Odael Spadeto Junior

Sistemas osso-implante ex vivo utilizando haste intramedular polimérica para imobilização de fraturas femorais em bovinos jovens

The development of new devices using available and low cost materials may be an useful alternative for the treatment of long bone fractures in large animals. The aim of this study was to evaluate the mechanical strength of young bovine femur with diaphyseal fracture fixed with different polymeric intramedullary nails. Bending and compression tests using a universal machine were carried out in 4 distinct groups of 6 femurs from young calves. In one of the groups bones were intact while in the other three fractured bones were fixed using an intramedullary nail made of polypropylene, polyacetal or polyamide (one for each group). Considering bending and compression tests together, none of the used polymers offered strength to the fractured bones similar to the intact ones. The agreement of this findings with those from previous published in vivo results indicates that the employed ex vivo methods for mechanical assays may be useful in the search of stronger materials to be used in development of new devices.

Falhas na utilização de poliacetal e poliamida em forma de haste intramedular bloqueada para imobilização de fratura femural induzida em bovinos jovens

In spite of the expressive development of veterinary orthopedics in the last years, long bone fractures in large animals remains a challenge for veterinary surgeons. This study is part of a proposal for development of a low-cost and easy-to-use polymeric interlocking nail designed to be used in newborns and young cattle. The objectives were to evaluate, in vivo, polyacetal and polyamide nails for immobilization of femoral fractures in calves. Five calves were submitted to general anesthesia and the left femur was fractured and then fixed using polyacetal or polyamide rods (nails) interlocked with four cortical screws (stainless steel) equally applied to the distal and proximal fracture line. In the postoperative period, calves were clinically assessed during 60 days by clinical and radiographic exams. Fractures occurred in four of the five polyacetal nails implanted in the first time and in two of the four polyamide nails implanted after the polyacetal nail failures. All failures occurred in the first 14 days after implantation. No rejection signs against the polymers were observed. In conclusion, polyacetal and polyamide did not have enough resistance to be used as intramedullary interlocking nails in this system designed to promote early femoral fractures immobilization in young calves.

Modelo de indução de lesão no ligamento suspensório equino com utilização de punch para biópsia cutânea

The aim was to study a novel model of suspensory ligament (SL) lesion. Under general anesthesia, a punch for skin biopsy (0.6cm of diameter) was used to create a circular lesion in the middle of SL simultaneously in the four members of six horses. All horses recovered without any important complication. Clinical and ultrasonographic evaluations were made during the post operative period. During the first two weeks, edema changed from mild to discreet, and pain changed from discreet to none around the surgical site. The lesions were easily observed by ultrasonography 48h after surgery as a homogenous anechoic area representing a mean (± SEM) 33.5±5% of the SL area, and did not change size during the first two weeks (P=0.77). In conclusion, the proposed model was efficient to promote controlled and homogeneous lesions in the four SL simultaneously without causing important discomfort to the horses. Taking in account these findings together with the possibility of evaluation of the ligament biopsy previously to any treatment, this method may be useful especially in studies testing therapies for tissue repair.