Spinal Studies

• Principal Investigator: Steven A. Gard, PhD
• Co-Investigators: Stefania Fatone, PhD, and Aruna Ganju, MD**
• Funded by: Department of Veterans Affairs (VA) 
• Status: Completed 

** Department of Neurological Surgery, Northwestern University

The ability to walk efficiently is integral to the performance of many activities of daily living and the ability to function independently. Self-reported physical function of people with spinal problems is low and people with abnormal posture had poorer functional performance during standardized tests. It has been suggested that the spine plays an important role during ambulation as a shock absorber and energy saving system. Studies of energy expenditure in people with spine pathologies are limited: increased oxygen uptake has been reported in subjects with scoliosis, irrespective of the degree of spinal curvature; decreased endurance has been reported in women with lumbar spine deformity; and increased energy expenditure during standing has been reported in women with osteoporosis. It is not clear what the impact of surgery is on energy expenditure in people with spinal deformity.

Degenerative spine disease affects many Americans and the incidence/prevalence of this condition is increasing as the population ages, incurring a significant cost to both the individual and society. Spinal column degeneration results in structural deformity, neurologic compromise, and considerable pain; for many, these symptoms result in surgery. Surgery stabilizes and re-aligns the spine, thus reducing pain. Spinal deformity alters cranio-spino-pelvic orientation and leads to lower limb compensatory mechanisms to maintain an upright posture, which may be associated with increased energy expenditure. The purpose of this project is to evaluate the impact of surgery on quality of life as it relates to the effort and efficiency of walking in patients with degenerative spine disease.

• Co-Investigator: Stefania Fatone, PhD
• Project Director: Rebecca Stine, MS
• Post-doctoral Fellow: Pranitha Gottipati, PhD; Azucena Rodriguez, PhD** (Fellowship funded by National Institutes of Health-Institutional Research and Academic Career Development Award, K12 Program)
• Funded by: National Institute on Disability and Rehabilitation Research (NIDRR) H133E080009
• Status: Completed 

** Department of Electrical Engineering, Northwestern University

Low back pain is a prevalent condition among the general population with causes ranging from musculoskeletal impairment, gait abnormalities, excessive activity or overuse, along with a variety of other issues. Low back pain has been rated as more bothersome than either phantom limb pain or residual limb pain by persons with lower extremity amputations.

Although it has been suggested that gait abnormalities may contribute to low back pain, there have been limited investigations that have attempted to correlate low back pain to kinematic variables, especially spinal motions. Typically, gait analysis models disregard the spine entirely or regard it as a single rigid structure. Data on regional spinal movements, in conjunction with lower limb data, associated with walking are scarce. As such our understanding of spinal motion in both able-bodied persons and those with amputation has been limited. Yet understanding spinal motion and compensations during walking would improve our comprehension of the factors contributing to low back pain and lead to interventions designed to alleviate low back pain.

Specific Objectives

We intend to investigate whether there are kinematic differences during walking in persons with transfemoral amputations that have low back pain compared to persons with transfemoral amputations without low back pain. This study has two objectives: (1) to compare lower body kinematics and spinal kinematics in persons with transfemoral amputations with and without low back pain, and (2) to determine if there are any kinematic differences between the two groups that help explain the presence of low back pain in prosthesis users. The Figure shows our spine kinematic model marker set and wireframe model (see Konz et al. 2006).

Clinical Implications

It has been established that low back pain is prevalent in persons with transfemoral amputations. Identification of differences in motion, especially spinal motion, during walking between transfemoral amputees with and without low back pain will improve our understanding of the contributing factors and suggest potential interventions that may decrease the prevalence of low back pain in persons with transfemoral amputation.

References

• Konz R, Fatone S, Stine R, Ganju A, Gard S and Ondra S (2006) A Kinematic Model to Assess Spinal Motion During Walking. Spine, 31(24):E898-E906. 17108818

Publications

• Fatone S, Stine R, Gottipati P, Dillon M (2015) Pelvic and Spinal Motion during Walking in Persons with Transfemoral Amputation with and without Low Back Pain. American Journal of Physical Medicine and Rehabilitation, Oct 22. [Epub ahead of print]. PMID: 26495814.

Presentations

• Stine R, Gottipati P, Dillon M, Fatone S (2016) Pelvic and Spinal Motion during Walking in Persons with Transfemoral Amputation with and without Low Back Pain. NUPOC Biennial Symposium for the German-Speaking Travel Fellows of Initiative '93, February 25, Chicago, IL.
• Rodriguez A, Stine R, Fatone S (2011) Spinal Motion during Walking in Persons with Transfemoral Amputation with and Without Low Back Pain, in 1st Annual Movement and Rehabilitation Sciences (MRS) Training Day. Northwestern University, August 23, Chicago, IL.
• Rodriguez A, Stine R, Fatone S (2011) Spinal motion during walking in persons with unilateral transfemoral amputation with and without low back pain. in Midwest Chapter of the American Academy of Orthotists and Prosthetists Fall Meeting, November 12, Hickory Hills IL.
• Rodriguez A, Stine R, Fatone S, Gard S (2012) Spinal motion during walking in persons with unilateral transfemoral amputation with and without low back pain. in 38th American Academy of Orthotists and Prosthetists Annual Meeting and Scientific Symposium, March 21-24, Atlanta, GA.
• Rodriguez A, Stine R, Gard S, Fatone S (2012) Spinal motion during walking in persons with unilateral transfemoral amputation with and without low back pain. American Academy of Orthotists and Prosthetists Webinar Series, August 22. Archived online at: http://www.oandp.org/olc/course_video.asp?frmCourseId=4E0ABC59-B731-4646-9756-16D5B3F9FD42 
• Fatone S, Stine R, Rodriguez A, Gard S (2013) Spinal motion during walking in persons with unilateral transfemoral amputation with and without low back pain. 14th World Congress of the International Society of Prosthetics and Orthotics, February 4-7, Hyderabad, India.

• Principal Investigator: Tyler Koski, MD**
• Project Director: Pranitha Gottipati, PhD**
• Co-Investigators: Stefania Fatone, PhD, Rebecca Stine, MS, and Aruna Ganju, MD**
• Funded by: Medtronic Sofamor-Danek, Inc.
• Status: Completed

**Department of Neurosurgery, Northwestern University

The outcomes of spinal realignment surgery are assessed primarily on static x-rays of the spine with limited understanding of the effect of spinal alignment on functional activities. The purpose of this project is to compare the C7/S1 sagittal alignment assessed by x-ray (see Figure) with that calculated non-invasively in the motion analysis laboratory in able-bodied adults. If the static sagittal alignment results from both methods are similar, the motion analysis technology can be used to assess sagittal alignment during walking. We will also assess the assumption that the C7/S1 plumb line approximates the location of the body center of mass (BCOM) in the sagittal plane.

Methods

C7 and S1 vertebral positions and the BCOM position are calculated using the data collected from reflective markers placed on subjects' limbs, back and head. Then we address our hypotheses by comparing able-bodied C7/S1 alignment data, acquired non-invasively in the motion analysis laboratory, with position data acquired via x-ray from another study led by Dr. Koski to establish normative values for x-ray based assessment of C7/S1 alignment.

Preliminary Results

Preliminary results from 14 subjects suggest that the difference between the average radiograph sagittal alignment results and the non-invasive method is less than 1cm. These preliminary results support our hypothesis that the two methods are comparable. The anterior-posterior distance between C7 and S1 vertebrae during walking appears to be considerably larger than static values. The mean absolute distance between the C7 plumb line and BCOM while standing and walking is 2.0 cm and 1.8 cm, respectively.

Reference

• Bernhardt M. Normal spinal anatomy: Normal sagittal plane alignment. In: The textbook of spinal surgery (2nd edition) (Eds. Bridwell K H and DeWald R L). Lippincott-Raven, Philadelphia 1997: 185-91.

• Co-Principal Investigators: Steven Gard, PhD, and Stephen Ondra, MD**
• Student Investigator: Devjani Saha, BS
• Co-Investigator: Stefania Fatone, PhD
• Funded by: Medtronic Sofamor-Danek, Inc.; and National Institute on Disability and Rehabilitation Research (NIDRR)

** Department of Neurosurgery, Northwestern University

The goal of this project is to better understand the role of trunk posture on the ability to maintain balance. In upright posture, the spine is aligned so that the head and trunk fall directly over the pelvis. Changes in spinal alignment resulting from spinal pathologies may displace the trunk center of mass (TCOM) with respect to the body's base of support. Sufficient displacement of the TCOM may adversely affect the body's ability to maintain upright posture and balance. Compensatory mechanisms, which are metabolically expensive, may then be necessary to restore balance. In order to improve our understanding of how sagittal malalignment of the spine affects stability, this study examined how trunk-flexed postures affect balance, dynamics, and energetics in able bodied individuals during standing and walking.

Methods

Motion and force plate data were collected for 14 able-bodied subjects standing and walking with upright and with 25±7° and 50±7° of trunk-flexion from the vertical. Trunk flexion was monitored in real time. Feedback in the form of auditory cues helped subjects maintain their trunk flexion angle within the desired range. Energy expenditure was also monitored at each posture during static standing.

Results

The results of the study suggested that kinematic adaptations, such as an increase in ankle plantarflexion and an increase in hip flexion during standing and sustained stance-phase knee flexion during walking, may be critical for balance control with trunk-flexed postures. Compensatory changes in lower extremity kinematics produced a posterior shift in the TCOM and brought the fore-aft position of the body center of mass closer to the center of the base of support. Sustained stance-phase knee flexion was associated with changes in the vertical ground reaction force (GRFv) profile, including an increase in the average rate of loading, a delay in the timing of the force valley minimum, and a decrease in the magnitude the second peak of the GRFv. Compensatory mechanisms may also have contributed to the observed increase in metabolic energy expenditure during static standing and the decrease in energy conservation during walking. The gait dynamics of able-bodied subjects walking with trunk flexion were similar to that of a patient who was unable to adequately compensate with hip and/or trunk extension for an anterior, sagittal plane spine deformity. However, further research is necessary to explore the impact of trunk alignment on standing and walking in patients with spinal deformities.

Publications

• Saha D, Gard S, Fatone S. (2008). The Effect of Trunk Flexion on Able-bodied Gait. Gait Posture. 27(4):652-660.
• Saha D, Gard S, and Fatone S. (2007). The Effect of Trunk Posture on Static Standing. Spine, 32(15):1605-1611.
• Saha, Devjani (2006). The Effect of Trunk Flexion on Standing and Walking, MS Thesis, Biomedical Engineering, Northwestern University.
• Saha D, Gard S, Fatone S, Ondra S. (2006). The Effect of Trunk Posture on Global Balance. 56th Annual Congress of Neurological Surgeons, Chicago, Illinois, October 7-12.
• Saha D, Gard S, Fatone S. (2006). Vertical Ground Reaction Force During Trunk-flexed Gait. American Society of Biomechanics, Blacksburg, Virginia, September 6-9.

• Co-Principal Investigators: Steven Gard, PhD, and Aruna Ganju, MD**
• Project Director: Pranitha Gottipati, PhD**
• Co-Investigators: Stefania Fatone, PhD, and Rebecca Stine, MS
• Funded by: Medtronic Sofamor-Danek, Inc.; National Institutes of Health (NIH); training grant National Institute on Disability and Rehabilitation Research (NIDRR)
• Status: Completed

** Department of Neurosurgery, Northwestern University

The role that spinal motion plays during ambulation is not clearly understood. Little in vivo regional spinal motion data exists in the literature with regard to walking and most gait analysis models disregard the upper body altogether, or regard it as a single rigid structure. This study aims to increase understanding of the contribution of spinal motion during ambulation by improving the way spinal motion is modeled and measured. By increasing knowledge of the relationship between spine motion and restriction, and its impact on the rest of the musculoskeletal system in locomotion, a broader understanding regarding the implications of disease and treatment will be gained.

Methods

A kinematic model was developed and validated for the study of regional spinal motion concurrently with conventional gait data. Application of this model allowed for development of a foundation of able-bodied spinal motion patterns and ranges of motion during gait. Able-bodied subjects were also studied with and without imposed spinal restriction to gait an understanding of how restricted spinal motion affects kinematics during walking.To fully appreciate the effects of spinal restriction and true surgical spinal fusion on gait, subjects with spine deformity were studied before and after surgery.

Results

This research provides preliminary evidence that the spine has a more substantial role in gait than previously demonstrated. Support for the intended effects of spinal restriction in both able-bodied and pathological subjects was found. Temporal-spatial gait parameters improved after long fusion surgeries in a pathological population. The stance phase knee flexion-extension kinematics significantly improved after fusion surgery. Increased accelerations at the head and cervical regions with spinal restriction (in both able-bodied and pathological subjects) provide evidence of the spine's role in shock attenuation during gait. Additionally, both static and dynamic pathological alignment after surgical spinal restriction more closely resembled able-bodied alignment.

The knowledge gained from this research contributes to a more comprehensive understanding of human walking, spinal motion and the effects of surgical fusions on spinal alignment.

Publications

• Gottipati P, Stine R, Ganju A, Fatone S (2018) The effect of positive sagittal spine balance and reconstruction surgery on standing balance. Gait and Posture. https://doi.org/10.1016/j.gaitpost.2018.03.024
• Gottipati P, Fatone S, Koski T, Sugrue P, Ganju A (2014) Crouch gait in persons with positive sagittal spine alignment resolves with surgery. Gait and Posture, 39:372-377. PMID: 24011797.
• Konz R, Fatone S, Stine R, Ganju A, Gard S, Ondra S (2006) A Kinematic Model to Assess Spinal Motion During Walking. Spine, 31(24):E898-E906. 17108818
• Konz R, Fatone S, Gard S (2006) The Effect of Restricted Spinal Motion on Gait in Able-bodied Persons. Journal of Rehabilitation Research & Development, 43(2):161-170. 16847783

Presentations

• Gottipati P, Fatone S (2016) Segmental Spinal Motion before and after Spinal Reconstruction Surgeries. NUPOC Biennial Symposium for the German-Speaking Travel Fellows of Initiative ’93, February 25, Chicago, IL.
• Gottipati P, Fatone S, Stine R, Ganju A (2013) Reduction in shock absorption capacity of the spine during gait after spinal reconstruction surgery (poster). Gait and Clinical Movement Analysis Society Annual Meeting, May 14-17, Cincinnati, OH.
• Gottipati P, Fatone S, Stine R, Ganju A (2013) Reduction in Shock Absorption Capacity of the Spine during Gait after Spinal Reconstruction Surgery (poster). 9th Annual Lewis Landsberg Research Day, Northwestern University, April 4, Chicago, IL.
• Gottipati P, Fatone S, Stine R, Ganju A (2013) Reduction in Shock Absorption Capacity of the Spine during Gait after Spinal Reconstruction Surgery. Northwestern University Postdoctoral Forum (NUPF), September 12, Evanston, IL.
• Gottipati P, Fatone S, Ganju A (2012) Effect of fusion surgery on static and dynamic sagittal spinal alignment (poster). 47th Scoliosis Research Society, September 5-8, Chicago, IL.
• Gottipati P, Fatone S, Stine R, Ganju A. (2011) Effect of Multi Segmental Spine Fusion Surgeries on Spine and Gait Kinematics (poster). Gait and Clinical Movement Analysis Society, April 26-29, Bethesda MD.
• Gottipati P, Fatone S, Stine R, Ganju A. (2011) Effect of Multi Segmental Spine Fusion Surgeries on Spine and Gait Kinematics (poster). The 7th Annual Lewis Landsberg Research Day, Northwestern University, April 7, Chicago, IL.
• Konz, Regina Jane (2007), "The Role of the Spine in Human Walking: Studies of Able-bodied Persons and Individuals with Spine Pathologies," PhD Dissertation, Biomedical Engineering, Northwestern University.
• Konz R, Fatone S, Gard S, Ganju A and Ondra S. The Effects of Spinal Restriction on Walking: II. Lower Limb Data. Scoliosis Research Society. The 40th Annual Meeting, Miami, FL, October 27-30, 2005.
• Konz R, Ganju A, Fatone S, Ondra S and Gard S. Non-invasive Measurement of Static and Dynamic Alignment. Congress of Neurological Surgeons, Boston, MA, October 8-13, 2005.
• Konz R, Ganju A, Fatone S, Ondra S and Gard S. The Effects of Spinal Restriction on Walking: I. Regional Spinal Kinematics. The12th International Meeting on Advanced Spine Techniques, Banff, Canada, July 7-9, 2005.
• Konz R, Fatone S, Gard S, Ganju A and Ondra S. The Effects of Spinal Restriction on Walking: II. Lower Limb Data. The12th International Meeting on Advanced Spine Techniques, Banff, Canada, July 7-9, 2005.
• Konz R, Fatone S, Gard S. The Effect of a Thoraco-Lumbo-Sacral-Orthosis on Gait. The 31st Academy Annual Meeting & Scientific Symposium, Orlando, FL, March 16-19, 2005.
• Konz R, Fatone S, Gard S. The Effect of a Thoraco-Lumbo-Sacral-Orthosis on Gait. The 11th World Congress of the International Society for Prosthetics & Orthotics, Hong Kong, August 1-6, 2004.
• Konz R, Ganju A, Fatone S, Gard S and Ondra S. Non-invasive Measurement of Static and Dynamic Alignment: Preliminary Data. The 39th Annual Meeting of the Scoliosis Research Society, Buenos Aires, Argentina, September 6-9, 2004.
• Konz R, Ganju A, Fatone S, Gard S, Ondra S. Non-invasive Measurement of Static and Dynamic Alignment: Preliminary Data. The 11th International Meeting on Advanced Spine Techniques, July 1-3, 2004 Fairmont Southampton, Bermuda.
• Konz R, Fatone S, Gard S. The Effect of Thoraco-Lumbo-Sacral Orthoses on Gait. Gait and Clinical Movement Analysis Society. The 9th Annual Meeting, Lexington, KY, April 21-24, 2004.
• Konz R, Stine R, Ganju A, Fatone S, Jorge A, Gard S, Childress D, Ondra S. Development of An Advanced Biomechanical Spine Model to Assess the Effect of Surgical Stabilization and Alignment on Gait. Congress of Neurological Surgeons 53rd Annual Meeting, Denver, CO, October 18-23, 2003.
• Konz R, Stine R, Fatone S, Ganju A, Jorge A, Gard S, Childress D, Ondra S. Development of an Advanced Biomechanical Spine Model to Assess the Effect of Surgical Stabilization and Alignment on Gait. The 10th International Meeting on Advanced Spine Techniques, Rome, Italy, July 10-12, 2003.
• Konz R, Stine R, Fatone S, Gard S, Childress D, Ganju S, Ondra S. An Advanced Biomechanical Model to Assess How Spinal Motion Contributes to Gait: Preliminary Data. Gait and Clinical Movement Analysis Society. The 8th Annual Meeting, Wilmington, DE, May 7-10, 2003.