Optimizing Alignment Parameters During Craniocervical Stabilization and Fusion: A Technical Note

Abstract

Proper craniocervical alignment during craniocervical reduction, stabilization, and fusion optimizes cerebrospinal fluid (CSF) flow through the foramen magnum, establishes the appropriate "gaze angle", avoids dysphagia and dyspnea, and, most importantly, normalizes the clival-axial angle (CXA) to reduce ventral brainstem compression. To illustrate the metrics of reduction that include CXA, posterior occipital cervical angle, orbital-axial or "gaze angle", and mandible-axial angle, we present a video illustration of a patient presenting with signs and symptoms of the cervical medullary syndrome along with concordant radiographic findings of craniocervical instability as identified on dynamic imaging and through assessment of the CXA, Harris, and Grabb-Oakes measurements.

Reference values of four measures of craniocervical stability using upright dynamic magnetic resonance imaging

“…That is, was there a significant difference between the extent of motion measured between the neutral and maximal flexion positions, and the neutral and maximal extension positions? We set Increase in BAI suggests anterior translation of the cranium relative to the axis [29,30]. The posterior axial line is drawn through the posteroinferior and the posterior most margins of the vertebral body of C2, regardless of the orientation of the posterosuperior aspect of the odontoid.…”

“…Visual inspection of the participants' measures on the BAI, BAA, BDI and GOL in each of the three sagittal cervical positions was undertaken. To determine the proportion of false-positive identification of radiological evidence of CCI in our cohort, traditional cutoff criteria for normality were used based on previous studies [29,30].…”

Cervicogenic Dizziness Associated With Craniocervical Instability: A Case Report

“…An acute CXA of less than 150° or being deformed like this case can be a source of ventral brainstem compression. Normalizing the CXA to reduce ventral brainstem compression is of paramount importance [ 10 ]. Although surgery is the direct procedure for removing neural compression, conservative strategy is the mainstay of initial care for patients with small amounts of CCI [ 11 ].…”

The Neurosurgical Intraoperative Checklist for Surgery of the Craniocervical Junction and Spine

“…The checklist comprises the following questions (see also Figure 1 The checklist prompted attention to positioning and both the coronal and sagittal alignment of hardware. Prior to locking down the hardware, we repositioned the Mayfield head holder to optimize craniocervical parameters as previously described and to lessen or eliminate kyphosis, tilt, or rotation [6,7]. Careful attention to the fluoro-CT images minimized the likelihood of screw misplacement, particularly at C1, C2, C7, and T1.…”