RESUMO
Objective:To evaluate the clinical outcomes and complications of second sacral alar-iliac (S 2AI) technique utilized in degenerative spinal deformity patients, and to analyze the potential risk factors for postoperative sagittal imbalance. Methods:From January 2014 to October 2020, a consecutive cohort of 39 degenerative spinal deformity patients who were treated with S 2AI were retrospectively reviewed, including 4 males and 35 females, aged 63.1±6.7 years (range, 43-73 years). All of the patients had a minimum of 2-year follow-up. According to the sagittal vertical axis (SVA) at the final follow-up, patients were divided into 2 groups. Sagittal balance group (SVA≤50 mm) and sagittal imbalance group (SVA>50 mm). Radiographic parameters including the Cobb's angle, coronal balance distance (CBD), thoracic kyphosis (TK), lumbar lordosis (LL), SVA, pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS) were measured in the standing radiographs before and after operation and at the latest follow up. Comparison was made between the two groups and the differences with statistical significance were analyzed with binary logistic regression analysis. Intraoperative and postoperative complications were recorded. The Scoliosis Research Society-22 (SRS-22) score were employed to evaluate the quality of life. Results:The average follow-up period was 30.3±9.1 months (range, 43-73 months). Eighteen patients (46%) were identified with sagittal imbalance at the last follow-up. Compared with the patients in the sagittal balance group, the preoperative SVA was significantly larger (83.1±56.2 mm vs. 48.1±51.1 mm, t=2.04, P=0.049) and the postoperative TK was significantly greater (27.8°±9.6° vs. 18.9°±13.4°, t=2.36, P=0.024) for patients in the sagittal imbalance group. Scores of pain domain (3.2±0.5 vs. 3.7±0.6) and self-image domain (3.4±0.8 vs. 3.8±0.6) in sagittal imbalance group were significantly lower than those of sagittal balance group ( P<0.05). Logistic regression analysis showed that larger preoperative SVA ( OR=1.02, P=0.028) and greater postoperative TK ( OR=1.09, P=0.022) were independent risk factors for the occurrence of sagittal imbalance during the follow-up periods. Conclusion:S 2AI screw fixation can achieve satisfying coronal deformity correction and great sagittal reconstruction after surgery in patients with degenerative spinal deformity. However, sagittal imbalance may still occur during the follow-up periods. Larger preoperative SVA and greater postoperative TK are independent risk factors for the occurrence of sagittal imbalance.
RESUMO
Objective To evaluate the accuracy and safety of screw placement position through second sacral alar -iliac(S2AI)with in-teroperative cone beam CT(CBCT)scan.Methods Collected 22 patients who underwent second sacral alar-iliac screw implant surgery in our hospital from June 2015 to June 2017.All the patients had intraoperative CBCT scan and conventional CT scan after operation.Regard the postoperative CT scan imageing as gold standard to assess the accuracy and safety of S 2AI screws position.The S2AI tract parameters were measured with intraoperative CBCT images and postoperative CT images respectively.Results There was no significant difference between the S2AI tract parameters which were measured with intraoperative CBCT images and postoperative CT images(P>0.05).Conclusion The intraoperative CBCT scan could accurately evaluate the position of S 2AI screws,as well as clarify the damage of the inner and outer plate of the iliac bone in the process of fixation.Compared with postoperative conventional CT scan,the intraoperative CBCT scan can potentially re-duce the reoperation rate.