The significance of facet joint cross-sectional area on magnetic resonance imaging in relationship to cervical degenerative spondylolisthesis

Background contextCharacteristic changes of the facet joints, including synovial cysts, facet joint hypertrophy, and facet joint effusions, on magnetic resonance imaging (MRI) and computed tomography have been associated with lumbar degenerative spondylolisthesis. The cervical facets have not been examined for associations with cervical degenerative spondylolisthesis similar to those seen in the lumbar spine.PurposeTo define abnormalities of the facet joints seen on supine MRI that correlate with cervical spondylolisthesis seen on upright radiographs.Study designRetrospective radiographic review of consecutive patients with a universally applied standard.Patient sampleA total of 204 consecutive patients from a single institution, with both an MRI and upright radiographs, were reviewed.Outcome measuresSagittal plane displacement on upright lateral radiographs was compared with MRI. The total area of the facet joint and the amount of facet joint asymmetry were measured on an axial MRI.MethodsThe data were analyzed to determine a significant association between the cervical degenerative spondylolisthesis and the following: facet joint asymmetry, increased total area of the facet joint, and age.ResultsDegenerative spondylolisthesis was seen in 26 patients at C3–C4 and in 27 patients at C4–C5. Upright radiographs identified significantly more degenerative spondylolisthesis than MRIs at levels C3–C4 and C4–C5, 26 versus 6 (p<.001) at C3–C4 and 27 versus 11 (p<.001) at C4–C5. Patients with degenerative spondylolisthesis were more likely to be older, have a larger total facet area, and more facet asymmetry at C3–C4 and C4–C5 (p<.05).ConclusionsSupine MRIs underestimate sagittal displacement compared with upright lateral radiographs. Asymmetric facet hypertrophy at C3–C4 and C4–C5 is associated with degenerative spondylolisthesis on upright lateral films even in the absence of anterolisthesis on supine MRIs.     

Expression of EGFR, VEGF, and NOTCH1 Suggest Differences in Tumor Angiogenesis in HPV-Positive and HPV-Negative Head and Neck Squamous Cell Carcinoma

There is current interest in anti-angiogenesis therapies for head and neck squamous cell carcinomas (HNSCC), although the utility of these therapies in human papillomavirus (HPV) positive and HPV-negative HNSCC is unclear. Therefore, we explored heterogeneity in expression of a distal factor in angiogenesis (EGFR, the epidermal growth factor receptor), a proximal factor in angiogenesis (VEGF, the vascular endothelial growth factor) and a putative factor in angiogenesis (NOTCH1) in a HNSCC case series using immunohistochemistry in N = 67 cases (27 HPV-positive, 40 HPV-negative, by in situ hybridization). Box plots and the Wilcoxon rank sum or Kruskal–Wallis tests were used to compare staining scores (intensity × percent of cells staining) by HPV status and lifestyle factors. Associations between EGFR, VEGF, and NOTCH1 were assessed using box plots and Spearman correlation (ρ) in all cases, and stratified by HPV status. HPV-negative HNSCC over-expressed EGFR [median (range): 30 (0–300)] relative to HPV-positive HNSCC [7.5 (0–200)] (P = 0.006). VEGF and NOTCH1 were unrelated to HPV status (P > 0.05). EGFR was associated with VEGF in HPV-negative (ρ = 0.40, P = 0.01) but not HPV-positive HNSCC (ρ = 0.25, P = 0.20). NOTCH1 and VEGF were associated in HPV-negative (ρ = 0.40, P = 0.01) but not HPV-positive tumors (ρ = −0.12, P = 0.57). NOTCH1 was not associated with EGFR (P > 0.05). Our results are suggestive of heterogeneity in HNSCC angiogenesis. Future studies should explore angiogenesis mechanisms in HPV-positive and HPV-negative HNSCC.

Electronic supplementary material

The online version of this article (doi:10.1007/s12105-013-0447-y) contains supplementary material, which is available to authorized users.     

Neuroprotective Effect of Physical Exercise in a Mouse Model of Alzheimer’s Disease Induced by β-Amyloid1–40 Peptide

This study was designed to investigate the potential neuroprotective effect of exercise in a mouse model of Alzheimer’s disease (AD) induced by intracerebroventricular (i.c.v.) injection of beta-amyloid_1–40 (Aβ_1–40) peptide. For this aim, male Swiss Albino mice were submitted to swimming training (ST) with progressive increase in intensity and duration for 8 weeks before Aβ_1–40 administration (400 pmol/animal; 3 μl/site, i.c.v. route). The cognitive behavioral, oxidative stress, and neuroinflammatory markers in hippocampus and prefrontal cortex of mice were assessed 7 days after Aβ_1–40 administration. Our results demonstrated that ST was effective in preventing impairment in short- and long-term memories in the object recognition test. ST attenuated the increased levels of reactive species and decreased non-protein thiol levels in hippocampus and prefrontal cortex induced by Aβ_1–40. Also, Aβ_1–40 inhibited superoxide dismutase activity and increased glutathione peroxidase, glutathione reductase, and glutathione S-transferase activities in hippocampus and prefrontal cortex—alterations that were mitigated by ST. In addition, ST was effective against the increase of tumor necrosis factor-alpha and interleukin-1 beta levels and the decrease of interleukin-10 levels in hippocampus and prefrontal cortex. This study confirmed the hypothesis that exercise is able to protect against some mechanisms of Aβ_1–40-induced neurotoxicity. In conclusion, we suggest that exercise can prevent the cognitive decline, oxidative stress, and neuroinflammation induced by Aβ_1–40 in mice supporting the hypothesis that exercise can be used as a non-pharmacological tool to reduce the symptoms of AD.     

Magnetic resonance fingerprinting: a technical review

Multiparametric quantitative imaging is gaining increasing interest due to its widespread advantages in clinical applications. Magnetic resonance fingerprinting is a recently introduced approach of fast multiparametric quantitative imaging. In this article, magnetic resonance fingerprinting acquisition, dictionary generation, reconstruction, and validation are reviewed.     

Head‐locking durability of fixed and variable angle locking screws under repetitive loading

Polyaxial locking screws are increasingly applied in fracture fixation. To investigate the durability of the head‐locking mechanism, the removal torque of variable angle (VA) and fixed angle (FA) stainless steel and titanium locking screws was investigated without and after a cyclic loading test. Stainless steel (St) and titanium (Ti) 2.4 mm orthogonally inserted FA screws and 2.4 mm VA screws inserted in different inclinations (0°–15°) (n = 6 per group) were locked at 0.8 Nm. Removal torque was determined without (W) and after (A) cyclic loading (sinusoidal load, 5 Hz, constant amplitude of 25 N, up to 10′000 cycles, or failure). Significant differences in‐between the groups were detected by Student's t‐test (p < 0.05). Except VA Ti in 0deg and FA, all groups exhibited a drop in removal torque below the insertion torque without and after cyclic testing. The removal torque was (St: FA W:0.81 Nm ± 0.04 A:0.72Nm ± 0.04; VA0deg W:0.73 Nm ± 0.04 A:0.65 Nm ± 0.05; VA15deg W:0.51 Nm ± 0.05 A:0.50 Nm ± 0.08; Ti: FA W:0.82 Nm ± 0.03 A:0.70 Nm ± 0.04; VA0deg W:0.80 Nm ± 0.02 A:0.72 Nm ± 0.05; VA15deg W:0.55 Nm ± 0.03 A:0.54 Nm ± 0.06). In all groups, the removal torque after cyclic testing did not drop below 16% of the removal torque without cyclic testing. No head loosening was observed after cyclic testing. Stainless steel and titanium 2.4 mm fixed and variable angle locking screws provide a stable and lasting head‐locking mechanism. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:949–952, 2016.     

Pre‐programmed robotic osteotomies for fibula free flap mandible reconstruction: A preclinical investigation

Bony free flap reconstruction of the facial skeleton remains a challenging area of reconstructive surgery. Despite technological advances that have aided planning and execution of these procedures, surgical inaccuracy is not insignificant. One source of error that has not been wholly addressed is that attributable to a human operator. In this study, we investigate the feasibility and accuracy of performing osteotomies robotically in pre‐programmed fashion for fibula free flap mandible reconstruction as a method to reduce inaccuracies related to human error. A mandibular defect and corresponding free fibula flap reconstruction requiring six osteotomies were designed on a CAD platform. A methodology was developed to translate this virtual surgical plan data to a robot (KUKA, Augsburgs, Germany), which then executed osteotomies on three‐dimensional (3D) printed fibula flaps with the aid of dynamic stereotactic navigation. Using high‐resolution computed tomography, the osteotomized segments were compared to the virtually planned segments in order to measure linear and angular accuracy. A total of 18 robotic osteotomies were performed on three 3D printed fibulas. Compared to the virtual preoperative plan, the average linear variation of the osteotomized segments was 1.3 ± 0.4 mm, and the average angular variation was 4.2 ± 1.7°. This preclinical study demonstrates the feasibility of pre‐programmed robotic osteotomies for free fibula flap mandible reconstruction. Preliminarily, this method exhibits high degrees of linear and angular accuracy, and may be of utility in the development of techniques to further improve surgical accuracy. © 2015 Wiley Periodicals, Inc. Microsurgery 36:246–249, 2016.     

Alcohol use and the wage returns to education and work experience

Despite a widely held belief that alcohol use should negatively impact wages, much of the literature on the topic suggests a positive relationship between nonproblematic alcohol use and wages. Studies on the effect of alcohol use on educational attainment have also failed to find a consistent, negative effect of alcohol use on years of education. Thus, the connections between alcohol use, human capital, and wages remain a topic of debate in the literature. In this study, we use the 1997 cohort of the National Longitudinal Survey of Youth to estimate a theoretical model of wage determination that links alcohol use to wages via human capital. We find that nonbinge drinking is associated with lower wage returns to education whereas binge drinking is associated with increased wage returns to both education and work experience. We interpret these counterintuitive results as evidence that alcohol use affects wages through both the allocative and productive efficiency of human capital formation and that these effects operate in offsetting directions. We suggest that alcohol control policies should be more nuanced to target alcohol consumption in the contexts within which it causes harm.