Saturday, September 29, 2018 10:30 am–12:00 pm Applying Deformity Concepts in Your Practice: 282. Complications after spinopelvic fixation with Iliac Screws in 260 adult patients with 2-year minimum follow-up

BACKGROUND CONTEXT Pelvic fixation has a pivotal role in promoting fusion at the lumbosacral junction after instrumented spine surgery. Iliac screws have a long, established history of being utilized for spinopelvic fixation. However, pelvic fixation remains challenging. Recent literature describing complications associated with iliac screw fixation in adult patients has been limited. PURPOSE The purpose of this study was to report our experience with iliac screw fixation in a large series of adult patients with a 2-year minimum follow-up. STUDY DESIGN/SETTING Retrospective review of a prospectively maintained single-institution, multisurgeon database. PATIENT SAMPLE Consecutive patients undergoing spinopelvic fixation with iliac screws. OUTCOME MEASURES Complications and reoperation rates. METHODS A total of 327 adult patients undergoing spinopelvic fixation with iliac screws at our institution between 2010 and 2015, 260 met the studyu0027s inclusion criteria (age ≥ 18 years, first-time iliac screw placement, and 2-year minimum clinical and radiographic follow-up). Patients with evidence of active spinal infection were excluded. All iliac screw heads were deeply recessed into the posterior superior iliac spine to avoid prominence. Clinical and radiographic data, including complications, were obtained and then analyzed. Univariate and/or multivariate analyses were used to assess complications. RESULTS A total of 20 patients (7.7%) had iliac screw failure, which included fracture (12, 4.6%) and loosening (9, 3.5%). One patient had both fracture and loosening. No patients had iliac screw head prominence that required revision surgery, caused pain, caused wound dehiscence over the screw head, or produced poor cosmesis. Eleven (4.2%) patients had rod fracture below S1. A total of 23 patients (8.8%) had L5/S1 pseudarthrosis. Of the patients with iliac screw fracture or loosening, solid fusion at L5/S1 was seen in eight (66.7%) and five (55.6%) patients, respectively. All patients with rod fracture below S1 had solid fusion at L5/S1. Four patients (1.5%) had fracture of the S1 screw. Seven patients (2.7%) had wound dehiscence (unrelated to the iliac screw head) or infection. Our rate of reoperation (excluding revisions for PJK) was 17.7% (46). On univariate analysis, iliac screw failure was significantly associated with revision fusion (70.0% vs. 41.2%, p=.013), greater number of instrumented vertebra (12.6 vs. 10.3, p=.014), and greater postoperative pelvic tilt (27.7 vs. 23.2, p=.04). Lumbosacral junction complication was significantly associated with greater number of instrumented vertebra (12.6 vs. 10.3, p=.014). Reoperation was significantly associated with younger age at surgery (61.8 vs. 65.8, p=.014, greater number of instrumented vertebra (12.2 vs. 10.2, p=.001), and longer clinical and radiographic follow-up (55.8 vs. 44.5, p CONCLUSIONS Previous studies on iliac screw fixation have reported high rates of complications and reoperation, and alternative fixation techniques have been proposed in response. In this large, single-center series of adult patients, iliac screws were an effective method of spinopelvic fixation with high rates of lumbosacral fusion and lower complication rates than previously reported. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.