Minimally Invasive Midline Pars-Cortical Screw Techniques
The cortical screw trajectory is an evolution of the technique used for traditional pedicle screw placement. The novel cortical screw trajectory aims to increase screw purchase with the preferential capture of more cortical bone rather than cancellous bone located within the pedicles. This pathway also has the benefit of a smaller window of exposure required for placement, and thus lends itself for application in minimally invasive techniques. This chapter will explore the biomechanical advantages of cortical screw placement compared to traditional pedicle screws. It will also review the radiographic and anatomic landmarks required for safe insertion. Literature regarding clinical outcomes of cortical screw based procedures will be discussed.
KeywordsCortical screw Cortical screw trajectory Minimally invasive fusion Pars screw trajectory
- 2.Harrington PR. The history and development of Harrington instrumentation: the classic. Clin Orthop. 1977;227:3–6.Google Scholar
- 14.Sansur CA, Caffes NM, Ibrahimi DM, Pratt NL, Lewis EM, Murgatroyd AA, Cunningham BW. Biomechanical fixation properties of cortical versus transpedicular screws in the osteoporotic lumbar spine: an in vitro human cadaveric model. J Neurosurg Spine. 2016;25(4):467–76.. Epub 2016 May 13CrossRefGoogle Scholar
- 16.Kasukawa Y, Miyakoshi N, Hongo M, Ishikawa Y, Kudo D, Shimada Y. Short-term results of Transforaminal lumbar interbody fusion using pedicle screw with cortical bone trajectory compared with conventional trajectory. Asian Spine J. 2015;9(3):440–8. https://doi.org/10.4184/asj.2015.9.3.440. Epub 2015 Jun 8.CrossRefPubMedPubMedCentralGoogle Scholar
- 18.Sakaura H, Miwa T, Yamashita T, Kuroda Y, Ohwada T. Posterior lumbar interbody fusion with cortical bone trajectory screw fixation versus posterior lumbar interbody fusion using traditional pedicle screw fixation for degenerative lumbar spondylolisthesis: a comparative study. J Neurosur: Spine. 2016;25(5):591–5.Google Scholar
- 20.Rampersaud YR, Gray R, Lewis SJ, Massicotte EM, Fehlings MG. Cost-utility analysis of posterior minimally invasive fusion compared with conventional open fusion for lumbar spondylolisthesis. SAS J. 2011;5(2):29–35. https://doi.org/10.1016/j.esas.2011.02.001. eCollection 2011.CrossRefPubMedPubMedCentralGoogle Scholar