Saturday, October 6, 2012

Severe Symbrachydactyly and Nubbins

Symbrachydactyly, as noted previously, http://congenitalhand.wustl.edu/2011/12/normal.html  means "short, webbed fingers."  The use of this label is clearly appropriate for some children who (brace yourself for this truth) have short and webbed fingers (i.e., a syndactyly).  The term symbrachydactyly has further meaning as it has implications for etiology (i.e., cause).

I believe symbrachydactyly occurs due to difficulties with the AER and the underlying mesoderm during development- please see previous description of limb development http://congenitalhand.wustl.edu/2012/10/limb-formation.html  If the AER is lost, limb outgrowth stops and there is a deficient limb.  The theory is that early loss (i.e., at 4-5 weeks of gestation) leads to a really short limb and later loss (i.e., at 6-7 weeks of gestation) leads to more subtle symbrachydactyly.  The following children would be considered to have a severe symbrachyactyly- at least the way I consider it.  We have shared our thoughts and experiences with this diagnosis in the Journal of Hand Surgery: http://www.ncbi.nlm.nih.gov/pubmed/17996776

Symbrachydactyly
Nubbins of symbrachydactyly


















Another example of severe symbrachydactyly
The "nubbins" on the end of the arm likely represent some remnant from the cells from development (from the apical ectodermal ridge).  The nubbins can be surprisingly well formed and often have fingernails.  Some families preserve and value the nubbins while others feel that the nubbins get in the way and can be difficult to keep clean.  When families request, the nubbins can be easily excised with a small surgery.  The nubbins certainly do not grow and removal, therefore, is reasonable because function of the nubbins will not get better with age.  I leave these decisions to the family.

Others believe severe symbrachydactyly really should be called a transverse arrest or congenital amputation of the limb.  I don't mind those terms but I happen to believe this is most likely a development issue (a malformation)- meaning that something went wrong during limb development, not after.

The above examples differ from less severe symbrachydactyly:
Short finger type of symbrachydactyly- short, webbed fingers.

Another short finger symbrachydactyly



4 comments:

  1. Hello Dr Goldfarb

    I really like your blog, it is very informative! Symbrachydactyly used to be classified as a Type II or atypical cleft hand (Sandzen's Classification) under the central clefts in the Type 1 (Failure of Formation) in Swanson's Classification. I know that Swanson's classification is far from perfect, but where would you classify Symbrachydactyly now?

    Best Regards
    Dr Mark van der Velde
    Plastic Surgery Consultant
    Red Cross Children's Hospital
    Congenital Hand Clinic
    Cape Town
    South Africa

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    1. Thanks so much for your comments. I agree that symbrachydactyly is difficult to classify. First, in the Swanson classification, I either place them in the Undergrowth category or the Transverse Deficiency Category (Type1- failure of formation, transverse). And second, I like Oberg, Tonkin and Manske newer classification a good deal. There is a separate Hand Plate (differentiated from entire extremity) and symbrachydactyly would fall into the Failure of Formation/ Differentiation- Proximal/ Distal Axis.

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    2. I have the same condition. I've had it since I was born and it has caused me nothing but trouble from bullies mostly. And as I aged I got arthritis in the fingers.

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    3. Thank you for writing and I am sorry to hear about the social side of this. Yes, bullies can be trouble but as families learn how to offer support and build the child's self- confidence, this sort of issue can be lessened (but probably never eliminated). Additionally, I have not heard or seen much about arthritis but helpful to learn that this is possible. Good luck!

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