Occipital expansion without osteotomies in Apert syndrome

Apert syndrome: Cranial procedures and brain malformations in a series of patients

Background:

Apert syndrome is one of the most severe craniofacial disorders. This study aims to describe the craniofacial surgeries and central nervous system malformations of a cohort of children with Apert syndrome treated in the past 20 years and to compare these data with previously published data.

Methods:

Retrospective analysis of a series of patients with Apert syndrome treated between 1999 and 2019 in our hospital. Information was analyzed regarding craniofacial procedures, hydrocephalus and presence of shunts, Chiari malformation Type 1, and other brain malformations such as corpus callosum and septum pellucidum anomalies.

Results:

Thirty-seven patients were studied. Ventriculoperitoneal shunt prevalence was 24.3%, and 8.1% of patients required decompressive surgery for Chiari malformation. All of them needed at least one cranial vault remodeling procedure. The median age for this procedure was 8 months. In 69.7% of patients, the first cranial vault intervention was performed in the fronto-orbital region. In 36.4% of patients, a midface advancement had been performed at the time of this review, although this proportion was very dependent on the follow-up period and the age of the patients. The median age for the midface advancement procedure was 5.25 years. Anomalies of the corpus callosum and the septum pellucidum were reported in 43.2% and 59.5% of patients, respectively.

Conclusion:

Apert syndrome is a type of syndromic craniosynostosis, and patients usually require one or more cranial and facial surgeries. In comparison with other syndromic craniosynostosis types, Apert syndrome less frequently requires a VP shunt or treatment for a Chiari malformation.

A population-specific material model for sagittal craniosynostosis to predict surgical shape outcomes

Sagittal craniosynostosis consists of premature fusion (ossification) of the sagittal suture during infancy, resulting in head deformity and brain growth restriction. Spring-assisted cranioplasty (SAC) entails skull incisions to free the fused suture and insertion of two springs (metallic distractors) to promote cranial reshaping. Although safe and effective, SAC outcomes remain uncertain. We aimed hereby to obtain and validate a skull material model for SAC outcome prediction. Computed tomography data relative to 18 patients were processed to simulate surgical cuts and spring location. A rescaling model for age matching was created using retrospective data and validated. Design of experiments was used to assess the effect of different material property parameters on the model output. Subsequent material optimization-using retrospective clinical spring measurements-was performed for nine patients. A population-derived material model was obtained and applied to the whole population. Results showed that bone Young's modulus and relaxation modulus had the largest effect on the model predictions: the use of the population-derived material model had a negligible effect on improving the prediction of on-table opening while significantly improved the prediction of spring kinematics at follow-up. The model was validated using on-table 3D scans for nine patients: the predicted head shape approximated within 2 mm the 3D scan model in 80% of the surface points, in 8 out of 9 patients. The accuracy and reliability of the developed computational model of SAC were increased using population data: this tool is now ready for prospective clinical application.

Results and limits of posterior cranial vault expansion by osteotomy and internal distractors

Background:

Expanding the posterior cranial vault has become a common procedure in the treatment of complex craniosynostosis. Several techniques are available to remodel the posterior vault. Aim of this study was to analyze the posterior vault distraction osteogenesis.

Methods:

Between 2011 and 2014, 21 children (12 boys) were operated on for a posterior distraction of the cranial vault. The mean age was 8.6 months (minimum, 3 months; maximum, 15 years). Thirteen patients presented a craniofacial syndrome. Five had already been operated on (two anterior cranial surgery, two suboccipital decompression, and one craniotomy for sagittal synostosis). Raised intracranial pressure (ICP) was present in 6 patients. Seven patients had symptomatic cerebellar tonsils herniation (TH).

Results:

In 17 children, 2 lateral distractors were placed, in 3 a 3^rd medial distractor was placed, and in 1 child 4 distractors were implanted. Volumetric analysis based on computed tomography showed a mean increase of volume of 13.9% 117 days later. After the distraction, symptoms related to raised ICP or TH were improved in all patients, however, radiologically TH was improved at the last follow-up in 54% of the cases.

Conclusion:

Posterior cranial vault distraction is an efficacious technique to enlarge the posterior skull vault and treat increased ICP. Moreover, it appears to be efficacious in treating TH-related symptoms.

Apert syndrome: Surgical outcomes and perspectives

PURPOSE

Apert syndrome is a rare congenital malformation with severe craniofacial anomalies. The aim of this study was to review the outcomes of craniofacial and neurosurgical interventions in Apert syndrome patients treated at a single institution.

MATERIALS AND METHODS

A retrospective review of all patient records with a diagnosis of Apert syndrome assessed and managed in the Australian Craniofacial Unit (ACFU) from 1985 to 2013 was conducted.

RESULTS

A total of 94 patients were identified, and 130 transcranial procedures were performed. Of the patients, 83 underwent a fronto-orbital advancement (FOA) as their primary procedure, and 18 patients also underwent a posterior vault procedure. Twenty patients underwent a fronto-facial monobloc advancement. Overall, 70% of patients underwent at least 2 transcranial procedures. Shunts were inserted in 2 patients preoperatively and in 5 patients postoperatively for cerebrospinal fluid (CSF) leaks or acute hydrocephalus. Re-do FOAs were performed in 8 patients. Patients who underwent an FOA at the age of more than 18 months had no recurrence of raised intracranial pressure (ICP). Of 18 patients who also underwent a posterior vault procedure, 1 patient had recurrence of raised ICP. Midfacial surgery was performed early if there was evidence of obstructive sleep apnoea (OSA), but delayed midfacial surgery was preferred. Complications were reported in 18% of procedures. The most common complications were CSF leaks and acute hydrocephalus.

CONCLUSION

Shunting is rarely required in Apert syndrome patients, confirming a predominantly nonprogressive ventriculomegaly. FOA appears to be a more stable procedure when performed at an age of more than 18 months. Undergoing a posterior vault procedure may reduce the risk of recurrent raised ICP and lead to fewer transcranial procedures needed in childhood. Midfacial surgery should be delayed until adolescence where there is no evidence of OSA, psychological disturbance, or complications of exorbitism. Complications are rare when these patients are treated by an experienced craniofacial team.

Spring-assisted cranial vault expansion in the setting of multisutural craniosynostosis and anomalous venous drainage: case report

Patients with multisutural craniosynostosis can develop anomalous venous connections between the intracranial sinuses and cutaneous venous system through enlarged emissary veins. Cranial vault remodeling in this subset of patients carries the risk of massive intraoperative blood loss and/or occlusion of collateral draining veins leading to intracranial venous hypertension and raised intracranial pressure, increasing the morbidity of cranial expansion. The authors report the use of spring-mediated expansion as a technique for cranial reconstruction in which the collateral intracranial venous drainage system can be preserved. A patient with bilateral lambdoid, sagittal, and unicoronal synostosis presented for cranial reconstruction. A tracheostomy and ventriculoperitoneal shunt were placed prior to intervention. At the time of reconstruction, a Luckenschadel skull abnormality and Chiari malformation Type I were present. A preoperative CT venogram demonstrated large collateral superficial occipital veins, small bilateral internal jugular veins, and hypoplastic jugular foramina. Collateral flow from the transverse and sigmoid sinuses through large occipital emissary veins was seen. Spring-mediated cranial vault expansion was performed with care to preserve the large collateral veins at the occipital midline. Four springs were placed at each lambdoid and the posterior and anterior sagittal sutures following 1-cm strip suturectomies. Removal of the springs was performed 2 months postoperatively. Cranial vault expansion was performed without disturbing the aberrant intracranial/extracranial venous collateral system. Estimated blood loss was 150 ml. A CT scan obtained 3 months postoperatively showed resolution of the Luckenschadel deformity and a 40% volumetric increase in the skull compared with the preoperative CT. Patients with anomalous venous drainage patterns and multisutural synostosis can undergo spring-mediated cranial vault expansion while preserving the major emissary veins draining the intracranial sinuses. Risks of blood loss, intracranial venous hypertension, and increased intracranial pressure may be decreased compared with traditional techniques of repair.

Results of posterior cranial vault remodeling for plagiocephaly and brachycephaly by the meander technique

OBJECTIVE

Several techniques to remodel the posterior calvarium in order to increase intracranial volume (ICV) and to improve cosmetic appearance are reported. This study presents the results of meander technique in patients with brachycephaly and posterior plagiocephaly.

METHODS

During December 2011 and July 2013, a total of 12 children (median age: 15 months) underwent posterior cranial vault remodeling by the meander technique (brachycephaly, n = 6; posterior plagiocephaly, n = 6). The available pre- and postoperative MRIs were assessed with regard to ICV, cranial index (CI) and asymmetry index (AI) as well as the position of the cerebellar tonsils.

RESULTS

No intra- or postoperative complications were observed. Blood transfusions were necessary in nine of 12 patients. A significant increase of the ICV from 1,178.4 ± 134.5 to 1,293.0 ± 137.5 cm(3) (p < 0.05) is demonstrated. In the patients with brachycephaly the CI was significantly improved from 0.97 ± 0.12 to 0.89 ± 0.12 postoperatively (p < 0.05). The AI in patients with posterior plagiocephaly was significantly ameliorated from 0.83 ± 0.04 to 0.92 ± 0.02 postoperatively (p < 0.05). There was a significant effect on cerebellar tonsil position in relation to foramen magnum level for patients with brachycephaly (right tonsil: 11.9 ± 9.2 to 7.0 ± 9.1 mm, p < 0.05; left: 10.8 ± 9.5 to 9.7 ± 10.6 mm; p < 0.05) as well as in posterior plagiocephaly for the ipsilateral tonsil (3.2 ± 3.5 to 1.6 ± 3.5 mm; p < 0.01).

CONCLUSION

The presented surgical technique is considered to be safe. The technique is capable to significantly increase ICV and improve cosmetic appearance of the remodeled calvarium. Further evidence that posterior cranial vault remodeling influences the position of the cerebellar tonsils is added by the results of the study.

Syndromic craniosynostosis

Although most cases of craniosynostosis are nonsyndromic, craniosynostosis is known to occur in conjunction with other anomalies in well-defined patterns that make up clinically recognized syndromes. Patients with syndromic craniosynostoses are much more complicated to care for, requiring a multidisciplinary approach to address all of their needs effectively. This review describes the most common craniosynostosis syndromes, their characteristic features and syndrome-specific functional issues, and new modalities utilized in their management. General principles including skull development, the risk of developing increased intracranial pressure in craniosynostosis syndromes, and techniques to measure intracranial pressure are discussed. Evolving techniques of the established operative management of craniosynostosis are discussed together with more recent techniques including spring cranioplasty and posterior cranial vault distraction osteogenesis.

Spring-assisted posterior vault expansion in multisuture craniosynostosis

PURPOSE

Patients with Apert and Crouzon syndromes and craniofrontonasal dysplasia need a vault expansion within the first year of life to treat or prevent the development of raised intracranial pressure. Many craniofacial units perform a conventional posterior vault expansion as initial surgery; an alternative to this technique is the spring-assisted posterior vault expansion. The purpose of this study was to demonstrate the efficacy of spring-assisted posterior vault expansion and to compare this technique with the conventional method.

METHODS

A retrospective study was conducted among all consecutive patients who received a posterior vault expansion between 2006 and 2011. Patients treated with springs were compared with patients treated with the conventional technique for blood loss, duration of surgery, postoperative hospital admittance, increase in skull circumference and anterior-posterior length, and complications.

RESULTS

Of the 31 included patients, 15 were treated with springs, and 16, with the conventional technique. Patients treated with springs had a significantly larger increase in skull circumference and anterior-posterior length, and not significant changes in blood loss compared with the conventional group. Complications in the conventional group were the following: minor dural tear in three patients, problematic wound healing in one patient, and insufficient expansion in one patient. Spring-related complications included skin perforation in two patients, a minor dural tear in two patients, and leakage of cerebrospinal fluid after an unnoticed dural tear during spring placement in one patient.

CONCLUSION

Spring-assisted posterior vault expansion has some advantages over the conventional technique and is, therefore, the preferred technique in our center.

Posterior cranial vault expansion in the treatment of craniosynostosis. Comparison of current techniques

INTRODUCTION

Surgical procedures which aim at expanding the posterior cranial vault have come to play an increasingly important role in the treatment of syndromic craniosynostosis. The posterior cranial vault may be expanded by formal cranioplasty or by less invasive methods based on gradual posterior cranial vault expansion or distraction. These procedures share the common goals to prevent intracranial hypertension and progression toward turricephaly by effectively increasing the intracranial volume. They also reduce any local brain compression within the posterior cranial fossa.

PATIENTS AND METHODS

This review describes the various techniques available for less invasive and gradual posterior cranial vault expansion and their rationale based on our experience on the last 40 cases. Volumetric data for three different surgical techniques have been compared (two cases of posterior cranial vault expansion by free-floating parieto-occipital bone flap, two with springs, and two with internal distractors). The volumetric analysis showed an expansion of 13 and 24 % for the free posterior flap, 18 and 25 % for the translambdoid springs, and 22 and 29 % for the distractors.

DISCUSSION

Although these figures are not strictly comparable, our data suggest that these three techniques offer a potential for a significant increase in skull volume. The indications for such procedures must, however, be tailored according to the age and condition of the single patient.