Computed tomography and histological evaluation of xenogenic and biomimetic bone grafts in three-wall alveolar defects in minipigs

Objectives

This study aimed to compare the performance of a xenograft (XG) and a biomimetic synthetic graft (SG) in three-wall alveolar defects in minipigs by means of 3D computerised tomography and histology.

Materials and methods

Eight minipigs were used. A total of eight defects were created in the jaw of each animal, three of which were grafted with XGs, three with SGs, and two were left empty as a negative control. The allocation of the different grafts was randomised. Four animals were euthanised at 6 weeks and four at 12 weeks. The grafted volume was then measured by spiral computed tomography to assess volume preservation. Additionally, a histological analysis was performed in undecalcified samples by backscattered scanning electron microscopy and optical microscopy after Masson’s trichrome staining.

Results

A linear mixed-effects model was applied considering four fixed factors (bone graft type, regeneration time, anatomic position, and maxilla/mandible) and one random factor (animal). The SG exhibited significantly larger grafted volume (19%) than the XG. The anterior sites preserved better the grafted volume than the posterior ones. Finally, regeneration time had a positive effect on the grafted volume. Histological observations revealed excellent osseointegration and osteoconductive properties for both biomaterials. Some concavities found in the spheroidal morphologies of SGs were associated with osteoclastic resorption.

Conclusions

Both biomaterials met the requirements for bone grafting, i.e. biocompatibility, osseointegration, and osteoconduction. Granule morphology was identified as an important factor to ensure a good volume preservation.

Clinical relevance

Whereas both biomaterials showed excellent osteoconduction, SGs resulted in better volume preservation.

     

Lengthening of the lower limbs and correction of lumbar hyperlordosis in achondroplasia

The analysis of more than 500 elongations carried out over a period of 15 years has led to the development of a technique of elongation of limbs in which surgical trauma and operative risk have been reduced to a minimum since all of the surgical stages are performed percutaneously. This technique results in overall elongations of more than 30 cm in the lower limbs, which makes it highly effective in the correction of short stature (achondroplasia, osteochondrodysplasia, hypopituitarism, Turner's syndrome) and severe limb length discrepancy. The techniques are used for elongating tibiae and femora as well as the modifications required to decrease lumbar hyperlordosis after lengthening of the femur. A review of the results and complications of the latest series treated with this technique consists of 208 tibiae and 156 femura.