Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Doctor of Philosophy

Program

Health and Rehabilitation Sciences

Collaborative Specialization

Musculoskeletal Health Research

Supervisor

Séguin, Cheryle A.

2nd Supervisor

Battié, Michele C.

Abstract

Problem: Diffuse idiopathic skeletal hyperostosis (DISH) is a common musculoskeletal condition yet its etiology, early and progressive disease features, and clinical implications are poorly understood. The purpose of this dissertation was to investigate the imaging features associated with the continuum of DISH.

Methods: A retrospective study design was used to evaluate thoracic computed tomography scans from a population in Minnesota, United States. Female and male individuals ≥20 years of age were examined for imaging features of DISH and early-phase DISH. The extent of ectopic bridging between each vertebrae was scored. Subsequently, the individuals with repeated computed tomography scans of the thoracic spine were evaluated for changes in imaging features over time. Lastly, a cohort of cadaveric human thoracic vertebral column specimens were studied to characterize pathological mineralization of the costovertebral joint (CVJ) and its association with DISH.

Findings: DISH was detected in 14.2% of the sample (7.4% of females, 20.9% of males, average age of 78 years) and early-phase DISH was detected in 13.2% of the sample (10.4% of females, 15.8% of males, average age 73 years). The change to early-phase DISH was characterized by new ectopic bridging at previously unaffected regions. Progression in the severity of DISH was characterized by increased bridge scores in regions that were previously affected. Microcomputed tomography demonstrated that ectopic bridging of the CVJ was associated with DISH and intra-articular CVJ mineralization was associated with early-phase DISH.

Significance: Insight into clinical implications of DISH were uncovered through our population-based research. We reported that DISH or early-phase DISH are present in one out of three individuals over the age of 40, with increased prevalence of DISH among males of advanced age. Importantly, we reported on the spatiotemporal changes across the continuum of DISH that differ based on the stage of development. We also identified a potential link between DISH and CVJ mineralization, which may contribute to a modified diagnostic criteria to improve clinical detection. These findings may facilitate improved detection and reporting of DISH in the clinic and, in turn, enhance clinical outcomes for people living with DISH.

Summary for Lay Audience

Arthritis-related musculoskeletal disorders are leading causes of pain and disability worldwide. Back pain and disorders of the spine are especially burdensome. Diffuse idiopathic skeletal hyperostosis (DISH)—a common spine condition—is characterized by irreversible formation of bone-like bridges that connect the bones of the spine. It is estimated based on research from 25 years ago that 15 to 25% of North Americans over 50 years of age are affected by this condition. Importantly, health professionals are often unfamiliar with DISH, so it is often mis- or under-diagnosed. Symptoms generally include back pain and stiffness, and in severe cases, DISH can lead to pinched nerves or obstruct swallowing. The cause of the condition is unknown and there are no effective treatments. Surgery can be performed to remove the mineral bridges, but the recurrence of DISH is extremely high. This poor knowledge and unmet clinical need underscore the necessity of further research.

Our research was designed to address four overarching research questions:

  1. What is the current prevalence of DISH and early-phase DISH in a North American population?
  2. How often do radiologists report on the imaging features of DISH?
  3. How do the bone-like bridges associated with DISH change over time as detected by medical images?
  4. What are additional joint structures that could be used to better define DISH?

Using medical records and clinical images, we aimed to determine the impact of DISH along its disease stages across the lifespan. Our studies showed that DISH occurs in one in four people over the age of 60 years and that more than one third of people over 40 years-of-age displayed either early-phase DISH or DISH. We studied individuals with multiple medical images to learn about changes in DISH over time. Our results identified unique clinical features at different points along the continuum of the disease. Lastly, our new findings show that bony changes at the rib joints are also associated with DISH.

Together, these findings contribute to an important investigation of the clinical features associated with DISH along its continuum with the goal of improving clinical awareness and early detection.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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