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Clinical Gait Analysis on a Patient Undergoing Surgical Correction of Kyphosis from Severe Ankylosing Spondylitis

Ram Haddas, PhD,1 Theodore Belanger, MD2

1Texas Back Institute Research Foundation, Plano, TX, USA, 2Texas Back Institute, Rockwall, TX, USA



Ankylosing spondylitis (AS) is a chronic inflammatory disease primarily affecting the axial skeleton, including the sacroiliac joints, costovertebral joints, and the spine. Patients with AS found to have an alter gait pattern. The purpose of this study was to investigate biomechanical alterations in gait after surgical correction in a patient with severe kyphosis from AS.


A case report in controlled laboratory study, a pretest-posttest design. A 20 year-old male presented with severe sagittal imbalance and inability to stand erect due to AS. He presented with thoracic kyphosis of 70°, lumbar kyphosis of 25°, and pelvic incidence of 43°. The patient had a complex spinal reconstruction with 84° of sagittal correction, normalizing his sagittal alignment. Gait analysis was performed the day before surgery and one month post surgery, including three-dimensional kinematics, ground reaction forces, and electromyography outcomes.


Normalization of spinal alignment minimally increased walking speed and cadence. Lower extremity ranges of motion angles increased, but were not symmetrical even one month post surgery. Postoperatively, trunk flexion, neck extension and head orientation angles decreased compared with preoperative values, but was not symmetrical even one month post surgery. The trunk muscles were activated earlier in the post surgery condition compared to the pre surgery condition while lower extremity muscles presented later muscle activation. 


Surgical correction of spinal alignment improved spine function and efficiency. Changes in gait abnormality parameters observed imply that the patient used less energy to ambulate after surgery than before surgery. Although pre-surgery data showed compensation in the spine kinematics, post-surgery data supported significant changes in the spine and the lower extremity values. 

Clinical Relevance

Formal gait and motion analysis can provide a method to assess the impact of severe spinal deformity on function and changes after treatment.

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Ankylosing Spondylitis, Gait Analysis, Electromyography, Three-Dimensional Kinematics, Laminectomy, Osteotomy, Spinal Fusion.
Volume 11 Issue 3
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