Comparison of silicate-substituted calcium phosphate (Actifuse®) with rhBMP-2 (Infuse®) in posterolateral instrumented lumbar fusion

Study Design This was a randomised controlled trial in patients with degenerative disc disease (DDD) who underwent instrumented posterolateral lumbar fusion (PLF) surgery. Objective The aim of this study was to assess the efficacy of the bone grafting substitute, silicate-substituted calcium phosphate (SiCaP) compared with bone morphogenetic protein (rhBMP-2) and to evaluate clinical outcomes over a period of two years. Methods Patients undergoing PLF surgery for DDD at a single centre were recruited and randomised to one of two groups; SiCaP (n=9) or rhBMP-2 (n=10). One patient withdrew prior to randomisation and another from the rhBMP-2 group after randomisation. The radiological and clinical outcomes were examined and compared. Fusion was assessed at 12 months with computed tomography (CT) and plain radiographs. Clinical outcomes were evaluated by recording measures of pain, quality of life, disability and neurological status from six weeks to two years postoperatively. Results In the SiCaP and rhBMP-2 groups, fusion was observed in 9/9 and 8/9 patients respectively. Pain and disability scores were reduced and quality of life increased in both groups. Leg pain, disability and satisfaction scores were similar between the groups at each postoperative time point, however, back pain was less at six weeks and quality of life was higher at six months in the SiCaP group than the rhBMP-2 group. Conclusions SiCaP and rhBMP-2 were comparable in terms of achieving successful bone growth and fusion. Both groups similarly alleviated pain and improved quality of life, neurological, satisfaction and return to work outcomes following PLF surgery.

Efficacy and safety of adalimumab in patients with non-radiographic axial spondyloarthritis: Results of a randomised placebo-controlled trial (ABILITY-1)

Purpose: To evaluate the efficacy and safety of adalimumab in patients with non-radiographic axial spondyloarthritis (nr-axSpA). Methods: Patients fulfilled Assessment of Spondyloarthritis international Society (ASAS) criteria for axial spondyloarthritis, had a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score of ≥ 4, total back pain score of ≥ 4 (10 cm visual analogue scale) and inadequate response, intolerance or contraindication to non-steroidal anti-inflammatory drugs (NSAIDs); patients fulfilling modified New York criteria for ankylosing spondylitis were excluded. Patients were randomised to adalimumab (N=91) or placebo (N=94). The primary endpoint was the percentage of patients achieving ASAS40 at week 12. Efficacy assessments included BASDAI and Ankylosing Spondylitis Disease Activity Score (ASDAS). MRI was performed at baseline and week 12 and scored using the Spondyloarthritis Research Consortium of Canada (SPARCC) index. Results: Significantly more patients in the adalimumab group achieved ASAS40 at week 12 compared with patients in the placebo group (36% vs 15%, p<0.001). Significant clinical improvements based on other ASAS responses, ASDAS and BASDAI were also detected at week 12 with adalimumab treatment, as were improvements in quality of life measures. Inflammation in the spine and sacroiliac joints on MRI significantly decreased after 12 weeks of adalimumab treatment. Shorter disease duration, younger age, elevated baseline C-reactive protein or higher SPARCC MRI sacroiliac joint scores were associated with better week 12 responses to adalimumab. The safety profile was consistent with what is known for adalimumab in ankylosing spondylitis and other diseases. Conclusions: In patients with nr-axSpA, adalimumab treatment resulted in effective control of disease activity, decreased inflammation and improved quality of life compared with placebo. Results from ABILITY-1 suggest that adalimumab has a positive benefit-risk profile in active nr-axSpA patients with inadequate response to NSAIDs.

Spinal inflammation in the absence of sacroiliac joint inflammation on magnetic resonance imaging in patients with active nonradiographic axial spondyloarthritis

Objective: To evaluate the presence of spinal inflammation with and without sacroiliac (SI) joint inflammation on magnetic resonance imaging (MRI) in patients with active nonradiographic axial spondyloarthritis (SpA), and to compare the disease characteristics of these subgroups. Methods: ABILITY-1 is a multicenter, randomized, controlled trial of adalimumab versus placebo in patients with nonradiographic axial SpA classified using the Assessment of SpondyloArthritis international Society axial SpA criteria. Baseline MRIs were centrally scored independently by 2 readers using the Spondyloarthritis Research Consortium of Canada (SPARCC) method for the SI joints and the SPARCC 6-discovertebral unit method for the spine. Positive evidence of inflammation on MRI was defined as a SPARCC score of >2 for either the SI joints or the spine. Results: Among patients with baseline SPARCC scores, 40% had an SI joint score of >2 and 52% had a spine score of >2. Forty-nine percent of patients with baseline SI joint scores of <2, and 58% of those with baseline SI joint scores of >2, had a spine score of >2. Comparison of baseline disease characteristics by baseline SI joint and spine scores showed that a greater proportion of patients in the subgroup with a baseline SPARCC score of >2 for both SI joints and spine were male, and patients with spine and SI joint scores of <2 were younger and had shorter symptom duration. SPARCC spine scores correlated with baseline symptom duration, and SI joint scores correlated negatively with the baseline Bath Ankylosing Spondylitis Disease Activity Index, but neither correlated with the baseline Ankylosing Spondylitis Disease Activity Score, total back pain, the patient's global assessment of disease activity, the Bath Ankylosing Spondylitis Functional Index, morning stiffness, nocturnal pain, or C-reactive protein level. Conclusion: Assessment by experienced readers showed that spinal inflammation on MRI might be observed in half of patients with nonradiographic axial SpA without SI joint inflammation.

Analytical And Experimental Aeroacoustic Studies Of Open-Ended 3-Duct Perforated Elements Used In Mufflers

Perforated element mufflers have been known to have good acousticp erformancew, henu sedo n automotive xhausst ystemsIn. thel astd ecadea nda half, plugm ufflersc, oncentrihc oler esonators, and three-ductc losed-endp erforatede lementsh ave been studied.T he presenti nvestigation concernso pen-endedt,h ree-ducpt erforatede lementsw, hich are knownt o combineh igh acoustic transmissiolno ss with low back pressuresT. he governinge quationsh ave been solved in the frequencyd omain,u singt he recouplinga pproacha longw ith appropriatbe oundaryc onditionst,o derivet he transferm atrixa ndt hent o calculaten oiser eductiona ndt ransmissiolno ss.T he predicted noiser eductionv aluesh aveb eens hownt o corroboratew ell with experimentallyo bservedv alues. Finally,p arametrics tudiesh aveb eend onet o draw designc urvesf or suchm ufflers.

Broadband Suspended Microstrip Antenna For Circular Polarization

In this paper we propose a circularly polarized (CP) microstrip antenna on a suspended substrate with a coplanar capacitive feed and a slot within the rectangular patch. The antenna has an axial ratio bandwidth (< 3 dB) of 7.1%. The proposed antenna exhibits a much higher impedance bandwidth of about 49% (S11 < -10 dB) and also yields return loss better than -15 dB in the useful range of circular polarization. Measured characteristics of the antenna are in good agreement with the simulated results. The radiation patterns indicate good cross polarization rejection and low back lobe radiations. The design proposed here can be scaled to any frequency of interest.

Inter-lamellar shear resistance confers compressive stiffness in the intervertebral disc: An image-based modelling study on the bovine caudal disc

The intervertebral disc withstands large compressive loads (up to nine times bodyweight in humans) while providing flexibility to the spinal column. At a microstructural level, the outer sheath of the disc (the annulus fibrosus) comprises 12–20 annular layers of alternately crisscrossed collagen fibres embedded in a soft ground matrix. The centre of the disc (the nucleus pulposus) consists of a hydrated gel rich in proteoglycans. The disc is the largest avascular structure in the body and is of much interest biomechanically due to the high societal burden of disc degeneration and back pain. Although the disc has been well characterized at the whole joint scale, it is not clear how the disc tissue microstructure confers its overall mechanical properties. In particular, there have been conflicting reports regarding the level of attachment between adjacent lamellae in the annulus, and the importance of these interfaces to the overall integrity of the disc is unknown. We used a polarized light micrograph of the bovine tail disc in transverse cross-section to develop an image-based finite element model incorporating sliding and separation between layers of the annulus, and subjected the model to axial compressive loading. Validation experiments were also performed on four bovine caudal discs. Interlamellar shear resistance had a strong effect on disc compressive stiffness, with a 40% drop in stiffness when the interface shear resistance was changed from fully bonded to freely sliding. By contrast, interlamellar cohesion had no appreciable effect on overall disc mechanics. We conclude that shear resistance between lamellae confers disc mechanical resistance to compression, and degradation of the interlamellar interface structure may be a precursor to macroscopic disc degeneration.

Does the addition of Clonidine to lumbar nerve root blocks improve outcome? A randomised, prospective, single-blinded controlled pilot study

Purpose To evaluate if adding clonidine to a standard nerve root block containing local anaesthetic and steroid improved the outcome of patients with severe lumbar nerve root pain secondary to MRI proven lumbar disc prolapse. Methods We undertook a single blind, prospective, randomised controlled trial evaluating 100 consecutive patients with nerve root pain secondary to lumbar disc prolapse undergoing trans-foraminal epidural steroid injection either with or without the addition of clonidine. 50 patients were allocated to each arm of the study. The primary outcome measure was the avoidance of a second procedure- repeat injection or micro-discectomy surgery. Secondary outcome measures were also studied: pain scores for leg and back pain using a visual analogue scale (VAS), the Roland Morris Disability Questionnaire (RMDQ) and the Measure Your Own Medical Outcome Profile (MYMOP). Follow up was carried out at 6 weeks, 6 months and 1 year. Results No serious complications occurred. Of the 50 patients who received the addition of clonidine, 56% were classified as successful injections, with no further intervention required, as opposed to 40% who received the standard injection. This difference did not reach statistical significance (p=0.109, chi-squared test). All secondary measures showed no statistically significant differences between the groups except curiously, the standard group who had been classified as successful had better leg pain relief than the clonidine group (p=0.026) at 1 year. Conclusions This pilot study has shown a 16% treatment effect with adding clonidine to lumbar nerve root blocks and that it is a safe injectate for this purpose.

Irritable bowel syndrome in the general population : epidemiology, comorbidity and societal costs

Background: Irritable bowel syndrome (IBS) is a common functional gastrointestinal (GI) disorder characterised by abdominal pain and abnormal bowel function. It is associated with a high rate of healthcare consumption and significant health care costs. The prevalence and economic burden of IBS in Finland has not been studied before. The aims of this study were to assess the prevalence of IBS according to various diagnostic criteria and to study the rates of psychiatric and somatic comorbidity in IBS. In addition, health care consumption and societal costs of IBS were to be evaluated. Methods: The study was a two-phase postal survey. Questionnaire I identifying IBS by Manning 2 (at least two of the six Manning symptoms), Manning 3 (at least three Manning symptoms), Rome I, and Rome II criteria, was mailed to a random sample of 5 000 working age subjects. It also covered extra-GI symptoms such as headache, back pain, and depression. Questionnaire II, covering rates of physician visits, and use of GI medication, was sent to subjects fulfilling Manning 2 or Rome II IBS criteria in Questionnaire I. Results: The response rate was 73% and 86% for questionnaires I and II. The prevalence of IBS was 15.9%, 9.6%, 5.6%, and 5.1% according to Manning 2, Manning 3, Rome I, and Rome II criteria. Of those meeting Rome II criteria, 97% also met Manning 2 criteria. Presence of severe abdominal pain was more often reported by subjects meeting either of the Rome criteria than those meeting either of the Manning criteria. Presence of depression, anxiety, and several somatic symptoms was more common among subjects meeting any IBS criterion than by controls. Of subjects with depressive symptoms, 11.6% met Rome II IBS criteria compared to 3.7% of those with no depressiveness. Subjects meeting any IBS criteria made more physician visits than controls. Intensity of GI symptoms and presence of dyspeptic symptoms were the strongest predictors of GI consultations. Presence of dyspeptic symptoms and a history of abdominal pain in childhood also predicted non-GI visits. Annual GI related individual costs were higher in the Rome II group (497 ) than in the Manning 2 group (295 ). Direct expenses of GI symptoms and non GI physician visits ranged between 98M for Rome II and 230M for Manning 2 criteria. Conclusions: The prevalence of IBS varies substantially depending on the criteria applied. Rome II criteria are more restrictive than Manning 2, and they identify an IBS population with more severe GI symptoms, more frequent health care use, and higher individual health care costs. Subjects with IBS demonstrate high rates of psychiatric and somatic comorbidity regardless of health care seeking status. Perceived symptom severity rather than psychiatric comorbidity predicts health care seeking for GI symptoms. IBS incurs considerable medical costs. The direct GI and non-GI costs are equivalent to up to 5% of outpatient health care and medicine costs in Finland. A more integral approach to IBS by physicians, accounting also for comorbid conditions, may produce a more favourable course in IBS patients and reduce health care expenditures.

Condições de trabalho de ambiente cirúrgico e a saúde dos trabalhadores de enfermagem

O Centro Cirúrgico é um serviço especializado com estrutura física e organizacional complexa, normas e rotinas rigorosas, intensa atividade técnica, aparato tecnológico que requer profissionais treinados. A pesquisa teve como objeto de estudo os fatores de riscos ocupacionais e os problemas de saúde decorrentes do trabalho, identificados pelos profissionais de enfermagem de um Centro Cirúrgico de um Hospital Universitário da cidade do Rio de Janeiro. Os objetivos foram: analisar os fatores de riscos ocupacionais que possibilitam o aparecimento de problemas de saúde nos profissionais de enfermagem do Centro Cirúrgico segundo esses trabalhadores; descrever as características sociodemográficas dos profissionais lotados no Centro Cirúrgico; levantar os fatores de risco do ambiente cirúrgico identificados pelos trabalhadores de enfermagem do Centro Cirúrgico de um Hospital Universitário; e, discutir a relação entre os riscos do ambiente de trabalho e os problemas de saúde autoreferidos por trabalhadores de enfermagem do Centro Cirúrgico. A metodologia usada foi uma pesquisa não-experimental, de natureza descritiva, com abordagem quantitativa, desenvolvida em um centro cirúrgico de um hospital universitário federal da cidade do Rio de Janeiro. A população escolhida foi composta de trabalhadores da equipe de enfermagem, lotados no mínimo há seis meses neste serviço e que aceitassem participar da pesquisa. O questionário de coleta de dados utilizado foi adaptado por Mauro dos Guias e Avaliação de riscos em indústrias de Boix e Vogel. O estudo foi submetido e aprovado pelo Comitê de Ética em Pesquisa (CEP) do Hospital Universitário em estudo, através Parecer Consubstanciado no. 287/10, protocolo no. 217/09. Os dados foram analisados através do Programa Statistical Package for the Social Sciences (SPSS), versão 13.0. Os riscos biológicos foram os mais apontados pelos trabalhadores de enfermagem, seguidos dos riscos químicos, ergonômicos e de acidentes ou mecânicos. As doenças provocadas pelo trabalho mais referidas foram o estresse, a lombalgia, as varizes, a fadiga muscular e os problemas de articulação. As doenças agravadas pelo trabalho mais citadas foram as varizes, a lombalgia, os problemas de articulação, o estresse, as lesões de coluna vertebral, os problemas digestivos e os transtornos do sono. Conclui-se que o Serviço estudado possui riscos inerentes às atividades desenvolvidas que caracterizam os problemas relacionados pelos trabalhadores, e que são passíveis de controle através da intensificação de um Programa de Prevenção de Riscos Ambientais voltado para o Centro Cirúrgico. A partir da NR 17 e a 32, pode-se consultar as diretrizes para prevenção dos riscos encontrados. Uma estratégia de reposição digna de pessoal de enfermagem é imprescindível, assim como estudo e implantação de um Programa de Prevenção de Riscos laborais aos trabalhadores do Centro Cirúrgico, e utilização do questionário aos demais membros da equipe multiprofissional.

Condições de trabalho e problemas de saúde em Enfermagem na maternidade de um hospital universitário

Trata-se de um estudo fundamentado na Epidemiologia, do tipo quantitativo, não-experimental, transversal apoiado na estatística descritiva e inferencial, baseado no seguinte problema de estudo: qual a associação entre problemas de saúde e riscos ocupacionais a partir da percepção dos trabalhadores de enfermagem da maternidade de um hospital universitário? Teve como objetivo estudar os problemas de saúde dos trabalhadores de enfermagem e sua associação com o trabalho, a partir de suas percepções. Foi desenvolvido em uma maternidade de um hospital universitário do estado do Rio de Janeiro, com uma amostra constituída por 60 trabalhadores de enfermagem, em 2009. Utilizou-se para coleta de dados um questionário de Boix e Vogel (1997) adaptado por Mauro (2009). Os dados foram analisados através do Programa Statistical Package for the Social Sciences (SPSS) versão 12.0. Todos os tipos de risco foram discretamente apontados pelos participantes como existentes no campo de estudo com destaque para os riscos de acidente e mecânicos, riscos ergonômicos e as situações de conflito e violência. Os resultados configuram um ambiente de trabalhado que necessita de adequações de naturezas diversas, para evitar conseqüências negativas na saúde dos trabalhadores, visando a minimização, controle ou eliminação dos referidos riscos. Em relação aos problemas de saúde evidenciados, os que se destacaram foram a depressão, o estresse, os problemas oculares, a hipertensão, as varizes, os problemas respiratórios e as lombalgias. Recomenda-se à instituição promover a melhoria das condições de trabalho, maior atenção à saúde dos trabalhadores e a efetivação de programas de promoção da saúde.

Visão dos trabalhadores acerca das suas condições de trabalho em um centro integrado de saúde

Pesquisa realizada em um Centro Integrado de Saúde inserido no âmbito de uma Instituição de Ensino Superior Particular, situada no Município do Rio de Janeiro. Metodologia fundamentada em uma abordagem quantitativa, não-experimental, apoiada na estatística inferencial descritiva, baseada no problema de estudo: Quais os fatores que caracterizam as condições de trabalho em um Centro Integrado de Saúde (CIS)? Teve como objetivo, analisar a visão dos trabalhadores em um Centro Integrado de Saúde acerca de suas condições de trabalho. Utilizou-se uma população constituída de 73 trabalhadores. Foram aplicados dois instrumentos: o caderno B, que consta de um questionário auto-aplicativo sobre Riscos e Danos e o caderno C que é um formulário de observação sobre as condições de trabalho de Mauro & Mauro (2009) adaptado de Boix e Vogel (1997). Os dados foram analisados através do Programa Statistical Package for the Social Sciences (SPSS) versão 13.0. Na visão dos trabalhadores, os resultados em relação aos riscos (físico, químico, biológico, ergonômico e de acidente) e considerando as variáveis desconhece, não acontece, raramente e freqüentemente, os mesmos indicaram uma freqüência diversificada, embora a maior incidência esteja no grupo de risco biológico com a variável freqüentemente e nos demais a variável raramente. Quanto aos problemas de saúde evidenciados, no questionário B em ordem decrescente, os que se destacaram foram os problemas oculares; lesão por acidente; varizes; dor de cabeça; hipertensão; doenças infecciosas; lombalgias; lesão da coluna vertebral; dores musculares crônicas; problemas de articulação e estresse. Quanto aos resultados do Caderno C, através de observação pelos especialistas, os riscos são variáveis, destacando-se os riscos ergonômicos, os de acidentes e os biológicos. Conclui-se que as condições de trabalho não são satisfatórias evidenciando-se a falta de conhecimento sobre o conteúdo da investigação, assinalados as respostas na alternativa (desconhece) e da aplicação correta das medidas de prevenção de riscos ocupacionais. Recomenda-se neste sentido uma incorporação institucional dos trabalhadores valorizando a capacitação desses profissionais de saúde, com ênfase na promoção da saúde, segurança, meio ambiente de trabalho e os conhecimentos de ergonomia. Como também uma atuação integrada do Serviço Especializado em Engenharia e em Medicina do Trabalho (SESMT) com a Comissão de Biossegurança, além do incentivo à gestão participativa, educação continuada efetiva, e a criação do Comitê de Ergonomia, para a análise e intervenção das propostas.

Jarduera Fisikoaren eta Kirolaren Zientzien ikasleen postura eta bizkarreko mina.

[EUS] Lan honen helburua egoera posturala eta bizkarreko minaren pertzepzioaren azterketa sakonagoa egitea da. Bizkarreko min zein desoreka posturalek gaur egun duten nagusitasuna ikusita, egoera azaleratu eta honen kausak zeintzuk diren ezagutu nahi dira. Honetarako UPV-EHUko Jarduera Fisikoaren eta Kirolaren Zientzien Fakultateko ikasleen (n=25) postura-aldaketak zein bizkarreko minaren magnitudea eta pertzepzioa nolakoak diren aztertuko ditugu. Egindako analisia longitudinala izan da. Ikasketetan sartu zirenean lehenengo neurketa egin zitzaien eta ikasketen azkeneko urtean azken neurketa. QPS-200 Shekel Posture Analyzer erremintari esker pisuaren banaketaren datu numerikoak lortu ditugu. Bizkarreko mina eta pertzepzioari dagozkienez, NASS osasun galdetegia erabili izan da. Posturaren neurketek erakutsi dutenez, bariazio handiena pertsonen artekoa da. Hetereogeneotasun handiena aurre-atze banaketak azaleratu duelarik, gehienbat lehenengo neurketan (2012: DS=9,33 begiak zabalik eta DS=9,99 begiak itxita; 2014: DS=7,37 begiak zabalik eta DS=7,94 begiak itxita). Aurkitu den efektu signifikatibo bakarra (p<0.05), bestalde, neurketa data da. Bizkarreko minaren pertzepzioak gora egin du urteak aurrera joan ahala (subjektuen %64 2012an; subjektuen %72 2014an) baina egunerokotasunean minak sortzen dituen zailtasunak behera egin du (%28 2012an; %20 2014an).

Invalidez por dor nas costas entre os contribuintes da Previdência Social, Brasil, 2007

O presente estudo teve por objetivo analisar a magnitude e a distribuição das aposentadorias por invalidez por dor nas costas no Brasil em 2007. Trata-se de estudo descritivo utilizando registros do Sistema Único de Informações de Benefícios e dos Anuários Estatísticos da Previdência Social de 2007. Foram concedidos 10.839 benefícios de aposentadoria por invalidez referentes a dor nas costas. As variáveis idade, sexo, estados e grandes regiões foram utilizadas para o cálculo das taxas de incidência de dor nas costas em aposentadorias por invalidez enquanto as variáveis faixa salarial, ramo de atividade, clientela e tipo de filiação, foram utilizadas para o cálculo das proporções. Para o cálculo das dez primeiras causas de aposentadoria por invalidez foram utilizados os dados de todas as causas deste benefício. Foram analisados ainda, os dias de trabalho perdidos por invalidez por atividade profissional. A dor nas costas idiopática foi a primeira causa de invalidez em 2007. A maioria dos beneficiários residia em área urbana, era composta por comerciários e recebia até três salários mínimos. A taxa de incidência de dor nas costas em aposentadorias por invalidez foi de 29,96 por 100.000 contribuintes. Este valor foi mais elevado no sexo masculino e apresentou crescimento à medida que se eleva a faixa etária. A taxa de Rondônia, estado com a maior proporção de trabalhadores rurais foi mais de quatro vezes o esperado (RT=4,05) enquanto a segunda maior taxa foi aproximadamente duas vezes o esperado (RT=2,07). A dor nas costas foi uma importante causa de invalidez em 2007. As diferenças observadas entre as incidências por estado apontam para a necessidade de melhor compreender os fatores associados a este importante problema de morbidade para a população trabalhadora brasileira.

Composite hydrogels for nucleus pulposus tissue engineering

Tissue engineering offers a paradigm shift in the treatment of back pain. Engineered intervertebral discs could replace degenerated tissue and overcome the limitations of current treatments, which substantially alter the biomechanical properties of the spine. The centre of the disc, the nucleus pulposus, is an amorphous gel with a large bound water content and it can resist substantial compressive loads. Due to similarities in their compositions, hydrogels have frequently been considered as substitutes for the nucleus pulposus. However, there has been limited work characterising the time-dependent mechanical behaviour of hydrogel scaffolds for nucleus pulposus tissue engineering. Poroelastic behaviour, which plays a key role in nutrient transport, is of particular importance. Here, we investigate the time-dependent mechanical properties of gelatin and agar hydrogels and of gelatin-agar composites. The time-dependent properties of these hydrogels are explored using viscoelastic and poroelastic frameworks. Several gel formulations demonstrate comparable equilibrium elastic behaviour to the nucleus pulposus under unconfined compression, but permeability values that are much greater than those of the native tissue. A range of time-dependent responses are observed in the composite gels examined, presenting the opportunity for targeted design of custom hydrogels with combinations of mechanical properties optimized for tissue engineering applications. © 2011 Elsevier Ltd.

Electrospun fiber - Hydrogel composites for nucleus pulposus tissue engineering

New materials are needed to replace degenerated intervertebral disc tissue and to provide longer-term solutions for chronic back-pain. Replacement tissue potentially could be engineered by seeding cells into a scaffold that mimics the architecture of natural tissue. Many natural tissues, including the nucleus pulposus (the central region of the intervertebral disc) consist of collagen nanofibers embedded in a gel-like matrix. Recently it was shown that electrospun micro- or nano-fiber structures of considerable thickness can be produced by collecting fibers in an ethanol bath. Here, randomly aligned polycaprolactone electrospun fiber structures up to 50 mm thick are backfilled with alginate hydrogels to form novel composite materials that mimic the fiber-reinforced structure of the nucleus pulposus. The composites are characterized using both indentation and tensile testing. The composites are mechanically robust, exhibiting substantial strain-to-failure. The method presented here provides a way to create large biomimetic scaffolds that more closely mimic the composite structure of natural tissue. © 2012 Materials Research Society.