The growth of the neurocranium: literature review and implications in cranial repair

Optimal Timing of Cranioplasty After Decompressive Craniectomy: Timing or Collapse Ratio

BACKGROUND AND OBJECTIVES

Although cranioplasty (CP) is a relatively straightforward surgical procedure, it is associated with a high complication rate. The optimal timing for this surgery remains undetermined. This study aimed to identify the most suitable timing for CP to minimize postoperative complications.

METHODS

We conducted a retrospective analysis of all CP cases performed in our department from August 2015 to March 2022. Data were gathered through case statistics and categorized based on the occurrence of complications. The collapse ratio was determined using 3-dimensional Slicer software.

RESULTS

In our retrospective study of 266 patients, 51 experienced postoperative complications, including hydrocephalus, epidural effusion, subdural hematoma, epilepsy, and subcutaneous infection. Logistic regression analysis identified independent predictors of postcranioplasty complications, and a nomogram was developed. The predictive value of the logistic regression model, collapse ratio, and decompression craniotomy-CP operation interval for post-skull repair complications was assessed using receiver operating characteristic curve analysis. No significant differences were observed in postoperative complications and decompression craniotomy-CP intervals between the groups (P = .07, P > .05). However, significant differences were noted in postoperative collapse ratios and CP complications between the groups (P = .023, P < .05). Logistic regression revealed that the collapse ratio (odds ratio = 1.486; 95% CI: 1.001-2.008; P = .01) and CP operation time (odds ratio = 1.017; 95% CI: 1.008-1.025, P < .001) were independent risk factors for postoperative complications. Receiver operating characteristic curve analysis indicated that the collapse ratio could predict CP postoperative complications, with a cutoff value of 0.274, an area under the curve of 0.621, a sensitivity of 62.75%, and a specificity of 63.26%.

CONCLUSION

The post-skull repair collapse ratio is a significant predictor of postoperative complications. It is advisable to base the timing of surgery on the extent of brain tissue collapse, rather than solely on the duration between cranial decompression and CP.

Decompressive craniotomy in split-technique (DCST) for TBI in infants: introducing a new surgical technique to prevent long-term complications

INTRODUCTION

Decompressive craniectomy (DC) is rarely required in infants. These youngest patients are vulnerable to blood loss, and cranial reconstruction can be challenging due to skull growth and bone flap resorption. On the other hand, infants have thin and flexible bone and osteogenic potential. MATERIAL AND METHODS: We propose a new technique called DCST, which makes use of these unique aspects by achieving decompression using the circumstance of the thin and flexible bone. We describe the surgical technique and the follow-up course over a period of 13 months.

RESULTS AND CONCLUSION

In our study, DCST achieved adequate decompression and no  further repeated surgeries in accordance with decompressive craniectomy were needed afterwards.

Endoscopic Strip Craniectomy and Helmet Therapy for Sagittal Craniosynostosis: An Analysis of Cranial Growth Changes in the Early Postoperative Period

OBJECTIVE

The purpose of this study is to analyze cranial width and length growth curves in the early postoperative period of patients by undergoing endoscopic sagittal strip craniectomy (ESC) to determine the timing of the maximal growth curve change. By analyzing the complex interplay of cephalic length and width measurements, we hope to better understand the cephalic index (CI) growth curve during this early period. This is the first of a multistep process to elucidate the ideal cranial remolding orthosis (CRO) treatment duration.

DESIGN

Retrospective review.

SETTING

Tertiary academic institution.

PATIENTS

Children with isolated sagittal craniosynostosis.

INTERVENTIONS

ESC and postoperative CRO treatment (2015-2019).

MAIN OUTCOME MEASURES

One cranial orthotist obtained preoperative and postoperative measurements. The maximal rate of change of width, length, and CI were compared against the postoperative week these occurred.

RESULTS

Thirteen children (mean age: 3.3 months, average preoperative CI: 73.4) underwent this intervention. CI reached its highest growth rate by 4.9 average weeks postoperatively, which correlated with the maximal width growth rate (5.2 weeks). Length curves reached their maximal growth rate by 15.5 weeks. CI peaked (81.3) by 22.7 weeks postoperatively, a significant increase from baseline.

CONCLUSIONS

Following ESC, in the early postoperative period, the CI growth curve has 4 phases: initial rapid expansion, early and late slowed expansion, and plateau, followed by possible regression phases. This highlights the importance of early postoperative CRO initiation, CRO compliance, and properly fitting CROs, especially in the first 2 phases. This data sets the stage for investigating the ideal treatment length.

Characterization of cranial growth patterns using craniometric parameters and best-fit logarithmic growth curves

Few studies have reported a complete quantitative database of cranial growth, from infancy to adulthood, as a reference through three-dimensional analysis. Our study aimed to characterize cranial growth patterns using craniometric parameters by establishing sex- and age-specific norms. In total, 1009 Korean patients (male-to-female ratio, 2:1; age range, 0-18 years) who underwent thin-slice computed tomography (CT) scans for head trauma were divided into 20 age groups, with a 6-month interval for those under 2 years and a 1-year interval for those over 2 years. After four reference planes [Frankfurt horizontal (FH), midsagittal, and two coronal planes passing the sella (S) and basion (B)] had been established, intracranial volume (ICV), anteroposterior diameter (APD), biparietal diameter (BPD), cranial heights (CHs), cephalic index (CI, BPD/APD), and height index (HI, CH-B/APD) were measured using Mimics software. Best-fit logarithmic curves were derived using a linear regression model. The best-fit curves for ICV (cm3) were y = 785.6 + 157*ln(age) for males (R2 = 0.5752) and y = 702 + 150.5*ln(age) for females (R2 = 0.6517). After adjustment for age, males had higher values of ICV, APD, BPD, and CHs than females (all p < 0.0001). ICV, APD, BPD, and CHs demonstrated a rapid increase during the first few months of life, reaching 90-95% of the adult size by 5-6 years of age, while CI and HI showed a continuous decline by 4%, regardless of sex. This study presented cranial growth references for more than 1000 of the Korean population aged up to 18 years. This might help to provide guidelines for diagnosis and treatment (including timing, amount, and direction) for cranial reconstruction in pediatric patients with craniosynostosis.

Chiari I malformation: management evolution and technical innovation

BACKGROUND AND DEFINITION

In recent years thanks to the growing use of radiological assessment, Chiari I malformation became one of the major diseases for a neurosurgeon to deal with. CIM can be classified according to the extent of cerebellar tonsil tip into the foramen magnum being a protrusion over five mm considered pathological. Such a disease is a heterogeneous condition with a multifactorial pathogenetic mechanism that can subdivided into a primary and secondary form. Regardless of the form, it seems that CIM is the result of an imbalance between the volume of the braincase and its content. Acquired CIMs are secondary to conditions causing intracranial hypertension or hypotension while the pathogenesis of primary forms is still controversial.

PATHOGENESIS AND TREATMENT

There are several theories in the literature but the most accepted one implies an overcrowding due to a small posterior cranial fossa. While asymptomatic CIM do not need treatment, symptomatic ones prompt for surgical management. Several techniques are proposed being the dilemma centered in the need for dural opening procedures and bony decompression ones.

CONCLUSION

Alongside the paper, the authors will address the novelty presented in the literature on management, diagnosis and pathogenesis in order to offer a better understanding of such a heterogeneous pathology.

Pre-Operative Ocular Findings and Long-Term Follow-Up in a Large Cohort of Non-Syndromic Unicoronal Craniosynostosis

(1) Background: Non-syndromic unicoronal craniosynostosis (UCS) is associated with a high prevalence of ocular anomalies. Currently, the etiology of this association remains obscure, however, it is presumed to be primarily attributed to their orbital malformations and/or secondary to craniofacial surgery. We assessed pre-operative ophthalmological examinations of non-syndromic UCS patients and compared them with their postoperative outcomes and long-term follow-up. (2) Methods: A retrospective case series was conducted on medical records of patients with non-syndromic UCS at Sophia Children's Hospital, Rotterdam. Ophthalmologic examinations were collected at different time periods: T1 (first visit), T2 (<1 year after cranioplasty), and T3 (long-term follow-up at last visit). The McNemar's test was used for statistical analysis. (3) Results: A total of 101 patients were included, for whom examinations were available at T1 and T3. Patients had a mean age of 2.8 years (±2.7) and 9.5 (±4.9) at T1 and T3, respectively. At T1, 52 patients (51.5%) were diagnosed with strabismus, and 61 patients (60.4%) at T3. Vertical strabismus increased significantly from 23 patients (22.8%) at T1 to 36 patients (35.6%) at T3 (p = 0.011). Followed by astigmatism, which increased significantly from 38 (37.6%) at T1 to 59 (58.4%) patients at T3 (p = 0.001). T1 was available in 20 patients prior to fronto-orbital advancement (FOA), therefore, a sub-analysis was conducted on these patients, which was followed shortly after FOA at T2. Prior to FOA, strabismus was present in 11 patients (55.0%) and in 12 patients (60.0%) at T2. After FOA, strabismus worsened in two patients. (4) Conclusions: This study showed the high prevalence of ocular anomalies in patients with non-syndromic UCS before and after cranioplasty and at long-term follow-up. The findings of this study show that ophthalmic and orthoptic examinations are an important part of the optimal treatment of patients with non-syndromic UCS.

Meticulous and Early Understanding of Congenital Cranial Defects Can Save Lives

BACKGROUND

Omitting the early closure of the cranial sutures in newly born children is not an uncommon practice. We describe the natural history of several unrelated children and adults from two unrelated families. These children were born with variable clinical manifestations: craniofacial asymmetry, ocular proptosis, floppiness, and progressive deceleration in cognitive development. None of these children underwent a cranial sutures assessment. False diagnoses of positional plagiocephaly, neonatal thyrotoxicosis, congenital muscular atrophy, and hydrocephalus were given to the parents. This sort of malpractice was the reason behind a sequence of devastating pathological events that occurred in the lifetime of these children and adults.

MATERIAL AND METHODS

This was a multigenerational study of two unrelated families. In total, we studied three children (aged 7-19 years) and three adults (aged 40-52 years) from two families. The children from the first family were referred to our departments because of pre-pubertal scoliosis, kyphoscoliosis, and early-onset osteoarthritis. Reading the clinical histories of these children signified apparent clinical misconceptions. For instance, craniofacial asymmetry was misinterpreted as positional plagiocephaly and treated by means of helmet molding therapy. Ocular proptosis was given the false diagnosis of neonatal thyrotoxicosis. Floppiness (hypotonia) was misdiagnosed as congenital muscular dystrophy. The index case from the second family showed progressive deceleration in his cognitive development, associated with signs of increased intracranial pressure. The only diagnosis was Dandy-Walker malformation. We documented every patient in accordance with the clinical and radiological phenotypic characterizations. The genotype characterization followed accordingly.

RESULTS

All patients in family (I) manifested a phenotype consistent to a certain extent with the clinical phenotype of Shprintzen-Goldberg syndrome (SGS), though the intensity of spine deformities was greater than has been described in the literature. The second family showed a constellation of Marfanoid habitus, craniosynostosis, increased intracranial pressure, hydrocephalus, Dandy-Walker malformation, seizures, and intellectual disability. The overall clinical phenotype was consistent but not fully diagnostic of craniosynostosis-Dandy-Walker-malformation hydrocephalus syndrome. The early closure of the sutures was totally different from one patient to another, including the premature closure of the metopic, coronal, squamosal, and sagittal sutures. One patient from family (II) underwent the implementation of a shunt system at the age of 3 years, unfortunately passing over the pre-existing craniosynostosis. In addition to skeletal deformities, a history of seizures and severe intellectual disability was recorded. The proband underwent chromosomal karyotyping, the FISH test, and whole-exome sequencing.

CONCLUSION

The purpose of this study was fivefold. Firstly, to gain a meticulous understanding in order to differentiate between positional plagiocephaly, hypotonia, and congenital exophthalmos and their connections to abnormal craniofacial contours was and still is our first and foremost concern. Secondly, we aimed to characterize craniosynostosis, seizures, intellectual disabilities, and hydrocephalus associated with Marfanoid habitus, which were clearly demonstrated in our patients. Thirdly, we aimed to address the imperative for interpretations of clinical and radiological phenotypes and relate these tools to etiological understanding, which is an essential basis for diagnosis in the majority of long-term pediatric admissions. Fourthly, we aimed to assess the impacts of the missed early closure by the pediatricians and pediatric neurologists, which added a heavy pathological burden on these patients and their families. Fifthly, we aimed to identify whether early and diligent recognition can assist in cranial vault remodeling via surgical intervention to halt premature cranial suture fusions and can possibly alter the devastating course and the complications of the synostosed sutures.

Early bone reformation after cranial vault remodelling for sagittal craniosynostosis: A retrospective 3D analysis

This study aims to measure postoperative bone reformation percentage, rates and patterns after cranial vault remodelling (CVR) in isolated non-syndromic sagittal craniosynostosis. Volumetric bone measurements were performed starting from the DICOM files of previously available postoperative CT scans. The 3D images were then resampled into the master box, and 'Skull 3D models' were derived. The percentage of bone reformation was investigated using automated 3D analysis software. The intra-rater reliability analysis revealed high reliability (Intraclass correlation coefficient = 0.99, p < 0.001). The median bone reformation volume and rate were 11.2 ml and 1.98 ml/week, respectively. The median percentage of bone reformation was 56.7% when the median postoperative CT timing was 6.1 weeks. As a statistic model, the linear plateau showed the highest Pseudo R² in both volume and percentage of bone reformation predicting patterns. By using the calculated model at 9 weeks postoperatively, the re-osteogenesis reaches 80% of the total cranial defect. After CVR, the early bone reformation pattern was demonstrated as a linear plateau model rather than logarithmic. This study gives a better understanding of the pattern and quantity of re-osteogenesis at cranial defects after CVR. The statistic model can facilitate healthcare practitioners to predict bone reformation and improve postoperative care protocol in sagittal craniosynostosis management.

Defining a Taxonomical Map for Craniosynostoses: An Integrated Nomenclature for Interdisciplinary Workflow and Problem Mapping in Craniosynostoses Management: A Feasibility Study

Craniosynostoses is a complex clinical and management challenge. This is further complicated by varying phenotypes and specific challenges. Most complex craniosynostoses are approached and managed the same way despite the clinical variability. The goals for craniofacial surgery are common, but the nomenclature based on phenotype, genotype, sutural involvement, or syndromic nature does not shed light on the management workflow. The descriptive diagnosis and terminologies do not highlight the priorities and the operational issues, and most specialists dealing with these conditions remain in their field of tunnelled vision. In this article, the authors propose a concept of categorization based on initial patient presentation. In addition, the etiology and the treatment status, if available, are incorporated along with the presentation. The utility of our proposed categorization is to create a goal-based universal language among various specialists involved.

Early diagnosis and surgical treatment of craniosynostoses

Craniosynostosis is a craniofacial anomaly, characterized by premature fusion of one or more of the cranial sutures. Each suture and their combination correspond to a special type of deformation.

Purpose. The study aimed at indicating the difficulties of early diagnostics of various forms of the craniosynostosis and evaluating the quality of treatment of patients with this disease depending on their age.

Material and methods. A survey of parents with craniosynostosis who were treated at the Almazov National Medical Research Centre in 2018–2019 was conducted. The parents of 107 patients were surveyed. The main objectives of our research were: to evaluate the timeliness of diagnosis of craniosynostosis at primary health care at patient’s place of residence; to compare the methods of diagnosis verification and to present the results of the parents’ subjective assessment of the results of surgical treatment at the early and long-term postoperative period.

Results. The median age of children when they were diagnosed with craniosystosis was 5 months, the median age of patients when they underwent a surgical treatment was 16 months. The median duration of the catamnesis was 6 months. We revealed that the preliminary diagnosis was established by a neurologist and pediatrician only in 21% of cases. Only at 28% of cases, children were directed to neurosurgeon, who confirm the diagnosis. In 38 (35.3%) cases, patient’s parents independently sought medical advice. The diagnosis was verified by the results of the computer tomography in 55% of patients. on because primary care specialists due to the lack of primary care specialists’ awareness about the diagnosis of craniosynostoses and attempts at long-term monitoring and conservative treatment. The timeliness of detection of craniosynostosis in the newborn period and in the|first month of life can significantly improve the cosmetic and functional outcomes of the disease. 

Poly (Butylene Succinate)/Silicon Nitride Nanocomposite with Optimized Physicochemical Properties, Biocompatibility, Degradability, and Osteogenesis for Cranial Bone Repair

Congenital disease, tumors, infections, and trauma are the main reasons for cranial bone defects. Herein, poly (butylene succinate) (PB)/silicon nitride (Si₃N₄) nanocomposites (PSC) with Si3N4 content of 15 w% (PSC15) and 30 w% (PSC30) were fabricated for cranial bone repair. Compared with PB, the compressive strength, hydrophilicity, surface roughness, and protein absorption of nanocomposites were increased with the increase in Si₃N₄ content (from 15 w% to 30 w%). Furthermore, the cell adhesion, multiplication, and osteoblastic differentiation on PSC were significantly enhanced with the Si₃N₄ content increasing in vitro. PSC30 exhibited optimized physicochemical properties (compressive strength, surface roughness, hydrophilicity, and protein adsorption) and cytocompatibility. The m-CT and histological results displayed that the new bone formation for SPC30 obviously increased compared with PB, and PSC30 displayed proper degradability (75.3 w% at 12 weeks) and was gradually replaced by new bone tissue in vivo. The addition of Si₃N₄ into PB not only optimized the surface performances of PSC but also improved the degradability of PSC, which led to the release of Si ions and a weak alkaline environment that significantly promoted cell response and tissue regeneration. In short, the enhancements of cellular responses and bone regeneration of PSC30 were attributed to the synergism of the optimized surface performances and slow release of Si ion, and PSC30 were better than PB. Accordingly, PSC30, with good biocompatibility and degradability, displayed a promising and huge potential for cranial bone construction.

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.

A semi-automatic three-dimensional technique using a regionalized facial template enables facial growth assessment in healthy children from 1.5 to 5.0 years of age

Objectives

To develop a semi-automatic technique to evaluate normative facial growth in healthy children between the age of 1.5 and 5.0 years using three-dimensional stereophotogrammetric images.

Materials and Methods

Three-dimensional facial images of healthy children at 1.5, 2.0, 2.5, 3.0, 4.0 and 5.0 years of age were collected and positioned based on a reference frame. A general face template was used to extract the face and its separate regions from the full stereophotogrammetric image. Furthermore, this template was used to create a uniform distributed mesh, which could be directly compared to other meshes. Average faces were created for each age group and mean growth was determined between consecutive groups for the full face and its separate regions. Finally, the results were tested for intra- and inter-operator performance.

Results

The highest growth velocity was present in the first period between 1.5 and 2.0 years of age with an average of 1.50 mm (±0.54 mm) per six months. After 2.0 years, facial growth velocity declined to only a third at the age of 5.0 years. Intra- and inter-operator variability was small and not significant.

Conclusions

The results show that this technique can be used for objective clinical evaluation of facial growth. Example normative facial averages and the corresponding facial growth between the age 1.5 and 5.0 years are shown.

Clinical Relevance

This technique can be used to collect and process facial data for objective clinical evaluation of facial growth in the individual patient. Furthermore, these data can be used as normative data in future comparative studies.

A Multicentric European Clinical Study on Custom-Made Porous Hydroxyapatite Cranioplasty in a Pediatric Population

Background

Cranioplasty (CP) is a surgical intervention aiming to re-establish the integrity of skull defects. Autologous bone and different heterologous materials are used for this purpose, with various reported related complications, especially in children.This study aims to evaluate the rate of complication in a multicentric cohort of pediatric patients treated by porous hydroxyapatite (PHA) CP implantation and to assess the reliability of post-marketing clinical data collected by a manufacturing company.

Methods

The authors proactively collected clinical data from 20 institutions in different European countries for patients under the age of 16 treated with a PHA implant. The data were obtained by conducting an on-site interview with physicians in charge of the patients (Post-Marketing Surveillance, PMS group). The endpoints were the incidence of adverse events and related implant removal. The clinical data were compared to the company-based register including all patients under the age of 16 who received the same implant from January 1, 2004 to December 31, 2020, and the collecting complications voluntarily reported by surgeons (Database, DB group).

Results

The two groups were similar in terms of demographic characteristics and rate of complications. In the PMS group, a total of 11 (16.9%) complications were reported in the group of 65 patients that were proactively collected. Both fractures and infections were the most common complications with 4 cases each (6.2%). In the case of both infections and fractures, revision surgery was required for only one patient (1.5%). Three (4.5%) cases of displacements were reported, and in one (1.5%) case, a surgical revision was required, for a total of 3 (4.5%) cases requiring surgical revision. The average follow-up was 26.7 months.

Conclusions

Different from a previous study on adult age, pediatric neurosurgeons are more prone to report even to the manufacturing company complications related to skull reconstruction in children. Therefore, these data can be compared with those of other clinical studies. The PHA CP in this series of 65 patients presents a complication rate collected on-site that is similar to other heterologous materials.

Prevalence of Postoperative Complications of Autologous and Heterologous Cranioplasty in the Pediatric Population: A Systematic Review of the Literature

INTRODUCTION

Cranial reconstruction (CR) is a neurosurgical procedure performed to restore the cranial vault after a decompressive craniectomy. There are contrasting reports from the literature about the complications related to the use of heterologous materials for CR in the pediatric population. In this study, the authors try to better define such a rate of adverse events for autologous and heterologous materials.

MATERIALS AND METHODS

A systematic review of articles published up to December 2021 was performed. Studies were included if they reported the specific use of cranioplasty materials following craniectomy in patients younger than 18 years of age and had a minimum follow-up of at least 1 year.

RESULTS

A total of 20 studies were selected. A total of 544 cases were included, of which 422 (77.6%) were with heterologous materials and 122 (22.4%) with autologous bone. The mean average age was 9.5 years. Polyetheretherketone and polymethylmethacrylate reported 29% and 33.3%, respectively, of complications, but only 3% and 5.6% of surgical revision. PHA reported a rate of 11.9%. Titanium reported 9.2% of complications and 4.1% of surgical revisions. Porous polyethylene had a complication rate of 36.4% and a revision rate of 0%.

CONCLUSION

There is still no perfect material for CR. It seems that heterologous materials are superior to autologous bone for CR in children, and we may consider, whenever economic conditions will allow it, to use alloplastic material as first-line in small children.

Protocol for the multicentre prospective paediatric craniectomy and cranioplasty registry (pedCCR) under the auspices of the European Society for Paediatric Neurosurgery (ESPN)

PURPOSE

In the paediatric age group, the overall degree of evidence regarding decompressive craniectomy (DC) and cranioplasty is low, whereas in adults, randomised controlled trials and prospective multicentre registries are available. To improve the evidence-based treatment of children, a consensus was reached to establish a prospective registry under the auspices of the European Society for Pediatric Neurosurgery (ESPN).

METHODS

This international multicentre prospective registry is aimed at collecting information on the indication, timing, technique and outcome of DC and cranioplasty in children. The registry will enrol patients ≤ 16 years of age at the time of surgery, irrespective of the underlying medical condition. The study design comprises four obligatory entry points as a core dataset, with an unlimited number of further follow-up entry points to allow documentation until adolescence or adulthood. Study centres should commit to complete data entry and long-term follow-up.

RESULTS

Data collection will be performed via a web-based portal (homepage: www.pedccr.com ) in a central anonymised database after local ethics board approval. An ESPN steering committee will monitor the project's progress, coordinate analyses of data and presentation of results at conferences and in publications on behalf of the study group.

CONCLUSION

The registry aims to define predictors for optimal medical care and patient-centred treatment outcomes. The ultimate goal of the registry is to generate results that are so relevant to be directly transferred into clinical practice to enhance treatment protocols.

Real-World Preliminary Experience With Responsive Neurostimulation in Pediatric Epilepsy: A Multicenter Retrospective Observational Study

BACKGROUND

Despite the well-documented utility of responsive neurostimulation (RNS, NeuroPace) in adult epilepsy patients, literature on the use of RNS in children is limited.

OBJECTIVE

To determine the real-world efficacy and safety of RNS in pediatric epilepsy patients.

METHODS

Patients with childhood-onset drug-resistant epilepsy treated with RNS were retrospectively identified at 5 pediatric centers. Reduction of disabling seizures and complications were evaluated for children (<18 yr) and young adults (>18 yr) and compared with prior literature pertaining to adult patients.

RESULTS

Of 35 patients identified, 17 were <18 yr at the time of RNS implantation, including a 3-yr-old patient. Four patients (11%) had concurrent resection. Three complications, requiring additional surgical interventions, were noted in young adults (2 infections [6%] and 1 lead fracture [3%]). No complications were noted in children. Among the 32 patients with continued therapy, 2 (6%) achieved seizure freedom, 4 (13%) achieved ≥90% seizure reduction, 13 (41%) had ≥50% reduction, 8 (25%) had <50% reduction, and 5 (16%) experienced no improvement. The average follow-up duration was 1.7 yr (median 1.8 yr, range 0.3-4.8 yr). There was no statistically significant difference for seizure reduction and complications between children and young adults in our cohort or between our cohort and the adult literature.

CONCLUSION

These preliminary data suggest that RNS is well tolerated and an effective off-label surgical treatment of drug-resistant epilepsy in carefully selected pediatric patients as young as 3 yr of age. Data regarding long-term efficacy and safety in children will be critical to optimize patient selection.

Sex Differences in the Temporalis Tendon-Aponeurotic Complex: An in vivo MRI Macroscopic Analysis in Children and Adolescents

The tendon-aponeurosis complex (TAC) of the temporalis dissipates forces produced during function. Abnormally reduced temporalis TACs have been found in individuals with chronic muscular temporomandibular disorders - a painful musculoskeletal condition that is more frequent in women than men. Whether there are sex differences in the temporalis TAC in healthy individuals is currently unknown. Here, we characterized and measured the temporalis TAC in healthy male and female young individuals between 5 and 15 years old to determine whether the volume of the temporalis TAC and the TAC-to-muscle ratio are different between males and females. We collected MRI studies from 90 healthy individuals, including equal numbers (15 M and 15 F) of young children (ages 5-7), children (9-11), and adolescents (13-15) and segmented the right temporalis and its TAC using software. Using general linear models, we tested the effect of sex, age, and their interaction on the volumes of the temporalis and its TAC, and the TAC-to-muscle ratio. The volumes of the temporalis and its TAC increased with age (both p < 0.001) and were not affected by sex (p = 0.252 and p = 0.179) or by the interaction sex-by-age (p = 0.079 and p = 0.095, respectively). The TAC-to-muscle ratio did not change significantly with age (p = 0.655) and was not affected by sex (0.438) or by the interaction sex-by-age (0.524). We provide, for the first time, volumetric data of the temporalis TAC in children and adolescents. The volumes of the temporalis TAC and the TAC-to-muscle ratio are not different between male and female individuals until the age of 15.

Postoperative helmet therapy following fronto-orbital advancement and cranial vault remodeling in patients with unilateral coronal synostosis

Out of all the synostotic corrective surgeries, fronto-orbital advancement and cranial vault remodeling for patients with unilateral coronal synostosis is one of the hardest to maintain symmetric and proportional correction without some amount of relapse. Over the course of 20 years operating on these patients, the senior author has made multiple adjustments to compensate for relapse asymmetry, including overcorrection on the affected side, increased points of fixation, periosteal release, and scalp expansion with galeal scoring to minimize tension of the closure. As a result of these interventions, we have seen improved immediate results following surgery. However, we have continued to note clinically significant relapse postoperatively. As such, we have started to implement postoperative helmet therapy (PHT) to help maintain the surgical correction, improve secondary brachycephaly, and increase overall symmetry. PHT is a reasonable low-risk complement to fronto-orbital advancement and cranial vault remolding. Clinically, PHT appears to help minimize relapse and improve overall head symmetry. Further investigation and increased patient enrollment are required to determine the true benefits of PHT in this patient population.

Three-pillar expansive craniotomy: a new surgical technique for cerebral decompression in children

PURPOSE

The aim of this study is to conduct a retrospective review of data obtained in all consecutive patients who had undergone cerebral decompression using the 3-pillar expansive craniotomy (3PEC) in our hospital between 2016 and 2020.

METHODS AND RESULTS

We developed a novel craniotomy technique using expansion cranioplasty in patients with traumatic brain injury or stroke, which could relieve intracranial hypertension, maintain cerebral protection, and avoid subsequent cranial repair. Sixteen patients aged 2-18 years old underwent the 3PEC. Two patients, who presented very severe neurological conditions at the admission, died. All surviving patients showed good neurological outcome. None of the survived patients presented with bone flap resorption or sinking flap syndrome.

CONCLUSION

The role of decompressive craniectomy has been recently questioned in the pediatric population by the use of decompressive craniotomy. In this limited study of children patients experiencing stroke or traumatic brain injury, 3PEC was proved useful in reducing intracranial pressure (ICP), thus, questioning the role of decompressive craniectomy in children. The technique effectively reduces postoperative complications and eliminates subsequent cranioplasty procedures otherwise introduced by traditional decompressive craniectomy.

Safety of responsive neurostimulation in pediatric patients with medically refractory epilepsy

OBJECTIVE

Approximately 75% of pediatric patients who suffer from epilepsy are successfully treated with antiepileptic drugs, while the disease is drug resistant in the remaining patients, who continue to have seizures. Patients with drug-resistant epilepsy (DRE) may have options to undergo invasive treatment such as resection, laser ablation of the epileptogenic focus, or vagus nerve stimulation. To date, treatment with responsive neurostimulation (RNS) has not been sufficiently studied in the pediatric population because the FDA has not approved the RNS device for patients younger than 18 years of age. Here, the authors sought to investigate the safety of RNS in pediatric patients.

METHODS

The authors performed a retrospective single-center study of consecutive patients with DRE who had undergone RNS system implantation from September 2015 to December 2019. Patients were followed up postoperatively to evaluate seizure freedom and complications.

RESULTS

Of the 27 patients studied, 3 developed infections and were treated with antibiotics. Of these 3 patients, one required partial removal and salvaging of a functioning system, and one required complete removal of the RNS device. No other complications, such as intracranial hemorrhage, stroke, or device malfunction, were seen. The average follow-up period was 22 months. All patients showed improvement in seizure frequency.

CONCLUSIONS

The authors demonstrated the safety and efficacy of RNS in pediatric patients, with infections being the main complication.

ABBREVIATIONS

DBS = deep brain stimulation; DRE = drug-resistant epilepsy; MDC = multidisciplinary conference; MER = microelectrode recording; MSHS = Mount Sinai Health System; RNS = responsive neurostimulation; SEEG = stereo-EEG; VNS = vagus nerve stimulation.

Barrel Stave Osteotomy Decompression for Acute Brain Injury in Infants: Technical Note

Decompressive craniectomy (DC) is rarely required in infants, but when performed several aspects should be considered: These youngest patients are vulnerable to blood loss and cranial reconstruction can be challenging due to skull growth and bone flap resorption. On the other hand, infants have thin and flexible bone and osteogenic potential. The authors propose a technique which makes use of these unique aspects by achieving decompression with the craniofacial method of barrel stave osteotomy, aiming to achieve adequate DC, limit perioperative risks and facilitate subsequent cranial reconstruction.

Hydroxyapatite ceramic implants for cranioplasty in children: a retrospective evaluation of clinical outcome and osteointegration

INTRODUCTION

Cranioplasty in children is a controversial and challenging issue, since there is still no consensus on the ideal material. Main problems in paediatric age are represented by the child's growing skull, the lower bone thickness and the high incidence of cerebrospinal fluid (CSF) disorders or brain swelling. Autologous bone is still considered the "gold standard". When it is not available, a wide range of alloplastic materials have been proposed. Hydroxyapatite, a ceramic-based derivative, bears a chemical composition very similar to the human natural bone, making this material a valuable alternative to other cranioplasty solutions.

METHODS

All patients implanted with a custom-made porous hydroxyapatite device at Santobono-Pausilipon Hospital in Naples were retrospectively reviewed. A follow-up CT scan of the skull was performed from 1 up to 48 months postoperatively to document the bone ingrowth as well as the osteointegration process. The bone density was measured as according to the Hounsfield scale at the bone-implant interface.

RESULTS

Between 2014 and 2018, 11 patients (7 males, 4 females) underwent cranioplasty with hydroxyapatite ceramic implants (HAP). Patients' age ranged between 3 and 16 years old. Initial aetiology was trauma in most cases. Two subjects were implanted with HAP as primary cranioplasty, 9 as revision surgery following previous cranioplasty failure. Sites of the cranial defect were unilateral fronto-temporo-parietal (N = 8), unilateral frontal (N = 1) and bifrontal (N = 2). Two patients with large bilateral defects received two prostheses. In one of these, the two prostheses were explanted and replaced with two back-up implants (accounting for a total of 15 implants in 11 patients). Osteointegration was measurable for 12 out of 15 implanted devices. The mean percentage was about 51%. There were six asymptomatic prosthesis fractures (40%), all occurring within 6 months from implant. In one case, the bifrontal prostheses were explanted and replaced. This was the only patient who underwent revision surgery.

CONCLUSION

Hydroxyapatite ceramic implants represent a valid alternative to other cranioplasty solutions. Where coaptation occurs correctly, with good osteointegration, implant mechanical resistance increases over time.