Predictive value of vertebral trabecular and endplate Hounsfield Units on cage subsidence followed posterior lumbar interbody fusion / 中华骨科杂志

ABSTRACT

Objective:To explore the predictive value of vertebral trabecular and endplate HU values on cage subsidence after posterior lumbar interbody fusion (PLIF), hope to provide reference for surgical planning.Methods:All of 72 patients with lumbar disc herniation that underwent PLIF were retrospectively reviewed, who were divided into two groups according to the occurrence of cage subsidence at one-year follow up. Cage subsidence was defined as more than 4 mm subsidence into the vertebrae valuated by CT at one-year follow up. There were 18 patients enrolled into Subsidence group and 54 patients enrolled into N-Subsidence group. The lumbar lordosis, segmental lordosis, intervertebral height, off-bed time, hospital stay, complications, the trabecular and endplate HU values of upper instrumented vertebrae (UIV) and lower instrumented vertebrae (LIV) were compared between the two groups. ROC was used to explore the thresholds of HU values.Results:There were 14 patients presented cage subsidence into the L4, 4 patients presented cage subsidence into the L5. There was no significant difference in lumbar lordosis, segmental lordosis, intervertebral height, off-bed time, hospital stay, or complications between the two groups. Both UIV and LIV trabecular and endplate showed a lower HU value in Subsidence group than those in N-Subsidence group. The most appropriate thresholds of HU value were 146, 172, 307, 254 for trabecular of UIV, trabecular of LIV, lower endplate of UIV, and upper endplate of LIV, respectively.Conclusion:Vertebral trabecular and endplate HU values could effectively predict the cage subsidence after PLIF, patients should be completely informed the risk of cage subsidence and larger cage should be recommended if they presented HU values under the certain threshold.