Kelly Laboratory
Laboratory Focus
The personnel of the Spinal Biomechanics Laboratory study the mechanical behavior of the spine in its normal condition and after injury, disease, or surgical intervention. The lab works closely with clinical neurosurgeons in the Division of Neurosurgery. Neurosurgical residents, fellows, and Barrow staff perform experiments on specially prepared human cadaveric spines. Injuries that mimic those seen in patients are induced in the specimens, and surgical procedures identical to those in the operating room are performed.
Before and after injuring or performing surgery on a cadaveric spine, the specimen is tested mechanically by applying carefully controlled loads through a system of cables and pulleys or belt, motor, and weights while measuring the three-dimensional motion using an optical system. The loads are similar to the maximum forces a person applies to the spine during daily activities.
The laboratory’s principal goal is to improve healthcare by investigating how different surgical procedures affect the mechanical response of the spine—particularly, what effect different procedures have on spinal stability. Studies like the ones performed in our laboratory are published to help surgeons decide how best to treat patients requiring spinal surgery; these studies may lead to new and better techniques or devices for spinal surgery.
Biomechanics of Artificial Discs
Although few artificial intervertebral discs are currently on the market in the US due to the slow FDA approval process, many are under development by different companies in the US and elsewhere. The biomechanics lab initiated a number of protocols with these companies to evaluate their devices. The ultimate goal is to publish our findings to benefit patients and doctors in understanding how the spine will move differently after implantation of each device. As described on the Testing Techniques page, the BNI lab has at its disposal several advanced testing methods unavailable at other labs and is hoping to set new standards in how such experiments are performed.
Dr. Crawford published a critique of the most recently published studies on biomechanical testing of cervical artificial discs.
Ongoing research includes measurement of range of motion, zone of laxity, coupling patterns, axis of rotation, and facet loads at levels of the spine in specimens with artificial intervertebral discs implanted. One of the hypothetical benefits of implanting an artificial disc instead of fusing a level of the spine is that there is less of a “lever arm” on the adjacent normal levels, and so there is less chance of these normal levels degenerating later in life. New research in the biomechanics lab focuses on studying the biomechanical effects on adjacent levels in conditions of natural disc versus fusion versus artificial disc. This new research will make use of a complex testing apparatus recently designed in collaboration with a local engineering firm that generates external loads on spine representing both muscles and gravity.
Surgical Planning and Rapid Prototyping of the Spine
The biomechanics lab was awarded a grant from the National Institutes of Health to develop a computerized surgical planning tool, which is now in the late stages of development, utilizing a desktop haptic device. With this system, a 3D computer model of the patient’s spine and pathology is generated from the patient’s computerized tomography scan. The surgeon then performs virtual surgery to correct the pathology.
With haptics, the surgeon feels forces during simulated drilling and bone realignment that help to predict the experience that will be encountered in the operating room. After the surgeon completes the mock surgery, computerized analysis is applied to fine tune the surgical plan, and rapid-prototyped spine models help communicate surgical planning information to the patient. Rapid prototyped drill guides are also used to improve accuracy of screw insertion. (See an abstract of this grant on the NIH website)
Assistant Professor, Neurobiology and Neurosurgery
Contact Information
Brian Kelly, PhD
Assistant Professor, Spinal Biomechanics
350 West Thomas Road
Phoenix, Arizona 85013
Brian.Kelly@DignityHealth.org
Robert H. Chamberlain Memorial
Biomechanics Fellowship
The Spinal Biomechanics Laboratory offers a one-year fellowship in biomechanics to international surgeons or surgeons-in-training. The position runs from July 1 through the following June 30 and pays a monthly stipend.
Interested applicants should send their curriculum vitae and a cover letter describing their proposed course of study to Dr. Brian Kelly for consideration.
1973-2005
Research Technician
Current Biomechanics Fellows
- Bernardo de Andrada, MD
Rio de Janeiro, Brazil
Former Biomechanics Fellows
2019-2020
Piyanat Wangsawatwong, MD
Bangkok, Thailand
2016-2017
Ram Kumar Menon
Kerala, India
2013-2015
Hector Soriano-Baron
Mexico City, Mexico
2012-2013
Nestor Rodriguez, MD
Mexicali, Mexico
2011-2012
Luis Pérez-Orribo, MD
Tenerife, Canary Islands, Spain
2010-2011
Marco Túlio Domingos Silva e Reis, MD
Belo Horizonte, Brazil
2009-2010
Felix Dominguez Cortinas, MD
Mexico City, Mexico
2008-2009
Ali A. Baaj, MD
Tampa, Florida
2007-2008
Bruno C. R. Lazaro, MD
Rio de Janeiro, Brazil
2006-2007
Mehmet Senoglu, MD
Kahramanmaras, Turkey
2005-2006
Sam Safavi-Abbasi, MD
Hannover, Germany
2005-2006
Seref Dogan, MD
Bursa, Turkey
2004-2005
Zafer Yüksel, MD
Kahramanmaras, Turkey
2003-2004
Adolfo Espinoza-Larios, MD
Hermosillo, Mexico
2002-2003
Hakan Bozkus, MD
Istanbul, Turkey
2001-2002
Luis E. Perez-Garza, MD
Tampico, Mexico
1999-2001
Sung Chan Park, MD
Seoul, South Korea
Laboratory Publications
Development of a Definition of Postacute Sequelae of SARS-CoV-2 Infection.
Date: 06/2023
Authors: Tanayott Thaweethai, Sarah E Jolley, Elizabeth W Karlson, Emily B Levitan, Bruce Levy, Grace A McComsey, Lisa McCorkell, Girish N Nadkarni, Sairam Parthasarathy, Upinder Singh, Tiffany A Walker, Caitlin A Selvaggi, Daniel J Shinnick, Carolin C M Schulte, Rachel Atchley-Challenner, George A Alba, Radica Alicic, Natasha Altman, Khamal Anglin, Urania Argueta, Hassan Ashktorab, Gaston Baslet, Ingrid V Bassett, Lucinda Bateman, Brahmchetna Bedi, Shamik Bhattacharyya, Marie-Abele Bind, Andra L Blomkalns, Hector Bonilla, Hassan Brim, Patricia A Bush, Mario Castro, James Chan, Alexander W Charney, Peter Chen, Lori B Chibnik, Helen Y Chu, Rebecca G Clifton, Maged M Costantine, Sushma K Cribbs, Sylvia I Davila Nieves, Steven G Deeks, Alexandria Duven, Ivette F Emery, Nathan Erdmann, Kristine M Erlandson, Kacey C Ernst, Rachael Farah-Abraham, Cheryl E Farner, Elen M Feuerriegel, Judes Fleurimont, Vivian Fonseca, Nicholas Franko, Vivian Gainer, Jennifer C Gander, Edward M Gardner, Linda N Geng, Kelly S Gibson, Minjoung Go, Jason D Goldman, Halle Grebe, Frank L Greenway, Mounira Habli, John Hafner, Jenny E Han, Keith A Hanson, James Heath, Carla Hernandez, Rachel Hess, Sally L Hodder, Matthew K Hoffman, Susan E Hoover, Beatrice Huang, Brenna L Hughes, Prasanna Jagannathan, Janice John, Michael R Jordan, Stuart D Katz, Elizabeth S Kaufman, John D Kelly, Sara W Kelly, Megan M Kemp, John P Kirwan, Jonathan D Klein, Kenneth S Knox, Jerry A Krishnan, Andre Kumar, Adeyinka O Laiyemo, Allison A Lambert, Margaret Lanca, Joyce K Lee-Iannotti, Joyce K Lee-Ianotti, Brian P Logarbo, Michele T Longo, Carlos A Luciano, Karen Lutrick, Jason H Maley, Gail Mallett, Jai G Marathe, Vincent Marconi, Gailen D Marshall, Christopher F Martin, Yuri Matusov, Alem Mehari, Hector Mendez-Figueroa, Robin Mermelstein, Torri D Metz, Richard Morse, Jarrod Mosier, Christian Mouchati, Janet Mullington, Shawn N Murphy, Robert B Neuman, Janko Z Nikolich, Ighovwerha Ofotokun, Elizabeth Ojemakinde, Anna Palatnik, Kristy Palomares, Tanyalak Parimon, Samuel Parry, Jan E Patterson, Thomas F Patterson, Rachel E Patzer, Michael J Peluso, Priscilla Pemu, Christian M Pettker, Beth A Plunkett, Kristen Pogreba-Brown, Athena Poppas, John G Quigley, Uma Reddy, Rebecca Reece, Harrison Reeder, W B Reeves, Eric M Reiman, Franz Rischard, Jonathan Rosand, Dwight J Rouse, Adam Ruff, George Saade, Grecio J Sandoval, Jorge L Santana, Shannon M Schlater, Frank C Sciurba, Fitzgerald Shepherd, Zaki A Sherif, Hyagriv Simhan, Nora G Singer, Daniel W Skupski, Amber Sowles, Jeffrey A Sparks, Fatima I Sukhera, Barbara S Taylor, Larissa Teunis, Robert J Thomas, John M Thorp, Paul Thuluvath, Amberly Ticotsky, Alan T Tita, Katherine R Tuttle, Alfredo E Urdaneta, Daisy Valdivieso, Timothy M VanWagoner, Andrew Vasey, Monica Verduzco-Gutierrez, Zachary S Wallace, Honorine D Ward, David E Warren, Steven J Weiner, Shelley Welch, Sidney W Whiteheart, Zanthia Wiley, Juan P Wisnivesky, Lynn M Yee, Sokratis Zisis, Leora I Horwitz, Andrea S Foulkes
Biomechanical Effects of Facet Joint Violation after Single-level Lumbar Fusion with Transpedicular Screw and Rod Instrumentation
Date: 05/2023
Authors: Piyanat Wangsawatwong, Bernardo de Andrada Pereira, Jennifer N. Lehrman, Anna G. Sawa, Luke K. O’Neill, Jay D. Turner, Juan S. Uribe, Brian P. Kelly, B P Kelly
Biomechanical Assessment of a Novel Sharp-Tipped Screw for 1-Step Minimally Invasive Pedicle Screw Placement Under Navigation
Date: 04/2023
Authors: Bernardo de Andrada Pereira, Luke K. O’Neill, Anna G. Sawa, James J. Zhou, Piyanat Wangsawatwong, Jennifer N. Lehrman, Jakub Godzik, Alton J. Oldham, Jay D. Turner, Brian P. Kelly, B P Kelly, Juan S. Uribe
Rod Attachment Induces Significant Strain in Lumbosacral Fixation
Date: 02/2023
Authors: Anna G. Sawa, Piyanat Wangsawatwong, Jennifer N. Lehrman, Taylor Hostetler, Bernardo de Andrada Pereira, Jakub Godzik, Randall J. Hlubek, Juan S. Uribe, Jay D. Turner, Brian P. Kelly, B P Kelly
Predictors of Time to Aneurysm Repair and Mortality in Aneurysmal Subarachnoid Hemorrhage
Date: 10/2022
Authors: Tiffany O. Sheehan, Nicolle W. Davis, Yi Guo, Debra Lynch Kelly, B P Kelly, Brian P. Kelly, Saunjoo L. Yoon, Ann L. Horgas
In vitro testing of the spine provides valuable information to researchers and clinicians about how neurosurgical procedures affect spinal stability and motion (Crawford, 2002). The Spinal Biomechanics Laboratory has devised several novel techniques for experimentally testing cadaveric spines, enabling researchers at our institution to study spinal biomechanics in ways that were not possible at other institutions. Many of these techniques are incorporated in the custom software developed in the Spinal Biomechanics Laboratory. This software is now used not only at Barrow, but has also been provided by Barrow for use in other biomechanics laboratories at universities in the United States.
Local Coordinate Systems
In the Spinal Biomechanics Laboratory, a technique was devised to enable each level of the spine to be tracked and studied independently (Crawford and Dickman, 1997). With this technique, the researcher points to specific vertebral landmarks with a probe in which optical markers are embedded. Custom testing software performs spatial transformations to align these landmarks with appropriate Cartesian coordinate system of the vertebra. Angular data can then be plotted in real time in individual local coordinate systems of multiple spinal levels during testing.
Three-Dimensional Spinal Angle Calculation
Publications from the Spinal Biomechanics Laboratory have contributed to the understanding of how three-dimensional (3D) joint angles are best calculated. In Crawford et al, 1996, the differences and similarities of two methods for calculating 3D joint angles, projection angles and Euler angles, were described, and a method was proposed by which the most appropriate Euler angle sequence or projection angle set can be selected for the spine and other joints of the body. In Crawford et al, 1999, a new 3D angle technique, the “tilt/twist” method, which has advantages over both the projection and Euler methods, was developed. The custom software developed in the Spinal Biomechanics Lab uses this tilt/twist method technique to display spinal angles in real time during testing.
Illustrations reprinted from Human Movement Science, 15(1), Crawford NR, Yamaguchi GT, Dickman CA: Methods for determining spinal flexion/extension, lateral bending, and axial rotation from marker coordinate data: Analysis and refinement, pg.55-78, 1996, with permission from Elsevier.
