Experience of 100 Consecutive Spine Reconstructions using Cortical Bone Trajectory (CBT) screws vs Traditional Pedicle Screws

Presented at SMISS Annual Forum 2014
By Ivan Gonchar MD
With Yoshihisa Kotani MD, PhD, Yuki Matsui MD, Takuji Miyazaki MD, Toshiyuki Kasemura MD, Tatsuya Masuko MD, PhD,

Disclosures: Ivan Gonchar MD None Yoshihisa Kotani MD, PhD None, Yuki Matsui MD None, Takuji Miyazaki MD None, Toshiyuki Kasemura MD None, Tatsuya Masuko MD, PhD None,

Introduction:
Since 2012 we use cortical bone trajectory (CBT) technique for spine reconstruction in cases of spine deformity, degenerative disease, osteoporotic vertebral collapse, trauma and other pathology.

Aims/Objectives:
We report the clinical outcomes of 100 consecutive cases using CBT screws and compare them to traditional pedicle screw (PS) results.

Methods:
100 patients who underwent spine reconstructions using CBT(mean age 71 yrs) and 63 patients operated using PS (mean age 66 yrs) were included. The target pathology included degenerative lumbar spine disease, spine deformity, osteoporotic vertebral collapse, spine trauma, infection and others for CBT and PS groups alike.The procedures included MIS-PLF or 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), Oswestry Disability Index (ODI) and VAS scoring. We also evaluated the rates of pseudarthrosis and screw loosening.

Results:
Mean number of segments fixed was 1.6 in CBT and 2.1 in PS group. Overall 523 CBTs and 388 PSs were inserted. Mean operation time was 162 min. in CBT and 177 min. in PS. Mean intraoperative bleeding was 177 ml in CBT and 334 ml in PS. Mean preop ODI score was 43% in CBT and 45% in PS. Both groups showed significant improvement of JOABPEQ, ODI and VAS values at follow-up. There was no statistically significant difference between two groups in terms of JOABPEQ, ODI and VAS values. There was only one case of CBT loosening (1%) and 16 cases of PS loosening (25%). There was one pseudarthrosis in CBT(fusion rate 99%) and 6 pseudarthrosis in PS (fusion rate 90%). There were 2 cases of 4.75 mm diameter CBT screw breakage, however, both cases let to successful fusion. There were no cases of screw breakage after we started to insert CBT screws 5.5 mm or larger diameter. The rod application is sometimes challenging in thoracolumbar region and when L4 and L5 CBTs have to be connected to S2 alar iliac screws (S2AIS).

Conclusions:
CBT provided excellent fusion rate and proved a suitable anchor for conventional MIS and deformity correction in osteoporotic spine. We recommend the use of screws 5.5 mm diameter or larger and greater length. Special attention should be paid to screw entry point and trajectory in transitional areas where CBTs have to be aligned with thoracic PS or S2AIS.