Craniosynostosis and hydrocephalus: relevance and treatment modalities

Maximizing the functional benefits of posterior calvarial vault distraction in syndromic craniosynostoses: a nuanced approach to volume, vein, vector, and the vexed challenge of functional outcome in craniosynostoses

PURPOSE

To evaluate indications, techniques, nuances, and outcomes of posterior cranial vault distraction (PCVD) in children with craniosynostoses.

METHODS

We performed clinical assessments, multidimensional CT, MRI brain rapid protocol, ophthalmological evaluation, sleep study, and nasal endoscopy (if indicated). Detailed data was collected in Excel. Customized craniotomy (supratorcular or subtorcular), distraction vectors, strategic barrel staving on stenosed bones (other than lambdoid), and ~ 2 cm relief craniectomy for venous decompression were employed. Additional procedures were performed for the frontal and midface aspects during distractor removal based on functional needs.

RESULTS

Thirty-seven patients (ages 4-204 months, mean 32.94 months) underwent PCVD. Supratorcular PCVD in 8, subtorcular in 29. The distraction vector was posterior-horizontal in 28 cases and posterior-inferior in 9. Strategic barrel staving was used in 8 cases, and venous decompression in 24. Initial assessments showed satisfactory clinical and radiological outcomes. Long-term follow-up indicated seven of 11 patients with hydrocephalus required a ventriculoperitoneal shunt, and two needed additional PCVD procedures due to symptom recurrence. Average intracranial volume increased by 186 ± 42.67 cm3 (18 patients), and the average distraction achieved was 21 ± 2.64 mm (37 patients). Additional procedures at the time of distractor removal included fronto-facial or monobloc advancement (n = 3), isolated fronto-orbital advancement and remodeling (n = 13), and midface distraction for airway issues (monobloc advancement, n = 3; isolated midface, n = 9). Nine patients underwent all three procedures in sequence.

CONCLUSION

PCVD is an accepted surgical strategy for craniosynostosis with posterior calvarial involvement. Our technical modifications aim to enhance functional and aesthetic outcomes without increasing morbidity.

Free-floating bone flap posterior cranial vault release in syndromic craniosynostosis

The aim of this study was to investigate the efficacy of non-detachable free-floating bone flap posterior cranial vault release (FFBF-PCVR) in syndromic craniosynostosis. A retrospective review was completed of subjects who underwent FFBF-PCVR at 4 time-points: within 3 months preoperatively, 7 days postoperatively, 3 months postoperatively and at the last follow-up postoperatively. Volumetric and craniometric data, the ratio of ventricular diameter, and the cerebellar tonsillar descent were measured after FFBF-PCVR by using computed tomographic and magnetic resonance imaging. A total of 19 patients underwent FFBF-PCVR. The mean age was 11.7 months (range 4-36 months). The mid cranial height, posterior cranial height, and anterior posterior diameter length significantly increased from preoperative to postoperative 7 days, from postoperative 7 days to postoperative3 months, and from postoperative 3 months to the last follow-up. There was a significant increase in pre- to 7 days postoperative intracranial volume (1195.21 ± 246.56 cm³, p < 0.001; respectively), 3 months postoperative intracranial volume (1228.03 ± 249.61 cm³, p < 0.001; respectively), and intracranial volume at last follow-up (1390.25 ± 219.99 cm³, p < 0.001; respectively). There was a significant increase in 7 days' postoperative to 3 months' postoperative intracranial volume (p < 0.001; respectively), and intracranial volume at last follow-up (p < 0.001; respectively). There was a significant increase in 3 months postoperative to intracranial volume at last follow-up (p < 0.001). The mean intracranial volume increased by an average of 36.6 percent (range, 18.1 to 79.2 percent) at last follow-up. The degree of hydrocephalus in the preoperative child was (45.77% ± 9.17%), and at the last follow-up after surgery, the degree of hydrocephalus was (35.02 ± 9.50%), p < 0.01). Preoperatively, 14 patients (73.7 percent) had radiographic evidence of Chiari malformation type I. The cerebellar tonsillar descent, measured using pre- and postoperative MRI, decreased in all patients after FFBF-PCVR (preoperative: 7.5 ± 1.4 mm, postoperative: 5.3 ± 1.7 mm; p = 0.001). FFBF-PCVR can efficiently expand the posterior cranial vault with only one surgical procedure. Moreover, it helps to relieve hydrocephalus and cerebellar tonsillar herniation.

Changes in Ventricular Volume After Posterior Vault Distraction Osteogenesis in Patients With Syndromic and Nonsyndromic Craniosynostosis

OBJECTIVE

Little is known about the response of the ventricular system to cranial vault surgery in patients with craniosynostosis. This study aims to evaluate the changes in the cerebral ventricular system in response to posterior vault distraction osteogenesis (PVDO) in patients with syndromic and nonsyndromic craniosynostosis.

METHODS

A single-institution retrospective review of all patients with craniosynostosis undergoing PVDO from 2000 to 2022 was completed. Patients were included for analysis if they had pre and postoperative cranial computed tomography scans. Ventricular volume (VV) and intracranial volume (ICV) were calculated using segmentation software.

RESULTS

Both patients with syndromic synostosis and nonsyndromic synostosis (NSS) experienced a significant increase in ICV after PVDO, but only patients with NSS experienced a significant VV change ( P = 0.004). After normalization by ICV, total, lateral, and third VV changes retained significance with percentage increases of 114%, 117%, and 89%, respectively ( P < 0.05 for all).

CONCLUSION

The differing results between cohorts reinforce the concept that the intracranial milieu is different between patients with syndromic synostosis and NSS. The results of the NSS cohort suggest that these patients may exist in a compensated state in which a reduction in cerebral blood flow and VV allows for the maintenance of parenchymal health to prevent the development of intracranial hypertension. Further studies may explore VV as a surrogate marker of ICP elevation, and the utility of cranial vault remodeling on nonsynostotic pathologies with cephalocranial disproportion.

Incidence of Ventriculomegaly in Patients With Craniosynostosis

Hydrocephalus is variously associated with syndromic craniosynostosis (CS), while it is randomly encountered in nonsyndromic CS. But actually, the ventriculomegaly in CS is less described. In this study, the authors aim to establish whether ventriculomegaly is common in patients with CS, in both syndromic and nonsyndromic. Retrospective measurements of Evans index (EI) were taken from thin-section computed tomography scans of 169 preoperative CS patients to assess cerebral ventricular volume. EI >0.3 indicates ventricular enlargement. A total of 169 CS patients who underwent computed tomography scan from February 2018 to December 2021 were retrospectively evaluated, including 114 males and 55 females. The average age at diagnosis was 16 months (range: 1-103 mo). Among them, 37 with syndromic CS, including 17 ventricular megaly patients, had an EI >0.3 (46.0%), and 4 of them had intracranial hypertension and needed ventriculoperitoneal shunt treatment before cranial vault remolding. One hundred and thirty-two had nonsyndromic CS (100 single-suture CS, 32 multisuture CS), and 26 of them had an EI of 0.3 or greater (19.7%). Ventrocular megaly is common among patients with CS. Early craniotomy may stabilize ventricular dilation.

Are Patients with Syndromic Craniosynostosis at Greater Risk for Epilepsy than Patients with Nonsyndromic Craniosynostosis?

OBJECTIVE

The aim of this study was to determine whether patients with syndromic craniosynostosis (SCS) are at increased risk for epilepsy relative to patients with nonsyndromic craniosynostosis (NSCS).

METHODS

A retrospective cohort study was completed using the Kids' Inpatient Database (KID). All patients diagnosed with craniosynostosis (CS) were included. The primary predictor variable was study grouping (SCS vs. NSCS). The primary outcome variable was a diagnosis of epilepsy. Descriptive statistics, univariate analyses and multivariate logistic regression were performed to identify independent risk factors for epilepsy.

RESULTS

The final study sample included a total of 10,089 patients (mean age, 1.78 years ± 3.70; 37.7% female). 9278 patients (92.0%) had NSCS, and the remaining 811 patients (8.0%) had SCS. A total of 577 patients (5.7%) had epilepsy. Not controlling for other variables, patients with SCS were at increased risk for epilepsy relative to patients with NSCS (OR 2.1, P < 0.001). After controlling for all significant variables, patients with SCS were no longer at increased risk for epilepsy relative to patients with NSCS (OR 0.73, P = 0.063). Hydrocephalus, Chiari malformation (CM), obstructive sleep apnea (OSA), atrial septal defect (ASD), gastro-esophageal reflux disease (GERD) were all independent risk factors (P < 0.05) for epilepsy.

CONCLUSIONS

Syndromic craniosynostosis (SCS) in itself is not a risk factor for epilepsy relative to NSCS. The greater prevalence of hydrocephalus, CM, OSA, ASD, and GERD, all of which were risk factors for epilepsy, in patients with SCS relative to patients with NSCS likely explains the greater prevalence of epilepsy in SCS relative to NSCS.

Technical evolution of pediatric neurosurgery: craniosynostosis from 1972 to 2023 and beyond

Very few clinical entities have undergone so many different treatment approaches over such a short period of time as craniosynostosis. Surgical treatments for this condition have ranged from simple linear craniectomies, accounting for the specific role of cranial sutures in assuring the normal growth of the skull, to more complex cranial vault reconstructions, based on the perceived role of the skull base in affecting the growth of the skull. While a great deal of evolution has occurred, there remains controversy regarding the ideal treatment including the best surgical technique, the optimal age for surgery, and the long-term morphological and neurodevelopmental outcomes. The evolution of the surgical management of craniosynostosis in the last 50 years has been affected by several factors. This includes the awareness of needing to operate on affected children during infancy to achieve the best results, the use of multistage operations, the availability of more sophisticated surgical tools, and improved perioperative care. In some forms of craniosynostosis, the operations can be carried out at a very young age with low morbidity, and with the postoperative use of a molding helmet, springs, or distractors, these operations prove to be as effective as traditional larger cranial reconstructions performed in older children. As a consequence, complex surgical operations have become progressively less utilized. A second relevant advance was the more recent advent of a molecular diagnosis, which allowed us to understand the pathogenesis of some associated malformations and neurodevelopmental issues that were observed in some children despite appropriate surgical treatment. Future research should focus on improving the analysis of longer-term outcomes and understanding the natural history of craniofacial conditions, including what issues persist despite optimal surgical correction. Progress in molecular investigations concerning the normal and pathological development of cranial sutures could be a further significant step in the management of craniosynostosis, possibly favoring a "medical" treatment in the near future. Artificial intelligence will likely have a role in establishing the diagnosis with less reliance on radiographic studies and in assisting with surgical planning. Overall, much progress has been made, but there remains much to do.

Imaging in craniofacial disorders with special emphasis on gradient echo Black-Bone and Zero Time Echo MRI sequences

Context:

The well-known effects of ionizing radiation on brain cells have been a major driving force toward the use of non-ionizing methods of imaging in both elective and emergency settings. Pediatric neurosurgery has certainly leveraged on this shift in clinical practice, however patients with craniofacial disorders could not fully benefit from the adoption of magnetic resonance imaging (MRI) because computed tomography (CT) scans still retain superior imaging power on bone tissue.

Aims:

To explore the knowledge available on the use of MRI as surrogate for CT scan in the assessment of craniosynostosis.

Settings and Design:

A scoping review was designed to identify landmark studies and ongoing clinical trials exploring the accuracy of MRI-based bone imaging in the preoperative planning of pediatric patients with craniosynostosis.

Materials and Methods:

A total of 492 records were screened from Pubmed, Ovid Medline, Scopus, and Cochrane Library databases; while 55 records were retrieved from ClinicalTrials.gov register. Only clinical studies revolving around the use of Gradient Echo Black-Bone (BB) and Zero Time Echo (ZTE) MRI sequences for the preoperative planning of pediatric craniosynostosis were retained for inclusion.

Results and Conclusions:

This review identified only five clinical studies reporting a high accuracy of MRI-based 3D bone reconstruction in 47 pediatric candidates to surgical correction of craniosynostosis. Although promising, limited evidence (Level IV) exist that BB and ZTE MRI could help in the surgical planning for craniosynostosis management. The results of two ongoing randomized clinical trials, which are actively enrolling patients, will hopefully help answering this research question.

Management of Chiari 1 malformation and hydrocephalus in syndromic craniosynostosis: A review

Chiari 1 malformation and hydrocephalus are frequent findings in multi-suture and syndromic craniosynostosis patients. In this article, we review the pathogenesis, clinical significance, and management options for these conditions with comments from our own experience. The role of premature fusion of skull base sutures leading to a crowded posterior fossa and venous outflow obstruction resulting in impaired cerebrospinal fluid (CSF) absorption is highlighted. Management options are unique in this group and we advocate early (prior to 6 months of age) posterior vault expansion by distraction osteogenesis (DO) in the management of Chiari 1 malformation. Foramen magnum decompression is recommended for a select few either as part of posterior vault expansion or at a later date. Treatment of hydrocephalus, utilizing a ventriculoperitoneal (VP) shunt with preferably a programmable high-pressure valve and anti-siphon device, is required in a small percentage of cases despite successful posterior vault expansion. Patients need to be carefully selected and managed as hydrocephalus often serves as an important cranial vault growth stimulus. Further, they require careful monitoring and thought to ensure the management of these conditions and the timing of any intervention provides the optimal long-term outcome for the patient.

Management of ventriculomegaly in pediatric patients with syndromic craniosynostosis: a single center experience

INTRODUCTION

Management of ventriculomegaly in pediatric patients with syndromic craniosynostosis (SC) requires understanding the underlying mechanisms that cause increased intracranial pressure (ICP) and the role of cerebrospinal fluid (CSF) in cranial vault expansion in order to select the best treatment option for each individual patient.

METHODS

A total of 33 pediatric patients with SC requiring craniofacial surgery were retrospectively evaluated. Cases of nonsyndromic craniosynostosis and shunt-induced craniosynostosis were excluded. Six syndrome-based categories were distinguished: Crouzon syndrome, Pfeiffer syndrome, Apert syndrome, cloverleaf skull syndrome, and others (Muenke syndrome, Sensenbrenner syndrome, unclassified). All of the patients were treated surgically for their cranial deformity between 2010 and 2016. The presence of ventriculomegaly and ventriculoperitoneal (VP) shunt requirement with its impact in cranial vault expansion were analyzed. Clinical and neuroimaging studies covering the time from presentation through the follow-up period were revised. The mean postoperative follow-up was 6 years and 3 months. A systematic review of the literature was conducted through a PubMed search.

RESULTS

Of the total of 33 patients with SC, 18 (54.5%) developed ventriculomegaly and 13 (39.4%) required ventriculoperitoneal (VP) shunt placement. Six patients (18.2%) required shunt placement previous to craniofacial surgery. Seven patients (21.2%) required a shunt after craniofacial surgery. Seven fixed pressure ventriculoperitoneal shunts and six programmable valves were placed as first choice. All patients improved their clinical symptoms after shunt placement. Aesthetic results seemed to be better in patients with programmable shunts.

CONCLUSIONS

Unless clear criteria for overt hydrocephalus are present, it is recommended to perform craniofacial surgery as a first step in the management of patients with SC in order to preserve the expansive effect of CSF for cranial vault expansion. In our experience, the use of externally programmable valves allows for the treatment of hydrocephalus while maintaining the expansive effect of CSF for the remodeling of the cranial vault. Prospective evaluations are needed to determine causality.

Posterior vault "free-floating" bone flap: indications, technique, advantages, and drawbacks

BACKGROUND

The enlargement of the posterior cranial fossa volume is considered one of the main steps of the surgical management of children with multiple sutures craniosynostosis. Different management options have been proposed including fixed expansive craniotomy, free bone flap craniotomy, and distraction osteogenesis.

OBJECTIVES

To review indications to "free bone flap" craniotomy for the posterior fossa expansion, detailing advantages, disadvantages, and complications related to the technique.

RESULTS AND CONCLUSIONS

A review of the literature shows that "free bone flap" posterior expansion cranioplasty still has a role, particularly in infants with thin and "honeycomb" structure of the bone, allowing to gain adequate intracranial volume increases and to postpone to a more adequate time surgery aimed at anterior cranial fossa expansion.