Does Use of Rigid Fixation After Removing Distraction Osteogenesis Device Reduce the Relapse?
Condition: Cleft Palate; Maxillary Hypoplasia; Maxillary Retrognathism
MeSH terms: Cleft Palate; Retrognathia
Study type: Interventional
Phase: Phase 2

Summary: 
      patients were enrolled by the inclusion criteria and were undergo lefort 1 maxillary
      osteotomy. after the latency phase the distraction was done in anterior- posterior vector.
      patients were divided by randomized allocation in 2 groups. in group 1 the distractor was
      removed after consolation phase, and in group 2 fixation devices were placed immediately
      after removal of distractors. data regarding relapse were analyzed by lateral cephalogram
      X-ray taken in 3 different phases of the trial. change of occlusal plane and the "A point" of
      the cephalometric analysis were determined as reference point of the study.
    

Detailed description: 
      All patients were undergo maxillary Lefort 1 osteotomy with intra oral distractors
      bilaterally. The latency phase was considered 5 days for all of them. Distraction was done in
      the anterior- posterior vector with 1 mm/day rate. In group 1 distraction devices were
      removed after finishing distraction and a 3 months consolation, in group 2 fixation devices
      (4 L shaped miniplates with 16 screws) were placed immediately after removing distractors.

      The amount of horizontal and vertical relapse were determined in the "A point" 2 years after
      finishing distraction.

      By using lateral cephalogram X-ray as a raw data base, taken in 3 occasions: preoperatively,
      immediately after finishing consolation phase and removing distractor with placing fixation
      devices or without them and 2 years postoperatively in every subject. Relevant skeletal
      points were determined and digitized to evaluate 2-dimensional skeletal changes during and
      after surgery and to subsequently determine the amount of relapse. The same X-ray machine and
      settings were used for all cephalograms.Patients were stabilized in the lateral Cephalogram
      unit (Planmeca, ProMax, Helsinki-Finland) using Cephalostat. With the position of the
      patients with their head oriented at 90 degree angle to the X-Ray beam at a distance of 5ft
      from the tube. The jaws were in maximum intercuspation, tip of the tongue behind the upper
      incisor teeth and lips in relaxed position. The receptor (CR, Konica Minolta medical imaging,
      USA) was placed 15 inches from the head. This is a standard under which all cephalometric
      radiographs are taken. It ensures that radiographs, taken in different times, are directly
      comparable.

      Radiographic exposures were 60-80 Kvp, 10-15 mA, and 16-32 sec, and repeated for each case in
      three occasions.

      The radiographs were processed in laser readout processor special for mentioned CR system.
      PACS. A DICOM system used for saving and transferring the images.

      All Lateral cephalograms were traced by hand and digitized, superimposed and evaluated by the
      same examiner. The tracings were rechecked by another examiner.
    

Intervention name(s): mini plate
Intervention type(s): Device
Intervention description(s): in the intervention group, 4 L shaped titanium mini plates with 16 screws were fixed immediately after distraction phase and removal of distraction ossteogenesis to prevent the relapse after distraction
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: distraction osteogenesis; mini plate; Lefort 1 osteotomy