My interpretation of these wounds, as they are defined in texts, is that a new surgical wound of primary intention should become approximated (being joined by bond, strips, staples, or sutures) and exhibit a “healing ridge” by around post op day 5. It should not be necessary (nor do I believe is it desirable) to obtain a depth on these wounds. To probe the wound for depth is to potentially disrupt the joining of fascia, skin and tissue matrices, etc. If an area of the wound is showing signs of dehiscence after this 5 day period, there is an area of slough or eschar, or it’s not showing signs of remaining approximated, you may want to get a depth with your measurement. Also look to the peri-wound- is there ridge development? Is the skin cool, pale, and edematous? or ecchymotic? or in some other way raising doubt that the wound is approximating normally? Is it draining a lot?
We already know a primary intention wound has depth- so unless an abnormality is developing, I don’t think this information is needed. Measure the length, call it a linear wound.