Search results
A total of 2437 studies via searching electronic databases presented, there were 997 articles after removed the duplicates. Strictly along with our inclusion and exclusion criteria, 33 studies were included, afterward, we retained 10 full-text articles assessed for eligibility. 6 studies [2-4, 12, 16, 17] were eventually accepted.
Quality assessment and demographics
Two-thirds of the included studies showed a low risk of bias for sequence generation and selective reporting, all showed low risk for blinding of outcome assessment and incomplete outcome data. Herkowitz’s study[12] assessed the allocation concealment as high risk, the other five studies didn’t mention this criterion. The results of the quality assessment of trials were provided in Table1. A total of 650 patients diagnosed with LDS were enrolled, hailing from the USA, Sweden, and Japan. Of these 650 patients, 275 were randomized to the decompression (D) group versus 375 to the decompression combined with fusion (D+F) group. Recruitment periods approximately ranged from 3 to 7 years. No statistic value was found in average age (P=0.99) and gender (P=0.47) between D and D+F groups. More details were depicted in Table2.
Outcomes
VAS score
VAS grades from 0, meaning no pain, to 10, representing maximal pain[18]. There were four RCTs[3, 4, 12, 16] mentioned the improvement ratio of the VAS score of low back pain before and after given decompression or fusion treatment. Postoperative pain easement assessed by VAS didn’t show significant value in our study (WMD, -0.045; 95% CI, -1.259 to 1.169; P=0.942, Figure2), and the heterogeneity is non-negligible (I2=75.1%; p=0.007). Two RCTs[3, 4] worked out no statistic difference between two groups on the number of those who got improved VAS scores after taking surgery (OR, 0.77; 95% CI, 0.36 to 1.65; P=0.50). Three trials[3, 4, 12] described the VAS score of the leg pain pre- and post-operation, and we worked out the postoperative easement between groups as no significant difference (WMD, 0.075; 95% CI, -1.201 to 1.351; P=0.908, Figure3).
ODI score and EQ-5D score
ODI ranges from 0 to 100, EQ-5D ranges from 0 to 1, respectively, ODI score is parallel with the severity of the disability, so is EQ-5D score with the quality of life [19]. Two RCTs [4, 17] referred to ODI and EQ-5D indicators. However, our meta-analysis via random effect model performed no statistic difference between the D and D+F groups in ODI score (WMD, 1.489; 95% CI, -7.232 to 10.211; P=0.738; Figure4) and EQ-5D score (WMD, 0.03; 95% CI, -0.05 to 0.12; P=0.43).
Odom’s classification
Postoperative patients’ satisfaction was evaluated by Odom’s classification. Our meta-analysis worked out no statistical difference between the D and D+F groups (OR, 0.353; 95% CI, 0.113 to 1.099; P=0.072; Figure5). Restored walking ability was only seen in Forsth’s literature[4], and reported no statistical difference in the number of patients in the increase of walking distance at 2 years as well.
Complications
Five articles[2-4, 16, 17] recorded the incidence of complications, among which there were two articles[4, 17] mentioned ASD. Forsth’s trial[4] was eliminated because of recording both spondylolysis and non-spondylolysis. Analysis towards the other four articles was regarded as no statistic difference between the D and D+F groups (OR= 0.437; 95% CI, 0.065 to 2.949; P=0.395; Figure6). Ghogawala et al.[17] recorded the cases of ASD in two groups respectively as 12 and 4, both were adjacent segment disease and took the secondary surgery.
Re-operation
Three publications[2, 16, 17] reported the incidence of re-operation. The average rates in the D group were 18.2%, while that one in the D+F group was 7.3%. No statistical difference was found between two groups (OR, 2.541; 95% CI, 0.897 to 7.198; P=0.079; Figure7).
Postoperative degenerative spondylolisthesis progression
In both groups, a certain proportion of postoperative degenerative spondylolisthesis happened at follow-up and immediate post-operation. Two RCTs[2, 12] referred to the number of degenerative spondylolisthesis progression and were verified no statistics difference (OR=8.59,P=0.27).