Essential Medical Skills to Acquire: Part 2, Suturing, by Cynthia J. Koelker, MD

In Part 1 of Suturing I discussed several aspects of wound closure, including goals of treatment, common lacerations, alternate wound closure techniques, types of suture to purchase, wound cleansing, sterile field, needle size, proper instruments, correct suture placement, and aftercare.

In Part 2 of Suturing I will address common mistakes to avoid.

Wound closure is not rocket science
, and any adult of average intelligence can learn the basic techniques.  Anyone who has sutured has learned from their own mistakes and those of others.  The following advice will help you skip a few errors and should make you look like a professional.

Common Suturing Mistakes to Avoid

Diagonal sutures yield misalignment
, often with “dog ears” or leftover skin remaining on one side, which will cause a puckered appearance or open area at one end.  Make sure to align the edges well and place your sutures exactly perpendicular to the wound edge, aligning each stitch as you go.

Over-tightening yields inversion of sutures
, that is, the edges dip into the wound, which prevents proper healing.  The sutured wound may look great, but what you really have is intact skin butting against intact skin, which of course isn’t going to grow together.  You need to have raw edge against raw edge, preferably with these edges everted a little (tented outward a bit).  As the wound heals they will flatten out.  Eversion is best accomplished by making sure you suture to the full depth of the wound with stitches as far from the edge of the wound as the wound is deep.  If the wound is a quarter-inch deep, sutures should be placed a quarter-inch away from the wound on each side, yielding a distance twice that (or one half inch) from side to side.

Likewise, suturing uneven thicknesses together often yields overlapping skin edges
, which also will not heal together.  In this case the raw skin edge overlaps onto intact skin.  Take care to check each suture as you go for tension adequate to close the wound but not enough to overlap tissue edges.

Under-tightening yields loose sutures with a gaping suture line
.  Be sure to use the surgeon’s knot (a double loop) on the first throw (half knot) of each suture.  This prevents knot slippage, which is especially helpful with nylon suture.  Raw tissue must touch raw tissue for the body to bridge the gap quickly.  It’s not that a gaping wound won’t heal, it will just take longer and cause a wider scar.  Everting the edges a bit, a millimeter or two, helps prevent this problem.  

Superficial sutures result in poor healing
.  Your stitches may look great on the outside, but if the deep layers do not touch each other, they cannot grow together.  Make sure to close the laceration to the full depth of the wound.

Using large needles and/or suture material on fine skin yields needle-hole scars
.  On tender or facial skin, better to use multiple fine sutures (5-0 or 6-0) placed closely together than try to bridge the wound using fewer, larger sutures.

Using too fine of suture on areas of greater thickness or tension may yield stitches that pull through
.  Only use 5-0 on fine skin such as the face, fingers, or children’s skin.  Use 4-0 for most standard lacerations where the wound is just through the skin and/or where tension across the wound is minimal.  Use 3-0 for deeper lacerations into the subcutaneous tissue and/or where tension across the wound is greater, especially over large joints.

Leaving sutures in too long also results in needle/suture hole scars
.  On fine skin which is not under tension 3—5 days is sufficient.  Average lacerations not under tension require 5—7 days before removal.  Deeper wounds or skin under tension require 7—10 days, though up to 14 days is recommended if healing is in doubt.  In patients whose sutures are left in longer they typically become embedded in the healing skin, which makes them difficult to find and remove.  If you suture someone up, examine your work daily to get an idea of the rate of healing. This only takes a minute or two, and also helps diagnose infection early.  If in doubt whether it’s too soon to remove stitches, take out only one or two in a non-critical area and see if the suture line holds.  Sometimes doctors take out alternating stitches one day, then the rest a few days later if wound strength is in question.

Leaving infected sutures in results in needle/suture hole scars and delayed healing
.  Once a wound has pus coming out or begins to look red and swollen, all sutures should be removed.  The wound will heal better once the pus is rinsed out, though may well require oral antibiotics (cephalexin, trimethoprim-sulfamethoxazole, or amoxicillin-clavulanate are all good choices).  If the infection is caught very early, removing the stitches and applying a topical antibiotic such as bacitracin, Bactroban, or possibly Triple Antibiotic Ointment may be sufficient.  (Doctors seldom recommend the latter due to increased likelihood of allergic reaction, but if it’s all you have I’d use it.)  I have not used honey for this purpose, but it may work as well.

Sutures placed too close to the wound edge may pull through
.  Placing your sutures about an eighth to a fourth inch from the wound edge is about right – the deeper the stitch is, the wider it should be.  Better a bit too wide than too narrow.

Just as women can learn to make a dress by reading a book, you can learn to suture on your own.
  However, most people feel more comfortable if they’ve had professional supervision, at least to begin.  To this end I offer workshops several times per year where students can perfect their skills and receive professional instruction.  (See my web site for upcoming classes.)

In the next article I will discuss Splinting and Casting

About the Author: Cynthia J. Koelker, MD is SurvivalBlog’s Medical Editor, the author of the book Armageddon Medicine, and the editor of