Skeletal metastases most frequently affect the vertebral column and may lead to severe consequences including fracture. Clinical management of skeletal metastases often utilizes a multimodal treatment approach, including bisphosphonates (BPs). Previous work has demonstrated the synergistic potential of photodynamic therapy (PDT) in combination with BP in treating osteolytic disease through structural, histologic, and destructive mechanical testing analyses. Recent work has developed and validated image-based methods that may be used to non-destructively determine mechanical stability in whole bones, and enable their use for additional (i.e. histologic) analysis. In this work we use an intensity-based 3D image registration technique to compare the strain patterns throughout untreated control and BP + PDT treated rnu/rnu rat spinal motion segments with osteolytic metastases. It was hypothesized that the combination treatment will reduce average and maximum strain values and restore the pattern of strain to that of healthy vertebrae. Mean, median, and 90th percentile strains in the control group were significantly higher than the treatment group. High strain areas in both groups were observed around the endplates; in the control group, large areas of high strains were also observed around the lesions and adjacent to the dorsal wall. Absence of high strains adjacent to the dorsal wall (similar to healthy vertebrae) may correspond to a reduced risk of burst fracture following BP + PDT therapy. This study demonstrates the application of non-destructive image analysis to quantify the positive mechanical effects of combined BP + PDT treatment in the metastatic spine.
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Similar content being viewed by others Explore related subjectsDiscover the latest articles and news from researchers in related subjects, suggested using machine learning. AbbreviationsPhotodynamic therapy
Bisphosphonates
Benzoporphyrin derivative monoacid
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Support for this project was received from the Ontario Institute for Cancer Research. The authors would also like to thank Michael Meguid for his assistance with the micro-imaging on this study.
Author information Authors and AffiliationsOrthopedic Biomechanics Laboratory, Sunnybrook Health Sciences Centre, 2075 Bayview Ave. UB19, Toronto, ON, M4N 3M5, Canada
Seyed-Parsa Hojjat, Emily Won, Michael R. Hardisty, Margarete K. Akens, Lisa M. Wise-Milestone & Cari M. Whyne
Correspondence to Cari M. Whyne.
Additional informationAssociate Editor James Tunnell oversaw the review of this article.
About this article Cite this articleHojjat, SP., Won, E., Hardisty, M.R. et al. Non-Destructive Evaluation of the Effects of Combined Bisphosphonate and Photodynamic Therapy on Bone Strain in Metastatic Vertebrae Using Image Registration. Ann Biomed Eng 39, 2816–2822 (2011). https://doi.org/10.1007/s10439-011-0370-x
Received: 18 March 2011
Accepted: 23 July 2011
Published: 05 August 2011
Issue Date: November 2011
DOI: https://doi.org/10.1007/s10439-011-0370-x
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