Artikel
Spino-pelvic alignment after short segment transforaminal lumbar interbody fusion (TLIF) – Is correction possible and worthwhile?
Suche in Medline nach
Autoren
Veröffentlicht: | 22. Oktober 2019 |
---|
Gliederung
Text
Objectives: Sagittal alignment is governed by radiological parameters such as pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and lumbar lordosis (LL). Matching LL and PI, and a low Global Alignment and Proportion (GAP) Score influence both clinical outcome and the risk of revision in long fusion. The influence of short transforaminal lumbar interbody fusion (TLIF) on the sagittal profile is equivocal. This retrospective study aimed to evaluate the magnitude of the change in segmental and regional lordosis in short segment TLIF (1-3 segments), and its effect on spino-pelvic alignment and prospectively evaluated clinical outcome.
Methods: From our local spine outcomes database (linked to the Spine Tango Registry), we identified 196 patients with no coronal deformity >20° and no previous spine surgery who had undergone TLIF (1-3 segments) for degenerative spinal disorders in 2012. The following were measured on standing lumbar spine radiographs taken before and six weeks after surgery: PI, PT, SS, LL, L4-S1 lordosis, fused segments lordosis (FSL), and remaining unfused segments lordosis (RSL). Based on these measurements, spino-pelvic alignment (PI-LL) and L-GAP-Score were assessed, and patients were categorized as PI-LL balanced, unbalanced, or uncompensated and L-GAP proportioned, moderately disproportioned or severely disproportioned. The Core Outcome Measures Index (COMI) was used to assess patient-rated outcome pre-, and 2- and 5- years post-operatively.
Results: TLIF was performed in 1 segment in 140, 2 segments in 50 and 3 segments in 6 patients. 106 patients had degenerative spondylolisthesis, 32 isthmic spondylolisthesis, and 58 osteochondrosis. The radiological measurements (PT, SS, LL, L4-S1) showed no significant differences, pre- to postoperatively. FSL was increased from 21.9±10.4° pre- to 23.4±9.2° postoperatively (1.3±4.5° per fused segment) (both p<.01); however, the proportion of patients in the PI-LL and L-GAP-Score categories showed no significant differences. There was a low but significant correlation between the increase in FSL and the decrease in RSL (R=-0.285, p<.01). The COMI improved significantly from 7.2±1.7 at baseline to 2.5±2.5 and 2.8±2.5 at 2- and 5-years' postoperatively, respectively (each p< .01). Patients were more likely to achieve the minimal clinically important change (MCIC) in COMI score at 5 years' postoperatively with FSL >3 (87.9%) than with FSL<3° (72.6%) (p=.03).
Conclusion: Short segment TLIF can increase lordosis within fused segments, and reduce compensatory mechanisms in the unfused lumbar spine. A good clinical outcome is achieved for the majority of patients at five-years' follow-up independent of spino-pelvic alignment. An increase of lordosis in the fused segments of more than 3 degrees appears to be associated with better clinical outcome.