title: Radiological Efficacy of Cervical Lateral Mass Screw Insertion and Rod Fixation by Modified Magerl's Method (Yoon's Method) with Minimum 2 Years of Follow-up.
abstract: OBJECTIVE
  Cervical lateral mass screw insertion and rod fixation is a useful method for stabilizing the cervical disease, so various modified techniques were present. Many surgeons had reported the biomechanical safety according to the screw positioning method in the cervical spine, but the modified Magerl's method (Yoon's method) was not well studied. So, this study assessed the radiological efficacy of the modified Magerl's method with long-term follow-up.
  
  
  METHODS
  This study retrospectively reviewed 323 lateral mass screws of 50 patients who had followed-up at least 2 years. Radiologic data were analyzed as parameters of complications after operation, including kyphotic or lordotic change, bone fusion, pull-out or malposition of screw, foraminal stenosis, adjacent disc degeneration or aggravation, pseudoarthrosis, and vertebral artery injury.
  
  
  RESULTS
  The mean follow-up period was 32 (24 to 52) months. There were kyphotic changes in 4.0%(2 of 50 cases). Unsuccessful bone fusion occurred in 4.0%(2 of 50 cases). Among the 323 screws, screw pull-out (4.0%. 2 of 50cases, 3 of 323 screws), foraminal invasion (1.2% of total screws), and facet injury (0.6% of total screws) occurred.
  
  
  CONCLUSIONS
  The lateral mass screw insertion and rod fixation by the modified Magerl's method (Yoon's method) is a safe and reliable technique with low rate of complication related to instruments in minimum 2 years follow-up.
authors.affiliation: Department of Neurosurgery, Inha University College of Medicine, Incheon, Korea.
authors.forename: Do Yeon
authors.initials: DY
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, The Armed Forces Hospital of Pusan, Korea.
authors.forename: Ji Yong
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Inha University College of Medicine, Incheon, Korea.
authors.forename: Seung Hwan
authors.initials: SH
authors.lastname: Yoon
authors.affiliation: Department of Neurosurgery, Inha University College of Medicine, Incheon, Korea.
authors.forename: Hyung Chun
authors.initials: HC
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, Inha University College of Medicine, Incheon, Korea.
authors.forename: Chong Oon
authors.initials: CO
authors.lastname: Park
keywords: Long-term follow-up; Modified Magerl's method; Radiological assessment; Spinal fusion; Yoon's method