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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.
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Objective To compare the minimum 5?year follow?up outcomes of surgical management by posterior only ap?proaches, anterior only approaches and combined posterior and anterior approaches for thoracic tuberculosis in adults, and evalu?ate the mid term follow?up results of posterior only approaches. Methods All of 184 patients with monosegment thoracic tubercu?losis between January 2003 and November 2010 were studied retrospectively. Among these patients, 62 cases were treated with posterior debridement combine with interbody fusion (PO group), 65 cases were treated by posterior instrumentation, anterior de?bridement and bone graft in one or two?stage procedures (AP Group ), and 57 cases were treated by anterior only approach (AO Group). The operation time, blood loss, Visual Analogue Scale, complications, recovery of neurological function, kyphosis angle, correction rate and loss angle were respectively compared between each group. Results Comparison of postoperative curative ef?fects showed:mean operation time and blood loss:PO group (260.05±30.75 min,735.95±161.43 ml) was better than AP group (411.65 ± 55.61 min, 1178.65 ± 184.50 ml)and AO group (343.65 ± 24.74 min, 965.35 ± 122.59 ml);corrective angle and correction rate:PO group (6.78°±1.13°, 72.48%±12.97%) and AP group (6.97°±1.05°, 73.10%±11.42%) were better than AO group (13.98°± 1.73°, 44.95%±16.84%);bed time:PO group and AO group were shorter than AP group. Mid term follow?up outcomes showed:ky?phosis angle and loss angle:PO group (8.56°±1.09°, 1.89°±1.41°) and AP group (8.55°±1.65°, 1.63°±1.11°) were better than AO group (16.39°±1.59°, 2.80°±1.29°);bone fusion time, VAS and recovery of neurological function:there were no statistically differ?ence in all groups. Conclusion The mid term follow?up outcomes of posterior debridement combined with interbody fusion is sat?isfied in the management of monosegment thoracic tuberculosis. It is a safe and effective method.