A Case Report of Complete Dislocation of Atlantoaxial Joint due to a Traumatic and Pathological Axial Lesion

INTRODUCTION

Rheumatic diseases, trauma, and tumor are the common causes of atlantoaxial dislocation.¹ Occipitocervical fusion is generally applicable to upper cervical fracture and dislocation where atlantoaxial fusion is not possible.² It is also one of the effective methods to correct upper cervical instability, and effective bone grafting is also a prerequisite for occipitocervical fusion.³

CASE REPORT

The patient was a 62-year-old male patient who felt neck discomfort 3 days before admission. After being violently attacked by others, he immediately felt neck pain and discomfort with limited movement. Cervical spine computed tomography (CT) scan was performed immediately in the local hospital, indicating that cervical 2 vertebral bone destruction was diagnosed as axial vertebra lesion in the local hospital, and the local hospital suggested to transfer the patient to the hospital for treatment. The family members led the patient to the outpatient clinic of our hospital from a distance of approximately 300 km. In the outpatient examination, the neck was askew to the front and bottom of the right, and the muscle strength of the limbs was normal. American Spinal Cord Injury Association was rated as grade E. X-ray (Figure 1) and CT (Figure 2) examinations of the cervical spine were performed immediately, suggesting pathological axial fracture with atlantoaxial dislocation. The patient was admitted to the Emergency Intensive Care Unit immediately. In the process of transfer, the patient suffered sudden breathing and cardiac arrest, and was immediately given endotracheal intubation and ventilator-assisted treatment. The patient regained spontaneous heart rate and respiration, and sustained cranial traction was given after the condition was stable. Cervical spine CT scan review (Figure 3) indicated good atlantoaxial joint reduction. After the completion of the examination, the patient was given occipitocervical fusion under general anesthesia. Axial vertebral body damage was found during the operation, and local biopsy was taken for examination. Postoperative disease examination suggested that there was a little degenerated bone tissue and necrotic components. Postoperative X-ray showed good internal fixation position (Figure 4).

• Download figure
• Open in new tab
• Download powerpoint

Figure 1

Preoperative anteroposterior x-ray (left) and preoperative lateral x-ray (right). Overlap of the atlas posterior arch with the axial odontoid can be seen on lateral radiographs.

• Download figure
• Open in new tab
• Download powerpoint

Figure 2

Preoperative computed tomography scan sagittal view showed axial odontoid fracture. The fracture end is located in front of the axial body.

• Download figure
• Open in new tab
• Download powerpoint

Figure 3

Complete reduction was seen in the sagittal and coronal positions after cranial traction.

• Download figure
• Open in new tab
• Download powerpoint

Figure 4

Postoperation anteroposterior x-ray (left) and postoperation lateral x-ray (right).

DISCUSSION

Atlantoaxial dislocation can be divided into partial and complete dislocation. Most patients with complete dislocation die on the spot, although it is rare for the patient to travel to many places without death. The reason may be that dislocation accompanied by local bone destruction leads to slight expansion of spinal canal volume, and no respiratory or cardiac arrest occurs in the mobile position. Tuberculosis of the cervical spine is more rarely reported, accounting for 0.3%–1% of systemic tuberculosis.^4,5 Cervical tuberculosis may not be detected at the early stage. Because the patient has no clinical symptoms, the present onset is neck discomfort and posttraumatic atlantoaxial dislocation. Moreover, the role of polymerase chain reaction in the diagnosis of bone tuberculosis is not clear^6,7 because it can be rapidly excluded but cannot be diagnosed,⁸ as shown in this case.

Atlantoaxial tuberculosis often leads to bone destruction of atlantooccipital joint, and local ligament relaxation leads to atlanto-occipital joint instability, so it is particularly important to clear the lesion and reconstruct the stability of upper cervical vertebra.⁹ Although anterior surgery can achieve the purpose of clearing lesions and decompression of spinal canal, anterior surgery is difficult to reconstruct the stability of atlas and occipital region, and posterior surgery can achieve the purpose of bone grafting and fusion internal fixation,¹⁰ but posterior surgery alone is difficult to completely remove lesions, so the selection of surgical methods is particularly important.¹¹ In this case, no local pharyngeal wall abscess was found to form before surgery, so posterior surgery was performed directly after skull traction. However, for other patients with tuberculosis with abscess formation, anterior decompression and posterior fixation and fusion surgery were required, so as to better restore the stability of upper cervical vertebra.

The choice of autologous bone graft or allograft fusion in occipitocervical fusion has always been controversial. Godzik et al¹² believed that the success rate of allograft fusion was relatively high, and the occurrence of complications related to body bone was avoided. The thickest part of the occipital region is mostly located in the external carinal process.¹³ It is still controversial to fix the occipitocervical fusion vertebra to C2 or C3. Pan et al¹⁴ found no statistical difference in the rate of fixed C2 or C3 fusion, but there were more complications in the treatment group than in C2. In this case, due to the obvious axial vertebra destruction, we adopted cervical 3 in the operation, and the postoperative effect was good.

CONCLUSIONS

Continuous cranial traction and posterior occipitocervical fusion are effective methods for treating axial pathological fracture with atlantoaxial dislocation.