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The Mandibular Angle as a Landmark for Identification of Cervical Spinal Level

Scientific Paper

Auerbach JD1, Weidner ZPill SGMehta SChin KR.

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


Retrospective radiographic review.


To determine the utility of the mandibular angle as a landmark for identification of cervical spinal level.


Improper localization of the skin incision during anterior cervical spine surgery may lead to increased technical difficulty of the surgery. Although the use of traditional palpable anterior neck landmarks (hyoid bone, cricoid cartilage, thyroid cartilage, and carotid tubercle) help identify appropriate spinal levels, their reliability has not been validated in actual surgeries. We hypothesize that the angle of the mandible (AM) is a consistently palpable landmark, and that the mandible can be used to accurately template the distance to subaxial cervical levels using preoperative radiographs.


As a pilot study, we prospectively evaluated 30 consecutive patients who underwent anterior cervical diskectomy and fusion to assess the interobserver accuracy of palpating the mandibular angle, hyoid, carotid tubercle, and thyroid and cricoid cartilages. In a second set of 26 consecutive patients undergoing anterior cervical diskectomy and fusion, we then retrospectively reviewed standing preoperative lateral plain radiographs of the cervical spine, in addition to supine lateral cervical spine radiographs taken at the time of surgery, to assess: (1) the position of the AM relative to the corresponding cervical spinal level, and (2) whether or not the position of the AM relative to the subaxial cervical levels is different on preoperative standing films and intraoperative supine films. In these same 26 patients, we also measured the vertical distance between the AM and the location of each subaxial intervertebral disc space. These measurements were repeated for the hyoid bone as a control for each patient.


The interobserver accuracy was 100% between observers for identifying the AM, hyoid bone, thyroid cartilage, and cricothyroid membrane, and 93% for carotid tubercle. The frequency with which anterior neck landmarks were palpable by the surgeon and assisting senior residents was as follows: AM (100%), hyoid bone (83%), thyroid cartilage and cricothyroid membrane (93%), and carotid tubercle (Surgeon: 63%, Resident: 57%, P = 0.79). There was 100% correlation between the position of the mandibular angle in the preoperative standing lateral radiograph and the intraoperative supine lateral radiograph, compared with 65% with the hyoid bone. The distances between the AM or hyoid to each disc space did not vary significantly between preoperative and intraoperative radiographs (P > 0.05).


The mandibular angle was shown to be the most consistently palpable landmark. Further, the distance from the mandible, measured on preoperative plain lateral cervical spine radiographs, is an accurate template to determine cervical spine levels during anterior cervical spine surgery.


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.


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.



Auerbach JD1, Weidner ZPill SGMehta SChin KR..

Author information

  1. Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA. [email protected]

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