title: Skeletal stability in bimaxillary orthognathic surgery: P(L/DL)LA-resorbable versus titanium osteofixation.
abstract: BACKGROUND
  One-year skeletal stability following bimaxillary orthognathic surgery was assessed by comparing poly(L-lactide-co-DL-lactide) to titanium osteofixation.
  
  
  METHODS
  Thirty patients underwent osteofixation with poly(L-lactide-co-DL-lactide) copolymer and 30 had 2.0-mm titanium-miniplate osteosyntheses. Lateral cephalograms were analyzed preoperatively, postoperatively, and at 1-year follow-up. Average +/- SD values were as follows in resorbable plate-osteosyntheses (number of cases/titanium controls): for maxillary advancement, 3.5 +/- 4.1 mm (n = 19)/5.4 +/- 3.5 mm (n = 21); setback, 2.8 +/- 3.7 mm (n = 9)/1.9 +/- 1.8 mm (n = 8); elongation, 4.2 +/- 3.6 mm (n = 18)/3.7 +/- 5.2 mm (n = 14); and intrusion, 1.9 +/- 1.7 mm (n = 12)/3.3 +/- 2.7 mm (n = 13); for mandibular advancement, 4.6 +/- 3.6 mm (n = 10)/6.3 +/- 8.8 mm (n = 18); setback, 7.5 +/- 8.3 mm (n = 20)/7.2 +/- 3.2 mm (n = 12); enlargement of the mandibular angle, 11.8 +/- 9.9 degrees (n = 19)/7.9 +/- 6.6 degrees (n = 21); and reduction, 4.5 +/- 3.2 degrees (n = 9)/6.3 +/- 6.6 degrees (n = 9).
  
  
  RESULTS
  Preoperative to postoperative landmark positions within the study and control groups differed highly significantly (p = 0.008, paired t test), yet the amount of operative movement was comparable between the study and control groups (p = 0.5, two-sided t test). Absolute instability at the advanced A-point was (study group/controls) 2.3 +/- 1.8/2.4 +/- 2 mm, setback was 2.3 +/- 1.9 mm/2.5 +/- 1.7 mm, elongation at the anterior nasal spine was 3.8 +/- 3.1 mm/3.1 +/- 3.6 mm, intrusion was 2.1 +/- 1.9 mm/2.2 +/- 1.5 mm, advancement instability at the B-point was 4.9 +/- 4.3 mm/5.1 +/- 8.2 mm, setback was 3.0 +/- 2 mm/1.7 +/- 2 mm, mandibular angle enlargement instability was 6.7 +/- 8.9 degrees/8.2 +/- 9.6 degrees, and angle narrowing was 6.8 +/- 5.2 degrees/4.2 +/- 5.9 degrees. Absolute postoperative instability did not differ significantly between the study and control groups (p = 0.6).
  
  
  CONCLUSIONS
  Resorbable osteofixation as tested proved to be as reliable as titanium, but as the study and control groups were not matched, the results have to be interpreted as preliminary. Resorbable materials permitted clinically faster occlusal and condylar settling than standard titanium osteosyntheses, as bone segments showed slight clinical mobility up to 6 weeks postoperatively.
authors.affiliation: Maxillofacial and Facial Plastic Surgery, J.-W. Goethe University Medical Center, Frankfurt am Main, Germany. c.landes@lycos.com
authors.forename: Constantin A
authors.initials: CA
authors.lastname: Landes
authors.forename: Alexander
authors.initials: A
authors.lastname: Ballon
mesh_terms: D020341:Absorbable Implants / Q000191:economics; D000293:Adolescent; D000328:Adult; D001672:Biocompatible Materials / Q000191:economics; D001860:Bone Plates / Q000191:economics; D001863:Bone Screws; D002508:Cephalometry; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D005549:Foreign-Body Reaction / Q000517:prevention & control; D006801:Humans; D019248:Jaw Fixation Techniques / Q000191:economics; D008297:Male; D008312:Malocclusion, Angle Class II / Q000601:surgery*; D008313:Malocclusion, Angle Class III / Q000601:surgery*; D019186:Mandibular Advancement / Q000191:economics / Q000379:methods*; D008437:Maxilla / Q000601:surgery*; D008875:Middle Aged; D010027:Osteotomy; D011091:Polyesters / Q000191:economics; D011183:Postoperative Complications / Q000517:prevention & control; D014025:Titanium / Q000191:economics; D016896:Treatment Outcome
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; C033616:poly(lactide); D014025:Titanium