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Clinical Outcomes With Midline Cortical Bone Trajectory Pedicle Screws Versus Traditional Pedicle Screws in Moving Lumbar Fusions From Hospitals to Outpatient Surgery Centers

Scientific Paper

Chin KR1, Pencle FJRCoombs AVElsharkawy MPacker CFHothem EASeale JA.

Interested medical professionals can read through the full paper, also published in Clinical Spine Surgery, here.


Level III.


To report on the outcomes of midline cortical bone trajectory (CBT) pedicle screw surgical technique for posterior lumbar fixation in the outpatient surgery center (OSC) compared with traditional pedicle screws in the hospital.


Traditional pedicle screws have been the gold standard for posterior lumbar fusion. Advances in spine surgery, including less invasive procedures have propelled the design of instruments and implants to achieve greater posterior spinal fixation, with decreased tissue destruction and higher safety margins. Biomechanical studies have validated the superior pullout strength of cortical screws versus the traditional pedicle screws and represent an opportunity to perform safe lumbar fusions in OSCs with same day discharge.


The medical records of 60 patients with prospectively collected data were reviewed. Two matched cohort groups consisting of 30 patients each, CBT pedicle screws performed in OSC patients (group 1) was compared with traditional pedicle screws performed in hospital patients (group 2). Outcomes were assessed with self-reported Visual Analog Scale (VAS) scores, Oswestry Disability Index scores, and radiologic fusion rate.


Totally, 33 males and 27 females, age range (28-75), average 58±3 years. Average body mass index was 29±1.15 kg/m. A total of 65% of surgeries were at L5-S1 level. Significant improvement noted in VAS back pain scores in the OSC group from 7.8±0.5 to 2.5±0.7, P=0.001. Comparing intergroup VAS back pain scores and Oswestry Disability Index scores, OSC group demonstrated significant improvement, P=0.004 and 0.027, respectively. Fusion rate at 2 years was similar, P=0.855 between groups.


We successfully transitioned our lumbar fusions from hospitals to OSCs using a midline CBT pedicle screw technique. Although traditional pedicle screw placement is effective and may be viable in an OSC, we see more advantages to use midline cortical screws over traditional pedicle screws.



Dr. Kingsley R. Chin is a board-certified Harvard-trained Orthopedic Spine Surgeon and Professor with copious business and information technology exposure. He sees a niche opportunity where medicine, business and info. tech meet – and is uniquely educated at the intersection of these three professions. He has experience as Professor of Clinical Biomedical Sciences & Admissions Committee Member at the Charles E. Schmidt College of Medicine at Florida Atlantic University, Professor of Clinical Orthopedic Surgery at the Herbert Wertheim College of Medicine at Florida International University, Assistant Professor of Orthopaedics at the University of Pennsylvania Medical School, Visiting Spine Surgeon & Professor at the University of the West Indies, Mona, and Adjunct Professor of Clinical Biomedical Sciences at the University of Technology, Jamaica.

Learn more about Dr. Chin here and connect via LinkedIn.


Less Exposure Surgery (LES) is based on a new philosophy of performing surgery, leading the charge to prove through bench and clinical outcomes research that LES treatment options are the best solutions – to lowering the cost of healthcare, improving outcomes and increasing patient satisfaction. Learn more at LESSociety.org.

The LES Society philosophy: “Tailor treatment to the individual aiding in the quickest recovery and return to a pain-free lifestyle, using LES® techniques that lessen exposure, preserve unoffending anatomy and utilize new technologies which are safe, easy to adopt and reproducible. These LES®techniques lessen blood loss, surgical time and exposure to radiation and can be safely performed in an outpatient center. Less is more.” – Kingsley R. Chin, MD


The LESS Institute is the world leader center of excellence in Less Exposure Surgery. Our safe, effective outpatient treatments help patients recover quickly, avoid expensive hospital stays and return home to their family the same day. Watch our patient stories, follow us on Facebook and visit TheLESSInstitute.com to learn more.


The above study utilized LES Technology from SpineFrontier – leading provider of LES Technologies and instruments – offering surgeons and patients superior technology and services.



Chin KR1, Pencle FJRCoombs AVElsharkawy MPacker CFHothem EASeale JA.

Author information

  1. *Herbert Wertheim College of Medicine at Florida International University †Charles E. Schmidt College of Medicine at Florida Atlantic University, Miami ‡Less Exposure Surgery Specialists Institute (LESS Institute) §Less Exposure Surgery (LES) Society, Fort Lauderdale, FL.
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