Thumb Web Space in Amniotic Band

Amniotic Constriction Band is a common condition which affects each child differently.  It can lead to syndactyly (joining of fingers), amputations, or deep bands which limit function.  It often affects more than one extremity (ie, hands and feet) making efforts to maximize function really important.  I have posted many times on amniotic band- those posts can be found HERE. 

The thumb web space (also know as thumb- index web space or first web space) is vital for function.  A wide, deep space allows large object grasp.  For example, we often hold a soda can in the first web space whereas we cannot hold it between the fingers. 

Normal large object grasp

If we do not have a nice thumb web space, we often need to use two hands to grab larger objects.  The web space is also limited if the fingers are short- this makes the web space more shallow.


In patients with a tight first web space, surgery often makes sense to maximize the depth and width of this space.  This improves function in a very clear way- making it a very satisfying surgery for patient, family, and surgeon! This can happen in various conditions of the child's hand including arthrogryposis, cerebral palsy, hand burns, small thumbs, and amniotic constriction band.  There are various ways to address this surgically but the basic idea is to deepen the space and thus widen the gap between the thumb and index finger.  This usually requires a flap of skin to be rotated and sometimes a skin graft.

These pictures are of a child with amniotic constriction band.  Note the shortened fingers and narrow first web space.

Amniotic constriction band with tight first web space and short digits

Amniotic constriction band with tight first web space and short digits

After discussions with the family on the option of surgery to deepen the web, the patient was taken to the operating room for rotation flap from the top of the hand to deepen the space.  It has been dramatically helpful even at 3 months after surgery.  He is using the hand more and can more easily grab objects.  Note the flap and large space.

Amniotic constriction band with tight first web space with flap deepening.

Amniotic constriction band with tight first web space with flap deepening.

This patient will be closely watched over the next few years.  The other option we have to increase function is to lengthen the thumb and potentially the index finger.  This serves to deepen the web also.  I have previously written about lengthening HERE.

Charles A. Goldfarb, MD
My Bio at Washington University
Email me: congenitalhand@wudosis.wustl.edu