General Session: Cervical Degenerative - Hall F
Presented by: D. Kitumba
D. Kitumba(1,2), R. Reinas(1), O. Alves(1)
(1) Centro Hospitalar Vila Nova de Gaia, Neurocirurgia, Vila Nova de Gaia, Portugal
(2) Faculdade de Medicina da Universidade Agostinho Neto, Luanda, Angola
Summary: Few studies evaluate the impact of fixations surgery around C0-C1-C2 on overall cervical alignment.
Objective: To analyse the influence that C0-C1-C2 fixations has on segmental (C0-C1-C2) and global cervical (C2-C7) alignment.
Methods: We retrospectively evaluated patients with high cervical spine instability that underwent C0-C2 or C1-C2 posterior fixations. Data were collected from pre and postoperatively plane radiographic exams on neutral position at last follow-up. The primary radiological outcomes were: C0-C1 angle, C1-C2 angle, C0-C2 angle, C2-C7 angle, cervical sagittal vertical alignment (cSVA) and T1 slope, all parameters measured using Sectra Corporation Software.
Results: Sixteen (16) consecutive patients were included with a mean age of 60,7 years (range 24 - 80 years), 10 females and 5 males. All patients were affected by atlanto-axial instability principally due to congenital malformation (62,6%) or degenerative disease (24,8%). Nine patients (60%) underwent C0-C2 fixation and six (40%) C1-2 fixation, and a mean follow up of 21,46 months were accomplished. C1-C2 fixations resulted on an increase of C1-C2 angle (mean increase 10,3º; range -13º to 24,2º) and a slight decrease of the C0-C1 angle (mean -4,5º; ranging from -24,5º to 17,3º). In contrast, C0-C2 fixation caused minimal impact on both C0-C1 angle (mean -0,33º; range -8,80º to 16,40º) and C1-C2 angle (mean -0,30º; range -9,60º to 7,10º). Focusing on subaxial sagittal alignment, C1-C2 and C0-C2 fixations showed no difference on C2-C7 angle (mean -4,08º versus -5,29º, respectively) and on T1-Slope (mean -4,03 versus mean -2,44), while affecting differently cSVA (means 11,01mm versus - 2,15mm).
Conclusions: Regarding the functional unit C0-C2, only C1-C2 fixation impacts on segmental C0-C2 angle due almost exclusively to a lordotic change in C1-C2 angle. As for C2-C7 both induce slight compensatory kyphotic curvature. The most distinctive feature between the two types of operation is a change in the cSVA: C0-C2 tends to increase it whereas C1-C2 fixation has only a minimal effect. Pre-operative cSVA should be taken into account when choosing the most appropriate fixation option.
Keywords: C0-C2 fixation; C1-C2 fixation; subaxial sagittal alignment.