Volumetric Analysis of Anterior Versus Posterior Cranial Vault Expansion in Patients With Syndromic Craniosynostosis:

Spring-assisted posterior vault expansion in children over 2 years of age with craniosynostosis

BACKGROUND

This study evaluated spring-assisted posterior vault expansion (SA-PVE) in children aged > 2 years with craniosynostosis and signs of high intracranial pressure (ICP).

METHODS

We retrospectively analysed all consecutive patients aged > 2 years and operated with SA-PVE between 2018 and 2020 at the Craniofacial Center at Sahlgrenska University Hospital, Sweden. During the procedure, a circumferent occipital bone flap extending below the torcula was created and remained attached to the dura. Intracranial volumes (ICVs) were calculated from computed tomography (CT) images, and demographic data and information regarding symptoms and signs of high ICP were collected.

RESULTS

The study included eight patients [Crouzon/Pfeiffer (n = 4), multiple craniosynostosis (n = 3), and secondary synostosis (n = 1)]. Median age at SA-PVE was 3.8 years (range: 2.5-12.8 years), and springs were removed after a median of 5.5 months (range: 2.3-8.3 months). The median operating time was 164 min (range: 102-221 min), and estimated blood loss was 4.5 mL/kg body weight (range: 1.4-59.1 mL/kg body weight), with 50% of patients receiving a blood transfusion. The median increase in ICV was 206 cm3 (range: 122-344 cm3) representing an 18.7% increase (range: 7.9-24.1%; p = 0.01). We observed no major perioperative complications, and symptoms related to high ICP were improved or absent at clinical follow-up.

CONCLUSION

These results demonstrated that SA-PVE involving creation of a large occipital bone flap including the torcula as a safe and effective surgical treatment in children aged >2 years with craniosynostosis and elevated ICP.

Early posterior vault distraction osteogenesis changes the syndromic craniosynostosis treatment paradigm: long-term outcomes of a 23-year cohort study

BACKGROUND

Early surgical management of syndromic craniosynostosis varies widely between centers, with patients typically undergoing multiple intracranial procedures through childhood. This study evaluates the long-term impact of early posterior vault distraction osteogenesis (PVDO) versus conventional treatment paradigms on the number and timing of subsequent craniofacial procedures.

METHODS

We retrospectively analyzed the longitudinal operative patterns of patients with syndromic craniosynostosis treated from 2000 to 2023 with greater than five years of follow-up. Outcomes of patients who underwent early PVDO and conventional vault reconstruction were compared.

RESULTS

Fifty-five patients met the inclusion criteria (30 PVDO and 25 conventional). Age at initial vault surgery was similar between the PVDO and conventional cohorts (7.6 vs. 8.8 months), as were baseline craniometrics (p > 0.05). Multiple fronto-orbital advancement (FOA) procedures were performed in only 1/30 (3%) PVDO-treated patient versus 12/25 (48%) conventionally-treated patients (p < 0.001). Twelve (40%) PVDO-treated patients did not undergo FOA at all. Among patients with Apert and Crouzon syndromes, fewer PVDO-treated patients required FOA prior to midface surgery (33% vs. 92%, p = 0.004) or repeat FOA (6% vs. 50%, p = 0.005) compared to conventionally-treated patients. Among patients with Muenke and Saethre-Chotzen syndromes, a similar proportion of patients required FOA in the PVDO and conventional cohorts (91% vs. 100%, p = 0.353), though no PVDO-treated patients required repeat FOA (0% vs. 44%, p = 0.018).

CONCLUSIONS

Early PVDO is associated with a reduction in the high burden of both FOA and, critically, revisionary frontal procedures which are commonly seen in conventionally-treated patients with syndromic craniosynostosis.

Vaulting further: cranial vault expansion for craniocerebral disproportion without primary craniosynostosis

PURPOSE

Treatment of subjects with refractory idiopathic intracranial hypertension (IIH) or shunted hydrocephalus with chronic shunt complications is challenging. What is the role for cranial vault expansion, particularly utilizing posterior vault distraction osteogenesis (PVDO), in these cases? This study assesses medium-term efficacy of cranial vault expansion in this unique patient population.

METHODS

A retrospective review was conducted of patients who underwent cranial vault expansion from 2008 to 2023 at the Children's Hospital of Philadelphia. Subjects who did not have a diagnosis of primary craniosynostosis were included in the study. Demographic information, medical history, and perioperative details were collected from medical records. Primary outcomes were the rate of CSF diversion procedures and resolution of presenting signs and symptoms. Secondary outcomes were perioperative and 90-day complications and reoperation requirement.

RESULTS

Among 13 included subjects, nine (69.2%) patients had a primary diagnosis of shunted hydrocephalus and 4 (30.8%) patients had IIH. Twelve (92.3%) subjects underwent posterior vault distraction osteogenesis (PVDO) and one (7.7%) underwent posterior vault remodeling (PVR). All 4 patients with IIH demonstrated symptomatic improvement following PVDO, including resolution of headaches, vomiting, and/or papilledema. Among 9 patients with shunted hydrocephalus, CSF diversion requirement decreased from 2.7 ± 1.6 procedures per year preoperatively to 1.2 ± 1.8 per year following cranial vault expansion (p = 0.030). The mean postoperative follow-up was 4.1 ± 2.1 years and four (30.8%) patients experienced complications within 90 days of surgery, including infection (n = 2), CSF leak (n = 1), and elevated ICP requiring lumbar puncture (n = 1). Four (30.8%) patients underwent repeat cranial vault expansion for recurrence of ICP-related symptoms. At most recent follow-up, 7 of 9 patients with shunted hydrocephalus demonstrated symptomatic improvement.

CONCLUSION

Cranial vault expansion reduced intracranial hypertension-related symptomology as well as the rate of CSF diversion-related procedures in patients with refractory IIH and shunted hydrocephalus without craniosynostosis, and should be considered in those who have significant shunt morbidity.

Posterior cranial vault distraction in children with syndromic craniosynostosis: the era of biodegradable materials-a comprehensive review of the literature and proposed novel global application

Distraction osteogenesis is utilized to increase intracranial volume in the treatment of restrictive pathologies, most commonly syndromic synostosis. Children too young for open calvarial vault expansion or other systemic or local contraindications to a direct reconstructive approach benefit greatly from distraction osteogenesis, typically addressing posterior vault expansion. Wound infection, cerebrospinal fluid (CSF) leak, device failure, need for a second surgery for removal, and cost, are issues that can limit the use of this approach. These challenges are more pronounced in low- and middle-income countries (LMICs) due to lack of access to the device, the financial burden of the need for a second surgery, and the severity of the implications of infection and CSF leak. Over the last five decades, there has been an increased acceptance of bioresorbable instrumentation in craniofacial surgery. Poly L-lactic acid, polyglycolic acid, and polydioxanone are the most commonly used polymers. New resorbable fixation tools such as ultrasound-activated pins and heat-activated pins are superior to conventional bioresorbable screws in allowing attachment to thinner bone plates. In this paper, we present a review of the literature on cranial vault distraction and the use of bioresorbable materials and propose a novel design of a fully absorbable cranial distractor system using external magnetic distraction control, eliminating the need for external activation ports and a second surgery to remove the hardware. The application of this technology in LMIC settings could advance access to care and treatment options for patients with syndromic synostosis.

Oxycephaly-systematic review, case presentation, and diagnostic clarification

PURPOSE

Oxycephaly is a specific phenotype of multi-suture craniosynostosis that is often misrepresented. This study aims to review the relevant literature, clarify the diagnostic criteria, and present an alternate approach to its management.

METHODS

Published literature regarding oxycephaly was reviewed from 1997, when the largest series was published, until 2022. All cases at a single institution were then retrospectively reviewed.

RESULTS

Over the last 25 years, four studies met the inclusion criteria, none of which specifically defined oxycephaly. One case, in one study, was potentially consistent with the phenotype. An institutional review yielded two patients who met the original diagnostic criteria set forth by Renier and Marchac. Both patients had unexplained speech delays, mild retinal nerve fiber layer thickening, and diffuse inner table scalloping, along with the characteristic oxycephalic phenotype. One patient also had a direct intracranial pressure (ICP) measurement of 25 mmHg, and the other had a Chiari I malformation. Both were treated with posterior vault distraction osteogenesis (PVDO) to alleviate the cephalo-cranial disproportion while simultaneously allowing for turricephaly correction.

CONCLUSIONS

Oxycephaly presents with late onset multi-suture fusion. Patients have patent sutures at birth. Midface hypoplasia and known syndromic associations are absent. Patients demonstrate supraorbital recession, an obtuse fronto-nasal angle, and turricephaly without substantial brachycephaly. Over 60% of patients have symptomatic ICP elevation, the presentation of which ranges from headaches to rapidly progressive blindness. This rare form of craniosynostosis is particularly virulent and likely often missed due to diagnostic ambiguity and its relatively mild phenotype.

Spring-Assisted Cranial Expansion for Multisuture Craniosynostosis: First Case Report from the Indian Subcontinent

We present a first use case report from the Indian subcontinent of a 5-month-old child with multisuture craniosynostosis with raised intracranial pressure managed by spring-assisted cranial expansion followed by traditional fronto-orbital advancement and cranial vault remodeling. We emphasize the advantages of spring-assisted cranial expansion in extremely young infants with raised intracranial pressure over posterior vault distraction osteogenesis and open posterior vault remodeling.

Does the Mutation Type Affect the Response to Cranial Vault Expansion in Children With Apert Syndrome?

LEVEL OF EVIDENCE

III.

Comparing the Increased Intracranial Volume From Different Surgical Methods for Syndromic Craniosynostosis

PURPOSE

Fronto-orbital advancement (FOA) is the traditional surgical method used to increase intracranial volume, but posterior cranial vault distraction osteogenesis (PVDO) has been gaining popularity as an initial treatment option. This study aimed to compare the effects of FOA and PVDO on intracranial volume.

PATIENTS AND METHODS

Sixteen patients with multiple-suture synostosis and severe intracranial volume restriction were treated with FOA or PVDO at Children's Hospital of Fudan University between January 2016 and December 2019. Data on age at surgery, sex, preoperative intracranial volume, and postoperative intracranial volume were collected.

RESULTS

Seven patients underwent FOA and 9 underwent PVDO. All patients underwent surgery for the first time, and the surgeries were performed by the same physician. There was no statistically significant difference in age at surgery or in the intracranial volumes before and after surgery between the 2 groups (P>0.05). There was a statistically significant difference in the intracranial volume changes between the 2 groups before and after surgery (P=0.028).

CONCLUSIONS

Posterior cranial vault distraction osteogenesis provided statistically greater intracranial volume expansion than FOA.

Behavioral, Learning Skills, and Visual Improvement in Crouzon Syndrome Patient Following Late Posterior Vault Distraction Osteogenesis

BACKGROUND

It is well accepted among craniofacial surgeons that surgery does not improve mental status but does prevent worsening or deterioration of cognitive and mental function. In this report, we describe significant improvement in behavioral, learning skills and visual acuity for a Crouzon patient who underwent late posteriorvault distraction osteogenesis.

METHODS

A 9-year-old Crouzon patient was referred to our hospital, presenting severe intracranial hypertension. The patient had previously undergone a strip craniectomy in early infancy at another medical institution, but there was no subsequent follow-up. Magnetic resonance imaging showed Chiari type I malformation and fundoscopy revealed papilledema. At the time of referral, the patient was not attending a regular school, had not acquired reading skills, was unable to concentrate, and could not accomplish school-related tasks that were standard for children in his age group.

RESULTS

The patient underwent posterior vault distraction osteogenesis and showed concentration improvement and acquisition of fluent reading skills. Chiari type I malformation resolved as well as papilledema. visual acuity improved at Snellen test preoperatively from 20/200 to 20/60 at postoperative test. Ventricle size remained unchanged subsequent to performance of the posterior cranial vault distraction. The occipital veins were less visible upon clinical examination and less pronounced when palpated, and the bruit had completely disappeared.

CONCLUSION

Late posterior vault distraction osteogenesis can improve behavioral, learning skills and visual acuity as shown in this 9-year-old Crouzon patient.

Early cranial vault distraction for a more balanced and enhanced expansion: a 3D craniometric analysis of anterior versus posterior distraction osteogenesis in patients with craniosynostosis

OBJECTIVE

Posterior distraction osteogenesis (DO) is widely accepted for the treatment of craniosynostosis. The aim of this study was to quantitatively compare the effect of DO on the cranial vault according to the age of the patient and direction of distraction.

METHODS

This was a retrospective study of patients with craniosynostosis who underwent DO in the anteroposterior direction. Postdistraction changes in intracranial volume (ICV), anteroposterior distance, biparietal distance, cranial height, and frontal bossing angle were measured using Mimics software on CT scans. Craniometric data were analyzed using a multivariate regression model.

RESULTS

Thirty-two patients (16 anterior and 16 posterior DOs) were included in the study. The mean ICV increase in the anterior and posterior DO group was 211 cm3 (range 142-281 cm3) and 214 cm3 (range 150-279 cm3), respectively. Patients who were aged 1 year or younger showed a greater percentage increase in ICV than patients older than 1 year. In the anterior DO group, a more balanced increase in both anterior and posterior anteroposterior distance was observed in patients aged 1 year or younger when compared to patients older than 1 year. In the posterior DO group, a bigger expansion and smoother contour in the posterior cranial fossa was observed in patients aged 1 year or younger.

CONCLUSIONS

Both anterior and posterior DO are effective surgical options for expanding the cranial vault in patients with craniosynostosis. Early distraction appeared to show greater morphological changes in the growing cranial vault than those predicted with the vector of distraction.

"Ten Years of Posterior Cranial Vault Expansion via Distraction Osteogenesis: An Update and Critical Evaluation"

PURPOSE

The goal of this study was to describe the 10-year evolution of our surgical technique and institutional perioperative outcomes using posterior vault distraction osteogenesis (PVDO) in patients with syndromic and multi-suture craniosynostosis.

METHODS

We performed a retrospective cohort study of patients who underwent PVDO for treatment of syndromic and multi-suture craniosynostosis at a single institution over a 10-year period. Demographic data, perioperative outcomes, distraction patterns, and complications were analyzed. Outcomes for patients in the first 5 years ("early cohort") were compared to those of the latter 5 years ("late cohort").

RESULTS

110 patients underwent a total of 118 PVDO procedures. Syndromic patients represented 83.6% of the cohort (n=92) and were significantly younger than non-syndromic patients at the time of first PVDO (median 14.1 [6.6, 40.1] vs 42.7 [15.2, 59.6] months, p=0.014). Mean distraction distance in the anterior-posterior direction was 30.8 mm (SD=7.4). Compared to the early cohort, PVDO in the late cohort had faster median operative times (144.0min [123.0, 189.0] vs 161.0min [138.0, 199.0], p=0.038), lower estimated blood loss as a percent of blood volume (28.5 [20.6, 45.3] vs 50.0 [31.1, 95.8], p<0.001), and lower blood replacement as percent of blood volume (39.5 [23.8, 59.1] vs 56.3 [37.8, 110.1], p=0.009).

CONCLUSIONS

Our 10-year experience with PVDO demonstrates continued overall safety and efficacy with improved perioperative outcomes over time. While it has become our first line of expansion in syndromic craniosynostosis, shortcomings such as need for device removal, infectious concerns, and potential for CSF leak merit attention by the craniofacial community.

Posterior Vault Distraction Outcomes in Patients with Severe Crouzon Syndrome Resulting from Ser347Cys and Ser354Cys Mutations

BACKGROUND

In this study, the authors present the outcomes of 4 patients with a severe form of Crouzon syndrome characterized by mutation of fibroblast growth factor receptor 2 (FGFR2) c.1040 C > G p.Ser347Cys or the pathogenic c.1061C > G p.Ser354Cys variant of FGFR2, who underwent posterior vault distraction osteogenesis (PVDO) to alleviate elevated intracranial pressure.

METHODS

Patients with diagnosed Crouzon syndrome who were found by genetic testing to have an FGFR2 c.1040 C > G p.Ser347Cys mutation or the c.1061C > G p.Ser354Cys variant were included. Outcome data and presence of hydrocephalus, Chiari Malformation type I (CMIs), and the presence/absence of a tracheostomy were recorded.

RESULTS

Three patients with the FGFR2 c.1040 C > G p.Ser347Cys mutation and 1 with the pathogenic FGFR2 c.1061C > G p.Ser354Cys variant were identified as having characteristics of severe Crouzon syndrome. The mean age at PVDO was 15 months and the mean posterior advancement was 20 mm. All 4 patients experienced sufficient relief of the elevated intracranial pressure from the PVDO to prevent the need for shunt placement, stabilize the ventricular dimensions (n = 2), and resolve the CMIs (n = 2). Intracranial pressure screening ruled out malignant cerebrospinal fluid volume increase.

CONCLUSIONS

PVDO effectively prevented hydrocephalus and resolved CMIs, successfully alleviating intracranial pressure and maximizing clinical outcomes for patients with severe Crouzon syndrome.

Transverse Distraction Osteogenesis for Posterior Narrowing of the Cranial Vault

SUMMARY

Although conventional posterior vault distraction osteogenesis is known to achieve the greatest improvement in intracranial volume, anteroposterior expansion of the cranial vault is not always ideal in certain head shapes. Transverse posterior vault distraction osteogenesis is an alternative reconstructive strategy in patients presenting with recalcitrant multisuture craniosynostosis resulting in scaphocephaly with posterior narrowing. The authors present a multimedia demonstration of placing the cranial hinge points at the superior anterior aspect of the bone segments in order to achieve increased intracranial volume and significant improvement in posterior head shape, while preserving normal anterior skull dimensions.

Complete posterior cranial vault distraction osteogenesis to correct Chiari malformation type I associated with craniosynostosis

OBJECTIVE

Posterior vault distraction osteogenesis (PVDO) is an effective tool to increase intracranial volume and expand the posterior cranial fossa. During PVDO, the authors extended osteotomy posterior to the foramen magnum to fully expand the posterior cranial fossa. The aim of this study was to investigate the efficacy of complete PVDO in posterior fossa expansion and treatment of Chiari malformation type I (CM-I) in patients with craniosynostosis.

METHODS

Patients with craniosynostosis who had undergone complete PVDO between January 2012 and May 2020 were reviewed retrospectively. A coronal osteotomy extending to the foramen magnum was performed and the foramen magnum was decompressed by removing its posterior rim with a 1-mm Kerrison rongeur. Four distractor devices were placed and the vector of distraction was controlled from the posterior to the inferior-posterior direction, depending on the deformity. Changes in the intracranial volume, posterior cranial fossa area, and cerebellar tonsillar descent were measured after complete PVDO by using CT and MRI.

RESULTS

A total of 11 patients with craniosynostosis and concurrent CM-I were included in the study. The mean age was 34.6 ± 24.0 months (continuous variables are expressed as the mean ± SD throughout). One patient had sleep apnea, which was consistent with CM-I, and another patient had a headache, which was nonspecific. The intracranial volume increased from 1179.6 ± 180.2 cm3 to 1440.6 ± 251.5 cm3 (p = 0.003; 24.5% increase compared to the preoperative volume). The posterior skull base area increased from 44.9 ± 19.3 cm2 to 72.7 ± 18.1 cm2 (p = 0.004). Cerebellar tonsillar descent decreased in all 11 patients after complete PVDO (preoperative: 10.8 ± 3.7 mm, postoperative: 2.7 ± 3.0 mm; p = 0.003). Among the 11 patients, 5 showed complete resolution of cerebellar tonsillar herniation.

CONCLUSIONS

Complete PVDO can more efficiently expand the posterior cranial fossa, unlike conventional methods. Moreover, it helps to relieve cerebellar tonsillar herniation. Complete PVDO is a powerful tool to increase the intracranial and posterior fossa volumes in patients with craniosynostosis and concurrent CM-I.

Syndromic Craniosynostosis: Unique Management Considerations

Craniosynostosis involves the premature fusion of 1 or more cranial sutures and commonly presents as an isolated, nonsyndromic diagnosis. A subset of patients have syndromic craniosynostosis. Several unique considerations must be taken into account when managing patients with syndromic craniosynostosis. A multidisciplinary craniofacial team with a central coordinator is particularly useful for coordinating care among various specialists, and close monitoring is mandatory owing to the increased risk of intracranial hypertension. Surgical management varies among centers, but core options include fronto-orbital advancement with cranial vault remodeling, posterior vault expansion, endoscopic-assisted suturectomy with postoperative orthotic therapy, and midface advancement.

Morbidity Associated With Anterior Versus Posterior Cranial Vault Expansion for Early Treatment of Syndromic Craniosynostosis: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of this systematic review and meta-analysis was to estimate and compare rates of unplanned reoperation and complications after undergoing either fronto-orbital advancement (anterior cranial vault expansion) or posterior cranial vault expansion as an early surgery in the management of syndromic craniosynostosis.

MATERIALS AND METHODS

A literature search was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Relevant articles were identified in 2 electronic databases (PubMed and EMBASE) from the time of electronic publication to November 2020. Quality assessment and risk of bias were appraised using the Grading of Recommendations Assessment, Development and Evaluation system. A meta-analysis was performed comparing rates of reoperation and complications between participants who underwent anterior or posterior cranial vault expansion as an early surgery.

RESULTS

Of 1,373 screened records, 7 met inclusion criteria. Six were included in the meta-analysis. The studies that met inclusion criteria reported on 103 patients treated with anterior techniques and 72 patients treated with a posterior approach. Anterior cranial vault expansion was associated with significantly higher rates of reoperation (Peto odds ratio = 2.83; 95% confidence interval = 1.19, 6.74, P = .02) and complications (Peto odds ratio = 2.61; 95% confidence interval = 1.12, 6.12, P = .03) than posterior cranial vault expansion.

CONCLUSIONS

Both anterior and posterior approaches are suitable options in the treatment of syndromic craniosynostosis depending on patient-specific factors. Anterior cranial vault expansion was associated with higher rates of unplanned reoperation and complications than posterior techniques in this analysis. Because of the paucity of literature which met inclusion criteria, this study was not able to assess critical outcome variables such as distance distracted/volumetric expansion, estimated blood loss, and cost. Larger studies evaluating both techniques under multiple institutions with long-term follow-up are indicated.

Intracranial Volume Measured and Correlated to Cephalic Index in Syndromic and Nonsyndromic Anterior Brachycephaly

BACKGROUND

Premature fusion of both coronal sutures (anterior brachycephaly) alters skull shape and potentially affects intracranial volume (ICV). Currently little is known about preoperative ICV in anterior brachycephaly. Aim is to measure preoperative ICV and compare this with normative data. Additionally, ICV will be correlated to most used clinical method of quantification: cephalic index (CI).

METHODS

Preoperative patients with anterior brachycephaly (age, ≤12 months) were included and categorized by syndrome (when present). Computed tomography scans were used for ICV measurement by manual segmentation (OsiriX (Fondation OsiriX, Geneva, Switzerland)). Intracranial volume of each subgroup was compared with Lichtenberg normative cranial volume growth curves for controls. Cephalic index was calculated and correlated to ICV using Pearson correlation coefficient.

RESULTS

Thirty-four patients with both syndromic and nonsyndromic anterior brachycephaly were included: 17 with Apert syndrome, 6 with Muenke syndrome, 5 with Saethre Chotzen syndrome, 3 with Crouzon, 1 with craniofrontonasal dysplasia, and 2 nonsyndromal. Mean age at preoperative computed tomography scan was 4 months (1-10 months). Mean ICV was 847.31 cm3 (473.91-1459.22 cm3). Nineteen of 34 patients had skull volumes between ±2 SD curves of Lichtenberg, none of the patients had an ICV smaller than -2 SD and 15 of 34 had an ICV larger than +2 SD. Mean ICV in Apert syndrome was 829.85 cm3 (473.91-1061.53 cm3), in Muenke syndrome 942.06 cm3 (768.02-1136.75 cm3), in Saethre Chotzen syndrome 779.72 cm3 (609.21-1002.95 cm3), in Crouzon syndrome 700.57 cm3 (652.31-784.32 cm3), in craniofrontonasal dysplasia 738.97 cm3, and in the nonsyndromal group 1154.64 cm3 (850.07-1459.22 cm3). Apert had a mean greater than +2SD above the mean, the other subgroups had a mean within normal ranges (±2 SD). Correlation between severity of brachycephaly and overall ICV was low (r = 0.42).

CONCLUSIONS

Mean preoperative ICV in both syndromic and nonsyndromic anterior brachycephaly was 847.31 cm3. Intracranial volume in anterior brachycephaly is in 55.9% between normal ranges (±2 SD). In 44.1% ICV was greater than +2 SD, especially in Apert syndrome (11/16 Apert patients). None of the included patients had a deviant small ICV of less than -2 SD. Additionally, low correlation between ICV and CI (r = 0.42) was found and therefore CI is not suitable for estimating ICV in anterior brachycephaly.

Conventional posterior cranial vault expansion: indications and results-review of the literature

In the late 1980s, craniofacial surgery units reported suboptimal cosmetic results, cranial volume restriction, and intracranial hypertension after anterior cranial vault remodeling in bilateral coronal synostosis associated with severe brachyturricephaly. A possible explanation was a severe associated growth restriction of the posterior calvaria with radiological synostosis at the lambda sutures. "Conventional" or "fixed" posterior cranial vault expansion techniques were developed to address these limitations, sometimes as the first surgical step in a two-staged protocol of total calvarial reconstruction, combined with suboccipital decompression in cases of symptomatic cerebellar tonsillar herniation or, more easily, to resolve the characteristic occipital flattening of lambdoid synostosis. Various surgical approaches have been described; however, the indications for and timing of surgical treatment and postoperative evaluation of results still remain controversial. Although more invasive, conventional posterior cranial vault expansion has proven to be safe and offers a remodeled and protective bony vault immediately after surgery, but the underlying cranial base malformation remained untreated, with implications in the postoperative growth of the facial skeleton. Overcorrection, rigid stabilization, and grafting are also concerns to be addressed.

Posterior vault distraction osteogenesis: indications and expectations

Cranial vault remodeling (CVR) in patients with craniosynostosis serves to correct abnormal skull morphology and increase intracranial volume to prevent or treat pathologic increases in intracranial pressure (Taylor and Bartlett, Plast Reconstr Surg 140: 82e-93e, 2017). Distraction osteogenesis is a well-established technique for bony repositioning and growth stimulation in the facial and long bones, in which the gradual separation of bony segments at an osteotomy site results in generation of new bone and subsequent bone lengthening (Greene, 2018). While initially described in the orthopedic literature, the relevance and applicability of distraction osteogenesis to craniofacial surgery has been well-studied and is now well-established (Steinbacher et al., Plast Reconstr Surg 127: 792-801, 2011). Posterior cranial vault distraction osteogenesis (PVDO) was introduced as a treatment option for cranial vault expansion in patients with craniosynostosis in 2009 by White et al., based upon the premise that posterior vault distraction could provide greater intracranial volume expansion than fronto-orbital advancement and remodeling (FOAR), but that acute posterior cranial vault expansions were limited by the soft tissue envelope of the infant scalp and prone to relapse related to the supine positioning typical of infants (White et al., Childs Nerv Syst 25: 231-236, 2009). Since this introduction, significant evidence has accrued regarding the safety of, and outcomes after, PVDO. PVDO is now known to provide larger increases in intracranial volume in comparison to anterior cranial vault remodeling procedures (Derderian et al., Plast Reconstr Surg 135:1665-1672, 2015) and to provide morphologic improvements in both the posterior and anterior cranial vaults (Goldstein et al., Plast Reconstr Surg 131:1367-1375, 2013). Perioperative major morbidity is comparable to conventional vault remodeling (Taylor et al., Plast Reconstr Surg 129:674e-680e, 2012) and the procedure has been safely applied to patients of various ages with syndromic and non-syndromic craniosynostosis (Zhang et al., J Craniofac Surg 29:566-571, 2018; Li et al., J Craniofac Surg 27:1165-1169, 2016). Many high-volume craniofacial centers now consider PVDO the preferred first operation in infants with syndromic craniosynostosis, and indications for this procedure continue to expand as evidence accrues regarding its utility and safety (Steinbacher et al., Plast Reconstr Surg 127: 792-801, 2011; Swanson et al., Plast Reconstr Surg 137:829e-841e, 2016).

The Expanding Role of Posterior Vault Distraction Osteogenesis in Idiopathic Intracranial Hypertension and Slit Ventricle Syndrome

ABSTRACT

The purpose of this study was to compare perioperative safety and efficacy of posterior vault distraction osteogenesis (PVDO) in patients with primary nonsynostotic cephalo-cranial disproportion, namely slit ventricle syndrome and idiopathic intracranial hypertension (IIH), to a cohort of patients with craniosynostosis (CS). A retrospective review of patients undergoing PVDO from 2009 to 2019 at our institution was performed. Craniosynostosis patients were matched by sex and age at PVDO to the nonsynostotic cohort. Operative details, perioperative outcomes, and distraction patterns were analyzed with appropriate statistics. Nine patients met inclusion criteria for the non-CS cohort. Six patients (67%) underwent PVDO for slit ventricle and the remaining 3 patients (33%) underwent PVDO for IIH. The majority of CS patients were syndromic (n = 6, 67%) and had multisuture synostosis (n = 7, 78%). The non-CS cohort underwent PVDO at a median 56.1 months old [Q1 41.1, Q3 86.6] versus the CS cohort at 55.7 months [Q1 39.6, Q3 76.0] (P = 0.931). Total hospital length of stay was longer in the non-CS patients (median days 5 [Q1 4, Q3 6] versus 3 [Q1 3, Q3 4], P = 0.021). Non-CS patients with ventriculoperitoneal shunts had significantly less shunt operations for ICP concerns post-PVDO (median rate: 1.74/year [Q1 1.30, Q3 3.00] versus median: 0.18/year [Q1 0.0, Q3 0.7]; P = 0.046). In this pilot study using PVDO to treat slit ventricle syndrome and IIH, safety appears similar to PVDO in the synostotic setting. The cohort lacks adequate follow-up to assess long term efficacy, although short-midterm follow-up demonstrates promising results with less need for shunt revision and symptomatic relief. Future studies are warranted to identify the preferred surgical approach in these complex patients.

Posterior Cranial Vault Distraction Osteogenesis Utilizing a Posterior-Superior Distraction Vector in the Treatment of Mercedes Benz Pattern Craniosynostosis

ABSTRACT

Bilateral lambdoid and sagittal synostosis, or Mercedes Benz Syndrome, is a rare complex craniosynostosis resulting in frontal bossing, a tapered posterior fossa, and an anteriorly displaced cranial vertex. Its ideal surgical correction must result in posterior expansion, skull elongation, and caudal repositioning of the vertex. We present a craniometric analysis of skull changes with posterior-superior distraction and introduce a novel craniometric measure: vertex position. In this study, a retrospective review was performed to analyze outcomes of posterior cranial vault distraction osteogenesis (PVDO) using a posterior-superior distraction vector from 2016 to 2019. Cranial vertex position was measured as a fraction of the occipitofrontal diameter from rostral to caudal (0-1.0). Four patients underwent PVDO at mean age 10.61 ± 3.16 months utilizing a posterior-superior distraction vector. Linear distraction distance averaged 30.30 ± 0.90 mm with a mean consolidation period of 3.98 ± 0.72 months. Mean corrected change in intra-cranial volume was 236.30 ± 3.71 mL, at an average rate of 7.81 ± 2.00 mL/mm of distraction. Increases in anterior cranial height (7.83 ± 2.51 mm), middle cranial height (8.43 ± 4.21 mm), posterior cranial height (13.15 ± 7.45 mm), and posterior cranial fossa height (21.99 ± 8.55 mm) were observed. Cranial vertex demonstrated a mean posterior movement of 0.18 ± 0.13. PVDO utilizing a posterior-superior distraction vector for management of nonsyndromic bilateral lambdoid and sagittal synostosis effectively increases intracranial volume and height and provides an esthetic outcome with posterior movement of the cranial vertex.

Respective Roles of Craniosynostosis and Syndromic Influences on Cranial Fossa Development

BACKGROUND

Little is known about the detailed growth of the cranial fossae, even though they provide an important structural connection between the cranial vault and the facial skeleton. This study details the morphologic development of isolated cranial vault synostosis and associated syndromes on cranial fossa development.

METHODS

A total of 125 computed tomographic scans were included (nonsyndromic bicoronal synostosis, n = 36; Apert syndrome associated with bicoronal synostosis, n = 24; Crouzon syndrome associated with bicoronal synostosis, n = 11; and controls, n = 54). Three-dimensional analyses were produced using Materialise software.

RESULTS

The regional anterior and middle cranial fossae volumes of nonsyndromic bicoronal synostosis are characterized by significant increases of 43 percent (p < 0.001) and 60 percent (p < 0.001), respectively, and normal posterior cranial fossa volume. The cranial fossae depths of nonsyndromic bicoronal synostosis were increased, by 37, 42, and 21 percent (all p < 0.001) for anterior, middle, and posterior cranial fossae, respectively, accompanying the shortened cranial fossae lengths. The volume and morphology of all cranial fossae in Apert syndrome nearly paralleled nonsyndromic bicoronal synostosis. However, Crouzon syndrome had reduced depths of cranial fossae, and more restricted fossa volumes than both Apert syndrome and nonsyndromic bicoronal synostosis.

CONCLUSIONS

Cranial vault suture synostosis is likely to be more influential on cranial fossae development than other associated influences (genetic, morphologic) in Apert and Crouzon syndromes. Isolated Apert syndrome pathogenesis is associated with an elongation of the anterior cranial fossa length in infants, whereas in Crouzon syndrome, there is a tendency to reduce cranial fossa depth, suggesting individual adaptability in cranial fossae development related to vault synostosis.

Fronto-Orbital Advancement and Posterior Cranial Vault Expansion Using Distraction Osteogenesis in Patients With Multiple Craniosynostosis

ABSTRACT

This study aimed to evaluate the treatment outcomes and the efficiency of techniques of fronto-orbital advancement (FOA) and posterior cranial vault expansion (PCVE) using distraction osteogenesis in patients with multiple craniosynostosis. We assessed the treatment results and outcomes of 8 patients with multiple craniosynostosis at the Kagoshima University Hospital between 2005 and 2019. Each 4 patients underwent FOA and PCVE, respectively, using distraction osteogenesis. The cranial volume and developmental quotient (DQ) were measured at the preoperative period and 1 year after surgery. The mean patient age at surgery was 22 months. The mean preoperative cranial volume was 1027 and 1071 cm3 in the FOA and PCVE groups, respectively. The mean preoperative DQ scores were 74 and 67, respectively. After 1-year of follow-up, the corresponding mean cranial volume became 1108 and 1243 cm3, respectively. The corresponding mean DQ scores also improved to 74 and 81, respectively. The postoperative follow-ups in all cases were uneventful, except for persistent epilepsy in 1 patient. Fronto-orbital advancement and PCVE using distraction osteogenesis might contribute to good outcomes in expanding cranial volume, cosmetic osteogenesis, and infantile development in patients with multiple craniosynostosis. Regarding the cranial volume expansion, especially, PCVE using distraction osteogenesis is more effective than FOA.

Risk Factors for Occipital Step-Off Deformities in Posterior Vault Distraction Osteogenesis

PURPOSE

The goal of this study was to investigate patient specific factors and surgical techniques that affect occipital step-off deformity in children undergoing posterior vault distraction osteogenesis (PVDO).

METHODS

Patients who underwent PVDO were retrospectively reviewed and included if a high resolution three-dimensional computed tomography scan was available 1-year post-distractor removal. Two craniofacial surgeons were blinded to individual subjects and presented with 3 still images of three-dimensional bone reconstructions and asked to rate the degree of step off: none, mild, moderate, or severe. The data were analyzed with multinomial logistic regressions and other appropriate statistics.

RESULTS

Forty-one patients met inclusion criteria. All patients had multisuture or bicoronal craniosynostosis. Multinomial logistic regression identified age at PVDO (Cox and Snell = 0.487, P < 0.001) as a predisposing factor and one potentially protective factor, height of osteotomy (Cox and Snell = 0.394, P = 0.004) in univariate models. Post-hoc pairwise Mann-Whitney U test revealed there was decreased step-off rating when comparing osteotomy below torcula (median 0, [IQR 0, 3]) and above torcula (median 3 [IQR 1, 4]; P = 0.036) as well as a decreased step-off when below inion (median 0 [IQR 0, 1]; P = 0.001) was compared to above the torcula.

CONCLUSIONS

Older age at PVDO predict increased risk of developing an occipital step-off deformity after PVDO, while design of the occipital osteotomy below the inion is protective. Barrel staves with greenstick outfracture did not lower the risk of occipital step-off in this sample, the reasons for which are unclear.

Apert Syndrome Outcomes: Comparison of Posterior Vault Distraction Osteogenesis Versus Fronto Orbital Advancement

BACKGROUND

Presenting a wide clinical spectrum and large variety of clinical features, successful treatment of Apert syndrome necessitates performance of sequential multiple surgeries before a patient's facial skeleton growth is complete.The objective of this study is to compare forehead contour asymmetry and clinical outcomes between Apert patients who underwent either fronto-orbital advancement (FOA) or posterior vault distraction osteogenesis (PVDO).

METHODS

A retrospective study was performed on consecutive patients with Apert syndrome who underwent either FOA or PVDO between 2007 and 2019, and participated in at least 6 months of follow-up care. Forehead contour asymmetry and surgical outcomes for each of the included patients were verified through medical records, clinical photographs, and interviews with the parents of the patients. The need for additional craniofacial procedures based on the surgical outcomes of each patient was graded from I to IV utilizing the Whitaker outcome classification system.

RESULTS

Forehead contour asymmetry for all included patients was rated under the Whitaker grading scale as type II (n = 4) 44.4%, type III (n = 2) 22.2%, and type IV (n = 3) 33.3% for FOA, and type I (n = 5) 35.7%, type II (n = 7) 50%, and type III (n = 2) 14.3%, for PVDO (P < 0.05). The average transfused blood volume was 47.77 ± 9.42 mL/kg for patients who underwent FOA, and 22.75 ± 10.31 mL/kg for patients who underwent PVDO (P < 0.05).

CONCLUSIONS

Patients who underwent PVDO had lower forehead contour asymmetry as per the Whitaker outcome grading scale than patients who underwent FOA.

Posterior cranial vault distraction osteogenesis in the immunocompromised patient

PURPOSE

The treatment of patients with multisuture craniosynostosis is complex and patient-dependent. Cranial distraction osteogenesis is a relatively new procedure for treatment of these patients, with its use increasing in many centers. With this increased use comes an expanding range of indications. Surgical management of multisuture craniosynostosis in therapeutically immunosuppressed patients following a solid organ transplant presents unique challenges. We describe our experience with posterior cranial vault distraction in two patients with multisuture craniosynostosis that had previously undergone organ transplantation.

METHODS

Two solid-organ transplant recipient patients with multisuture craniosynostosis were identified. A detailed examination of their medical/transplant history and perioperative details were recorded.

RESULTS

The first patient was a 3-year-old girl who received a kidney transplantation in infancy and subsequently presented with a symptomatic Chiari malformation and papilledema. Imaging revealed pansynostosis. She underwent posterior cranial vault distraction extending into a Chiari decompression. Her postoperative course was complicated by distractor site infection at the beginning of consolidation, necessitating early removal of distractors. The second patient was a 2-year-old boy who received a heart transplantation at the age of 3 months and subsequently presented with head shape concerns. Imaging revealed bicoronal and sagittal craniosynostosis. He underwent a posterior cranial vault distraction without complication. Following removal of the distractors, he developed an infection at one of the distractor sites with associated fever and leukocytosis, necessitating washout and drain placement. Both patients achieved successful cranial vault expansion with distraction osteogenesis and at a 2-year follow-up do not have evidence of elevated intracranial pressure.

CONCLUSIONS

Immunosuppressive therapy has the potential to inhibit wound healing and place patients at risk for wound infection. Although we have demonstrated successful cranial vault expansion with distraction in two immunosuppressed children, extra care must be taken with these patients when placing semi-buried hardware. Specifically, prompt identification and proactive management of potential infectious complications is critical to applying this technique safely in these patients.

Severe craniolacunae and upper and lower extremity anomalies resulting from Crouzon syndrome, FGFR2 mutation, and Ser347Cys variant

Crouzon syndrome is a rare form of syndromic craniosynostosis (SC) characterized by premature fusion of the cranial and facial sutures, elevated intracranial pressure, varying degrees of ocular exposure due to exorbitism, and airway compromise caused by midface retrusion. Craniolacunae and upper and lower extremity anomalies are not frequently found in Crouzon syndrome. We present a girl with Crouzon syndrome caused by c.1040 C > G, p.Ser347Cys, a pathogenic mutation in the FGFR2 gene with atypical characteristics, including craniolacunae resembling severe Swiss cheese type of bone formation, and upper and lower extremity anomalies which are more commonly associated with Pfeiffer syndrome patients. Distinguishing between severe Crouzon syndrome patients and patients who have mild and/or moderate Pfeiffer syndrome can be challenging even for an experienced craniofacial surgeon. An accurate genotype diagnosis is essential to distinguishing between these syndromes, as it provides predictors for neurosurgical complications and facilitates appropriate family counseling related to long-term outcomes.

Craniometric and Volumetric Analysis of Posterior Vault Distraction Osteogenesis: 10 Year Update

PURPOSE

The purpose of this study is to quantitatively establish the volumetric changes observed with posterior vault distraction osteogenesis in the anterior, middle, and posterior thirds of the cranial vault; characterize change in cranial length, width, and height, correlating these changes to demographic variables that may help identify why younger kids gain more volume; and describe the short-term position of the transport segment.

METHODS

Multisuture craniosynostosis patients who underwent posterior vault distraction osteogenesis were retrospectively reviewed. Pediatric, dose-reduced, thin cut helically acquired head computed tomography scans were analyzed on Materialise Mimics v22 (Materialise, Ghent, Belgium). Pre and post-PVDO and "old" and "young" cohort were compared.

RESULTS

Twenty-one patients met inclusion criteria. The change in cranial length was significantly less at a median of 14.9 mm [Interquartile range (IQR) 11.8, 31.6] compared to the X-ray measured AP distraction distance (30 mm [IQR 24, 33]; P < 0.001) and significantly less than the theoretically calculated distance (23 mm [IQR 19, 31]; P = 0.012). Median anterior cranial height was shorter post PVDO (82.9 mm, [IQR 64.8, 92.6] versus 78.7 mm [IQR 57.0, 88.7]; P = 0.030). The younger cohort saw a greater increase in total intracranial volume (median 335.1 mL [IQR 163.2, 452.3, median 37.1%] versus 144.6 mL [IQR 119.0, 184.8, median 12.0%]; P = 0.011).

CONCLUSIONS

This is the first study to quantify volumetric changes to the anterior, middle, and posterior cranial vaults and demonstrates benefits of preforming PVDO at a younger age to help control turricephaly and produce greater percentage volumetric increases.

A Review on Variability in Treatment Protocols With Posterior Cranial Vault Distraction

BACKGROUND

Prior studies have confirmed the ability of posterior cranial vault distraction osteogenesis (PVDO) to expand the intracranial volume in patients with craniosynostosis. To date, there is scant literature on the optimal distraction protocol for PVDO. The authors sought to review the literature and define a common protocol for posterior cranial vault distraction.

METHODS

The authors performed a systematic review for published PVDO protocols. The data collected from these studies included age at the time of PVDO, number of distraction devices placed, time for latency, rate and rhythm of distraction, distraction length, time for consolidation, and surgical outcomes.

RESULTS

A total of 286 patients were identified within 24 studies from 2011 to 2019. The mean age of patients identified was 25.34 months. After application of distractors, latency period ranged between 1 and 7 days, with most patients undergoing 5 to 7 days of latency. Once distraction was begun, the majority of patients (77.4%) underwent 1 mm of distraction daily. Total lengths of distraction ranged between 13 and 35 mm, with the largest cohort of patients undergoing 26 to 30 mm of total distraction. A total of 60 complications were reported for a total of 212 patients, yielding an overall complication rate of 28.3%.

CONCLUSIONS

Although there is variability in reported PVDO protocols, the majority are similar to distraction osteogenesis protocols described for long bone sites. Increased patient age correlates with selection of a greater latency period and total distraction length, while frequency of complications is also increased.

Serial Posterior Cranial Vault Distraction for the Treatment of Complex Craniosynostosis

ABSTRACT

Posterior cranial vault distraction is an important modality in the management of craniosynostosis. This surgical technique increases intracranial volume and improves cranial aesthetics. A single procedure is often inadequate in patients with complex multisuture craniosynostosis, as some will go on to develop intracranial hypertension despite the operation. Considering the negative effects of intracranial hypertension, some patients may warrant 2 planned distractions to prevent this scenario from ever occurring. Three patients with complex multiple-suture synostosis and severe intracranial volume restriction (occipital frontal head circumferences [OFCs] <1st percentile) were treated with 2 planned serial posterior cranial vault distractions at the institution between 2013 and 2018. Demographics, intraoperative data, and postoperative distraction data were collected. The OFC was recorded pre- and postdistraction, at 3- and 6-month follow-up appointments. Patients had a corrected average age of 18 weeks at the time of their initial procedure. There was an average of 38 weeks between the end of consolidation and the time for their 2nd distraction procedure. There was an average age of 79 weeks at the time of the 2nd procedure. All patients had a substantial increase in OFC and improvement of the posterior calvarium shape. The average increase in OFC was 5.2 cm after first distraction and 4.3 cm after 2nd distraction. No postoperative complications were encountered. Planned serial posterior cranial vault distraction is a safe and effective strategy for increasing intracranial volume, improving aesthetic appearance, and preventing the consequences of intracranial hypertension in patients with multisuture craniosynostosis and severe intracranial volume restriction.

Syndrome-related outcomes following posterior vault distraction osteogenesis

PURPOSE

The most commonly occurring syndromic craniosynostoses are Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, and Saethre-Chotzen syndrome. There is insufficient data regarding postoperative syndrome-related outcomes following the posterior vault distraction osteogenesis (PVDO) procedure, as well as data addressing whether or not additional procedures will be subsequently necessary to comprehensively treat children who undergo PVDO. Thus, the objective of this study is to describe and compare syndrome-related potential complications and outcomes associated with the PVDO procedure.

METHODS

An observational retrospective study was performed on consecutive patients (n=24) with Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, or Saethre-Chotzen syndrome, respectively, who underwent PVDO between 2012 and 2019. Demographic data (patient gender and age when the PVDO procedure was performed), diagnosis, surgery-related data, and outcome data (perioperative and midterm complications and need for additional surgery) were verified.

RESULTS

Total relative blood transfusion volumes per kilogram for the patients were as follows: 22.75 ± 9.30 ml for Apert syndrome, 10.73 ± 2.28 ml for Crouzon syndrome (Apert versus Crouzon, p<0.05), 18.53 ± 8.08 ml for Pfeiffer syndrome, and 19.74 ± 9.12 ml for Saethre-Chotzen syndrome. None of the patients required a secondary procedure to alleviate intracranial pressure except for a Saethre-Chotzen patient.

CONCLUSION

PVDO is an effective technique to address elevated intracranial pressure in SC patients that alleviates the need for secondary procedures at midterm follow-up. Apert syndrome patients presented relatively higher total blood transfusion rates than Crouzon syndrome patients who were operated on at a later age and weighed more.

Craniosynostosis: Posterior Cranial Vault Remodeling

Posterior cranial vault distraction osteogenesis is a powerful, reliable, low-morbidity method to achieve intracranial expansion. It is particularly useful in treating turribrachycephaly seen in syndromic craniosynostosis, allowing for gradual expansion of the bone while stretching the soft tissues over several weeks allowing greater volumetric expansion than conventional techniques. Posterior cranial vault distraction osteogenesis constitutes a more gradual remodeling modality, with infrequent complications. As a first step in intracranial expansion, it preserves the frontal cranium for future frontofacial procedures. A drawback is the need for a second surgery to remove the device, and this must be taken into account during counseling.

Craniosynostosis: Monobloc Distraction with Internal Device and Its Variant for Infants with Severe Syndromic Craniosynostosis

The introduction of distraction osteogenesis to frontofacial monobloc advancement has increased the safety of the procedure. One hundred forty-seven patients with syndromic craniosynostosis underwent frontofacial monobloc advancement using 4 internal distractors. Twenty-five were aged 18 months or less. Ten patients presented with a tracheostomy, 5 (50%) were decannulated after surgery, and 3 others (30%) required an additional intervention before decannulation. Six patients required the addition of a transfacial pin and external traction. Very early frontofacial monobloc with 4 internal distractors is a safe and effective treatment to protect the ophthalmic, neurologic, and respiratory functions in infants with severe syndromic craniosynostosis.

Is reverse frontal cranioplasty eligible for the correction of both the forehead deformities and the intracranial hypertension in craniosynostosis? Comparison of the preoperative and postoperative intracranial volumes

BACKGROUND

This study aimed to describe the surgical technique of reverse frontal cranioplasty (RFC), the aesthetical modification as well as the modification of intracranial volume (ICV) to assess its potential eligibility for the treatment of the intracranial hypertension (IH).

MATERIALS AND METHODS

A retrospective monocentric study included the patients with a history of craniosynostosis with a forehead deformity who underwent RFC. A subjective outcome questionnaire (SOQ) was conducted with each patient or their parent to determine their level of satisfaction after RFC. Pre- and postoperative computed tomography (CT) scans were analyzed and compared to investigate the ICV change and fronto-nasal angle.

RESULTS

Eleven patients were included in the study (6 female and 5 male) with a mean age of 10.9 years old (range 3-23 years) and an average follow-up of 4.5 years (1-11 years). All patients responded to the questionnaire with a high level of overall satisfaction (mean 9.1/10). The mean preoperative FNA was 134° ± 5° while the mean postoperative angle was 126.4° ± 6, corresponding to an average decrease of 7.6° (95% CI, 4.0-11.2°; p < 0.001). One patient with preoperative IH had a clinical recurrence during the follow-up. The ICV was significantly higher after the surgery (p < 0.0001), with an average increase of 3.2% (95% CI, 2.3-4.1%).

CONCLUSION

Reverse (RFC) is a useful technique for the correction of the frontal malformations related to craniosynostosis, such as a sloping forehead and/or a lack of the supraorbital projection. Regarding the limited gain of intracranial volume (ICV), it should not be used alone as primary cranial expansion surgery for craniosynostosis with intracranial hypertension (IH).

Postnatal Sagittal Craniosynostosis: A Novel Presentation and Considerations in Diagnosis and Management

ABSTRACT

Sagittal craniosynostosis results in scaphocephaly from abnormal fusion of the sagittal suture. Traditionally, craniosynostosis presents at birth and is diagnosed within the first year of life. We report a patient with development of sagittal craniosynostosis after birth, which we term postnatal sagittal craniosynostosis (PSC). This is a rare occurrence in which management considerations are critical but are not well discussed. A 3-year old boy presented with concerns of a metopic ridge. Work-up revealed metopic ridging and an open sagittal suture. The patient later developed signs of increased intracranial pressure (ICP) and repeat CT scan 14 months later identified a newly fused sagittal suture. The patient underwent open posterior cranial vault expansion, resulting in resolution of symptoms. PSC is a rare condition and should be considered in otherwise unexplained increases in ICP among pediatric patients. Open posterior cranial vault expansion represents a safe and effective method to treat this condition.

Spring-assisted posterior vault expansion-a single-centre experience of 200 cases

PURPOSE

Children affected by premature fusion of the cranial sutures due to craniosynostosis can present with raised intracranial pressure and (turri)brachycephalic head shapes that require surgical treatment. Spring-assisted posterior vault expansion (SA-PVE) is the surgical technique of choice at Great Ormond Street Hospital for Children (GOSH), London, UK. This study aims to report the SA-PVE clinical experience of GOSH to date.

METHODS

A retrospective review was carried out including all SA-PVE cases performed at GOSH between 2008 and 2020. Demographic and clinical data were recorded including genetic diagnosis, craniofacial surgical history, surgical indication and assessment, age at time of surgery (spring insertion and removal), operative time, in-patient stay, blood transfusion requirements, additional/secondary (cranio)facial procedures, and complications.

RESULTS

Between 2008 and 2020, 200 SA-PVEs were undertaken in 184 patients (61% male). The study population consisted of patients affected by syndromic (65%) and non-syndromic disorders. Concerns regarding raised intracranial pressure were the surgical driver in 75% of the cases, with the remainder operated for shape correction. Median age for SA-PVE was 19 months (range, 2-131). Average operative time for first SA-PVE was 150 min and 87 for spring removal. Median in-patient stay was 3 nights, and 88 patients received a mean of 204.4 ml of blood transfusion at time of spring insertion. A single SA-PVE sufficed in 156 patients (85%) to date (26 springs still in situ at time of this analysis); 16 patients underwent repeat SA-PVE, whilst 12 underwent rigid redo. A second SA-PVE was needed in significantly more cases when the first SA-PVE was performed before age 1 year. Complications occurred in 26 patients with a total of 32 events, including one death. Forty-one patients underwent fronto-orbital remodelling at spring removal and 22 required additional cranio(maxillo)facial procedures.

CONCLUSIONS

Spring-assisted posterior vault expansion is a safe, efficient, and effective procedure based on our 12-year experience. Those that are treated early in life might require a repeat SA-PVE. Long-term follow-up is recommended as some would require additional craniomaxillofacial correction later in life.

Extended experience in parieto-occipital expansion surgery by meander technique-clinical and radiological evaluation

INTRODUCTION

Brachycephaly and anterior and posterior plagiocephaly appear as an isolated entity or manifest in syndromic conditions. In severe cases, possible treatment options currently comprise either cranioplasty or osteogenetic distraction. The aim of this paper is to retrospectively review the perioperative course of a series of children treated by posterior meander expansion technique at our institution with focus on the course of postoperative intracranial volume and eventual tonsillar descent evolution.

METHODS

Forty-two children received a posterior cranial vault remodeling by means of a posterior meander technique during a 7-year period. Hospital records were reviewed, and pre- and postoperative MRIs were analyzed for intracranial volume, cephalic and asymmetry index, and tonsillar position over time.

RESULTS

Median age at surgery was 11.5 months (range 17 days-10 years). Nineteen children had a symmetrical cranial deformity, twenty-three an asymmetrical synostosis. Half of the cohort showed a syndromic condition. Transfusions were administered in the majority (92.2%) of the cases. A significant postoperative increase of intracranial volume was present from 1188.9 ± 370.4 cm³ to 1324.8 ± 352.9 cm³ (p < 0.001). The asymmetry index showed a significant improvement postoperatively: 0.86 ± 0.06 versus 0.91 ± 0.05 (p < 0.001), while the cephalic index showed a non-statistical change (0.91 ± 0.11 versus 0.88 ± 0.08). Tonsillar herniation, bilateral or homolateral, showed no significant changes at early control, while a nonsignificant amelioration of tonsillar descent was seen among children older than 12 months at late imaging follow-up.

CONCLUSION

Among the osteoplastic techniques, the posterior meander technique offers several advantages, such as early mobilization of the child, less bony defects, absence of implants, and a small complication rate. However, further comparative studies among different surgical techniques are needed.

Posterior Cranial Vault Distraction (PCVD): Common Complication Rates and Strategies of Prevention and Management

BACKGROUND

Posterior cranial vault distraction (PCVD) is a well-established procedure to treat infants with craniosynostosis. Craniofacial surgeons have seen an evolution in the complications following PCVD. This report aims to demonstrate the rates of common complications from PCVD, and to identify strategies for prevention and management of these complications.

METHODS

A formal literature review of studies on postoperative complications from PCVD was conducted to identify the breadth of reported complications from PCVD and rates of occurrence.

RESULTS

A total of 776 articles were captured by our search strategy. Nineteen original articles met inclusion criteria, with a total of 342 patients. The average rate of reported complications was 25%, range (0%-100%). The most commonly reported complication was postoperative infection (23.7%), followed by cerebrospinal fluid leak (20.3%) and device failure (15.3%). Postoperative infection, device exposure, iatrogenic vascular injury, cerebrospinal fluid leak, and other complications have the potential to disrupt distraction and increase morbidity and mortality.

CONCLUSIONS

By continuing to identify and evaluate complications, prevention strategies can be determined and standardized to decrease complications from PCVD. These efforts uphold the ultimate goal for surgeons involved in the treatment of craniosynostosis: to provide safe, effective surgical care.

Posterior calvarial distraction for complex craniosynostosis and cerebellar tonsillar herniation

OBJECTIVE

Children with syndromic, multisuture, and lambdoid craniosynostosis undergoing calvarial surgery often have Chiari malformation type I (CM-I) (or cerebellar tonsillar herniation). The optimal management of this patient group, including the surgical techniques and timing of surgery, remains uncertain. Posterior calvarial distraction (PCD) is an effective method to increase the supratentorial cranial volume and improve raised intracranial pressure in children with complex craniosynostosis. This study investigated the efficacy of PCD in posterior fossa (PF) volume expansion and treatment of CM-I and associated syringomyelia (syrinx) in this group of children.

METHODS

This retrospective study included patients who were surgically treated between 2006 and 2015. Over 10 years, 16 patients with multisuture synostosis, lambdoid synostosis, or craniosynostosis associated with a confirmed genetic syndrome, and a concurrent CM-I, were included. The mean age at the time of surgery was 5.1 years (range 8 months-18 years). Fourteen patients had pansynostosis and 2 had lambdoid synostosis. Eight had a confirmed syndromic diagnosis (Crouzon in 8, Apert in 4, Pfeiffer in 1, and Saethre-Chotzen in 1). Ten patients had raised intracranial pressure; 4 had syringomyelia.

RESULTS

The average clinical follow-up was 50 months (range 9-116 months). Clinically, 9 patients improved, 7 remained stable, and none deteriorated. The average distraction distance was 23 mm (range 16-28 mm). The PF anterior-posterior (AP) distance/width ratio increased from 0.73 to 0.80 mm (p = 0.0004). Although an osteotomy extending inferior to the torcula (compared with superior) was associated with a larger absolute PF AP distance increase (13 vs 6 mm, p = 0.028), such a difference was not demonstrable when the PF AP distance/width ratio was calculated. Overall, the mean tonsillar herniation improved from 9.3 to 6.0 mm (p = 0.011). Syrinx dimensions also improved in the AP (from 7.9 to 3.1 mm) and superior-inferior (from 203 to 136 mm) dimensions. No patients required further foramen magnum decompression for CM. Of the 16 patients, 2 had subsequent frontoorbital advancement and remodeling, of which 1 was for volume expansion and 1 was for cosmetic purposes. Two patients required CSF shunt insertion after PCD.

CONCLUSIONS

Following PCD, PF volume increased as well as supratentorial volume. This morphometric change was observed in osteotomies both inferior and superior to the torcula. The PF volume increase resulted in improvement of cerebellar tonsillar herniation and syrinx. PCD is an efficacious first-line, single-stage treatment for concurrent pansynostosis and lambdoid craniosynostosis, CM-I, and syrinx.

Cranial Fossa Volume and Morphology Development in Apert Syndrome

BACKGROUND

Apert syndrome causes normal or enlarged intracranial volume overall as patients grow. This study aimed to trace the segmental anterior, middle, and posterior cranial fossae volume and structural morphology in these patients, to help discern a more focused and individualized surgical treatment plan for patients with Apert syndrome.

METHODS

This study included 82 preoperative computed tomographic scans (Apert, n = 32; control, n = 50) divided into five age-related subgroups. The scans were measured using image processing and three-dimensional modeling software.

RESULTS

The middle cranial fossa volume was increased and was the earliest change noted. It was increased by 45 percent (p = 0.023) compared with controls before 6 months of age and remained increased into adulthood (161 percent, p = 0.016), with gradually increasing severity. The anterior and posterior cranial fossae volumes also increased, by 35 percent (p = 0.032) and 39 percent (p = 0.007), respectively. Increased depth of cranial fossae contributed most to the increase in volumes of patients with Apert syndrome, with correlation coefficients of 0.799, 0.908, and 0.888 for anterior, middle, and posterior cranial fossa, respectively. The intracranial volume was increased 12 percent (p = 0.098) across the entire test age range (0 to 26 years old), but only had statistical significance during the age range of 6 to 18 years (22 percent, p = 0.001).

CONCLUSIONS

Malformation of the middle cranial fossa is an early, perhaps the initial, pivotal cranial morphologic change in Apert syndrome. Increased cranial fossae depth is an inherent characteristic of the maldevelopment. Normalization of cranial volume and circumference overall may not achieve a normal skull structure, as it does not correct regional craniocerebral disproportion.

Ventricular shunt complications in patients undergoing posterior vault distraction osteogenesis

PURPOSE

The primary objective of this study is to investigate post-operative morbidity and shunt revision rates of patients with shunt-dependent hydrocephalus (SDH) undergoing posterior vault distraction osteogenesis (PVDO) compared to patients undergoing conventional posterior vault reconstruction (PVR).

METHODS

A retrospective case-controlled cohort analysis of all patients with SDH undergoing PVDO and PVR for syndromic or complex craniosynostosis was performed. Demographic information, perioperative variables, distraction protocols, and shunt-related complications-infection, surgical revision of shunt, increased length of stay (LOS), and readmission within 90 days of surgery-were compared using the appropriate statistical tests.

RESULTS

Fourteen patients with ventricular shunts who underwent PVDO and eight patients with shunts who underwent PVR were identified. Shunt-related complication rates were significantly higher with PVDO (n = 5) compared to PVR (n = 0), p = 0.0093. Among the five patients who suffered complications, the most common were shunt infection (n = 4), shunt malfunction (n = 4), and wound infections (n = 3). All patients with complications required additional operations for shunt revision and/or replacement; four patients required multiple takebacks for such procedures, with an average of three additional procedures per patient.

CONCLUSIONS

In complex or syndromic craniosynostosis patients who have previously undergone ventricular shunting, PVDO is associated with higher shunt-related complications and need for additional procedures when compared to traditional PVR. While the benefits of PVDO in the treatment of syndromic craniosynostosis are well documented, the risks of PVDO in the face of a VP shunt must be considered. Further investigation into patient-specific risk factors and risk reduction strategies is warranted.

A Craniometric Analysis of the Posterior Cranial Base After Posterior Vault Distraction

BACKGROUND

Posterior vault distraction osteogenesis (PVDO) has been demonstrated to effectively increase intracranial volume, treat increased intracranial pressure, and improve head shape in syndromic patients. The purpose of this study is to compare changes along the posterior cranial base before and after distraction.

METHODS

A retrospective review was completed of subjects who underwent PVDO with computed tomography scans at 2 time-points: within 3 months preoperatively and 1 to 6 months postoperatively. Using Mimics software, craniometric landmarks were identified and surface area of the foramen magnum was calculated. A comparison of pre- to postoperative measurements was completed using Wilcoxon matched-paired signed rank tests and linear regression.

RESULTS

A total of 65 PVDO subjects were identified, 12 subjects met inclusion criteria. Mean operative age was 3.0 ± 4.0 years. The cranial vault was distracted on average 25.0 ± 6.0 mm, with those < 12 months of age distracted 29.5 ± 4.9 mm and >12 months of age distracted 22.0 ± 4.9 mm (P = 0.0543). There was a significant increase in pre- to postoperative foramen magnum surface area (52.1 ± 63.2 mm, P = 0.002), length (0.9 ± 1.4 mm, P = 0.050), and width (0.6 ± 1.0 mm, P = 0.050). Similarly, linear distances between nasion and posterior cranial base landmarks such as foramen magnum (3.4 ± 4.2 mm, P = 0.010), and occipital protuberance (9.1 ± 9.6 mm, P = 0.003) were increased. Subjects under 12 months had a greater percentage increases in posterior vault length than those over 12 months.

CONCLUSION

Posterior vault distraction osteogenesis is associated with an increase in size of the foramen magnum, and lengthening of the posterior cranial base, both of which may be beneficial in patients with turribrachycephaly.

Quantification of Head Shape and Cranioplasty Outcomes: Six-compartment Volume Method Applied to Sagittal Synostosis

Supplemental Digital Content is available in the text.

Background:

Premature fusion of the sagittal (midline) suture between 2 parietal bones is the most common form of craniosynostosis. Surgical correction is mandated to improve head shape and to decrease the risk of raised intracranial pressure. This study evaluated the utility of 3-dimensional (3D) imaging to quantify the volumetric changes of surgical correction. Currently there is no standardized method used to quantify the outcomes of surgery for craniosynostosis, with the cranial index (width: length ratio) being commonly used.

Methods:

A method for quantification of head shape using 3D imaging is described in which the cranium is divided up into 6 compartments and the volumes of 6 compartments are quantified and analyzed. The method is size invariant, meaning that it can be used to assess the long-term postoperative outcomes of patients through growth. The method is applied to a cohort of sagittal synostosis patients and a normal cohort, and is used to follow up a smaller group of synostotic patients 1, 2, and 3 years postoperatively.

Results:

Statistical analysis of the results shows that the 6-compartment volume quantification method is more accurate in separating normal from synostotic patient head shapes than the cranial index.

Conclusions:

Spring-mediated cranioplasty does not return head shape back to normal, but results in significant improvements in the first year following surgery compared with the preoperative sagittal synostosis head shape. 3D imaging can be a valuable tool in assessing the volumetric changes due to surgery and growth in craniosynstosis patients.

Posterior Distraction First or Fronto-Orbital Advancement First for Severe Syndromic Craniosynostosis

PURPOSE

Posterior calvarial vault expansion using distraction osteogenesis is performed for syndromic craniosynostosis as the first choice. This procedure allows far greater intracranial volume than fronto-orbital advancement (FOA). This study aimed to determine the most suitable timing of posterior distraction or FOA to sufficiently increase the intracranial volume and remodel the skull shape.

PATIENTS AND METHODS

From 2014 to 2017, the authors performed posterior distraction in 13 patients with syndromic craniosynostosis. Data on premature suture fusion, age at first visit, age at surgery, skull thickness, and complications were collected.

RESULTS

Five patients underwent posterior distraction at approximately 12 months of age and had no complications, including cerebrospinal fluid leakage or gull wing deformity. However, during the waiting period for the operation, the skull deformity continues to extend upward (turribrachycephaly). To prevent progress of the skull deformity, the authors performed the operation at approximately 6 months of age in 7 patients. However, in 3 of 7 patients whose lambdoid sutures were opening, gull wing deformity occurred. From these results, in a patient with severe Beare-Stevenson syndrome, the authors performed FOA first at 5 months of age, followed by posterior distraction at 12 months of age, and achieved favorable results.

CONCLUSIONS

Treatment patterns are patient specific and should be tailored to premature suture fusion, specific skull deformity, and required intracranial volume of each patient.