fusion surgery have not been adequately investigated. SrR-treated rats subjected to interbody fusion surgery exhibited significantly higher lumbar vertebral bone mineral density after 12 weeks of treatment than rats subjected to the same surgery but not treated with SrR. Furthermore, histological and radiographic assessments showed that a greater amount of newly formed bone tissue was present and that better fusion union occurred in the SrR-treated rats than in the untreated rats. Taken together, these results show significant differences in bone mineral density, PINP level, histological score, SrR content and mechanical testing, which demonstrate a relatively moderate effect of SrR treatment on bone strength and remodeling in the specific context of recovery after an interbody fusion surgery, and suggest the potential of SrR treatment as an effective adjunct to spinal interbody fusion surgery for human patients., Competing Interests: The authors have declared that no competing interests exist.

Here, we discuss the development of a paper-based diagnostic device that is inexpensive, portable, easy-to-use, robust, and capable of running simultaneous tests to monitor a relevant inflammatory protein for clinical diagnoses i.e. C-reactive protein (CRP). In this study, we first attempted to make a paper-based diagnostic device via the wax printing method, a process that was used in previous studies. This device has two distinct advantages: 1) reduced manufacturing and assay costs and operation duration via using wax printing method to define hydrophobic boundaries (for fluidic devices or general POC devices); and, 2) the hydrophilicity of filter paper, which is used to purify and chromatographically correct interference caused by whole blood components with a tiny amount of blood sample (only 5 μL). Diagnosis was based on serum stain length retained inside the paper channels of our device. This is a balanced function between surface tension and chromatographic force following immune reactions (CRP assays) with a paper-embedded biomarker.

Bone tissue engineering provides many advantages for repairing skeletal defects. Although many different kinds of biomaterials have been used for bone tissue engineering, safety issues must be considered when using them in a clinical setting. In this study, we examined the effects of using a common clinical item, a hemostatic gelatin sponge, as a scaffold for bone tissue engineering. The use of such a clinically acceptable item may hasten the translational lag from laboratory to clinical studies. We performed both degradation and biocompatibility studies on the hemostatic gelatin sponge, and cultured preosteoblasts within the sponge scaffold to demonstrate its osteogenic differentiation potential. In degradation assays, the gelatin sponge demonstrated good stability after being immersed in PBS for 8 weeks (losing only about 10% of its net weight and about 54% decrease of mechanical strength), but pepsin and collagenases readily biodegraded it. The gelatin sponge demonstrated good biocompatibility to preosteoblasts as demonstrated by MTT assay, confocal microscopy, and scanning electron microscopy. Furthermore, osteogenic differentiation and the migration of preosteoblasts, elevated alkaline phosphatase activity, and in vitro mineralization were observed within the scaffold structure. Each of these results indicates that the hemostatic gelatin sponge is a suitable scaffold for bone tissue engineering.

Background: Spinous process has been routinely resected during posterior fusion of adolescent idiopathic scoliosis for fusion bed preparation and local autologous bone graft supplement. However, spinous process serves as an important structure in posterior ligament complex and was the anchorage of paraspinal muscle groups. With the development of pedicle screws instrumentation and the potential fusion ability in children, the need for resecting spinous process in this procedure could be further investigated. The purpose of this study was to compare the fusion rates, surgical outcomes and complications between harvesting and preserving the spinous process in posterior fusion of adolescent idiopathic scoliosis., Methods: From January 2003 to December 2008, 104 consecutive adolescent idiopathic scoliosis patients underwent primary posterior fusion with local autologous bone grafts and following for a minimum of 24 months were reviewed. The patients were divided into a harvesting group (n = 61) with the spinous process harvested, and a preserving group (n = 43) with the spinous process preserved. Blood loss, radiographic assessments, and clinical outcomes were compared between the two groups., Results: There were no significant differences in duration of surgery and peri-operative blood transfusion between the two groups. However, blood loss was statistically greater (983 ± 446 ml vs. 824 ± 361 ml; p = 0.048) and duration of hospitalization was statistically longer (7.4 ± 1.0 days vs. 6.8 ± 0.8 days; p = 0.003) in the harvesting group. The pre- and post-operative structural curves, correction rates, sagittal profile and loss of corrections were similar in both groups. Based on radiographic evaluation, the incidences of pseudoarthrosis were similar in both groups (3/61 vs. 2/43; p = 0.95). The incidence of prescribing pain medication for back discomfort during follow-up was statistically higher in the harvesting group (16/61 vs. 4/43; p = 0.03)., Conclusions: The surgical outcomes and fusion rates between harvesting and preserving the spinous process were comparable. Resecting the spinous process as local autologous bone graft may not be necessary in posterior fusion for adolescent idiopathic scoliosis patients.

Objective The incidence of bone fractures rapidly increases as people age, mostly due to bone loss resulting from osteoporosis. The purpose of this study is to compare the rates of repeat vertebroplasty in osteoporotic patients treated with or without zoledronic acid (ZOL) infusion following initial vertebroplasty. Research design and methods We conducted a retrospective chart review of osteoporotic patients who underwent vertebroplasty from June 2009 to June 2012. Patients with existing vertebral fracture(s) were retrospectively divided into two groups according to whether or not they received zoledronic acid infusion after initial vertebroplasty. Zoledronic acid infusion was intravenously administered once a year for three consecutive years, as a single 5 mg dose in 100 mL solution infused over at least 15 minutes. The primary efficacy variable was the number of patients requiring repeat vertebroplasty procedures after the initial surgery due to subsequent vertebral fractures. The Cox proportional hazards model was used to compare the risk ratios of repeat vertebroplasty between these two groups. Results A total of 1646 patients, including 456 males and 1190 females (age range: 65-89 years), were enrolled. Compared to the 1595 patients who did not receive osteoporosis medication, the 51 patients treated with zoledronic acid infusion demonstrated a significantly lower rate of repeat vertebroplasty. In the ZOL-treated group, only 4% of the patients (2/51) required a second vertebroplasty, compared to 13% (206/1595) in the non-ZOL-treated group (p = 0.032). Conclusions The results indicate that osteoporotic patients who undergo vertebroplasty are significantly less likely to require reoperation if treated with zoledronic acid infusion. However, since the number of male patients in the ZOL-treated group was limited, and since Taiwan's National Health System program does not cover the cost of receiving zoledronic acid infusions for male patients, the conclusion seems to be less certain for male osteoporotic patients.

Background: The need for revision surgery after a spinal surgery can cause a variety of problems, including reduced quality of life for the patient, additional medical expenses, and patient-physician conflicts. The purpose of this study was to evaluate the causes of unplanned revision spinal surgery within a week after the initial surgery in order to identify the surgical issues most commonly associated with unplanned revision surgery., Methods: We retrospectively reviewed the medical records of all patients at who received a spinal surgery at a regional medical center from July 2004 to April 2011 in order to identify those who required a revision surgery within one week of their initial surgery. Patients were excluded if they received a vertebroplasty, kyphoplasty, or nerve block surgery, because those surgeries are one-day surgeries that do not require hospital admission. In addition, patients with a primary diagnosis of wound infection were also excluded since reoperations for infection control can be expected., Results: The overall incidence of unplanned revision spinal surgery during the time period covered by this review was 1.12% (116/10,350 patients). The most common surgical causes of reoperation were screw malposition (41 patients), symptomatic epidural hematoma (27 patients), and inadequate decompression (37 patients). Screw malposition was the most common complication, with an incidence rate of 0.82%. Screw instrumentation was significantly associated with revision surgery (p = 0.023), which suggests that this procedure carried a greater risk of requiring revision. The mean time interval to reoperation for epidural hematomas was significantly shorter than the intervals for other causes of revision spinal surgery (p < 0.001), which suggests that epidural hematoma was more emergent than other complications. Also, 25.93% of patients who underwent hematoma removal experienced residual sequelae; this percentage was significantly higher than for other surgical causes of revision spinal surgery (p = 0.013)., Conclusions: The results suggest that to avoid the need for reoperation, screw malposition, inadequate decompression, and epidural hematoma are the key surgical complications to be guarded against. Accordingly, adequate decompression, epidural hematoma prevention, and proper pedicle screw placement may help reduce the incidence of revision surgery.

Polymethylmethacrylate (PMMA) bone cement is a popular bone void filler for vertebroplasty. However, the use of PMMA has some drawbacks, including the material's excessive stiffness, exothermic polymerization, and short handling time. This study aimed to create an ideal modified bone cement to solve the above-mentioned problems. Modified bone cements were prepared by combining PMMA with three different volume fractions of castor oil (5%, 10%, and 15%). The peak polymerization temperatures, times to achieve the peak polymerization temperature, porosities, densities, modulus and maximum compression strengths of standard (without castor oil), and modified cements were investigated following storage at ambient temperature (22°C) or under precooling conditions (3°C). Six specimens were tested in each group of the aforementioned parameters. Increasing castor oil content and precooling treatment effectively decreased the peak polymerization temperatures and increased the duration to achieve the peak polymerization temperature ( P < 0.05). Furthermore, the mechanical properties of the material, including density, modulus, and maximum compression strength, decreased with increasing castor oil content. However, preparation temperature (room temperature versus precooling) had no significant effect ( P > 0.05) on these mechanical properties. In conclusion, the addition of castor oil to PMMA followed by precooling created an ideal modified bone cement with a low modulus, low polymerization temperature, and long handling time, enhancing its applicability and safety for vertebroplasty.

Expansive pedicle screws significantly improve fixation strength in osteoporotic spines. However, the previous literature does not adequately address the effects of the number of lengthwise slits and the extent of screw expansion on the strength of the bone/screw interface when expansive screws are used with or without cement augmentation. Herein, four designs for expansive pedicle screws with different numbers of lengthwise slits and different screw expansion levels were evaluated. Synthetic bones simulating severe osteoporosis were used to provide a comparative platform for each screw design. The prepared specimens were then tested for axial pullout failure. Regardless of screw design, screws with cement augmentation demonstrated significantly higher pullout strength than pedicle screws without cement augmentation (p < 0.001). For screws without cement augmentation, solid screws exhibited the lowest pullout strength compared to the four expansive groups (p < 0.01). No significant differences in pullout strength were observed between the expansive screws with different designs (p > 0.05). Taken together, our results show that pedicle screws combined with cement augmentation may greatly increase screw fixation regardless of screws with or without expansion. An increase in both the number of slits and the extent of screw expansion had little impact on the screw-anchoring strength. Cement augmentation is the most influential factor for improving screw pullout strength.

Background Context: Mesenchymal stem cell (MSC)-based cell therapy and gene transfer have converged and show great potential for accelerating bone healing. Gene therapy can provide more sustained expression of osteogenic factors such as bone morphogenetic protein-2 (BMP-2). We previously demonstrated that low-dose BMP-2 enhanced spinal posterolateral fusion by MSCs in a rabbit model. Herein, we genetically modified rabbit MSCs with a recombinant baculovirus encoding BMP-2 (Bac-CB) and vascular endothelial growth factor (Bac-VEGF) seeded into porous scaffolds to enhance spinal fusion., Purpose: This study evaluates the success rate of the MSC-based cell therapy and gene transfer approach for single-level posterolateral spine fusion. We hypothesize that combining three-dimensional tricalcium phosphate (TCP) scaffolds and genetically modified allogeneic MSCs with baculovirus-mediated growth factor expression would increase the success rate of spinal fusion., Study Design: The study design was based on an animal model (approved by the Institutional Animal Care and Use Committee) using 18 adult male New Zealand rabbits., Methods: This study included 18 male New Zealand rabbits, weighing 3.5 to 4 kg. Allogeneic bone marrow-derived MSCs were isolated and genetically modified with Bac-CB and Bac-CV seeded onto TCP scaffolds (MSC/Bac/TCP). The animals were divided into three groups according to the material implanted into the bilateral L4-L5 intertransverse space: TCP scaffold (n=6), MSC/TCP (n=6), and MSC/Bac/TCP (n=6). After 12 weeks, the rabbits were euthanized for radiographic examination, manual palpation, and histologic study., Results: Bilateral fusion areas in each animal were evaluated independently. The radiographic fusion rates at 12 sites were 0 of 12 in the TCP scaffold group, 4 of 12 in the MSC/TCP group, and 10 of 12 in the MSC/Bac/TCP group. By manual palpation, there were zero solid fusions in the TCP scaffold group, two solid fusions in the MSC/TCP group, and five solid fusions in the MSC/Bac/TCP group. Fusion rates were significantly greater in the MSC/Bac/TCP group., Conclusions: The results indicate the potential of using baculovirus as a vector for gene/cell therapy approaches to improve bone healing and support the feasibility of using allogeneic MSCs for inducing bone formation and intertransverse process fusion., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Traditional approaches to deformity correction of degenerative lumbar scoliosis include anterior-posterior approaches and posterior-only approaches. Most patients are treated with posterior-only approaches because the high complication rate of anterior approach. Our purpose is to compare and assess outcomes of combined anterior lumbar interbody fusion and instrumented posterolateral fusion with posterior alone approach for degenerative lumbar scoliosis with spinal stenosis., Methods: Between November 2002 and November 2011, a total of 110 patients with degenerative spinal deformity and curves measuring over 30° were included. Of the 110 patients who underwent surgery, 56 underwent the combined anterior and posterior approach and 54 underwent posterior surgery at our institution. The following were the indications of anterior lumbar interbody fusion: (1) rigid or frank lumbar kyphosis, (2) anterior or lateral bridged traction osteophytes, (3) gross coronal and sagittal deformity or imbalance, and (4) severe disc space narrowing that is not identifiable when performing posterior or transforaminal lumbar interbody fusion. The clinical outcomes were evaluated using the Oswestry disability index and the visual analog scale. The status of fusion were assessed according to the radiographic findings., Results: All patients received clinical and radiographic follow-up for a minimum of 24 months, with an average follow-up of 53 months (range, 26-96 months). At the final follow-up, the mean ODI score improved from 28.8 to 6.4, and the mean back/leg VAS, from 8.2/5.5 to 2.1/0.9 in AP group and the mean ODI score improved from 29.1 to 6.2, and the mean back/leg VAS, from 9.0/6.5 to 2.3/0.5 in P group. The mean scoliotic angle changed from 41.3° preoperatively to 9.3°, and the lumbar lordotic angle, from 3.1° preoperatively to 35.7° in AP group and the mean scoliotic angle from 38.5 to 21.4 and the lumbar lordotic angle from 6 to 15.8 in P group. There were significant differences in sagittal (P = 0.009) and coronal (P = 0.02) plane correction between the two groups., Conclusions: Our results demonstrate that combined anterior lumbar interbody fusion and instrumented posterolateral fusion for adult degenerative lumbar scoliosis effectively improves sagittal and coronal plane alignment than posterior group and both group were effectively improves clinical scores.

Sulfatase 1 (SULF1) plays a key role in cell signaling involving in cell growth, differentiation, proliferation, and migration. Abnormal SULF1 expression has been implicated in the development of various cancers and diseases of the skeletal and nervous systems. The present study aims to examine the difference in SULF1 expression between degenerative and non-degenerative intervertebral discs (IVDs) to provide an enhanced understanding of disc degeneration. Degenerative and non-degenerative disc tissues were surgically harvested from patients and experimental rats. Disc degeneration-specific genes were identified by microarray analysis. The gene expression of SULF1 was measured by sulfatase assay, reverse transcription-polymerase chain reaction (RT-PCR), real-time RT-PCR, and western blotting. Also, the presence of SULF1 in human and rat discs was confirmed by immunohistochemistry. More specifically in human cells, an increase of SULF1 gene expression was observed in degenerative cells at both mRNA and protein levels, as well as in time- and dose-dependent manner in response to TNF-α treatment. Increased staining of SULF1 was detected in degenerative discs compared to non-degenerative discs for humans and rats. These findings show an upregulation of SULF1 in degenerative discs for the first time, and suggest that there is a link between SULF1 and disc degeneration., (© 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Background Context: Postoperative symptomatic epidural hematoma (SEH) is a serious complication of lumbar spine surgery. Despite its rarity, this uncommon complication may result in devastating neurological sequelae, including lower limb weakness., Purpose: A retrospective study was made to identify possible risk factors of postoperative spinal epidural hematoma by reviewing the clinical cases of this rare complication and analyzing the postoperative evaluations of patients., Methods: From 2002 to 2010, out of 15,562 who underwent lumbar decompression procedure with/without instrumentation, 25 patients required reoperation for epidural hematoma after the initial spinal surgery. For the control group, another 75 patients were randomly selected from the pool of patients who received lumbar decompression surgery during the same period of time. The medical records of preoperative, intraoperative and postoperative factors were collected to determine possible risk factors by comparing between the cases and controls, and the postoperative evaluations of muscle power, intractable pain, saddle anesthesia, time to detection and time to evacuation were analyzed to find if there is any significant relation within the case group. Mann-Whitney U test, two-sample t test, χ (2) test and Fisher's exact test were used for statistical analysis., Results: The incidence of postoperative symptomatic epidural hematoma is 0.16%. After the initial procedure, 20 (80%) patients developed progressive decrease in muscle power (MP ≤ 3), 14 (56%) patients had intractable pain (VAS ≥ 7), and 19 (76%) patients had saddle anesthesia. Preoperative diastolic blood pressure, intraoperative use of gelfoam for dura coverage and postoperative drain output were statistically significant risk factors (p < 0.01). Within the SEH case group, postoperative symptom of decreased muscle power had significant relation with blood loss, laminectomy level and fusion level (p = 0.016, 0.021, 0.010). If the symptom of decreased muscle power or perianal anesthesia was not improved after hematoma evacuation, there was a tendency for permanent leg weakness after 1-year follow-up (p = 0.001, 0.003)., Conclusions: The findings suggest that preoperative diastolic blood pressure, intraoperative use of gelfoam for dura coverage and postoperative drain output are risk factors for symptomatic epidural hematoma after lumbar decompression surgery. Major blood loss and multilevel surgical procedure could result in poor recovery of muscle power. After spine decompression surgery, early detection and evacuation of hematoma are the key to avoid neurologic deterioration and have better clinical outcomes.

Background: Percutaneous pedicle screw instrumentation is a minimally invasive surgical technique; however, the effects of using percutaneous pedicle screw fixation in treating patients with spinal infections have not yet been well demonstrated. The aim of this study, therefore, was to determine whether percutaneous posterior pedicle screw instrumentation is superior to the traditional open approach in treating pyogenic spondylodiscitis., Methods: We retrospectively reviewed data for 45 patients treated for pyogenic spondylodiscitis with anterior debridement and interbody fusion followed by a second-stage procedure involving either traditional open posterior pedicle screw fixation or percutaneous posterior pedicle screw fixation. Twenty patients underwent percutaneous fixation and 25 patients underwent open fixation. Demographic, operative, and perioperative data were collected and analyzed., Results: The average operative time for the percutaneous procedure was 102.5 minutes, while the average time for the open procedure was 129 minutes. The average blood loss for the percutaneous patients was 89 ml versus a 344.8 ml average for the patients in the open group. Patients who underwent the minimally invasive surgery had lower visual analogue scale scores and required significantly less analgesia afterwards. After two years of follow-up, neither recurrent infection nor intraoperative complications, such as wound infection or screw loosening, were found in the percutaneous group. Moreover, there was no significant difference in outcome between the two groups in terms of Oswestry Disability Index scores., Conclusions: Anterior debridement and interbody fusion with bone grafting followed by minimally invasive percutaneous posterior instrumentation is an alternative treatment for pyogenic spondylodiscitis which can result in less intraoperative blood loss, shorter operative time, and reduced postoperative pain with no adverse effect on infection control.

Mechanotransduction plays a critical role in intracellular functioning--it allows cells to translate external physical forces into internal biochemical activities, thereby affecting processes ranging from proliferation and apoptosis to gene expression and protein synthesis in a complex web of interactions and reactions. Accordingly, aberrant mechanotransduction can either lead to, or be a result of, a variety of diseases or degenerative states. In this review, we provide an overview of mechanotransduction in the context of intervertebral discs, with a focus on the latest methods of investigating mechanotransduction and the most recent findings regarding the means and effects of mechanotransduction in healthy and degenerative discs. We also provide some discussion of potential directions for future research and treatments., (© 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

Spinal fractures are commonly encountered in ankylosing spondylitis (AS) patients. This study compares the outcome of early surgical treatment with initial conservative treatment for thoracolumbar fractures in patients with AS. From 1996 to 2008, 28 patients with AS were treated either operatively or conservatively for thoracolumbar fractures; however, only 25 patients met the inclusion criteria with a minimum follow-up of 2 years. For surgically treated patients, posterior spinal instrumentation was performed using a transpedicle screw system. Nonsurgically treated patients wore a fracture brace. The demographic data, diagnosis, mechanism of injury, and neurological status were recorded, and fracture healing was assessed radiographically. The mean age was 54.2 ± 13.8 years (range 30-80 years). Six patients (Group A) received surgical intervention within 1 month. All of these fractures healed, and two of five patients showed neurologic improvement after surgery. Eight patients (Group B) had fractures that were missed. The delay in diagnosis resulted in pseudoarthrosis in all cases, and progressive neurologic deficits were identified in four cases. Eleven patients (Group C) received conservative treatment with bracing. Fracture union was achieved in three cases, and pseudoarthrosis occurred in eight cases. Operative treatment can achieve solid fusion and improve the neurological status, while conservative treatment may result in pseudoarthrosis and progressive neurologic deficit. The results suggest that AS patients with unstable spinal fractures should receive early surgical management to prevent further sequelae.

Parkinson's disease is known to result from the loss of dopaminergic neurons. Direct intracerebral injections of high doses of recombinant glial cell line-derived neurotrophic factor (GDNF) have been shown to protect adult nigral dopaminergic neurons. Because GDNF does not cross the blood-brain barrier, intracerebral gene transfer is an ideal option. Chitosan (CHI) is a naturally derived material that has been used for gene transfer. However, the low water solubility often leads to decreased transfection efficiency. Grafting of highly water-soluble polyethylene imines (PEI) and polyethylene glycol onto polymers can increase their solubility. The purpose of this study was to design a non-viral gene carrier with improved water solubility as well as enhanced transfection efficiency for treating Parkinsonism. Two molecular weights (Mw =600 and 1,800 g/mol) of PEI were grafted onto CHI (PEI600-g-CHI and PEI1800-g-CHI, respectively) by opening the epoxide ring of ethylene glycol diglycidyl ether (EX-810). This modification resulted in a non-viral gene carrier with less cytotoxicity. The transfection efficiency of PEI600-g-CHI/deoxyribonucleic acid (DNA) polyplexes was significantly higher than either PEI1800-g-CHI/DNA or CHI/DNA polyplexes. The maximal GDNF expression of PEI600-g-CHI/DNA was at the polymer:DNA weight ratio of 10:1, which was 1.7-fold higher than the maximal GDNF expression of PEI1800-g-CHI/DNA. The low toxicity and high transfection efficiency of PEI600-g-CHI make it ideal for application to GDNF gene therapy, which has potential for the treatment of Parkinson's disease.

Background: The biomechanical performance of the hooks and screws in spinal posterior instrumentation is not well-characterized. Screw-bone interface failure at the uppermost and lowermost vertebrae is not uncommon. Some have advocated for the use of supplement hooks to prevent screw loosening. However, studies describing methods for combined hook and screw systems that fully address the benefits of these systems are lacking. Thus, the choice of which implant to use in a given case is often based solely on a surgeon's experience instead of on the biomechanical features and advantages of each device., Methods: We conducted a biomechanical comparison of devices instrumented with different combinations of hooks and screws. Thirty-six fresh low thoracic porcine spines were assigned to three groups (12 per group) according to the configuration used for of fixation: (1) pedicle screw; (2) lamina hook and (3) combination of pedicle screw and lamina hook. Axial pullout tests backward on transverse plane in the direction normal to the rods were performed using a material testing machine and a specially designed grip with self-aligned function., Results: The pullout force for the pedicle screws group was significantly greater than for the hooks and the combination (p < 0.05). However, no significant difference was found between the hooks and the combination (p > 0.05)., Conclusions: Pedicle screws achieve the maximal pullout strength for spinal posterior instrumentation.

Background: An in vivo animal study and a prospective clinical study have indicated that bone marrow aspirate (BMA) augments spinal arthrodesis. However, there is no quantified data to explain why fusion rate can be augmented by BMA in lumbar posterolateral fusion., Methods: To analyze the proportion of mesenchymal stem cells (MSCs) and osteogenic factors in human BMA and peripheral blood (PB) of the same patient. Autologous BMA and PB from the patients were analyzed by flow cytometry (FACS) using cell markers for MSCs. The osteogenic potential of MSCs was determined by alkaline phosphatase (ALP) activity and calcium level quantification. Proteomics were used for the qualitative and quantitative mapping of the whole proteome from BMA and PB plasma. The mass-to-charge ratio was calculated by time-of-flight mass spectrometry (TOF-MS). The overexpression of protein was confirmed using Western blot analysis., Results: The proportion of MSCs (CD34-/CD29+/CD105+) was higher in the BMA than that in the PB. Colony-forming cell (CFC) assays suggested that fewer colonies were formed in PB cultures than in BMA culture. There was no significant difference in the osteogenic potential of the MSCs between the PB and BMA. Proteomic mass spectrometry assays suggested that the levels of catalase (osteoclast inhibitor) and glutathione peroxidase 3 (osteogenic biomarker) were higher in the BMA than those in the PB, and this was confirmed by Western blot analysis., Conclusions: The proportions of MSCs and osteogenic factors were higher in the BMA than in the PB. This may explain why fusion rate can be augmented by BMA in lumbar posterolateral fusion.

Background: Postoperative bacterial meningitis is a rare complication of spinal surgery and is considered to be a complication related to intraoperative incidental durotomy. A high index of suspicion for meningitis is essential in patients who have the clinical triad of fever, neck stiffness and consciousness disturbance during the postoperative period. A delay in diagnosis or treatment can lead to morbidity and mortality. Due to the low incidence of postoperative meningitis, very few studies have reported this complication. The purpose of this study was to report the clinical features, laboratory evaluations, treatment course and prognosis of 21 patients with post spinal surgery meningitis., Methods: We retrospectively reviewed 21 patients (13 male, 8 female) with the diagnosis of postoperative meningitis after lumbar spinal surgery between January 2001 and Aug 2011. The median age of the patients was 67 years old (range 27 to 82 years) at the time of surgery. We recorded the preoperative diagnosis, operative methods, amount of drainage, clinical manifestations, laboratory evaluations, cerebrospinal fluid study, and infectious organisms. All patients diagnosed with postoperative meningitis received at least two weeks of antibiotic treatment. Clinical outcomes were assessed after at least two years of follow-up., Results: From January 2001 to August 2011, 20,178 spinal operations were performed in our institution, and 21 patients (0.10%) were diagnosed with postoperative meningitis. Eighteen patients (85.7%) had fever, 19 (90.5%) had neck stiffness, and 16 (76.2%) had consciousness disturbance. All patients had at least two of the classic triad. In addition, 9 patients (42.9%) had headache, 3 (14.3%) had focal neurological deficits, and 2 (9.5%) had seizure attacks. There was no mortality in this series. Postoperative meningitis showed no adverse effect on the results of spinal surgery after follow-up for at least two years., Conclusions: Postoperative meningitis is a rare complication after spinal lumbar surgery. A high index of suspicion for meningitis should be maintained in patients with the clinical triad of fever, neck stiffness, and consciousness disturbance after spinal surgery. Intraoperative incidental durotomy is the most important predictor. An early diagnosis and appropriate antibiotic treatment can lead to a good outcome.

Thermosensitive micelles composed of a copolymer of methoxy polyethylene glycol (mPEG), polylactic acid (PLA), and 1,6-bis (p-carboxyphenoxy) hexane (CPH), namely methoxy polyethylene glycol-co-polylactic acid-co-aromatic anhydride (mPEG-PLCPHA), were fabricated for application as a promising hydrophilic drug carrier. The copolymer can self-assemble into micelles in PBS by hydrophobic interaction. The diameters of these micelles increased as the environmental temperature increased. An increase in viscosity with sol-to-gel transition occurred as temperature increased from room temperature to body temperature. During the in vitro degradation process, hydrogels demonstrated a more stable degradation rate. Both in vitro and in vivo cytotoxicity results showed that the materials had excellent biocompatibility due to less acidic products formation. In vitro cefazolin release profiles showed a stable release for 30 days. The hydrogel encapsulated cefazolin exhibited a good antibacterial effect. Based on these results, mPEG-PLCPHA can serve as an injectable depot gel for drug delivery., From the Clinical Editor: In this study, thermosensitive hydrogel encapsulated cefazolin was found to exhibit good antibacterial effects with sustained levels for up to 30 days, enabling the development of an injectable depot gel for long-term drug delivery., (© 2013.)

Background: Lumbar spine facet joints are arranged sagittally and mainly provide forward flexibility. Rotation of the lumbar vertebral body and coronal plane deformity may influence the function of lumbar forward flexibility. We hypothesize that the more advanced axial and coronal plane deformity could cause more limitation on forward flexibility in patients with idiopathic scoliosis., Methods: Between January 2011 and August 2011, 85 patients with adolescent idiopathic scoliosis were enrolled in this study. The proximal thoracic, major thoracic, thoracolumbar/lumbar (TL/L), and lumbar (L1/L5) curves were measured by Cobb's method. Lumbar apical rotation was graded using the Nash-Moe score. Lumbar forward flexibility was measured using the sit and reach (S and R) test. Statistical analysis was performed using one-way analysis of variance (ANOVA), Spearman's and Pearson's correlation coefficients., Results: The mean age was 16.1 ± 2.84 years. The mean proximal thoracic, major thoracic, TL/L, and L1/L5 curves were 17.61° ± 8.92, 25.56° ± 11.61, 26.09° ± 8.6, and 15.10° ± 7.85, respectively. The mean S and R measurement was 25.56 ± 12.33 cm. The magnitude of the TL/L and L1/L5 curves was statistically positively related to vertebral rotation (r(s) = 0.580 and 0.649, respectively). The correlation between the S and R test and both the TL/L and L1/L5 curves was negative (r(p) = -0.371 and -0.595, respectively). Besides, the S and R test also demonstrated a significant negative relationship with vertebral rotation (rs = -0.768)., Conclusion: In patients with idiopathic scoliosis, spinal deformity can diminish lumbar forward flexibility. Higher lumbar curvature and rotation lead to greater restriction of lumbar flexion.

Diabetes mellitus (DM) has been clinically proved as a risk factor of disc degeneration, and the accumulation of advanced glycation end products (AGEs) is known to be potentially involved in diabetes. The purpose of this study is to investigate the effect of AGEs in the degeneration process of diabetic nucleus pulposus (NP) in rats and humans. Diabetic NP cells from rat coccygeal discs were treated with different concentrations of AGEs (0, 50, and 100 µg/ml) for 3 days, and mRNA expressions of MMP-2 and RAGE were measured by real-time RT-PCR. In addition, conditioned medium from NP cells was used to analyze protein expression of MMP-2 activity and ERK by gelatin zymography and Western blot. These experiments were repeated using human intervertebral disc samples. The immunohistochemical expression of AGEs was significantly increased in diabetic discs. In response to AGEs, an increase of MMP-2, RAGE, and ERK at both mRNA and protein expression levels was observed in diabetic NP cells. The findings suggest that AGEs and DM are associated with disc degeneration in both species. Hyperglycemia in diabetes enhances the accumulation of AGEs in the NP and triggers disc degeneration., (© 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Background: Vertebral compression fractures (VCFs) constitute a major health care problem, not only because of their high incidence but also because of their direct and indirect negative impacts on both patients' health-related quality of life and costs to the health care system. Two minimally invasive surgical approaches were developed for the management of symptomatic VCFs: balloon kyphoplasty and vertebroplasty. The purpose of this study was to evaluate the effectiveness and safety of balloon kyphoplasty in the treatment of symptomatic VCFs., Methods: Between July 2011 and June 2012, one hundred and eighty-seven patients with two hundred and fifty-one vertebras received balloon kyphoplasty in our hospital. There were sixty-five male and one hundred and twenty-two female patients with an average age of 74.5 (range, 61 to 95 years). The pain symptoms and quality of life, were measured before operation and at one day, three months, six months and one year following kyphoplasty. Radiographic data including restoration of kyphotic angle, anterior vertebral height, and any leakage of cement were defined., Results: The mean visual analog pain scale decreased from a preoperative value of 7.7 to 2.2 at one day (p < .05) following operation and the Oswestry Disability Index improved from 56.8 to 18.3 (p < .05). The kyphotic angle improved from a mean of 14.4° before surgery to 6.7° at one day after surgery (p < .05). The mean anterior vertebral height increased significantly from 52% before surgery to 74.5% at one day after surgery (p < .05) and 70.2% at one year follow-up. Minor cement extravasations were observed in twenty-nine out of two hundred and fifty-one procedures, including six leakage via basivertebral vein, three leakage via segmental vein and twenty leakage through a cortical defect. None of the leakages were associated with any clinical consequences., Conclusions: Balloon kyphoplasty not only rapidly reduced pain and disability but also restored sagittal alignment in our patients at one-year follow-up. The treatment of osteoporotic vertebral compression fractures with balloon kyphoplasty is a safe, effective, and minimally invasive procedure that provides satisfactory clinical results.

Background: Patients with liver cirrhosis have high surgical risks due to malnutrition, impaired immunity, coagulopathy, and encephalopathy. However, there is no information in English literature about the results of liver cirrhotic patients who underwent instrumented lumbar surgery. The purpose of this study is to report the perioperative complications, clinical outcomes and determine the surgical risk factors in cirrhotic patients., Methods: We retrospectively reviewed 29 patients with liver cirrhosis who underwent instrumented lumbar surgery between 1997 and 2009. The hepatic functional reserves of the patients were recorded according to the Child-Turcotte-Pugh scoring system. Besides, fourteen other variables and perioperative complications were also collected. To determine the risks, we divided the patients into two groups according to whether or not perioperative complications developed., Results: Of the 29 patients, 22 (76%) belonged to Child class A and 7 (24%) belonged to Child class B. Twelve patients developed one or more complications. Patients with Child class B carried a significantly higher incidence of complications than those with Child class A (p = 0.011). In the Child class A group, patients with 6 points had a significantly higher incidence of complications than those with 5 points (p = 0.025). A low level of albumin was significantly associated with higher risk, and a similar trend was also noted for the presence of ascites although statistical difference was not reached., Conclusion: The study concludes that patients with liver cirrhosis who have undergone instrumented lumbar surgery carry a high risk of developing perioperative complications, especially in those with a Child-Turcotte-Pugh score of 6 or more.

Background: There is no information in the English literature on the outcome of liver cirrhotic patients who have undergone instrumented lumbar surgery., Purpose: To review the results of instrumented lumbar surgery in patients with liver cirrhosis and determine the surgical risk factors in this group of patients., Study Design: A retrospective study for comparison between two cohorts (liver cirrhosis vs. nonliver cirrhosis)., Patient Sample: Fifty-eight patients., Outcome Measures: Child-Turcotte-Pugh scale was used to assess the patients' hepatic functional reserve. The clinical outcomes were evaluated by the five-grade patient-centered general outcome assessment questionnaire. Any event that led to reoperation, requirement of intensive care, prolonging of the hospital stay (more than 14 days), or admission after discharge within 30 days of surgery was defined as a perioperative complication., Methods: Between 1997 and 2009, patients with liver cirrhosis who had undergone instrumented lumbar surgeries for degenerative lumbar disease were studied. All data were compared with those for gender-, age-, and diagnosis-matched nonliver cirrhosis patients., Results: Liver cirrhotic patients had significantly lower preoperative hemoglobin, white blood cell counts, platelets, and albumin levels and higher prothrombin time and bilirubin level. Instrumented lumbar surgery was associated with significantly more blood loss, a longer hospital stay, and more complications in patients with liver cirrhosis compared with control patients. The final satisfactory rate was higher in the control group but without statistical difference (85% vs. 65%, p=.240). In the cirrhotic group, 22 patients (76%) were Child Class A and 7 patients (24%) were Child Class B; 12 patients developed one or more complications. Patients with Child Class B had a significantly higher incidence of complications than those with Child Class A (p=.006). In patients with Child Class A, those with a score of 6 also had a significantly higher incidence of complications than those with a score of 5 (p<.001). Female gender (p=.035), a low level of albumin (p=.002), presence of ascites (p=.029), and increased blood loss (p=.044) were associated with a higher risk of complications., Conclusions: The rate of complications after instrumented lumbar surgery was significantly higher in patients with cirrhosis than in control patients, especially in those with 6 or more Child-Turcotte-Pugh points. The surgeon should counsel these patients on the possibility of developing early complications. Several factors were associated with surgical complications and should be addressed by the spine surgeons before or when they perform these elective instrumented lumbar surgeries., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Vertebral compression fracture is the most common complication of osteoporosis. It may result in persistent severe pain and limited mobility, and significantly impacts the quality of life. Vertebroplasty involves a percutaneous injection of bone cement into the collapsed vertebrae by fluorescent guide. The most commonly used bone cement in percutaneous vertebroplasty is based on the polymerization of methylmethacrylate monomers to polymethylmethacrylate (PMMA) polymers. However, information on the properties of bone cement is mostly published in the biomaterial sciences literature, a source with which the clinical community is generally unfamiliar. This review focuses on the chemistry of bone cement polymerization and the physical properties of PMMA. The effects of altering the portions and contents of monomer liquid and polymer powders on the setting time, polymerization temperature, and compressive strength of the cement are also discussed. This information will allow spine surgeons to manipulate bone cement characteristics for specific clinical applications and improve safety.

Background Context: Disc degeneration is a multifactorial disease that may cause clinical symptoms such as chronic back pain or radiculopathy in the extremities. Periostin, an extracellular matrix protein involved in the process of fibrosis, expressed in tissues subjected to mechanical stress such as intervertebral disc. However, the expression of periostin during disc degeneration has not yet been studied., Purpose: The aim of this study is to elucidate the difference in gene expression profiles between degenerative and nondegenerative intervertebral discs for a better understanding of disc degeneration., Study Design: Degenerative and nondegenerative nucleus pulposus cells were isolated from elderly patients with degenerative disc disease and younger patients with adolescent idiopathic scoliosis, respectively., Methods: Affymetrix GeneChip Human arrays were used to derive gene expression profiles for disc degeneration, and gene expressions of periostin and other degeneration-related markers were confirmed by reverse transcription-polymerase chain reaction (RT-PCR), real-time RT-PCR, and western blot analysis. Immunohistochemical analysis of periostin and Gomori trichrome stain was performed to show the relationship of periostin, fibrosis, and disc degeneration. The mechanical stress experiment was designed to demonstrate the relationship of periostin, stress, and disc degeneration., Results: Fourteen genes were identified to express at significantly different levels between degenerative and nondegenerative groups. An increase of periostin gene expression was observed in human degenerative nucleus pulposus cells for the messenger RNA and protein levels. Histological examination demonstrated an increased positive staining of periostin in degenerative discs from human tissues and rat needle-punctured tails and more fibrosis with architectural disorder and fragmentation in human degenerative disc as compared with nondegenerative discs. The expression of periostin was significantly induced by stress in human degenerative nucleus pulposus cells but not in nondegenerative cells., Conclusions: This study demonstrates for the first time an upregulation of periostin in addition to the expression levels of Type I collagen and matrix metalloproteinase-2 in human disc degeneration. It suggests that periostin may be a candidate gene that shows promise as a new prognostic marker and a therapeutic target that is worth further study to expand our knowledge of its role in disc degeneration., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Nucleus pulposus cells (NPCs) from degenerating discs produce catabolic and inflammatory factors, including interleukin (IL)-1 and nitric oxide (NO). Enhanced production of NO has been implicated in the apoptosis of degenerating disc cells. This study evaluates the effects of hyperbaric oxygen (HBO) on degenerated human NPCs. All hyperoxic cells were exposed to 100% O(2) at 2.5 atmospheres absolute (ATA). Phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) in NPCs was detected using the phosphor-kinase array kit. RNA was isolated for real-time polymerase chain reaction (PCR) analysis of aggrecan and type II collagen gene expression. The levels of IL- 1β and NO were quantified by enzyme-linked immunosorbent assay (ELISA). To identify the HBO-induced anti-apoptotic pathways, expression of Bcl-2 and Bax proteins as well as activation of cysteine-containing aspartate-specific proteases (caspases) 3, 8, and 9 was evaluated using Western blotting after HBO treatment. Our data showed that HBO treatment decreased the expression of IL-1β, suppressed phosphorylation of ERK1/2, JNK, and p38 MAPK, decreased synthesis of NO, and increased the gene expression of aggrecan and type II collagen in NPCs as compared with the atmospheric treatment. HBO up-regulated the ratio of Bcl-2 to Bax expression and reduced the activity of caspases 9 and 3 but not of caspase 8, indicating a selective effect over the mitochondrial apoptosis pathway in degenerated NPCs. These results support our hypothesis that HBO treatment suppresses MAPK signaling and mitochondrial apoptotic pathway in degenerated human intervertebral disc cells., (Copyright © 2012 Orthopaedic Research Society.)

Background: Polymethylmethacrylate (PMMA) is commonly used for clinical applications. However, the short handling time increases the probability of a surgeon missing the crucial period in which the cement maintains its ideal viscosity for a successful injection. The aim of this article was to illustrate the effects a reduction in temperature would have on the cement handling time during percutaneous vertebroplasty., Methods: The injectability of bone cement was assessed using a cement compressor. By twisting the compressor, the piston transmits its axial load to the plunger, which then pumps the bone cement out. The experiments were categorized based on the different types of hypothermic manipulation that were used. In group I (room temperature, sham group), the syringes were kept at 22°C after mixing the bone cement. In group 2 (precooling the bone cement and the container), the PMMA powder and liquid, as well as the beaker, spatula, and syringe, were stored in the refrigerator (4°C) overnight before mixing. In group 3 (ice bath cooling), the syringes were immediately submerged in ice water after mixing the bone cement at room temperature., Results: The average liquid time, paste time, and handling time were 5.1 ± 0.7, 3.4 ± 0.3, and 8.5 ± 0.8 min, respectively, for group 1; 9.4 ± 1.1, 5.8 ± 0.5, and 15.2 ± 1.2 min, respectively, for group 2; and 83.8 ± 5.2, 28.8 ± 6.9, and 112.5 ± 11.3 min, respectively, for group 3. The liquid and paste times could be increased through different cooling methods. In addition, the liquid time (i.e. waiting time) for ice bath cooling was longer than for that of the precooling method (p < 0.05)., Conclusions: Both precooling (i.e. lowering the initial temperature) and ice bath cooling (i.e. lowering the surrounding temperature) can effectively slow polymerization. Precooling is easy for clinical applications, while ice bath cooling might be more suitable for multiple-level vertebroplasty. Clinicians can take advantage of the improved injectability without any increased cost.

Background: Incorrect placement of pedicle screws may lead to neurovascular injury, so the position is important for the reduction of spinal fractures. CT-based image-guided surgery has been promoted as a means to theoretically improve the accuracy of pedicle screw placement. Patients who underwent CT-based navigation-assisted pedicle screw fixation for thoracic or lumbar fractures were reviewed to evaluate the accuracy of pedicle screw placement for spinal fracture cases., Methods: A computed tomographic (CT)-based image-guided system (BrainLAB) was used for pedicle screw insertion in 14 patients with thoracic or lumbar spine fractures. The accuracy of pedicle screw placement was analyzed by the preoperative and postoperative Cobb's angle and sagittal screw angle with a review of radiographic images, and the penetration of the pedicle cortex by postoperative CT scans., Results: Under the guidance of CT-based navigation 102 screws were inserted. Cobb's angle was corrected to an average of 15 degrees in the 14 patients. The sagittal screw angle was less than 10 degrees for 92 (90.2 %) screws, and the overall average was 5 degrees. The results of the postoperative CT review showed only 3 (2.9 %) screws penetrated the pedicle cortex laterally and no screw penetrated medially. No iagtrogenic neurological injury was found., Conclusion: The accuracy of pedicle screw placement is crucial for thoracolumbar spine fracture fixation. The placement of pedicle screws can be done accurately with the aid of a CT-based image-guided system. Furthermore, this opens the possibility for surgeons to reduce radiation exposure by eliminating the need for intraoperative fluoroscopy.

Background: Vertebral compression fractures are common in multiple myeloma. Percutaneous vertebroplasty is used to stabilize vertebral collapse and treat the pain. The major technical drawbacks of percutaneous vertebroplasty are the potential for neural comprise and pulmonary embolism of cement from leakage of polymethylmethacrylate into epidural space and perivertebral veins. We have retrospectively evaluated the safety and complication of percutaneous vertebroplasty in the vertebral compression fractures resulting from multiple myeloma., Methods: From August 2003 to July 2008, we describe 24 patients with multiple myeloma who were treated for vertebral compression fractures with percutaneous vertebroplasty to a total of 36 vertebrae. There were 4 male and 20 female patients with an average age of 67 (range 54–81 years). The pain symptoms were measured on a visual analog pain scale and quality of life as measured by the physical component summary scale of the Short Form- 36 before operation and at 24 h, at 3 months and at 1 year following vertebroplasty. Radiography was reviewed for evidence of cement leakage and pulmonary complication., Results: The mean visual analog pain scale decreased from a preoperative value of 9.0–3.8 at 24 h following operation and SF-36 score improved from 22.1 to 41.8. Of the twenty-four patients, four had cement leakage (2 leak through inferior endplate into disc, 2 leak into perivertebral vessels). There were no intra-postoperative neurologic or pulmonary complications. Eight patients died 2–18 months post-operatively due to multiple myeloma-related organ failure., Conclusions: In this study, vertebroplasty significantly improved pain scores and function and, thereby, the quality of life. There were no major procedure-related complications in this study. Direct cytotoxic effect, polymerization and biomechanical microfractures stabilizer of polymethylmethacrylate play multiple roles in pain relief. In multiple myeloma, when pathological spinal compression fractures cause intractable pain and are unresponsive to conservative treatment, vertebroplasty remains the best option for pain relief and is effective in increasing quality of life.

Vertebral compression fracture is the most common complication of osteoporosis. It may result in persistent severe pain and limited mobility, and significantly impact the quality of life. Conservative therapy using external bracing, bed rest and analgesics is necessary for pain control in these patients. However, some patients may experience protracted or ongoing pain even with these measures. Surgical treatment is indicated when conservative treatment fails, or in patients with spinal instability or neurologic deficit. Elderly patients often have comorbilities, and because of osteoporosis, high risk of postoperative complications such as implant loosening, and further adjacent fractures. Vertebroplasty involves a percutaneous injection of bone cement into the collapsed vertebrae under fluroscopic imaging guidance. It was first reported in 1987 for the management of a painful, aggressive hemangioma of a vertebral body. Since then, vertebroplasty has been widely accepted for the treatment of vertebral osteoporotic compression fractures without neurological damage. This article summarizes the advances in vertebroplasty, and discusses the indications, technique, alternative methods, results and complications. The contents include a review of the supporting evidence to provide a comparison of the safety and efficacy of vertebroplasty and kyphoplasty.