How can you tell if you've packed an open wound enough?

Follow the guidance of your surgeon.  In general, I would advise you to gently pack the wound until you feel moderate resistance.  The wound does not need to be packed tight. Ideally all the surfaces will make some contact with the dressing so that when the dressing is changed, it removes debris/nonviable tissue from the wound surfaces.

Thank you for your question.  Wound packing is performed by an experienced nurse or doctor, and they will have an understanding of the amount of packing needed to fill the cavity without putting excessive pressure on the surrounding tissue.

I'm sorry to hear that you are having to deal with that, but it does happen from time to time. I would say that that you want to put just enough packing in to the point that it seems like the cavity is lightly-filled. You do not need to force more in. The idea is to prevent the skin from healing over the site before it has a chance to fill in from the base of the wound upward. Best wishes.

Typically the packing is gently inserted down to the resistance of the musculofascial layer at the bottom og the wound. You will feel that and not be able to pack any deeper. This is a very thick and solid layer so you don't need to be fearful.