Changes in the Iliac Crest-Lumbar Relationship from Standing to Prone

Dr. Kingsley R. Chin of the Less Institute medical research

Scientific Paper

Chin KR1Kuntz AFBohlman HHEmery SE.

Interested medical professionals can read through the full paper, as published in the Spine Journal, here.

Background Context

It is known that positioning patients on the Jackson and Andrews operative tables causes changes in lumbar lordosis and pelvic rotation. However, it is unknown if the relationship between the iliac crest and underlying lumbar levels, in particular the L4-L5 interspace, changes from standing to prone on these tables.


To assess the changes in the relationship between the iliac crests and lumbar spinal levels from standing to prone on two different operative positions using the Jackson and Andrews frames.

Study Design/Setting

Comparative analysis of iliac crest position relative to spinal levels in the preoperative standing position and while positioned on the Jackson and Andrews frames.

Patient Sample

48 randomly selected patients who underwent spinal surgery on either the Jackson or Andrews frame.

Outcome Measures



Comparative measurements were made of the preoperative and intraoperative plain lateral lumbar radiographs. The location of the superior border of the iliac crest relative to the L4 lumbar spine level was compared between radiographs.


Preoperatively, the iliac crest aligned with L4/L4-L5 spinal level in 79.2% of the 48 patients compared with 85.5% of intraoperative cases (p=.59). Intraoperative iliac crest level aligned with the L4/L4-L5 level in 80.8% and 90.9% of the patients on the Andrews and Jackson tables respectively (p=.43). Thirty-four patients (70.8%) demonstrated no change in iliac crest alignment between intraoperative and preoperative radiographs. There was a trend for the iliac crest to shift cephalad with operative positioning.


Approximately 30% of patients demonstrated changes in the relationship between the iliac crest and lumbar levels between standing and positioning prone. The intraoperative position of the iliac crest aligned more accurately with the L4/L4-L5 spine level on the Jackson and Andrews frame compared with preoperative standing radiographs respectively. Further biomechanical studies should investigate the implication for lumbopelvic fixation.

About Author Orthopedic Surgeon Dr. Kingsley R. Chin

Misaligned Versus Straight Placement of Anterior Cervical Plates: A Clinical and Radiologic Outcomes Study, JAAOS, Dr. Kingsley R. Chin
Dr. Kingsley R. Chin, Founder of philosophy and practice of The LES Society and The LESS Institute

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 Studies at the University of Technology, Jamaica.

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

About Less Exposure Surgery

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

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

About The LESS Institute

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 to learn more.

About SpineFrontier

The above study utilized Less Exposure Surgery by SpineFrontier – leading provider of LES Technologies and instruments – offering surgeons and patients superior technology and services.

Scientific Paper Author & Citation Details


Chin KR1Kuntz AFBohlman HHEmery SE.

Author information

  1. Division of Spine Surgery, Department of Orthopaedics, University of Pennsylvania School of Medicine, 3400 Spruce Street, Philadelphia, 19104, USA.

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