Ron N. Alkalay, Ph.D.

Instructor, Orthopedic Surgery  

Phone:  (617) 667-5185

Fax: (617) 667-7175

Email: ralkalay@bidmc.harvard.edu

Background

Dr. Alkalay received his Ph.D. degree from the IRC in Biomedical materials at London University in 1997 and has been associated with the laboratory ever since.  In 2001, Dr Alkalay was appointed as an Instructor in Orthopedic Surgery at Harvard Medical School and as affiliated faculty position both at Harvard DEAS and HST/MIT in 2002.

Research Background

Dr Alkalay’s research is directed at understanding the structural properties and mechanical behavior of musculoskeletal tissues underlying the function of the healthy spine and the effect of age, disease and trauma on these tissues. These interests naturally extend to the development and assessment of new treatment modalities, imaged based diagnostic tools and the evaluation and development of spinal instrumentation. This work has four areas:

1. Biomechanics of vertebral failure
Vertebral fractures caused by bone fragility or pathology, result in a patient population exhibiting prolonged and intractable pain and significant morbidity. In the case of metastatic disease of the spine, such fractures present a significant complication which may require immediate surgical intervention. Within the framework of a spinal unit, my research focuses on 1) Exploring the effect of constituent tissues and regional based anatomy of the vertebra on the structural response and failure processes of intact vertebra and the post-failure behavior of a fractured vertebra in response to time-dependent and time varying functional loading. These data will offer insight into the effect of bone fragility and bone pathology on the relative structural roles of trabecular bone and the vertebral cortex in constituting the mechanical response of the spine. 2) Developing Computed Tomography and Magnetic Resonance imaging methods to identify vertebra at risk for failure, and 3) Developing new treatment modalities and investigating their efficacy for palliative, as well as prophylactic treatment.

2. Biomechanics of intervertebral disk degeneration
Intervertebral disc disease has been significantly linked to low back pain, a major health problem in the US . Although little is known about the etiology and progression of this disease, the marked degradation in composition, structural and material properties of the disc’s tissues results in a significant loss in its static, dynamic and visco-elastic mechanical response. Current work is aimed at three main topics. 1) Develop MR derived diffusion measurement protocols to non-invasively quantify the effect of degenerative changes within the disc on its functional competence. 2) Elucidate the relationship between the local mechanics of annulus tissue, from laminar level to a full annulus tissue, and the global structural response of this tissue as affected by the composition and structure of this tissue. 3) Investigate the role of the disruption of nutritional pathways, mediated through the vertebral endplate, as a mechanism underlying the initiation of intervertebral disc degeneration.

3. Biomechanics of spinal fusion
Spine fusion, the process of creating a solid bone union between two adjacent vertebrae, is the most common surgical treatment for the painful and unstable spine. In recent years, rapid advances in our understanding of the biology underlying the process of bone remodeling and healing, have led to a strong commercial and clinical drive to utilize artificial bone graft products. Although showing promise in animal models when used to augment autologus bone grafts, clinical results in the elderly spine are less favorable. Our previous work demonstrated the importance of competing rates between the dissolution of bone grafts and the rate of new bone formation. In particular, we established a lower boundary for the rate of bone graft dissolution, below which the likelihood of bone formation rapidly diminishes. Current efforts are aimed at elucidating the role of the mechanical environment in effecting the biological processes of bone fusion.

4. Spinal instrumentation
Internal spinal fixation devices are typically employed as mechanical adjuncts to provide initial stability and surgical correction. Despite thirty years of clinical use and extensive research into the in vitro performance of such devices, severe clinical problems remain both in the failure of fixation devices to provide an optimal mechanical environment to enhance bone healing and in the mal-union of bone fusion mass, particularly in the osteoporotic spine. Current work, involving active industrial and clinical collaborations, is aimed at improving the design of internal spinal and intervertebral cages systems.