Management of fresh odontoid fractures using posterior C1–2 fixation without fusion: a long-term clinical follow-up study

OBJECTIVE Posterior C1–2 fixation without fusion makes it possible to restore atlantoaxial motion after removing the implant, and it has been used as an alternative technique for odontoid fractures; however, the long-term efficacy of this technique remains uncertain. The purpose of the present study was to explore the long-term follow-up outcomes of patients with odontoid fractures who underwent posterior C1–2 fixation without fusion. METHODS A retrospective study was performed on 62 patients with type II/III fresh odontoid fractures who underwent posterior C1–2 fixation without fusion and were followed up for more than 5 years. The patients were divided into group A (23 patients with implant removal) and group B (39 patients without implant removal) based on whether they underwent a second surgery to remove the implant. The clinical outcomes were recorded and compared between the two groups. In group A, the range of motion (ROM) of C1–2 was calculated, and correlation analysis was performed to explore the factors that influence the ROM of C1–2. RESULTS A solid fracture fusion was found in all patients. At the final follow-up, no significant difference was found in visual analog scale score or American Spinal Injury Association Impairment Scale score between the two groups (p > 0.05), but patients in group A had a lower Neck Disability Index score and milder neck stiffness than did patients in group B (p < 0.05). In group A, 87.0% (20/23) of the patients had atlantoodontoid joint osteoarthritis at the final follow-up. In group A, the C1–2 ROM in rotation was 6.1° ± 4.5° at the final follow-up, whereas the C1–2 ROM in flexion-extension was 1.8° ± 1.2°. A negative correlation was found between the C1–2 ROM in rotation and the severity of tissue injury in the atlantoaxial region (r = –0.403, p = 0.024) and the degeneration of the atlantoodontoid joint (r = –0.586, p = 0.001). CONCLUSIONS Posterior C1–2 fixation without fusion can be used effectively for the management of fresh odontoid fractures. The removal of the implant can further improve the clinical efficacy, but satisfactory atlantoaxial motion cannot be maintained for a long time after implant removal. A surgeon should reconsider the contribution of posterior C1–2 fixation without fusion and secondary implant removal in preserving atlantoaxial mobility for patients with fresh odontoid fractures.

Evaluation of external stabilization of type II odontoid fractures in geriatric patients—An experimental study on a newly developed cadaveric trauma model

Background Along with the growing geriatric population, the number of odontoid fractures is steadily increasing. However, the effectiveness of immobilizing geriatric odontoid fractures using a cervical collar has been questioned. The aim of the present study is to analyze the physiological and pathological motion in odontoid fractures and to assess limitation of motion in the cervical spine when applying a cervical collar. Methods Motion analysis was performed with wireless motion tracker on unfixed geriatric human cadavers. First, a new geriatric type II odontoid fracture model was developed. In this model, the type II odontoid fracture is operated via a transoral approach. The physiological and pathological flexion and lateral bending of the cervical spine resulting from this procedure was measured. The resulting motion after external stabilization using a cervical collar was analyzed. Results The new geriatric type II odontoid fracture model was successfully established using seven unfixed human cadavers. The pathological flexion of the cervical spine was significantly increased compared to the physiological flexion (p = 0.027). Furthermore, the flexion was significantly reduced when a cervical collar was applied. In case of flexion the mean remaining motion was significantly reduced (p = 0.0017) from 41° to 14°. For lateral bending the mean remaining motion was significantly reduced (p = 0.0137) from 48° to 18°. Conclusions In case of type II odontoid fracture, flexion and lateral bending of the cervical spine are increased due to spinal instability. Thus, if an odontoid fracture is suspected in geriatric patients, the application of a cervical collar should always be considered since external stabilization can significantly reduce flexion and lateral bending.

Unstable odontoid fractures: technical appraisal of anterior extrapharyangeal open reduction internal fixation for irreducible unstable odontoid fractures. Patient series

BACKGROUND Displaced odontoid fractures that are irreducible with traction and have cervicomedullary compression by the displaced distal fracture fragment or deformity caused by facetal malalignment require early realignment and stabilization. Realignment with ultimate solid fracture fusion and atlantoaxial joint fusion, in some situations, are the aims of surgery. Fifteen such patients were treated with direct anterior extrapharyngeal open reduction and realignment of displaced fracture fragments with realignment of the atlantoaxial facets, followed by a variable screw placement (VSP) plate in compression mode across the fracture or anterior atlantoaxial fixation (transarticular screws or atlantoaxial plate screw construct) or both. OBSERVATIONS Anatomical realignment with rigid fixation was achieved in all patients. Fracture fusion without implant failure was observed in 100% of the patients at 6 months, with 1 unrelated mortality. Minimum follow-up has been 6 months in 14 patients and a maximum of 3 years in 4 patients, with 1 unrelated mortality. LESSONS Most irreducible unstable odontoid fractures can be anatomically realigned by anterior extrapharyngeal approach by facet joint manipulation. Plate (VSP) and screws permit rigid fixation in compression mode with 100% fusion. Any associated atlantoaxial instability can be treated from the same exposure.

Robot-assisted Anterior Odontoid Screw for the Treatment of Type Ⅱ Odontoid Fractures: Safety and Effectiveness Analysis

Background: Anterior odontoid screw fixation is considered to be preferred surgical treatment for the type Ⅱ odontoid fractures. However, due to the high difficulty to insert odontoid screw with barehand, the high risk of screw misalignment and damage to surrounding important tissue structures, we urgently need robot-assisted screw insert navigation technology to improve the safety and accuracy of inserting odontoid screws.Methods: We retrospectively analyzed 7 patients with type II odontoid fractures who underwent Tinavi robot-assisted screw insert technology from May 2018 to May 2019 at our hospital. All patients had received 64-row CT scans and 3D reconstructions completed preoperatively, and magnetic resonance (MRI) were performed to verify the severity of odontoid fractures, soft tissue injuries and vertebral artery height. Postoperative CT was repeated in 6 months after surgery to evaluate cervical stability and confirm whether the screw had breached the bone cortex, the accuracy of screw placement based on Rampersaud A-D grade. Functional recovery was assessed using the post-traumatic Mayor scoring system for the cervical spine.Results: All 7 patients successfully completed the robot-assisted operation without nerve and blood vessel damage. What is the operation time 103.3 minutes, intraoperative blood loss 11.1 ml. The angulation and displacement of the fracture were basically corrected by closed reduction during the operation. Postoperative CT of these 7 patients showed that the cervical spine was stable, the accuracy of “perfect” and “clinically acceptable” odontoid screw implantation was 100% (7/7), none of the seven odontoid screws breached the bone cortex. Reexamination of X-rays showed that the fractures were all healed, and the average fracture healing time was average 13.7weeks (12-15weeks). During the follow-up period, 7 patients had no surgical complications, postoperative cervical spine trauma mayo score: excellent in 6 cases and good in 1 case. Conclusion: Tinavi robot-assisted screw insert technology is a minimally invasive, accurate, safe and feasible method for the treatment of type Ⅱ odontoid fractures.

Morphometric parameters of the odontoid process of C2 vertebrae, in Indian population, a CT evaluation

Background: Osteosynthesis of odontoid fractures, especially for type II odontoid fractures, is often achieved by the placement of screws. Here, utilizing CT, we evaluated the normal anatomy of the odontoid process in an Indian population to determine whether one or two screws could be anatomically accommodated to achieve fixation. Methods: CT-based morphometric parameters of the odontoid process were assessed in 200 normal Indian patients (2018–2020). Results: Of 200 patients, 127 were male, and 73 were female. The mean minimum external transverse diameter (METD) was 8.80 mm (range 6.1–11.9 mm). Six (3%) patients had a minimum internal transverse diameter (TD) of >8.0 mm that would allow for the insertion of two 3.5-mm cortical screws without tapping, while 10 (5%) patients had TDs of <7.4 mm; none had diameters of <5.5 mm. The mean length of the implant was 36.45 mm in females and 36.89 mm in males, and the mean angle of screw insertion was 60.34° in females and 60.53° in males. Conclusion: About two-thirds (59%) of the 200 subjects in our study had a METD of <9 mm, indicating the impracticality for introducing second screws for odontoid fixation.

Type II Odontoid Fractures Case Series: History of Seizures a Risk Factor for Failure of Non-operative Treatment of Type II Odontoid Fractures

Introduction:Odontoid fractures are one of the most common injuries to the cervical spine. Type II odontoid fracture treatment varies depending on age, co-morbidities, and fracture morphology. Treatment ranges from cervical orthosis to surgical intervention. Currently fractures with high non-union rates are considered for operative management which includes displacement of >6 mm, increasing age (>40-60 years), fracture gap >1 mm, delay in treatment >4 days, posterior re-displacement >2 mm, increased angulation, and history of smoking. While re-displacement of >2 mm has been associated with increased risk of non-union;, to the best of our knowledge, no studies have looked at the risk factors for re-displacement. Case Report:We present two 26-year-old male patients who were found to have minimally displaced type II odontoid fractures initially treated in a cervical collar. These two patients were subsequently found to have displaced their odontoid fracture after having a documented seizure. Conclusion:We suggest that a history of seizures be considered a risk factor for re-displacement of non-displaced type II odontoid fractures. Keywords:Operative indications odontoid case report, Type II odontoid fracture, Displacement, Seizure, Odontoid fracture displacement, Nondisplaced type ? odontoid fracture.

Posterior fusion for fragility type 2 odontoid fractures

OBJECTIVE The purpose of this study was to evaluate the outcomes of elderly patients with type 2 odontoid fractures treated with an instrumented posterior fusion. METHODS Ninety-three consecutive patients older than 65 years of age in whom a type 2 odontoid fracture had been treated with a variety of C1–2 posterior screw fixation techniques were retrospectively reviewed. RESULTS The average age was 78 years (range 65–95 years). Thirty-seven patients had an additional fracture, 30 of which involved C1. Three patients had cervical spinal cord dysfunction due to their injury. All patients had comorbidities. The average total hospitalization was 9.6 days (range 2–37 days). There were 3 deaths and 19 major complications, the most common of which was pneumonia. No patient suffered a vertebral artery injury. Imaging studies were obtained in 64 patients at least 12 months postsurgery (mean 19 months). Fusion was assessed by dynamic radiographs in all cases and with a CT scan in 80% of the cases. Four of the 64 patients did not achieve fusion (6.25% overall). All patients in whom fusion failed had undergone C1 lateral mass fixation and C2 pars (1/29, 3.4%) or laminar (3/9, 33.3%) fixation. CONCLUSIONS Instrumented posterior cervical fusions may be performed in elderly patients with acceptable morbidity and mortality. The fusion rate is excellent except when bilateral C2 translaminar screws are used for axis fixation.