Double-level myelopathy due to atlantoaxial dislocation (os odontoideum) and subaxial cervical spondylosis with angular kyphosis
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How to cite this article: Rahimizadeh A, Soufiani H, Rahimizadeh S. Double-level myelopathy due to atlantoaxial dislocation (os odontoideum) and subaxial cervical spondylosis with angular kyphosis. Surg Neurol Int 2020;11:100.
Abstract
Background:
The surgical management of cervical spondylotic myelopathy (CSM) attributed to os odontoideum (OO with atlantoaxial instability atlantoaxial instability) and subaxial kyphosis together pose significant surgical challenges.
Case Description:
An elderly male presented with CSM/myelopathy and severe quadriparesis attributed to an unstable OO and 87° fixed, subaxial cervical kyphosis. After performing a 540° spinal cord decompression with atlantoaxial fixation, the patient did well.
Conclusion:
Double-level CSM due to an unstable OO and subaxial kyphosis is rare and typically requires combined 540° decompression and stabilization.
Keywords
INTRODUCTION
Unstable os odontoideum (OO) with atlantoaxial dislocation and subaxial “draping of the cervical spinal cord” over a kyphotic deformity contributed to dual-level significant cord compression and myelopathy in a 78-year-old male.[1-11]
Following a 540° anterior-posterior-anterior decompression and fusion, the patient improved.
CASE REPORT
A 78-year-old wheel chair bound male developed a severe spastic quadriparesis with sphincter disturbance over a 2-year period. His modified Japanese Orthopedic Association (mJOA) score was 8. Cervical X-rays, MR, and CT studies demonstrated OO instability with subaxial C4-C6 cord compression; there was an accompanying 87° fixed kyphosis [Figures 1-3].
Surgical intervention
The patient underwent a C2 to C7 laminectomy with C1 lateral mass screw placements and insertion of bilateral pedicle screws from C2 to C7 bilaterally [Figure 4]. After assembling a rod on one side from C2 to C7, multilevel Smith-Peterson osteotomies (SPOs) were performed on the contralateral side and vice versa [Figures 5 and 6]. An expandable cage was placed within the corpectomy site; when it became loose intraoperatively, the patient had to undergo anterior cage repositioning. Notably, all procedures were performed utilizing intraoperative neuromonitoring that demonstrated no changes.
The intraoperative cervical cross-table X-ray ultimately confirmed adequate C1 to C7 instrumentation with a 100° correction of the kyphosis [Figure 7a]. Three months later, the patient was able to eat and button his shirt without difficulty and ambulated with a walker (mJOA score: 11) [Figure 7b]. At 1 postoperative year, he demonstrated no further recovery, and the cervical X-ray showed no further changes in sagittal alignment [Figure 8].
DISCUSSION
Management of OO with instability
The discovery of a symptomatic OO in an elderly patient is rare; we found only 12 such cases in the literature.[8,9] The management of symptomatic OO with reducible atlantoaxial instability has evolved to now using either a C1-2 screw rod fixation or the Harms technique.[4-8]
Treatment of subaxial CK
With an angular kyphosis from 30° to 90°, 540° surgery with a combination of anterior-posterior-anterior decompression/fusion may be warranted. In this case, while supine, the patient underwent a two-level corpectomy with three-level anterior osteotomy (C4-C6) (ATO).[2] Secondarily, while prone a C2 to C7 laminectomy with C1 lateral mass screw placements, and insertion of bilateral pedicle screws from C2 to C7 with multilevel SPOs were performed (C2-C7) [Figures 8 and 9].[10,11] In addition, a third anterior procedure was required to revise the “loose: anterior construct.”
CONCLUSION
For patients displaying OO/instability and subaxial cervical kyphosis, combined anterior followed by posterior decompression/fusion surgery may be warranted.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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