Characterization of pseudarthrosis with ultrasound backscattered signals in rats.
OBJECTIVE
To propose a novel model of pseudarthrosis in a small animal and to investigate the ability of backscatter parameters from ultrasound signals in differentiating normal bone from those ones with pseudarthrosis.


METHODS
Twelve Rattus norvegicus albinus free from pathogenic species (SPF) were randomly divided in two groups, with six animals each. In the Control group a surgical approach to the femur was made, followed by the synthesis of the muscle and skin layers. The Experimental group was submitted to an osteotomy of the femur and a vascularized flap of the fascia lata was interposed in the line of the fractured bone. Then the alignment and bone stabilization were accomplished, by using nylon stitch in U shape introduced in holes made in the proximal and distal fractured bone. Bone samples were scanned with ultrasound and signals were collected for each one to analyze the parameter Apparent Integrated Backscatter - AIB.


RESULTS
Radiological and anatomopathologic studies revealed the absence of bone consolidation with persistence of fiber-osteoid tissue. Values of the ultrasound parameter AIB from normal bones were statistically different from those with pseudarthrosis.


CONCLUSIONS
The experimental model was suitable for pseudarthrosis development in rats and the ultrasound backscatter parameters were able to identify such a bone disease in vitro.
Ferreira
Manoel Luiz
ML
Department of Surgery, Faculty of Medicine, UFRJ, Rio de Janeiro, Brazil. louiz_25@yahoo.com.br
Matusin
Daniel Patterson
DP
Machado
Christiano Bittencourt
CB
Silva
Paulo César
PC
Mello
Natalia Bernades
NB
Amaral
Alessandra Cintra
AC
Franco
Renata Schueler
RS
Pereira
Wagner Coelho de Albuquerque
WC
Schanaider
Alberto
A
D000818:Animals; D004195:Disease Models, Animal; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery; D011542:Pseudarthrosis / Q000000981:diagnostic imaging*; D011897:Random Allocation; D051381:Rats; D018709:Statistics, Nonparametric; D014463:Ultrasonography