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Unicoronal Craniosynostosis
Unicoronal craniosynostosis is a type of nonsyndromic craniosynostosis and occurs when one of the two coronal sutures fuses before birth. The coronal sutures run from the front fontanelle down to the side of the forehead.
Anterior plagiocephaly is always due to unicoronal synostosis. Female to male ratio is 68%. Unicoronal synostosis produces regional growth restriction and compensatory expansion of adjacent regions and obvious fronto-orbital dysmorphology 1)
Deraje V, Gopal S, Mendonca DA, Gujjalanavar RS. Endoscope-Assisted “Extended” Suturectomy for Unicoronal Craniosynostosis: A Technical Note. Plast Reconstr Surg. 2021 Oct 26. doi: 10.1097/PRS.0000000000008531. Epub ahead of print. PMID: 34705741.
Unicoronal Craniosynostosis: Classification
Unicoronal craniosynostosis is a non-syndromic or syndromic form of anterior craniosynostosis, caused by premature fusion of one coronal suture (left or right). It leads to anterior plagiocephaly.
🔍 By Laterality
- Left unicoronal craniosynostosis – fusion of the left coronal suture
- Right unicoronal craniosynostosis – fusion of the right coronal suture
🧬 By Etiology
- Non-syndromic (most common)
- Isolated fusion without associated genetic syndromes
- Typically unilateral
- Syndromic
- Associated with genetic disorders, often bilateral
- Examples:
- Crouzon syndrome
- Apert syndrome
- Muenke syndrome
- Saethre-Chotzen syndrome
🧠 By Morphological Pattern
- Anterior plagiocephaly
- Ipsilateral frontal flattening
- Retrusion of the supraorbital ridge
- Nasal root deviation
- Contralateral frontal bossing
- Vertical dystopia and orbital asymmetry
🏷️ By Clinical Severity (subjective)
- Mild – subtle asymmetry, primarily aesthetic
- Moderate – noticeable orbital/facial distortion
- Severe – marked asymmetry, functional compromise (e.g., vision)
📊 By Age at Diagnosis
- Early (<6 months) – better surgical remodeling outcomes
- Late (>12 months) – more rigid skull, possible compensations
🧪 Radiological Criteria
- CT scan shows:
- Premature fusion of one coronal suture
- Open anterior fontanelle
- Normal or patent other sutures
- Orbital asymmetry on 3D reconstruction
Treatment of Unicoronal Craniosynostosis
Unicoronal craniosynostosis, which leads to anterior plagiocephaly, is primarily treated through surgery. The main goal is to correct the craniofacial deformity and prevent long-term cosmetic and developmental issues.
🛠️ Main Treatment
Fronto-orbital Advancement Surgery
This is the standard surgical procedure, typically performed between 6 and 12 months of age.
Key steps include:
- Fronto-parietal craniectomy to remove the fused coronal suture
- Bilateral fronto-orbital advancement to reposition the orbital rim
- Bone remodeling on the surgical bench to achieve symmetry
- Radial osteotomies in the parietal and temporal bones for anatomical adaptation
- Fixation with resorbable plates and screws
- Reinsertion of the temporal muscle
- Layered closure and placement of a drainage system
Timing is crucial: the skull is still malleable, and brain growth demands expansion.
🔄 Alternative Options
Endoscopic-Assisted Surgery
- Indicated only if diagnosed before 3–4 months of age
- Minimally invasive
- Requires postoperative helmet therapy for several months
Helmet Therapy Alone
- Only effective for positional plagiocephaly
- Not effective for unicoronal craniosynostosis due to the fixed bony fusion
🎯 Treatment Objectives
- Correct facial and orbital asymmetry
- Prevent functional complications (visual, neurodevelopmental)
- Improve aesthetic appearance
- Preserve normal brain development
👀 Postoperative Follow-up
- Clinical and photographic assessments
- CT scan or 3D imaging if needed
- Neurodevelopmental evaluations
- Monitoring of scar and cranial shape