Multi-Rod Constructs Can Increase the Incidence of Iliac Screw Loosening after Surgery for Adult Spinal Deformity
- Author:
Tomohiro BANNO
1
;
Tomohiko HASEGAWA
;
Yu YAMATO
;
Daisuke TOGAWA
;
Go YOSHIDA
;
Sho KOBAYASHI
;
Tatsuya YASUDA
;
Hideyuki ARIMA
;
Shin OE
;
Yuki MIHARA
;
Hiroki USHIROZAKO
;
Yukihiro MATSUYAMA
Author Information
- Publication Type:Original Article
- Keywords: Adult spinal deformity; Complication; Iliac screw; Multi-rod construct; Screw loosening; Adult spinal deformity
- MeSH: Adult; Bone Density; Congenital Abnormalities; Female; Humans; Incidence; Kyphosis; Male; Osteoporosis; Osteotomy; Retrospective Studies; Spine
- From:Asian Spine Journal 2019;13(3):500-510
- CountryRepublic of Korea
- Language:English
- Abstract: STUDY DESIGN: A retrospective study. PURPOSE: To investigate the incidence of iliac screw loosening with a two-rod vs. multi-rod construct and the effect on clinical and radiographic outcomes after surgery for adult spinal deformity (ASD). OVERVIEW OF LITERATURE: Multi-rod construct is useful for preventing rod fracture in ASD surgery. However, limited information is available regarding the incidence of iliac screw loosening after corrective fusion surgery using a multi-rod construct. METHODS: Total 106 patients with ASD (24 men and 82 women; mean age, 68 years) who underwent corrective fusion surgery using bilateral iliac screws and were followed up for at least 1 year were reviewed. The following variables were compared between patients who underwent surgery with a two-rod and multi-rod construct: age, sex, bone mineral density (BMD), fusion level, high-grade osteotomy, L5/S interbody fusion, screw loosening (upper instrumented vertebra [UIV], S1, and iliac), rod fracture, proximal junctional kyphosis, spinopelvic parameters, and Oswestry Disability Index (ODI) score. We also compared patients with and without iliac screw loosening in the multi-rod construct group. RESULTS: Of the 106 patients, 55 underwent surgery with a conventional two-rod construct and 51 with a multi-rod construct (three rods in 16, four rods in 35). Iliac and UIV screw loosening was observed in 24 patients (21%) and 35 patients (33%), respectively. The multi-rod group showed significantly higher incidence of iliac and UIV screw loosening and lower incidence of rod fracture. Patients with iliac screw loosening had a lower BMD than those without screw loosening; however, no significant differences were observed in the spinopelvic parameters or the ODI score. CONCLUSIONS: The use of multi-rod constructs led to a higher incidence of junctional screw loosening than the use of conventional two-rod constructs, especially in patients with osteoporosis. Iliac screw loosening did not affect sagittal alignment or clinical outcome in the short term.
