Application of the O-arm Intraoperative Imaging System to Assist Anterior Cervical Screw Fixation for Odontoid Fractures

Summary

This study describes the application of the O-arm intraoperative imaging system in odontoid fractures.

Abstract

Odontoid fractures account for a large proportion of cervical spine fractures in the elderly, causing pain in the occiput and the back of the neck and restricting neck movement. Anterior cervical screw fixation is a common surgical procedure to treat odontoid fractures. Due to the special location and complex anatomy of the odontoid, surgeons need to perform intraoperative fluoroscopies repeatedly to ensure correct screw position and avoid damage to the peripheral nerves and vessels of the odontoid. The traditional anterior cervical screw fixation is usually conducted with the assistance of a C-arm. However, compared to the C-arm, an O-arm intraoperative imaging system can provide 3D images during surgery, which improves the accuracy of screw placement. This study retrospectively analyzed patients with anterior cervical odontoid fractures treated in our hospital. The application of the O-arm intraoperative imaging system for assisting screw placement in the treatment of odontoid fractures can reduce intraoperative blood loss, operation time, and trauma to the patients.

Introduction

Odontoid fracture is a common form of cervical spine fracture, accounting for approximately 20% of all cervical spine fractures. Odontoid fracture mainly occurs in adults over the age of 65¹. Odontoid process displacement resulting from an external force acting on the cervical spine is the main cause of odontoid process fractures. The main symptoms of odontoid fracture are pain in the occiput and the back of the neck and immobility. According to Anderson's classification², odontoid fractures can be divided into three types. Type I and type III odontoid fractures can achieve satisfactory results with conservative treatments, while patients with type II odontoid fractures often need surgical treatments^3,4.

Current surgical treatments are anterior and posterior screw fixations. The posterior screw fixation technique provides more stable fixation, while the anterior screw fixation technique maintains 80%-100% of the rotational function of the atlantoaxial vertebra. However, because posterior cervical screw fixation causes greater trauma to patients^5,6, treatment of odontoid fractures using anterior screw fixation is increasingly accepted by spine surgeons. The traditional anterior cervical screw fixation is usually conducted with the assistance of a C-arm. However, the complex structures of the anterior neck, the free fracture end, and the size of the patients all obstruct the accurate placement of screws through the anterior neck. High-quality images are desired when navigating accurate screw placement, which is difficult to achieve using the current C-arm system. Therefore, unexpected intraoperative blood loss and longer operation time, as well as more trauma to the patients, may occur when using C-arm to assist the surgery.

The O-arm intraoperative imaging system can provide CT scan images during the operation. Compared with the traditional 2D intraoperative fluoroscopy, the O-arm intraoperative imaging system can detect screw dislocation during the operation, enabling the surgeon to make timely revisions and avoid secondary surgery⁷. The advanced O-arm intraoperative imaging and navigation system can achieve intraoperative 3D CT imaging and provide precise intraoperative navigation. Studies have confirmed that the application of the O-arm navigation-assisted technique in complex surgery can improve the accuracy of screw placement and reduce internal fixation-related complications^6,8,9. Figure 1 shows the application of the O-arm intraoperative imaging system. This study aims to investigate the application of the O-arm intraoperative imaging system in the treatment of odontoid fractures with anterior cervical screws.

Protocol

This study has been approved by the Ethics Committee of the Third Hospital of Hebei Medical University. The patients signed informed consent, and the patients consented to film and allowed the investigators to use their surgical data. A total of 40 patients were included in this study. 1. Preoperative preparation Select patients based on the following inclusion criteria: i) patients who need surgical treatment due to trauma to the odontoid process of the axis, ii) …

Representative Results

Anterior cervical screw fixations were performed in 40 patients with odontoid fractures, of whom 21 patients underwent surgeries with the assistance of the O-arm intraoperative imaging system (Group O), and 19 patients underwent surgeries with the assistance of the C-arm (Group C). Data are presented as mean (± SD). The average age of Group O was 42.86 (± 10.36) years, while the average age of Group C was 41.05 (± 9.83) years. There was no significant difference in age between the two groups of patients. B…

Discussion

Odontoid fractures are usually caused by violent injury; common symptoms are pain and limited mobility. Some patients also experience nerve compression symptoms. In some patients, the degree of fracture displacement is relatively large, and the fracture fragments compress the spinal cord and cause symptoms of paraplegia and neuralgia. Some patients with odontoid fractures also have symptoms of hand weakness and difficulty in walking. Type II odontoid fractures have poor self-healing potential and often require surgical t…

Materials

Bipolar electrocoagulation tweezers	Juan'en Medical Devices Co.Ltd	BZN-Q-B-S	1.2 mm x 190 mm
Cannulated Lag Screws	Medtronic Sofamor Danek USA ,Inc	873-146	4.0 mm x 46 mm
High frequency active electrodes	ZhongBangTianCheng	GD-BZ	GD-BZ-J1
Laminectomy rongeur	Qingniu	2054.03	220 x 3.0 x 130°
Laminectomy rongeur	Qingniu	2058.03	220 x 5.0 x 130°
Pituitary rongeur	Qingniu	2028.01	220 x 3.0 mm
Pituitary rongeur	Qingniu	2028.02	220 x 3.0 mm
Surgical drainage catheter set	BAINUS MEDICAL	SY-Fr16-C	100-400 mL
Surgical film	3L	SP4530	45 x 30 cm