Disease Description (Causes and Symptoms)
- Definition: Congenital hand anomalies refer to conditions in which the shape of the hand or fingers develops abnormally from the fetal period. Representative conditions include syndactyly (fusion of the toes or fingers), polydactyly (extra fingers), camptodactyly (curved fingers), trigger finger (especially the thumb), cleft hand (split hand), macrodactyly, and congenital amniotic band syndrome.
- Causes and pathophysiology: Genetic factors (approximately 20%), environmental factors (approximately 20%), and unknown causes (approximately 60%) have been reported. Abnormalities in finger differentiation (cell death and formation of spaces), which occurs at approximately 6–8 weeks of embryonic development, cause syndactyly, while duplication of developmental signals or errors in differentiation cause polydactyly. An amniotic band is a band of membrane surrounding the fetus that causes tissue defects and necrosis through compression.
- Main symptoms: Abnormalities in the number or shape of the fingers (extra or missing fingers), fusion between fingers, flexion deformity, functional limitations (difficulty gripping or performing fine movements), and cosmetic problems. Some anomalies appear bilaterally and symmetrically, and there may be a family history.
- Prevalence (based on the provided data): Congenital hand anomalies have been reported in approximately 2–4% of newborns. Data indicate an incidence of approximately 1/2,000 for syndactyly and approximately 1/400 for polydactyly (with differences depending on the type and location).
Treatment Methods
- Basic principles: The goals are to restore function and a normal appearance (cosmesis), and surgical correction is necessary in most cases. Long-term follow-up is important because additional correction may be needed during growth.
- Non-surgical management: Mild camptodactyly (when there is no functional impairment) may be observed. Physical therapy and orthoses (splints) may be attempted to relieve symptoms.
- Surgical treatment (main guidelines)
- Syndactyly: Skin incision and separation, with a flap or skin graft to cover the skin defect. Simple skin fusion is generally performed around 1 year of age (usually between 1 and 2 years), but surgery before 1 year of age is recommended when there is concern about impaired growth, such as fusion between the thumb and index finger or between the ring and little fingers. Complex cases require staged surgery.
- Polydactyly: An appendage consisting only of simple soft tissue can be excised under local treatment during the neonatal period; when bones or joints are connected, reconstruction after excision or a combination procedure (combining two digits into one) is required. It is generally performed around 12 months after birth.
- Camptodactyly/limb anomaly: If not severe, observation is appropriate; if severe, correction is performed with osteotomy and ligament surgery (usually after 4–6 years of age or when necessary).
- Congenital trigger thumb: Some cases may resolve spontaneously (especially mild cases). If persistent, surgical procedures such as tendon sheath release may be performed.
- Congenital amniotic band syndrome: Immediate surgery is required when compression of blood vessels, lymphatic vessels, or nerves threatens finger survival. In other cases, surgery is performed around 6 months of age to remove the band and treat associated injuries.
- Complex ligament grafting and corrective osteotomy: Surgery is recommended after 5 years of age, taking the child’s cooperation and skeletal maturity into consideration.
- Postoperative care: Suture removal at approximately 2 weeks, casting or immobilization for 3–4 weeks (if necessary), and care of the skin graft site (massage, splinting, and rehabilitation). There is a possibility of repeat surgery (remodeling or contracture with growth, etc.).
- Medications: Pain management and antibiotic use during surgery should follow standard surgical guidelines (individual prescriptions are required).
- Risks of complications: Scarring, contracture (re-fusion), infection, skin graft failure, nerve or blood vessel damage, functional limitations, and remodeling with growth.
Checklist Before an Outpatient Visit (Documents, Items to Prepare, and Medical-Interview Points)
- Items/documents to prepare:
- A list of currently used medications (including prescription drugs, over-the-counter medicines, and herbal medicines) and allergy history (especially anesthetic drugs)
- Birth records and prenatal ultrasound results (copies if possible)
- Family history (whether similar hand anomalies are present)
- Records of previous surgery, anesthesia, and hospitalization, as well as past photographs (hand photographs from early childhood can be useful for comparison)
- Records and photographs of recent symptom changes (functional decline, pain, skin changes, etc.) from multiple angles
- Main points the doctor may ask about during the consultation (it is helpful for the child or guardian to organize these in advance):
- When the abnormality was first noticed and when symptoms (function and pain) changed
- Whether there has been developmental delay (use of the hands)
- Whether the condition is bilateral and symmetrical, and whether other physical anomalies are present
- Family history and information about medication and environmental exposure during early pregnancy
Examples of General Questions to Ask the Doctor
- What level of functional and cosmetic result can be expected from this surgery?
- When should the surgery be performed, and why? Is there a reason the surgery needs to be done now?
- What are the risks of surgery (including anesthesia) and the possible complications?
- How long will rehabilitation (physical therapy) take after surgery, and how long will activity be restricted?
- How likely is additional surgery as the child grows?
Examples of Condition-Specific Questions
- If syndactyly is present (especially involving the thumb):
- “How could fusion between the thumb and index finger affect hand function or bone growth as the child grows? Why do you recommend surgery now?”
- If polydactyly is present (complex form on the thumb side):
- “How do you plan to preserve and reconstruct the bone, joint, and ligament structures of the extra thumb? How likely is it that one surgery will be sufficient?”