title: [Comparison of accuracy of pedicle screw placement in the thoracic spine using funnel technique and free hand technique].
abstract: OBJECTIVE
  To study the accuracy the pedicle screw placement in the thoracic spine using funnel technique and free hand technique.
  
  
  METHODS
  Eight cadavers including 5 males and 3 females were analysed. The age ranged from 57 to 82 years (mean 68 years). Cadawers were randomly assigned to one of two instrumentation groups. In four cadavers, "funnel technique" was used for screw placement. In the remaining four cadavers,free hand technique then was used. Success of pedicle screw placement was judged by CT scan. The rate of success of two ways was compared using statistic analysis.
  
  
  RESULTS
  Ninety-six screws were inserted by "funnel technique" and free hand technique respectively, 84 of "funnel technique" were successful, and 73 of free hand technique were successful. Significant differences were found between two ways (P < 0.05). Chanciness tresis occurred in "funnel technique" on 2 screws and free hand technique on 9 screws. There were significant differences in rates of chanciness tresis (P < 0.05).
  
  
  CONCLUSIONS
  Funnel technique is simple, safe and cost-effective alternative to any other thchnique for pedicle screw placement in thoracic spine,funnel technique is able to reduce the chance of critical injury of nerve root and dura.
authors.affiliation: Department of Orthopaedics, Third Hospital, Whenzhou Medicine College, Ruian 325200, Zhejiang, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Cheng-xuan
authors.initials: CX
authors.lastname: Tang
authors.forename: Guo-jing
authors.initials: GJ
authors.lastname: Yang
authors.forename: Bin-feng
authors.initials: BF
authors.lastname: Yu
authors.forename: Li-cheng
authors.initials: LC
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D005260:Female; D005593:Fracture Fixation, Internal / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013904:Thoracic Vertebrae / Q000601:surgery*