Is the T9, T11, or L1 Proximal Level the More Stable Following Lumbar/Lumbosacral Fusions from the Thoracolumbar Junction to L5-S1?

Methods: A radiographic and clinical outcome assessment of 90 adult lumbar deformity patients (average age 55.0 years) who underwent long posterior spinal instrumentation and fusion from the thoracolumbar spine to the L5- S1 with a minimum 2-year follow up (2-15.8 year follow-up) was compared according to T9/T10 (Group1, n=25), T11/T12 (Group 2, n=35), and L1/L2 (Group 3, n=30) proximal fusion levels. Proximal junctional kyphosis (PJK) was defined by proximal junction sagittal Cobb angle between the lower end plate of the uppermost instrumented vertebra and the upper end plate of 2 supradjacent vertebra ³ +10 degrees and at least 10 degrees greater than the preoperative measurement at the ultimate follow-up.

Results: Three group demonstrated similar follow-up (p=0.41), different age at surgery (Group1 48.2 years vs. Group 2 55.3 years vs. Group 3 60.9 years, p<0 .001), nonsignificant differences in the postoperative thoracic sagittal Cobb angle progression (p="0.65)," proximal junctional change and vertical axis at ultimate follow-up. The prevalence of PJK demonstrated no significant relation among 3 groups preoperative imbalance (C7 plumb> 8cm vs <8CM , p="0.39)," and older age at surgery (>55 years vs. 55 years or below, p=0.32). Proximal junctional angle (PJA) change demonstrated positive correlation with ultimate PJA (R=0.531, p<0 .0001), ultimate thoracic kyphosis progression (R="-0.330," p<0.0001), and negative correlation with preoperative PJA p="0.002)." The SRS outcome scores did not demonstrate significant differences (p="0.31)." (See Table).

Conclusion: Three different proximal fusion levels did not demonstrate significant radiographic and clinical outcomes differences postoperatively. Therefore the more distal proximal fusion level at a neutral and stable vertebra is satisfactory. Sagittal balance after lumbar/lumbosacral fusion Table. Comparison among three different proximal stops.

Hibbs Award Nominee for Best Clinical Paper