One-step reduction and fixation applying transposterior arch lateral mass screw of C1 combined with pedicle screw of C2 and rod system for pediatric acute atlantoaxial rotatory subluxation with injury of transverse ligament

C1 Transposterior Arch Lateral Mass Screws Combined With C2 Pedicle Screw and Rod Fixation for Pediatric Atlantoaxial Subluxation: A Minimal 10-Year Follow-up Outcome Analysis

BACKGROUND AND OBJECTIVES

Although the short-term outcomes of the 1-step reduction and fixation technique using C1 transposterior arch lateral mass screws combined with C2 pedicle screw and rod fixation system for the treatment of pediatric atlantoaxial subluxation (AAS) have been satisfactory, its long-term outcomes and impact on spinal development are not well studied. This study was intended to assess the long-term reliability of this technique for pediatric AAS.

METHODS

A retrospective case series study was conducted to analyze the minimum 10-year follow-up outcomes from 7 pediatric patients with AAS who underwent atlantoaxial fusion using the aforementioned technique. Quality of life and cervical range of motion were both measured thoroughly. In addition, vertical growth within the fusion construct (C1-2), overall cervical alignment, and subaxial cervical spine degeneration were evaluated radiographically.

RESULTS

The mean age of the 7 patients was 8.14 ± 2.41 (6-12) years at the time of surgery. The mean follow-up period was 11.00 ± 1.15 (10-13) years. No patients presented identifiable intervertebral disk degeneration or segmental instability in the subaxial cervical spine except for 1 patient who showed mild intervertebral disk degeneration. Vertical growth did continue within the atlantoaxial complex after surgery (11.90% ± 2.37%); however, there was a decrease in the percentage of vertical growth compared with the corresponding normal populations of the same age and sex. Moreover, there was a significant decrease in the range of cervical extension and rotation motion, and the overall cervical alignment straightened at the latest follow-up.

CONCLUSION

The 1-step reduction and fixation technique is a relatively reliable surgical technique for pediatric AAS, which does not adversely affect the postoperative quality of life or the subaxial cervical degeneration. Nevertheless, certain limitations, such as decreased cervical range of motion and changes in cervical alignment, should be concerned.

Atlantoaxial rotatory dislocation: Surgical treatment in a pediatric patient cohort

•Surgical correction of AARD is an appropriate method of treatment after failed non-operative therapy.•The technique of surgical reduction and C1-C2 fixation using Harms/Goel technique provides excellent clinical outcomes.•In case of traumatic AARD we recommend to consider temporary fixation.

One-Stage Anterior Retropharyngeal Release Followed by Posterior Open Reduction and Intra-Articular Cage Fusion for Treating Chronic Fixed Type III Atlantoaxial Rotatory Fixation

OBJECTIVE

To verify the effectiveness of anterior retropharyngeal release followed by posterior open reduction using long arm reduction screws combined with intra-articular fusion with a cage filled with the local autologous bone for treating fixed Type III atlantoaxial rotatory fixation (AARF).

METHODS

Data from 6 children with fixed AARF were retrospectively reviewed. All patients underwent anterior retropharyngeal release followed by posterior open reduction using long-arm reduction screws combined with intra-articular fusion with a cage filled with local autologous bone. Outcomes were measured using the atlantodental interval value, the Japanese Orthopedic Association score and visual analog scale for neck pain. Patient age, sex, operation time, blood loss, and bone fusion time were recorded. Complications related to the operation were also recorded.

RESULTS

All patients achieved complete reduction and solid bone fusion at follow-up. The atlantodental interval dropped to 2.1 ± 0.5 mm after the operation from a preoperative score of 15.3 ± 3.1 mm (P < 0.05). Japanese Orthopedic Association score significantly improved from a preoperative score of 15.3 ± 0.5 to 17 ± 0 at the final follow-up (P < 0.05). Visual analog scale for neck pain markedly decreased from preoperative 4.5 ± 1.0 to 0.2 ± 0.4 at the final follow-up (P < 0.05). No complication related to the surgical approach or instrumentation was observed.

CONCLUSIONS

One-stage anterior retropharyngeal release followed by posterior open reduction combined with intra-articular cage fusion is effective in treating chronic fixed type III AARF.

Three-Dimensional Printed Model-Assisted Screw Installation in Treating Posterior Atlantoaxial Internal Fixation

The aim of this study was to evaluate the efficacy and feasibility of a life-size 3-dimensional printing assisted posterior internal fixation. We performed a retrospective review of 138 patients who received posterior atlantoaxial internal fixation from October 2009 to March 2015 with a minimum follow-up period of 12 months. Group A included 76 patients who received the conventional free-hand technique. Group B included 62 patients who were treated with internal fixation assisted by 3D printing. The placement accuracy of the screw was evaluated in the computed tomography images according to the methods of Hojo and clinical outcomes were evaluated using the visual analogue scale, the Japanese Orthopedic Association Score, and the Neck Disability Index score. There were no significant differences in the clinical results at any of the follow-up time points regarding the JOA, VAS, or NDI scores between two group. However, compared to Group A, Group B had better results for screw installation (P = 0.003), shorter surgery time (P = 0.001), and less blood loss (P = 0.037). Compared to the conventional free-hand technique, 3D printed model–assisted is helpful to screw placement in atlantoaxial internal fixation, which can be used as a common tool to provides important guidance for upper cervical surgery.

Identifying Factors Predictive of Atlantoaxial Fusion Failure in Pediatric Patients: Lessons Learned From a Retrospective Pediatric Craniocervical Society Study

STUDY DESIGN

Multicenter retrospective cohort study with multivariate analysis.

OBJECTIVE

To determine factors predictive of posterior atlantoaxial fusion failure in pediatric patients.

SUMMARY OF BACKGROUND DATA

Fusion rates for pediatric posterior atlantoaxial arthrodesis have been reported to be high in single-center studies; however, factors predictive of surgical non-union have not been identified by a multicenter study.

METHODS

Clinical and surgical details for all patients who underwent posterior atlantoaxial fusion at seven pediatric spine centers from 1995 to 2014 were retrospectively recorded. The primary outcome was surgical failure, defined as either instrumentation failure or fusion failure seen on either plain x-ray or computed tomography scan. Multiple logistic regression analysis was undertaken to identify clinical and technical factors predictive of surgical failure.

RESULTS

One hundred thirty-one patients met the inclusion criteria and were included in the analysis. Successful fusion was seen in 117 (89%) of the patients. Of the 14 (11%) patients with failed fusion, the cause was instrumentation failure in 3 patients (2%) and graft failure in 11 (8%). Multivariate analysis identified Down syndrome as the single factor predictive of fusion failure (odds ratio 14.6, 95% confidence interval [3.7-64.0]).

CONCLUSION

This retrospective analysis of a multicenter cohort demonstrates that although posterior pediatric atlantoaxial fusion success rates are generally high, Down syndrome is a risk factor that significantly predicts the possibility of surgical failure.

LEVEL OF EVIDENCE

3.

Long-Term Clinical and Radiologic Postoperative Outcomes After C1-C2 Pedicle Screw Techniques for Pediatric Atlantoaxial Rotatory Dislocation

BACKGROUND

Although C1-C2 pedicle screw techniques have been extensively reported in pediatric series, reports on their use have examined only small series with short follow-up periods. The aim of this study was to report pediatric patients with atlantoaxial rotatory dislocation treated with these techniques with a minimum 5-year follow-up.

METHODS

Retrospective review was performed of 27 pediatric patients with atlantoaxial rotatory dislocation who underwent C1-C2 pedicle screw fixation between 2004 and 2012. Clinical and radiographic outcomes were collected and compared with a control group.

RESULTS

Follow-up period was 60-142 months (mean 84 months). Torticollis was completely corrected postoperatively in all but 1 patient. All patients experienced significant pain relief and improvement in range of motion, and 6 patients with neurologic deficits experienced significant improvement postoperatively. Both atlantodental interval and space available for the cord were significantly improved compared with preoperative values. At final follow-up, curvature was lordotic in 20 cases and straight in 7 cases. Compared with the control group, range of motion of the patient group was not significantly different in any direction except in flexion and rotation. Mean anteroposterior diameters of the spinal canal at C1 and C2 levels were not significantly different from the control group.

CONCLUSIONS

C1-C2 pedicle screw techniques are safe and effective for treatment of atlantoaxial rotatory dislocation and result in no obvious limitation on growth in older children.

Accuracy assessment of atlantoaxial pedicle screws assisted by a novel drill guide template

INTRODUCTION

Posterior atlantoaxial pedicle screw fixation is an effective technique for atlantoaxial instability (AAI). However, because of the complex anatomy of the cranio-cervical junction, it remains challenging to insert atlantoaxial pedicle screw precisely and safely. A novel drill guide template was designed for atlantoaxial pedicle screw placement in this study. The purpose of this study is to quantitatively evaluate the accuracy of atlantoaxial pedicle screw placement using the novel drill guide template.

MATERIALS AND METHODS

Between June 2014 and September 2015, 32 consecutive patients with AAI were included. Using the Mimics v17.0 and 3-matic v9.0 softwares, a novel drill guide template with two location holes and guide rods was designed. All patients underwent posterior atlantoaxial pedicle screw fixation assisted by the novel drill guide template. After surgery, the entry point and directions of actual and ideal screw trajectories were measured and compared.

RESULTS

All patients underwent surgery successfully assisted by the novel drill guide template. A total of 128 atlantoaxial pedicle screws were placed for 32 AAI patients. Postoperative CT scans showed two screws in atlas deviated medially from the pedicle cortex and entered the spinal canal about 1 mm but without symptoms. For both atlas and axis, there were no significant differences in entry point or directions between the ideal and actual screw trajectories (P > 0.05). Significant differences were found in preoperative and postoperative Japanese Orthopaedic Association score and Visual Analogue Score (P < 0.001).

CONCLUSIONS

It is feasible to use the novel drill guide template for atlantoaxial pedicle screw placement. The accuracy of screw placement assisted by the novel template is high. More studies are needed to confirm the efficacy of this template.