Friday, September 28, 2018 10:30 AM–12:00 PM abstracts: deformity: technical factors: 170. Comparison of three lumbopelvic fixation techniques in long fusion to the sacrum in osteoporotic adult spinal deformity patients (>60 years): clinical and radiological outcomes

Abstract

BACKGROUND CONTEXT Iliac screw techniques provide additional biomechanical stabilization to S1 in long fusion to the sacrum. Recently S2 Alar iliac screw (S2AI) fixation became more popular than traditional iliac screw (TIS) (entry point posterior superior iliac spine), and distal iliac screw (DIS) (entry point posterior inferior iliac spine) due to the lower implant profile and need for less extensive soft tissue dissection. S2AI fixes the sacroiliac (SI) joint differently from TIS and DIS. PURPOSE This study aimed to compare the clinical and radiologic outcomes between TIS, DIS and S2AI fixation in osteoporotic adult spinal deformity patients. STUDY DESIGN/SETTING Retrospective. PATIENT SAMPLE A total of 158 adult spinal deformity patients. OUTCOME MEASURES ODI questionnaire was evaluated for clinical outcome. METHODS A total of 158 (103f, 55m) adult spinal deformity patients pts who underwent long fusion to the sacrum with three different iliac screw techniques (TIS, DIS, S2AI) were reviewed. Radiologic parameters were compared between preop and f/up standing x-rays. Hospital charts and f/up CT scans were used to compare the screw lengths, diameters, and implant related complications including S1 and iliac screw loosening, rod breakage, sacroiliac joint dissociation (SID), surgical site infections (SSI) and hematoma. ODI scores were compared for clinical assessment. RESULTS A total of 54 patients had TIS, 51 patients had DIS, 53 patients had S2AI fixation. Mean ages were 67, 71, 68; mean f/up was 54.2 (24–174) months, respectively. Iliac screw lengths were 85mm, 90mm, 105mm; diameters were 9.0mm, 8.5mm, 9.5mm for TIS, DIS, S2AI, respectively. There were seven patients (12.9%) in TIS, six patients (11.7%) in DIS & three patients (5.6%) in S2AI with implant related complications. One patient (1.8%) in TIS and one patient (1.9%) in DIS group showed SID (TIS=1, DIS=1, S2AI=0). Postop hematoma was detected in 14 patients (8.8%) (TIS=4, DIS=7, S2AI=3) and SSI developed in two patients (1.2%) (TIS=1, DIS=1, S2AI=0). ODI scores improved in all groups. CONCLUSIONS All techniques provided sufficient stability for lumbosacral fusion in adult spinal deformity patients. S2 Alar iliac screw technique showed lower implant related complication rates when compared to both iliac screw techniques. Traditional iliac screwand Distal iliac screw had higher rates of hematoma and surgical site infections due to extensive soft tissue dissection compared to S2 Alar iliac screw. S2 Alar iliac screw does not lead to sacroiliac joint dissociation as it provides stability by fixing the sacroiliac joint.