Biodegradable self-reinforced poly-L/DL-lactide plates and screws in bimaxillary orthognathic surgery: short term skeletal stability and material related failures
Pe. Haers et Hf. Sailer, Biodegradable self-reinforced poly-L/DL-lactide plates and screws in bimaxillary orthognathic surgery: short term skeletal stability and material related failures, J CRAN MAX, 26(6), 1998, pp. 363-372
Biodegradable self-reinforced poly-L/DL-lactide plates and screws were used
for osteosynthesis in 10 consecutive cases of bimaxillary procedures with
simultaneous genioplasties, without postoperative rigid intermaxillary fixa
tion. During surgery, data were gathered concerning failure of the osteosyn
thesis material. Clinical examination was carried out meekly until the sixt
h postoperative week, Cephalometric analysis of standardized cephalograms w
as performed to evaluate the short-term skeletal stability pattern, which w
as compared with similar reports in the Literature.
Six weeks postoperatively, all jams were clinically stable and there was no
clinical evidence of foreign body reactions. For the whole group (n=10), t
he mean maxillary advancement at point A was 2.9 mm with a mean postoperati
ve relapse of 0.0mm, The mean advancement at point B was 2.8mm with a mean
additional advancement postoperatively of 1.1 mm, The mean vertical surgica
l displacement at point A was directed inferiorly with a value of 1.8 mm an
d a relapse of -0.4mm, At point B the corresponding values were 1.9 mm and
-0.4 mm, In the Angle Class III group (n=4), the mean advancement at A mas
5.9 mm with an additional postoperative advancement of 0.3 mm, In the Angle
Class II group (n=6), mean advancement at point B was 4.0 mm, with an addi
tional postoperative advancement of 1.1 mm. In the group with short face de
formity (n=3), the mean inferior movement in ANS was 6.6 mm with a relapse
of -0.2 mm, At Menton the vertical surgical movement was 13.0 mm with a rel
apse of -0.2 mm.
None of the plates, which were bent at room temperature:, broke, The screw
heads broke or had an insufficient fit in the bone in 12 of 305 (3.9%) scre
ws.
It can be concluded that the tested system of biodegradable self-reinforced
poly-L/DL-lactide screws and plates has a small material-related failure r
ate, and that their application in orthognathic surgery leads to a predicta
ble short-term skeletal stability pattern which is comparable to the 'gold
standard' of titanium plates and screws.