title: [Effect of penetration of mini-plate lateral mass screws into facet joint on axial symptoms in cervical laminoplasty].
abstract: 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 < 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 > 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 > 0.05). The NDI of the multi-joint penetrated group was significantly higher than that of other 2 groups (P < 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 (Chi(2)=4.881, P=0.087).
  
  
  CONCLUSIONS
  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.
authors: Department of Orthopedics, West China Hospital, Sichuan University, Chengdu Sichuan, 610041, P.R.China.
authors: Hua
authors: H
authors: Chen
authors: Department of Orthopedics, West China Hospital, Sichuan University, Chengdu Sichuan, 610041, P.R.China.
authors: Hao
authors: H
authors: Liu
authors: Department of Orthopedics, West China Hospital, Sichuan University, Chengdu Sichuan, 610041, P.R.China.
authors: Tao
authors: T
authors: Li
authors: Department of Orthopedics, West China Hospital, Sichuan University, Chengdu Sichuan, 610041, P.R.China.
authors: Quan
authors: Q
authors: Gong
authors: Department of Orthopedics, West China Hospital, Sichuan University, Chengdu Sichuan, 610041, P.R.China.
authors: Yueming
authors: Y
authors: Song
authors: Department of Orthopedics, West China Hospital, Sichuan University, Chengdu Sichuan, 610041, P.R.China.
authors: Jiancheng
authors: J
authors: Zheng
authors: Department of Orthopedics, West China Hospital, Sichuan University, Chengdu Sichuan, 610041, P.R.China.
authors: Limin
authors: L
authors: Liu
authors: Department of Orthopedics, West China Hospital, Sichuan University, Chengdu Sichuan, 610041, P.R.China.
authors: Qingquan
authors: Q
authors: Kong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001860:Bone Plates; D001863:Bone Screws; D002574:Cervical Vertebrae / Q000601:surgery*; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000601:surgery; D007796:Laminectomy / Q000009:adverse effects / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000209:etiology; D011183:Postoperative Complications / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D013115:Spinal Canal / Q000601:surgery; D013130:Spinal Stenosis / Q000601:surgery*