Prosthetics Symbrachydactyly

Only a thumb. Amazing outcome!

A child with a single digit may have one of two primary diagnoses.  If there is a single digit
– most resembling a little finger, the diagnosis is likely ulnar deficiency
– most resembling a thumb, the diagnosis is symbrachydactyly

Other diagnoses affecting the fingers include amniotic band syndrome which typically affects the central digits and causes shortening of several digits with banding and possible scarring at the fingertips (fenestrated syndactyly).   Cleft hand also affects the central digits, most commonly causing an absent middle finger.  And, lastly, radial deficiency typically may cause a small or absent thumb.

Symbrachydactyly can present in multiple different ways- see my previous posts HERE.   In a patient with symbrachydactyly and only a thumb, the functional need is for a digit (post) to pinch against.  This post will make the hand the best possible helper hand for the normal opposite hand (the opposite hand is normal in symbrachydactyly).   Without this post, the function of the thumb, and therefore the hand, is limited.

This child is five years of age and was born with symbrachydactyly.  He had only a single digit, a thumb, on the left.  Because there was a reasonable soft tissue envelope at the index finger area, we elected to perform a nonvascularized toe graft.  The idea is to bring a phalanx from the foot and place it in the hand to lengthen the digit.  This is somewhat controversial as the phalanx may or may not grow after transfer.  I have previously blogged about it HERE. 

Here are a few pictures of this amazing child with symbrachydactyly.  The first set of pictures is before surgery and immediately after the toe transfer.

Symbrachydactyly with a soft tissue envelope but no bony support of the index finger

Symbrachydactyly with a soft tissue envelope but no bony support of the index finger

Symbrachydactyly after toe transfer.  The blue cap covers the pin stabilizing the transferred bone until healing.

Symbrachydactyly after toe transfer.  The blue cap covers the pin stabilizing the transferred bone until healing.

This next set of pictures is several years after surgery.  Note how good the index finger looks and how great a post it makes for the normal thumb.  The toe phalanx has clearly grown making a great finger!  The donor site is the 4th toe and it does not look great without the phalanx.  But, the foot causes no problems and the hand is better off after the surgery.

Symbrachydactyly post reconstruction of the index finger

Symbrachydactyly post reconstruction of the index finger

While the hand looks great with a longer index finger, the foot shows clear sign of the toe transfer.

Finally, here are two videos showing function.  The first demonstrates the dexterity of the thumb and reconstructed index finger after reconstruction.

The next video shows what a helpful prosthetic can do.  In this case, as the patient has tried to learn to ride his bike, he has struggled with only the thumb and index finger (later, these two digits will be enough for bike riding and most activities).  With a simple passive prosthetic, the fingers are essentially lengthened and riding the bike becomes no problem!  The prosthetic is great for riding but is not really worn at other times, especially given his overall outstanding function!

Please note: mom gave consent for me to include these videos and pictures.
Charles A. Goldfarb, MD

My Bio at Washington University

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