Usefulness of Ultrasonography in follow-up evaluation after Ilizarov Procedure: Comparison with PlainRadiography

Lee, Jong Hoon; Jee, Sung Woo; Lee, Ho Won; Lee, Sung Moon; Kim, Jung Sik; Kim, Hong; Song, Kwang Soon; Cho, Kil Ho; Woo, Sung Ku

Abstract

PURPOSE: To compare the usefulness of ultrasonography in follow up evaluation after the Ilizarov procedurewith that of plain radiography.
MATERIALS AND METHODS
We analyzed ultrasound findings in twelve patients who hadundergone the Ilizarov procedure, and retrospectively compared the results with the findings of plain radiography.The procedure was performed due to post-traumatic limb deformity or non-union(nine of twelve patients), congenitalpseudoarthrosis(one case), sequelae of poliomyelitis(one case), and short stature(one case). The patients' meanage was 29 years ; eleven of twelve were male. Ten of twelve procedures were performed on the tibia and two on thefemur. After 7-10 days, distraction was initiated at a rate of 0.25mm four times a day. Ultrasonography wasperformed with a 5-10 MHz linear or convex transducer ; new bone formation was defined as dotted or linearechogenic foci within a hypoechoic distraction gap. Initial ultrasonographic examination was performed 2-4 weeksafter distraction, and the results were compared with those of plain radiography. Color Doppler imaging wasperformed in three cases.
RESULTS
On ultrasonograms, new bone formation was initially detected 18-29(mean, 23)days after distraction, and on plain radiographs, 37-58(mean, 45) days after this procedure ; ultrasonography thusdetected new bone formation at least three weeks earlier than did plain radiography. Complication after theIlizarov procedure were four cysts at the distraction site, and one pin site infection, as seen on ultrasonograms.None of these four cysts, the size of which was 12-22mm(mean, 17mm), was visible on plain radiographs. In one casein which a cyst was present, ultrasound-guided aspiration was performed. Color Doppler examination was performedin three of twelve patients, and in all three, periosteal vascularity at the edge of the distracted gap was seento be preserved.
CONCLUSION
After the Ilizarov bone lengthening procedure, ultrasound appears to be useful forfollow-up examination. New bone formation, as well as complications, can be detected earlier ; it can indicatewhether ultrasound-guided interventional procedure is required, and if combined with color Doppler study, is ableto detect the periosteal blood supply. Further evaluation of the clinical significance of preserved periostealblood supply seems however, to be needed.