Wound Healing 101

Surgery is an assault.  There’s no way around it.  We break through the strongest barrier in the human body (the skin), mess with something inside, and bring the edges of the barrier back together.  Then it has to heal.  If wound healing is impaired, the incision will stay open, all we do in surgery is make it easier for your body to do its thing.

The first step in wound healing is the clearing away of any debris / dead tissue.  As a surgeon, we want to leave as little dead or injured tissue behind as possible to expedite the process.  Sometimes we’ll operate just to remove all of the dead or infected stuff to jump-start healing, (debridement, incision & drainage).

Once the edges of the most superficial part of the wound (the epidermis) are clean and viable, your body starts to bridge the gap.  Within 48 hours, most wounds are epithelialized, meaning there is at least one layer of cells covering the wound.  This is why, ideally, surgical dressings are left on for 48 hours.  The thinking is that if the sterile environment of the operating room can be preserved until epithelialization has occurred, there is less chance for wound infection.

After the wound is sealed from the outside world, the rest of the healing process can take place in an aqueous (water-based) environment.  Some debridement is still taking place but scar formation is starting.  Scars are mostly collagen and the cells that make it (fibroblasts).  The first collagen that appears in the wound is very stiff but strong.  Over time, more flexible types of collagen move in.  The wound reaches maximum strength at 6 months but will continue to remodel for about a year.

What is normal for surgical wound healing:

First 48 hours (-ish) – some drainage, by this I mean you may need to change the dressing 3-4 times per day.  The drainage may look like red Kool-Aid (serosanguinous fluid) or pus or a mixture.  In very early wound healing, neutrophils (the cells that make up pus) are integral in clearing away debris.  A small amount of pus can be normal.

What to do:

  • Keep the wound covered (exceptions are wounds that are closed with glue).
  • Change the dressing if it is soiled or at least once a day (wait 48 hours to change it for the first time if you can).
    • A clean non-sterile dressing is better than an icky surgical one. So if the dressing is soiled, change it – even if it’s before the magic 48 hours.
    • You have bacteria all over your skin. We can’t help it and their presence is, for the most part, a good thing.  This means you will never achieve a sterile environment at home, and that you probably don’t need one, so don’t try too hard.  Clean is usually sufficient for dressings / solutions that come in contact with a surgical wound.
  • Keep the wound dry. Before epithelization has occurred, the outside world still has access to your innards.  Tap water may be fine for intact skin but it’s not so great for a fresh wound.  That said, if you accidentally splash something on it, or get thrown in the pool (for example), or need a little liquid to get the dressing off (see below); don’t freak out, it will still probably be fine.  Change the dressing and watch.
  • If the dressing sticks to the wound it can really hurt taking it off. Getting the dressing wet will help it let loose.  Use as little water or saline as possible.  It will be much less traumatic than ripping the thing off.

What is normal:

  • Weeping from the wound (the red Kool-Aid or yellowish clear fluid).
  • Some bleeding can be normal. Spurting, not normal; pouring onto the floor, not normal.
  • Pus in the wound – not draining all over the place, but a fluorescent yellow-green layer between the skin edges or on the dressing can be normal.
  • A lot of surgeries are done with small incisions these days.  There can still be a lot of dissection on the inside.  Bruising is blood spreading between tissue layers.  If you’ve ever taken the skin off a chicken, you notice it comes off without too much effort once you’re in the right plane.  We are built the same way.  Blood can find those planes and spread.  It doesn’t take much blood to make a really impressive bruise.  Usually all this is is ugly.

What to worry / call about:

  • Profuse bleeding.
  • Rapidly spreading redness. This is rare.   Aggressive infections can occur immediately after surgery.  If you notice redness spreading beyond the dressing, outline it with a pen / eyeliner / marker.  Check frequently to see if the redness has spread beyond the mark.  A little spreading is probably okay but a lot of spreading in a short time can be a big deal.  Again, rare.  This also hurts like a …
  • Pooling blood. A small amount of internal bleeding can cause a harmless but ugly bruise but if the area is getting darker and starting to become raised it may be more serious.  These are called hematomas and sometimes there’s not much to be done but watch, but if you’re worried, especially if you’re on blood thinners, give your office a call.
  • New symptoms. Everything should get gradually better as you get further from your procedure.  If you notice you are feeling worse (more pain, more redness, more drainage, new numbness etc.) that can mean something is wrong.

By about 48 hours – epithelialization is hopefully complete, i.e. your body has sealed the wound off from the outside world.  You know this has happened when the wound stops draining.  One day, you will change the dressing and it will come off clean.  Your wound is now epithelialized.  That layer may be fragile at first but it’s there.  At that point (in my opinion):

  • You can go without a dressing if you like. Continue to dress the wound if it’s more comfortable to have it dressed (laparoscopic belly button incisions rubbing on jeans), or if it opens or drains.  If you’re comfortable with the dressing off and it’s not making a mess of your clothes you can go without a dressing from here on out.
  • You may be able to shower. Epithelialization is sealing the internal wound off from the outside world.  Once it’s occurred, fluid can’t get out, therefore water can’t get in.  In my opinion, at this point patients can shower.  No baths, no hot-tubs, no lakes, no pools… you get the idea; no submerging the wound yet.  Just let the water run over it while you clean up the rest of you.  Pat dry and redress if desired.

As the scar forms and remodels it will go from really beefy red to lighter pink to white.  The entire process can take up to a year.  Scars will only ever be 70% as strong as un-incised skin and they’re prone to sunburn.  Put sunscreen on your scars (if not on all of you).

Hopefully this gives you a basic understanding of how we heal.  I believe in helping people understand what their body is doing so that they can plan their life based on physical milestones, not on an arbitrary period of time.  Your surgeon may feel differently.  As I’ve said before but have to say every time I write something like this – I am not YOUR doctor and can’t be responsible for how you use this information.  It is designed to be a starting place for building your personal postoperative plan.  Maybe it at least helps you know what to ask your doctor.

One final thing, it is ALWAYS better to call the office during the day, during the week.  You will then have a team of people at your disposal instead of just a single call-doctor.   That call-doctor may not know your case, may be dealing with numerous things at the same time, and cannot call in pain meds for you.  There is always someone on call but you will get better service if you utilize the entire team, during the day, during the week.

Reference:  Essentials of Surgery: Scientific Principles and Practice. LJ Greenfield, MW Mulholland, KT Oldham, GB Zelenock, KD Lillemoe, eds. Philadelphia: Lippincott-Raven, 1997.

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