Objective To investigate the effect of the penetration of mini-plate mass screws into facet joint on axial symptoms in cervical laminoplasty. Methods A retrospective analysis was made on the clinical data of 52 patients who underwent unilateral open-door cervical expansive laminoplasty fixed with Centerpiece mini-plate between September 2009 and December 2011. There were 42 males and 10 females, with a mean age of 61.2 years (range, 34-83 years). Seventeen patients exhibited simple degeneration cervical canal stenosis, 25 patients had multilevel cervical disc protrusion, and 10 patients had ossification of posterior longitudinal ligaments. Disease duration ranged 1-120 months (median, 11 months). The Japanese Orthopedic Association (JOA) score was used to assess neurological function, and JOA recovery rates were calculated. The visual analogue score (VAS) and the neck disability index (NDI) were used to evaluate the axial pain and neck daily activities. The axial symptoms and other complications were recorded. The cervical canal diameter, cervical curvature, cervical canal cross area, and open angle were measured according to the X-ray films, CT scans, and MRI scans. The postoperative CT three dimensional (3-D) reconstruction images were used to identify whether the screws penetrated into the facet joints. All the patients were divided into 3 groups according to involved facet joints: no joint penetrating group (no penetrated facet joint), oligo-joint penetrating group (one or two penetrated facet joints), and multi-joint penetrating group (three or more penetrated facet joints). Results Five patients suffered from C5 nerve palsy, and 2 patients had cerebrospinal fluid leakage. The follow-up time ranged 3-35 months (mean, 15.7 months). At the final follow-up, the JOA scores, NDI, cervical canal diameter, and cervical canal cross area were significantly improved when compared with preoperative ones (P lt; 0.05). At 1 week after operation, CT 3-D reconstruction showed that 16 patients had no penetrated facet joint, 23 patients had one or two penetrated facet joints, and 13 patients had three or more penetrated facet joints. There was no significant difference in age, gender, disease duration, operation time, intraoperative blood loss, and follow-up time among 3 groups (P gt; 0.05). And at the final follow-up, there was no significant difference in JOA score, VAS score, cervical curvature, cervical canal diameter, cervical canal cross area, the JOA recovery rates, and lamiae open angle among 3 groups (P gt; 0.05). The NDI of the multi-joint penetrated group was significantly higher than that of other 2 groups (P lt; 0.05). Axial pain occurred in 1 case of no penetrating group, in 4 cases of oligo-joint penetrating group, and in 5 cases of multi-joint penetrating group, showing no significant difference among 3 groups (χ2=4.881, P=0.087). Conclusion The penetrations of lateral mass screws into articular surface of facet joint may contribute to the axial symptoms after cervical laminoplasty. The risk of axial symptom raises accompany with increased penetrated facet joints.
Objective To determine the surgical indications for posterior expansive open-door laminoplasty (EOLP) extended to the C1 level. Methods Seventeen patients undergoing C3-7 or C2-7 open-door laminoplasty were included as the case group between September 2005 and January 2010, whose spinal cord injury symptoms were not alleviated or aggravated again because of the cervical stenosis at C1-4 level, and the causes of the surgery itself were eliminated, all of these patients underwent reoperation with decompress upward to C1 level. Fifteen patients with cervical stenosis who underwent C2-7 laminoplasty and C1 laminectomy were selected as the control group. There was no significant difference in gender, age, and disease duration between 2 groups (P gt; 0.05). The pre- and post-operative cervical curvature and spinal cord compression were evaluated according to the patients’ imaging data; the pre- and post-operative neurological recovery situation was evaluated by Japanese Orthopaedic Association (JOA) 17 score and spinal cord function Frankel grade; the neurological recovery rate (according to Hirabayashi et al. method) was used to assess the postoperative neurological recovery situation. Results In the case group, 8 patients underwent primary C3-7 laminoplasty. In 3 of these patients, there was a cervical stenosis at C1, 2 level, and discontinuous cerebrospinal fluid around the spinal cord was observed; 5 of them with a compression mass which diameter was exceed 7.0 mm in the C2-4 segments. The remaining 9 patients in the case group underwent primary C2-7 laminoplasty, and the diameter of the compression mass was exceed 7.0 mm in the C2-4 segments. In all 17 patients of the case group, reoperation was performed with the decompression range extended to the C1 level, and the follow-up time was 35-61 months with an average of 45.6 months. Cervical curvature: there were 11 cases of cervical lordosis, 4 cases of straight spine, and 2 cases of cervical kyphosis before operation; but after operation, 2 cases of cervical lordosis became straight spine and 1 straight case became kyphosis. The postoperative neurological improvement was excellent in 8 cases, good in 7, and fair in 2. In the control group, all the patients had a compression mass which anteroposterior diameter was exceed 7.0 mm in the C2-4 segments before operation. The follow-up time was 30-58 months with an average of 38.7 months. Cervical curvature: there were 13 cases of cervical lordosis and 2 cases of straight spine before operation; but after operation, 1 case of cervical lordosis became straight spine. The postoperative neurological improvement was excellent in 8 cases, good in 6, and fair in 1. No significant difference was found in the JOA score at pre- and post-operation between 2 groups (P gt; 0.05); however, there were significant differences (P lt; 0.05) in the JOA score between at last follow-up and at preoperation. Conclusion The initially surgical indications which can be used as a reference for EOLP extended to C1 are as follows:① Upper cervical (C1, 2) spinal stenosis: C1 posterior arch above the lower edge part of cerebrospinal fluid around the spinal cord signal is not continuous, and the anteroposterior diameter of the spinal canal actual is less than 8.0 mm as judgment standard. ②There is a huge compression at the lower edge of C2-4 vertebrae, and the most prominent part of the diameter is exceed 7.0 mm, which can not be removed through the anterior cervical surgery, or the operation is high-risk.