Abstract
Purpose
In stabilisations of atlantoaxial instabilities it holds risks to injure the A. vertebralis as well as neurological structures. Furthermore the posterior approach of the upper part of the cervical spine requires a huge and traumatic preparation of the soft tissue. However the anterior transarticular C1-2 fusion (ATF) is less traumatic and offers almost the same strengh of the stabilisation.
Methods
Since the 01/2007 22 multimorbid patients with atlanto-axial instabilities of different entities were treated via the ATF, were regular examined radiologicaly (x-ray/CT) and the procedure critically judged.
Results
C1-2 fusions were performed in 22 patients (17f, 5m, Ø 81,67 years). Main symptoms was pain radiating in the upper cervical spine and the occiput, 2 Patients complaining radiating pain with paraesthesia. The average operation-time took 64,5 min. Leftside the screws of Ø 39,5mm (32–44mm), rightside of 36mm (32–44mm) were inserted in addiction to the point of access and the angle of insertion (mediolateral angle Ø 32,0°, ventrodorsal Ø17,6°). No introperative complications occured, one revision had to be done because of p.o. bleeding, one because of screw dislocation. Postoperative x-ray and CT control of the upper cervical spine showed 30/44 screws in 22 patients in correct position. 8 (18,2%) screws were too long, 3 (6,8%) screws were placed too anterior and 3 (6,8%) too medial. 8 additional positionated dens-screws were in correct position. After a clear learning curve both screws of the 6th patient were positoinated correct. Two aspects are important for success: Correct entry point and right insertion of the angle in the coronar and sagittal view. A low intraoperative blood loss, a non traumatic access as well as an immediate pain decrease have to be valued positively for this procedure.
Conclusions
The gentle procedure of the ATF requires-despite of the huge experience in anterior surgery of dens fractures - a learning curve, because of the more proximate insertion point, the flat insertion angle and the closeness of the A. vertebralis. If these aspects are going to be noticed, failed screw positioning and excessive length as well as injuries of the A. vertebralis can be avoided.
