Spino-pelvic sagittal parameters in patients with degenerative thoracolumbar kyphosis combined with lumbar stenosis syndrome

Objective: The patients diagnozed degenerative thoracolumbar kyphosis (DTLK) with lumbar spinal syndrome (LSS) were enrolled, to identify the significance of spino-pelvic parameters in this group. Methods: An overall 138 (M/F=53/85) patients were enrolled with a mean follow-up of 24.6±11.1 (m). All cases were performed short-segment posterior fusion on LSS region. Radiological parameters were TLK, LL, PI, PT and SVA obtained on the X-ray. Quality of life (QOL) were evaluated by the visual analogue scale (VAS) and the Oswestry disability index (ODI). Accorrding to age-related formula by Lafage, various thresholds on PI-LL, PT and SVA were determined, ensuing three pairs of normal and abnormal groups were respectively divided into based on these parameters. Results: Both VAS and ODI statistically improved (P <0.001). At the endpoint, TLK decreased by a mean of 8.2±8.8° and cases got TLK-correction occupied 40.4%. The whole balance status (normal SVA) was improved compared to baseline (P=0.006), so was the ratio of matched PI-LL (P=0.002), but the ratio of normal PT and larger PT was of no significance (P=0.794). The final balance status was irrelevant to QOL whatever balance status at baseline. However, ODI in PI-LL matched group or in normal PT group were respectively less than that of abnormal groups (P=0.022 and P=0.019). Conclusions: The mean TLK decreased even a short-segment fusion purely performed on LSS. QOL was related to PI-LL and PT, but not to SVA in DTLK patients.