Effect Of Topping-off Surgery On Lower Lumbar Sagittal Balance

Objective:By observe the imageology of Topping-off surgery (PLIF united with Wallis system) and PLIF in the treatment of lumbar degenerative disease,the aim of this study was to evaluate the influence of Topping-off surgery on sagittal balance.Methods:The retrospective study included 20 cases of PLIF united with Wallis system(Topping-off surgery) in our hospital from Jan 2010 to Mar 2012 with the intact follow-up data. They included 9 males and 11 females, with an average of 50.6 years ranging in age from 35 to 65 years.13 cases were L5-S1 fusion, L4-5 Wallis dynamic interspinous stabilization device implantation.7 cases were L4-5 fusion, L3-4 Wallis implantation. In the same time the retrospective study included 22 cases of PLIF.The patients all had low back pain, low limb neurological symptoms or neurogenic intermittent claudication and had been confirmed the responsible segment and diagnosis by X ray plain, CT and MRI. Observe and compare the two groups of patients with lower lumbar sagittal parameters, including lumbar lordosis, pelvic indence, sacral slope, pelvic tilt, segmentary lumbar lordosis and disc height.Results:The average follow-up time was 35.8 months. The index of assessing sagittal balance is lumbar lordosis, sacral tilt, pelvic indence, pelvic tilt, segmentary lumbar lordosis and disc height. In the Topping-off group lumbar lordosis decreased from 35.23°±8.53°preoperatively to34.74°±10.23°after 6 months(P>0.05), and to 39.19°±4.51°after 3 years(P>0.05).At the follow up of 6 months and 3 years, lumbar lordosis showed no statistical difference compared to that of preoperatively, but it showed a tendency of decrease after 6 months and a tendency of increase after 3 years. In the PLIF group lumbar lordosis increased from 34.04°±5.75°preoperatively to39.89°±7.45°after 6 months(P<0.05), and to 40.89°±7.45°after 3 years(P<0.05). In the Topping-off group sacral tilt increased from 28.58°±6.78°preoperatively to 30.23°±8.53°after 6 months(P>0.05), and to 31.59°±1.57°after 3 years(P<0.05). Sacral tilt showed a tendency of increase after 6 months, but showed significant difference at the final follow up. In the PLIF group sacral tilt increased from 26.23°±6.34°preoperatively to31.95°±9.47°after 6 months(P<0.05), and to 30.23°±8.53°after 3 years(P<0.05). In the Topping-off group pelvic tilt decreased from 22.68°±4.21°preoperatively to 18.95°±7.06°after 6 months(P<0.05), and to 19.27°±5.12°after 3 years(P<0.05). In the PLIF group sacral tilt increased from 21.39°±7.8°preoperatively tol6.89°±6.45°after 6 months(P<0.05), and to 17.53°±8.41°after 3 years(P<0.05). In the Topping-off group pelvic tilt decreased from 22.68°±4.21°preoperatively to 18.95°±7.06°after 6 months(P<0.05), and to 19.27°±5.12°after 3 years(P<0.05). In the PLIF group sacral tilt increased from 21.39°±7.8°preoperatively to16.89°±6.45°after 6 months(P<0.05), and to 17.53°±8.41°after 3 years(P<0.05). In the Topping-off group disc height increased from 0.36±0.1 preoperatively to 0.56±0.12 after 6 months(P<0.05), and to 0.52±0.32 after 3 years(P<0.05). In the PLIF group sacral tilt increased from 0.39±0.08 preoperatively to0.36±0.05 after 6 months(P<0.05), and to 0.32±0.1 after 3 years(P<0.05).Conclusions:1. There is some protevtive effect on sagittal balance of Topping-off surgery and PLIF in the treatment of lumbar degenerative disease. But the long-term effect need next retrospective study.2. Compared with PLIF, Topping-off surgery has no obvious advantages on the sagittal balance. However on the protect of the adjacent segment Topping-off surgery may have the advantage.