- Baseline information.
The average follow-up period of the 104 patients included in this study was 32 months. According to the grouping method, eligible patients were divided into study and control groups: group A (study/unstable group: 52 cases), and group B (control/stable group: 52 cases). Group A was further divided into group A1 (slip instability: 27 cases) and A2 (angular instability: 25 cases). The clinical characteristics of groups A1 and A2 were compared with group B, respectively, and their baseline data tested using the χ2 test or Fisher exact probability method. Tested data included screw type, number of fusion segments, operation time, follow-up duration, among others. Results were considered not to be statistically different when P > 0.05. See Table 1-1 and Table 1-2 for details.
- Preoperative imaging parameters.
Among the cases reviewed, the preoperative slip distance and slip rate were found to be higher in patient in group A1 in comparison to group B; however, the difference was not statistically significant (P > 0.05). Also, the preoperative segment angle difference among patients in group A2 were higher compared to those in group B, the difference however, was not statistically significant (P > 0.05). The detailed results are shown in Figure 2.
- Correction of slippage reset.
The comparison of the preoperative and POD 3 lumbar lateral X-rays revealed no statistically significant difference in the slippage correction rate, segment angle correction, and slip distance between patients in group A1 and those in group B (P > 0.05). The comparison of the average values of the two indexes (slippage rate correction and slip distance correction) between groups A2 and B revealed that the indexes in group A2 were higher than those in group B. On the contrary, the average segmental angle of patients in group B were higher than those in group A2. The differences among the three indicators between the two groups, however, were not statistically significant (P > 0.05). See Figure 3 for details.
- Comparison of the pedicle screw typesused for reductionand correction.
Data of patients in the three groups (A1, A2, and B) were analyzed in accordance with the type of pedicle screw used (normal screws or puller screws) for the correction of spondylolisthesis. Patients in groups A1 and B, who used puller pedicle screws, achieved better correction and correction than patients who used normal pedicle screws. There was a statistically significant difference between the slippage correction and slip distance correction rates. However, there was no statistically significant difference in the segmental angular correction rate. There was no statistically significant difference in the correction rates of spondylolisthesis, segmental angle correction, and sliding distance correction in group A2 patients who used normal pedicle screws or puller screws. See Figure 4 for details.
- JOA scores analysis
The total JOA score for the study population was 29 points, with the lowest score signifying severe dysfunction[12]. The postoperative improvement rate was calculated by subtracting the pretreatment score from the posttreatment score, then dividing the outcome with the outcome of the 29 minus posttreatment score. We observed that the preoperative score for groups A1 and A2 were lower than that of group B, and the difference was statistically significant (P <0.05); however, this outcome was reversed at one month postoperative in both groups (A1 and A2). The analysis of the last follow-up data revealed no statistically significant difference in the JOA scores between groups A1 and B, as well as A2 and B. The one month postoperative and last follow-up improvement rate for patients in group A1 were higher than those in the B group, and the difference was statistically significant (P <0.05). There was a statistically significant difference between the improvement rate in group A2 when compared to group B (P <0.05), but there was no statistically significant difference in the improvement rate at the last follow-up (P > 0.05). See Figure 5 for details.
- VAS scores for lower back and limb pain
The VAS scoring, which is used to evaluate the patient’s pain severity subjectively, has a scoring system with 0 signifying no pain, and 10 for unbearable/severe pain. The average preoperative VAS scores for groups A1 and A2 were higher than that of group B. On the contrary, the average at one month postoperative was lower than group B. At the last follow-up, the average scores for patients in group A1 were lower than those in group B, while that of group A2 were higher than those in group B. At the last follow-up, the average scores for groups A1 and A2 were lower than those of group B. See Figure 6 for details.
- The occurrence of complications.
Among the 104 cases reviewed, 58 patients developed temporary intestinal paralysis, and eight patients developed wound infection, seven patients developed CSF leakage, five patients developed nervous system-related injuries, while two patients developed urinary system-related complications. There were no statistically significant differences in the incidence of complications among the five main postoperative complications between groups A1 and B, and groups A2 and B (p > 0.05). See Figure 7 for details.