Mid-to-long term efficacy of laminoplasty combined with pedicle screw correction and fusion in the treatment of multilevel compressed myelopathy accompanied with degenerative kyphosis of cervical spine

English Keywords:Multilevel compressed cervical myelopathy  Degenerative kyphosis  Pedicle screw  Cervical spinal cord anterior angle  Laminoplasty

English Abstract:

  【Abstract】 Objectives: To study the mid-to-long term efficacy of laminoplasty combined with pedicle screw correction and fusion in treating the patients with multilevel compressed myelopathy accompanied with degenerative kyphosis of cervical spine. Methods: 18 patients of multilevel compressed myelopathy accompanied with degenerative kyphosis of cervical spine treated with posterior approach of open door laminoplasty combined with pedicle screw correction and fusion in our Hospital between March 2008 and September 2019 were retrospectively studied. There were 11 males and 7 females, aged 52.3±8.1 years old. Before surgery, 5 patients were diagnosed with ossification of posterior longitudinal ligament(OPLL) combimed with chronical cervical myelopathy, and the other 13 were with cervical spondylotic myelopathy(CSM). The range of decompression levels was C3-C7 in 17 patients and C3-T1 in 1 patient, and the number of vertebrae fixed and fused was 3.8±1.0. 12 cases out of the total were exmined with cervical MRI on discharge(about 2 weeks after surgery); And 11 cases were followed up for 2.1-13.5 years(10.5±2.8 years). Cobb angle was measured on lateral cervical X-rays and cervical spinal cord anterior angle(CSCAA) and modified K-line were measured on MRI before operation and on discharge, and fusion condition and loss of kyphosis correction angle were evaluated on the X-rays at final follow-up. Visual analogue scale(VAS) and Japanese Orthopaedic Association(JOA) score were collected before operation and at final follow-up. Results: The local Cobb angle was recovered to 3.8°±8.0° lordosis at 2 weeks after surgery from the preoperative 6.6°±6.5° kyphosis significantly(P<0.01); And the C2-C7 Cobb angle of cervical spine changed to 5.8°±7.0° lordosis at 2 weeks after surgery from the preoperative 1.3°±9.4° lordosis(P＞0.05). Of the 12 cases examined with MRI on discharge, the mean local CSCAA was improved from the preoperative 11.1°±4.2° kyphosis to 1.3°±5.2° kyphosis at 2 weeks after surgery, with significant difference(P<0.01); And the mean C2-C7 CSCAA was changed from 6.5°±4.4° kyphosis before operation to 1.1°±6.3° lordosis at 2 weeks after surgery, with significant difference(P<0.01). 7 cases(39%) suffered from C5 palsy after surgery, and all recovered completely in 1-4 months after surgery. Of the 11 patients followed up for 10 years and more, lateral X-ray of cervical spine showed bony fusion in all the operated segments without loss of kyposis correction angle; And MRI showed no compression of spinal cord, and no loss of CSCAA on mid-sagittal images; JOA score was 8.0±2.8 before surgery and 15.6±0.9 at final follow up, with significant difference(P<0.01), and the mean recovery rate of JOA score was (83±14)%; Neck pain VAS was 2.2±3.0 before surgery and 1.1±1.2 at final follow-up, and there was no statistical difference in between(P>0.05). Conclusions: For the patients of multilevel compressed myelopathy accompanied with degenerative kyphosis of cervical spine, open door laminoplasty combined with pedicle screw correction and fusion can achieve a long term stable and effective improvement in spinal cord function.