Orthopedics

Case Report 

Combined Procedure Allowing Atlantoaxial and Atlanto-Occipital Joint Motion for Complex Injuries in the Upper Cervical Spine

Wei Zhao, PhD; Yi Sun, PhD; Gongping Xu, PhD; Jinglong Yan, PhD

Abstract

This study was performed to explore an ideal limited fixation method for the treatment of unstable atlantoaxial fractures that can preserve the range of motion of the occipital and atlantoaxial joints and restore the stability of the upper cervical spine. A 64-year-old man was diagnosed with a complicated injury of the upper cervical spine. The anterior and posterior approach was used to reconstruct the stability of the upper cervical spine while preserving the range of motion of the occipital and atlantoaxial joints. Preoperative imaging and neurologic examinations were performed. Follow-up lasted 24 months. The patient clinically improved after undergoing this novel procedure. Seven days postoperatively, the patient's visual analog scale score was 3. Follow-up contrast computed tomography showed good reduction and fixation in the upper cervical spine. Two weeks postoperatively, the patient displayed good cervical vertebral activity, with no restriction during flexion, extension, rotation, or other movements. No intraoperative or postoperative complications occurred. This modified procedure for restoration of cervical stability may be an improvement over traditional posterior fusion because atlantoaxial motion is preserved. [Orthopedics. 2020;43(4):e329–e333.]

Abstract

This study was performed to explore an ideal limited fixation method for the treatment of unstable atlantoaxial fractures that can preserve the range of motion of the occipital and atlantoaxial joints and restore the stability of the upper cervical spine. A 64-year-old man was diagnosed with a complicated injury of the upper cervical spine. The anterior and posterior approach was used to reconstruct the stability of the upper cervical spine while preserving the range of motion of the occipital and atlantoaxial joints. Preoperative imaging and neurologic examinations were performed. Follow-up lasted 24 months. The patient clinically improved after undergoing this novel procedure. Seven days postoperatively, the patient's visual analog scale score was 3. Follow-up contrast computed tomography showed good reduction and fixation in the upper cervical spine. Two weeks postoperatively, the patient displayed good cervical vertebral activity, with no restriction during flexion, extension, rotation, or other movements. No intraoperative or postoperative complications occurred. This modified procedure for restoration of cervical stability may be an improvement over traditional posterior fusion because atlantoaxial motion is preserved. [Orthopedics. 2020;43(4):e329–e333.]

Although concomitant injuries of the atlas and axis are rarely reported, they account for nearly 3% of cervical spine lesions and 12% of upper cervical spine fractures.1–3 These combination fractures have a significantly higher incidence in patients of advanced age, with falls being the most likely mechanism of injury.4,5 This group of injuries has several unique features distinguishing it from injuries of the subaxial cervical spine: occurrence in an area with a complex bony and vascular anatomy; a relationship of the atlas and axis with the cranial base; and heavy reliance of the intrinsic stability of this region on ligamentous structures. Moreover, a majority of cervical spine injuries occur at the atlantoaxial complex, which may be compromised after a traumatic event, resulting in spinal instability.6 Thus, maintaining the range of motion of the atlantoaxial and atlanto-occipital joints is of clinical concern. Evidence is insufficient to support treatment standards for these cervical spine injuries.7–9

In this article, the authors introduce a new surgical technique for the reduction and stabilization of a unique combination of an axis fracture and a Jefferson fracture. To the best of the authors' knowledge, this is the first report to describe such a technique. The surgical procedure involves C2–3 fusion followed by C1 fixation using a bilateral C1 lateral mass screw that is connected to a rod, a posterior tubercle screw to reduce lateral spread of the lateral masses, and bilateral C2 pedicle screws to recover the ring fracture of the axis by a posterior approach.

Case Report

A 64-year-old man was admitted to the Second Affiliated Hospital of Harbin Medical University. Harbin, Heilongjiang, China, on January 23, 2015, with a history of neck pain after being injured in a fall. Immediately after the fall, he reported cervical pain and was immobilized using a hard collar. At admission, the patient's visual analog scale score was 9. The patient was previously healthy and did not have diabetes, coronary heart disease, or hypertension. Findings were normal on neurological examination. A lateral cervical radiograph showed a type II hangman's fracture with significant translation (Figure 1A–B). Three-dimensional computed tomography (CT) showed type III odontoid fractures, C5–6 spinous fractures, anterior and posterior atlas vertebral arch fractures, and left lateral mass avulsion fractures (Figure 1C–F). No evidence of a spinal cord injury was seen on magnetic resonance imaging. Spinal instability caused by this traumatic lesion led to surgery being performed.

Type II hangman's fracture. A magnetic resonance image (A) and a lateral radiograph (B) of the cervical spine showing a posterior border fracture of the vertebral body. The posterior vertebral arch was separated from the posterior border of the bilateral vertebral arch, and the vertebral body had slid forward significantly. There was no obvious angulation deformity between the C2–3 vertebrae. Three-dimensional computed tomography scans showing type III odontoid fractures (C), C5–6 spinous fractures (D), anterior and posterior atlas vertebral arch fractures (E), and left lateral mass avulsion fractures (F).

Figure 1:

Type II hangman's fracture. A magnetic resonance image (A) and a lateral radiograph (B) of the cervical spine showing a posterior border fracture of the vertebral body. The posterior vertebral arch was separated from the posterior border of the bilateral vertebral arch, and the vertebral body had slid forward significantly. There was no obvious angulation deformity between the C2–3 vertebrae. Three-dimensional computed tomography scans showing type III odontoid fractures (C), C5–6 spinous fractures (D), anterior and posterior atlas vertebral arch fractures (E), and left lateral mass avulsion fractures (F).

Surgical Technique

First, the patient underwent flexion and traction of the skull with an initial weight of 5 kg and terminal traction weight of 6 kg. After significant recovery of the C2–3 dislocation, canal decompression was conducted with internal fixation and bone grafting by an anterior approach to achieve the normal sequence of cervical vertebrae and reconstruct the stability of the cervical vertebrae (Figure 2A). The bilateral fracture of the axial pedicle and both the anterior and posterior arch fractures caused the overall stability of the atlantoaxial vertebra to be significantly affected and the multiple-segment posterior fracture to be fixed. The posterior approach revealed the atlantoaxial vertebrae and the atlantoaxial lateral mass. Posterior tuberculous screw fixation was then performed. The cortical bone on the surface of the posterior tubercle was removed using bone clippers. The screw was prepared by inserting the awl along the posterior lower margin and the anterior upper margin of the posterior tubercle. The screw trajectory was 40° from the frontal plane, allowing the screw canal to break through the anterior superior edge of the atlas cortex. The screw trajectory was approximately 12 mm deep. Therefore, a 3.5 × 12-mm side block screw was selected. The purpose of this application is to treat posterior atlas arch and lateral mass fractures, separate the fracture ends, fix the posterior atlas tubercle screws, and connect the lateral mass screws with titanium rods. This is equivalent to re-establishing the stability between the posterior atlas arch and the lateral mass and reducing and fixing the fracture ends. The titanium rod used to connect the screws was prebent into the posterior arch of the atlas (Figure 2B). The objective was to repair the atlantovertebral lateral mass fracture and the atlantoaxial posterior arch fracture. Headless screw fixation was performed. Finally, the fracture of the vertebral pedicle and vertebral body was restored (Figure 3). A non-posterior pedicle screw is the C2 pedicle screw removed from the universal screw tail. After preoperative traction and anterior surgical reduction and fixation, the anatomical positions of the pedicle and vertebral body segments were restored. The headless screw was used after the tail was removed from the C2 pedicle screw with the purpose of increasing the stability of the fracture end. Postoperatively, antiseptic treatment was continued for symptoms. The patient wore a neck brace for 2 weeks. At 2 years of follow-up, the cervical vertebrae showed good physiological curvature and range of motion was restored (Figure 4).

Intraoperative C-arm cervical lateral position imaging showing that the cervical spondylolisthesis reduction and the internal fixation position were ideal (A). Intraoperative posterior direct visualization showing that C1 was fixed with a lateral mass screw and posterior atlas nodule, 3 screws were connected with a curved titanium rod, and non-rear pedicle screw fixation was performed in the bilateral pedicles of the axis (B).

Figure 2:

Intraoperative C-arm cervical lateral position imaging showing that the cervical spondylolisthesis reduction and the internal fixation position were ideal (A). Intraoperative posterior direct visualization showing that C1 was fixed with a lateral mass screw and posterior atlas nodule, 3 screws were connected with a curved titanium rod, and non-rear pedicle screw fixation was performed in the bilateral pedicles of the axis (B).

Postoperative cervical axial computed tomography scan showing that the atlantoaxial and axial fractures were closed, and internal fixation screws passed through the fracture line (A). Postoperative cervical sagittal computed tomography scan showing that the C2–3 spondylolisthesis was reduced, the axial vertebral body and pedicle fracture line were closed, and the internal fixation position was ideal (B).

Figure 3:

Postoperative cervical axial computed tomography scan showing that the atlantoaxial and axial fractures were closed, and internal fixation screws passed through the fracture line (A). Postoperative cervical sagittal computed tomography scan showing that the C2–3 spondylolisthesis was reduced, the axial vertebral body and pedicle fracture line were closed, and the internal fixation position was ideal (B).

The 7-day postoperative lateral radiograph showing that the C2–3 spondylolisthesis was reduced, the axial vertebral body and pedicle fracture line were closed, and the internal fixation position was ideal (A). The 2-year postoperative lateral radiograph showing that the C2–3 vertebral body was fused with a bone graft, the cervical curvature was ideal, and the internal fixation position was good (B).

Figure 4:

The 7-day postoperative lateral radiograph showing that the C2–3 spondylolisthesis was reduced, the axial vertebral body and pedicle fracture line were closed, and the internal fixation position was ideal (A). The 2-year postoperative lateral radiograph showing that the C2–3 vertebral body was fused with a bone graft, the cervical curvature was ideal, and the internal fixation position was good (B).

Discussion

Atlantoaxial composite fracture accounts for only 3% of all acute cervical spine injuries, 43% of atlas fractures, and 16% of axial fractures.10 Atlantoaxial burst fracture is mainly caused by axial compression of the skull to the atlas and often results from falls from height or car accidents.7,11 Because of the relatively wide C1 vertebral canal, patients with a Jefferson fracture rarely have neurological damage.7,8 Therefore, it is necessary to consider the existence of atlantoaxial instability in the treatment of atlas fractures.

A Jefferson fracture with a concomitant injury of the transverse atlantal ligament (TAL) is usually defined as an unstable Jefferson fracture. The integrity of the TAL is the most important factor in determining the method of treatment. The presence of any of the following indicates TAL rupture12: the total displacement distance of the lateral lumbar of the atlas is greater than 6.9 mm on CT; the front space has shifted greater than 5 mm on CT; an avulsion fracture of the medial margin of the atlantoaxial vertebra is present on CT; or magnetic resonance imaging directly shows a TAL rupture.

The sagittal and axial CT scans of the current patient showed an avulsion fracture on the left side of C1. This suggested that a TAL fracture was possible and that the atlas fracture was unstable. This patient presented with a 3-part fracture of the axis consisting of an odontoid type III fracture and a hangman's type II fracture.

If no obvious atlantoaxial joint or C2–3 joint instability is present in a patient with a simple atlas or axial fracture, conservative treatment of the neck collar can be performed. In the current case, however, the upper cervical spinal cord was in a dangerous state because of the presence of more than 3 fractures of the atlantoaxial and axial vertebrae with simultaneous instability of C2–3. Therefore, surgical treatment was chosen.

The right anterior and posterior arch of the atlas was fractured and separated. The left anterior and posterior arch of the atlas was fractured, but separation was not obvious. A small avulsed bone mass was visible on the left lateral atlas without deviation of the odontoid process, and no lateral displacement or atlantoaxial dislocation was observed.

Considering all of the findings described above, the incomplete injury of the TAL, and the maintenance of stable function, the authors performed posterior screw fixation of the atlas lateral mass to rebuild the stability of the atlanto-occipital joint and atlantoaxial joint with preservation of the joint activity. At the same time as the fixation, a cortical bone screw was inserted into the posterior tubercle of the atlas, the titanium rod was bent, and the 3 screws were connected between the arch and lateral mass to achieve stability after reconstruction. Posterior tubercular screws are mainly used to repair posterior arch fractures; when combined with lateral mass screws, they can reconstruct the stability of the atlas. Because the fixed connection is located in an independent vertebra, the decreased motion of the upper cervical spine caused by occipital cervical fusion and atlantoaxial fusion can be effectively avoided.

This patient's axial vertebra exhibited a complex fracture of the odontoid base with a type II hangman's fracture. Stable surgical reconstruction is required for treatment of C2–3 cervical spondylolisthesis. In this case, the patient underwent preoperative traction and an anterior pry technique to reset the C2–3 dislocation, and fusion of the C2–3 vertebra from the ilium of the body was obtained. At the same time, the posterior pedicle screw fixation achieved a seamless connection between the pedicle and the vertebral body. In this way, the stability of the upper cervical spine was reconstructed while the atlantoaxial activity was guaranteed.

Treatment of such complicated cervical trauma is rare, and treatment philosophies vary. Some scholars advocate conservative treatment for isolated, non-displaced atlas fractures. When such fractures are combined with nondisplaced axis fractures, they can be treated effectively with a rigid cervical collar alone. Isolated displaced atlas fractures or nondisplaced atlas fractures with concurrent displaced axis fractures require immobilization via a halo vest.11 Most scholars believe that unstable fractures should be treated surgically. Dean et al13 obtained a successful outcome for a young patient with an acute combination atlas–type II odontoid fracture that was treated with anterior odontoid and bilateral C1–2 transarticular screw fixation. Liu et al14 treated similar complex upper cervical fractures by combining the anterior and posterior approach with occipital cervical fusion or atlantoaxial fusion. Chaudhary et al15 performed posterior C1–3 fusion surgery for a type IIa hangman's fracture combined with atlantoaxial rotary subluxation.

Scholars who insist on conservative treatment believe that surgical treatment is bound to fuse the cervical spine and lead to decreased activity of it. Conservative treatment for complex upper cervical fractures must involve the use of a halo vest collar. However, because this treatment is invasive and long, it seriously affects the patient's quality of life and increases the risk of severe complications such as nail infection and neck stiffness.

Currently, no guidelines are available regarding the treatment of such complicated cervical fractures. Surgeons choose treatment on the basis of their personal experience and familiarity with certain surgical procedures. It remains unclear how to relieve the pain resulting from conservative treatment and how to avoid the limitations resulting from surgical treatment of the cervical vertebra.

In the current case, after full assessment of the imaging data of the cervical spine, the authors concluded that the patient had C2–3 instability, partial avulsion of the attachment point of the atlas lateral mass without complete disruption of the TAL, and more than 3 fracture parts in the atlas and axis. On the basis of these 3 conditions, the patient's injury was not suitable for conservative treatment. Atlantoaxial fusion is associated with a risk of overtreatment. Therefore, the anterior approach for treatment of the C2–3 fusion was selected, and posterior reconstruction of the atlantoaxial stability was performed using lateral mass and pedicle screws. Postoperatively, a cervical collar was placed, and the patient rested for 2 weeks. Functional rehabilitation exercise was performed thereafter. At 2 years of follow-up, the patient had good cervical activity, good cervical sequence, ideal position of the internal fixator as shown on radiographs, and no fracture or dislocation.

Conclusion

Three or more simultaneous atlantoaxial fractures are rare, and treatment strategies have not been standardized. First, the atlantoaxial stability needs to be properly assessed. Second, in the absence of complete rupture of the TAL, lateral mass screws and pedicle screws should be used to restore the atlantoaxial fractures. While restoring stability, the atlantoaxial activity should be preserved as much as possible. Patients can achieve a satisfactory prognosis with the adoption of these surgical concepts and methods.

References

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Authors

The authors are from the Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China.

Drs Zhao and Sun contributed equally to this work and should be considered as equal first authors.

The authors have no relevant financial relationships to disclose.

Correspondence should be addressed to: Jinglong Yan, PhD, Second Affiliated Hospital of Harbin Medical University, 246 Xuefu Rd, Harbin, Heilongjiang, China ( yanjinglong1964@163.com).

Received: January 27, 2019
Accepted: September 23, 2019
Posted Online: May 07, 2020

10.3928/01477447-20200428-02

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