What is Polydactyly?

Polydactyly, derived from "poly" meaning many and "dactylos" meaning fingers, is the most common congenital limb anomaly. It's characterized by an extra finger or toe, often due to improper development in the anterior-posterior direction of the limb bud. Polydactyly can occur alone (non-syndromic) or as part of a syndrome with other congenital anomalies (syndromic). Clinicians should assess newborns with polydactyly for associated syndromes. The condition is more frequent in the right hand than the left, upper limbs over lower limbs, and the left foot compared to the right. Proper diagnosis and management are crucial for optimal outcomes.

Types of Polydactyly

Preaxial Polydactyly: Preaxial or supernumerary polydactyly is a common type, with an extra finger at the base of the thumb or big toe. This condition is often seen in families with genetic syndromes.
Radial and Ulnar Polydactyly: Radial or ulnar polydactyly features an additional digit near the radius or ulna. These types are less common than preaxial polydactyly but still significant in the field of congenital limb anomalies.
Postaxial Polydactyly: Postaxial or central polydactyly involves the extra digit adjacent to one of the smaller fingers or toes. This type is usually more severe than preaxial polydactyly due to its location.
Tibial and Fibular Polydactyly: Tibial and fibular polydactyly occur near the tibia or fibula in the lower leg. These types are rare but important for understanding the full spectrum of polydactyly.

Causes of Polydactyly

Incidence and Genetics

Polydactyly affects approximately 1 in 500 newborns. It is usually inherited as an autosomal dominant trait. Most cases are isolated without any associated birth defects, but some forms may be linked to chromosomal abnormalities like Trisomy 13.

Diagnosis and Family History

To determine the cause and type of polydactyly, a physical examination and medical history are essential. Genetic counseling is recommended for families with a history of the condition.

Types Based on Location

The form of polydactyly depends on the location of the extra fingers: preaxial (thumb side), postaxial (little finger side), radial (near thumb), ulnar (near little finger), or tibial/fibular (near shinbone). Imaging tests like X-rays can help assess structure and position.

Surgical Intervention

Surgery is advised for symptomatic cases to improve function, reduce deformity, and achieve aesthetic satisfaction. It also prevents complications like muscle imbalance due to asymmetrical muscles around joints.

Surgical Goals and Techniques

The goal of reconstructive surgery is to remove extra fingers while preserving sensation and ensuring adequate blood flow for long-term survival of remaining digits. Proper surgical techniques are crucial for minimizing risks and achieving successful outcomes.

Treatment of Polydactyly

Surgical Ligation

Surgical ligation is a safe method to remove extra fingers in babies. The doctor ties a tight band around the base of the extra finger, cutting off its blood supply. After one or two weeks, the extra finger falls off. This process does not harm other fingers or affect blood flow. Medical staff will provide specific instructions to protect your baby's hand during and after the procedure. Surgical ligation is typically used only when there are no bones or connective tissues developing in the extra fingers.

Office Excision Procedure

Office excision is a procedure to remove extra fingers. The doctor numbs the area with an injection and uses a cauterizing device, like a pen-like probe, to seal the skin around the extra finger as they remove it. The baby feels no pain during the removal but may feel some discomfort from the injection. If the extra fingers are not connected by bone to the rest of the hand or foot, office excision is the only option.

Polydactyly Surgery

Polydactyly surgery is necessary when babies have extra fingers on both feet or if they are not suitable for other treatments. The type of surgery depends on the type of polydactyly and how developed the extra fingers are. Doctors usually recommend surgery around one year old and will explain the needed procedure and expected results.

Postoperative Care

Simple Polydactyly

Children with simple polydactyly usually experience mild pain. For mild pain, Tylenol or Motrin can be given. The incision site may become wet the next day. Children should avoid soaking their hands or feet in water or swimming for 2 weeks after surgery. Glue and stitches will fall off within 2 to 4 weeks post-surgery. Your child's doctor and staff will teach you how to care for the scar.

Complex Polydactyly

Your child might go home with a pin to help keep the bones together while they heal. A cast may be needed to protect the area and aid bone healing. The doctor might prescribe pain medication immediately after surgery. The pin stays in place or the cast remains until the doctor sees your child at a follow-up appointment. An X-ray of the fingers or toes may be required before removing the pin or cast to ensure healing.

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