C-2 arteriovenous fistula presenting as a pathologic hangman's fracture: case report

The authors report on an 81-year-old woman with a pathologic hangman's fracture secondary to a complex arteriovenous fistula (AVF). The patient presented with severe, unremitting neck pain and was found to have fractures bilaterally through the pars interarticularis of C-2 with significant anterior subluxation of C-2 over C-3 along with widening of the left transverse foramen. Due to an abnormally appearing left vertebral artery (VA) on CT angiography, the patient underwent conventional angiography, which revealed a complex AVF stemming from the left VA at the level of C-2 with dilated posterior cervical veins and a large venous varix. Given the radiographic evidence of bone remodeling and the chronicity of the AVF, it is believed that the C-2 vertebra was weakened over time by the pulsatile and compressive force of the vascular malformation eventually leading to fracture with minimal stress. Coil embolization of the AVF was performed followed by surgical fixation of C-1 to C-4. This case highlights the importance of investigating an underlying disease process in patients who present with significant spinal fractures in the absence of trauma.

Management of Typical and Atypical Hangman's Fractures

Study Design Retrospective study of a prospectively maintained database. Objective Our aim was to retrospectively review management and outcomes of patients with low-grade hangman's fractures, specifically looking at differences in outcomes between collars and halo immobilization. We also studied fracture patterns and their treatment outcomes. Methods Forty-one patients with hangman's fractures were identified from 105 patients with axis fractures between 2007 and 2013. Typical hangman's fractures were defined as traumatic spondylolisthesis of the axis causing a bilateral pars interarticularis fracture. Fractures involving the posterior cortex of C2 on one or both sides or an asymmetrical pattern were defined as atypical. Results There were 41 patients with a mean age of 59 years, with 13 (31.7%) typical and 28 (68.2%) atypical fractures. There were 22 (53.6%) type 1 fractures, 7 (41.4%) type 2 fractures, and 2 (4.9%) type 2a fractures in this series. Cervical collars were used to manage 11 patients (27% of all patients with hangman's fractures) and halo orthosis was used in 27 (65.8%). Three (7.3%) patients underwent surgical fixation of the fracture. Bony union was achieved in all patients on radiologic follow-up. Permanent neurologic deficit occurred in one patient due to associated injuries. Neck pain and stiffness were reported more commonly in the atypical group, but this finding was not statistically significant. Conclusions The majority of hangman type fractures can be treated nonoperatively. We found no difference in outcomes between a rigid collar or halo immobilization for treatment of low-grade fractures. Radiologic follow-up is essential to identify cases of nonunion.

Traumatic Spondylolisthesis of the Axis Vertebra in Adults

Study Design Narrative review. Objective To elucidate the current concepts in diagnosis and treatment of traumatic spondylolisthesis of the axis. Methods Literature review using PubMed, Google Scholar, and Cochrane databases. Results The traumatic spondylolisthesis of the axis accounts to 5% of all cervical spine injuries and is defined by a bilateral separation of the C2 vertebral body from the neural arch. The precise location of the fracture line may vary widely. For understanding the pathobiomechanics, the involvement of the C2-C3 disk is essential. Although its synonym "hangman's fracture" suggests an extension moment as primary injury mechanism, flexion moments are also proven to cause such fracture morphology. The axial force vector (distraction versus compression) is thought to have a significant effect on the neurologic involvement. The most widely accepted classifications, according to Effendi and modified by Levine, regard the displacement of the C2 vertebral body and possible locking of the facet joints. For decisions on conservative versus surgical therapy, a definitive statement about the stability is essential. The stability is determined by involvement of the C2-C3 disk and longitudinal ligaments, which frequently cannot be assessed by X-ray or computed tomography alone. The assessment of this soft tissue injury therefore requires additional imaging either by magnetic resonance imaging to display the disk and longitudinal ligaments or dynamic fluoroscopy to assess functional behavior of the C2-C3 motion segment. If stability is proven, an immobilization of the cervical spine in a semirigid cervical collar is sufficient. Unstable lesions require surgical stabilization. The standard procedure is an anterior C2-C3 diskectomy and fusion, because of the lower morbidity of the anterior approach and the motion preservation between C1 and C2. In rare cases (irreducible locked facet joints, the necessity of decompression of the vertebral artery, contraindication for anterior approach), a posterior approach is sometimes necessary. Isolated direct screw osteosynthesis is of little value, because it only makes sense in cases with an intact C2-C3 disk, which is usually regarded as stable and therefore might be treated conservatively. Conclusions Overall, the clinical evidence regarding traumatic spondylolisthesis of the axis is very low and mainly based on small case series, expert opinion, laboratory findings, and theoretical considerations.

Determining optimal c2 pedicle screw placement and length in patients with axis traumatic spondylolisthesis: a case series

We sought to determine the optimal placement and screw length for C2 pedicle screw fixation to compare with recommendations in literature. Nine patients were included in this study and underwent C2 pedicle instrumentation either for a hangman's fracture as part of C2 pedicle-C3 lateral mass fixation or for C2-C3 subluxation. All nine patients had good postoperative improvement with satisfactory fracture consolidation. Mediolateral and rostrocaudal angulations of the inserted screws were not consistent with the traditional angulations of 20 degrees in each plane due to the fracture lines and the anatomical variations. Because the frequent observation of the bony anatomical variations and the lines of fractures brought about by trauma, a shift from the classic 20 degrees of angulation in both trajectories has been concluded. But still fixed angles of angulations cannot be generalized. As a consequence, accurate preoperative planning can be obtained by computed tomography with three-dimensional images so that it gives the surgeon a good prediction of the best length of utilized screws in the procedure and the best angulations for safety of the neighboring neurovascular structures.

Injuries of the upper cervical spine: A series of 28 cases

BACKGROUND

There are very few published reports of upper cervical spine injuries from our country and there is a heavy bias towards operative treatment of these injuries. We present below our experience of upper cervical injuries over the last four years.

MATERIALS AND METHODS

Twenty eight patients (20 males, 8 females) with upper cervical spine injury (including Occiput, Atlas and Axis) were treated and were followed-up for an average of 11.2 months. The data was analyzed retrospectively with regards to the location and type of injury, the treatment offered (conservative or operative) as well as the final clinical and radiological outcome.

RESULTS

The clinico-radiological outcome of treatment of these injuries is mostly very good with few complications. Other than a single case of mortality due to associated head injury there were no major complications.

CONCLUSION

Management of these patients needs a proper evaluation to arrive at the type of injury and prompt conservative or operative treatment. Treatment is usually safe and effective with good clinical and radiological outcome.