Clinical effect of surgical reduction and posterior lumbar interbody fusion in treating grade Ⅱ-Ⅲ L5 isthmic spondylolisthesis with completely collapsed disc space

English Keywords:Lumbar spondylolisthesis  Sondylolysis  Collapsed disc space  Reduction  Interbody fusion  Sagittal parameters

English Abstract:

  【Abstract】 Objectives: To observe the effect of surgical reduction and posterior lumbar interbody fusion(PLIF) in treating grade Ⅱ-Ⅲ L5 isthmic spondylolisthesis(IS) with completely collapsed disc space. Methods: The imaging and clinical data of 49 patients with grade Ⅱ-Ⅲ L5 IS with completely collapsed disc space treated with surgical reduction and PLIF were reviewed. There were 22 males and 27 females, aged 58.0±9.8 years old, with a follow-up period of 31.2±6.9 months. The operational complications were recorded, and low back and leg pain visual analog scale(VAS) score, Oswestry disability index(ODI) preoperatively, 1 month and 2 years postoperatively were recorded and compared. The radiographic outcomes, including slippage percentage, pelvic incidence(PI), pelvic tilt(PT), sacral slope(SS), lumbar lordosis(LL), L1-L5 lordosis(L1-5L) and L5-S1 lordosis(L5-S1 L) were measured on standing lateral spinal X-rays preoperatively, 1 month and 2 years postoperatively. Before operation and at 2 years after operation the balance conditions of pelvis were evaluated according to Hresko line Y=（0.844835×X）+25.021. With SS as the Y-axis and PT as the X-axis, each case corresponded to a scatter point, and 49 cases constituted the scatter plot. When the scatter point was above the Hresko line, the corresponding case had a balanced pelvis, and when it was below the Hresko line, the corresponding case had an unbalanced pelvis. Results: The operation went smoothly in all the patients. Four patients experienced temporary leg pain after surgery, which improved significantly after symptomatic treatment. One patient experienced sacral screw fracture 18 months after surgery, and CT scan showed bone fusion in the L5/S1 segment. And the internal fixation was removed, and there was no significant low back or leg pain observed during the 3-month follow-up after removal of internal fixation. The VAS score and ODI at 1 month and 2 years after operation reduced significantly compared with those values before operation(P<0.05). No significant difference was observed between the preoperative and postoperative PIs(P>0.05). SS increased from 41.6°±4.1° before surgery to 43.7°±4.5° 2 years after surgery(P<0.05), LL increased from 45.1°±9.8° before surgery to 52.2°±7.8° 2 years after surgery(P<0.05), and L5-S1 L increased from 8.7°±2.6° before surgery to 21.8°±4.3° 2 years after surgery(P<0.05). SP decreased from 54.3°±8.4° preoperatively to 9.4°±3.1° 2 years postoperatively(P<0.05), PT decreased from 18.3°±3.7° preoperatively to 16.7°±4.0° 2 years postoperatively(P<0.05); L1-5 L decreased from 36.5°±8.3° before surgery to 31.4°±6.7° 2 years after surgery(P<0.05). There were 31 cases with balanced pelvis and 18 cases with imbalanced pelvis before operation, while there were 42 cases with balanced pelvis and 7 cases with imbalanced pelvis after operation, and the difference was statistically significant(P<0.05). Conclusions: In treating patients of grade Ⅱ-Ⅲ L5 IS with collapsed disc space, surgical reduction and PLIF can improve the imbalance conditions of pelvis, which can reduce spino-pelvic compensation and achieve satisfactory clinical results.