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1.
IEEE Trans Med Imaging ; PP2024 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-39250375

RESUMEN

The deep neural networks combined with the statistical shape model have enabled efficient deformable 2D-3D registration and recovery of 3D anatomical structures from a single radiograph. However, the recovered volumetric image tends to lack the volumetric fidelity of fine-grained anatomical structures and explicit consideration of cross-dimensional semantic correspondence. In this paper, we introduce a simple but effective solution for semantically-consistent deformable 2D-3D registration and detailed volumetric image recovery by inferring a voxel-wise registration field between the cone-beam computed tomography and a single lateral cephalometric radiograph (LC). The key idea is to refine the initial statistical model-based registration field with craniofacial structural details and semantic consistency from the LC. Specifically, our framework employs a self-supervised scheme to learn a voxel-level refiner of registration fields to provide fine-grained craniofacial structural details and volumetric fidelity. We also present a weakly supervised semantic consistency measure for semantic correspondence, relieving the requirements of volumetric image collections and annotations. Experiments showcase that our method achieves deformable 2D-3D registration with performance gains over state-of-the-art registration and radiograph-based volumetric reconstruction methods. The source code is available at https://github.com/Jyk-122/SC-DREG.

2.
BMB Rep ; 57(6): 287-292, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38523373

RESUMEN

Hepatocellular Carcinoma (HCC), the predominant primary hepatic malignancy, is the prime contributor to mortality. Despite the availability of multiple surgical interventions, patient outcomes remain suboptimal. Immunotherapies have emerged as effective strategies for HCC treatment with multiple clinical advantages. However, their curative efficacy is not always satisfactory, limited by the dysfunctional T cell status. Thus, there is a pressing need to discover novel potential biomarkers indicative of T cell exhaustion (Tex) for personalized immunotherapies. One promising target is Cyclin-dependent kinase inhibitor 2 (CDKN2) gene, a key cell cycle regulator with aberrant expression in HCC. However, its specific involvement remains unclear. Herein, we assessed the potential of CDKN2 expression as a promising biomarker for HCC progression, particularly for exhausted T cells. Our transcriptome analysis of CDKN2 in HCC revealed its significant role involving in HCC development. Remarkably, single-cell transcriptomic analysis revealed a notable correlation between CDKN2 expression, particularly CDKN2A, and Tex markers, which was further validated by a human cohort study using human HCC tissue microarray, highlighting CDKN2 expression as a potential biomarker for Tex within the intricate landscape of HCC progression. These findings provide novel perspectives that hold promise for addressing the unmet therapeutic need within HCC treatment. [BMB Reports 2024; 57(6): 287-292].


Asunto(s)
Biomarcadores de Tumor , Carcinoma Hepatocelular , Neoplasias Hepáticas , Linfocitos T , Humanos , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/inmunología , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/inmunología , Biomarcadores de Tumor/metabolismo , Biomarcadores de Tumor/genética , Linfocitos T/metabolismo , Linfocitos T/inmunología , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Agotamiento de Células T
3.
Cancers (Basel) ; 15(16)2023 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-37627211

RESUMEN

HCC is a major contributor to cancer-related mortality worldwide. Curative treatments are available for a minority of patients diagnosed at early stages; however, only a few multikinase inhibitors are available and are marginally effective in advanced cases, highlighting the need for novel therapeutic targets. One potential target is the protein arginine methyltransferase, which catalyzes various forms of arginine methylation and is often overexpressed in various cancers. However, the diverse expression patterns and clinical values of PRMTs in HCC remain unclear. In the present study, we evaluated the transcriptional expression of PRMTs in HCC cohorts using publicly available datasets. Our results revealed a significant association between PRMTs and prognosis in HCC patients with diverse clinical characteristics and backgrounds. This highlights the promising potential of PRMTs as prognostic biomarkers in patients with HCC. In particular, single-cell RNA (scRNA) sequencing analysis coupled with another human cohort study highlighted the pivotal role of PRMT1 in HCC progression, particularly in the context of Tex. Translating these findings into specific therapeutic decisions may address the unmet therapeutic needs of patients with HCC.

4.
Front Pediatr ; 10: 977866, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36507138

RESUMEN

The coronoid process of the ulna, as a key part of the elbow joint, plays an important role in maintaining elbow joint stability. Reconstruction of the coronoid process is necessary in both acute and chronic coronoid defects to restore elbow stability and avoid early joint degeneration. The olecranon tip may be a useful autologous osteochondral graft for reconstructing the same shape of the ulna coronoid process. The purpose of this report was to verify if reconstruction of the coronoid process with the olecranon tip can restore elbow stability and kinematics. Here, we report a 13-year-old boy who had undergone Kirschner-wire fixation for a left supracondylar fracture of the left humerus 9 years previously. After that, the right elbow dislocation and varus deformity gradually appeared. Imaging revealed posterolateral dislocation of the left elbow due to the absence of the coronoid process of the ulna. We reconstructed the ulnar coronoid process by intercepting the ipsilateral olecranon tip. After 22 months of follow-up, the range of motion of the left elbow joint was normal, and the cubitus varus deformity disappeared. The results of this report suggest that olecranon tip autografts are suitable to replace transverse coronoid defects. Given the patient's satisfactory clinical results, this reconstruction technique is safe and effective for the treatment of chronic elbow instability due to coronoid process defects of the ulna.

5.
Front Surg ; 9: 960541, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36189382

RESUMEN

Background: Proximal humeral fractures (PHFs) are rare in children. Currently, the recommended surgical methods for severely displaced PHFs are closed reduction and percutaneous fixation using K-wires or intramedullary nailing, which can't provide firm internal fixation, especially for older and high-weight children. This study aimed to introduce a novel surgical approach, pediatric physeal slide-traction plate fixation (PPSP), for Neer-Horwitz grade IV PHFs in children. Case summary: A 9-year-old boy presented with left shoulder pain and swelling due to a car accident. Physical examination revealed a positive shoulder deformity and local tenderness. On physical examination, we palpated bone friction without vascular and nerve damage. Based on imaging findings, we diagnosed Neer-Horwitz grade IV PHF. In view of the patient's condition, we performed PPSP after careful communication with the patient's parents. After 22 months of follow-up, the patient's left shoulder function was satisfactory, and there was no restriction of activities. Conclusion: According to previous studies, PPSP is only used for femur fractures. To the best of our knowledge, this is the first in the treatment for PHFs. Given the satisfactory outcomes, it is a safe and effective method and may provide a reference to cure analogous patients in the future.

6.
J High Energy Phys ; 2021(10): 201, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34725539

RESUMEN

Progress in identifying the bulk microstate interpretation of the Ryu-Takayanagi formula requires understanding how to define entanglement entropy in the bulk closed string theory. Unfortunately, entanglement and Hilbert space factorization remains poorly understood in string theory. As a toy model for AdS/CFT, we study the entanglement entropy of closed strings in the topological A-model in the context of Gopakumar-Vafa duality. We will present our results in two separate papers. In this work, we consider the bulk closed string theory on the resolved conifold and give a self-consistent factorization of the closed string Hilbert space using extended TQFT methods. We incorporate our factorization map into a Frobenius algebra describing the fusion and splitting of Calabi-Yau manifolds, and find string edge modes transforming under a q-deformed surface symmetry group. We define a string theory analogue of the Hartle-Hawking state and give a canonical calculation of its entanglement entropy from the reduced density matrix. Our result matches with the geometrical replica trick calculation on the resolved conifold, as well as a dual Chern-Simons theory calculation which will appear in our next paper [1]. We find a realization of the Susskind-Uglum proposal identifying the entanglement entropy of closed strings with the thermal entropy of open strings ending on entanglement branes. We also comment on the BPS microstate counting of the entanglement entropy. Finally we relate the nonlocal aspects of our factorization map to analogous phenomenon recently found in JT gravity.

7.
World J Clin Cases ; 9(25): 7478-7483, 2021 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-34616815

RESUMEN

BACKGROUND: Forearm crisscross injury is rare in children; there is no relevant literature so far. Surgeons lack experience and knowledge in treating this type of crisscross injury. We report a case of forearm crisscross injury in a child for the first time and analyze its mechanism. CASE SUMMARY: An 8-year-old boy experienced pain in his left forearm when he accidentally fell while skateboarding. Physical examination revealed swelling and deformity of the left forearm. We performed imaging and the results revealed left radial head dislocation, left distal radial epiphyseal separation from the shaft, and interruption of the continuity of the dorsal cortex of the left distal ulna. Anteroposterior and lateral X-ray films showed that the radius and ulna were crisscrossed. A diagnosis of superior radioulnar joint dislocation, left distal radial epiphyseal injury, and left distal ulnar fracture was made. After unsuccessful manual reduction, we adopted a minimally invasive procedure and succeeded. After a 14-wk period of follow-up, the patient had good left upper limb function, no complaints of pain or limited range of motion, and good follow-up results. CONCLUSION: This is the first report of a child with a forearm crisscross injury in which the mechanism and the differences from adult crisscross injury are analyzed. Minimally invasive surgery with intramedullary fixation can achieve a good therapeutic effect. This case provides a reference for the treatment of similar patients in the future.

8.
Int J Nanomedicine ; 16: 6693-6718, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34621123

RESUMEN

PURPOSE: Insufficient biological activity heavily restricts the application and development of biodegradable bone implants. Functional modification of bone implants is critical to improve osseointegration and bone regeneration. METHODS: In this study, L-lysine functionalized graphene oxide (Lys-g-GO) nanoparticles and polydopamine-assisted gold nanoparticle (AuNPs-PDA) coatings were applied to improve the biological function of PLGA scaffold materials. The effects of Lys-g-GO nanoparticles and AuNPs-PDA functionalized coatings on the physicochemical properties of PLGA scaffolds were detected with scanning electron microscopy (SEM), contact angle measurement, and mechanical testing instruments. In vitro, the effects of composite scaffolds on MC3T3-E1 cell proliferation, adhesion, and osteogenic differentiation were studied. Finally, a radial defect model was used to assess the effect of composite scaffolds on bone defect healing. RESULTS: The prepared AuNPs-PDA@PLGA/Lys-g-GO composite scaffolds exhibited excellent mechanical strength, hydrophilicity and antibacterial properties. In vitro, this composite scaffold can significantly improve osteoblast adhesion, proliferation, osteogenic differentiation, calcium deposition, and other cell behaviour. In vivo, this composite scaffold can significantly promote the new bone formation and collagen deposition in the radial defect site and presented good biocompatibility. CONCLUSION: The combination of bioactive nanoparticles and surface coatings shows considerable potential to enhance the osseointegration of bone implants.


Asunto(s)
Nanopartículas del Metal , Osteogénesis , Regeneración Ósea , Oro , Grafito , Lisina , Ingeniería de Tejidos , Andamios del Tejido
9.
Breast Cancer ; 28(4): 806-821, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33475963

RESUMEN

BACKGROUND: MicroRNA-155 (miR-155) may function as a diagnostic biomarker of breast cancer (BC). Nevertheless, the available evidence is controversial. Therefore, we performed this study to summarize the global predicting role of miR-155 for early detection of BC and preliminarily explore the functional roles of miR-155 in BC. METHODS: We first collected published studies and applied the bivariate meta-analysis model to generate the pooled diagnostic parameters of miR-155 in diagnosing BC such as sensitivity, specificity and area under curve (AUC). Then, we applied function enrichment and protein-protein interactions (PPI) analyses to explore the potential mechanisms of miR-155. RESULTS: A total of 21 studies were finally included. The results indicated that miR-155 allowed for the discrimination between BC patients and healthy controls with a sensitivity of 0.87 (95% CI 0.78-0.93), specificity of 0.82 (0.72-0.89), and AUC of 0.91 (0.88-0.93). In addition, the overall sensitivity, specificity and AUC for circulating miR-155 were 0.88 (0.76-0.95), 0.83 (0.72-0.90), and 0.92 (0.89-0.94), respectively. Function enrichment analysis revealed several vital ontologies terms and pathways associated with BC occurrence and development. Furthermore, in the PPI network, ten hub genes and two significant modules were identified to be involved in some important pathways associated with the pathogenesis of BC. CONCLUSIONS: We demonstrated that miR-155 has great potential to facilitate accurate BC detection and may serve as a promising diagnostic biomarker for BC. However, well-designed cohort studies and biological experiments should be implemented to confirm the diagnostic value of miR-155 before it can be applied to routine clinical procedures.


Asunto(s)
Biomarcadores de Tumor/sangre , Neoplasias de la Mama/diagnóstico , MicroARNs/sangre , Área Bajo la Curva , Biomarcadores de Tumor/genética , Neoplasias de la Mama/sangre , Neoplasias de la Mama/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , MicroARNs/genética , Persona de Mediana Edad , Mapas de Interacción de Proteínas
10.
Front Med (Lausanne) ; 7: 577578, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33425934

RESUMEN

Recent evidence has demonstrated that mesenchymal stem cells (MSCs) can release a large number of functionally specific microRNA (miRNA) microvesicles that play a role in promoting osteogenic differentiation, but the specific mechanism is not yet clear. Under such context, this study aims to elucidate the mechanism of bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exo) promoting fracture healing in mice. We isolated and identified the BMSC-Exo. Bioinformatics analysis predicted high expression of miRNA in exosomes and verified the transfer of miR-25 in exosomes by immunofluorescence. Targeting relationship between miR-25 and Smad ubiquitination regulatory factor-1 (SMURF1) was predicted and verified by dual-luciferase reporter gene assay. Immunoprecipitation and protein stability assays were used to detect Runt-related transcription factor 2 (Runx2) ubiquitination and the effect of SMURF1 on Runx2 ubiquitination, respectively. The effect of miR-25 in BMSC-Exo on fracture healing in mice was assessed using X-ray imaging. alkaline phosphatase, alizarin red staining, EdU, CCK-8, and Transwell were used to evaluate the effects of exosomes transferred miR-25 on osteogenic differentiation, proliferation, and migration of osteoblasts. Bioinformatics analysis predicted that miR-25 expression in exosomes increased significantly. Moreover, the targeted regulation of SMURF1 by miR-25 was verified. SMURF1 inhibited Runx2 protein expression by promoting ubiquitination degradation of Runx2. Notably, miR-25 secreted by BMSC-Exo can accelerate osteogenic differentiation, proliferation, and migration of osteoblasts through SMURF1/Runx2 axis. Our results demonstrate that miR-25 in BMSC-Exo regulates the ubiquitination degradation of Runx2 by SMURF1 to promote fracture healing in mice.

11.
Medicine (Baltimore) ; 98(22): e15547, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-31145275

RESUMEN

RATIONALE: In this paper, the efficacy and safety of using navigated drilling and arthroscopy (NDA) to assist surgery for ulnar-radial joint dislocation caused by epiphyseal premature closure (EPC) are described. Deformity correction surgery was mentioned in the literature, but there were numerous complications, for example, poor correction, infection, neurovascular injury, osteofascial compartment syndrome, failure of internal fixation, and nonunion after osteotomy. In order to minimize surgical complications, we utilized navigated drilling to finish accuracy bone bridge resection and applied arthroscopy to assess wrist lesions. PATIENT CONCERNS: An 11-year-old male patient showed swelling and pain of the left wrist. DIAGNOSES: The patient was diagnosed with a postoperative of Kirschner wire internal fixation for epiphyseal injury, left lower ulnar-radial joint dislocation, left wrist deformity, and EPC. INTERVENTIONS: A NDA was used to assist the bone bridge resection in this patient. OUTCOMES: Pain was relieved clearly in the patient. Dorsiflexion increased from 60.8° to 85.3°, palmar flexion increased from 45.3° to 65.8°, supination increased from 41.3° to 69.5°, and pronation increased from 31.6° to 62.9°. The preoperative disabilities of the arm, shoulder, and hand (DASH) score was 86.1, which was increased to 16.4 postoperatively. Surgery designing lasted for 2 minutes, bone bridge resection lasted for 56 minutes, and fluoroscopic time was 2.4 minutes. Complications, for example, neurological injury, vascular injury, infection and deformity aggressive, were not found during the 5-month follow up. LESSONS: The outcome of the present study suggests that the NDA maximizes the bone bridge resection accuracy in EPC treatment, which is made efficient by reducing surgical trauma and avoiding neurovascular injury. An experience was gained that in the process of bone bridge removal, the bit of navigated drill should be continuously washed with normal saline to cool down, so as to avoid damage of nerve caused by heat conduction.


Asunto(s)
Artroplastia Subcondral/métodos , Artroscopía/métodos , Enfermedades del Desarrollo Óseo/complicaciones , Placa de Crecimiento , Luxaciones Articulares/cirugía , Niño , Humanos , Luxaciones Articulares/etiología , Masculino , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Radio (Anatomía)/anomalías , Radio (Anatomía)/cirugía , Cúbito/anomalías , Cúbito/cirugía
12.
Medicine (Baltimore) ; 98(21): e15591, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-31124935

RESUMEN

RATIONALE: The aim of the present study was to assess the efficacy and safety of percutaneous cannulated screw (PCS) implantation assisted by screw view model of navigation (SVMN) to treat femoral neck fracture (FNF). PATIENT CONCERNS: A 42-year-old male patient suffered from a high falling injury, causing pain, swelling, deformity, and limited mobility on his right hip. DIAGNOSES: He was diagnosed with Garden type I of FNF. INTERVENTIONS: PCS implantation assisted by SVMN was used to treat fracture of femoral neck in this patient. OUTCOMES: The follow up lasted for 48 months. A total of 3 screws were inserted into femoral neck, all exhibiting excellent position. The mean screw deviation was 0.43° and 5.73° of femoral neck-shaft and anteversion angle, respectively. The guide wire drilling attempt of each screw was one-time. The fluoroscopic time lasted 6.3 minutes, the Harris hip scores improved from 67 to 88, and the blood loss was 35 mL. It took 11.7 minutes for designing the screws, 13.9 minutes for implanting the guide wires, and 37.3 minutes for placing the screws. No clinical complications were found during 48-month follow-up visit, including head penetration, implant failure, fracture nonunion, and femoral head osteonecrosis. LESSONS: The study revealed that SVMN is conducive to the PCS insertion for FNF. Our lesson is that the FNF must be well reduction before SVMN assisted PCS placement.


Asunto(s)
Tornillos Óseos , Fracturas del Cuello Femoral/cirugía , Fijación Interna de Fracturas/instrumentación , Neuronavegación/métodos , Adulto , Cánula , Cuello Femoral/lesiones , Cuello Femoral/cirugía , Fijación Interna de Fracturas/métodos , Curación de Fractura , Humanos , Masculino , Resultado del Tratamiento
13.
Opt Lett ; 40(23): 5530-3, 2015 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-26625043

RESUMEN

We demonstrate that a lateral optical force (LOF) can be induced on paired chiral nanoparticles with opposite handedness under the illumination of a linearly polarized plane wave. The LOFs on both chiral particles are equal and thus can move the pair sideways, with the direction depending on the separation between two particles, as well as the handedness of particle chirality. Analytical theory reveals that the LOF comes largely from the optical potential gradient established by the multiple scattering of light between the paired particles with asymmetric chirality. In addition, it is weakly dependent on the material loss of a particle, a feature of gradient force, while heavily dependent on the magnitude and handedness of particle chirality. The effect is expected to find applications in sorting and separating chiral dimers of different handedness.


Asunto(s)
Nanopartículas/química , Fenómenos Ópticos , Dimerización , Modelos Lineales , Modelos Moleculares , Conformación Molecular , Estereoisomerismo
14.
J Clin Neurosci ; 21(7): 1196-204, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24674700

RESUMEN

The traditional approach for cervical intramedullary lesions is laminectomy, but the procedure may result in spinal instability and spinal deformity. Unilateral multilevel interlaminar fenestration (UMIF) is an alternative minimally invasive approach that may have great advantages in preserving spinal stability. However its use in cervical intramedullary lesions is rare, and the indications, safety and limitations of this approach for cervical intramedullary lesions are still under investigation. We report five patients (three males, two females, age range 12-46 years) who were treated between 2010 and 2011 for cervical intramedullary lesions. The lesions included three ependymomas, one astrocytoma and one ependymal cyst, and the locations of the lesions were at the medulla-T2, C4-T1, C5-C7, C4-C7 and C6-C7. All of these lesions were completely removed through UMIF, and all patients had stable or improved neurological status after surgery. No recurrences or spinal deformities were detected during the follow-up period which ranged from 24 to 35 months (mean=27.4 months). UMIF is a feasible approach for selected cervical intramedullary lesions. This approach allows complete resection of multilevel lesions without increasing the risk of injury to the spinal cord, and minimizing the risk of postoperative spinal instability. The indications for and limitations of UMIF are discussed.


Asunto(s)
Lateralidad Funcional/fisiología , Laminectomía/métodos , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Neoplasias de la Médula Espinal/cirugía , Adolescente , Adulto , Femenino , Estudios de Seguimiento , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento , Adulto Joven
15.
CNS Neurosci Ther ; 20(2): 131-9, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24279505

RESUMEN

INTRODUCTION: Primary filum terminale ependymoma (PFTE) is a unique type of ependymomas and locates on extramedullary site. However, the clinical features and prognostic factors of PFTE are still unknown due to its rarity. AIM: This study aimed to evaluate the clinical features, outcomes, and prognostic factors of PFTE in the largest series of cases. RESULT: Thirty-eight patients were included in this study. Gross total removal (GTR) of the tumors was achieved in 33(87%) patients. Five (13%) patients had subtotal resection (STR). For the residual tumors, postoperative radiotherapy increased the interval between the first surgery and tumor regrowth (P = 0.063). Six patients had local recurrence/progression. Univariate analysis identified STR(P = 0.001), unencapsulated tumor (P = 0.018), tumor involving more than two vertebral columns (P = 0.005), and tumor invading sacral canal(P < 0.001) as predictors of tumor recurrence. In addition, 36 (95%) patients had stable or improved neurological status directly after surgery. Klekamp-Samii score was better correlated with the symptoms than McCormick scale. CONCLUSION: Extent of surgical removal, tumor size, tumor location, and the integrity of tumor capsule are the prognostic factors of PFTEs, and the intrasacral PFTEs always have a poor prognosis.


Asunto(s)
Cauda Equina/patología , Ependimoma/diagnóstico , Ependimoma/cirugía , Neoplasias del Sistema Nervioso Periférico/diagnóstico , Neoplasias del Sistema Nervioso Periférico/cirugía , Adolescente , Adulto , Análisis de Varianza , Ependimoma/mortalidad , Femenino , Estudios de Seguimiento , Humanos , Estimación de Kaplan-Meier , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Neoplasias del Sistema Nervioso Periférico/mortalidad , Estudios Retrospectivos , Resultado del Tratamiento , Adulto Joven
16.
Eur Spine J ; 22(12): 2719-30, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24013720

RESUMEN

PURPOSE: The objective of this study was to investigate the impact of the less invasive procedures of hemilaminectomy and unilateral multilevel interlaminar fenestration (UMIF) on the cervical spinal biomechanics. METHODS: A validated nonlinear finite element model of the intact cervical spine (C2-C7) was modified to study the biomechanical changes as a result of surgical alteration for treatment of intradural tumours at C3-6 using multilevel laminectomy (ML), multilevel hemilaminectomy (MHL) and UMIF with or without unilateral graded facetectomy. RESULTS: Under the load-controlled method, the greatest biomechanical changes occurred at the surgical segments. The largest increases occurred in flexion motions following ML approach with 70, 62 and 60 % increase at C3-4, C4-5 and C5-6, respectively. The increases were significantly reduced to no more than 14 % under MHL and UMIF. When combined with graded facetectomy, the changes in flexion under ML approach have a significantly further increase, up to 110 % at C3-4. The further increase was not significantly following MHL and UMIF, with no more than 31 % increase at C3-4, C4-5 and C5-6. The motion following UMIF was only slightly smaller in axial rotation than MHL. The maximum stresses in the annulus occurred during flexion in ML model, with 39, 34 and 38 % more stress than the intact at C3-4, C4-5 and C5-6, respectively. The increases of stress were significantly reduced to 5-7 % under MHL and UMIF. CONCLUSIONS: The less invasive approaches of UMIF and MHL greatly preserved the flexion motion (more than 48 %) of the cervical spine compared with laminectomy, and the preserved motion mean the low-risk of postoperative spinal instability. UMIF and MHL also reduced the increased stress of annulus caused by ML, and the lesser stress will lower the risk of postoperative disc degeneration. The posterior bone elements play a slight role in spinal stability after removal of the attached ligaments.


Asunto(s)
Vértebras Cervicales/cirugía , Análisis de Elementos Finitos , Laminectomía/métodos , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Modelos Biológicos , Neoplasias de la Médula Espinal/cirugía , Neoplasias de la Columna Vertebral/cirugía , Fenómenos Biomecánicos , Vértebras Cervicales/fisiopatología , Humanos , Inestabilidad de la Articulación/etiología , Inestabilidad de la Articulación/cirugía , Rango del Movimiento Articular , Rotación , Neoplasias de la Columna Vertebral/complicaciones
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