Expansive laminoplasty

Introduction Ossification of the posterior longitudinal ligament (OPLL), considered to be one of the clinical manifestations of a generalized disease, diffuse idiopathic skeletal hyperostosis (DISH), appears as an abnormal radiopacity along the posterior margins of the vertebral bodies on lateral-view radiographs [1]. Most patients with OPLL have only mild, subjective complaints such as neck pain and numbness in their hands. However, some patients develop myelopathy, including gait disturbance and clumsiness of the fi ngers; and they undergo surgery when their symptoms are aggravated. Anterior decompression followed by spinal fusion (ADSF) used to be the preferred treatment for OPLL because it was considered logical to remove anterior pathological structures anteriorly. With anterior surgery, ossifi ed ligaments are extirpated or fl oated anteriorly to obtain spinal cord decompression [2,3]. However, anterior surgeries were not without complications, including traumatic spinal cord injury caused by unstable movement of the ossifi ed mass during extirpation, especially when a lesion involves multiple levels [4]. It has been reported that the rate of complications including cerebrospinal fl uid leakage and pseudarthrosis with or without dislodgement the grafted bone was 24%, and the rate at which a salvage operation was required was 12.5% [5]. Our analyses on the longterm results of ADSF also revealed that recurrent myelopathy due to the development of adjacentsegment diseases was not uncommon, especially in those with developmental spinal canal stenosis [6].