An anvil assembly for use with a circular surgical stapling device having a housing and venting means, in the form of vent holes, for venting the interior of the anvil assembly. The housing includes channeling means in the form of a plurality of longitudinally extending and radially spaced surface grooves...http://www.google.se/patents/US5522534?utm_source=gb-gplus-sharePatent US5522534 - Anvil for surgical stapler
