Complete Resolution of Papilledema in Syndromic Craniosynostosis with Posterior Cranial Vault Distraction.

We report a case of surgical management of Crouzon syndrome with multisuture craniosynostosis presenting with increased intracranial pressure (ICP) manifesting with chronic papilledema without ventriculomegaly. A 12-month-old boy had complete resolution of papilledema after posterior cranial vault distraction followed by staged fronto-orbital advancement. Expansion of the cranial vault with posterior distraction osteogenesis posed an elegant treatment, obviating ventriculoperitoneal shunt placement for cerebrospinal fluid (CSF) diversion. Strategies for the management of elevated ICP without ventriculomegaly in craniosynostosis include CSF shunting and cranial vault expansion. Posterior calvarial vault distraction associated with resolved papilledema has not been previously reported. Addressing the craniocephalic disproportion for this child with chronic papilledema, without ventriculomegaly, allowed the possibility of shunt freedom.

INTRODUCTION

Craniosynostosis, the premature fusion of one or more cranial sutures, affects approximately 1 in every 2000–2500 live births.[1] The relationship between increased craniosynostosis and intracranial pressure (ICP) has been well described.[2345678910] Intracranial hypertension (IH) is especially correlated with syndromic cases occurring in about 30%–50% of these patients.[68] The risk is lower in nonsyndromic patients, with 8%–20% experiencing increased ICP.[269] Detecting and treating elevated ICP in these patients is important due to the potential risk that prolonged elevated ICP poses for long-term cognitive deficits, neurologic damage, and vision loss.[6]

The problem of managing elevated ICP in pediatric patients is not straightforward. There is no universally agreed upon normal range of ICP values in children.[8] Furthermore, variable intracranial compliance in young patients complicates measurements.[58] Cerebrospinal fluid (CSF) shunting may be difficult to optimize in some cases, with shunt dependence adding complexity to long-term craniosynostosis management.[10] The physical presence of CSF shunt tubing may complicate plans for future staged craniofacial surgeries for cranial vault and facial bone reconstruction and expose patients to additional risks.

CASE REPORT

Our patient was born at 39 weeks through cesarean section. At birth, he was noted to have a syndromic appearance and was diagnosed with Crouzon syndrome. His 1st month was marked by recurrent ear infections and upper airway problems. At 5 months, he was found to have bilateral papilledema, which went untreated. Computed tomography (CT) of the head had shown no craniosynostosis. He had no medical interventions until 7 months later when he came to our center. At the time, physical examination was concerning for a bulging anterior fontanelle and bilateral papilledema [Figure 1a and b], representing elevated ICP. He met developmental milestones. CT scan at 12 months showed left coronal, left lambdoid, and partial right lambdoid craniosynostosis [Figure 2] without ventriculomegaly. Multidisciplinary input for his complex case was coordinated quickly. Patient was recommended for surgical intervention.

Figure 1

(a and b) Representative optic nerve photographs showing bilateral optic nerve edema. Both optic nerves are cupless, with blurred margin 30° and vasocongestion of disc vessels. (c and d) Postoperative fundus photographs demonstrating bilateral resolution of optic nerve edema, pink optic nerves with sharp margins, and return to normal cut-to-disc architecture in both eyes

Figure 2

(a and b) Preoperative three-dimensional reconstructions of computed tomography scan showing left coronal, left lambdoid, and partial right lambdoid craniosynostosis. Anterior view (left) and posterior view (right). (c and d) Preoperative magnetic resonance imaging brain, axial T2 sequences. Bilateral optic nerve sheath enlargement, optic papilla protrusion, and posterior globe flattening, suggestive of papilledema

At our institution, staged surgery is typically recommended for syndromic craniosynostosis, first with calvarial vault expansion with posterior vault distraction, followed by fronto-orbital advancement after 3 months. Consideration was given to direct CSF diversion in the form of ventriculoperitoneal shunting to reduce ICP. Given his intact visual function and chronic 7-month history of papilledema, other alternatives were considered, including cranial vault expansion. The decision was made to pursue the latter, with close follow-up, for the advantages of shunt freedom.

The patient underwent a preoperative magnetic resonance (MR) venogram of the brain to rule out intracranial-extracranial collateral vessels that may be in the surgical field of the planned posterior approach. There were no collaterals and no venous sinus thrombosis. MR imaging brain also showed findings consistent with the physical examination finding of papilledema, with optic nerve sheath enlargement, protrusion of optic papillae, and posterior globe flattening [Figure 2]. He underwent surgery, with airway evaluation through laryngoscopy and bronchoscopy at intubation, as per protocol with syndromic craniofacial patients; these were normal. A craniotomy was performed, releasing the posterior vault bone flap, and posterior distractor hardware was placed. Patient had initiation of distraction on postoperative day 1 and subsequent serial distraction to a bony gap of 2 cm [Figure 3].

Figure 3

(a) Lateral skull X-ray after posterior vault distraction, removal of hardware, and fronto-orbital advancement. (b and c) Lateral skull X-rays showing posterior vault distraction distance of 2 cm

After surgery, his papilledema improved and resolved over time in 3 months, before his next surgery. He remained developmentally normal, and his postoperative course was uncomplicated. As planned, the patient had staged surgery, with the removal of posterior distraction hardware and fronto-orbital advancement 3 months later [Figure 3]. After his second surgery, the patient remained developmentally normal, with continued complete resolution of papilledema [Figure 1c and d]. At 6-months' follow-up, he remained developmentally normal with no signs of increased ICP.

DISCUSSION

Multiple factors contribute to the pathophysiology of elevated ICP in syndromic craniosynostosis. One cause is craniocerebral disproportion due to prematurely fused sutures. While the number of fused sutures shows a correlation to increase in ICP, the relationship between reduced intracranial volume and increased ICP is not linear.[3] Other mechanisms responsible for elevated ICP include venous congestion, hydrocephalus, and upper airway obstruction. Venous anomalies are frequently noted in syndromic craniosynostosis. These irregularities are thought to result in venous hypertension, which raises the pressure gradient for CSF absorption.[7] Irregular dilatations of the subarachnoid spaces are commonly seen in single-suture craniosynostosis.[9] How this may impact CSF flow is unclear. Some have proposed that changes in the bone along the suture line may alter the absorptive abilities of the arachnoid granulations.[4] Others have proposed that excessively high brain pulsation alteration of CSF absorption may be responsible.[11] In addition, upper airway obstruction has been shown to correlate with hypercapnia and increased ICP.[1213]

Ventriculoperitoneal shunts have long been considered the gold standard in addressing active hydrocephalus in this subset of children. One study estimated that 12% of children required ventriculoperitoneal shunts after surgical cranial vault expansion for the management of hydrocephalus, with or without papilledema.[12] While this case did not have hydrocephalus or ventriculomegaly, the patient did have elevated ICP, and the mainstay of neurosurgical treatment for elevated ICP with papilledema, with or without ventriculomegaly, is CSF diversion. However, concerns related to the use of shunts exist. Apart from common shunt-related morbidities, there are other concerns in children with complex craniosynostosis. Venous hypertension is difficult to directly address, leading to the possibility of persistent IH, even in the presence of a shunt. In addition, drained CSF spaces will soon fill with growing brain; however, the reconstructed skull may be without a primary growing stimulus if there is overdrainage of CSF. This phenomenon has been posited to favor the tendency of the cranial vault sutures to close prematurely.[1415] Finally, the presence of shunt hardware may be in the surgical field in staged craniofacial procedures, exposing the hardware to the risk of infection and dislodgment.

Strategies for management of hydrocephalus or elevated ICP in craniosynostosis include CSF shunt, endoscopic third ventriculostomy, and cranial vault expansion.[1617] To our knowledge, posterior calvarial vault distraction associated with resolved papilledema has not been reported. Addressing the craniocephalic disproportion for a child with chronic papilledema allowed for the possibility of shunt freedom in this case. Given signs of elevated ICP secondary to syndromic craniosynostosis without ventriculomegaly, our patient was planned for staged surgery without initial shunting. The first stage included posterior cranial vault distraction to enlarge intracranial volume and help with soft tissue expansion while laying down new cranial bone. The second stage, after bone consolidation, included removal of posterior hardware and frontal orbital advancement. This treatment plan made it possible to address the craniocephalic disproportion contributing to increased ICP and avoid ventriculoperitoneal shunt placement. This is desirable, given the high rate of shunt complications, including infections, malfunctions, and the need for subsequent revisions and shunt surgeries. As the papilledema resolved before planned frontal orbital advancement, it was fortuitous that we had not committed to placing VP shunt hardware for CSF diversion, as there would be a real risk of exposing the shunt components during the second staged procedure, further exposing the shunt circuit to risks of infection and malfunction.

A gold standard treatment for children with syndromic craniosynostosis has not yet been established. There is ongoing debate due to the multifaceted etiology of CSF dynamic disorders. The role of posterior fossa distraction, as seen in our patient, was aimed to address the main postulated causes of increased ICP by expanding intracranial volume and correcting craniocephalic disproportion; any venous outflow congestion would likely remain. Close neurologic follow-up and ophthalmologic evaluation were crucial.

CONCLUSIONS

In this 12-month-old patient with Crouzon syndrome and multisutural synostosis, expansion of the cranial vault with posterior distraction osteogenesis posed an elegant treatment for high ICP and papilledema, obviating ventriculoperitoneal shunt placement. This novel case suggests a possible algorithm for the management of multisuture synostosis and provides options for CSF shunt freedom in selected cases.

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Conflicts of interest

There are no conflicts of interest.