Orthopedics Commons^™

Increased Hif-2Α Activity In The Nucleus Pulposus Causes Intervertebral Disc Degeneration In The Aging Mouse Spine, Shira N Johnston, Maria Tsingas, Rahatul Ain, Ruteja A Barve, Makarand Risbud

Department of Orthopaedic Surgery Faculty Papers

Hypoxia-inducible factors (HIFs) are essential to the homeostasis of hypoxic tissues. Although HIF-2α, is expressed in nucleus pulposus (NP) cells, consequences of elevated HIF-2 activity on disc health remains unknown. We expressed HIF-2α with proline to alanine substitutions (P405A; P531A) in the Oxygen-dependent degradation domain (HIF-2αdPA) in the NP tissue using an inducible, nucleus pulposus-specific K19^CreERT allele to study HIF-2α function in the adult intervertebral disc. Expression of HIF-2α in NP impacted disc morphology, as evident from small but significantly higher scores of degeneration in NP of 24-month-old K19^CreERT; HIF-2α^dPA (K19-dPA) mice. Noteworthy, comparisons of grades …

Multilevel Ossification Of The Posterior Longitudinal Ligament Causing Cervical Myelopathy: An Observational Series Of North American Patients, Jonathan A. Ledesma, Tariq Z. Issa, Mark J. Lambrechts, Cannon Greco Hiranaka, Khoa Tran, Patrick O'Connor, Jose A. Canseco, Alan S. Hilibrand, Christopher K. Kepler, Todd J. Albert, Alex R. Vaccaro, Gregory D. Schroeder, David Greg Anderson

Department of Orthopaedic Surgery Faculty Papers

BACKGROUND: Few studies regarding ossification of the posterior longitudinal ligament (OPLL) outside of Asia currently exist in the literature. A set of patients with multilevel cervical OPLL causing symptomatic myelopathy or radiculopathy from a North American sample is analyzed.

OBJECTIVE: The objective of this study was to describe the demographics, radiographic findings, and surgical outcomes of a cohort of North American patients with degenerative spondylosis presenting for operative management of multilevel (>3 segments) cervical OPLL.

MATERIALS AND METHODS: Forty-three patients diagnosed with multilevel cervical OPLL and degenerative spondylosis presenting with symptomatic cervical myelopathy or radiculopathy were surgically treated over …

Cross-Sectional Area Of The Longus Colli And Cervical Degenerative Spondylolisthesis: A Retrospective Review Evaluating This Anatomic Consideration, Khoa Tran, Aditya Mazmudar, Taylor Paziuk, Mark J. Lambrechts, Eric Tecce, Olivia Blaber, Kamil Okroj, Brian A Karamian, Jose A Canseco, Jeffrey A Rihn, Alan Hilibrand, Christopher Kepler, Alexander R. Vaccaro, Gregory D. Schroeder

Department of Orthopaedic Surgery Faculty Papers

Background: Limited literature is available to define the impact of the longus colli muscle, a deep flexor of the spine, on cervical spine stability despite its close proximity to the vertebrae. Aims and Objectives: The purpose of this study was to determine if longus colli cross-sectional area (CSA) is associated with the severity preoperative cervical degenerative spondylolisthesis. Materials and Methods: Patients undergoing elective anterior cervical discectomy and fusion (ACDF) for cervical spondylolisthesis between 2010-2021 were retrospectively identified. Longus colli cross-sectional areas (CSA) were measured from preoperative MRI images at the C5 level. Preoperative spondylolisthesis measurements were recorded with cervical radiographs. …

Abcc6 Null Mice-A Model For Mineralization Disorder Pxe Shows Vertebral Osteopenia Without Enhanced Intervertebral Disc Calcification With Aging, Paige K Boneski, Vedavathi Madhu, Ryan Tomlinson, Irving Shapiro, Koen Van De Wetering, Makarand V Risbud

Department of Orthopaedic Surgery Faculty Papers

Chronic low back pain is a highly prevalent health condition intricately linked to intervertebral disc degeneration. One of the prominent features of disc degeneration that is commonly observed with aging is dystrophic calcification. ATP-binding cassette sub-family C member 6 (ABCC6), a presumed ATP efflux transporter, is a key regulator of systemic levels of the mineralization inhibitor pyrophosphate (PPi). Mutations in ABCC6 result in pseudoxanthoma elasticum (PXE), a progressive human metabolic disorder characterized by mineralization of the skin and elastic tissues. The implications of ABCC6 loss-of-function on pathological mineralization of structures in the spine, however, are unknown. Using the Abcc6 -/- …

Genetic Murine Models Of Spinal Development And Degeneration Provide Valuable Insights Into Intervertebral Disc Pathobiology., J. Melrose, S. Tessier, M. V. Risbud

Department of Orthopaedic Surgery Faculty Papers

Disc degeneration and associated back and neck pain elicits a substantial burden on healthcare systems and the individuals affected, necessitating the development of novel therapeutic strategies. This goal can only be achieved by a better understanding of intervertebral disc development, homeostasis and pathogenesis. A number of genetic and in-bred murine models are reviewed to underscore the importance of the mouse as an animal model of choice for the assessment of intervertebral disc pathobiology. Appraisals of the differences between mouse and human musculoskeletal systems and proteoglycan structures are also included. A number of important target pathways and molecules have been identified, …

Ultrasound-Triggered Antibiotic Release From Peek Clips To Prevent Spinal Fusion Infection: Initial Evaluations., Lauren J. Delaney, Daniel Macdonald, Jay Leung, Keith Fitzgerald, Alex M. Sevit, John R. Eisenbrey, Neil Patel, Flemming Forsberg, Christopher K. Kepler, Taolin Fang, Steven M. Kurtz, Noreen J. Hickok

Department of Orthopaedic Surgery Faculty Papers

Despite aggressive peri-operative antibiotic treatments, up to 10% of patients undergoing instrumented spinal surgery develop an infection. Like most implant-associated infections, spinal infections persist through colonization and biofilm formation on spinal instrumentation, which can include metal screws and rods for fixation and an intervertebral cage commonly comprised of polyether ether ketone (PEEK). We have designed a PEEK antibiotic reservoir that would clip to the metal fixation rod and that would achieve slow antibiotic release over several days, followed by a bolus release of antibiotics triggered by ultrasound (US) rupture of a reservoir membrane. We have found using human physiological fluid …

What Are Biofilms?, Noreen J. Hickok

Department of Orthopaedic Surgery Faculty Papers

No abstract provided.

Posterior Longitudinal Ligament Status In Cervical Spine Bilateral Facet Dislocations, John A. Carrino, Geoffrey L. Manton, William B. Morrison, Alex R. Vaccaro, Mark E. Schweitzer, Adam E. Flanders

Department of Orthopaedic Surgery Faculty Papers

Objective: It is generally accepted that cervical spine bilateral facet dislocation results in complete disruption of the posterior longitudinal ligament. The goal of this study was to evaluate the integrity of numerous spine-stabilizing structures by MRI, and to determine if any associations between injury patterns exist with respect to the posterior longitudinal ligament status.

Design: Retrospective case series.

Patients: A retrospective review was performed of 30 cervical spine injury subjects with bilateral facet dislocation. Assessment of 1.5T MRI images was carried out for: intervertebral disc disruption, facet fracture, and ligamentous disruption. Statistical analyses were performed to evaluate for associations between …