title: Clinical application of a revised screw technique via the C1 posterior arch and lateral mass in the pediatric population.
abstract: OBJECTIVE
  Pediatric patients with insufficient height (≤4 mm) of the C1 posterior arch may restrict atlas screw placement via the posterior arch and lateral mass (PALM). For these patients, we modified this technique, called the 'pedicle exposure technique' (PET). We aimed to analyze the clinical feasibility and safety of the PET in the pediatric population.
  
  
  METHODS
  Twenty pediatric patients with atlantoaxial instability (AAI) were enrolled in this study. The average C1 posterior arch was 3.1 (2.5-3.9) mm on CT scan. All patients underwent the C1 PET and C2 pedicle screw fixation. The imaging was performed to evaluate the accuracy of screw placement and bony fusion.
  
  
  RESULTS
  Forty screws were inserted via C1 PALM using the PET. Venous plexus bleeding occurred in 1 patient and the internal wall of the C1 lateral mass was perforated in 1 patient. There were no perioperative neurological deficits or vertebral artery injury. Follow-up was performed in all 20 cases over a period ranging from 6 to 80 months. Bony union was seen within 3-6 months. At the final follow-up visit, 14 patients had experienced an improvement, while 6 had complete resolution of their neck pain. Myelopathy symptoms were improved in 9 patients with spinal compression.
  
  
  CONCLUSIONS
  The PET is an effective alternative for pediatric AAI when the height of the C1 posterior arch is <4 mm. Because of the higher screw entry point through the C1 posterior arch, there is effective biomechanical stability and less irritation of the venous plexus and C2 nerve root.
authors.affiliation: Department of Orthopedic Surgery, China-Japan Friendship Hospital, Beijing, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Yi
authors.forename: Liang
authors.initials: L
authors.lastname: Dong
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Tan
authors.forename: Wenjun
authors.initials: W
authors.lastname: Wang
authors.forename: Xiangsheng
authors.initials: X
authors.lastname: Tang
authors.forename: Feng
authors.initials: F
authors.lastname: Yang
authors.forename: Guangbo
authors.initials: G
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging* / Q000601:surgery*; D001863:Bone Screws / Q000639:trends*; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011159:Population Surveillance; D011859:Radiography