A Unique Case of Pure Bilateral Lambdoid Craniosynostosis and Progression to Mercedes-Benz Syndrome Following Spring Cranioplasty

We report a case of a 3-month-old female with isolated bilateral lambdoid craniosynostosis treated by suturectomy with cranial springs, who later demonstrated unexpected sagittal fusion. The patient presented with bilateral lambdoid and mendosal fusion producing a distinctive posterior vault deformity. Springs placed at suturectomy were removed five months later. Segmented CT analysis revealed intracranial volume expansion from 727.4 cm³ pre-op to 1371.9 cm³ post-removal, with minimal blood loss and uncomplicated recovery. Post-removal imaging showed complete sagittal synostosis, suggesting either a delayed manifestation of Mercedes-Benz pattern synostosis or a mechanically induced secondary synostosis due to springs, warranting further investigation.