Constriction ring syndrome refers to a condition whereby fibrous bands from the lining of the uterus become entwined with the developing fetus during pregnancy. It occurs in approximately one in every 10,000 to 15,000 newborn babies. The condition is known by several different names including amniotic band syndrome, acrosyndactyly and amniotic band disruption sequence. The bands are always present at birth and are typically found wrapped around limbs, fingers or toes causing varying degrees of constriction. There is usually more than one constriction ring present.
What causes constriction ring syndrome?
The exact cause of the condition is unknown. It is not thought to be hereditary i.e. it is not passed down through families.
How serious is the condition?
Generally the deeper the constriction ring, the more problems it causes. Shallow superficial rings may cause nothing more than a slight circular indentation around your child’s fingers, toes or limbs. Deeper rings may impede blood flow/lymphatic drainage and result in significant swelling. These bands may also interfere with the normal development of the affected part of the body. If the rings are tight enough they may even cause the amputation of fingers or toes during pregnancy. Sometimes the rings can bind fingers or toes together at their tips. This is called acrosyndactly (see acrosyndactly in the syndactyly section)
How is constriction ring syndrome diagnosed?
The condition may be detected before birth through antenatal scans. The condition is always present at birth. X-rays may also be used to assess the depth and severity of the constriction rings.
How is the condition treated?
Treatment depends upon the severity of the constriction rings. Very shallow or incomplete rings may not require any treatment at all. If the rings have caused your child’s fingers or toes to be joined together (acrosyndcytyly) then a separation may be advisable between 6 months and 1 year of age to prevent problems with growth. Deeper individual rings are usually corrected when your child is at least one. The treatment is always tailored to your child’s needs. The aims are to optimise their hand function and appearance.
What does the surgery involves?
The surgery is usually carried out under a general anaesthetic. Correction of a constriction ring typically involves removal of the abnormal tissue on either side and at the base of the ring and recontouring of the soft tissues. This reconstructive surgery always results in some form of scar but can significantly improve your child’s limb or finger contours.
If my child is missing fingers or thumbs as a result of the condition can new fingers be created?
In some cases when children have lost more than one finger or a thumb it may be possible to reconstruct these missing elements and create more function in their hand through a toe transfer. This is only applicable to certain severe cases (see toe to hand surgery section)
What is my child’s long-term prognosis?
Typically the affected hands and fingers function well in the long term. In more severe case surgery can improve appearance and overall hand function.