Perhaps. It depends on the age of the person having the fusion (the younger you are, the more growth that may be lost), the number of bones involved (the more fused, the more potential loss). On the other hand, correcting some deformities can modestly increase height. For some young children, some pediatric deformity surgeons will use "growing rods, " delaying fusion as long as possible. Ask your surgeon.
Yes depending on the. Age of the patient interms of chlildhood ages as well as the location and extent of the fusion in terms of number of levels it can limit the length of the spine.