title: C1 lateral mass screw insertion caudally from C2 nerve root - An alternate method for insertion of C1 screws: A technical note and preliminary clinical results.
abstract: BACKGROUND
  C1 lateral mass screw was widely used for fixation of the upper cervical spine. However, massive bleeding from the C1-2 venous plexus is sometimes encountered. In this study, we proposed an alternate method for C1 lateral mass screw insertion, which involves insertion of the screws caudally from the C2 nerve root to reduce bleeding from C1-2 venous plexus.
  
  
  METHODS
  Seven patients with atlantoaxial lesions were included in this study. The mean age at surgery was 65.9 (34-82) years. The mean follow-up period was 23.1 (12-38) months. All patients underwent atlantoaxial fusion with C1 lateral mass screws, which were inserted caudally from the C2 nerve root. All screws were inserted using O-arm based navigation system. Operative time, blood loss, C2 nerve root injury and perioperative complications were investigated. The accuracy of C1 screws and bone union were evaluated using postoperative computed tomography.
  
  
  RESULTS
  A total of 13 C1 lateral mass screws were inserted using this method. The mean operative time was 224 (144-305) min. The mean blood loss was 209 (100-357) g. One perioperative complication was observed, which was recurrent laryngeal nerve palsy. There were no vertebral artery or spinal cord injuries. No case of massive bleeding from the C1-2 venous plexus was observed. One patient complained of postoperative occipital neuralgia, which disappeared in 2 weeks. No malposition of C1 lateral mass screws was observed on postoperative computed tomography. Bone union was observed in all patients.
  
  
  CONCLUSIONS
  The C1 lateral mass screw insertion caudally from the C2 nerve root may become an alternate method for insertion of C1 screws.
authors.affiliation: Department of Orthopedic Surgery, Tokyo Women's Medical University, Tokyo, Japan. Electronic address: keijiwadajp@yahoo.co.jp.
authors.forename: Keiji
authors.initials: K
authors.lastname: Wada
authors.affiliation: Department of Orthopedic Surgery, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Tamaki
authors.affiliation: Department of Orthopedic Surgery, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Yui
authors.affiliation: Department of Orthopedic Surgery, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Numaguchi
authors.affiliation: Department of Orthopedic Surgery, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Murata
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D015331:Cohort Studies; D005260:Female; D017102:Fracture Healing / Q000502:physiology; D006801:Humans; D007431:Intraoperative Complications / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000175:diagnosis / Q000209:etiology; D061646:Operative Time; D010147:Pain Measurement; D010149:Postoperative Pain / Q000503:physiopathology; D059348:Peripheral Nerve Injuries / Q000209:etiology / Q000517:prevention & control*; D011379:Prognosis; D016059:Range of Motion, Articular / Q000502:physiology; D018570:Risk Assessment; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods; D013127:Spinal Nerves