1) Demographics and clinical details
The study population demographics and clinical details for the 74 patients are shown in Table 2.
The mean age of patients was 70.4 years in group I and 69.3 years in group II (p = 0.139). There were 14 (35.90%) males in group I and 6 (17.14%) in group II (p = 0.07). The body mass index (BMI) score was not significantly different in group II (25.9 kg/m2) and in group I (24.6 kg/m2) (p =0.231). There were no differences between the groups in preoperative diagnosis. There were no significant differences in medical comorbidity of diabetes (p= 0.630), hypertension (p= 0.501), coronary artery disease (p = 0.431) between the 2 groups.
2) Change of radiographic sagittal alignment parameters
The radiographic measurements of sagittal alignment parameters were summarized in Table 3.
In group I, parameters such as CL, TLK, LL, PT between preoperative and postoperative 1 month values showed improvement at postoperative 1 month and the results were maintained until the ultimate follow-up.
In group II, compared to preoperative parameters, parameters at postoperative 1 month values were as follows showing significant improvement; TLK (4.3 vs 1.9, p=0.021), LL (-29.8 vs -42.3, p<0.001) and PT (24.7 vs 20.5, p=0.021), respectively. Among the improved parameters at postoperative 1 month, these results were not maintained and some parameters were significantly deteriorated at the ultimate follow-up; TLK (1.9 vs 3.8, p=0.160), LL (-42.3 vs -35.9, p=0.041) and PT (20.5 vs 24.3, p=0.019).
In comparison between group I and II, both postoperative radiographic values at postoperative 1 month were not significantly different in TLK, LL, PT(p>0.05). At the ultimate follow-up, significant differences were found in TLK (1.2 vs 3.8, p=0.022), LL (-43.4 vs -35.9, p=0.015), respectively. Moreover, the amount of changes in LL between the preoperative and the ultimate follow-up (-12.3 vs -3.1, p=0.031) and between the postoperative 1 month and the ultimate follow-up (1.4 vs 6.4, p=0.042) were also significantly different.
3) Change of radiographic sagittal balance parameters
The radiographic measurements of sagittal balance parameters were summarized in Table 4.
In group I, between the preoperative and the postoperative 1 month values, all parameters showed improvement such as C7SVA (39.2 vs 23.2, p<0.001), CrSVA-S (50.2 vs 31.5, p<0.001), CrSVA-H (-19.1 vs -8.5, p<0.001), respectively. The immediate improvement achieved at 1 month were maintained in all parameters until the ultimate follow-up.
In group II, compared to preoperative parameters, parameters at postoperative 1 month values were as follows showing significant improvement; C7SVA (47.3 vs 28.3, p<0.001), CrSVA-S (48.9 vs 33.5, p<0.001), CrSVA-H (-18.0 vs -9.6, p<0.001), respectively. In all 3 parameters, the improvement at postoperative 1 month were significantly deteriorated at the ultimate follow-up; C7SVA (28.3 vs 47.3, p<0.001), CrSVA-S (33.5 vs 45.5, p<0.001), CrSVA-H (-9.6 vs -16.6, p=0.008).
Between the group I and II, both postoperative radiographic values at postoperative 1 month were not significantly different in C7SVA (23.2 vs 28.3, p=0.125), CrSVA-S (31.5 vs 33.5, p=0.333), CrSVA-H (-8.5 vs -9.6, p=0.425), respectively. At the ultimate follow-up, significant differences were found in C7SVA (22.1 vs 43.7, p<0.001), CrSVA-S (33.2 vs 45.5, p<0.001), CrSVA-H (-7.2 vs -16.6, p<0.001), respectively. Furthermore, in terms of amount of changes, there were significant differences between the preoperative and the ultimate follow-up in C7SVA (-17.1 vs -3.6. p<0.001), CrSVA-S (-17.0 vs -3.4, p=0.021) and CrSVA-H (11.9 vs 1.4, p<0.001). Also, there were significant differences in amount of the changes between the postoperative 1 month and the ultimate follow-up in C7SVA (-1.1 vs 15.4, p<0.001), CrSVA-S (1.7 vs 12, p<0.001) and CrSVA-H (1.3 vs -7.0, p=0.022).
4) The changes in scores of clinical parameters
The clinical results were summarized in Table 5.
Clinical parameters compared between the preoperative and the ultimate values in group I showed significant improvement in ODI (%) (47.1 vs 21.5, p<0.001), SRS total score (%) (50.8 vs 78.8, p=0.005), pain (1.7 vs 3.6, p<0.001), self-image (2.9 vs 4.2, p<0.001), function (2.5 vs 3.9, p<0.001), and satisfaction (2.6 vs 4.2, p<0.001), respectively.
Clinical parameters compared between the preoperative and the ultimate values in group II showed significant improvement in ODI (%) (45.0 vs 32.9, p=0.011), SRS subscore of pain (1.4 vs 3.1, p<0.001), self-image (2.8 vs 3.9, p=0.042) and function (2.6 vs 3.3, p=0.044), respectively.
In comparison of scores of clinical parameters between the groups, it was not different in preoperative ODI (%) (47.1 vs 45.0, p=0.501). ODI at the ultimate follow-up compared to the preoperative improved in each group (21.5, p<0.001; 32.9, p<0.011). Between the groups, there were significant differences in ODI at the ultimate follow-up (21.5 vs 32.9, p<0.001) and the amount of improved ODI (-25.6 vs -12.1, p<0.001), showing superiority in group I. Regarding SRS-22 scores, there were no significant differences between the groups preoperatively. At the ultimate follow-up, however, values in group I was higher in SRS total score (%) (78.8 vs 67.6, p=0.037), and satisfaction (4.2 vs 3.0, p<0.001). The amount of improvement in group I was higher in SRS score of total (%) (28 vs 20, p=0.037), function (1.4 vs 0.7, p<0.016), and satisfaction (1.6 vs 0.6, p<0.001).