Wright's Technique with the Addition of Visualized Axial Cortical Windows in Odontoid Fractures

Abstract

This study sought to investigate and evaluate a modified axial translaminar screw fixation for treating odontoid fractures. We performed a retrospective study at Wenzhou Medical University Affiliated Second Hospital between March 2016 and June 2018. We retrospectively collected and analyzed the medical records of 23 cases with odontoid fractures. All patients were identified as type II odontoid fractures without neurological deficiency and serious diseases following the classification of Anderson. The average age, gender ratio, and body mass index (BMI) were 54.3 ± 11.1 years, 12 men to 11 women, and 22.6 ± 2.4 kg/m² , respectively. Patients in this study accepted screw fixation using our modified axial translaminar screw fixation combined with atlas pedicle or lateral mass screw fixation. Within the technique, a small cortical "window" was dug in the middle of the axial contralateral lamina, such that the screws in the lamina were visualized to prevent incorrectly implanting the posterior spinal canal through the visualized "window." A total of 46 bone screws were accurately inserted into the axial lamina without using fluoroscopy. The length of all translaminar screws ranged between 26 and 30 mm, while the diameter was 3.5 mm. During the follow-up survey, the visual analog scale (VAS) and neck disability index (NDI) were measured. We provide a simple modification of Wright's elegant technique with the addition of "visualized windows" at the middle of the axial lamina. In all patients, screws were inserted accurately without bony breach and the screw angle was 56.1 ± 3.0°. Mean operative time was 102 ± 28 min with an average blood loss of 50 ± 25 mL. Postoperative hemoglobin and mean length of hospital stay were 12.0 ± 1.4 g/dL and 10.4 ± 3.4 days, respectively. The average follow-up time of all cases was 14.7 months and no internal fixation displacement, loosening, or breakage was found. All patients with odontoid fractures reported being satisfied with the treatment during the recheck period and good clinical outcomes were observed. At 1, 6, and 12 months, NDI and VAS showed that the symptoms of neck pain and limitations of functional disability improved significantly during follow-up. Our results suggest that the modified translaminar screw fixation technique can efficiently treat Anderson type II odontoid fracture, followed by the benefits of less soft tissue dissection, simple operation, no fluoroscopy, and accurate placement of screws.

Keywords: Axial translaminar screws; Axis; Odontoid fractures; Visualized window; Wright's technique.

Fig. 1

Schematic diagram of modified axial translaminar screw fixation. (A) Normal axis. (B) A high‐speed drill used to generate a small “entry” cortical point at the junction of the axial spinous process and lamina. (C) A high‐speed drill used to dig a small cortical “window” in the middle of the axial contralateral lamina. Cancellous bone was removed while the inner lamina was preserved. (D) Axis with an “entry” and a cortical “window.” (E) A thin pedicle finder that can be directly visualized through the unicortical “window.” (F) A screw that can be directly visualized through the unicortical “window.”

Fig. 2

Screw placement of modified Wright's technique. (A) The measurement of screw angle in the preoperative imaging. (B) The screw placement in postoperative imaging.

Fig. 3

Measurements of visual analog scale (VAS) scores (A) and neck disability index (NDI) scores (B) for patients with modified axial translaminar screw fixation during follow‐up. * = P < 0.05 compared with the previous follow‐up time.

Fig. 4

Imaging data of a typical case. Male, 51 years old, with Anderson II A odontoid fracture, treated with atlantal lateral mass screw combined with bilateral modified axial translaminar screws and bone graft fusion. (A, B) Preoperative X‐ray and CT showed odontoid fracture type II A. (C, D) Postoperative roentgenographs showed screws were in good position. (E) Postoperative CT showing that odontoid fracture healed after 3 months postoperatively.

Fig. 5

Male, 50 years old, with Anderson II B odontoid fracture, treated with atlantal lateral mass screw combined with modified bilateral axial translaminar screws. (A) Preoperative CT showed type II B odontoid fracture. (B, C) Postoperative X‐ray demonstrated that screws were in good position. (D) Intraoperative imaging. (E) Postoperative CT showed odontoid fracture healed after 3 months postoperatively.

Fig. 6

A 45‐year‐old woman with Anderson II A odontoid fracture. (A) Preoperative CT showed odontoid fracture II A. (B, C) Postoperative roentgenographs showed screws were in good position. (D) Postoperative CT indicating that the odontoid fracture healed after 3 months postoperatively.