Unilateral Or Bilateral Lumbar Fusion Internal Fixation For Patients Of Different Ages Observational Study Of Adjacent Segment Degeneration

Objective:To investigate adjacent segment degeneration(ASD)after posterior lumbar interbody fusion using either unilateral or bilateral pedicle screw instrumentation for patients of different ages with L4-5 intervertebral disc herniation. Methods:The retrospective analysis was performed on the clinical data in 120 cases of posterior lunbar interbody fusion using either unilateral or bilateral pedicle screw fixation with single L4-5 intervertebral disc herniation. There were divided into unilateral and bilateral groups: unilateral group(A1 group ranged in age from 18 to 62 years,and A2 group ranged in age from 40 to 60 years) and bilateral group(B1 group ranged in age from 18 to 40 years,and B2 group ranged in age from 40 to 60 years). All patients were followed minimum 5 years postoperatively.Lumbar spine postoperative adjacent segment degeneration compared between the different ages. Results:In total, 120 patients were available for at least 5 years of radiologic and clinical follow-up. In the unilateral group(58 patients), A1 group were 31 patients, A2 were 27 patients, In the bilateral group(62 patients), B1 group were 40 patients, B2 were 22 patients, In the A1 group first cephalad adjacent segment degeneration was noted in 6.5%(2/31), A2 was7.4%(2/27),A1 group second cephalad adjacent segment degeneration was 12.9%(4/31), A2 was14.8%(4/27),and A1 group caudal adjacent segment degeneration was 9.7%(3/31), A2 was 11.1%(3/27).In the bilateral group, B1 and B2 group first cephalad adjacent segment degeneration, second cephalad adjacent segment degeneration and caudal adjacent segment degeneration was 7.5%(3/40), 9.1%(2/22), 15%(6/40), 18.2%(4/22), and 10%(4/40),9.1%(2/22),respectively. The occurrence of ASD in first cephalad and caudal adjacent segment was not significantly different between the four groups groups, but that in second cephalad adjacent segment was significantly different between A1 group and A2、B1、B2 groups. A2 and B2 、B2 and B1 group was significantly in second cephalad adjacent segment,respectively. A2 and B1 group was not significantly in second cephalad adjacent segment,Clinical outcomes according to ODI showed significant difference between every groups. Conclusions:Different age patients with single lumbar intervertebral disc herniation using either unilateral or bilateral pedicle screw fixation who managed with posterior lumbar fusion, no matter unilateral pedicle fixation or bilateral pedicle fixation, as the growth of the age, the increase in the incidence of adjacent segment degeneration.unilateral pedicle screw instrumentation showed a lower rate of radiologic ASD, especially in second cephalad adjacent segment, and a better clinical outcome by ODI. Furthermore,unilateral fixation with pedicle screws is more conducive to lumbar function recovery.