The Comparison In Paraspinal Muscles After Cervical Open-door Laminoplasty

Objective : Cervical spondylotic myelopathy(CSM) is the common reason for non-traumatic paralysis in adults, the incidence of decompression in majority of people is more than 0.7%. The posterior decompression is the important surgical method in the treatment of CSM, with the decrease in the indication of the laminectomy, the laminoplasty is popular. Although the cervical open-door laminoplasty is widespread in the treatment of multilevel CSM, included by all kinds of methods, and the axial neck pain after laminoplasty remain to be the common complication, which is associated with the paraspinal muscles. After laminoplasty,cervical paraspinal muscles will change in some status, for example, physiology, biochemistry, pathology and so on. Cervical paraspinal muscles play an important role on the vitodynamics of head and neck, but there is few research on the cervical paraspinal muscles after cervical open-door laminoplasty. The aim of this study was to evaluate the function and status of the cervical paraspinal muscles after laminoplasty, such as the characteristics of the cervical paraspinal muscles structures, the range of motion(ROM), and the meyoelectrical activation of the paraspinal muscles.Methods: We followed up 107 CSM patients between September 2014 and February 2015, The age ranges from 36 to 67 years, mean 52 years; the duration ranges from 6 to 12 months, mean 7.3 months. In all patients, there are 32 men and 28 women. They have underwent four common cervical open-door laminoplasty, included by the traditional cervical open-door laminoplasty(group A), open-door laminoplasty together with preservation of the unilateral paraspinal muscle ligamentcomplex(group B), laminoplasty used by Centerpiece without spinous process and laminoplasty and laminectomy hybrid decompression(group D). We evaluated JOA, the recovery of JOA, the cross-sectional area of the dural sac preoperative and postoperative respectively. Further, all patients performed X-ray, CT and MRI preoperative and postoperative respectively. MRI showed the cross-sectional area of bilateral paraspinal muscles preoperative and postoperative respectively. We also evaluated the cervical ROM and the meyoelectrical activation of the cervical paraspinal muscles.The needle electromyogram was performed in C6 level, and we collected meyoelectrical activation of the cervical paraspinal muscles three times when the muscles were relax and tense respectively. The data was analyzed by SPSS 21.0.Results: 1?In four groups, the cervical JOA score was improved, and the recovery of JOA, cross-sectional area of the dural sac increased significantly after surgery. 2 ? As MRI showed, the average cross-sectional area of the cervical bilateral paraspinal muscles at C3/4, C4/5, C5/6 level after surgery were not the imbalance of distribution whether group A, group B or group C. The cross-sectional area of the cervical bilateral paraspinal muscles after surgery in group D were almost symmetrical. 3?In four groups, the all cervical ROM of them decreased postoperatively. 4?The presence of spontaneous activity of the cervical paraspinal muscles was detected in each group. The activity of bilateral paraspinal muscle were not balanced weather group A or group B, which is different with group C. The bilateral amplitude and polyphasicity of the MUP(motor unit potentials) parameters were similar, weather given for group A or group B, which is also different with group C. The duration in every group was same.Conclusion: 1?Three widespread open-door laminoplasties could achieve the satisfied clinical outcomes. Of these four laminoplasties, laminoplasty and laminectomy hybrid decompression may have better outcomes and less complications. In the the surgeries with the preservation of spinous process, the axial neck pain is similar, which is opposite between the group C and group D. We hypothesized the non-preservation of spinous process may be the important cause of the axial neck pain. 2?As the MRI showed, the left cross-sectional area of the cervical bilateral paraspinal muscles after surgery was less than the right side one.They were not the imbalance of distribution whether group A, group B or group C. The group C were almost symmetrical. The activity of bilateral paraspinal muscle were not balanced weather group A, group B or group C, which is different with group D. We hypothesized the symmetrical distribution of the cervical paraspinal muscles has certain relation with outcomes and complications, but the details of mechanism is needed to be further explored in subsequent studies.