Does anyone know what code I should use to report the placement of subgaleal siliastic sheet "spacer graft"? Does it bundles into the flap?

Provider documentation summary:

PROCEDURES:
Delayed paramedian forehead flap measuring 3.2 cm x 7 cm.
Split-thickness skin graft

** flap was elevated in the subgaleal plane
** skin graft was trimmed to size and secured to the distal flap
** silastic sheet was placed below the graft on the forehead, is a spacer graft.
** silastic sheet was then trimmed to size, placed in the forehead wound bed and the flap was laid back down and secured

I am thinking 15731 for the paramedian flap, 15120 for the skin graft but not sure about the siliastic placement

Thanks in advance…