Lambdoid Synostosis

Testing and diagnosis of lambdoid synostosis typically involve a combination of physical examination, imaging studies, and in some cases, genetic testing to rule out associated syndromes. Early diagnosis is important for determining the severity of the condition and deciding on the appropriate treatment, such as surgery or other interventions.

1. Physical Examination

The first step in diagnosing lambdoid synostosis is a thorough physical exam conducted by a doctor, usually a paediatrician or a craniofacial specialist. The doctor will assess:

• Skull shape and symmetry: Flattening on one side of the back of the head, asymmetry, or abnormal head position (tilting or twisting).
• Facial features: Ear displacement or facial asymmetry that may indicate cranial differences.
• Head posture: Any signs of torticollis (twisted neck), which can sometimes occur with lambdoid synostosis.
• Palpation of sutures: The doctor will gently feel the skull for any ridges or areas of hardness that could indicate early suture fusion.

2. Imaging Studies

Imaging is crucial for confirming the diagnosis and assessing the severity of the synostosis. Commonly used imaging methods include:

• X-rays: X-ray imaging can show the premature fusion of the lambdoid suture. It may help visualize the skull shape and identify areas of fusion, although X-rays are less detailed compared to other imaging techniques.
• CT (Computed Tomography) Scan: A CT scan is the most commonly used imaging tool for diagnosing lambdoid synostosis. It provides detailed cross-sectional images of the skull and can clearly show the premature fusion of the lambdoid suture. It helps identify:
  • The extent of the suture fusion.
  • Any associated differences in the skull and brain.
  • Potential intracranial pressure (ICP) concerns.
  • The need for surgical intervention.
• MRI (Magnetic Resonance Imaging): An MRI is sometimes used to assess the brain’s development and structure, especially if there are concerns about increased intracranial pressure (ICP) or developmental delays. MRI can show how the skull shape differences might be affecting brain growth.

3. Genetic Testing

If lambdoid synostosis is suspected to be part of a genetic syndrome (e.g., Crouzon syndrome, Apert syndrome, or Saethre-Chotzen syndrome), genetic testing may be recommended to confirm the diagnosis. Genetic testing can help identify mutations in genes like FGFR2 or FGFR3, which are associated with these conditions.

• Genetic counselling may also be offered to families to understand the inheritance patterns, potential risks for future pregnancies, and the possibility of associated conditions.

4. Additional Evaluations

In cases where lambdoid synostosis is suspected to be part of a broader craniofacial syndrome, additional assessments may include:

• Ophthalmological evaluation: To check for any eye-related issues, such as strabismus (crossed eyes) or optic nerve problems.
• Audiological testing: Hearing tests to evaluate any hearing loss, which may occur with craniofacial conditions.
• Neurodevelopmental evaluation: To assess any delays in motor skills, cognitive development, or speech.

Differential Diagnosis

• Positional plagiocephaly: A common condition where the skull flattens from external pressure, such as lying on one side too much. Unlike lambdoid synostosis, positional plagiocephaly does not involve suture fusion and often improves gradually as the baby grows, becomes more mobile, and pressure on the flattened area is reduced. It can usually be diagnosed through physical examination, with imaging used when needed to rule out suture fusion.