Etiologies of [[secondary craniosynostosis]] include: metabolic (rickets, hyperthyroidism...), toxic (drugs such as [[phenytoin]], [[valproate]], [[methotrexate]]...), hematologic (sickle cell, [[thalassemia]]...) and structural (lack of brain growth due to e.g. [[microcephaly]], [[lissencephaly]], [[micropolygyria]]...). CSO is rarely associated with [[hydrocephalus]] (HCP) ((Golabi M, Edwards MSB, Ousterhout DK. Craniosynostosis and Hydrocephalus. Neurosurgery. 1987; 21:63–67)). ---- [[Craniosynostosis]] following placement of a [[ventriculoperitoneal shunt]] for [[hydrocephalus]] has been sporadically described. The purpose of an investigation by Bryant et al. was to determine the general risk of developing craniosynostosis in this patient population. The authors retrospectively reviewed records and radiographs of infants who underwent ventriculoperitoneal shunt placement for hydrocephalus from 2006 to 2012. Recorded variables included date of shunt placement, demographics, comorbidities, cause of hydrocephalus, shunt type, and the number of shunt revisions. Axial computed tomographic images obtained before and immediately after shunt placement and 2 to 4 years after shunt placement were evaluated by a panel of clinicians for evidence of craniosynostosis. Patients with preshunt craniosynostosis, craniosynostosis syndromes, or poor-quality computed tomographic images were excluded. Data were analyzed using STATA Version 15.1 statistical software. One hundred twenty-five patients (69 male and 56 female patients) were included. The average age at [[ventriculoperitoneal shunt placement]] was 2.3 ± 2.58 months. Sixty-one patients (48.8 percent) developed craniosynostosis at a median of 26 months after shunt placement. Of these, 28 patients fused one suture; the majority involved the sagittal suture (n = 25). Thirty-three patients fused multiple sutures; the most common were the coronal (n = 32) and the sagittal (n = 30) sutures. Multivariable logistic regression identified older age at shunt placement and more shunt revisions as independent predictors of craniosynostosis. Shunt valve type was not significant. Craniosynostosis developed in nearly half of infants who underwent ventriculoperitoneal shunt placement for hydrocephalus. The [[sagittal suture]] was most commonly involved. The effect of suture fusion on subsequent cranial growth, shunt failure, or the development of intracranial pressure is unclear ((Bryant JR, Mantilla-Rivas E, Keating RF, Rana MS, Manrique M, Oh AK, Magge SN, Murnick J, Oluigbo CO, Myseros JS, Rogers GF. Craniosynostosis Develops in Half of Infants Treated for Hydrocephalus with a Ventriculoperitoneal Shunt. Plast Reconstr Surg. 2021 Jun 1;147(6):1390-1399. doi: 10.1097/PRS.0000000000007988. PMID: 34019511.)). ---- Secondary craniosynostosis occurs in relation to a variety of causes: endocrine disorders hyperthyroidism hypophosphatemia vitamin D deficiency hypercalcemia hematologic disorders causing bone marrow hyperplasia sickle cell thalassemia inadequate brain growth microcephaly shunted hydrocephalus Shunt-induced [[craniosynostosis]] is a rare complication of [[ventricular shunt]]ing for [[hydrocephalus]] in [[pediatric]] patients. Although the exact [[pathophysiology]] of this form of secondary craniosynostosis is not well understood, the current understanding is that persistent [[drainage]] of the ventricular [[shunt]] causes decreased dural tension, resulting in decreased expansile force on the [[cranium]] and premature sutural [[fusion]]. Due to the low [[incidence]] of this [[complication]], there is no consensus on the ideal treatment for shunt-induced craniosynostosis. In recent years, distraction [[osteogenesis]] has been employed with greater frequency, as it is felt to counter the fundamental problem of decreased expansile force on the cranium. However, in a patient with a [[ventricular shunt]], placement of external hardware in close proximity to the shunt could cause significant morbidity due to the increased risk of shunt infection. Yan et al. presented the management of a patient with shunt-induced craniosynostosis who continued to be shunt-dependent. We chose to use fully buried springs to create an expansile force on the cranium as an alternative to external distractors so as to mitigate the risk of infection. We demonstrate that spring-assisted distraction osteogenesis can be an effective treatment modality for patients with shunt-induced craniosynostosis. This method should be considered in patients with contraindications to external distraction devices, such as ongoing shunt dependency ((Yan Y, Bacos JT, DiPatri AJ Jr, Gosain AK. Spring-Assisted Distraction Osteogenesis for the Treatment of Shunt-Induced Craniosynostosis [published online ahead of print, 2020 Aug 12]. Cleft Palate Craniofac J. 2020;1055665620947617. doi:10.1177/1055665620947617)).