Sunday, December 14, 2014

Extra Digits- What Happens After Treatment

Postaxial polydactyly is the medical term for an extra digit on the pinky side of the hand.  It is far and away the most common location for an extra digit.  It is much more commonly seen in African Americans compared to whites (the reverse is true with radial polydactyly- thumb side).  There is a definite inheritance pattern (typically autosomal dominant).  I have previously written about this on several occasions- read here. 

I find it interesting that most children with an extra finger next to the pinky are not treated by a hand surgeon.  The extra digits are routinely "tied- off" in the newborn nursery.  Rarely these children may be treated in the pediatrician's office or at an orthopedic surgeon's office.  And most of these kids do really well, although small signs of the extra digit remain years later.  However, this treatment is best for the small extra digit and not the fully formed digit which requires a more formal surgery.

There is a huge variety in how the extra finger may appear- from quite small to normally sized.  The position and development of the extra digit is also variable as noted in this excellent article in the medical literature.
This child has a fully formed extra digit next to his pinky.

Smaller (and a bit swollen) extra finger.

Another type of extra digit, this time coming off the small finger closer to the nail.

So, no matter whether the extra digits is "tied- off" in the newborn nursery, clipped in the clinic or treated with formal surgery, most patients do great. 
Subtle hint of where the extra digit was removed.

However problems do develop.

1) One potential problem with an extra digit procedure is the need for a later surgery, a formal surgery to address the scar or pain.  In a recent article on using clips in the clinic (see here), 7% of kids needed a scar revision surgery.  Here is an example of a child treated in the nursery with an uncomfortable residual "nubbin."
Painful, small nubbin after treatment of polydactyly.
2) When the extra finger is clipped or tied, the blood supply to the digit is cut off and the extra digit enlarges, turns black and eventually falls off.  However, the timing of this process is unclear and the extra digit can stay on for week.  There is also a risk of infection.  These factors affect family satisfaction with this type of procedure and it certainly makes education of the family very important.

Necrotic extra digit after being tied off.

Another necrotic small finger polydactyly after being tied off.
3) Even formal surgery is not perfect for polydactyly.  The goal with formal surgery is to remove the finger and address the nerves, arteries, and tendons to allow a satisfactory appearance and function. And it is usually successful.  There are few problems reported.  Here is one recent example of a patient I treated with a revision excision.  His first surgery had been elsewhere and the surgeon had left behind some bone and the nerve stump had become painful as well.
After incomplete extra finger excision.  The patient needed a revision surgery.

Charles A. Goldfarb, MD
My Bio at Washington University


  1. Has anyone (or should I say any parent) ever wanted to keep the extra fully formed digit? Especially if it is not aesthetically offensive (such as the 1st photo)?
    I think it would be neat to have a normal looking extra digit, although it would be annoying having to buy custom made gloves!

  2. Kelly,
    Thank you for the question. That has indeed happened in my practice (not often). But, as I recall, both patient came back early in their teenage years to request the surgery to remove the digit.

    This brings up an important question- when can a child make such a decision for himself/ herself (as some families wan this to be a decision for the child). And the answer, is likely older than we think. Teenage years most likely. So while I respect the wishes of all my parents, I do make sure they understand that if they want their child to make the decision on this (or anything, really), it will need to be in many years. For that reason, I discourage the 'waiting' whenever possible.

  3. What if the normal pinky next to the extra digit doesn't have a nail and is shorter? Can the surgeons transfer the nail from the extra digit to the real one?

    1. Hello,
      In this situation, both fingers are abnormal- making for a more complex situation. This is very unusual and I would certainly recommend seeing an experienced hand surgeon who regularly addresses this type of issue. We do not routinely transfer nails.