Anterior Odontoid Screw Osteosynthesis in Treatment of Type 2 Odontoid Fracture
Condition: Odontoid Fracture
MeSH terms: Fractures, Bone
Study type: Observational [Patient Registry]

Summary: 
      Odontoid fracture is a common fracture accounting for 10-15% of all cervical fractures. It
      occurs in bimodal fashion in elderly and young patients.

      The classification of Anderson and Alonzo provides a guide for prognosis . Type I and type
      III have a good rate of union, while type II has a poor prognosis due to poor blood supply.
      Hence, operative fixation is recommended to avoid non-union.

      Treatment options for type II include anterior odontoid screw fixation and posterior C1-C2
      fusion.Despite the excellent rates of bony union in posterior C1-C2 fusion, it is associated
      with higher morbidity, higher blood loss and significant limitation in the range of motion
      and rotation of the neck.the aim of the study Is to evaluate clinical and radiological
      outcome of anterior odontoid screw osteosynthesis in treatment of type 2 odontoid fracture.
    

Detailed description: 
      Preoperative evaluation:

      Full clinical Evaluation and management in trauma unit using Advanced Trauma Life Support
      protocols.

      Full neurological assessment and classification using American Spinal Injury Association
      score.

      Radiological assessment includes antero-posterior and lateral plain cervical radiograph and
      CT scan for all patients. MRI will be done neurological deficit

      Operative technique:

      Position:

      The patient is placed supine on the operating table and neck is positioned in extension so as
      to achieve optimum reduction. Intra-operative x-rays are obtained in the Antero_posterior and
      lateral planes.

      Incision:

      Longitudinal incision is made at the medial border of the sternomastoid muscle on the right
      side.The platysma is divided,and the fascia of the sternocleidomastoid is sharply incised
      along its medial border. Blunt dissection is used to expose the anterior surface of the
      spinal column at the midcervical level by opening natural planes medial to the carotid artery
      sheath and lateral to the trachea and esophagus.The fascia of the musculus longus colli is
      incised in the midline, and the muscle is elevated from the vertebra.Blunt dissection in the
      retropharyngeal space is used to open a tunnel in front of the vertebra to the C-2 level.

      A K-wire is inserted through the incision up to the inferior edge of C-2, under Image, and
      impacted into the inferior edge of C-2. A K wire is advanced carefully controlled with
      biplane fluoroscopy from the inferior anterior edge of C-2 through the body of C-2 to the
      odontoid till its apex. A cannulated drill pit is then used over the wire. The drilled hole
      is then tapped. The screw, selected based on the measured depth, is placed and tightened
      firmly monitored fluoroscopically. One screw is biomechanically sufficient for fixation. The
      wound is checked for hemostasis,and closure completed in layers over a suction drain.

      Post-operative care and follow up:

      Post-operative collar for 6 weeks. Follow up visits at 2 weeks,2,6,12 months.Clinical and
      neurological assessment will be done and cervical X-rays will be ordered at each follow up
      visit.

      Functional outcome will be evaluated by Association for the study of internal fixation(AO)
      neck pain and disability score postoperative and at 1 year follow up.

      CT scan will be done for all patients at 1 year to ensure bony union.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        All cases with type 2 odontoid fracture admitted to trauma unit assiut university hospital