title: Intra-operative computer navigation guided cervical pedicle screw insertion in thirty-three complex cervical spine deformities.
abstract: BACKGROUND
  Cervical pedicle screw fixation is challenging due to the small osseous morphometrics and the close proximity of neurovascular elements. Computer navigation has been reported to improve the accuracy of pedicle screw placement. There are very few studies assessing its efficacy in the presence of deformity. Also cervical pedicle screw insertion in children has not been described before. We evaluated the safety and accuracy of Iso-C 3D-navigated pedicle screws in the deformed cervical spine.
  
  
  METHODS
  Thirty-three patients including 15 children formed the study group. One hundred and forty-five cervical pedicle screws were inserted using Iso-C 3D-based computer navigation in patients undergoing cervical spine stabilization for craniovertebral junction anomalies, cervico-thoracic deformities and cervical instabilities due to trauma, post-surgery and degenerative disorders. The accuracy and containment of screw placement was assessed from postoperative computerized tomography scans.
  
  
  RESULTS
  One hundred and thirty (89.7%) screws were well contained inside the pedicles. Nine (6.1%) Type A and six (4.2%) Type B pedicle breaches were observed. In 136 levels, the screws were inserted in the classical description of pedicle screw application and in nine deformed vertebra, the screws were inserted in a non-classical fashion, taking purchase of the best bone stock. None of them had a critical breach. No patient had any neurovascular complications.
  
  
  CONCLUSIONS
  Iso-C navigation improves the safety and accuracy of pedicle screw insertion and is not only successful in achieving secure pedicle fixation but also in identifying the best available bone stock for three-column bone fixation in altered anatomy. The advantages conferred by cervical pedicle screws can be extended to the pediatric population also.
authors.affiliation: Department of Orthopaedics, Traumatology and Spine Surgery, Ganga Hospital, 313, Mettupalayam Road, Coimbatore-641 043, India.
authors.forename: S
authors.initials: S
authors.lastname: Rajasekaran
authors.forename: P Rishi Mugesh
authors.initials: PR
authors.lastname: Kanna
authors.forename: T Ajoy Prasad
authors.initials: TA
authors.lastname: Shetty