Three-Dimensional CT Based Specimen-Specific Kinematic Model for Ex Vivo Assessment of Lumbar Neuroforaminal Space Journal Article

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Authors: Havey, R. M.; Goodsitt, J.; Khayatzadeh, S; Muriuki, M.; Potluri, T.; Voronov, L. I.; Lomasney, L. M.; Patwardhan, A. G.
Article Title: Three-Dimensional CT Based Specimen-Specific Kinematic Model for Ex Vivo Assessment of Lumbar Neuroforaminal Space
Abstract: STUDY DESIGN: Cadaveric study to accurately measure lumbar neuroforaminal area and height throughout the flexion-extension range of motion (ROM). OBJECTIVES: Create a new CT-based specimen-specific model technique to provide insight on the effects of kinematics on lumbar neuroforamen morphology during flexion-extension (FE) ROM. SUMMARY OF BACKGROUND DATA: Nerve root compression is a key factor in symptomatic progression of degenerative disc disease (DDD) since these changes directly affect neuroforaminal area. Traditional techniques to evaluate the neuroforamen suffer from poor accuracy, have inherent limitations and fail to provide data throughout the ROM. METHODS: Six cadaveric specimens (L1-Sacrum) were instrumented with radiopaque spheres and CT scanned. 3-D reconstructions were made of each vertebra and the sphere locations determined. During kinematic testing the spheres were located in relation to optoelectronic targets attached to each vertebra. The result was a 3-D representation of the specimen's CT reconstruction moving in response to experimental data. Bony contours of the L2-L3 and L4-L5 neuroforamen were digitized producing continuous neuroforaminal area and height data throughout the ROM. RESULTS: Neuroforaminal area and height linearly increased in flexion and decreased in extension. There was significant correlation between FE motion and percent change in area (L2-L3: 3.1%/degree, R = 0.94, L4-L5: 2.5%/degree, R = 0.90) and neuroforaminal height (L2-L3: 2.1%/ degree, R = 0.95, L4-L5: 1.6%/degree, R = 0.93). Regression analysis showed that the ratio between neuroforaminal height and area is at least 1:1.5 such that a 100% increase in height is associated with an area increase over 150%. CONCLUSION: This is the first study to measure lumbar neuofoarminal area and height throughout flexion-extension ROM. The CT-based specimen-specific model technique can accurately evaluate the effect of kinematics on morphological features of the spine. The demonstrated increase in neuroforaminal dimension in flexion is consistent with treatment modalities used in clinical therapies to relieve radicular symptoms.
Journal Title: Spine
Volume: 40
Issue: 14
ISSN: 1528-1159; 0362-2436
Publisher: Unknown  
Date Published: 2015
Start Page: E814
End Page: E122
Language: ENG
DOI/URL:

10.1097/BRS.0000000000000959
Notes: LR: 20150507; JID: 7610646; aheadofprint