Analiza przydatności badań mikro-CT w ocenie wyników leczenia eksperymentalnych ubytków trzonu kości udowej królika z zastosowaniem fosforanu trójwapniowego hydroksyapatytu

This paper focuses on analysing the usefulness of micro-CT scans in assessing the efficacy of hydroxyapatite tricalcium phosphate in the treatment of experimental femoral bone defects in rabbits. The tests were conducted on 12 male Termond White rabbits, which had previously undergone bilateral surgical interventions involving femoral bone diaphysis (shaft) performed under operating-theatre conditions. The bones were drilled with a 4 mm drill. All rabbits had their left femur defects left without filling, whereas the right femur defects were filled with 100 mg of hydroxyapatite tricalcium phosphate preparation. After 8 weeks, the animals were euthanized to take specimens of both femurs. Micro-CT scans were taken with a Skyscan 1174 (Bruker – SkyScan). The area examined was subjected to volume rendering to determine the following parameters: Vb [mm³] – total volume of the specimen, Vb₁ [mm³] – high-density fraction volume in the specimen, and Vb₂ [mm³] – low-density fraction volume in the specimen, calculated by the formula Vb₂ [mm³] = Vb – Vb₁. Subsequently, after appropriate preparation, the specimens were assessed histopathologically. The analysis of micro-CT scan results showed a statistically significant increase in the total volume (Vb) of the part of the femur filled with the bone substitute (B) compared to the control group (A), and an increase in the low-density fraction volume (Vb₂). The volume of high-density fraction tissue (Vb₁) showed no statistically significant difference between the groups. The histopathological assessment of the control-group specimens (A) showed that bone defects had been completely filled by osteoid tissue with an irregular, feathery structure, and the cortical layer exhibited a marrow-induced thickening. The specimens from group (B) showed amorphous masses of the bone-substitute preparation surrounded by callus formed concentrically around preparation particles.