[Comparison of clinical outcome between utilized second sacral alar-iliac and iliac screw on kyphoscoliosis patients]

Objective: To compare the clinical outcome and health related quality of life(HRQoL)of patients with degenerative spinal deformity who underwent spino-pelvic fixation utilized second sacral alar-iliac(S(2)AI)with patient utilized traditional iliac screw(IS). Methods: Patients diagnosed as degenerative spinal deformity who underwent spino-pelvic fixation utilized either S(2)AI screw or Iliac screw at Department of Spine Surgery of Drum Tower hospital from January 2013 to January 2016 were retrospectively analyzed. Patients were divided into two groups according to the pelvic fixation technique. Cobb's angle, coronal balance distance(CBD), regional kyphosis(RK), sagittal vertical axis(SVA)were recorded at pre-operation, post-operation and last follow up. The MOS item short from the health survey(SF-36), visual analogue scale(VAS), Oswestry disability index(ODI) were also recorded at pre-operation and last follow up. Five physical examinations were administered to all patient at the last follow up to diagnose sacroiliac joint dysfunction, three tests resulting positive were regarded as dysfunction. Repeated measurement analysis of variance, t-test or non-parametric test was used to analyzed the data, respectively. Results: A total of 22 patients who met the inclusion were recruited in this study. Fourteen patients were utilized S(2)AI screw and 8 patients were utilized iliac screw.There were no significant differences in age, gender, follow up time between two groups. Cobb's angle, CBD, RK, SVA at pre- and post-operation and last follow up showed no significant difference between two groups.SF-36, ODI, VAS at pre-operation and last follow up showed no significant difference between two groups. Compared with baseline, Cobb's angle(44.4°±14.0° vs. 20.2°±7.2° vs. 18.3°±7.1°), C(7)PL-CSVL((25.3±16.0)mm vs. (10.3±5.7)mm vs. (9.2±4.2)mm), RK(33.0°(-12.0°, 50.0°) vs. 20.0°(-33.0°, 8.5°) vs. -19.0°(-29.0°, 19.0°)), SVA((31.5±34.4)mm vs. (12.1±8.4)mm vs. (10.9±7.2)mm), SF36-physical function summary(PCS)(39.8±14.3 vs. 68.2±21.5), SF36-mental component summary(MCS)(44.9±14.8 vs. 73.9±19.9), ODI(37.7±16.9 vs. 19.8±15.8), VAS(4.8±2.1 vs. 1.8±0.9) were significantly improved postoperatively in S(2)AI group(P<0.05). In the IS group, compared with baseline, Cobb's angle(54.3°±18.3° vs. 26.1°±13.2° vs. 25.6°±18.3°), C(7)PL-CSVL((31.0±16.0)mm vs. (13.9±7.0)mm vs. (12.4±6.6)mm), RK (47.0°(15.0°, 57.0°) vs. 4.0°(-10.0°, 16.0°) vs. 7.0°(-9.0°, 12.0°)), SVA((27.1±23.9)mm vs.(13.1±7.5)mm vs. (13.6±6.0)mm), SF36-PCS(29.7±7.1 vs. 61.1±11.2), SF36-MCS(35.9±7.1 vs. 64.0±11.1), ODI(48.6±13.4 vs. 19.0±10.7), VAS(4.9±1.8 vs. 2.6±1.3) were also significantly improved postoperatively(all P<0.05). There were two patients need revision surgery in the IS group due to the instrumentation-related complication. None of the patients in the S(2)AI group needed revision surgery. There were no instances of sacroiliac joint dysfunction in both groups at last follow up. Conclusion: Spino-pelvic fixation utilizing S(2)AI screw could provide similar correction rate to iliac screw and the sacroiliac joint penetration due to S(2)AI won't affect the HRQoL in patient with degenerative deformity who utilized S(2)AI.