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OBJECTIVE: To compare short-term clinical and radiological outcomes and complication profiles between bilateral dual sacral-2-alar-iliac (S2AI) screw and bilateral single S2AI screw fixation techniques in patients who underwent grade 3 or 4 spinal osteotomies. METHODS: A retrospective review of 83 patients treated with bilateral dual S2AI screws and 32 patients treated with bilateral single S2AI screws was conducted between 2018 and 2020 with a minimum 1-year follow-up. Clinical and radiological outcomes of patients and incidence of perioperative complications, including rod breakage, screw dislodgment, proximal junctional kyphosis, proximal junctional failure, need for reoperation, and systemic adverse effects, were collected and statistically compared between the groups. RESULTS: With a mean follow-up of 18.2 months, rod fracture (6.0% vs. 18.7%, P = 0.03), screw dislodgment (0 vs. 12.5%, P < 0.01), and S2AI screw loosening (1.2% vs. 18.7%, P < 0.01) were significantly lower in the dual S2AI screws group than in the single S2AI screws group. However, the reoperation rate was similar between the 2 groups (24.1% vs. 34.3%, P = 0.26). No significant differences in clinical and radiological outcomes as well as proximal junctional kyphosis (10.8% vs. 18.7%, P = 0.25) and proximal junctional failure (9.6% vs. 18.7%, P = 0.18) were identified between the 2 groups. CONCLUSIONS: The dual S2AI screw fixation technique showed more advantages over the single S2AI screw fixation technique with reduced incidence of screw dislodgment, rod fractures, and sacral-alar-iliac screw loosening.
RESUMEN
STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The S2-alar-iliac (S2AI) technique has been described as an alternative method for pelvic fixation in place of iliac screws (ISs) in spinal deformity surgery. The objective of this study was to analyze the impact of S2AI screws on radiographical outcomes, including spinopelvic parameters. METHODS: A retrospective review of 17 patients receiving ISs and 46 patients receiving S2AI screws for correction of adult spinal deformity between 2010 and 2015 with minimum 1-year follow-up was conducted. Patient data on postoperative complications, including reoperation rates and proximal junctional kyphosis (PJK), and radiographical parameters was collected and statistically analyzed. RESULTS: With mean follow-up of 21.1 months, the overall reoperation rate was significantly lower in the S2AI group than in the IS group (21.7% vs 58.8%, P = .01), but the incidence of PJK was similar (32.6% vs 35.3%, P > .99). Moreover, the time to reoperation in the IS group was significantly shorter than in the S2AI group (P = .001), and the S2AI group trended toward a longer time to reoperation due to PJK (P = .08). There was a significantly higher change in pelvic incidence (PI) in the S2AI group (-6.0°) compared with the IS group (P = .001). CONCLUSIONS: Compared with the IS technique, the S2AI technique demonstrated a lower rate of overall reoperation, a similar rate of PJK, longer time to reoperation, and possible reduction in PI. Future studies may be warranted to clarify the mechanism of these results and how they can be translated into improved patient care.
RESUMEN
BACKGROUND: In sacropelvic fixation, the iliac screw technique offers biomechanically strong constructs, but its disadvantages include screw prominence, wound dehiscence, and postoperative pain secondary to the high profile nature. To overcome this drawback, S2-alar-iliac (S2AI) screws were developed as an alternative technique for sacropelvic fixation. This study aimed to compare the S2AI screw technique with the iliac screw technique in terms of postoperative symptomatic screw prominence. METHODS: A retrospective review of the records of sacropelvic fusion procedures performed at a single institution between October 2010 and January 2015 identified 32 patients with 72 iliac screws and 68 patients with 148 S2AI screws, and clinical and radiographic data were collected. If a patient had wound dehiscence and/or tenderness in the buttock immediately overlying a pelvic screw head postoperatively, it was defined as symptomatic screw prominence. The minimal distance from screw head to skin (MDSS) on postoperative computed tomography scans was measured for each patient to clarify the relationship between symptomatic screw prominence and MDSS. RESULTS: Mean follow-up period was 22.0 months. There was significantly more symptomatic pelvic screw prominence in the iliac screw group (11.1% vs. 1.4%, P = 0.002). MDSS ≤23 mm was the strongest predictor of symptomatic pelvic screw prominence, which yielded sensitivity of 100%, specificity of 94.1%, positive predictive value of 47.6%, and negative predictive value of 100%. CONCLUSIONS: The use of the S2AI screw technique resulted in a reduced rate of symptomatic screw prominence. MDSS ≤23 mm was the strongest predictor of symptomatic screw prominence.