Finger and Hand Developmental Disorders in Ankara, Turkey

Finger and hand developmental disorders are congenital anomalies that prevent the normal development of the hand and fingers during the embryonic period. These disorders may appear in different forms such as fusion (syndactyly), extra digits (polydactyly), or missing digits (oligodactyly). Early diagnosis and appropriate intervention are important.

Genetic mutations occurring during embryonic development, environmental factors, or syndromic conditions are among the main causes of these disorders. Different levels of involvement may be seen in the bones, muscles, and tendons of the hand. In some cases, a family history is notable.

Diagnosis begins with a physical examination after birth, followed by radiological evaluations for a detailed assessment. If needed, advanced imaging and genetic analyses may be used to investigate the underlying cause. Accurate diagnosis is critical for shaping the treatment plan.

The treatment approach varies depending on the type and severity of the deformity. Surgical corrections, reconstructive procedures, and physical therapy protocols are effective in improving functional and aesthetic outcomes. Long-term follow-up with a multidisciplinary team is often required.

What Are Finger and Hand Developmental Disorders?

Finger and hand developmental disorders are congenital conditions in which the structural or functional development of the hand and fingers does not progress normally. They may present as missing fingers, fused fingers (syndactyly), extra fingers (polydactyly), or anomalies involving bones, muscles, and tendons. These conditions can range from mild aesthetic differences to severe functional losses affecting grasp and fine motor skills. Early diagnosis and appropriate surgical or rehabilitative treatment are important.

At what stage in pregnancy and why do hand anomalies and finger developmental disorders occur?

The formation of a baby’s hands is one of nature’s most fascinating and complex engineering processes. Around the fourth week of pregnancy, upper limb buds appear on the embryo’s body—structures smaller than a grain of rice. Over the next four weeks, by the eighth week, these buds rapidly and precisely differentiate into the shoulder, arm, elbow, forearm, wrist, and finally the fingers.

This development resembles a sculptor carving fingers out of a block of marble. In the beginning, the hand resembles a single “paddle” or “plate.” For fingers to form, the cells between the future fingers must undergo a planned and programmed process of cell death known as apoptosis. When these cells disappear, the spaces between the fingers open up and five separate digits emerge. Any genetic signaling error, vascular insufficiency, or external influence during this critical period between weeks 4 and 8 can disrupt or alter this “carving” process.

Parents—especially mothers—often ask “Why?” and may blame themselves: “Did I eat something wrong?” or “Was it because I was stressed?” Based on scientific evidence, the answer we provide is clear: most cases are sporadic and occur by chance. Yes, genetic inheritance can play a role in some cases, but most of the time these anomalies are not preventable. Certain factors during the first trimester may increase risk.

Risk factors include:

• Febrile infections
• Uncontrolled diabetes
• Radiation exposure
• Use of certain medications
• Smoking and alcohol consumption
• Vitamin deficiencies

However, in many cases no specific cause can be identified. Families should not carry a sense of guilt; focusing their energy on treatment and support is the healthiest approach. This difference is not the result of a mistake by the parents, but a biological variation.

Which modern classification systems and imaging techniques are used to diagnose hand anomalies?

Accurate treatment begins with accurate naming and classification. While older classifications relied mainly on external appearance, modern systems are more detailed and based on genetic and developmental foundations. Approaches such as the Oberg-Manske-Tonkin (OMT) system help identify the source of the problem and guide surgical strategy. As plastic surgeons, we assess the condition not only as a “shape problem” but also in terms of its underlying developmental cause.

We generally evaluate these anomalies under four main categories:

Classification groups include:

• Malformations
• Deformations
• Dysplasias
• Syndromic anomalies

Malformations occur when a structure is missing or formed incorrectly from the beginning—such as an absent finger or bone development defects. Deformations occur when the hand initially develops normally but becomes distorted by external forces in the womb, such as amniotic bands. Dysplasias involve cellular organization disorders, such as overgrowth. Syndromic anomalies are those associated with other systemic findings elsewhere in the body.

Physical examination provides valuable information, but we also need to evaluate underlying structures. Radiological imaging is essential to assess the bones, joint alignment, and especially growth plates (epiphyseal plates).

Imaging techniques used include:

• Plain X-ray radiography
• Computed tomography (CT)
• Magnetic resonance imaging (MRI)
• Ultrasonography

These tools allow us to measure bone angles, identify missing structures, and plan surgical transfers with millimetric precision.

What are syndactyly types and how is syndactyly surgery performed?

Syndactyly—fusion of the fingers—is one of the most common hand anomalies. From the outside, it may look like a simple condition where two fingers are joined. However, from a plastic surgeon’s perspective, it is a multilayered and strategic reconstruction process. The goal is not only to separate the fingers, but to ensure they remain functional and aesthetically pleasing for life.

Syndactyly cases vary by complexity.

Clinical types include:

• Simple syndactyly
• Complex syndactyly
• Complete syndactyly
• Incomplete syndactyly

In simple syndactyly, only the skin and soft tissue are fused. In complex syndactyly, adjacent finger bones or nail beds are also fused, which makes surgery more challenging. If fusion extends to the fingertip, it is complete; if it affects only part of the finger length, it is incomplete.

The most critical technical aspect is reconstructing the “web space” between the fingers. If fingers are separated with a straight cut, scar tissue may contract over time and pull the fingers downward, leading to contracture and limited motion. To prevent this, we use geometric techniques such as Z-plasty. The skin is cut in a zigzag pattern, and triangular flaps are interposed to lengthen the scar line and avoid a straight contractile scar.

Sometimes the available skin is insufficient to cover the newly exposed side surfaces of the fingers. In such cases, skin grafts are needed. These grafts are commonly harvested from the groin region in children.

Reasons the groin is preferred for grafting include:

• Color match
• Tissue quality
• Hidden scar location
• Adequate donor area

The scar remains concealed under underwear, and the skin quality is similar to palmar/hand skin.

Why is timing important in hand surgery, and when should syndactyly surgery be performed?

Timing is one of the most important strategic decisions in congenital hand surgery. In general, we aim to perform surgery between 6 months and 2 years of age—ideally well before school age. There are strong anatomical and developmental reasons for this window.

Anatomically, early intervention is critical when fingers of different lengths are fused—such as the ring and little finger, or the thumb and index finger. These fingers grow at different rates, and if they remain tethered, the longer finger may bend and develop bone curvature and joint deformities. Early separation helps prevent permanent damage.

From a developmental perspective, the brain’s adaptability plays a major role. As children begin to explore the world with their hands, the brain forms a “hand map.” If the anomaly is not corrected, the child may code the fused condition as normal.

Advantages of early surgery include:

• Support of motor development
• Prevention of bone deformities
• Improved brain adaptation
• Psychological protection

Restoring hand function before the child reaches the age of fine motor milestones—such as holding a pencil or buttoning clothes—supports both physical and psychosocial development.

How is the extra digit evaluated in polydactyly?

Polydactyly is the presence of an extra finger beyond the usual number and is relatively common. Families sometimes wonder whether it is “just a piece of skin” that can be tied off or simply removed. However, this approach is medically incorrect. Polydactyly is not merely an aesthetic issue; it is a complex anatomical variation that can affect the biomechanics of the hand.

The extra digit often shares the joint capsule, tendons, and ligaments of the adjacent finger. Therefore, deciding which digit should be removed and how to reconstruct and strengthen the remaining finger requires detailed evaluation. Polydactyly is generally seen in two main regions.

Types of polydactyly include:

• Preaxial polydactyly
• Postaxial polydactyly
• Central polydactyly

Preaxial polydactyly occurs on the thumb side. Since the thumb alone contributes about 50% of hand function, careful reconstruction is essential. Ligament repairs, bone corrections, and muscle transfers may be needed to avoid instability or the “zig-zag deformity,” where the thumb becomes weak and misaligned.

Postaxial polydactyly occurs on the little finger side. In some cases, the extra digit may be a small soft tissue appendage attached by a thin stalk, which can be treated more simply. However, if a fully developed bony digit is present, detailed joint reconstruction is still required. The goal is not only to reduce the number of digits to five, but also to ensure the remaining five function smoothly and strongly.

What is pollicization in treating thumb absence or hypoplasia?

Among congenital anomalies, thumb hypoplasia is one of the most concerning for families and one of the most sophisticated conditions to plan surgically. The thumb is central to grasping, holding, and manipulating objects. When the thumb is underdeveloped or absent (aplastic), the hand’s ability to grip is significantly reduced.

In mild cases, tendon transfers and ligament reinforcement can make an existing thumb more functional. However, when the thumb is severely underdeveloped, attached only by soft tissue, or absent, we may perform one of the most remarkable procedures in plastic surgery: pollicization.

Key stages of pollicization include:

• Preparation of the index finger
• Preservation of vessels and nerves
• Bone shortening
• Rotation and fixation
• Muscle transfer

Pollicization is the repositioning of the index finger so that it takes over the role of the thumb. During this procedure, the index finger is shortened, rotated, and transferred into the thumb position while preserving its nerves and blood supply. In its new position, it looks and functions like a thumb.

The success of this procedure depends not only on surgical technique but also on the brain’s ability to adapt, known as cortical plasticity. In children, the brain is so flexible that it begins to map the index finger as the “new thumb” shortly after surgery. Although this decision may seem radical to families at first, it can ultimately provide the child with functional independence.