ABSTRACT
The optimal period of time between peripheral-nerve repair and initiation of limb
lengthening procedures has never been precisely determined. In the clinical setting,
the surgeon must decide how long the repaired nerves should be allowed to heal before
subjecting them to the forces created by the limb-lengthening process. The authors
designed a study to quantify and qualify the effects of different recovery periods
between initial nerve repair and subsequent limb-lengthening via distraction osteogenesis.
Forty-two Sprague-Dawley male rats were randomized in two different categories of
nerve repair: end-to-end and nerve grafts. At 4, 8 and 12 weeks after nerve reconstruction,
the femur was submitted to limb-lengthening at a rate of 1 mm/day (0.25 mm every 6
hr).
Sciatic Function Index (SFI) evaluation indicated that the impact of distraction was
detrimental in the grafted nerves, although they maintained their electrical and morphologic
properties at comparable levels to the non-distracted nerves. Nerves with direct coaptation
presented an overall superior regeneration pattern. The findings in end-to-end repairs
distracted at 8 weeks and those of grafted nerves at 12 weeks were comparable to those
in distracted normal nerves. The morphology of the distracted nerves appeared to be
more organized than that observed in the non-distracted nerves.
