Friday, December 13, 2013

Symbrachydactyly, now what?

I have posted on symbrachydactyly several times in the past.  http://congenitalhand.wustl.edu/search/label/Symbrachydactyly

There are, by different symbrachydactyly classifications, 7 types:

  1. short finger
  2. cleft type (thumb and small finger present)
  3. peromelic (nubbins)
  4. monodactyly (only the thumb present)
  5. wrist bones present (but nothing more distal)
  6. wrist bones absent (ie, arm ends at the end of the forearm)
  7. transforearm (amputation at mid forearm level)
Nubbins, one of the classic findings in symbrachydactyly, can be present with any of these except the short finger type.  All can be associated with Polands syndrome (partial breast muscle absence with or without breast abnormality and chest wall abnormality) but the short finger variety is most commonly associated.  A recent manuscript offered a classification for Poland syndrome and confirmed that the most common finding in the hand was either no anomaly or 5 fingers but limited motion/ length.  http://www.ncbi.nlm.nih.gov/pubmed/22955538

One of my patients has a severe cleft type (almost a monodactyly type) of symbrachydactyly.  This is the original x- ray appearance.
Symbrachydactyly xray, severe cleft ype.


We treated him years ago with lengthening of the 5th metacarpal to allow functional pinch.  For several years he did well but now is limited by an inability to bring the thumb to the small finger ray.  Please note that we did not correct the thumb (despite the triangular shaped bone) because the deformity was helpful.
Symbrachydactyly after lengthening.  Note the longer 5th metacarpal.

Symbrachydactyly after lengthening.

Symbrachydactyly on right, normal hand on left.

We have discussed options with family including a surgery on the the 5th metacarpal (the lengthened bone) to angle it towards the thumb.  However, we have all agreed to attempt to treat this without another surgery at this point.  We will create a "post" to lengthen the small finger further (occupational therapy and prosthetics) to assess whether this helps functionally.  If it does (stay tuned for pictures), a formal prosthetic can be constructed.


11 comments:

  1. Dr. Goldfarb- Thank you for your efforts with this blog, your posts are very interesting and informational. I have one basic question about Symbrachydactyly that I have not been able to answer through online research. For children born with less severe symbrachydactyly (i.e. with 4 undersized fingers that have relatively good movement and function, plus a normal, unaffected thumb), do those fingers grow post-birth? Obviously they are not going to "catch up" to the full-size fingers on the unaffected hand, but do they grow over the years in their own unique way? Any insight on this would be much appreciated, thank you again and all the best.

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    1. B1979, thank you for your comments and question. Synbrachydactyly of the variety you discuss (short- finger type) typically affects the middle phalanx first (brief anatomy review- the fingers are made of 3 phalanges- proximal, middle, and distal and the hand is made of the metacarpals). So a mild, short- finger type of symbrachydactyly would cause the fingers to be short due to a small or absent middle phalanx. Each of the phalanges has a growth plate and each grows independent of the other phalanges or the metacarpals.

      The bottom line is that the fingers should absolutely grow as the child grows. This will be "powered" by the growth of the phalanges that have growth plates and the metacarpals as well. In most short- finger type symbrachydactylies actually grow well as all 3 phalanges and the metacarpal grow.

      I hope this helps.

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  2. Very helpful, thank you for the quick reply and all the best.

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  4. My son has this condition. Does the overall hand and thumb appearance continue to grow or will it remain as the size at birth?

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    1. Your son's hand will absolutely grow and the proportions of the thumb to the hand should remain similar. With growth, the opportunity for balancing the hand and creating a post for pinch may become more clear. Good luck.

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  5. Hi doctor
    My daughter was born with 3 small fingers on her left hand her middle ring and pinkie and her hand is smaller than her right hand she does have full length on her thumb and index my question is why is that her hand is smaller than her right and how does this condition happen with there's no birth defects in both spouses immediate family

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    1. Hello. Thank you for the question. I can answer the last question regarding a lack of birth defects. There are two possibilities- one is that this is a 'random' or new genetic event (i.e., not a transmission from parents). Or, this could be a birth difference related to an error in limb development- this is what we believe happens in symbrachydactyly (related to blood flow). I hope that helps.

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  6. My husband has a very similar hand. Our two kids do not. A Facebook page for ectro notes that it was a 50-50 chance for them to have inherited this and a 1 in 4 chance their children will. Is this so? Also there are other children in our small town with this. How unusual is this? Rflynn@keuka. Edu

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    1. Becca,
      Thank you for the question. Symbrachydactyly is a spontaneous mutation and I would not expect any other family member to be affected. The FB post must not be separating symbrachydactyly from other potential causes (many) of ectrodactyly. I am not sure how the other children may be affected or if exactly the same.

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