Cranial plug including a lucent disk

A cranial plug, comprising:

• a cranial plug housing including a first end, a second end, a first lateral side, a second lateral side, an upper surface, a lower surface, continuous side walls extending between the upper surface and the lower surface, a central body member, and a perimeter member;
• the cranial plug housing including multiple chemically distinct materials, the central body member is made of a first material and the perimeter member is made of a second material, wherein the first material is a rigid sonolucent polymethyl methacrylate (PMMA) or rigid sonolucent cubic zirconium and the second material is flexible and is made of porous polyethylene, expanded polytetrafluoroethylene (EPTFE), silicon, high density porous polyethylene (HDPE), polymethyl methacrylate (PMMA), or polyether ether ketone (PEEK);
• the upper surface of the cranial plug housing including a window recess with an access hole that extends from the window recess to the lower surface, the window recess is defined by a recessed surface formed along the upper surface;
• and
• a window shaped and dimensioned for positioning within the window recess of the cranial plug housing.