Kj. Stewart et al., A quantitative analysis of the effect of insulin-like growth factor-1 infusion during mandibular distraction osteogenesis in rabbits, BR J PL SUR, 52(5), 1999, pp. 343-350
Aim. To quantify, by histomorphometry, the effects of local insulin-like gr
owth factor-1 (IGF-1) during mandibular distraction at various rates.
Methodology. Mature rabbits underwent bilateral mandibular corticotomy and
distraction lengthening. Recombinant IGF-1 was administered to two groups o
f rabbits via osmotic infusion pumps. Distraction regimes were as follows:
Group A, 1 mm/day for 15 days; Group B, as for A plus IGF-I; Group C, 3 mm/
day for 5 days; Group D, as for C plus IGF-1; and Group E, sham-operated co
ntrols. After a 28-day consolidation period, rabbits were sacrificed and bo
ne deposition quantified using DEXA scanning, three-point bending, histolog
ical examination and sampled for histomorphometric analysis.
Results. DEXA scanning and three-point bending failed to detect any effect
of distraction rate or of IGF-1 infusion. Histological and histomorphometri
c analysis suggested 1 mm/day to be the ideal distraction rate, as this was
associated with greater osteoblastic activity and consistent bony union. H
owever, IGF-1 infusion significantly enhanced osteoblastic activity at both
distraction rates and resulted in bony union when distraction was performe
d at 3 mm/day.
Conclusions. Distraction osteogenesis at a rate of 1 mm/day provides greate
r osteogenic stimulus than 3 mm/day Exogenous IGF-1 has a positive influenc
e on osteoblastic activity during distraction. Its effect is probably minim
ised by high levels of endogenous IGF-1.