title: The influence of cervical spine position on the three anterior endoscopic approaches to the craniovertebral junction: an imaging study.
abstract: BACKGROUND
  Three endoscopic anterior approaches, the transnasal, transoral, and transcervical approaches, are used for ventral lesions of the craniovertebral junction and have been compared regarding surgical working distances and approach angles. However, how the position of the cervical spine influences the depths of surgical corridors and approach angles for the three approaches has not been evaluated.
  
  
  OBJECTIVE
  To evaluate the depths of surgical corridors and the approach angles for the three endoscopic approaches, taking the influence of cervical spine position into account.
  
  
  METHODS
  A radiographic study comparing three anterior endoscopic approaches to the craniovertebral junction.
  
  
  METHODS
  Cervical extension and flexion radiographs for 34 patients and cross-sectional computed tomography scans for 30 additional patients were assessed.
  
  
  METHODS
  The depths of the surgical corridors and the approach angles for the three endoscopic approaches in the midsagittal planes.
  
  
  METHODS
  We determined the mean angles of the surgical trajectories for the endoscopic transoral and transcervical approaches on cervical extension and flexion radiographs. In addition, we measured the depths of the surgical corridors and the approach angles for the three approaches in the midsagittal plane.
  
  
  RESULTS
  The average depths of surgical corridors were as follows: endonasal, 93.65 mm; transoral, 85.27 mm; transcervical, 62.97 mm (in extension). The average approach angles were as follows: endonasal, 31.22°; transoral, 30.87°; transcervical, 36.58° (in extension).
  
  
  CONCLUSIONS
  The position of the cervical spine does not influence the surgical convenience of the endoscopic transnasal approach, but it can influence the endoscopic transoral and transcervical approaches, especially the latter. The endoscopic transcervical approach offers several advantages over the endoscopic transoral and endonasal approaches.
authors.affiliation: Department of Orthopaedic Surgery, The Second Affiliated Hospital of Wenzhou Medical College, 109 Xueyuan Xi Rd, Wenzhou, Zhejing 325027, China.
authors.forename: Zhong-Ke
authors.initials: ZK
authors.lastname: Lin
authors.affiliation: Department of Orthopaedic Surgery, The Second Affiliated Hospital of Wenzhou Medical College, 109 Xueyuan Xi Rd, Wenzhou, Zhejing 325027, China. Electronic address: spinechi@163.com.
authors.forename: Yong-Long
authors.initials: YL
authors.lastname: Chi
authors.affiliation: Department of Orthopaedic Surgery, The Second Affiliated Hospital of Wenzhou Medical College, 109 Xueyuan Xi Rd, Wenzhou, Zhejing 325027, China.
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Wang
authors.affiliation: Department of Orthopaedic Surgery, The Second Affiliated Hospital of Wenzhou Medical College, 109 Xueyuan Xi Rd, Wenzhou, Zhejing 325027, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Yu
authors.affiliation: Radiology Department, The Second Affiliated Hospital of Wenzhou Medical College, 109 Xueyuan Xi Rd, Wenzhou, Zhejing 325027, China.
authors.forename: Bi-Dong
authors.initials: BD
authors.lastname: Fang
authors.affiliation: Institute of Digitized Medicine, Wenzhou Medical College, Wenzhou University Town, Wenzhou, Zhejing 325035, China.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Wu
mesh_terms: D000328:Adult; D000368:Aged; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D001269:Atlanto-Occipital Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D011859:Radiography; D055815:Young Adult
keywords: Cervical spine position; Craniovertebral junction; Endoscopic methods; Radiography; Surgical methods