[Magerls technique of c1-2 fixation.].

Magerl technique of transarticular fixation of C1-2 by screws is one of the possibilities of the antlantoaxial fusion. For the first time it was published by Magerl and Seemann in 1987 but the first author had been performing it already since 1979. The principle of the method consists in the placement of two screws from the dorsal approach through atlantoaxial joints in the sagittal plane. The main indication for the Magerl's C1-2 fixation is an acute or chronic instability and a painful osteoarthritis of atlantoaxial joints. Contraindicated is this method only in massive destruction of the lateral mass of atlas and in an anomalous course of the vertebral artery. The authors present their own experience with the first 12 patients who they operated on in the period of 1996-1999. In all cases they added dorsal fixation after Gallie (10 patients) or modified after Brooks and Jenkins (2 patients). The group consisted only of patients with a separate atlantoaxial fusion, i. e. not with the transarticular fixation by screws as part of the set of instruments for occipitocervical fusion. Final check of all patients was performed at the interval of 9-48 months after the operation, on average 19 months. The final outcome was evaluated subjectively according to the patients and also objectively. Subjectively, the patients complained at the beginning of the pain in the region of the wound after the bone graft harvesting which was as a rule greater than the pain in the region of the cervical spine. The pain subsided in 6 weeks, at the latest. All patients but for one (malum suboccipitale Rusti) were satisfied, i. e. they would undergo the operation again. Objectively all 24 screws were inserted correctly thrugh the antlantoaxial joint. Two screws were driven asymmetrically, one of the obliquely medially and the other obliquely laterally without a clinical impact. One screw was evaluated by authors as extending too anteriorly, also without a clinical impact. After 12-14 weeks the functional radiographs showed a good fusion of the C1 -2 segment in 11 (91,7 %) out of 12 patients. Neither an injury of the nerve structures nor of the vertebral artery was recorded within peroperative complications. Loosening or breakage of screws or elements of the dorsal fixation were not recorded, either. The results of the work prove that the Magerls technique of atlantoaxial fusion is effective and in the hands of a specialist also a safe method which provides multiple opportunities for the treatment of C1-2 instabilities. Key words: atlantoaxial instability, fusion, Magerls C1-2 fixation.