Progressive Kyphosis Deformity with Facet Subluxation after Cervical Expansive Laminoplasty: A Case Report

INTRODUCTION: In Japan, laminoplasty is often chosen over anterior surgery for the treatment cervical spondylotic myelopathy because most patients are the elderly with multiple stenoses. Laminoplasty is associated with lower perioperative risk, and it can be executed by inexperienced surgeons with relative ease. However, it is also associated with progression of kyphosis, which can result in the deterioration of neck pain and recurrence of myelopathy. Herein, we present a case in which kyphosis deformity progressed post-laminoplasty, resulting in intervertebral joint dislocation and worsening myelopathy. CASE PRESENTATION: A 70-year-old Japanese man who underwent laminoplasty 10 months ago, presented with worsening myelopathy symptoms that had recurred after previously persisting for several days. These symptoms were associated with restenosis of the spinal canal at the C4/5 level due to spondylolisthesis and facet dislocation. As a corrective surgery, we performed anterior-posterior surgery. His post-operative course was almost satisfactory, and post-operative magnetic resonance imaging showed an improvement in spinal cord compression. CONCLUSION: Progressive kyphosis deformity can rarely lead to dislocation of the intervertebral joints, worsening myelopathy. Although the prevention of kyphotic deformity is still difficult, laminoplasty should be performed in patients with a high risk of post-operative kyphosis, such as in this case, considering the possibility of deterioration of myelopathy associated with kyphosis.