Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
1.
Bull Menninger Clin ; 85(3): 254-270, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34468214

RESUMO

Sleep problems among frontline medical staff during the COVID-19 epidemic require attention. A total of 249 frontline medical staff who were recruited to support Wuhan completed this cross-sectional study. A web-based questionnaire about insomnia, depression, anxiety, and fatigue was used to assess mental health status. The prevalence of sleep disorders among frontline medical staff was 50.6%. More time spent in Wuhan and a history of insomnia, depression, anxiety, and fatigue were associated with a higher risk of insomnia. People who stayed in Wuhan for a long time with a history of insomnia, depression, anxiety, and fatigue symptoms might be at high risk of insomnia.


Assuntos
Adaptação Psicológica , COVID-19/psicologia , Corpo Clínico Hospitalar/psicologia , Transtornos Mentais/epidemiologia , Transtornos do Sono-Vigília/epidemiologia , Adulto , China , Comorbidade , Estudos Transversais , Feminino , Humanos , Masculino , Corpo Clínico Hospitalar/estatística & dados numéricos , Transtornos Mentais/psicologia , SARS-CoV-2 , Transtornos do Sono-Vigília/psicologia , Estresse Psicológico/epidemiologia , Estresse Psicológico/psicologia , Inquéritos e Questionários , Fatores de Tempo
2.
Int J Numer Method Biomed Eng ; 37(8): e3498, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33998776

RESUMO

Lumbar spinal fusion may cause adjacent segment degeneration (ASD) in the long term. Recently, inserting an interspinous process device (IPD) proximal to the fusion has been proposed to prevent ASD. The aim of this study was to investigate the biomechanics of lumbar fusion with proximal IPD implantation (LFPI) under both static loads and whole body vibration (WBV). A previously validated finite element (FE) model of the L1-5 lumbar spine was modified to simulate L4-5 fusion. Three different IPDs (Coflex-F, Wallis and DIAM) were inserted at the L3-4 segment of the fusion model to construct the LFPI models. The intact and surgical FE models were analyzed under static loads and WBV, respectively. Under static loading conditions, LFPI decreased range of motion (ROM) and intradiscal pressure (IDP) at the transition segment L3-4 compared with the fusion case. At the segment (L2-3) adjacent to the transition level, LFPI induced higher motion and IDP than rigid fusion. Under WBV, vibration amplitudes of the L3-4 IDP and L4-5 facet joint force (FJF) decreased by more than 54.3% after surgery. The LFPI model with the DIAM system offered the most comparable biomechanics to the intact model under static loads, and decreased the dynamic responses of the L4-5 FJF under WBV. The LFPI model with the Wallis and Coflex-F systems could stabilize the transition segment, and decrease dynamic responses of the L3-4 IDP. The DIAM system may be more suitable in LFPI.

3.
Bull Menninger Clin ; : 1-17, 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-33939498

RESUMO

Sleep problems among frontline medical staff during the COVID-19 epidemic require attention. A total of 249 frontline medical staff who were recruited to support Wuhan completed this cross-sectional study. A web-based questionnaire about insomnia, depression, anxiety, and fatigue was used to assess mental health status. The prevalence of sleep disorders among frontline medical staff was 50.6%. More time spent in Wuhan and a history of insomnia, depression, anxiety, and fatigue were associated with a higher risk of insomnia. People who stayed in Wuhan for a long time with a history of insomnia, depression, anxiety, and fatigue symptoms might be at high risk of insomnia.

4.
Clin Biomech (Bristol, Avon) ; 84: 105339, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33780788

RESUMO

BACKGROUND: Anterior lumbar interbody fusion combined with supplementary fixation has been widely used to treat lumbar diseases. However, few studies have investigated the influence of fixation options on facet joint force and cage subsidence. The aim of this study was to explore the biomechanical performance of anterior lumbar interbody fusion with various fixation options under both static and vertical vibration loading conditions. METHODS: A previously validated finite element model of the intact L1-5 lumbar spine was employed to compare five conditions: (1) Intact; (2) Fusion alone; (3) Fusion combined with anterior lumbar plate; (4) Fusion combined with Coflex-F fixation; (5) Fusion combined with bilateral pedicle screw fixation. The models were analyzed under static and vertical vibration loading conditions respectively. FINDINGS: Bilateral pedicle screws provided highest stability at surgical level. Applying supplementary fixation diminished the dynamic responses of lumbar spine. Compared with anterior lumbar plate and Coflex-F device, bilateral pedicle screws decreased the stress responses of the endplates and cage under both static and vibration conditions, while increased the facet joint force at adjacent levels. As for comparison between Coflex-F device and anterior lumbar plate, results showed a similarity in biomechanical performance under static loading, and a slightly higher dynamic response of the latter under vertical vibration. INTERPRETATION: The biomechanical performance of lumbar spine was significantly influenced by the variation of fixations under both static and vibration conditions. Bilateral pedicle screws showed advantages in stabilizing surgical segment and relieving cage subsidence, but may increase the facet joint force at adjacent levels.

5.
J Cogn Psychother ; 2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-33397786

RESUMO

Family accommodation is a phenomenon that has been associated with worse treatment outcome of patients with obsessive-compulsive disorder (OCD) and greater severity of symptoms and levels of functional impairment. Yet, there are no Chinese scales to assess family accommodation in OCD among family members. The present study aimed to illustrate the steps of translation and cross-cultural adaptation of the Chinese versions of the Family Accommodation Scale (FAS). After obtaining authorization of the developers, the Chinese versions of the FAS were translated and adapted from the English versions based on a standard protocol, following six steps: forward translation, pilot administration, language adjustment and cultural adaptation, back-translation, review and minor edit, and final approval of the developer. Thirty-five pairs of patients and corresponding relatives with different education levels were administered the FAS in the pretest stage. This study found that the semantic, idiomatic, and conceptual equivalence were obtained between the Chinese versions and original English scales, and the Chinese versions of FAS were well translated and culturally adapted. We also found that the Chinese versions of the FAS can be easily understood by people of different socioeconomic statuses.

6.
Compr Psychiatry ; 105: 152220, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33348295

RESUMO

BACKGROUND: Family accommodation (FA) in obsessive-compulsive disorder (OCD) means that the relatives of patients are involved in, help or facilitate patients' ritual behaviors and avoidance, which is a frequent occurrence and underresearched phenomenon in China. Recent studies have suggested that FA is adversely associated with treatment response, contradictory to the goal of cognitive behavior therapy, a contributor to the maintenance of symptoms and increased symptom severity, and associated with low levels of family and social functioning. There is increasing interest and focus on establishing a family-based intervention for OCD treatment based on the inclusion of relatives by decreasing FA. The present study explored the psychometric properties of the Chinese version of the Family Accommodation Scale for OCD Interviewer-Rated (FAS-IR). METHOD: A total of 109 patients with OCD and 91 primary relatives were assessed in corresponding patient and family measures, and the FAS-IR was administered to relatives by trained interviewers. RESULTS: More than 90% of the relatives accommodated patients' symptoms with at least one kind of FA behavior over the previous week, and the incidence of extreme or everyday routines was as high as 59.3%. Exploratory factor analysis demonstrated two-factor structure for the whole scale, including (1) modification and facilitation, and (2) participation. Cronbach's alpha was 0.798 for the whole scale, and the interrater and test-retest reliability coefficients were 0.835 (95%CI: 0.603-0.937) and 0.882 (95%CI: 0.685-0.959), respectively. Convergent validity was supported in exploring FA and was associated with symptom severity, level of functional impairment and family functioning related to OCD. The FA was not significantly correlated with depressive symptoms rated by the patients, as evidence of acceptable divergent validity. There was no significant difference in FA total score based on patient gender, patient age, or relationship with patients. CONCLUSIONS: The Chinese version of the FAS-IR demonstrated excellent psychometric properties for assessing the degree of FA, suggesting that it is a useful and valuable instrument in clinical and research settings.


Assuntos
Transtorno Obsessivo-Compulsivo , China , Análise Fatorial , Família , Humanos , Transtorno Obsessivo-Compulsivo/diagnóstico , Psicometria , Reprodutibilidade dos Testes
7.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 37(3): 527-532, 2020 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-32597096

RESUMO

Total lumbar disc replacement is an alternative to interbody fusion for the effective treatment of symptomatic degenerative disc disease. This paper reviewed the history of ball-on-socket type artificial lumbar disc (ALD) prosthesis, which is a typical ALD prosthesis and summarized the ALD prosthesis research progress, according to different materials such as metal-on-metal, metal-on-polymer, and polymer-on-polymer prosthesis. The structural design factors of ball-on-socket type ALD prosthesis were analyzed and its prospect of development was also presented. The purpose of this paper is to provide a theoretical reference for the design of the ball-on-socket ALD prosthesis by reviewing the current state of ball-on-socket type ALD prosthesis.


Assuntos
Degeneração do Disco Intervertebral , Disco Intervertebral , Implantação de Prótese , Substituição Total de Disco , Simulação por Computador , Humanos , Degeneração do Disco Intervertebral/cirurgia , Vértebras Lombares , Resultado do Tratamento
8.
World Neurosurg ; 127: e1112-e1119, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30980982

RESUMO

BACKGROUND: Recently, interspinous stabilization with the interspinous process device (IPD) has become an alternative to treat lumbar spinal stenosis. The biomechanical influence of different design features of IPDs on intradiscal pressure (IDP) and facet joint force (FJF) has not been fully understood. The aim of this study was to investigate the biomechanical performance of different IPDs using finite element (FE) method. METHODS: A FE model of the L1-5 segments was developed and validated. Four surgical FE models were constructed by inserting different implants at the L3-4 segment (Coflex-F, DIAM, Wallis, and pedicle screw system). The 4 motion modes were simulated. RESULTS: The IPDs decreased range of motion (ROM) at the surgical level substantially in flexion and extension, but little influence was found in lateral bending and torsion. Compared with the DIAM and Wallis devices, the Coflex-F device showed advantages in stabilizing the surgical level, especially in flexion and extension, while it increased FJF at adjacent levels by 26%-27% in extension. Among the 3 IPDs, the DIAM device exhibited the most comparable ROM, IDP, and FJF at adjacent levels compared with the intact lumbar spine. The influence of the Wallis device was between that of the Coflex-F and DIAM devices. CONCLUSIONS: Compared with rigid fixation, the IPDs demonstrated less compensation at adjacent levels in terms of ROM, IDP, and FJF, which may lower the incidence of adjacent segment degeneration in the long term.


Assuntos
Análise de Elementos Finitos , Imageamento Tridimensional/métodos , Vértebras Lombares/anatomia & histologia , Vértebras Lombares/fisiologia , Modelos Anatômicos , Fusão Vertebral/instrumentação , Adulto , Fenômenos Biomecânicos/fisiologia , Feminino , Humanos , Vértebras Lombares/cirurgia , Parafusos Pediculares , Fusão Vertebral/métodos
9.
ACS Biomater Sci Eng ; 5(5): 2409-2416, 2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-33405749

RESUMO

Interbody fusion surgery is often used to settle matters such as degenerative disc disease or disc herniation in clinical orthopedics. Considering the deficiencies of the current treatment methods, we developed an interbody fusion cage made of calcium silicate (CS)/polyetheretherketone (PEEK) and hoped that the bioactive cage could exhibit great fusion ability and maintain stable mechanical function. In the goat model of cervical interbody fusion, the CS/PEEK cage showed stronger interbody fusion at 12 and 26 weeks compared with pure PEEK cage based on the X-ray analysis. The micro-CT scanning and analysis indicated that the CS/PEEK cage induced more new bone ingrowth than the PEEK cage and led to nearly complete interbody fusion at 26 weeks. Moreover, the CS/PEEK group showed excellent mechanical stability and stiffness as evaluated by the spine kinematic assay at the time points. The histological assessment showed the rapid osseointegration and mineralized bone formation around the CS/PEEK cage. This study confirmed that the bioactive CS/PEEK cage is capable of inducing highly effective bone fusion and has high potential to be used in the clinics of spine surgery.

10.
Biomed Mater Eng ; 29(4): 485-497, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30282345

RESUMO

BACKGROUND: Lumbar spinal fusion in the interbody space is augmented with interbody fusion cages to provide structural support while arthrodesis occurs. Subsidence is a serious complication of interbody fusion. However, the biomechanical influence of anterior longitudinal ligament (ALL) and pedicle screws on subsidence has not been fully understood. OBJECTIVE: To investigate biomechanical effects of the hyperlordotic cages in different surgical conditions using finite element analysis. METHODS: Four surgical finite element (FE) models were constructed by inserting 15 degree lordosis cage at the L3-L4 disc space. The four surgical conditions were ALL intact (M1), ALL resected (M2), ALL intact and bilateral pedicle screws (M3), and ALL resected and bilateral pedicle screws (M4). Follow loads were applied at the L2 vertebral body while the inferior surface of L5 was fixed. FEA was implemented to simulate the four motion modes and biomechanical properties of four fusion scenarios with hyperlordotic interbody cage were compared. RESULTS: The range of motion (ROM) and facet joint force (FJF) at L3-L4 decreased significantly after fusion during all the motion modes. The cage stress and endplate stress at L3-L4 increased significantly after fusion during all the motion modes. The cage stress and endplate stress at L3-L4 for M3 and M4 were smaller than that for M1 and M2 during all the motion modes. The FJF at L3-L4 for M3 and M4 were smaller than that for M1 and M2 during extension, bending, and rotation. CONCLUSIONS: ALL has little effect on the biomechanics after lumbar fusion with hyperlordotic interbody cage. The bilateral pedicle screws significantly decreased the stress in cage, stress in endplate at L3-L4, and lowered facet contact force except for flexion mode. The implication is that the supplemental bilateral pedicle screws are recommended whether or not the ALL is resected.


Assuntos
Análise de Elementos Finitos , Parafusos Pediculares , Medula Espinal/cirurgia , Fusão Vertebral/métodos , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Lordose/terapia , Vértebras Lombares/cirurgia , Modelos Anatômicos
11.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 35(3): 493-500, 2018 06 25.
Artigo em Chinês | MEDLINE | ID: mdl-29938961

RESUMO

The mechanical properties of artificial intervertebral disc (AID) are related to long-term reliability of prosthesis. There are three testing methods involved in the mechanical performance evaluation of AID based on different tools: the testing method using mechanical simulator, in vitro specimen testing method and finite element analysis method. In this study, the testing standard, testing equipment and materials of AID were firstly introduced. Then, the present status of AID static mechanical properties test (static axial compression, static axial compression-shear), dynamic mechanical properties test (dynamic axial compression, dynamic axial compression-shear), creep and stress relaxation test, device pushout test, core pushout test, subsidence test, etc. were focused on. The experimental techniques using in vitro specimen testing method and testing results of available artificial discs were summarized. The experimental methods and research status of finite element analysis were also summarized. Finally, the research trends of AID mechanical performance evaluation were forecasted. The simulator, load, dynamic cycle, motion mode, specimen and test standard would be important research fields in the future.


Assuntos
Disco Intervertebral , Próteses e Implantes , Substituição Total de Disco , Fenômenos Biomecânicos , Análise de Elementos Finitos , Vértebras Lombares , Reprodutibilidade dos Testes , Pesquisa , Estresse Mecânico , Suporte de Carga
12.
Gait Posture ; 63: 296-301, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29807335

RESUMO

Low back pain(LBP) is one of the most prevalent diseases afflicting people today. Abnormal musculoskeletal loadings during activities of daily living (ADLs) have been deemed to be associated with spine rhythm. But no studies have reported abnormal continuous spine rhythms during ADLs in LBP patients. Therefore, the objective of this study was to investigate the continuous lumbar spine rhythms and their difference between people with and without lumbar disc herniation (LDH). Twenty-six healthy people and seven patients with LDH were recruited in this study. They performed level walking, stair climbing, and trunk flexion. Active optical markers placed on the landmark of the spinous process and pelvis were captured using motion analysis system to drive a musculoskeletal model to calculate the continuous lumbar spine rhythms. It was found that the lumbar spine rhythm was roughly constant throughout the analyzed cycle in both healthy people and LDH patients during trunk flexion. LDH patients displayed fluctuant lumbar spine rhythms during level walking and stair climbing and significantly higher segmental contributions of the lumbar segments in the lower lumbar region during stair climbing and trunk flexion. In conclusion, there were different compensatory responses to LDH in the continuous lumbar spine rhythms during different ADLs. This study provides a new insight into the abnormal spinal motion in LDH patients.


Assuntos
Deslocamento do Disco Intervertebral/fisiopatologia , Vértebras Lombares/fisiologia , Amplitude de Movimento Articular/fisiologia , Subida de Escada/fisiologia , Tronco/fisiopatologia , Caminhada/fisiologia , Atividades Cotidianas/classificação , Adulto , Estudos de Casos e Controles , Avaliação da Deficiência , Feminino , Humanos , Dor Lombar/classificação , Dor Lombar/fisiopatologia , Masculino , Pessoa de Meia-Idade , Valores de Referência
13.
World Neurosurg ; 116: 94-104, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29753897

RESUMO

OBJECTIVE: The aim of this study was to comprehensively compare the clinical and biomechanical efficiency of anterior cervical discectomy and fusion (ACDF) with anterior cervical disc replacement (ACDR) for treatment of multilevel cervical disc disease using a meta-analysis and systematical review. METHODS: A literature search was performed using PubMed, MEDLINE, EMBASE, and the Cochrane Library for articles published between January 1960 and December 2017. Both clinical and biomechanical parameters were analyzed. Statistical tests were conducted by Revman 5.3. Nineteen studies including 10 clinical studies and 9 biomechanical studies were filtered out. RESULTS: The pooled results for clinical efficiency showed that no significant difference was observed in blood loss (P = 0.09; mean difference [MD], 7.38; confidence interval [CI], -1.16 to 15.91), hospital stay (P = 0.33; MD, -0.25; CI, -0.76 to 0.26), Japanese Orthopaedic Association scores (P = 0.63; MD, -0.11; CI, -0.57 to 0.34), visual analog scale (P = 0.08; MD, -0.50; CI, -1.06 to 0.05), and Neck Disability Index (P = 0.33; MD, -0.55; CI, -1.65 to 0.56) between the 2 groups. Compared with ACDF, ACDR did show increased surgical time (P = 0.03; MD, 31.42; CI, 2.71-60.14). On the other hand, ACDR showed increased index range of motion (ROM) (P < 0.00001; MD, 13.83; CI, 9.28-18.39), lower rates of adjacent segment disease (ASD) (P = 0.001; odds ratio [OR], 0.27; CI, 0.13-0.59), complications (P = 0.006; OR, 0.62; CI, 0.45-0.87), and rate of subsequent surgery (P < 0.00001; OR, 0.25; CI, 0.14-0.44). As for biomechanical performance, ACDR maintained index ROM and avoided compensation in adjacent ROM and tissue pressure. CONCLUSIONS: Multilevel ACDR may be an effective and safe alternative to ACDF in terms of clinical and biomechanical performance. However, further multicenter and prospective studies should be conducted to obtain a stronger and more reliable conclusion.


Assuntos
Vértebras Cervicais/cirurgia , Discotomia/métodos , Degeneração do Disco Intervertebral/cirurgia , Deslocamento do Disco Intervertebral/cirurgia , Fusão Vertebral/métodos , Substituição Total de Disco/métodos , Fenômenos Biomecânicos/fisiologia , Discotomia/normas , Humanos , Degeneração do Disco Intervertebral/diagnóstico , Deslocamento do Disco Intervertebral/diagnóstico , Medição da Dor/métodos , Medição da Dor/normas , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto/normas , Fusão Vertebral/normas , Substituição Total de Disco/normas , Resultado do Tratamento
14.
World Neurosurg ; 114: e1302-e1309, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29627629

RESUMO

OBJECTIVE: To systematically investigate the effect of 3-level hybrid constructs on the cervical spine biomechanics based on a validated model of the C3-C7 segments. METHODS: Three hybrid constructs with 2 U-shaped dynamic cervical implants and 1 cage were simulated. The 3 constructs were 1) Cage-U-U (cage implanted at the C3-C4 level and U-shaped dynamic cervical implants implanted at the C4-C5 and C5-C6 levels), 2) U-Cage-U, and 3) U-U-Cage. Biomechanical parameters including moments, cervical motions, and stresses in the facet and implants were analyzed in flexion and extension. RESULTS: The flexion and extension motions at artificial cervical disc replacement levels increased for all hybrid constructs when compared with those of intact model. However, the maximum increase was 52% with U-U-Cage model. At the unoperated adjacent level, the maximum motion increase in extension was 23% with the U-U-Cage model. Also, the U-U-Cage and U-Cage-U model generated more than 40% increase in terms of flexion motion at the adjacent level. The facet stress at the adjacent level increased by 28%, 20%, and 39% with the Cage-U-U, U-Cage-U, and U-U-Cage models, respectively. The moments required to reach the same motion as the intact model were significantly increased. CONCLUSIONS: The study showed that the U-U-Cage model lead to more compensation in terms of motion and facet stress. Furthermore, the present results imply that when conducting the hybrid surgery, the segmental motions should be taken into account. Performing anterior cervical discectomy and fusion at the level whose motion is relatively small may decrease the compensation required at the adjacent level.


Assuntos
Vértebras Cervicais/cirurgia , Análise de Elementos Finitos , Imageamento Tridimensional/métodos , Fixadores Internos , Adulto , Vértebras Cervicais/anatomia & histologia , Vértebras Cervicais/diagnóstico por imagem , Análise de Elementos Finitos/tendências , Humanos , Imageamento Tridimensional/tendências , Fixadores Internos/tendências , Masculino , Próteses e Implantes/tendências , Amplitude de Movimento Articular/fisiologia , Fusão Vertebral/métodos , Substituição Total de Disco/métodos
15.
World Neurosurg ; 114: e1120-e1129, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29609081

RESUMO

BACKGROUND: Lateral lumbar interbody fusion using cage supplemented with fixation has been used widely in the treatment of lumbar disease. A combined fixation (CF) of lateral plate and spinous process plate may provide multiplanar stability similar to that of bilateral pedicle screws (BPS) and may reduce morbidity. The biomechanical influence of the CF on cage subsidence and facet joint stress has not been well described. The aim of this study was to compare biomechanics of various fixation options and to verify biomechanical effects of the CF. METHODS: The surgical finite element models with various fixation options were constructed based on computed tomography images. The lateral plate and posterior spinous process plate were applied (CF). The 6 motion modes were simulated. Range of motion (ROM), cage stress, endplate stress, and facet joint stress were compared. RESULTS: For the CF model, ROM, cage stress, and endplate stress were the minimum in almost all motion modes. Compared with BPS, the CF reduced ROM, cage stress, and endplate stress in all motion modes. The ROM was reduced by more than 10% in all motion modes except for flexion; cage stress and endplate stress were reduced more than 10% in all motion modes except for rotation-left. After interbody fusion, facet joint stress was reduced substantially compared with the intact conditions in all motion modes except for flexion. CONCLUSIONS: The combined plate fixation may offer an alternative to BPS fixation in lateral lumbar interbody fusion.


Assuntos
Análise de Elementos Finitos/normas , Fixadores Internos/normas , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Fusão Vertebral/instrumentação , Fusão Vertebral/normas , Adulto , Fenômenos Biomecânicos/fisiologia , Placas Ósseas/normas , Feminino , Humanos , Imageamento Tridimensional/métodos , Vértebras Lombares/fisiologia , Parafusos Pediculares/normas , Amplitude de Movimento Articular/fisiologia , Fusão Vertebral/métodos
16.
Comput Biol Med ; 95: 167-174, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29501735

RESUMO

In lumbar interbody fusion, a porous additive manufactured (AM) cage can provide more desirable stiffness, and may be beneficial to bone ingrowth. The biomechanical influence of porous cages on stability, subsidence, and facet contact force has not been fully described. The aim of this study was to verify biomechanical effects of porous cages. A surgical finite element (FE) model of transforaminal lumbar interbody fusion (TLIF) was constructed. Partially porous (PP) cages and fully porous (FP) cages were applied. Mechanical tests were performed to obtain the mechanical parameters of porous materials. The porous cages were compared to solid titanium (TI) cage and solid PEEK cage. Four motion modes were simulated. Range of motion (ROM), cage stress, endplate stress, and facet joint force (FJF) were compared. After interbody fusion, ROM decreased by more than 90% in flexion, bending and rotation. Compared with TI and PP cages, PEEK and FP cages substantially reduced the maximum stresses in cage and endplate in all motion modes. Compared with PEEK cages, the stresses in cage and endplate for FP cages decreased, whereas the ROM increased. Compared among three FP cages, the stresses in cage and endplate decreased with increasing porosity, whereas ROM increased with increasing porosity. FJF for various cages was substantially reduced compared to the intact model in all motion modes except for flexion. In summary, fully porous cages with a porosity of between 65% and 80% may offer an alternative to solid PEEK cages in TLIF.


Assuntos
Análise de Elementos Finitos , Vértebras Lombares , Modelos Biológicos , Fusão Vertebral , Adulto , Feminino , Humanos , Porosidade
17.
Comput Methods Biomech Biomed Engin ; 21(3): 247-254, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29513028

RESUMO

Inappropriate lordotic angle of lumbar fusion cage could be associated with cage damage or subsidence. The biomechanical influence of cage lordotic angle on lumbar spine has not been fully investigated. Four surgical finite element models were constructed by inserting cages with various lordotic angles at L3-L4 disc space. The four motion modes were simulated. The range of motion (ROM) decreased with increased lordotic angle of cage in flexion, extension, and rotation, whereas it was not substantially changed in bending. The maximum stress in cage decreased with increased lordotic angle of cage in all motion modes. The maximum stress in endplate at surgical level increased with increased lordotic angle of cage in flexion and rotation, whereas it was not substantially changed in extension and bending. The facet joint force (FJF) was much smaller than that for the intact conditions in extension, bending, and rotation, while it was not substantially changed in flexion. In conclusion, the ROM, stresses in the cage and endplate at surgical level are sensitive to the lordotic angle of cage. The increased cage lordotic angle may provide better stability and reduce the risk of cage damage, whereas it may increase the risk of subsidence in flexion and rotation.


Assuntos
Análise de Elementos Finitos , Lordose/fisiopatologia , Lordose/cirurgia , Vértebras Lombares/fisiopatologia , Vértebras Lombares/cirurgia , Fusão Vertebral , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Disco Intervertebral/patologia , Disco Intervertebral/fisiopatologia , Modelos Anatômicos , Pressão , Amplitude de Movimento Articular , Reprodutibilidade dos Testes , Rotação , Estresse Mecânico
18.
World Neurosurg ; 111: e581-e591, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29288855

RESUMO

BACKGROUND: A porous additive manufactured (AM) cage may provide stability similar to that of traditional solid cages and may be beneficial to bone ingrowth. The biomechanical influence of various porous cages on stability, subsidence, stresses in cage, and facet contact force has not been fully described. The purpose of this study was to verify biomechanical effects of porous AM cages. METHODS: The surgical finite element models with various cages were constructed. The partially porous titanium (PPT) cages and fully porous titanium (FPT) cages were applied. The mechanical parameters of porous materials were obtained by mechanical test. Then the porous AM cages were compared with solid titanium (TI) cage and solid polyetheretherketone (PEEK) cage. The 4 motion modes were simulated. Range of motion (ROM), cage stress, end plate stress, and facet joint force (FJF) were compared. RESULTS: For all the surgical models, ROM decreased by >90%. Compared with TI and PPT cages, PEEK and FPT cages substantially reduced the maximum stresses in cage and end plate in all motion modes. Compared with PEEK cages, the stresses in cage and end plate for FPT cages decreased, whereas the ROM increased. Comparing FPT cages, the stresses in cage and end plate decreased with increasing porosity, whereas ROM increased with increasing porosity. After interbody fusion, FJF was substantially reduced in all motion modes except for flexion. CONCLUSIONS: Fully porous cages may offer an alternative to solid PEEK cages in lateral lumbar interbody fusion. However, it may be prudent to further increase the porosity of the cage.


Assuntos
Fenômenos Biomecânicos , Fixadores Internos , Vértebras Lombares/cirurgia , Fusão Vertebral/instrumentação , Adulto , Materiais Biocompatíveis , Feminino , Análise de Elementos Finitos , Humanos , Cetonas/química , Modelos Anatômicos , Polietilenoglicóis/química , Porosidade , Amplitude de Movimento Articular , Estresse Mecânico , Titânio , Articulação Zigapofisária/fisiopatologia
19.
Spine (Phila Pa 1976) ; 43(6): 379-387, 2018 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-28678112

RESUMO

STUDY DESIGN: Biomechanical analysis using a validated nonlinear finite element (FE) model. OBJECTIVE: The aim of this study was to combine the strategy of two-level hybrid surgery (HS) to explore how prostheses affect cervical biomechanics. SUMMARY OF BACKGROUND DATA: Few FE studies have explored differences in biomechanical behavior between combined and stand-alone structured prostheses with HS. No FE studies have considered whether the prosthesis type and hybrid strategy influence two-level HS. METHODS: Three prostheses-Prodisc-C, PCM, and DCI-were analyzed in flexion and extension during HS at C4-C6. There were two HS constructs: anterior cervical discectomy and fusion (ACDF) conducted at the C4-C5 levels and anterior cervical disc replacement (ACDR) conducted at C5-C6 levels (ACDF/ACDR); ACDR/ACDF. RESULTS: Flexion motion at adjacent levels was greater than that of intact spine. A maximum increase of 80% was observed with PCM in the ACDF/ACDR group. Extension motion at adjacent levels for both hybrid strategies with PCM, however, was similar to that of intact spine (<10% change), whereas it increased by 14% to 32% with DCI. The strain energy-storing capability with DCI tended to be similar to that of normal discs. Facet stress at the infra-adjacent level, however, significantly increased with DCI in both groups, whereas it increased with PCM and Prodisc-C only in the ACDR/ACDF group. All prostheses produced overloads on cartilage at the arthroplasty level. Prodisc-C and PCM cores showed stress above the yield stress of ultrahigh-molecular-weight polyethylene. CONCLUSION: Each prosthesis had advantages and disadvantages. In extension, DCI (vs. Prodisc-C and PCM) exhibited more compensation at adjacent levels in terms of motion, moments, and facet stress. The biomechanical performance of Prodisc-C was easily affected by the hybrid strategy. Thus, if only a combined-structure prosthesis is available for two-level HS (C4-C6 level), the hybrid strategy should be carefully evaluated and the ACDF/ACDR construct is recommended to avoid accelerating degeneration of adjacent segments. LEVEL OF EVIDENCE: 5.


Assuntos
Fenômenos Biomecânicos/fisiologia , Vértebras Cervicais/cirurgia , Degeneração do Disco Intervertebral/cirurgia , Implantação de Prótese , Humanos , Próteses e Implantes , Implantação de Prótese/métodos , Amplitude de Movimento Articular/fisiologia , Fusão Vertebral/métodos
20.
Polymers (Basel) ; 10(2)2018 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-30966178

RESUMO

This study was to investigate the nanomechanical and nanotribological properties of polyether ether ketone (PEEK)-based composites for biomedical applications and to gain a fundamental understanding of the effects of carbon fibers in carbon-fiber-reinforced PEEK (CFRPEEK) on the mechanical properties and wear performance in a microscale. Nanoindentation tests with a Berkovich indenter and nanoscratch experiments with a diamond stylus were performed on PEEK and CFRPEEK samples. The nanowear features and mechanisms of the tested samples were analyzed using 3D white-light interfering profilometry and scanning electron microscopy (SEM). The obtained results indicated that the reinforced carbon fibers increased the nanohardness and elastic modulus and decreased the friction coefficient and wear rate of PEEK. Different to many existing studies where a constant load was used in a nanoscratch test and the normal load was a key factor influencing the scratch performances of the tested specimens, stick⁻slip phenomena were observed on both PEEK and CFRPEEK in the nanoscratch tests with load increasing progressively. In constant load conditions, it was found that the major nanowear mechanisms of PEEK are adhesion, abrasion, and plastic deformation, while the nanowear mechanisms of CFRPEEK are dominated by severe adhesive wear, abrasive wear and mild fatigue. CFRPEEK has demonstrated superior nanomechanical and nanotribological performances, and hence can be considered a potential candidate for biomedical applications.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...