[Fractures of the dens in patients older than 65 years: direct osteosynthesis of the dens versus C1-C2 posterior fixation].

PURPOSE OF THE STUDY: Surgical treatment is preferred in our department in all patients with type II and type III dens fractures, regardless of their age, with the exception of non-displaced or completely reduced fractures in young patients. The aim of this study was to evaluate patients over 65 years of age treated by direct osteosynthesis of the dens or posterior atlanto-axial fixation and spondylodesis.

MATERIAL: In the years 2001 to 2005, 28 patients aged 65 years and older were surgically treated for dens fracture. This included 13 men and 15 women between 65 and 90 years of age, with an average of 77.4 years. According to the treatment, i.e., direct dens osteosynthesis (1) or C1-C2 posterior fixation (2), two groups were evaluated, and two categories were considered by age, i.e., 65 to 74 years (8 patients) and 75 years and older (20 patients). In 23 patients, an isolated fracture of the dens was present and, in five patients, injury was part of a complex C1-C2 fracture. A Frankel grade D neurological deficit was found in three patients.

METHODS: In all patients, surgical treatment by direct osteosynthesis of the dens from the anterior approach, using two cannulated screws, was preferred as the method of choice. However, in the case of distinct osteoporosis, fragmented fracture of the dens base or tear of the ligamentum transversum atlantis, we used the Harms method of posterior fusion with polyaxial screw fixation as the primary treatment, or the Magerl transarticular fixation completed with the Gallie technique from the dorsal approach. The patients were followed up at 3, 6 and 12 weeks, at 6 and 12 months, and then at one-year intervals. X-ray and clinical examinations were made at the regular follow-ups and functional radiographs were taken at 12 months following the surgery. The whole group was evaluated in the range of 18 to 84 months (average, 37.3 months). Neurological deficit was assessed on the basis of the Frankel classification. The results were analysed using the Chi-square test.

RESULTS: Of 20 patients still living at the time of this evaluation, 11 underwent direct osteosynthesis and nine were treated by posterior instrumented spondylodesis. In group 1, pseudoarthrosis of the dens or fibrous callus developed in one patient (9.1 %) and a line of fracture was evident in one patient of group 2 (11.1 %), which was not significant (p<0.05). However, a statistically significant difference in mortality was found when the two age categories were compared (p>0.05), with 0 % in the younger and 40 % in the older category. The overall mortality within 6 weeks of injury was 28.6 %. Mortality in group 1 and group 2 was 21.4 % and 35.7 %, respectively; this difference was not statistically significant (p<0.05).

DISCUSSION: We use conservative treatment only in the patients who are able to stand up and move soon after injury. If this is not feasible, we prefer surgical treatment with the same aim achieved as soon as possible without rigid external fixation. In this study, surgery was associated with an acceptable number of minor complications due to poor bone quality or health state of the patient. The higher mortality in the higher age category was obviously related to generally poorer health of these patients.

CONCLUSION: Surgical treatment can significantly improve the quality of life in elderly patients who have suffered a fracture of the dens. The surgical technique should be chosen to take bone quality, degenerative changes of the spine and overall health of the patient into consideration. Mortality after surgery is not related to the technique selected but to patient's age. Elderly patients with neurological deficit usually die due to co-morbidity, regardless of the therapy used.