Background:

Only a few studies have addressed the clinical outcomes of the revision surgery for ASD. The purpose of this study is to elucidate the clinical outcomes of second (repeat) posterior lumbar interbody fusion (PLIF) by focusing on the relationship between clinical outcomes and spinopelvic parameters, and predisposing factors requiring subsequent corrective long fusion after repeat PLIF.

Methods:

We analyzed the data of 47 patients aged 40+ years who underwent repeat PLIF after single-segment PLIF due to ASD. The correlation between clinical outcomes and radiographic parameters was investigated. Patient demographics and radiographic parameters were compared between patients with and without subsequent corrective long fusion.

Results:

JOA score at the final follow-up was 13.4 points, and the recovery rate was 37.2%. All sagittal parameters except pelvic tilt and C7-central sacral vertical line at the final follow-up showed weak to moderate (|r|=0.30-0.56) correlation with clinical scores. Finally, 11% of the patients required subsequent long corrective fusion. Pelvic incidence-lumbar lordosis (PI-LL) mismatch (cutoff value of 27.5°) and thoracic kyphosis (cutoff value of 12.5°) before repeat PLIF were identified as predisposing factors for subsequent long corrective fusion.

Conclusions:

The clinical outcomes of repeat PLIF were inferior to those of primary PLIF. Once the PI-LL mismatch occurs after initial PLIF, it will be difficult to resolve the PI-LL mismatch during the second PLIF. To stop the chain of reoperations in patients whose pre-operative PI-LL exceeds 27.5° before repeat PLIF, corrective long fusion may be a surgical option to consider.