ABSTRACT
The discipline of limb lengthening has undergone numerous advances over the last few
years. The neurologic complications surrounding this procedure are well established
and described in the clinical setting, and can be deleterious for the patients in
distraction osteogenesis protocols. The specific aims of the reported project were:
1) to determine the ability of IGF-I to enhance nerve regeneration in repaired nerves
that are subjected to distraction only 4 weeks after nerve repair, and 2) to determine
if a low dose of IGF-I applied at the time of the repair is neuroprotective to repaired
nerves at this early time window.
Forty adult male Sprague-Dawley rats were randomized into eight groups (n=5). Four
groups (Groups A to D) underwent distraction of the femoral bone following sciatic
nerve repair, and four groups served as controls (Groups E to H). Nerve reconstruction
was achieved by end-to-end nerve repair (four groups, two with distraction [A, B]
and two without [E, F]) and by interposition nerve grafting (four groups, two with
distraction [C, D] and two without distraction [G, H]). A low dose of IGF-I was administered
at the time of nerve microreconstruction. Distracted groups, despite the administration
of IGF-I, demonstrated no signs of nerve regeneration, as assessed by sciatic functional
index (SFI), electrophysiologic studies, and quantitative and qualitative histologic
studies. Non-distracted groups showed signs of nerve regeneration.
The 4-week time interval between nerve repair and distraction did not provide enough
time for nerve regeneration to be completed, even if the repair was exposed to a low
dose of IGF-1.
KEYWORDS
Limb lengthening - distraction osteogenesis - IGF-I
