Operative techniques in the fetal rabbit.

The development of fetal surgical techniques has made the antenatal correction of congenital defects possible. These techniques have evolved from trials with animal models, permitting increasingly sophisticated operations with low morbidity and mortality. Experimental models range from large animals offering longer gestations but with single pregnancies and high cost, to smaller animals offering multiple pregnancies at reduced cost but with shorter gestations. This paper describes operative techniques in the fetal rabbit and its advantages as a fetal surgical model. Experience with the pregnant rabbit has shown it to be a suitable surgical model for several reasons. Pregnancies are multiple, increasing cost effectiveness and permitting operation on up to eight fetuses per litter without fetal loss. Techniques that promote fetal survival include local housing of does several days prior to operation and preoperative sedation. Spontaneous mask ventilation provides ease of anesthetic administration and titration. Overall surgery is well tolerated with a low incidence of intraoperative complications. Rabbit models have been used in the study of transamniotic fetal feeding, abdominal wall defects, and wound healing. These techniques have resulted in postoperative fetal viability approaching 90%, with negligible maternal mortality in over 4000 fetal operations, thereby making the rabbit a manageable cost-effective model of fetal surgery.