Posterior Vault Distraction Osteogenesis for Craniocerebral Disproportion in a Pediatric Patient with Chronic Headaches: An Atypical Presentation and Evolving Role of Calvarial Volume Expansion

Overview of Craniocerebral Disproportion and Elevated Intracranial Pressure in Pediatric Patients

Craniocerebral disproportion (CCD) occurs when the intracranial space is inadequate to accommodate the growing brain. ¹ This is commonly associated with craniosynostosis, the premature fusion of 1 or more cranial sutures, which restricts skull growth and lead to a range of neurologic symptoms. ² The skull comprises multiple bones joined by sutures; the adaptability of these junctions is essential for accommodating brain growth and ensuring proper cranial development.

Children with chronically elevated intracranial pressure (ICP) may present with a range of symptoms, including headaches, nausea, vomiting, visual disturbances such as blurred or double vision, seizures and blindness. ¹ In infants, signs of raised ICP may include a bulging fontanelle or widened sutures.^3,4 If left untreated, chronically elevated ICP can lead to irreversible neurological injury, visual deficits, and developmental delays. ³ Although the relationship between craniosynostosis, CCD, and elevated ICP is well established, this case highlights an atypical presentation of CCD without overt craniosynostosis, resulting in an elevated ICP and associated symptoms.

Contextualization of Atypical Presentation

Our patient presented with chronic headaches and elevated ICP, initially thought to be due to Idiopathic Intracranial Hypertension (IIH) or pseudotumor cerebri. However, a thorough diagnostic workup by the multidisciplinary team revealed findings more consistent with structural craniocerebral disproportion than classic IIH. The neurosurgical team added that the presentation was not consistent with “pseudotumor in the classic sense” and that there was no evidence of cerebral venous sinus thrombosis or an empty sella sign on magnetic resonance imaging (MRI).^{5 -7}

Instead, imaging demonstrated findings consistent with CCD, including small ventricles, diffuse effacement of subarachnoid spaces, and a “copper beaten” appearance of the calvarium.^2,8 These features suggested constrained intracranial volume and provided a structural explanation for her symptoms, suggesting that elevated ICP in this context was driven by structural volume constraint rather than CSF dysregulation alone.^5,6,9 Additionally, while CCD is classically associated with syndromic or overt craniosynostosis, this patient had neither, making her case particularly uncharacteristic and her diagnosis more nuanced.

This case underscores the importance of integrating radiologic data with clinical judgment when evaluating atypical presentations of presumed IIH. It also highlights CCD as a potentially underrecognized cause of headache and elevated ICP in children with normal ophthalmologic findings.^10,11

Prior Literature on Calvarial Expansion for Non-synostotic Elevated ICP

Although PVDO is well established for syndromic craniosynostosis,^2,12,13 a small but growing body of literature supports the use of calvarial expansion for elevated ICP in patients without primary craniosynostosis. Ellis et al ¹⁴ described internal cranial expansion (ICE) in 10 consecutive patients with refractory IIH, reporting symptomatic improvement or resolution in 70% at a mean follow-up of 15.5 months. Ballestero et al ¹⁵ reported on cranial morcellation decompression for refractory pediatric IIH and identified only 7 prior pediatric cases in the literature treated with surgical skull expansion for this indication. More recently, Afshari et al ¹⁶ described cranial vault expansion as a viable and safe CSF diversion sparing alternative in pediatric IIH cases refractory to medical treatment, particularly in patients with extremely small ventricles where shunt placement is technically challenging. A 2024 systematic review by Friso et al ¹⁷ identified only 9 of 193 surgically treated pediatric IIH patients who underwent internal cranial expansion, compared to 115 who received CSF diversion, underscoring the rarity of this approach. The largest and most directly relevant series comes from the Children’s Hospital of Philadelphia, where Carlson et al ¹⁸ retrospectively reviewed patients who underwent cranial vault expansion from 2008 to 2023 specifically for craniocerebral disproportion without a diagnosis of primary craniosynostosis, including patients with refractory IIH and slit ventricle syndrome. Carlson and Taylor’s ¹² review of PVDO indications and outcomes further establishes the safety and volumetric efficacy of posterior distraction, with reported intracranial volume increases of 15% to 30%. Jagadeesan et al ¹⁹ highlighted the diagnostic overlap between IIH and undiagnosed craniosynostosis in a cohort of 19 normocephalic children, noting that subtle synostosis may be missed in patients presenting with IIH symptoms and a normal head shape. Collectively, these reports establish precedent for calvarial expansion in non-synostotic CCD and refractory IIH, though the evidence base remains limited to case reports and small retrospective series.

Distinguishing Features of the Present Case

Our patient’s presentation differs from prior reports in several respects. Unlike the Ellis et al and Afshari et al cohorts, which included patients with active papilledema and threatened vision as primary indications for surgery, our patient’s previously documented papilledema had resolved by the time of surgical evaluation, and vision was not threatened. This placed her outside the conventional indications for either CSF diversion or cranial expansion. The primary surgical indication was persistent, debilitating headaches with radiographic evidence of CCD, including small ventricles, effaced subarachnoid spaces, and a copper beaten calvarium, in the absence of identifiable craniosynostosis on CT with 3D reconstruction. Additionally, continuous ICP bolt monitoring showed values in a borderline rather than frankly elevated range (10-20 mmHg with brief nocturnal spikes), further complicating the decision to intervene surgically. The combination of these features, CCD without craniosynostosis, resolved papilledema, borderline ICP values, and a predominantly headache driven presentation, represents a clinical phenotype not well characterized in the existing literature. In contrast to the CHOP series, which included patients with slit ventricle syndrome and shunted hydrocephalus alongside IIH, our patient had no prior neurosurgical history and no shunt hardware, making this a de novo surgical decision for a structural problem identified through multidisciplinary diagnostic workup rather than through failure of prior neurosurgical interventions.

Significance of the Case

This report aims to document the diagnostic journey and successful surgical management of a pediatric patient with chronic headaches and elevated ICP due to CCD. It emphasizes the role of PVDO as a primary intervention in such an atypical scenario where the underlying cause is a structural constraint rather than abnormal CSF flow.

The use of PVDO in this context suggests its potential as a treatment option for craniocerebral disproportion in select patients, potentially extending its role beyond conventional indications such as synostosis and papilledema. PVDO’s potential role may include managing chronic, refractory headaches secondary to CCD when CSF diversion is not warranted and addressing anatomical volume mismatch in select patients. Furthermore, this case illustrates the diagnostic value of combining neuroimaging, ophthalmology, neurology, and surgical expertise within a shared interdisciplinary framework.

Initial Symptoms and Medical History

Our patient, a 7-year-old non-obese female, presented with chronic daily headaches. Over the preceding months, those headaches became more intense and frequent, often accompanied by vague but persistent sensations of eye pain and pressure. Her mother noted she appeared increasingly fatigued, partly attributed to her Diamox regimen.

She carried a diagnosis of IIH and had a known, stable pineal gland cyst noted on earlier MRIs. Her care team had been managing her conservatively with low-dose acetazolamide (125 mg twice daily) and serial high-volume lumbar punctures (LPs). While these LPs initially brought weeks of relief, their effect began wearing off more quickly, sometimes lasting only a few days.

Comprehensive Diagnostic Findings

CT Findings

October 15, 2024 (CT Head and Maxillofacial without IV contrast, CT 3D Reconstruction)

This imaging revealed small bilateral lateral ventricles and scalloping of the inner table of the skull due to cortical gyri impressions bilaterally, described as a “copper beaten appearance.” These findings are consistent with the long-standing pressure effect on the growing skull (Figure 1). ¹⁰

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Figure 1.

Skull X-ray (10/15/2024) demonstrating a “copper beaten” appearance, with scalloping of the inner calvarial table due to chronic impressions from underlying cortical gyri—suggestive of longstanding elevated intracranial pressure.

November 12, 2024 (Preoperative Planning CT)

This scan re-demonstrated stable small lateral ventricles and persistent scalloping of the inner bony table. There was a loss of extraparenchymal CSF spaces, including cortical sulci and subarachnoid spaces appeared effaced. The intracranial environment had a crowded appearance, further supporting the diagnosis of chronically elevated ICP due to anatomical constraint (Figure 2).

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Figure 2.

Axial CT scan (11/12/2024) showing small-caliber lateral ventricles and prominent scalloping of the inner skull table from chronic cortical gyri impressions.

Key Diagnostic Insights

Earlier MRI scans (2022-2023) revealed optic nerve sheath distention, mild globe flattening, and findings consistent with papilledema. However, by the time of formal ophthalmologic evaluation in October 2024, optic nerve heads appeared normal, suggesting that papilledema had resolved, likely in response to medical management with acetazolamide and serial lumbar punctures. Despite this resolution, the patient’s headaches persisted and worsened.^5,6 The apparent contradiction between earlier imaging suggestions and later clinical ophthalmological assessments highlights the challenge in distinguishing true papilledema or subtle anatomical variants, such as myelinated retinal nerve fiber layers, which can mimic optic disk swelling. ¹² The persistence of symptoms despite resolution of papilledema further supported a structural rather than purely pressure-mediated etiology.

Second, the consistent identification of small ventricles, effacement of subarachnoid spaces, and a “copper beaten” skull appearance on multiple CT and MRI scans strongly implicated CCD as the underlying cause of the patient’s elevated ICP symptoms. This structural abnormality, present across multiple scans, provided a clear anatomical explanation for the elevated ICP. In contrast, IIH typically presents with normal or even enlarged ventricles, and the skull usually lacks these chronic remodeling signs. ⁹ The child’s skull simply was not keeping up with her brain’s growth. That mechanical mismatch, rather than a CSF flow or absorption problem, was likely causing the elevated pressures (Table 1).

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Table 1.

Chronological Summary of Key Diagnostic Findings.

Date	Diagnostic test	Key findings
12/02/2022	MRI brain & orbits	1.2 cm pineal gland cyst; diminutive lateral ventricles; slight optic nerve head bulging, increased CSF in optic sheath (suggestive of IH)
01/25/2023	MRI brain & orbits, MR venogram	11 mm pineal cyst; mild bilateral optic disk elevation/enhancement, distended optic nerve sheaths, globe flattening (indicating papilledema); patent intracranial venous system
03/17/2023	MRI Brain	1.2 cm pineal cyst; slightly small lateral ventricles; suggested papilledema (concerning for IH)
09/04/2024	Lumbar puncture	Opening pressure: 29 cm H2O
10/14/2024	Lumbar puncture	Opening pressure: 29 cm H2O mmHg
10/15/2024	LP, CT head/maxillofacial	LP opening pressure: 30 mmHg; CT: Small lateral ventricles, “copper beaten” skull (consistent with IH); bilateral paranasal sinus mucosal disease
10/22/2024	Ophthalmological exam	Myelinated RNFL OU; optic nerves “pink, flat and healthy”; NO ONH edema; stable vision
11/12/2024	Preoperative planning CT	Stable small lateral ventricles and persistent “copper beaten” skull appearance

Multidisciplinary Assessment and Collaborative Decision-Making

The complex and atypical nature of the patient’s condition required input from multiple specialties, including Neurosurgery, Plastic Surgery, Neurology, and Ophthalmology.

Discussions were held with the family at the craniofacial multidisciplinary clinic, which served as a central forum for integrated care and shared decision-making. The initial working diagnosis favored pseudotumor cerebri, given the patient’s chronic headaches and elevated LP opening pressures. However, the imaging findings did not align with classic IIH, and the resolution of previously documented papilledema despite persistent symptoms raised further diagnostic questions.^5,6 As the evaluation progressed, the team leaned toward a more anatomically explanation: CCD without overt craniosynostosis.^2,9 This refinement of diagnosis highlights the value of multidisciplinary collaboration in complex cases where symptoms and finding do not fit neatly into traditional diagnostic patterns.

Rationale for Posterior Vault Distraction Osteogenesis (PVDO)

Despite the patient’s ICP continuous monitoring showing values generally within a “relatively normal range” (10-20 mmHg, with brief nighttime spikes to the low 30 seconds) and the resolution of previously noted papilledema on recent ophthalmological examinations, the decision was made to proceed with PVDO. The primary rationale was to directly address the restrictive intracranial environment. Meanwhile, she was becoming increasingly refractory to medical therapy and repeated lumbar punctures.

On the other hand, ventriculoperitoneal shunt (VPS) is typically reserved for IIH patients with medically refractory elevated ICP and threatened vision or severe papilledema.^5,13 More importantly, a shunt would not have addressed the insufficient cranial vault volume. The team emphasized that a shunt would remain an option if needed later, but PVDO offered the chance to avoid a lifelong shunt dependency.

This decision to perform PVDO, despite “normal” ICP monitoring and resolved papilledema, represents a significant deviation from typical IIH management guidelines. It highlights an emerging indication for PVDO: directly increasing intracranial volume to relieve pressure symptoms caused by anatomical disproportion, even when the classic signs of severe ICP are absent.

Pre-Operative Planning

To support precise surgical execution, the team obtained updated CT scans with 3D reconstruction for virtual planning. These helped guide osteotomy lines and distractor placement, following contemporary best practices for customized cranial vault expansion.^2,20 The presurgical plan includes ensuring the occipital craniotomy is at least 1.5 cm above the torcula.

On November 26, 2024, an ICP bolt was placed, allowing 24-hour monitoring without sedation. This avoided the potential dampening effect of sedatives on cerebrospinal pressure and gave the team a better look at her “real-time” ICPs. Pressures hovered in the 10 to 20 mmHg range, with brief spikes into the upper 20s/low 30s during sleep, findings consistent with borderline or intermittently elevated ICP.

Operative Technique (November 27, 2024)

Biparieto-occipital craniotomy for posterior vault distraction osteogenesis was performed jointly by the Neurosurgery and Craniofacial Plastic Surgery teams. Under general anesthesia, the patient was carefully positioned prone on a horseshoe headrest. Extra care was taken to avoid pressure on the eyes and bony prominences.

A bicoronal stealth incision was marked and infiltrated with 0.5% lidocaine with epinephrine to aid hemostasis and provide local analgesia. A 3D-printed cutting guide was utilized to mark craniotomies, ensuring precise bone cuts. Burr holes were created using acorn burs and further developed with a Kerrison rongeur. A B5 craniotome completed the craniotomies, with additional burr holes in the parietal bosses to ensure adequate dural mobility for bone flap manipulation.

Following the craniotomies, two 40 mm KLS Martin cranial distractors were applied. Proper engagement and functionality of the distractors were verified. The case was completed without complications (Figures 3 and 4).

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Figure 3.

Axial non-contrast CT brain image obtained postoperatively (01/05/2025), showing expected postoperative changes consistent with prior posterior vault distraction osteogenesis (PVDO). The lateral ventricles appear mildly expanded compared to prior imaging, with improved definition of the ventricular contours, suggesting increased intracranial volume.

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Figure 4.

Sagittal CT bone window and 3D-reconstructed cranial imaging (viewed from vertex) demonstrating interval changes consistent with posterior vault distraction osteogenesis (PVDO). The sagittal view highlights posterior calvarial advancement, while the 3D reconstruction reveals expanded occipital contour and increased intracranial volume from a superior perspective.

Re-Evaluating IIH Diagnosis in Atypical Pediatric Presentations

This case challenges the conventional understanding of Idiopathic Intracranial Hypertension (IIH) in pediatric patients. While the patient presented with classic IIH symptoms (chronic headaches, elevated LP pressures), the resolution of papilledema despite persistent symptoms, the absence of empty sella and venous sinus stenosis, and the consistent imaging findings of structural volume constraint led the multidisciplinary team to consider alternative diagnoses. The literature on atypical IIH presentations often relies on specific MRI features like empty sella or optic nerve sheath distension for diagnosis.^5,6

Instead, the consistent imaging findings of CCD, such as small ventricles, effacement of subarachnoid spaces, and a “copper beaten” skull, were identified as the primary drivers of elevated ICP. This raises the possibility that CCD, even in the absence of overt craniosynostosis, may represent a distinct and potentially underrecognized cause of elevated ICP. This case provides a plausible anatomical explanation for the elevated ICP, distinguishing it from purely idiopathic cases. It raises the possibility of a distinct subtype of elevated ICP that is anatomically driven by skull-brain mismatch rather than a CSF flow issue. While generalizable conclusions cannot be drawn from a single case, this observation suggests that diagnostic algorithms in pediatric headache clinics may benefit from more routine consideration of CCD beyond classic craniosynostosis.

Expanding Indications for Posterior Vault Distraction Osteogenesis

While PVDO is well established in managing syndromic craniosynostosis, this case suggests it may also have a role in select non-synostotic CCD patients with elevated ICP symptoms. Her successful outcome, with a 17.3% increase in estimated intracranial volume and sustained symptomatic resolution, demonstrates that PVDO can improve symptoms by directly addressing the mismatch between brain volume and calvarial capacity.^2,13,14,20

In the absence of true craniosynostosis or overt IIH, few surgical options are typically considered. CSF shunting, while effective in IIH with visual threat, carries long-term risks and was not justified in this scenario, given the absence of outflow tract abnormalities on scans and threatened vision on eye exams. PVDO provided a targeted, anatomic correction without exposing the patient to permanent shunt hardware.^5,13

In our patient, alternative management strategies were considered and found inadequate. Continued medical therapy with acetazolamide and serial lumbar punctures had been pursued for over 2 years with diminishing efficacy. CSF diversion via ventriculoperitoneal shunt was not favored given the absence of CSF flow abnormalities and the lack of threatened vision. Continued observation alone was felt to be inappropriate given the progressive and debilitating nature of her symptoms. In this context, posterior vault expansion offered a targeted anatomical correction. This case suggests that PVDO may be appropriate not only for cosmetic or syndromic cases, but also for carefully selected patients with subtle CCD and refractory symptoms, even when papilledema has resolved and classic craniosynostosis is absent.

Lessons Learned and Future Directions

This case emphasizes that elevated ICP in children is not always idiopathic, and that persistent symptoms despite resolution of papilledema should prompt consideration of structural anatomical causes such as CCD. It also suggests that structural correction via PVDO may meaningfully improve quality of life in carefully selected patients with nontraditional presentations, though further study is needed to define optimal patient selection criteria.

Future studies could explore how often CCD without overt synostosis contributes to atypical IIH presentations and evaluate PVDO as a primary intervention in these cases. Long-term data on neurocognitive and ophthalmologic outcomes would also strengthen the argument for earlier surgical consideration.

Limitations

Several limitations of this report should be acknowledged. First, as a single case report, the generalizability of our findings is inherently limited, and no causal conclusions can be drawn. Second, a validated pediatric headache outcome measure such as PedMIDAS was not used prospectively, and symptom improvement is based on subjective parental report. Third, intracranial volume was estimated using the ellipsoid approximation method rather than formal segmentation based volumetric analysis, which may introduce measurement imprecision. Fourth, postoperative ICP was not objectively documented, as the clinical team determined that invasive pressure monitoring was not warranted in an asymptomatic child. Fifth, the follow-up period of approximately 8 months, while encouraging, does not capture long-term recurrence risk, particularly during the adolescent growth spurt. Finally, no comparison to alternative management strategies (continued medical therapy, CSF diversion, or observation) is possible in the context of a single patient. Future prospective studies incorporating validated outcome measures, formal volumetric analysis, and longer follow-up are needed to further define the role of PVDO in non-synostotic CCD.