Isolated bilateral lambdoid and sagittal synostosis associated with hydrocephalus and Chiari malformation treated with early endoscopic suture release: illustrative case

BACKGROUND Isolated bilateral lambdoid and sagittal synostosis (iBLSS) has been of particular interest as a special entity and is commonly associated with hydrocephalus and Chiari malformation type I (CM-I). The authors present the case of a 5-month-old female diagnosed with iBLSS, complicated by hydrocephalus and CM-I, and review the available literature. OBSERVATIONS At 5.5 months of age, the child underwent endoscopic release of the fused sagittal and bilateral lambdoid sutures. Follow-up at 5 years of age showed significant craniofacial improvement and resolution of the hydrocephalus and CM-I, which has not been previously reported in the literature. Literature review included 95 cases, with the most common association being CM-I, followed by hydrocephalus and increased intracranial pressure. The majority of patients underwent cranial vault release with or without foramen magnum decompression. LESSONS Endoscopic release is an effective approach for managing iBLSS and led to the resolution of hydrocephalus and CM-I in the present case. https://thejns.org/doi/abs/10.3171/CASE251019.