Secondary Synostosis After Spring-Mediated Cranioplasty for Sagittal Synostosis.

ObjectiveTo evaluate the incidence and characteristics of secondary synostosis following spring-mediated cranioplasty (SMC) for nonsyndromic sagittal craniosynostosis.DesignRetrospective cohort study.SettingSingle tertiary pediatric hospital.Patients/ParticipantsTen patients with isolated sagittal craniosynostosis who underwent primary SMC between 2021 and 2023. Patients with syndromic diagnoses or prior cranial surgery were excluded.InterventionsSMC was performed using 2 to 3 stainless-steel springs following sagittal strip craniectomy. Springs were typically removed 3 to 4 months postoperatively. Follow-up included review of clinical photographs, radiographs, and operative records.Main Outcome MeasuresChange in cephalic index (CI) from preoperative to postoperative assessment and occurrence of secondary suture fusion, particularly coronal synostosis.ResultsMean age at surgery was 4 months (range, 3-6 months). Mean CI improved from 68.5 to 79 following expansion. Three patients (30%) developed left unicoronal synostosis (UCS) during the perioperative period prior to spring removal. One patient required secondary coronal suturectomy for significant frontal asymmetry, while 2 were observed without intervention.ConclusionsSecondary synostosis, particularly UCS, may represent an underrecognized sequela of SMC. Altered biomechanical forces or asymmetric cranial remodeling during distraction may contribute to this finding. Larger, multicenter studies with longitudinal imaging are warranted to determine incidence, risk factors, and preventive strategies.