Minimal invasive surgical technique in midline lumbar inter-body fusion: A technique note

Midline lumbar inter-body fusion (MIDLF) surgery with cortical bone trajectory (CBT) screw insertion is a modern fusion technique for spinal surgery. The difference in entry point of this trajectory from conventional pedicle screw surgery offers the potential benefits of less soft tissue dissection and reduced blood loss, post-operative wound pain, and infection risks. Because this is a newly developed technique first announced by Santoni in 2009, most surgeons perform this surgery in a mini-open fashion and require more intra-operative fluoroscopy and ionizing radiation exposure during screw placement. In this article, we demonstrate a minimally invasive midline lumbar interbody fusion (MIS-MIDLF) technique with percutaneous CBT screw placement. Using a designed cannulated awl, we only need a single dimensional fluoroscopy view from anterior to posterior (AP view) to achieve an accurate trajectory and therefore reduce radiation exposure. We report our first ten consecutive patients with degenerative spondylolithesis who underwent MISS-MIDLF and were followed up for more than 18 months. The procedure required a single wound of about 3 cm in length in one to two level fusion surgery and only three to four shots of fluoroscopy were needed for each screw placement. There were no screws malpositioned in subsequent plain films or computer tomography scans. We demonstrate a case with detailed surgical procedures and provide this technique as an alternative approach for surgeons performing MILDF surgery.