Lumbosacral-levelization during surgery reduce the risk of post-operative coronal imbalance in degenerative lumbar scoliosis after long spinal fusion

Abstract

Objective To evaluate the postoperative coronal balance and clinical outcomes of transforaminal lumbar interbody fusion (TLIF) at convex side utilized in adult degenerative lumbar scoliosis (DLS) patients with coronal imbalance type C (C7PL shifted to the convex side for more than 3 cm). Methods All of 27 patients (2 males and 25 females) receiving posterior long spinal segment fusion surgery (5 or more segments involved) from June 2006 to June 2015 were retrospectively reviewed. The average age of the cohort was (62.11±8.22) years, (range, 50-76 years). 11 patients underwent to a transforaminal lumbar inter-body fusion (TLIF) at convex side of fractional curve procedure, while 16 had only long fusion. The coronal parameters including Cobb angle and distance between C7 plumb line and center sacral vertical line (C7PL-CSVL), as well as oblique angle of L4, L5, S1 and fusion level of L4, 5, L5S1 were measured preoperatively, postoperatively and last follow up. The Short Form-36 Health Survey (SF-36), Oswestry dability index(ODI), visual analogue scale(VAS) were assessed at pre-operation, post-operation and follow up. Clinical and radiographic parameters were compared between the two groups. Results The average follow up period was (51±11) months(24-120 months). The preoperative Cobb angles were 41.9°±10.7°. Two groups of patients had similar preoperative and postoperative lumbar curve correction; there was no significant differences in SVA (sagittal vertical axis) between two groups. Preoperative L 4,5 or L 5S1 tilt existed in all two groups of patients. After surgery, there were significant differences in correction of L 5S1 tilt (LIV=L5, 2.1 ° and 8.1 °±3.7 °, LIV=S1, 3.8 °±2.4 ° and 8.1 °±2.9 °, LIV=S2, 3.1 °±2.8 ° and 8.7 °±3.9 °) in DLS patients with TLIF, and patients in TLIF group had better preservation of correction than those in no TLIF group at final follow-up. Coronal balance distance (coronal balance distance, CBD) of TLIF group at final follow-up was significantly less than no TLIF group (1.8 ± 0.9 cm and 2.5 ±1.5 cm). Patients in TLIF group had a significantly higher fusion rate (100%, 11/11 and 93.75%, 15/16) and less postoperative complications than those from no TLIF group. Conclusion Performing TLIF at convex side could even the lumbar-sacral junction, promote the fusion process, and reduce the risk of postoperative coronal imbalance in preoperative coronal imbalance type C DLS patients. Key words: Lumbar vertebrae; Scoliosis; Adult; Spinal fusion