No correlation between radiological and clinical outcome 1 year following cervical arthrodesis.

AIM: To correlate clinical and radiological outcome following one- and two-level anterior cervical discectomy and fusion (ACDF) with stand-alone polyetheretherketone (PEEK) cages filled with demineralized bone matrix (DBM). METHODS: We performed a retrospective review of a consecutive patient cohort with degenerative disc disease that underwent ACDF with stand-alone PEEK cages filled with demineralized bone matrix (DBM) between 2010 and 2013 with a minimum follow-up of 12 months. Changes in the operated segments were measured and compared to radiographs directly after surgery. Clinical outcome was evaluated by a physical examination, pain by visual analog scale (VAS) for arm and neck. Health-related quality of life was measured using the EuroQOL questionnaire (EQ-5D). RESULTS: Of 282 consecutive cases, follow-up data were obtained from 194 (69%) cases. The median age at presentation was 54 years and 91 patients were male (46%). Ninety-eight and 96 patients had one- and two-level surgeries, respectively. Mean VAS pain was reduced from 5.2 ± 3.6 to 2.6 ± 2.4 (p < 0.001) and from 5.8 ± 3.3 to 2.1 ± 2.7 (p < 0.001) in the myelopathy and radiculopathy group, respectively. Fusion was achieved in 79 and 82% of segments in one- and two-level surgeries, respectively. Cervical alignment was better in 10 and 1%, similar in 68 and 76%, worse in 23 and 23% in one- and two-level surgeries, respectively. Subsidence was observed in 44 and 34% of segments in one- and two-level surgeries, respectively. Follow-up operations due to symptomatic adjacent disc disease or implant failure were needed in 13 (7%) and 15 (8%) of cases, respectively. Subsidence, adjacent disc disease, and cervical alignment all had no influence on the clinical outcome. CONCLUSIONS: The clinical outcome after ACDF with PEEK cages filled with demineralized bone matrix is highly satisfactory. Radiological signs of non-fusion, subsidence, and cervical alignment have no influence on clinical outcome.

Safety and efficacy of polyetheretherketone (PEEK) cages in combination with posterior pedicel screw fixation in pyogenic spinal infection.

BACKGROUND: To date, there is growing consensus that PEEK material may be used for interbody fusion in spinal infections. Data supporting that claim are however restricted to a few very small clinical series. The aim of this study is to evaluate the outcome of surgical treatment of pyogenic spinal infections with PEEK cages in combination with posterior pedicel screw fixation. METHODS: Between 2006 and 2013, a total of 211 patients suffering from spondylodiscitis underwent surgical debridement and instrumentation. There were 52 cases where PEEK cages were used. Laboratory and physical examinations were assessed at a 3-month follow-up. Last follow-up was performed with at a minimum of 12 months after surgery via a telephone interview. RESULTS: Mean age at presentation was 67 years, with 19 (37 %) male patients and 33 (63 %) female. Distribution of the infection was lumbar in 29 (56 %%), thoracic in 3 (6 %) and cervical in 11 (21 %) cases. Nine patients (17 %) had concomitant non-contiguous spondylodiscitis. Epidural abscess was found in 17 patients (33 %); 48 (92 %%) had pain; neurological deficits were found in 20 patients (38 %). All patients in this series underwent surgical debridement with instrumentation of the spine. Postoperative intravenous antibiotics were administered for 15.4 ± 6.8 days followed by 2.9 ± 0.5 months of oral antibiotics. Complete resolution of the infection was achieved in all cases. Of the 28 patients with neurological deficits, 6 had full recovery and 10 had improved incompletely after surgery. One patient suffered from a pulmonary embolism postoperatively. There were no mortalities. CONCLUSIONS: Use of PEEK cages for interbody fusion is feasible and safe in patients suffering from a pyogenic spinal infection.

A method for segmentation of dental implants and crestal bone.

PURPOSE: Medical imaging and in particular digital radiographic images offer a great deal of information to dentists in the clinical diagnosis and treatment processes on a daily basis. This paper presents a new method aimed to produce an accurate segmentation of dental implants and the crestal bone line in radiographic images. With this, it is possible computing several measures to biomechanical and clinical evaluation of dental implants positioning and evolution. METHODS: The proposed segmentation method includes two major steps: (1) the preprocessing that combine denoising filters, morphological operations and histogram threshold techniques and (2) the final segmentation involving made-to-measure adjusted and trained active shape models for detecting the precise location of the intended structures. RESULTS: Resulting measurements were compared to manual measurements made by experts on representative radiographs from patients. The calculated intraclass correlation coefficient was 0.75 and showed good reliability of the method, and the Bland-Altman analysis showed 95% of the values within the limits of agreement. The mean of the differences between the manual and method-driven measurements was 0.049 mm ([Formula: see text]) 95% CI, inferior to the established limit (0.15mm). CONCLUSIONS: It was demonstrated that the method achieved a precise segmentation of the intended structures. The validation process on standardized periapical radiographs showed good agreement between the manual measurements and the ones produced by the new method. Future work will be focused on making the method more robust to densitometry changes and to validate the method on non-standardized radiographs.

A 3D optical metamaterial made by self-assembly.

Optical metamaterials have unusual optical characteristics that arise from their periodic nanostructure. Their manufacture requires the assembly of 3D architectures with structure control on the 10-nm length scale. Such a 3D optical metamaterial, based on the replication of a self-assembled block copolymer into gold, is demonstrated. The resulting gold replica has a feature size that is two orders of magnitude smaller than the wavelength of visible light. Its optical signature reveals an archetypal Pendry wire metamaterial with linear and circular dichroism.

Mimicking the colourful wing scale structure of the Papilio blumei butterfly.

The brightest and most vivid colours in nature arise from the interaction of light with surfaces that exhibit periodic structure on the micro- and nanoscale. In the wings of butterflies, for example, a combination of multilayer interference, optical gratings, photonic crystals and other optical structures gives rise to complex colour mixing. Although the physics of structural colours is well understood, it remains a challenge to create artificial replicas of natural photonic structures. Here we use a combination of layer deposition techniques, including colloidal self-assembly, sputtering and atomic layer deposition, to fabricate photonic structures that mimic the colour mixing effect found on the wings of the Indonesian butterfly Papilio blumei. We also show that a conceptual variation to the natural structure leads to enhanced optical properties. Our approach offers improved efficiency, versatility and scalability compared with previous approaches.

Aplicação de metodologias de segmentação de imagem para medição automatizada dos níveis ósseos de implantes em radiografias periapicais padronizadas / Application of image segmentation methods for automated implant bone level measurements in periapical standardized radiographs

Objetivo: validar um método automatizado para a determinação de níveis ósseos de implantes. Material e métodos: dois examinadores analisaram 60 radiografias de implantes (Camlog Screw-Line) através de uma interface gráfica desenvolvida para a aplicação do método de segmentação de imagem. O processo baseou-se na aplicação de uma série de passos automatizados para isolar a crista óssea e os implantes, a fim de computar a intersecção entre o osso e o implante. Os níveis ósseos foram posteriormente computados através da determinação da distância entre o primeiro contato osso-implante e o ombro do implante. A concordância e a exatidão do método foram determinadas por comparação dos níveis ósseos obtidos pelo método com os correspondentes obtidos manualmente. Resultados: não foram determinadas diferenças entre os resultados das medições manuais e as obtidas através do método de segmentação (teste Anova para medidas repetidas, p=0,852). A análise de concordância revelou um coeficiente de correlação intraclasse de 0,839 ([0,783-0,884, 95% IC], p < 0,01). Mais de 60% das medições foram consideradas exatas. Conclusões: o método proposto provou ser uma ferramenta precisa e fidedigna para a medição de níveis ósseos, contribuindo para a diminuição da variabilidade entre observadores.