An implantable medical device is disclosed comprising a thermoplastic composite body having anterior, first lateral, second lateral, posterior, superior, and inferior surfaces, and at least one dense portion and at least one porous portion which are integrally formed. The at least one dense portion is formed of a first thermoplastic polymer matrix that is essentially non-porous, and which is continuous through a thickness dimension from the superior surface to the inferior surface. The at least one porous portion is formed of a porous thermoplastic polymer scaffold having a second thermoplastic polymer matrix which is continuous through the thickness dimension. A method for forming the thermoplastic composite body is disclosed comprising disposing a first powder mixture in a first portion of a mold, disposing a second powder mixture in a second portion of the mold, simultaneously molding the first powder mixture and the second powder mixture, and leaching porogen.