Planning Spinal Fusion? Consider Each Level’s Load

Researchers in Germany looked at spinal loads before and after spinal fusion. Their finding? It’s important to examine each level individually to avoid sagittal imbalance. The study, “Regarding loads after spinal fusion, every level should be seen separately: a musculoskeletal analysis,” appears in the January 19, 2018 edition of the European Spine Journal. 

Achim Benditz, PD, Dr. med. habil., with the Department of Orthopedics, University Medical Center Regensburg, Asklepios Klinikum Bad Abbach in Germany said, “The more spinal fusions are done, the more important the sagittal balance gets. To know more about loads in single levels in theory the better sagittal balance can be restored during surgery. Not many studies have been made with real patient data after spinal fusion. Therefore, this collective is an important contribution to spinal surgery planning.”

The authors wrote, “The joint reaction forces of 52 patients were analyzed in proximo-distal and antero-posterior [AP] direction from the levels T12–L1 to L5–S1 using musculoskeletal simulations. In 104 simulations, pre-surgical forces were equal to post-surgical. The levels L4–L5 and T12–L1, however, showed increased spinal forces compression forces with higher sagittal displacement. Improved restoration of sagittal balance was accompanied by lower spinal load. AP shear stress, interestingly decreased with sagittal imbalance.”

“The most important findings are that every level must been seen separately and the distribution of spinal loads depends on every level. It is important to plan all spinal fusions regarding sagittal balance and especially spinal loads of every single level.”