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/10.3171/CASE251019.