How long do septal extension and spreader grafts made of rib cartilage last?

Septal extension grafts to lengthen a shortened nose (which are also spreader grafts in most cases) can be created from either septal or rib cartilage.  If available, septal cartilage is my first choice.  There is very little chance of warping or resorption when placed in the appropriate position.  Your nose will have excellent strength in very little time but a direct blow to your nose will likely disrupt the surgical result much like a blow would alter a previously un operated nose.

cartilage is the ideal grafting material because there is no need for blood vessels to grow into the graft in order for it to survive.  The grafts should be permanent.  Resorption is rare.

In most cases, grafts from rib taken from one's own body are permanent.  However, the nose may still change overall despite the grafts persisting.  The grafts are strong and should be able to withstand light contact but they are not indestructible and would be susceptible to deformity from a high impact injury (just like a normal nose would).