94 - Vertebral Artery Variation and Imposed Risks Associated with Anterior Cervical Discectomy and Fusion Procedures – a Case Study with Surgeons’ Perspectives

Poster Board Number: 94
There are separate poster presentation times for odd and even posters.
Odd poster #s – first hour
Even poster #s – second hour

Co-authors:

Robert Ryu - Orthopedic One; Jodie Foster - Ohio University Heritage College of Osteopathic Medicine; Caroline Gundler - Ohio University Heritage College of Osteopathic Medicine

Abstract Body : Introduction and Objective:




Anterior cervical discectomy and fusion (ACDF) is a common procedure in the US. Although this is a relatively safe procedure, one dangerous sequela of ACDF is the risk of vertebral artery (VA) laceration. While rare, it is crucial for surgeons to prevent this potentially deadly complication through knowledge of VA anatomy. Typically, the VA is protected in the transverse foreman, but anomalies of this artery exist, and the artery can be found more medial or proximal in the surgical site than expected. The purpose of this article is to report an anomaly found in a cadaveric specimen and its importance in surgical planning.









Materials and Methods:




A cadaveric donor from Ohio University’s whole body donation program with a VA anomaly was dissected to expose the VA in its entirety. Data obtained included: vertebral level of origin, artery origin, vertebral entrance level, and demographic data. After photographs and detailed measurements were taken, the case was analyzed by two orthopedic surgeons who documented their typical protocol for the procedure; VA examination prior to the procedure; and rarity of this specific cadaveric case.









Results:




The donor was a 66-year-old male who had an ACDF procedure spanning vertebral levels C4-C7. The LVA originated from the subclavian artery before tracking medially and entering the transverse foramen at C5, a high entrance. Anterior tubercles at the levels of C5/C6 were absent with noticeable osteophytes contralaterally. The LVA travelled within 2mm of the ACDF plate. The orthopedic surgeons noted that removal of anterior tubercles is rare during this procedure and preoperative imaging using MRI are studied to prevent VA injury. If concern of variants arises, additional imaging through a CT angiography (CTA) or magnetic resonance angiography (MRA) are obtained.









Conclusion:




There are no studies published on the anatomy of VA variants and their implications on ACDF procedures. ACDF was found to have complication rates in 13.2% of cases. VA variants are observed in up to 20% of the U.S. population and VA injury in ACDF procedures has a rate near 0.5%. With anatomic variations leading to a higher risk of injury, surgeons are required to take further precautionary steps prior to operating including ordering CTA/MRA films. Understanding the detailed anatomy of the VA and its variants is critical.









Significance/Implication:




A better understanding of the VA and its anatomical variance can lead to better outcomes in health care. Overall incidence rates of VA injury increase with variants and supports the need for extensive pre-operative imaging. This study demonstrates a clinical example and real-world application on the importance of understanding VA variation with expert surgical perspectives.