J. Sanz et al., THE VIABILITY OF CRYOPRESERVED ONLAY CRANIAL BONE ALLOGRAFTS - A COMPARATIVE EXPERIMENTAL-STUDY VERSUS FRESH AUTOGRAFTS, Annals of plastic surgery, 36(4), 1996, pp. 370-379
It is well known that calvarial bone autografts are the bone grafts th
at are the least reabsorbant and have the best long-term evolution in
craniofacial surgery. However, they do have certain limitations: (1) r
eabsorption results in repeated surgery and the need for new donor are
as, (2) a limited amount of autogenous cranial bone is available (due
to avoiding areas close to cranial sutures and venous sinuses, and bec
ause the temporal bone is very fragile and the cranium has not fully d
eveloped in children), and (3) graft extraction increases surgical tim
e and morbidity. Because of this, we present an alternative to calvari
al bone autografts: cryopreserved allografts. This paper is an experim
ental prospective study carried out on sheep with the following goals:
(1) to assess the behavior of calvarial onlay bone grafts cryopreserv
ed at -80 degrees C, using fresh autografts implanted under the same c
onditions as controls; (2) to compare reabsorption percentages statist
ically over time; and (3) to study qualitatively any histological vari
ations, The results obtained are (1) more reabsorption of allografts w
hen compared to autografts (at 90 days, 21.97% versus 20.21% of grafte
d volume), although this difference is not statistically significant;
(2) a reduction in height in all onlay grafts as a consequence of the
loss of the diploe; (3) the absence of any type of inflammation caused
by a reaction to cryopreserved allografts; and (4) bone substitution
performed using frozen allografts is histologically similar to that us
ing fresh autografts.