Technique tips and retrospective review of prospectively collected data.
To describe a technique for centralizing cervical plates using the center of the manubrium as a primary external guide and its alignment with the mandible as a secondary guide.
Proper alignment of cervical plates is desirable to avoid improper placement of screws and possibly altered biomechanical performance. Large body habitus may portend suboptimal exposure, a limited utility of skin surface landmarks for level determination, and may make it difficult to reliably centralize plates in the coronal plane during anterior cervical surgery.
We describe a technique that uses the center of the manubrium to determine the midline of the cervical spine and align a line drawn through the manubrium with the center of the mandible to provide a central axis for placing cervical plates along the entire cervical spine. We used anteroposterior fluoroscopy to validate that a line from the middle of the manubrium to the mandible bisected the spinous processes and midline of the vertebral bodies. We prospectively collected data on 39 consecutive patients undergoing anterior cervical discectomy and fusion with cervical plates using this technique.
The mean amount of angulation and translation about a midline axis were 2.24° ± 1.49° and 1.04 ± 0.86 mm, respectively. There were no statistical differences among 1-level, 2-level, and 3-level fusions (P > 0.05). The intraobserver correlation coefficient for the measurement technique was R = 0.90 (P = 0.0016).
We validated that the midline of the cervical spine is in line with a straight bovie cord connecting the midline of the manubrium to the midline of the mandible using anteroposterior fluoroscopy. Using this line, we prospectively centered cervical plates with no significant difference between levels. These data may also serve as a benchmark for assessing cervical plate alignment.
We prospectively assessed the technique of using the center of the manubrium to centralize cervical plates in 39 consecutive patients undergoing anterior cervical discectomy and fusion. We also used anteroposterior fluoroscopy to validate that a line from the middle of the manubrium to the mandible bisected the spinous processes and midline of the vertebral bodies.
From the *The Institute for Minimally Invasive Spine Surgery (iMIS), Palm Beach, FL; †Department of Orthopaedic Surgery, The University of Pennsylvania, Philadelphia, PA; and ‡The Department of Orthopaedic Surgery, Monmouth Medical Center, Long Branch, NJ.
Acknowledgment date: April 7, 2008. Revision date: December 8, 2008. Acceptance date: December 15, 2008.
The device(s)/drug(s) is/are FDA-approved or approved by corresponding national agency for this indication. No funds were received in support of this work.
No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Address correspondence and reprint requests to Kingsley R. Chin, MD, Institute for Minimally Invasive Spine Surgery, PO Box 567, Palm Beach, FL 33480; E-mail: kingsleychin@iMISsurgery.com