Influence of transforaminal lumbar interbody fusion procedures on spinal and pelvic parameters of sagittal balance

Abstract

Introduction: Restitution of sagittal balance is important after lumbar fusion, because it improves fusion rate and may reduce the rate of adjacent segment disease. The purpose of the present study was to describe the impact of transforaminal lumbar interbody fusion (TLIF) procedures on pelvic and spinal parameters and sagittal balance.

Materials and methods: Forty-five patients who had single-level TLIF were included in this study. Pelvic and spinal radiological parameters of sagittal balance were measured preoperatively, postoperatively and at latest follow-up.

Results: Age at surgery averaged 58.4 (±9.6) years. Mean follow-up was 35.1 months (±4.1). Twenty-nine percent of the patients exhibited anterior imbalance preoperatively, with high pelvic tilt (17.6° ± 7.9°). Of the 32 (71%) patients well balanced before the procedure, 22 (70%) had a large pelvic tilt (>20°), due to retroversion of the pelvis as an adaptive response to the loss of lordosis. Three dural tears (7%) were reported intraoperatively. Interbody cages were more posterior than intended in 27% of the cases. Disc height and lumbar lordosis at fusion level significantly increased postoperatively (p < 0.05 and p < 0.001). Pelvic tilt was significantly reduced (p < 0.01) postoperatively, whereas the global sagittal balance was not significantly modified (p = 0.07).

Conclusion: Single-level circumferential fusion helps patients reducing their pelvic compensation, but the amount of correction does not allow for complete correction of sagittal imbalance.

Figures

Fig. 1

TLIF circumferential arthrodesis

Fig. 2

Disc height measurement method. DH = ((AB + CD)/2)/H

Fig. 3

Lateral radiograph of a patient with a spinal anterior imbalance (SVA = 82 mm)

Fig. 4

Lateral standing radiograph of a 72 year-old patient, sagittally balanced (SVA = 18 mm), but with increased pelvic tilt (PT = 30°), traducing a compensating pelvic retroversion. Parameters were measured with Optispine (Optimage, Lyon, France) [12]

Fig. 5

TLIF cage positioned in the middle third of the intervertebral space