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1.
Small ; : e2000655, 2020 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-32363753

RESUMO

Nitric oxide (NO) is a potent tumor-cell radiosensitizer but it can be readily scavenged by hemoglobin (Hb) in vivo. A biomimetic incubator that can generate and deliver NO in a scavenger (Hb)-free environment to enhance its radiosensitizing effect to maximize its efficacy in radiotherapy is proposed. This NO incubator comprises a poly(lactic-co-glycolic acid) (PLGA) hollow microsphere (HM) that contains an NO donor (NONOate) and a surfactant molecule (sodium caprate, SC) in its aqueous core. In acidic tumorous environments, the PLGA shell of the HM allows the penetration of protons from the outside, activating the hydrolytic cleavage of NONOate, spontaneously generating NO bubbles, which are immediately trapped/stabilized by SC. The SC-stabilized NO bubbles in the HM are then squeezed through the spaces of its PLGA matrices by the elevated internal pressure. Upon leaving the HM, the entrapped NO molecules may passively diffuse through their SC-stabilized/protected layer gradually to the tumor site, having a long-lasting radiosensitizing effect and inhibiting tumor growth. The entire process of NO generation and delivery is conducted in a scavenger (Hb)-free environment, mimicking the development of young ovoviviparous fish inside their mothers' bodies in the absence of predators before birth.

2.
PLoS One ; 15(2): e0229328, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084219

RESUMO

Pedicle screw loosening resulting from insufficient bone-screw interfacial holding power is not uncommon. The screw shape and thread profile are considered important factors of the screw fixation strength. This work investigated the difference in pullout strength between conical and cylindrical screws with three different thread designs. The effects of the thread profiles on the screw fixation strength of cannulated screws with or without cement augmentation in osteoporotic bone were also evaluated. Commercially available artificial standard L4 vertebrae and low-density polyurethane foam blocks were used as substitutes for healthy vertebrae and osteoporotic bones, respectively. The screw pullout strengths of nine screw systems were investigated (six in each). These systems included the combination of three different screw shapes (solid/cylindrical, solid/conical and cannulated/cylindrical) with three different thread profiles (fine-thread, coarse-thread and dual-core/dual-thread). Solid screws were designed for the cementless screw fixation of vertebrae using the standard samples, whereas cannulated screws were designed for the cemented screw fixation of osteoporotic bone using low-density test blocks. Following specimen preparation, a screw pullout test was conducted using a material test machine, and the maximal screw pullout strength was compared among the groups. This study demonstrated that, in healthy vertebrae, both the conical and dual-core/dual-thread designs can improve pullout strength. A combination of the conical and dual-core/dual-thread designs may achieve optimal postoperative screw stability. However, in osteoporotic bone, the thread profile have little impact on the screw fixation strength when pedicle screws are fixed with cement augmentation. Cement augmentation is the most important factor contributing to screw pullout fixation strength as compared to screw designs.


Assuntos
Cimentos para Ossos/química , Osso e Ossos/fisiologia , Vértebras Lombares/cirurgia , Osteoporose/cirurgia , Parafusos Pediculares , Fusão Vertebral/instrumentação , Fenômenos Biomecânicos , Osso e Ossos/cirurgia , Humanos , Teste de Materiais , Fusão Vertebral/métodos
3.
Mol Ther ; 28(2): 441-451, 2020 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-31882321

RESUMO

CRISPR activation (CRISPRa) is a burgeoning technology for programmable gene activation, but its potential for tissue regeneration has yet to be fully explored. Bone marrow-derived mesenchymal stem cells (BMSCs) can differentiate into osteogenic or adipogenic pathways, which are governed by the Wnt (Wingless-related integration site) signaling cascade. To promote BMSC differentiation toward osteogenesis and improve calvarial bone healing by BMSCs, we harnessed a highly efficient hybrid baculovirus vector for gene delivery and exploited a synergistic activation mediator (SAM)-based CRISPRa system to activate Wnt10b (that triggers the canonical Wnt pathway) and forkhead c2 (Foxc2) (that elicits the noncanonical Wnt pathway) in BMSCs. We constructed a Bac-CRISPRa vector to deliver the SAM-based CRISPRa system into rat BMSCs. We showed that Bac-CRISPRa enabled CRISPRa delivery and potently activated endogenous Wnt10b and Foxc2 expression in BMSCs for >14 days. Activation of Wnt10b or Foxc2 alone was sufficient to promote osteogenesis and repress adipogenesis in vitro. Furthermore, the robust and prolonged coactivation of both Wnt10b and Foxc2 additively enhanced osteogenic differentiation while inhibiting adipogenic differentiation of BMSCs. The CRISPRa-engineered BMSCs with activated Wnt10b and Foxc2 remarkably improved the calvarial bone healing after implantation into the critical-sized calvarial defects in rats. These data implicate the potentials of CRISPRa technology for bone tissue regeneration.

4.
Mater Sci Eng C Mater Biol Appl ; 106: 110175, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31753362

RESUMO

Resorbable bioceramics offer advantages in healing bone defects due to their degradation capability. Degradation rates differ significantly from one bioceramic to another; nevertheless, the degradation rate should match the growth rate of new bone. In the present study, a head-to-head comparison of the degradation rate of calcium sulfate and tricalcium phosphate is conducted. First, the degradation behaviors of calcium sulfate and tricalcium phosphate are evaluated separately. The comparison indicates that the degradation rate of calcium sulfate is one order of magnitude faster than that of tricalcium phosphate. Along with a fast degradation rate, the formation of calcium phosphate on the surface of calcium sulfate pellets is also faster. A core-shell roll composed of a calcium sulfate core and a tricalcium phosphate shell is also prepared. After soaking the core-shell roll in phosphate buffered saline solution for 24 h, calcium phosphate precipitates form only on the surface of core, the part containing calcium sulfate anhydrite.


Assuntos
Materiais Biocompatíveis/química , Fosfatos de Cálcio/química , Cerâmica/química , Sulfato de Cálcio/química
5.
J Orthop Surg Res ; 14(1): 406, 2019 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-31783861

RESUMO

BACKGROUND: The risk factors, incidence, and clinical management of pulmonary cement embolism and neurological deficit during percutaneous vertebroplasty (PVP) were evaluated. METHODS: Three thousand one hundred and seventy-five patients with symptomatic osteoporotic vertebral compression fractures (OVCFs) treated with PVP were retrospectively reviewed in a single institution. Clinical parameters such as age, gender, number of fractures, and time from fracture to vertebroplasty were recorded at the time of surgery. Image and surgical parameters including the amount of cement, the vertebral level, uni- or bipedicle surgical approach, and leakage pattern were recorded. RESULTS: Type-C leakage, including paraspinal (25%), intradiscal (26%), and posterior (0.7%) leakage, was more common than type-B (11.4%) and type-S leaks (4.9%). Cement leakage into the spinal canal (type-C posterior) occurred in 26 patients (0.7%), and four patients needed surgical decompression. Three in nine patients with leakage into thoracic spine needed decompressive surgery, but only one of 17 patients into lumbar spine needed surgery (p < 0.01). Age, gender, number of fractures, and time from fracture to vertebroplasty were not risk factors of pulmonary cement embolism or neurological deficit. The risk factor of pulmonary cement embolism was higher volume of PMMA injected (p < 0.001) and risk factor of neurological deficit was type-C posterior cement leakage into thoracic spine. The incidence of pulmonary cement embolism was significantly high in the volume of PMMA injected (PMMA injection < 3.5 cc: 0%; 3.5-7.0 cc: 0.11%; > 7.0 cc: 0.9%; p < 0.01) which needed postoperative oxygen support. CONCLUSIONS: Cement leakage is relatively common but mostly of no clinical significance. Percutaneous vertebroplasty in thoracic spine and high amount of PMMA injected should be treated with caution in clinical practice.

6.
Biomed Mater ; 15(1): 015005, 2019 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-31634880

RESUMO

Using three-dimensional (3D) bone engineering to fabricate bone segments is a better choice for repairing bone defects than using autologous bone. However, biomaterials for bone engineering are burdened with some clinical safety concerns. In this study, we layered commonly found clinical materials, hemostatic gelatin sponges, in a novel manner to create a 3D scaffold for bone engineering purposes. We further examined the comparable benefits of our design with both closed- and open-bottom holders. Cells in stacked layer disc systems were examined after a week of growth and differentiation. Osteoblasts in the outer layers of both closed- and open-bottom holder systems displayed gradually increased alkaline phosphatase (ALP) activity but decreased osteopontin (OPN) expression. Further, cell proliferation assays and LIVE/DEAD staining revealed decreased viable cell counts in the top layer with increased incubation time. However, while layered disc systems with closed-bottom holders underwent differentiation, they kept more differentiated cells alive within the gelatin sponge disc scaffold after 28 d of culturing. Whether cells were inoculated into the top, middle, or bottom portions of the layered disc stack, osteoblasts showed a preference for migrating to the top layer, in keeping with the oxygen and nutrients gradients. Regarding practical application, this study offers valuable information to promote the use of hemostatic gelatin sponges for bone engineering.

7.
BMC Musculoskelet Disord ; 20(1): 497, 2019 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-31656190

RESUMO

BACKGROUND: The optimal anchor density in adolescent idiopathic scoliosis (AIS) surgery to achieve good curve correction remains unclear. The purpose of the study is to analyze the correlations between three-dimensional curve correction and anchor density in the pedicle screw-based posterior fusion of AIS. METHODS: One hundred and twenty-seven AIS patients receiving primary posterior fusion with pedicle screw instrumentation were retrospectively reviewed. Anchor density (AD) was defined as the screws number per fused spinal segment. The correlations between three-dimensional curve correction radiographic parameters and anchor density were analyzed with subgroup analysis based on different curve types, curve magnitudes, and curve flexibilities. The differences of curve correction parameters between the low-density (AD ≤1.4), middle-density (1.4 < AD ≤1.7) and high-density (AD > 1.7) groups were also calculated. Independent t-test, analysis of variance (ANOVA), and Pearson's correlation coefficient were used for statistical analysis. RESULTS: There were no correlations between the anchor density and the coronal curve correction or apical vertebral rotation (AVR) correction. In the sagittal plane, mild positive correlations existed between anchor density and thoracic kyphosis correction in all patients (r = 0.27, p = 0.002). Subgroup analysis revealed similar mild positive correlations in Lenke 1 (r = 0.31, p = 0.02), Lenke 1-3 (r = 0.27, p = 0.01), small curves (40°-60°, r = 0.38, p <  0.001), and flexible curves (flexibility > 40%, r = 0.34, p = 0.01). There were no differences between low-density (mean 1.31), middle-density (mean 1.55), and high-density (mean 1.83) in terms of coronal or axial curve correction parameters. Low-density group has longer fused level (mean difference 2.14, p = 0.001) and smaller thoracic kyphosis correction (mean difference 9.25°, p = 0.004) than high-density group. CONCLUSION: In our study, the anchor density was not related to coronal or axial curve corrections. Mild positive correlations with anchor density were found in thoracic kyphosis correction, especially in patients with smaller and flexible curves. Low anchor density with longer fusion level achieves similar curve corrections with middle or high anchor density in adolescent idiopathic scoliosis surgery.

8.
Biomed J ; 42(4): 285-292, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31627871

RESUMO

BACKGROUND: Percutaneous vertebroplasty has become the treatment of choice for compression fractures. Although the incidence is low, infection after vertebroplasty is a serious complication. The pathogens most often responsible for infection are bacteria. Meanwhile, mycobacterium tuberculosis-induced infection is extremely rare. In this study, we reported our treatment experience with 9 cases of tuberculous spondylitis after vertebroplasty. METHODS: Between January 2001 and December 2015, 5749 patients underwent vertebroplasty or kyphoplasty in our department. Nine cases developed tuberculous spondylitis after vertebroplasty (0.16%). Data on clinical history, laboratory examinations, image, treatment and outcomes were examined. RESULTS: One male and 8 female patients with a mean age of 75.1 years developed tuberculous spondylitis after vertebroplasty. 5 patients had a history of pulmonary tuberculosis (TB). Revision surgeries were performed from 5 days to 1124 days after vertebroplasty. Seven patients underwent anterior debridement and fusion with or without posterior instrumentation, and 2 cases received posterior decompression and instrumentation only. After operation, the diagnosis of tuberculous spondylitis was confirmed by TB polymerase chain reaction (TB-PCR) or mycobacteria culture. Mean follow-up period after revision surgery was 36.8 months. At the end of follow-up, 1 patient with paraplegia had passed away, 2 needed a wheel chair, 4 required a walker and 2 were able to walk unassisted. CONCLUSIONS: Vertebroplasty is a minimally invasive procedure but still retains some possibility of complications, including TB infection. Patients with a history of pulmonary TB or any elevation of infection parameters should be reviewed carefully to avoid infective complications.

9.
Biotechnol Adv ; 37(8): 107447, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31513841

RESUMO

CRISPR/Cas9 system exploits the concerted action of Cas9 nuclease and programmable single guide RNA (sgRNA), and has been widely used for genome editing. The Cas9 nuclease activity can be abolished by mutation to yield the catalytically deactivated Cas9 (dCas9). Coupling with the customizable sgRNA for targeting, dCas9 can be fused with transcription repressors to inhibit specific gene expression (CRISPR interference, CRISPRi) or fused with transcription activators to activate the expression of gene of interest (CRISPR activation, CRISPRa). Here we introduce the principles and recent advances of these CRISPR technologies, their delivery vectors and review their applications in stem cell engineering and regenerative medicine. In particular, we focus on in vitro stem cell fate manipulation and in vivo applications such as prevention of retinal and muscular degeneration, neural regeneration, bone regeneration, cartilage tissue engineering, as well as treatment of diseases in blood, skin and liver. Finally, the challenges to translate CRISPR to regenerative medicine and future perspectives are discussed and proposed.


Assuntos
Sistemas CRISPR-Cas , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Edição de Genes , Medicina Regenerativa , Células-Tronco
10.
Clin Biomech (Bristol, Avon) ; 70: 23-30, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31382200

RESUMO

BACKGROUND: Pedicle screw based spinal fixation systems have been widely used for treating a variety of spinal diseases. The retentive force is an important factor that determines structural stability. The screw tulip design and the magnitude of nut tightening torque influence the retentive force. This study investigated the influences of varied tilt angles between the shaft-rod interface and varied nut tightening torques on the retentive force of the monoaxial, polyaxial, and uniplanar screws. METHODS: Three types of tulip constructs were biomechanically tested. Two parameters that affect the retentive force include the tilt angle and the nut tightening torque. The retentive force was investigated by an axial gripping capacity test and axial torque gripping capacity test. FINDING: Among all combinations of screw designs and tilt angles, the 12 Nm nut tightening torque offered a greater retentive force than the 8 Nm, except for monoaxial screws with a 0 degree tilt angle. For monoaxial screws, the retentive force was negatively correlated with increasing tilt angles. For polyaxial and uniplanar screws, the retentive forces remained constant with increasing tilt angles. INTERPRETATION: In monoaxial screws, when the axis of the shaft isn't perpendicular to the axis of the rod, a gap is formed between the tulip-rod interface. This results in a decreased retentive force. In polyaxial and uniplanar screws, the contact surfaces were the same in different tilt angles, therefore, the retentive force remained constant, which was attributed to the adjustable tulips always being perpendicular to the axis of the rods.

11.
PLoS One ; 14(7): e0215499, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31318872

RESUMO

BACKGROUND: Cells, scaffolds, and factors are the triad of regenerative engineering; however, it is difficult to distinguish whether cells in the regenerative construct are from the seeded cells or host cells via the host blood supply. We performed a novel in vivo study to transplant enhanced green fluorescent pig mesenchymal stem cells (EGFP-pMSCs) into calvarial defect of DsRed pigs. The cell distribution and proportion were distinguished by the different fluorescent colors through the whole regenerative period. METHOD/RESULTS: Eight adult domestic Ds-Red pigs were treated with five modalities: empty defects without scaffold (group 1); defects filled only with scaffold (group 2); defects filled with osteoinduction medium-loaded scaffold (group 3); defects filled with 5 x 103 cells/scaffold (group 4); and defects filled with 5 x 104 cells/scaffold (group 5). The in vitro cell distribution, morphology, osteogenic differentiation, and fluorescence images of groups 4 and 5 were analyzed. Two animals were sacrificed at 1, 2, 3, and 4 weeks after transplantation. The in vivo fluorescence imaging and quantification data showed that EGFP-pMSCs were represented in the scaffolds in groups 4 and 5 throughout the whole regenerative period. A higher seeded cell density resulted in more sustained seeded cells in bone regeneration compared to a lower seeded cell density. Host cells were recruited by seeded cells if enough space was available in the scaffold. Host cells in groups 1 to 3 did not change from the 1st week to 4th week, which indicates that the scaffold without seeded cells cannot recruit host cells even when enough space is available for cell ingrowth. The histological and immunohistochemical data showed that more cells were involved in osteogenesis in scaffolds with seeded cells. CONCLUSION: Our in vivo results showed that more seeded cells recruit more host cells and that both cell types participate in osteogenesis. These results suggest that scaffolds without seeded cells may not be effective in bone transplantation.


Assuntos
Regeneração Óssea , Transplante de Células-Tronco Mesenquimais , Crânio/lesões , Animais , Células Cultivadas , Proteínas de Fluorescência Verde/análise , Células-Tronco Mesenquimais/citologia , Osteogênese , Crânio/ultraestrutura , Suínos , Tecidos Suporte/química , Transplante Homólogo
12.
World Neurosurg ; 130: e640-e647, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31276852

RESUMO

BACKGROUND: A considerable propotion of patients with cancer got thoracolumbar vertebral metastatic epidural spinal cord compression, which affected their quality of life. Traditional surgical management involves early decompression with concomitant spine stabilization with long instrumentation. However, complications are caused by massive blood loss and long operation time. This study aimed to compare the safety and efficacy of short posterior instrumentation with kyphoplasty and the traditional method for thoracolumbar metastatic epidural spinal cord compression. METHODS: Between January 2004 and December 2015, a retrospective study was conducted on 120 patients with metastatic epidural spinal cord compression from T6 to L5 and divided into 2 groups: short posterior instrumentation with the balloon kyphoplasty group (group I, n = 50) and the long posterior instrumentation group (group II, n = 70). The clinical and radiographic parameters of patients in the 2 groups were compared with a nonrandomized cohort method. Patients were followed up from 3 to 40 months after surgery according to survival time. RESULTS: In group I, the surgery had a mean blood loss of 650 mL and a survival time of 19.1 months. In group II, the surgery had a mean blood loss of 2100 mL and a survival time of 14.14 months. A significant difference in blood loss amount (P = 0.002) was observed. Complications, including deep wound infection, durotomy, and uncontrolled bleeding, were observed in both groups. No postoperative cement-induced neurologic deterioration, implant failure occurred. CONCLUSIONS: Kyphoplasty with short posterior instrumentation is a novel technique that can be performed safely and effectively for the treatment of thoracolumbar metastatic epidural spinal cord compression. Rigid stability, reduced blood loss, and short fixation decrease surgical morbidity of spinal metastasis.


Assuntos
Descompressão Cirúrgica/métodos , Cifoplastia/métodos , Vértebras Lombares/cirurgia , Compressão da Medula Espinal/cirurgia , Neoplasias da Coluna Vertebral/cirurgia , Vértebras Torácicas/cirurgia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Compressão da Medula Espinal/etiologia , Compressão da Medula Espinal/mortalidade , Neoplasias da Coluna Vertebral/complicações , Neoplasias da Coluna Vertebral/mortalidade , Taxa de Sobrevida , Resultado do Tratamento
13.
Spine (Phila Pa 1976) ; 44(21): E1231-E1240, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31181015

RESUMO

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 ±â€Š1.3 N, 10.5 ±â€Š0.4 N, and 48.4 ±â€Š14.4 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.


Assuntos
Escoliose/cirurgia , Fusão Vertebral/instrumentação , Coluna Vertebral/cirurgia , Animais , Fenômenos Biomecânicos , Feminino , Humanos , Vértebras Lombares/cirurgia , Procedimentos Neurocirúrgicos , Procedimentos Ortopédicos , Parafusos Pediculares , Coelhos , Amplitude de Movimento Articular , Suínos
14.
R Soc Open Sci ; 6(5): 182060, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31218032

RESUMO

Poly(methyl methacrylate) (PMMA) is the most frequently used bone void filler in orthopedic surgery. However, the interface between the PMMA-based cement and adjacent bone tissue is typically weak as PMMA bone cement is inherently bioinert and not ideal for bone ingrowth. The present study aims to improve the affinity between the polymer and ceramic interphases. By surface modifying nano-sized hydroxyapatite (nHAP) with ethylene glycol and poly(ɛ-caprolactone) (PCL) sequentially via a two-step ring opening reaction, affinity was improved between the polymer and ceramic interphases of PCL-grafted ethylene glycol-HAP (gHAP) in PMMA. Due to better affinity, the compressive strength of gHAP/PMMA was significantly enhanced compared with nHAP/PMMA. Furthermore, PMMA with 20 wt.% gHAP promoted pre-osteoblast cell proliferation in vitro and showed the best osteogenic activity between the composites tested in vivo. Taken together, gHAP/PMMA not only improves the interfacial adhesion between the nanoparticles and cement, but also increases the biological activity and affinity between the osteoblast cells and PMMA composite cement. These results show that gHAP and its use in polymer/bioceramic composite has great potential to improve the functionality of PMMA cement.

15.
PLoS One ; 14(6): e0219189, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31251780

RESUMO

Pedicles are often broken when screws are inserted into hard pedicles with small diameters or when the diameter of the screw itself is inadequate. However, there is a lack of biomechanical literature that addresses screw loosening as a result of broken pedicles or the resulting salvage of those screws. We performed a novel in vitro study to compare the pullout strength of screws between intact pedicles and two different types of broken pedicles; strategies to prevent screw loosening were also compared. Thirty L4 Sawbones were designed to represent intact pedicles, semi-pedicles, and nonpedicles and were prepared for screw insertion. Three sizes of polyaxial screws (diameter × length dimensions of 6.0 mm × 45 mm, 6.0 mm × 50 mm and 6.5 mm × 45 mm) were independently and randomly distributed into the intact-pedicle group (IP group, n = 30), the semi-pedicle group (SP group, n = 15), or the nonpedicle group (NP group, n = 15). The experiments were conducted across a minimum of five trials for each of the chosen screw sizes. We then analyzed the results of the imaging, pullout testing, and embedded bone volume. Any fractures or defects of the vertebrae caused by screw insertion were excluded from the study. The appropriate screw trajectory and insertional depth were confirmed using axial and sagittal X-ray imaging prior to screw pullout testing. A pullout strength of only 41% to 45% for the SP group and 29% to 39% for the NP group was retained following a broken pedicle. The use of longer or larger-diameter screws appears to be an effective salvaging procedure for the NP group (p < 0.05). The embedded bone volume percentage analysis indicated that, compared to the IP group, 68% to 76% of effective bone embedded into the screw threads in the SP group, and 58% to 65% in the NP group. There was no direct correlation between the pullout strength and the embedded bone volume; however, less effective embedded bone volume was associated with lower pullout strength. This study describes the evolution of the well-established screw pullout test being applied to the broken pedicle Sawbone testing model. The pedicle plays an important role in determining the pullout strength of a screw. However, a salvage procedure that utilizes a longer or larger-diameter screw might be a reliable clinical approach to address broken pedicles.


Assuntos
Teste de Materiais/métodos , Parafusos Pediculares/efeitos adversos , Fenômenos Biomecânicos , Osso e Ossos/diagnóstico por imagem , Falha de Equipamento , Humanos , Técnicas In Vitro
16.
World Neurosurg ; 128: e744-e751, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31077901

RESUMO

BACKGROUND: Minimally invasive transforaminal lumbar interbody debridement and fusion (MiTLIDF) with percutaneous pedicle screw instrumentation (PSI) is a less invasive treatment for lumbar spondylodiscitis. METHODS: Patients with single-level lumbar spondylodiscitis were surgically treated by interbody debridement and fusion through an anterior or transforaminal approach combined with open or percutaneous PSI (group A: anterior debridement and interbody fusion with open posterior PSI; group B: transforaminal lumbar interbody debridement and fusion [TLIDF] with open posterior PSI; group C: anterior debridement and interbody fusion with percutaneous PSI; group D: MiTLIDF with percutaneous PSI). Perioperative data, fusion status, infection-free survival, and clinical outcome measurements were compared among the 4 surgical groups. RESULTS: A total of 82 patients were included in this study. TLIDF was associated with shorter operative time when compared with the anterior approach (group A: 302.8 ± 59.9 minutes; group B: 209.2 ± 31.0 minutes; group C: 260.6 ± 62.5 minutes; group D: 207.1 ± 33.6 minutes; P < 0.001). Percutaneous PSI resulted in less intraoperative blood loss (group A: 907.5 ± 253.7 mL; group B: 859.4 ± 201.2 mL; group C: 532.9 ± 193.7 mL; group D: 399.1 ± 84.3 mL) and reduced immediate postoperative pain (group A: 5.5 ± 0.9; group B: 4.9 ± 0.9; group C: 3.9 ± 0.7; group D: 3.2 ± 0.7) than open PSI (P < 0.001). There were no significant differences in terms of overall infection-free survival (P = 0.936). CONCLUSIONS: This study demonstrated MiTLIDF with percutaneous PSI is a safe and effective treatment for lumbar spondylodiscitis while incurring no adverse effects in terms of fusion rate, functional recovery, and infection eradication.


Assuntos
Discite/cirurgia , Vértebras Lombares/cirurgia , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Parafusos Pediculares , Fusão Vertebral/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Perda Sanguínea Cirúrgica , Desbridamento , Feminino , Forame Magno/cirurgia , Humanos , /tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento
17.
Prog Biomater ; 8(2): 115-125, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31127540

RESUMO

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.

18.
BMC Musculoskelet Disord ; 20(1): 260, 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31142310

RESUMO

BACKGROUND: The risk of posterior cage migration (PCM) exists when a fusion cage is used for transforaminal lumbar interbody fusion (TLIF). This complication is influenced by contact pressure between the endplate and the cage. Previous reports demonstrated that anteriorly located cages bore more load and had greater strain than posteriorly located cages. However, there have been no detailed reports on the correlation between cage positioning and PCM. METHODS: From March 2014 to October 2015, we reviewed 953 patients receiving open transforaminal lumbar interbody fusion (TLIF) and bilateral pedicle screw instrumentation. One hundred patients without PCM were randomly sampled as the control group. Postoperative sagittal and coronal cage positions in the disc space were evaluated with the 'depth ratio' and the 'coronal ratio'. The demographic data of patients with and without PCM were compared to detect patient-related factors. Radiographic and cage related parameters, including cage position, preoperative disc height, preoperative spine stability, cage geometry, cage size, and height variance (= cage height - preoperative disc height) were compared between the PCM group and the control group. Univariate analyses and a multivariate logistic model were used to identify risk factors of PCM. RESULTS: Posterior cage migration occurred in 24 (2.52%) of 953 patients. The univariate and multivariate analyses revealed that those with a decreased depth ratio (OR, 9.78E-4; 95% CI, 9.69E-4 - 9.87E-4; p < 0.001) and height variance (OR, 0.757, 95% CI, 0.575-0997, p = 0.048) had a significantly higher risk of developing PCM. CONCLUSIONS: Our results verified that posteriorly located cages and undersized cages are more prone to developing PCM, which may aid surgeons in making optimal decisions during TLIF procedures.


Assuntos
Migração de Corpo Estranho/epidemiologia , Fixadores Internos/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Doenças da Coluna Vertebral/cirurgia , Fusão Vertebral/efeitos adversos , Idoso , Estudos de Casos e Controles , Tomada de Decisão Clínica , Feminino , Seguimentos , Migração de Corpo Estranho/diagnóstico por imagem , Migração de Corpo Estranho/etiologia , Humanos , Disco Intervertebral/anatomia & histologia , Disco Intervertebral/diagnóstico por imagem , Disco Intervertebral/patologia , Vértebras Lombares/anatomia & histologia , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/patologia , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/etiologia , Prevalência , Estudos Retrospectivos , Fatores de Risco , Doenças da Coluna Vertebral/diagnóstico por imagem , Doenças da Coluna Vertebral/patologia , Fusão Vertebral/instrumentação , Fusão Vertebral/métodos
19.
PLoS One ; 14(4): e0212161, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31009471

RESUMO

The purpose of this study was to determine whether functional walking performance measured with Timed Up-and-Go (TUG) and center of pressure (CoP) progression pattern is different across adolescents with various curve severity of idiopathic scoliosis (IS). The CoP coordinates during a stance phase for self-paced level walking between adolescent with three different severities of IS (mild IS, moderate IS, and severe IS) and age-matched normal subjects were measured with foot pressure measurement. The average data of three trials were compared among groups with repeated measure analysis of variance. Results showed that the TUG was different between normal and AIS subjects, indicating use of TUG as a marker of functional walking performance in AIS is plausible but studies with larger sample size is needed before using TUG to identify AIS with different scoliosis severity. The results also showed that the CoP displacement, velocity and acceleration during a stance phase was different across groups, and with the most prominent deviations found in the moderate IS group. The medial-lateral shifting of the CoP trajectory at mid-foot regions in all IS groups deviated the most. A tendency of asymmetry in CoP progression pattern between feet in IS groups was also found. The deviation of the spine alignment in frontal plane could change the CoP progression patterns during level walking, suggesting the risk of the locomotors subjecting to abnormal loading during daily walking. Education and conservative interventions might be needed for preservation of medical outcome and prevention of back pain and/or musculoskeletal consequences later in the lives of AIS with and without surgical correction.


Assuntos
Escoliose/fisiopatologia , Caminhada , Adolescente , Pé/patologia , Pé/fisiopatologia , Humanos , Escoliose/patologia , Coluna Vertebral/patologia , Coluna Vertebral/fisiopatologia
20.
World Neurosurg ; 126: e330-e341, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30822594

RESUMO

BACKGROUND: The postoperative infection rates for transforaminal lumbar interbody fusion (TLIF) have ranged from <2% to 4%. However, no consensus has been reached on the treatment strategies. TLIF cage preservation or revision surgery for lumbar spine reconstruction are 2 possible treatments. We aimed to determine the most effective method for organ/space infection control. METHODS: The data from 4923 patients who had undergone TLIF with cage and posterior pedicle-screw instrumentation for spondylolysis or degenerative spondylolisthesis from January 2008 to December 2015 were retrospectively analyzed. Of the 4923 patients, 32 (0.65%) had developed organ/space infection of the interbody cage and were divided into 2 groups: those whose interbody cage was removed for revision (group 1) and those who interbody cage was retained (group 2). We compared the initial management of both groups in terms of age, sex, elapsed time to diagnosis, changes in spinal lordotic angle, visual analog scale score, fusion status, and Kirkaldy-Willis functional outcomes. RESULTS: The 32 patients with organ/space infection had a mean age of 66.3 years and a follow-up period of 23.8 months. Significant differences were observed in the mean elapsed time to diagnosis (P = 0.004), lordotic angle correction at the disease level (P = 0.03), and Kirkaldy-Wallis functional outcomes (P = 0.01). Of the 17 patients undergoing debridement for implant retention, 9 (52.9%) exhibited poor results. CONCLUSIONS: The most important factor contributing to TLIF cage retention failure was epidural fibrosis of the previous transforaminal route and biofilm adhesion on interbody devices affecting infection clearance. Thus, we would recommend a combined anterior and posterior approach or the transforaminal route for radical debridement with cage removal and fusion to achieve better clinical outcomes.


Assuntos
Degeneração do Disco Intervertebral/cirurgia , Região Lombossacral/cirurgia , Infecções Relacionadas à Prótese/tratamento farmacológico , Fusão Vertebral/instrumentação , Fatores Etários , Idoso , Desbridamento , Feminino , Seguimentos , Humanos , Lordose/patologia , Masculino , Pessoa de Meia-Idade , Parafusos Pediculares , Infecções Relacionadas à Prótese/microbiologia , Reoperação , Estudos Retrospectivos , Fatores Sexuais , Espondilolistese/cirurgia , Espondilólise/cirurgia , Resultado do Tratamento
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