title: Hybrid Technique for Cervical Pedicle Screw Placement: Combination of Miniopen Surgery and Use of a Percutaneous Cannula System-Pilot Study.
abstract: METHODS
  Cadaver study and clinical application; a pilot study.
  
  
  OBJECTIVE
  To minimize muscle dissection and enhance accuracy of cervical pedicle screw (CPS) placement by using a percutaneous cannula system.
  
  
  BACKGROUND
  Many studies have reported that the most frequent misplacement of CPSs is breach of the lateral wall; thus, an easy technique for securing medial convergence is required. We developed a percutaneous cannula system for this purpose and report the results of a cadaver study and its clinical application.
  
  
  METHODS
  A cadaver study was conducted to confirm the possibility of this percutaneous technique in 5 specimens (50 CPSs, C3-C7). Then, the technique was applied in 8 patients (40 CPSs, C3-C7). The surgical technique was a hybrid of miniopen surgery and the use of percutaneous cannula system under lateral fluoroscopic guidance. Entry holes were made in the open field and a cannula was used for tapping and insertion of CPSs. A stiff pedicle probe through the cannula was used to locate the pedicle in the lateral mass.
  
  
  RESULTS
  In the cadaver study, there were 12 (24%) misplacements among 50 CPSs used. The hybrid technique was applied clinically in 4 traumatic, 2 degenerative, and 2 failed back surgery lesions. Thirty CPSs were inserted using the percutaneous cannula system and 10 were inserted using a cannula as a retractor. Misplacement occurred in 6.7% (n = 2) and 20% (n = 2) pedicles, respectively, and there were no symptomatic complications (total incidence, 10%). An additional incision for the cannula system can be made for 2-level CPS insertions.
  
  
  CONCLUSIONS
  Use of the percutaneous cannula system facilitated a secure convergence angle for CPS insertion without extending muscle dissection or shifting cervical alignment because of muscle retraction. Moreover, this system can be used for CPS insertion in bull-necked patients.
  
  
  METHODS
  3.
authors.affiliation: *Department of Neurosurgery, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea †Department of Neurosurgery, Donghae Dong-In Hospital, Donghae, Korea; and ‡Catholic Institute for Applied Anatomy/Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Moon-Kyu
authors.initials: MK
authors.lastname: Kim
authors.forename: Sung-Min
authors.initials: SM
authors.lastname: Cho
authors.forename: Seung-Hoon
authors.initials: SH
authors.lastname: You
authors.forename: In-Beom
authors.initials: IB
authors.lastname: Kim
authors.forename: Dai-Soon
authors.initials: DS
authors.lastname: Kwak
mesh_terms: D019567:Back Injuries / Q000601:surgery; D001863:Bone Screws; D002102:Cadaver; D057785:Catheters; D002574:Cervical Vertebrae / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D019060:Minimally Invasive Surgical Procedures / Q000295:instrumentation; D019637:Orthopedic Procedures / Q000295:instrumentation* / Q000379:methods*; D010865:Pilot Projects; D013122:Spinal Diseases / Q000601:surgery