Expanding the Indications for the Modified Melbourne Technique: Posterior Vault Reconstruction for Secondary Craniosynostosis With a Persistent Occipital Defect After Encephalocele Repair.

INTRODUCTION: Occipital encephaloceles are rare neural tube defects characterized by herniation of intracranial contents through a posterior calvarial defect and are frequently associated with complex neurological and structural anomalies. While early surgical repair is essential, children with large occipital encephaloceles remain at risk for delayed sequelae, often necessitating staged craniofacial reconstruction. Among available reconstructive strategies, the Melbourne technique and its modified variants are established methods for posterior vault expansion in severe or late-presenting sagittal synostosis. However, to our knowledge, this technique has not previously been applied in the setting of a large posterior calvarial defect associated with an occipital encephalocele.

CASE PRESENTATION: We report the case of a female infant with a prenatally diagnosed large occipital encephalocele measuring 10×12 cm, associated with Chiari III malformation, posterior fossa hypoplasia, and mild ventriculomegaly. She underwent neonatal encephalocele resection and dural repair, followed by ventriculoperitoneal shunt placement. Over time, she developed secondary sagittal craniosynostosis and a persistent large posterior calvarial defect. At 28 months of age, she underwent posterior cranial vault remodeling using a modified Melbourne technique combined with split-thickness calvarial grafting to reconstruct an 9×8 cm occipital defect. The procedure achieved posterior vault expansion, restoration of cranial integrity, and correction of her scaphocephaly deformity.

CONCLUSION: This case highlights the evolving and multifactorial challenges associated with large occipital encephaloceles, and demonstrates a novel application of the modified Melbourne technique in the setting of secondary sagittal craniosynostosis, a large posterior vault defect, and Chiari III malformation.