Roentgen stereophotogrammetric short-term analysis of growth rate in children operated for Crohn's disease.

Roentgen stereophotogrammetry is a new method for short term analysis of growth rate. Growth is measured over the growth zone in the distal fibula and is a fraction of the total statural growth. Normal growth rate in the distal fibula is about 15 micrograms/day at a total growth rate of 5 cm/year. The method was used to follow growth six months before and six months after surgery in six growth retarded children with Crohn's disease. Growth rate increased significantly (p less than 0.01) within three months after surgery from 5.8 microns/day before operation to 15.8 microns/day three months after operation and six months postoperatively had reached 18.0 micron/day. Improved growth could be recorded as early as four weeks after operation. The Roentgen stereophotogrammetric analysis (RSA) gives a unique possibility to follow short-term changes in growth rate in children with disturbed growth and to use growth rate as a quick assessment of response.