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CASE REPORT
Year : 2022 | Volume
: 70
| Issue : 8 | Page : 318-321
Failure of C2-3 Anterior Arthrodesis for the Treatment of Atypical Hangman's Fractures, a Case Series
Zaid S Aljuboori, Samer S Hoz, Maxwell N Boakye
Department of Neurological Surgery, University of Louisville School of Medicine, Preston St, Louisville, KY, United States
Correspondence Address:
Zaid S Aljuboori
220 Abraham Flexner Way, Ste.1500, Louisville, KY - 40202
United States
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/0028-3886.360915
Study Design: Case report series.
Background: The treatment strategy may differ between typical and atypical Hangman's fracture (AHF). Hangman's fracture is a fracture of bilateral pars interarticularis of the axis. Most can be treated using a collar. Surgery is reserved for unstable fractures. AHF has different features such as pedicle involvement. Here, we present three cases with AHF that failed anterior arthrodesis.
Materials and Methods: We describe here 3 cases of atypical hangman's fracture managed using anterior approach supplemented by posterior fixation depending upon the fracture morphology.
Results:
Case 1: A 48-year-old female with AHF treated with C2-3 ACDF, follow up x-ray at two months showed new C2-3 anterolisthesis. The patient underwent C3 corpectomy with C2-4 arthrodesis and C1-C4 posterior instrumentation.
Case 2: A 54-year-old male with AHF. He underwent C2-3 ACDF, postoperative x-ray showed C2-3 anterolisthesis. He underwent C1-C3 posterior arthrodesis.
Case 3: A 69-year-old male with AHF. He underwent C2-3 ACDF, postoperative x-ray showed C2-3 anterolisthesis. He underwent C1-C3 posterior arthrodesis. Follow up x-rays showed stable instrumentation with bony fusion. Anterior arthrodesis can treat typical Hangman's fractures, but not necessarily atypical fractures.
Conclusion: Atypical hangman's fracture should be managed with caution. Anterior arthrodesis although achieves excellent fusion in typical fractures, may require supplementation by posterior fixation especially in the presence of C2 pedicle involvement.
Keywords: Anterolisthesis, arthrodesis, atypical, fracture, Hangman's, instrumentation, spine, trauma
Key Messages: Anterior arthrodesis although achieves excellent fusion in typical hangman's fractures, may require additional posterior fixation, especially in the presence of C2 pedicle involvement.
Traumatic spondylolisthesis of the axis (Hangman's fracture) is the second most common type of axis fractures.[1],[2] The injury involves fracture of bilateral pars interarticularis.[1],[3] Most fractures are due to falls or motor vehicle accidents (MVAs). The mechanism involves hyperextension and axial loading which lead to transmission of the weight of the skull through the occipital condyles to the C1-2 lateral masses, where it converges at the base of C2 and pass through the weak pars.[3],[4],[18]
Most patients with this injury are neurologically intact with only 6.5% present with neurological injury.[5] Various classification systems exist but the system by Effendi et al. has been the most accepted.[6] Later, Levine and Edwards modified this system, resulting in the most widely used classification system.[7] Atypical Hangman's fractures (AHF) is a subgroup of fractures with features that are different from the original description.[8] The atypical features include fracture of the pedicle, lamina, or posterior vertebral body.[8],[17] AHF has a high incidence, but literature focusing on surgical management of these fractures is sparse. Here, we describe three cases of AHF that failed anterior C2-3 arthrodesis.
Case Presentation
Case 1
A 48-year-old female with isolated C2 fracture (left pars and right pedicle) due to MVA [Figure 1]a. The C2-3 disc, anterior longitudinal, and posterior longitudinal ligament (ALL/PLL) were intact. The patient was neurologically intact. She was treated with C2-3 anterior discectomy and arthrodesis. Postoperative x-ray showed stable instrumentation. During 2 months follow-up x-ray showed C2-3 anterolisthesis (9 mm) with nonunion of the fracture [Figure 1]b. She then underwent a C3 corpectomy with C2-4 anterior arthrodesis followed by a C1-C4 posterior instrumentation [Table 1].
Figure 1: (a) CT C-spine [axial] shows right pedicle fracture. (b) C-spine X-ray [lateral] shows C2-3 arthrodesis with new anterolisthesis. (c) C-spine X-ray [lateral] shows C3 corpectomy with C2-4 and C1-C4 arthrodesis
Table 1: Patient demographics, type of injury, treatment method(s), and outcomesCase 2
A 54-year-old male who was involved in a bike accident, he had C2 fracture that involved both pedicles and the posterior vertebral body [Figure 2]a. Additionally, he had C1 posterior arch fracture. The C2-3 disc was disrupted with tear of the ALL. The patient was neurologically intact, he underwent a C2-3 anterior discectomy and arthrodesis. Postoperative computed tomography scan showed worsening of C2-3 anterolisthesis (6 mm) [Figure 2]b. He then underwent a C1-C3 posterior cervical instrumentation with reduction of the fracture [Table 1].
Figure 2: (a) CT C-spine [axial] shows pedicles fracture. (b) CT C-spine [sagittal] shows new C2-3 anterolisthesis. (c) C-spine X-ray [lateral] shows reduction of C2-3 with C1-C3 posterior arthrodesisCase 3
A 69-year-old male who was involved in an MVA, which resulted in C2 fracture that involved both pedicles [Figure 3]a. The C2-3 disc was disrupted. The patient was neurologically intact, and he was treated with C2-3 anterior discectomy and arthrodesis. Postoperative x-ray showed worsening of C2-3 anterolisthesis with angulation [Figure 3]b. He then underwent a C1-C3 posterior cervical instrumentation with reduction of the fracture [Table 1].
Figure 3: (a) CT C-spine [axial] shows left pedicle fracture. (b) C-spine X-ray [lateral] shows C2-3 arthrodesis with anterolisthesis. (c) C-spine X-ray [lateral] shows reduction of C2-3 with C1-C3 posterior arthrodesis Results All patients remained neurologically intact. There were no operative complications. On follow-up, all patients remained neurologically stable with x-rays showed stable instrumentation with bony fusion [case 1 [Figure 1]c], case 2 [Figure 2]c, and case 3 [Figure 3]c.
DiscussionHangman's are common cervical spine fractures.[9],[19] The fracture type and patient condition dictate the choice of treatment modality. Levine I fractures can be treated with collar immobilization for 8--14 weeks with more than 90% fusion rate.[9] Levine II fractures can be treated with reduction with cervical traction followed by halo vest placement.[9] Levine IIA fractures are unstable and should be reduced with head extension followed by halo vest application or surgical fixation. The halo vest immobilization can result in 95% union rate.[9] Levine III fractures are unstable and require surgical stabilization.[8] Of note, there are some reports that used special type of traction called bidirectional traction to treat type III Hangman's with rotatory subluxation of C1-2 with success.[10]
Surgical fixation is recommended for unstable fractures (>5 mm subluxation or high degree angulation). It also indicated for fractures with C2-3 disc disruption or fractures that failed external immobilization. [9],[11] The available surgical options include anterior (C2-3 discectomy and arthrodesis or C3 corpectomy and C2-4 arthrodesis) or posterior approaches (C1-3 or C2-3 arthrodesis).[20],[23] Both approaches have comparable fusion rates.[12] The anterior approach is more appealing because its less invasive with high fusion and low complication rates.[4],[13],[24],[25] It is indicated for cases with C2-3 disc herniation resulting in canal narrowing or spinal cord compression.[13] Murphy et al.[14] reported that both anterior and posterior approaches provide high fusion rate in Hangman's fractures, but neither seem to be superior. Al-Mahfoudh et al. reported a study of 41 patients with Hangman's fractures, with 68.2% of the fractures were atypical. More than 90% of fractures were stable and were managed with cervical collar or halo orthosis. The bony union was achieved in all patients on radiologic follow-up.[15]
Our patients were initially treated with C2-3 ACDF within 2 weeks of injury and were placed in rigid cervical orthosis before and after surgery. Failure of the anterior arthrodesis was evident in the initial post-operative imaging in two cases and on the 2 months follow-up for the third one. The worsening of the C2-3 anterolisthesis was not associated with screw pull-out or breakage. This indicates that the new anterolisthesis was unlikely to failure of the hardware. The posterior spinal arthrodesis was done to restore the alignment and provide additional stabilization of the C2-3 motion segment. With one exception, in case 1 and due to high grade anterolisthesis and angulation, a C3 corpectomy with C2-4 anterior arthrodesis was done to correct the deformity, and it was followed by C1-C4 posterior arthrodesis.
All cases had involvement of the C2 pedicle, and only one case had involvement of the posterior vertebral body and disc disruption was evident in 2 cases. Collectively, we can infer that AHF can be associated with failure of anterior C2-3 arthrodesis. Of note, our findings are mere association, further studies including biomechanical testing maybe necessary to establish causality. The literature is scarce on the best treatment option for AHF. Anterior arthrodesis may not be the ideal option for AHF due to the asymmetric nature of the fracture. It may lead to unsatisfactory reduction, and increase the chance of angulation and/or anterior translation. In addition, the anterior approach treat the C2-3 anteroposterior malalignment and instability, but it provides lower stability with lateral bending and axial rotation. In comparison, posterior C2-3 arthrodesis has been shown biomechanical superiority to anterior fusion with higher stability with lateral bending, flexion and axial rotation.[16] To properly address the surgical stabilization of AHF, preoperative imaging analysis is crucial. The analysis should focus on axial, coronal, and sagittal planes to better understand the fracture anatomy.[16] Proper exposure of the fracture fragments, adequate reduction of the fracture in all planes (axial, coronal, and sagittal), and placement of screws across the fracture line are crucial for successful fusion.[16] At our institution, we evaluate all Hangman's fracture images for atypical features in all planes (axial, coronal, and sagittal). Initially, we try to achieve multiplanar closed or intraoperative reduction, then followed by a fusion procedure. We use either C2-3, C1-3, or combined anterior and posterior approach if there is additional C2/3 facet dislocation.
ConclusionAnterior arthrodesis offers >90% union rate in typical Hangman's fractures, it may not be the case for the atypical fractures. We suggest that AHF especially with pedicle(s) involvement may require a different treatment approach to achieve reduction, stabilization, and bony fusion.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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