Age is Associated with Level of First-Time Anterior Cervical Discectomy and Fusion: An Ordinal Analysis of Factors Influencing Timing of Cervical Degeneration.

BACKGROUND: Symptomatic cervical spondylosis is often treated with anterior cervical discectomy and fusion (ACDF). However, few factors can predict which cervical level will degenerate and require intervention. This analysis evaluates preprocedural factors associated with level of first-time single-level ACDF. METHODS: We performed a retrospective analysis of patients who underwent single-level ACDF without prior history of spine surgery. Mann Whitney U-tests and Spearman rank-order correlation were performed for analyses of associations between variables of interest and ACDF level. Adjusted odds-ratios were calculated by proportional-odds logistic regression, with age, sex, body mass index, current tobacco use, history of neck trauma, preoperative radicular symptoms, and preoperative myelopathic symptoms as covariates. RESULTS: One hundred forty-one patients met inclusion criteria, and age demonstrated a negative correlation with ACDF level, such that younger patients tended to have ACDF performed at inferior subaxial levels (P = 0.0006, rho = -0.31, moderately strong relationship). Patients with preoperative radicular symptoms and myelopathic symptoms were more likely to have ACDF performed at inferior (P = 0.0001) and superior (P < 0.0001) levels, respectively. Patient sex, body mass index, current tobacco use, and history of neck trauma were not predictive of ACDF level. When adjusting for the above variables in a proportional-odds ordinal logistic regression model, a one-year increase in age conferred a 4% increase in the odds of requiring an ACDF at a given superior level compared to the adjacent inferior level. CONCLUSIONS: Age is correlated with level of first-time single level ACDF. Individual subaxial levels may have unique biomechanical properties that influence degeneration.

Applying 3-Dimensional Printing and Modeling for Preoperative Reconstruction and Instrumentation Placement Planning in Complex Deformity Surgery.

BACKGROUND: Advances in three-dimensional (3D) printing technology have enabled the development of customized instrumentation and surgical training platforms. However, no existing studies have assessed how patient-specific 3D-printed spine models can facilitate patient education and operative planning in complex spinal deformity correction. OBJECTIVE: To present a cost-effective technique for constructing personalized 3D-printed spine models for patients with severe spinal deformities and to outline how these models can promote informed consent, trainee education, and planning for instrumentation placement and alignment correction. METHODS: We present 2 patients who underwent surgical correction of progressive thoracolumbar deformities. Full-scale 3D-printed models of each patient's spine were produced preoperatively and used during clinic evaluations, surgical planning, and as intraoperative references. RESULTS: Each model took 9 days to build and required less than 60 US dollars of material costs. Both patients were treated with a posterior approach and contiguous multilevel osteotomies. Postoperatively, their alignment parameters and neurological deficits improved. CONCLUSION: Personalized 3D-printed spine models can aid in patient education, surgical training, visualization, and correction of complex spinal deformities.

Use of Anti-Warnings to Falsely Reassure Downstream Users: An Asbestos Example.

Product warnings are theoretically designed to reduce injuries associated with occupational, environmental, or consumer product exposures. Unfortunately, in an effort to protect sales, some companies have produced media and information to falsely reassure their customers about the risks associated with their products. These tactics have been termed "anti-warnings." We reviewed corporate documents uncovered in litigation alongside other historical publications to ascertain the types of anti-warnings used by Union Carbide Corporation (UCC) regarding their asbestos products. Our review finds that UCC went to great lengths to confuse their customers and make their particular asbestos product-which contained short-fiber, chrysotile asbestos-look safe. We discuss three primary communications methods UCC used: industry-produced publications, sales force direct communication with customers, and public speeches. These examples provide further insight into how corporations encourage uncertainty about the risks associated with their products. Understanding anti-warning methods is critical for the implementation of future policies that protect consumer, worker, and environmental health.

Hippo Signaling Pathway Dysregulation in Human Huntington's Disease Brain and Neuronal Stem Cells.

The Hippo signaling pathway is involved in organ size regulation and tumor suppression. Although inhibition of Hippo leads to tumorigenesis, activation of Hippo may play a role in neurodegeneration. Specifically, activation of the upstream regulator, mammalian sterile 20 (STE20)-like kinase 1 (MST1), reduces activity of the transcriptional co-activator Yes-Associated Protein (YAP), thereby mediating oxidative stress-induced neuronal death. Here, we investigated the possible role of this pathway in Huntington's disease (HD) pathogenesis. Our results demonstrate a significant increase in phosphorylated MST1, the active form, in post-mortem HD cortex and in the brains of CAG knock-in HdhQ111/Q111 mice. YAP nuclear localization was also decreased in HD post-mortem cortex and in neuronal stem cells derived from HD patients. Moreover, there was a significant increase in phosphorylated YAP, the inactive form, in HD post-mortem cortex and in HdhQ111/Q111 brain. In addition, YAP was found to interact with huntingtin (Htt) and the chaperone 14-3-3, however this interaction was not altered in the presence of mutant Htt. Lastly, YAP/TEAD interactions and expression of Hippo pathway genes were altered in HD. Together, these results demonstrate that activation of MST1 together with a decrease in nuclear YAP could significantly contribute to transcriptional dysregulation in HD.