Elsevier

The Spine Journal

Volume 14, Issue 12, 1 December 2014, Pages 2892-2896
The Spine Journal

Clinical Study
Self-designed posterior atlas polyaxial lateral mass screw-plate fixation for unstable atlas fracture

https://doi.org/10.1016/j.spinee.2014.04.020Get rights and content

Abstract

Background context

Most atlas fractures can be effectively treated nonoperatively with external immobilization unless there is an injury to the transverse atlantal ligament. Surgical stabilization is most commonly achieved using a posterior approach with fixation of C1–C2 or C0–C2, but these treatments usually result in loss of the normal motion of the C1–C2 and C0–C1 joints.

Purpose

To clinically validate feasibility, safety, and value of open reduction and fixation using an atlas polyaxial lateral mass screw-plate construct in unstable atlas fractures.

Study design

Retrospective review of patients who sustained unstable atlas fractures treated with polyaxial lateral mass screw-plate construct.

Patient sample

Twenty-two patients with unstable atlas fractures who underwent posterior atlas polyaxial lateral mass screw-plate fixation were analyzed.

Outcome measures

Visual analog scale, neurologic status, and radiographs for fusion.

Methods

From January 2011 to September 2012, 22 patients with unstable atlas fractures were treated with this technique. Patients' charts and radiographs were reviewed. Bone fusion, internal fixation placement, and integrity of spinal cord and vertebral arteries were assessed via intraoperative and follow-up imaging. Neurologic function, range of motion, and pain levels were assessed clinically on follow-up.

Results

All patients were followed up from 12 to 32 months, with an average of 22.5±18.0 months. A total of 22 plates were placed, and all 44 screws were inserted into the atlas lateral masses. The mean duration of the procedure was 86 minutes, and the average estimated blood loss was 120 mL. Computed tomography scans 9 months after surgery confirmed that fusion was achieved in all cases. There was no screw or plate loosening or breakage in any patient. All patients had well-preserved range of motion. No vascular or neurologic complication was noted, and all patients had a good clinical outcome.

Conclusions

An open reduction and posterior internal fixation with atlas polyaxial lateral mass screw-plate is a safe and effective surgical option in the treatment of unstable atlas fractures. This technique can provide immediate reduction and preserve C1–C2 motion.

Introduction

Evidence & Methods

Surgical intervention in the setting of an atlas fracture often involves substantial loss of cervical motion postoperatively. The authors present their results using a polyaxial screw plate, intended to preserve cervical range of motion.

The authors report on a series of 22 patients treated for atlas fractures using the polyaxial screw plate technique. Average follow-up for patients approximated 2 years postoperatively. Satisfactory results are reported along with “well-preserved” cervical range of motion.

This is a small, retrospective series conducted by the inventors of the polyaxial screw plate. As a result, it is subject to confounding by selection, measurement and possibly information bias. The results of this level IV study can be viewed as a “proof of concept” only. More scientifically robust, independent, analyses are certainly required before surgeons could accept the advertised efficacy of the polyaxial screw plate technique.

—The Editors

Acute fractures of the atlas represent 1% to 2% of spinal column fractures and account for 2% to 13% of all acute cervical spine fractures [1], [2], [3]. First reported by Cooper in 1822 [2], the subsequent historical publication of Jefferson et al. [4] in 1920, and later reports by Segal et al. [5] and Sherk and Nicholson [3] have resulted in the use of the term “Jefferson fracture” to indicate a burst fracture injury of the atlas ring. Atlas fractures have historically been categorized as stable or unstable injuries, based primarily on the structural integrity of the transverse atlantal ligament (TAL). The unstable atlas fracture is an atlas burst fracture with concomitant injury of TAL [6], [7]. Whether an unstable atlas fracture should be treated surgically or nonsurgically is controversial. Nonsurgical treatment of displaced atlas burst fractures confers high rates of nonunion, and neurologic sequelae can arise because of cranial settling at C0–C2. Hence, C1–C2 or occiput-to-C2 fusion has been increasingly popular for treatment of unstable atlas fractures, but normal motion, such as C1–C2 rotation and C0–C1 flexion/extension, is sacrificed [8], [9], [10].

We present in this report a retrospective analysis of 22 cases of open reduction and fixation using an atlas polyaxial lateral mass screw-plate construct in unstable atlas fractures. To our knowledge, this present study is the first to report about the atlas polyaxial lateral mass screw-plate construct and represents the largest case series for the unstable atlas fractures.

Section snippets

Materials and methods

Throughout January 2011 to September 2012, 30 patients with atlas fracture were admitted, accounting for 6.1% of all cervical fractures of the same period. Routine preoperative anteroposterior and lateral radiographs and computed tomography (CT) were collected in each case. Then, all patients underwent magnetic resonance imaging (MRI) before surgery to study the ligament elements of the craniovertebral junction, thus assessing the stability. Particular attention was paid to check for the

Surgical results

The operation was completed successfully in 22 cases. A total of 22 plates were placed, and all 44 screws were inserted into the atlas lateral masses. The mean duration of the procedure was 86 (range 68–122) minutes. The average estimated blood loss was 120 (range 90–400) mL. No patients required blood transfusion. The mean length of the atlas lateral mass screws was 28 (26–30) mm.

Radiological results

On the postoperative CT scan, correct positioning of the atlas lateral mass screws was observed in all 44

Discussion

The atlas is the first cervical vertebra, and as the mythological figure, it supports the globe represented by the head. It is ring shaped and lacks a vertebral body and a spinous process like the other vertebrae. It is formed by anterior and posterior arches attached to two lateral masses. The former portion has a median anterior tubercle, for the attachment of the longus colli muscles. Posterior to the anterior tubercle, there is the fovea dentis, which is the articulation point for the

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    FDA device/drug status: Not applicable.

    Author disclosures: BH: Nothing to disclose. LY: Nothing to disclose. QZ: Nothing to disclose. ZC: Nothing to disclose. DH: Nothing to disclose.

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