Type II odontoid fracture in elderly patients treated conservatively: is fracture healing the goal?

Purpose: Analysis of functional outcome of elderly patients with type II odontoid fractures treated conservatively in relation to their radiological outcome. Methods: A total of 50 geriatric patients with type II odontoid fractures were treated with Aspen/Vista collars. On admission, each patient was assessed assigning ASA score, modified Rankin Scale (mRS-pre) and Charlson Comorbidity Index (CCI). From 12–15 months after treatment, functional evaluations were performed employing a second modified Rankin Scale (mRS-post) together with Neck Disability Index (NDI) and Smiley-Webster pain scale (SWPS). Radiological outcome was evaluated through dynamic cervical spine X-rays at 3 months and cervical spine CT scans 6 months after treatment. Three different conditions were identified: stable union, stable non-union and unstable non-union. Surgery was preferred whenever a fracture gap > 2 mm, an antero-posterior displacement > 5 mm, an odontoid angulation > 11° or neurological deficits occurred. Results: Among the 50 patients, 24 reached a stable union, while 26 a stable non-union. Comparing the two groups, no differences in ASA (p = 0.60), CCI (p = 0.85) and mRS-pre (p = 0.14) were noted. Similarly, no differences in mRS-post (p = 0.96), SWPS (p = 0.85) and NDI (p = 0.51) were observed between patients who reached an osseous fusion and those with a stable fibrous non-union. No effects of age, sex, ASA, mRS-pre, fracture dislocation and radiological outcome were discovered on functional outcome. At logistic regression analysis, female sex and high values of CCI emerged associated with worse NDI. Conclusions: In geriatric type II odontoid fractures, pre-injury clinical status and comorbidities overcome imaging in determining post-treatment level of function. Hard collar immobilization led to a favourable functional outcome with mRS-post, NDI and SWPS values diffusely encouraging whatever a bony union or a fibrous non-union was obtained.