Paraspinal muscle vasculature contributes to posterolateral spinal fusion.
METHODS
Study of posterolateral fusions in a rabbit model.


OBJECTIVE
To characterize the contribution of paraspinal musculature to the healing of posterolateral spinal fusions in a rabbit model.


BACKGROUND
Previous studies have demonstrated that successful spinal arthrodesis requires vascular ingrowth from adjacent decorticated bone. In other areas of the body, such as the tibia, vascular ingrowth from the surrounding musculature has also been shown to be important. The role of the surrounding paraspinal musculature in spinal fusions has yet to be assessed.


METHODS
Twenty-five New Zealand white rabbits underwent posterolateral spinal fusion. One side of the animals was treated with autograft alone and served as the control group. On the contralateral side, the autograft was contained within porous or nonporous barrier sheets. Following euthanization, high-resolution radiographs, CT scans, and histologic analyses were performed to assess fusion and characterize vascular ingrowth.


RESULTS
Using histologic evaluation, the fusion rate in the porous group was 90%, in the nonporous group 40%, and in the control group 55%. Vascular ingrowth was evident from the muscle through the porous sheet into the fusion mass.


CONCLUSIONS
These results support our hypothesis that the paraspinal musculature provides important vascular ingrowth into the fusion site. Use of a porous barrier sheet appears to improve fusion by preventing muscle interposition while allowing vascular ingrowth from surrounding muscle.
Bawa
Maneesh
M
Department of Orthopaedic Surgery, University of California, San Diego, San Diego, CA 92161, USA.
Schimizzi
Aimee L
AL
Leek
Bryan
B
Bono
Christopher M
CM
Massie
Jennifer B
JB
Macias
Brandon
B
Chung
Christine B
CB
Hargens
Alan R
AR
Garfin
Steven R
SR
Kim
Choll W
CW
D000818:Animals; D008159:Lumbar Vertebrae / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000601:surgery*; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000000981:diagnostic imaging; D011817:Rabbits; D011859:Radiography; D013123:Spinal Fusion / Q000379:methods*