Tear-drop Fracture of the Axis: Non-operative Treatment of Two Cases : Case Report

Tear-drop fracture of the axis are rare. It is characterized by a fracture of the anterior-inferior corner of the C2 body. The mechanism is usually in extension which is different from the tear-drop of lower cervical spine. We report two cases of adults who sustained a road trac accident. They did not have any neurological decit. The diagnosis was made on radiological examination. They both were treated conservatively with rigid immobilization and recovered well. Tear-drop fracture of the axis are usually stable. Imagery is the key of the diagnosis. Neurological decit is rare. Conservative management usually give good outcome for non-complicated cases. We present two cases of patient with tear-drop fracture We study means our cases the management strategy of type


Abstract
Tear-drop fracture of the axis are rare. It is characterized by a fracture of the anterior-inferior corner of the C2 body. The mechanism is usually in extension which is different from the tear-drop of lower cervical spine. We report two cases of adults who sustained a road tra c accident. They did not have any neurological de cit. The diagnosis was made on radiological examination. They both were treated conservatively with rigid immobilization and recovered well. Tear-drop fracture of the axis are usually stable. Imagery is the key of the diagnosis. Neurological de cit is rare. Conservative management usually give good outcome for non-complicated cases.

Introduction:
Tear-drop fractures of cervical spine are rare. Those involving the axis are extremely rare. They manifest by a fracture of the anterior inferior corner of the C2 body. This type of fracture occurs in elderly following minor trauma or in middle-aged population owing high energy trauma. The mechanism, the stability, the complications and the treatment are different from tear-drop fracture of the lower cervical spine. We present two cases of patient with tear-drop fracture of the axis. We aim to study by means of our cases the management strategy of this type of fracture.
Case Report:

Case 1
A 64-year-old male, with no medical history, was a car-driver who was in a road tra c accident. He presented to the emergency department with severe neck pain. There was no associated head trauma. At the time of the examination the patient was fully conscious with a Glasgow Coma Scale at 15 with no respiratory or hemodynamic distress and had a neck pain with inability to move the neck. Motor and sensory examination were normal. Planters were exor. Hoffman sign was negative. The patient was immobilized in a rigid cervical collar. Lateral radiograph of cervical spine showed a tear drop fracture of C2 vertebrae (Figure 1a). A Computed Tomography (CT) scan was conducted and showed an avulsion of the anterior inferior portion of C2 ( Figure 1b). The CT did not show any posterior displacement of the C2 vertebrae. The retained diagnosis was axis tear-drop without neurological de cit. The decision was to manage the patient conservatively with a rigid cervical immobilization for 6 weeks. After 6 weeks, we noted a full recovery without any complications.

Case 2
A 49-year-old man, with no medical history, sustained a tra c road accident. The patient presented to the emergency room with sever neck pain. At the time of the examination, the patient was fully conscious with a Glasgow Coma Scale at 15 without any other distress. The patient could not move his neck. Motor and sensory examination were normal. The patient was immobilized in a rigid collar and had a full body CT. The CT showed a fracture of the anterior inferior wedge of C2 ( Figure 2). The retained diagnosis was a tear-drop fracture of C2 without neurological de cit. We decided to manage the patient conservatively with a rigid immobilization for 6 weeks. After 6 weeks, the patient fully recovered with no complications.

Discussion:
Tear-drop fracture of the axis is an avulsion of the anterior inferior angle of the C2 vertebrae. This injury occurred in 3,2% of all fractures of the axis in the Roy-Camille series (1). The strength of our case report is that it is about 2 patients both treated conservatively. The limitation is the short follow-up. This fracture differs from lower cervical spine fracture by its mechanism which is an extension for C2 while its exion for the lower cervical spine (2). Road tra c are the most common circumstance in the study of Hu et al.
(2). Neurological de cit is rare (3). Half of the tear-drop injury are associated with other level injuries which may be the cause of neurological de cit (1,4). This type of fractures is usually stable since posterior elements are intact (5).
Diagnosis can be made with lateral radiography of the cervical spine (6). CT-scan is the ideal investigation. Lingering over indirect signs of instability should be made: widening of the interspinous distance at the site of injury, narrowing of the disc space resulting of the damage to the intervertebral disc, loss of parallelism due to subluxation of the facet joints as a result of disruption of their capsules, posterior displacement of the vertebral body (greater than 3 mm at the CT-scan (7)) which indicates disruption of the posterior longitudinal ligament and the presence of vertebral soft-tissue widening which is evidence of anterior longitudinal damage (5). MRI can be helpful for the diagnosing an unstable injury especially with high velocity trauma, neurological de cit and soft tissue swelling (5). In our cases, we did not explore patients with MRI since there was no neurological de cit or any sign of instability in the CTscan. The treatment of tear-drop axis fracture is controversial. All authors agree that a neurological de cit is an indication of surgical treatment with decompression and fusion (2, 3, 6-9). Agrawal et al.  (7). The authors argument was that there was medullary canal narrowing at the level of C2 without any anomaly of the C2-C3 intervertebral disc. The outcome of this fracture treated conservatively or surgically is usually good (2). In our cases, the conservative treatment lead to a good outcome for stable fractures with no neurological de cit. Both our patients were satis ed with the treatment they received and their outcome.

Declarations
No funding was received for this manuscript.

Con ict of interest:
The authors declare no con ict of interest. Informed consent was obtained from both patients described in this report.

Availability of data and material:
Data sharing not applicable to this article as no datasets were generated or analyzed during the current study.