Ji-chen Huang, Wei-yi Diao, Bang-ping Qian, Bin Wang, Yang Yu, Mu Qiao, Yong Qiu


December 2020, Volume 29, Issue 12, pp 3028 - 3037 Original Article Read Full Article 10.1007/s00586-020-06538-w

First Online: 20 July 2020

Purpose

To compare the surgical outcomes between ankylosing spondylitis (AS)-related thoracolumbar kyphosis patients with the lowest instrumented vertebra (LIV) at S1 or above following one-level pedicle subtraction osteotomy (PSO).

Methods

One hundred and two AS patients undergoing one-level PSO with a minimum of 2-year follow-up were included. Twenty-two patients were in group S1 (LIV at S1), and eighty were in group non-S1 (LIV above S1). Radiographic parameters including lumbar lordosis (LL), sacral slope (SS), pelvic incidence (PI), and sagittal vertical axis (SVA) were measured. Oswestry Disability Index (ODI) and visual analog scale (VAS) were applied for clinical assessment.

Results

In both S1 and non-S1 groups, the radiographic parameters and clinical outcomes were significantly improved after surgery (P   0.05), as well as the improvement in ODI and VAS (P  > 0.05). The incidence of overall complications and each type of complication including the implant failure was similar between group S1 and non-S1 (P  > 0.05).

Conclusion

Selecting S1 as the LIV without pelvic fixation following one-level PSO in thoracolumbar kyphosis caused by AS could achieve satisfactory surgical outcomes and might not increase the complications. Patients with relatively severe sagittal imbalance, loss of LL, PI–LL mismatch, and small SS might be the potential candidates for distal fusion to S1 following one-level PSO.


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