The Effects of Spinopelvic Parameters and Paraspinal Muscle Degeneration on S1 Screw Loosening.
10.3340/jkns.2015.58.4.357
- Author:
Jin Bum KIM
1
;
Seung Won PARK
;
Young Seok LEE
;
Taek Kyun NAM
;
Yong Sook PARK
;
Young Baeg KIM
Author Information
1. Department of Neurosurgery, Chung-Ang University Hospital, Seoul, Korea. nspsw@cau.ac.kr
- Publication Type:Original Article
- Keywords:
Lumbosacral region;
Pedicle screws;
Instrumentation;
Muscle;
Spinal fusion;
Risk factors
- MeSH:
Bone Density;
Humans;
Incidence;
Lumbosacral Region;
Magnetic Resonance Imaging;
Muscles;
Paraspinal Muscles*;
Risk Factors;
Spinal Fusion
- From:Journal of Korean Neurosurgical Society
2015;58(4):357-362
- CountryRepublic of Korea
- Language:English
-
Abstract:
OBJECTIVE: To investigate risk factors for S1 screw loosening after lumbosacral fusion, including spinopelvic parameters and paraspinal muscles. METHODS: We studied with 156 patients with degenerative lumbar disease who underwent lumbosacral interbody fusion and pedicle screw fixation including the level of L5-S1 between 2005 and 2012. The patients were divided into loosening and non-loosening groups. Screw loosening was defined as a halo sign larger than 1 mm around a screw. We checked cross sectional area of paraspinal muscles, mean signal intensity of the muscles on T2 weight MRI as a degree of fatty degeneration, spinopelvic parameters, bone mineral density, number of fusion level, and the characteristic of S1 screw. RESULTS: Twenty seven patients showed S1 screw loosening, which is 24.4% of total. The mean duration for S1 screw loosening was 7.3+/-4.1 months after surgery. Statistically significant risk factors were increased age, poor BMD, 3 or more fusion levels (p<0.05). Among spinopelvic parameters, a high pelvic incidence (p<0.01), a greater difference between pelvic incidence and lumbar lordotic angle preoperatively (p<0.01) and postoperatively (p<0.05). Smaller cross-sectional area and high T2 signal intensity in both multifidus and erector spinae muscles were also significant muscular risk factors (p<0.05). Small converging angle (p<0.001) and short intraosseous length (p<0.05) of S1 screw were significant screw related risk factors (p<0.05). CONCLUSION: In addition to well known risk factors, spinopelvic parameters and the degeneration of paraspinal muscles also showed significant effects on the S1 screw loosening.
