Traumatic atlantoaxial rotatory subluxation in adults - A case report and literature review.

BACKGROUND: Traumatic atlantoaxial rotatory subluxation (AARS) is extremely rare in adult versus pediatric populations. Patients usually present with post-traumatic neck pain and torticollis. Surgical management aims at reducing the deformity and stabilizing the spine utilizing external orthotics, and/or internal reduction/fixation.
METHODS: A 65-year-old female fell downstairs at home. She complained of neck pain with right-sided tenderness and torticollis. The radiographic studies and CT scan demonstrated AARS. This led to an emergent open reduction with internal fixation at the C1-C2 level.
RESULTS: We identified 25 similar cases of AARS in the English literature. Patients averaged 28.7 years of age and mostly sustained motor vehicle accidents largely treated with traction/orthotics; only six patients required surgical open reduction/internal fixation.
CONCLUSION: In this case, the patient's C1-C2 deformity required open reduction/internal fixation rather than bracing alone. Copyright:

INTRODUCTION

Atlantoaxial dislocations are a heterogeneous group of C1-C2 rotatory subluxations involving the inferior atlanto and superior axial facet articulations.[3,5]

Definitive management of such traumatic unilateral atlantoaxial rotatory subluxation (AARS) varies due to the unique biomechanics of these injuries; they often require an individualized approach.[6] Type I lesions notably occur without attendant ligamentous rupture, allowing the dens to “pivot.” Here, we describe a rare case of traumatic Type 1 C1-C2 AARS that occurred in a 65-year-old female due to a fall that required open reduction/internal fixation.

CASE REPORT

A 65-year-old female sustained a fall from ten steps at her home. She presented with stiffness/ neck pain and reduced range of movement. On examination, she had cervical (C5-C7) and thoracic (T7-L2) spine tenderness and torticollis toward the right. The neurological examination was normal. When plain films demonstrated a T11 fracture, she was placed in a TLSO. In addition, the CT showed a unilateral atlantoaxial rotatory subluxation with a locked right C1 facet and a right-sided intracanalicular bony fragment adjacent to the odontoid process [Figure 1a-d]. The cervical MR confirmed AARS with mal-alignment, right rotatory subluxation of C1 (e.g., less than a third of the articular surfaces were in contact), and a thinned ligamentum flavum narrowing of the spinal canal at the C1 level without spinal cord compression. Further, the transverse and alar ligaments remained intact (Fielding Type I AARS injury) [Figure 2].

Figure 1:

Preoperative CT cervical spine. Sagittal (a), coronal (b), and axial (c and d) bone window CT cervical spine images demonstrate the right atlanoaxial rotatory subluxation (arrows), where the atlas has rotated on the odontoid with no anterior displacement.

Figure 2:

Preoperative axial T2W MRI image shows the rotatory subluxation (arrow).

Surgery

Within 24 h of the fall, and after a failed attempt at external reduction under general anesthesia, the patient underwent an open surgical reduction, and Harms-technique of C1-C2 fusion.[4] The patient’s T11 fracture although initially managed conservatively (e.g., with bed rest and analgesia) 3 weeks later required T10-T12 percutaneous spinal screw/ fixation. The patient uneventfully recovered from both surgeries. The 3-month postoperative cervical films showed satisfactory C1-C2 fusion without instability. Further, at 6 months post-surgery, she was fully neurologically intact [Figures 3 and 4].

Figure 3:

Postoperative CT cervical spine. Sagittal (a), coronal (b), and axial (c) bone window CT cervical spine day 2 after surgery demonstrates the restoration of C1-C2 alignment.

Figure 4:

Flexion (a) and extension (b) cervical spine X-ray at 3 months follow-up shows absence of C1-C2 instability.

DISCUSSION

Atlantoaxial subluxation is rare in the elderly, and early diagnosis and treatment are essential to ensure satisfactory neurological outcomes. Although CT remains the gold standard for documenting these injuries, those with suspected AARS should also undergo MRI for fuller evaluation of the attendant soft tissue injuries (e.g., ligamentous injuries, and/ or extent of spinal cord compression).[1,2]

Literature review of AARS

Using MEDLINE, we identified 25 adults who previously sustained C1-C2 AARS injuries [Tables 1 and 2]. For adults with Type I Fielding injuries, immobilization can result in good outcomes. However, for older patients, this may not sufficiently reduce the subluxation in a timely fashion. Therefore, some older patients may require open reduction/ internal fixation due to osteophytic changes accompanied by locked facets to maximize the quality of outcomes.

Table 1:

Summary of reported cases of atlantoaxial subluxation in adults.

Table 2:

Summary of reported cases characteristics.

CONCLUSION

AARS (especially Fielding I) following cervical trauma is rare in the elderly.

Both CT and MRI studies are essential for documenting the extent of C1-C2 injury, and there should be a low threshold for open operative reduction/fixation.