Abstract Archives of the RSNA, 2003
Damian Dupuy MD, PRESENTER: Nothing to Disclose
Abstract:
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Purpose: To determine the effects of radiofrequency energy on the growth
plate in young rabbits for possible future clinical applications in
image-guided non-surgical epiphysiodesis
Methods and Materials: 21 8-week old New Zealand rabbits underwent either 21
gauge sham needle placement or RF electrode heating of the proximal tibial
growth plate under fluoroscopic guidance. RF was performed with an SMK
electrode (Radionics Inc, Burlington, MA) with a 5mm active tip for 2 minutes
maintaining the tip tempererature at 80 C. with an RF generator (Cosman
coagulator 1, Radionics Inc, Burlington, MA). K-wires were placed in the tibial
shafts of both legs as a marker for leg growth. Rabbit leg growth was measured
every 2 weeks for 10 weeks using PA radiographs of the lower extremities.
Animals were sacrificed at 10 weeks for imaging and histologic analysis.
Imaging was performed with a uCT 40 (Scanco USA,Wayne, PA) (30u resolution) and
1mm helically acquired axial images with a multidetector CT (GE Light speed, GE
Medical Systems, Milwaukee, WI). Statistical analysis was performed with
parametric generalized estimating equations using GENMOD (SAS version 8.2).
Results: Two of the 21 animals died from dehydration due to diarrhea within the
first week after the procedure. Endpoint survival was achieved in 7 and 12
animals in the sham and RF group, respectively. 2 of the 12 animals in the RF
group were sacrificed at 4 weeks for early histological analysis. Measurements
of the entire and proximal tibial growth between the sham and RF group
demonstrated a statistically significant (p<.0001) reduction in proximal
tibial growth in the RF group by 1.9,3.1,4.4,6.6 and 8.4mm at 2,4 6,8 and 10
weeks, respectively. CT and micro CT analysis showed bridging bars of
trabecular bone that spanned the growth plate in the RF group. Histologic
analysis confirmed the presence of trabecular bone traversing the growth plate
in the RF group.
Conclusion: RF thermocoagulation of the growth plate creates bridging bars of
trabecular bone that significantly slows tibial growth in young rabbits. This
novel minimally invasive treatment may provide a means of epiphysiodesis in
humans with leg length discrepancies. This research was sponsored in part by a
small grant from Valley Labs (Boulder, CO). (D. D. is a consultant for and
received a grant from Valley lab.)
Questions about this event email: ddupuy@lifespan.org
Dupuy MD, D,
Image-guided Radiofrequency Epiphysiodesis of the Rabbit Tibia. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3103044.html