The optimal treatment of Type II fracture remains controversial.9,10 Each treatment option for Type II odontoid fracture has advantages and disadvantages.25Although High nonunion rate associated with external fixation have been reported,18−22surgical treatment of type 2 odontoid fracture is associated with morbidity and mortality rates between 2% and 4%. Specific complications for posterior approach include: vertebral artery injury and new onset neurological deficits. In this case report vascular injury was highly considered as higher risk due to possibility of vascular anomalies, although CT angiography was not done. C1 to C2 fusion also causes the loss of atlantoaxial movement, rendering the patient unable to rotate his or her head. Surgical interventions such as anterior odontoid screw fixation can preserve atlantoaxial motion, but it is technically demanding and may encountered with failure despite healing rate of 90% for type II fractures.28,29 The major complications of this approach are neural or vessel injury, esophageal and pharyngeal perforation, and airway obstruction. The vulnerable structures include the glossopharyngeal and hypoglossal nerves32. Regarding conservative management, among external fixation techniques, the halo-vest provides the greatest neck immobilization as compared with other orthoses and there is no biomechanical differences between variant types of halo vest 26,27.
To date, no study evaluate treatment of displaced type 2 odontoid fracture with proximal cervical anomalies. Although Clark and White30 documented a 68% healing rate and mean period for bone healing was 20.2 weeks for type 2 dens fracture treated by halo vest. In this case report the odontoid fracture was healed after 8 weeks, however we cannot compare two result as it was one case and there are a lot of confounding factors not analyzed in this case report which include: patient age > 40 years, fracture displacements > 5 mm, posteriorly displaced fractures > anterior displaced fractures, osteoporosis and in patients with neurological deficits.35. In this case report odontoid fracture was healed with 100 anterior angulation that may be due to frequent adjustment of non-invasive halo vest to allow dressing for pressure ulcer and reliving the patient stretching discomfort. The patient cervical ROM (flexion 45o, extension 70o, right and left rotation 70o, right and left lateral flexion 40o) was achieved during the last follow up, despite initial limitation which was present after immediate removal of noninvasive halo. ROM limitation may be due to stiffness of neck muscles after a long period of immobilization. However ROM was found to be improved during the last follow up. Conservative treatment was found to be superior to surgical fusion of C1-C2 head in terms of preserving movement of cervical rotation. Anterior odontoid screw could be inserted in order to preserve atlanto-axial motion, however in our case this technique was not possible to be performed due to congenital anatomical distortion of dens axis which almost need vertical inclination for trajectory of anterior screw. Using of Noninvasive halo in treatment of displaced odontoid fracture is more cost effective than surgery and invasive halo vest, as there is a significant difference in cost the price of the noninvasive halo is less than 40% that of invasive halo vest36.
In this case report the Patient had transient facial edema subsided by day 4, pressure ulcer which was responded to dressing, self-hygiene and chewing hard food difficulties. Also the patient was complaining of discomfort over all 8 weeks period. On the other hand complications of invasive halo vest immobilization are patient discomfort33 pin-site infection, osteomyelitis, nerve injury, Dural penetration and CSF leakage, intracranial abscesses, dysphagia, pin-site scar formation, restriction of respiratory function, and loss of reduction.19,33,34.
Limitation:
Study design was retrospective case report and Short term follow up. It was evaluated only anterior displacement of type 2 odontoid fracture.