Risk factor analysis of postoperative kyphotic change in subaxial cervical alignment after upper cervical fixation

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Little is known about the risk factors for postoperative subaxial cervical kyphosis following craniovertebral junction (CVJ) fixation. The object of this study was to evaluate postoperative changes in cervical alignment and to identify the risk factors for postoperative kyphotic change in the subaxial cervical spine after CVJ fixation.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>One hundred fifteen patients were retrospectively analyzed for postoperative subaxial kyphosis after CVJ fixation. Relations between subaxial kyphosis and radiological risk factors, including segmental angles and ranges of motion (ROMs) at C0–1, C1–2, and C2–7, and clinical factors, such as age, sex, etiology, occipital fixation, extensor muscle resection at C2, additional C1–2 posterior wiring, and subaxial laminoplasty, were investigated. Univariate and multivariate logistic regression analyses were conducted to identify the risk factors for postoperative kyphotic changes in the subaxial cervical spine.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>The C2–7 angle change was more than −10° in 30 (26.1%) of the 115 patients. Risk factor analysis showed CVJ fixation combined with subaxial laminoplasty (OR 9.336, 95% CI 1.484–58.734, p = 0.017) and a small ROM at the C0–1 segment (OR 0.836, 95% CI 0.757–0.923, p &lt; 0.01) were related to postoperative subaxial kyphotic change. On the other hand, age, sex, resection of the C2 extensor muscle, rheumatoid arthritis, additional C1–2 posterior wiring, and postoperative segmental angles were not risk factors for postoperative subaxial kyphosis</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>Subaxial alignment change is not uncommon after CVJ fixation. Muscle detachment at the C2 spinous process was not a risk factor of kyphotic change. The study findings suggest that a small ROM at the C0–1 segment with or without occipital fixation and combined subaxial laminoplasty are risk factors for subaxial kyphotic change.</jats:p></jats:sec>

Evaluation and Surgical Planning for Craniovertebral Junction Deformity

“…Interestingly, extensor muscle detachment at C2 itself was not identified as a risk factor of kyphotic change, but when combined with subaxial laminoplasty and wider dissection of deep extensor muscle, the risk of subaxial kyphotic change was significantly increased. 59 These results suggest the C0-1 segment is the dominant segment for compensating for abnormal angulation of the subaxial cervical spine after upper cervical fixation. These results imply it is important not to include occipital fixation during upper cervical fixation to avoid loss of subaxial cervical lordosis and preserve C0-1 segmental motion.…”

“…Furthermore, the study suggested a small ROM of the C0–1 segment with or without occipital fixation and combined subaxial laminoplasty independently predict subaxial kyphotic change after upper cervical fixation. Interestingly, extensor muscle detachment at C2 itself was not identified as a risk factor of kyphotic change, but when combined with subaxial laminoplasty and wider dissection of deep extensor muscle, the risk of subaxial kyphotic change was significantly increased [ 59 ].…”

Posterior hybrid surgery for atlantoaxial dislocation coexisting with multilevel cervical spondylotic myelopathy

“…Gong et al ( 4) indicated that atlanto-occipital joint flexion stiffness was closely correlated with a high risk for the occurrence of cervical spondylosis. Kim et al (11) proved that a small ROM at C0-1 combined subaxial laminoplasty is a risk factor for subaxial kyphotic change. The cervical canal further decreases owing to the presence of craniovertebral lesions (12).…”

SOF System; A New Nomenclature System for the Surgical Techniques of Cervical Spine Deformity

“…However, surgical correction of CSD can be challenging not only because it often requires osteotomies to obtain adequate correction especially in the setting of rigid CSD, but also because the target of surgical correction is adjacent to the critical neurovascular structures. 8,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] Thus, the postoperative complications have been reported to be relatively high and the number of studies on CSD are far inferior to those of thoracolumbar deformity.…”