Cervical spondylotic myelopathy associated with kyphosis or sagittal sigmoid alignment: outcome after anterior or posterior decompression

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>The effects of sagittal kyphotic deformities or mechanical stress on the development of cervical spondylotic myelopathy, or the reduction and fusion of kyphotic sagittal alignment have not been consistently documented. The aim in this study was to determine the effects of kyphotic sagittal alignment of the cervical spine in terms of neurological morbidity and outcome after 2 types of surgical intervention.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>The authors retrospectively reviewed the records of 476 patients who underwent cervical spine surgeries for spondylotic myelopathy between 1993 and 2006 at their university medical center. Among these were identified 43 patients—30 men and 13 women, with a mean age of 58.8 years—who had cervical kyphosis exceeding 10° on preoperative sagittal lateral radiographs obtained in the neutral position, and their cases were analyzed in this study. Anterior decompression with interbody fusion was conducted in 28 patients, and en bloc open-door C3–7 laminoplasty in 15 patients. Both pre- and postoperative neurological, radiographic, and MR imaging findings were assessed in both surgical groups.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>The mean preoperative kyphotic angle in all 43 patients was 15.9 ± 5.9° in the neutral position. Segmental instability was noted in 26 patients (61%) and reversed dynamic spinal canal stenosis at the level above the local kyphosis in 22 (51%). Preoperative T2-weighted MR images showed high-intensity signal within the cord at and around the level of maximal compression or segmental instability in 28 patients (65%). The mean kyphotic angle in both the neutral and flexion positions was significantly smaller at 4–6 weeks after surgery in the anterior spondylectomy group than in the laminoplasty group (p &lt; 0.001). Furthermore, the angle in the neutral position was significantly smaller on follow-up in the anterior spondylectomy group than in the laminoplasty group (p = 0.034). The transverse area of the spinal cord was significantly larger in the anterior spondylectomy group than in the laminoplasty group on follow-up (p = 0.037). Preoperative neurological scores (assessed using the Japanese Orthopaedic Association scale) and improvement on follow-up ≥ 2 years after treatment (average 3.3 years) were not significantly different between the 2 groups; however, there was a significant difference in Japanese Orthopaedic Association score at 4–6 weeks postoperatively (p = 0.047).</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Kyphotic deformity and mechanical stress in the cervical spine may play an important role in neurological dysfunction. In a select group of patients with kyphotic deformity ≥ 10°, adequate correction of local sagittal alignment may help to maximize the chance of neurological improvement.</jats:p></jats:sec>

Surgical and general complications in 2,961 Japanese patients with cervical spondylotic myelopathy: Comparison of different age groups

“…However, neurological deterioration after laminoplasty for patients with CSM and special conditions, such as ! 10 degrees local kyphosis, has been apparent in longer follow-up studies, so posterior reconstructive surgery with instrumentation or anterior/posterior combined surgeries have recently been recommended 17,18) . The rates of surgical complications for anterior surgery and posterior surgery vary in the literature.…”

Correlation between cervical spine sagittal alignment and clinical outcome after cervical laminoplasty for ossification of the posterior longitudinal ligament

“…In patients with cervical kyphotic deformity, the spinal cord could be compressed by tethering over the apical vertebra or intervertebral disc or by OPLL. 23 In addition to neurological dysfunction, patients may experience severe mechanical neck pain secondary to facet joint disruption.…”

Outcomes of surgical intervention for cervical spondylotic myelopathy accompanying local kyphosis (comparison between laminoplasty alone and posterior reconstruction surgery using the screw-rod system)

“…Uchida et al [1] reported that outcomes of anterior decompression/fusion for CSM with local kyphosis with an angle of 10°or more were equivalent to those of laminoplasty (LP) alone for the same pathology at follow-up in their series of 43 patients, and the recovery rates of the Japanese Orthopaedic Association (JOA) score were acceptable in both groups. In their series, the local kyphosis angle of the anterior decompression/fusion group at follow-up was still a mean of 9.2°, so the correction of the local kyphosis would appear to be somewhat mild.…”