Comparison of Modified Cortical Bone Trajectory Screw and Pedicle Screw for Spinal Reconstruction Surgery

Ivan Gonchar, Yoshihisa Kotani and Norimasa Iwasaki

Department of Orthopedic Surgery, Steel Memorial Muroran Hospital, Japan
Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Japan

^*Correspondance to: Yoshihisa Kotani 

 PDF  Full Text DOI: 10.25107/2474-1647.2276

Abstract

Object: Cortical Bone Trajectory (CBT) is a novel instrumentation technique quickly gaining popularity that offers high screw pullout strength and thus might be a solution to the problem of screw loosening in osteoporotic spine. Original method utilizes short small diameter screws compromising anterior load-sharing and screw strength. We modified CBT (mCBT) to use thicker longer screws for better anchor strength. We report the results of 160 consecutive spine reconstruction cases using mCBT and compare them to Pedicle Screw (PS) outcomes in a cohort of 220 patients with minimum follow-up period of two years.Methods: A 160 mCBT cases (mean age 71) and 60 PS cases (mean age 66) with 2-year minimum follow-up were included. Pathology included degenerative spine, deformity, osteoporotic collapse, trauma, infection etc. for mCBT and PS groups alike. All patients were operated by the single surgeon. Surgery included MIS-PLF, MIS-TLIF and deformity correction with various MIS techniques. The bone grafts were performed with either iliac bone or local bone mixed with HA granules. The clinical outcomes were assessed with Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and VAS scoring. We also evaluated the fusion rates and screw loosening using plain X-rays and CT scans.Results: All cases were followed for 24 months or more. Mean number of segments fixed per case was 1.9 in mCBT and 2.1 in PS group. Overall 919 mCBTs and 388 PSs were inserted. Mean operation time was 157 min in mCBT and 177 min in PS group. Mean intraoperative bleeding was 167 ml in CBT and 334 ml in PS group. Both groups had significant improvement of JOABPEQ and VAS values at follow-up without significant difference between groups. There was only one case of mCBT loosening (0.6%) and 16 cases of PS loosening (25%). There was one pseudarthrosis in mCBT (fusion rate 99%) and 6 in PS (fusion rate 90%, 3 cases re-operated with mCBT). There were 2 cases of 4.75 mm diameter CBT screw breakage (both successfully fused). There were no cases of screw breakage since we started to insert mCBT screws 5.5 mm or larger diameter.Conclusion: We introduced CBT to improve anchor strength in osteoporotic spine. We endeavor to improve the bone purchase of original CBT by using thicker and longer screws. Compared to traditional PS, our modified CBT technique demonstrated significantly better fusion rate and significantly less screw loosening. We recommend the use of screws 5.5 mm diameter or larger and greater length. The mCBT was a reliable instrumentation technique for various spinal disorders such as osteoporotic spine, revision surgery, and spinal deformity correction.

Keywords

PS; JOABPEQ; Spinal deformity correction; Minimally invasive spine stabilization (MISt); Spinal reconstruction; Minimally invasive surgery (MIS)

Cite the article

Gonchar I, Kotani Y, Iwasaki N. Comparison of Modified Cortical Bone Trajectory Screw and Pedicle Screw for Spinal Reconstruction Surgery. Clin Surg. 2018; 3: 2276.