Evaluation of postoperative fluctuations in plasma sodium concentration and triphasic response after pediatric craniopharyngioma resection: A French cohort study.

INTRODUCTION: Disturbances in plasma sodium levels are a major complication following recent resections of craniopharyngiomas in children. They must be properly managed to avoid neurological sequelae. We aimed to describe the variations and characteristics of postoperative natremia in children who had undergone a first craniopharyngioma resection with a particular focus on the frequency of triphasic syndrome in these patients. METHODS: Paediatric patients with craniopharyngiomas who underwent a first surgical resection in the neurosurgery department of the Hôpital Femme Mère Enfant (Lyon, France) between January 2010 and September 2021 were included in the present study and the medical records were analysed retrospectively. RESULTS: A total of 26 patients were included. Of these, 17 (65.4%) had a postoperative course characterised by the occurrence of both initial diabetes insipidus (DI) and hyponatremia a few days later. Eight patients (30.8%) presented then with isolated and persistent DI. Patients with the triphasic syndrome had a significantly higher grade of Puget classification on MRI (1 and 2), compared to the other patients. CONCLUSION: Dysnatremia is common after craniopharyngioma resections in children. This immediate postoperative complication is particularly difficult to manage and requires rapid diagnosis and prompt initiation of medical treatment to minimize fluctuations in sodium levels and avoid neurological sequelae.

Role of sodium fluorescein in pediatric low-grade glioma surgery: an update.

PURPOSE: Complete surgical resection is still the mainstay in the treatment of central nervous system low-grade tumors, eventually resulting curative. The complete surgical removal of these lesions, however, may be difficult in some cases because of their infiltrative nature. Intraoperative adjuncts may be a game changer. Sodium fluorescein (SF) is among the ideal candidates as intraoperative tools to favor the actual recognition of the tumor extension, since it accumulates in areas of altered blood-brain barrier, a typical characteristic of pediatric gliomas, and has a low rate of adverse events. This work proposes an update of previous works about the evaluation of the feasibility and usefulness of a systematic use of SF in a low-grade lesion group of pediatric patients. METHODS: Pediatric patients operated on for a resection or a biopsy of a low-grade glial or glioneuronal lesion (WHO grade I and II) at our Institution between September 2021 and December 2023, with the intraoperative use of sodium fluorescein (SF), were enrolled in the study. We collected pre-operative and postoperative clinical and radiological data, intraoperative findings, and post-operative pathological diagnoses. RESULTS: No adverse events were registered related to the intraoperative use of SF. SF appeared useful for the localization of boundaries of tumors, especially when characterized by a high degree of infiltration or by a deep-seated location, and for the checking of possible tumor remnants at the end of surgery. A good tumor-to-healthy tissue contrast was registered when tumor visualization was in a range between 1 to 2 h and 30 min after SF injection. Possible "false positives" due to intraoperative vascular wall injury and clearance of SF from both tumor and healthy tissue were observed in some cases and still remain open issues. CONCLUSIONS: SF is a feasible and safe intraoperative adjunct tool in the surgical removal of pediatric low-grade tumors. SF may show its usefulness especially in selected cases, such as deep-seated lesions and infiltrating tumors. Its safety profile, user-friendly management, and potential utility in both tumor resections and neuronavigated biopsies favor its wider use in the surgical treatment of pediatric low-grade tumors.

Preoperative 11 C-Methionine PET-MRI in Pediatric Infratentorial Tumors.

PURPOSE: MRI is the main imaging modality for pediatric brain tumors, but amino acid PET can provide additional information. Simultaneous PET-MRI acquisition allows to fully assess the tumor and lower the radiation exposure. Although symptomatic posterior fossa tumors are typically resected, the patient management is evolving and will benefit from an improved preoperative tumor characterization. We aimed to explore, in children with newly diagnosed posterior fossa tumor, the complementarity of the information provided by amino acid PET and MRI parameters and the correlation to histopathological results. PATIENTS AND METHODS: Children with a newly diagnosed posterior fossa tumor prospectively underwent a preoperative 11 C-methionine (MET) PET-MRI. Images were assessed visually and semiquantitatively. Using correlation, minimum apparent diffusion coefficient (ADC min ) and contrast enhancement were compared with MET SUV max . The diameter of the enhancing lesions was compared with metabolic tumoral volume. Lesions were classified according to the 2021 World Health Organization (WHO) classification. RESULTS: Ten children were included 4 pilocytic astrocytomas, 2 medulloblastomas, 1 ganglioglioma, 1 central nervous system embryonal tumor, and 1 schwannoma. All lesions showed visually increased MET uptake. A negative moderate correlation was found between ADC min and SUV max values ( r = -0.39). Mean SUV max was 3.8 (range, 3.3-4.2) in WHO grade 4 versus 2.5 (range, 1.7-3.0) in WHO grade 1 lesions. A positive moderate correlation was found between metabolic tumoral volume and diameter values ( r = 0.34). There was no correlation between SUV max and contrast enhancement intensity ( r = -0.15). CONCLUSIONS: Preoperative 11 C-MET PET and MRI could provide complementary information to characterize pediatric infratentorial tumors.

Brainstem tumors in children: a monocentric series in the light of genetic and bio-molecular progress in pediatric neuro-oncology.

Introduction: Brainstem tumors represent a challenge. Their management and prognosis vary according to anatomopathological findings and genetic and bio-molecular fingerprints. We present our experience with pediatric brainstem tumors. Material and methods: All patients admitted for a brainstem tumor at the Pediatric Neurosurgical Unit at Hôpital Femme Mère Enfant hospital between January 1997 and December 2019 were considered. Patients data were obtained through a retrospective review of the medical records; follow-up was from the last outpatient consultation. Results: One hundred and twelve patients were included. Eighty-five patients (75.9%) had open surgery or stereotactic biopsy. Thirty-five patients were treated for hydrocephalus. Sixty-six received an adjuvant treatment. Several protocols were adopted according to the SFOP and SIOP during this time period. The overall survival rate was 45% with a median follow-up of five years (range 1-18 year). However, the survival rate was very different between the diffuse intrinsic pontine gliomas (DIPG) and the others tumor types. If we exclude the DIPG (59 patients), of which only 1 was alive at 3 years, the survival rate was 90.6% (only 5 deaths over 53 patients) with a median follow up of 5 years. Conclusions: Our series confirms that benign tumors of the brainstem have a good survival when treated with surgical removal ± adjuvant therapy. Diffuse pontine gliomas continue to have a dismal prognosis. Individualized treatment based on molecular fingerprints may help to select the best adjuvant therapy and hence potentially improve survival.

Pineal cysts in children: a paediatric series treated over the last twenty years in Lyon.

BACKGROUND: Pineal cysts are a rare lesion of the pineal gland. Pineal cysts are benign lesions, generally asymptomatic, and are usually an incidental discovery on MRI performed for other problems. The management of pineal cysts in children remains a matter for debate. Here, we report our own retrospective paediatric cases that have been surgically treated and review the paediatric literature on this topic. METHODS: This is a retrospective monocentric study. All patients operated by the senior author (CM) for a benign pineal cyst from 2000 to 2021 were included. All other pineal region cystic lesions were excluded. Medical and surgical data were extracted from the hospital medical database. RESULTS: Twelve patients were included. The clinical symptomatology was characterized by headaches in seven patients, visual troubles in two patients, precocious puberty in one patient, signs of intracranial hypertension in two patients, seizures associated with headache in one patient, and headaches associated with behavioural troubles in another patient. No major post-operative complications were observed in this series. It is to noted that surgery was performed because a suspicion of a true pineal parenchymal tumour has been made. Histopathological study came back with the diagnosis of pineal cyst. CONCLUSIONS: Pineal cyst is rare. If the radiological diagnosis is clear, no surgery is advocated except in cases associated with hydrocephalus and rapid growth. In case of a suspicion of a true pineal parenchymal tumour, a surgery may be needed to confirm the diagnosis. Lastly, we stress that only cystic lesions of the pineal gland itself should be considered as pineal cyst.

The sub-occipital transtentorial approach for pineal region tumors: how I do it.

BACKGROUND: Two major approaches exist for the surgical removal of pineal region tumors: the supracebellar infratentorial and the sub-occipital transtentorial. METHODS: We present the Lyon's technique of the sub-occipital transtentorial approach for pineal region tumors and our tricks to avoid complications. The principle is to expose the pineal region under the occipital lobe and not through the interhemispheric fissure. CONCLUSIONS: The sub-occipital transtentorial approach is a direct, extra cerebral, safe, and effective way to access tumors of the pineal region.

Clinical interest of molecular study in cases of isolated midline craniosynostosis.

In some cases of infants with apparently isolated single-suture synostosis, an underlying variant can be found. We aimed to determine the molecular substratum in isolated sagittal and metopic craniosynostosis. To this end, we included all infants who presented isolated midline synostosis (sagittal or metopic) and had undergone surgery at the craniosynostosis national reference center of Lyon University Hospital. All infants were examined by a multidisciplinary team including neurosurgeons, clinical geneticists and neuropsychologist. Among 101 infants tested, 13 carried a total of 13 variants; that is, 12.9% of the infants carried a variant in genes known to be involved in craniosynostosis. Seven infants carried SMAD6 variants, 2 in FGFR2, 1 in TWIST1, one in FREM1, one in ALX4 and one in TCF12. All variants were detected at the heterozygous level in genes associated with autosomal dominant craniosynostosis. Also, neurodevelopmental testing showed especially delayed acquisition of language in children with than without variants in SMAD6. In conclusion, a high percentage of young children with isolated midline craniosynostosis, especially in isolated trigonocephaly, carried SMAD6 variants. The interpretation of the pathogenicity of the genes must take into account incomplete penetrance, usually observed in craniosynostosis. Our results highlight the interest of molecular analysis in the context of isolated sagittal and/or metopic craniosynostosis to enhance an understanding of the pathophysiology of midline craniosynostosis.

Surgical management of Chiari malformation type 1 associated to MCAP syndrome and study of cerebellar and adjacent tissues for PIK3CA mosaicism.

BACKGROUND: Subjects with Megalencephaly-Capillary Malformation-Polymicrogyria syndrome (MCAP) can present with a Chiari Malformation Type 1 and resulting alterations in cerebrospinal fluid (CSF) dynamics, which may require surgical treatment. The aim of this paper is to describe the features of children with MCAP who underwent surgical decompression for CM1, and to explore the PIK3CA variant allele frequency (VAF) identified in cerebellar parenchyma and other adjacent structures. METHODS: This study reviewed two cases of children with CM1 and MCAP who underwent surgical decompression treatment. These two cases were part of a national cohort of 12 MCAP patients who had CM1, due to their surgical eligibility. Tissue samples were obtained from the cerebellar tonsils and adjacent anatomical structures during the surgical procedures. Samples were then subsequently analyzed for PIK3CA postzygotic variants. RESULTS: In both cases, alterations in CSF dynamics, specifically hydrocephalus and syringomyelia, were observed and required surgical treatment. PIK3CA targeted sequencing determined the VAF of the postzygotic variant in both cerebellar and adjacent bone/connective tissues. DISCUSSION: The recognition of a CM1 comorbidity in MCAP patients is of paramount importance when considering personalized treatment options, especially because these patients are at higher risk of developing complications during surgical decompression surgery. The variable PIK3CA VAF identified in the different analyzed tissues might help explain the heterogeneous nature and severity of anomalies observed in the volume of the posterior fossa structures in MCAP patients and associated CSF and venous disorders.

Sodium fluorescein in pediatric oncological neurosurgery: a pilot study on 50 children.

BACKGROUND: Sodium fluorescein (SF) is currently considered a valid intraoperative adjunct in the resection of high-grade brain lesions in adults. Experiences in pediatric groups and in low-grade gliomas and other low-grade lesions are still limited in literature, and subjective evaluation of fluorescence is still a limitation. MATERIAL AND METHODS: This study retrospectively reviewed all patients with brain or spine lesions operated on from September 2021 to July 2022 in the Pediatric Neurosurgery Unit of Hôpital Femme Mère Enfant, Lyon, who had received 5 mg/kg of 10%. Surgery was performed using a YELLOW560 filter at crucial times. At the end of surgery, the first operator completed a questionnaire, including his opinion on whether SF had been useful in tumor resection, recorded as a binary variable. Post hoc, surgical images were reviewed using ImageJ, an open-source Java image processing platform. In order to compare independent discrete variables, we applied the Student's t test, and we applied the Chi-square or Fisher exact test for binary variables. A threshold of p < 0.05 was set for statistical significance. RESULTS: We included 50 pediatric patients (0.2-17.6 years old). Forty/50 lesions showed SF uptake (80%). The differentiation between healthy and affected tissue, thanks to SF, subjectively evaluated by the surgeon, had as objective counterpart the statistically significant higher brightness of green in lesions, registered by the software (p < 0.001). SF overall allowed a good differentiation in 33/50 lesions, and overall utility of SF has been noted in 67% of them. When specifically considering gliomas, overall utility reached 75%. CONCLUSION: SF is a feasible, safe, and useful intraoperative adjunct in pediatric neurosurgery. In particular, it seems to have a promising role in some low-grade infiltrating glial tumors. The subjective evaluation of fluorescence seems to be reliable with respect to image analyses software.

Sodium fluorescein in pediatric neurosurgery: a systematic review with technical considerations and future perspectives.

BACKGROUND: Sodium fluorescein (SF) is routinely used in several centers as a valid intraoperative adjunct in adult oncological neurosurgery. Its use in pediatric neurosurgery is increasing, although its role is not yet well-defined in children. We reviewed the current literature in order to evaluate the use of SF in children with CNS and PNS lesions. METHODS: For this systematic review, we searched PubMed, Scopus, and Embase databases, and forward and backward citations for studies published between database inception and July 31st, 2022. We included any article type or congress abstract adding at least a new case, without restrictions of language or publication status, concerning the use of SF in neurosurgical procedures in patients under 18 years of age. We excluded studies concerning purely vascular cases and cerebrospinal fluid leaks. RESULTS: Of 4094 records identified, 19 articles were eligible and included for further analysis. As per July 31st, 2022, at least 119 patients aged from 11 months to 17.9 years underwent surgery with SF. No serious adverse events were reported. A large variety of tumor types was operated, in most cases resected under the specific YELLOW 560 nm filter after a low-dose SF injection (2-5 mg/kg) at the end of anesthesia induction. SF was reported particularly useful in gangliogliomas and pilocytic astrocytomas. DISCUSSION/CONCLUSION: Given its easy-to-use profile, low cost, and safety, SF seems to be a feasible and valid adjunct in the pediatric population when aiming at individuating a biopsy target or maximizing extent of resection, particularly in some tumor types. Further studies are required to strengthen the evidence on its impact on outcomes.

Results of the treatment of pineal tumors in children: the Lyon experience.

INTRODUCTION: Pineal tumors are rare and their incidence is of 1% among all pediatric tumors of the central nervous system. Patient survival depends on the histology, the extension of the surgical removal, and the efficacy of the complementary treatment (chemotherapy and cranio-spinal irradiation), as well as the age of the patient. MATERIALS AND METHODS: In this study, we analyzed 151 pediatric patients treated for pineal tumors from 1997 to 2020 in Lyon, France. All patients were recorded in the French Register of Pineal tumors, which has been centralized and maintained in Lyon since 2010. RESULTS: Our analysis shows that benign tumors have an overall positive prognosis with total surgical removal. Concerning pineal parenchymal tumors, pinealoblastomas have a poor prognosis , especially in children less than three years old. A new pathological classification system allows for a better stratification of patient risk within different groups of patients with pineal tumors. It is also important to note that the identification of DICER 1 syndrome in families with pinealoblastomas warrant further medical investigation. Patients with Germ Cell Tumors have more favorable outcomes, with a global survival rate of 87 % and a pure germinoma survival rate of almost 97%. When analyzing the prognosis of pineal gland gliomas, otherwise known as tectal plate gliomas, pilocytic astrocytomas had a promising prognosis. Otherwise, prognosis of other tectal plate gliomas are related to the grade of malignancy and the efficacy of complementary treatment. Lastly, papillary tumors need a complete removal for the best chance of survival, and Atypical teratoid/ rabdoid tumors (AT/TR) still have a bad prognosis, regardless of surgical resection. CONCLUSIONS: Our results show that, with regards to pediatric pineal region tumors, there are still areas in prognostic indicators that need to be improved. Similarly, these pathologies need to be treated via a multidisciplinary approach to improve a patient's survival rate and their quality of life.

Pediatric Low-Grade Glioma Surgery with Sodium Fluorescein: Efficient Localization for Removal and Association with Intraoperative Pathological Sampling.

Low-grade gliomas are among the most common CNS lesions in pediatrics and surgery is often the first-line treatment. Intraoperative tools have been developed to maximize the results of surgery, and in particular dyes such as sodium fluorescein (SF) have been investigated in high-grade adult lesions. The use of SF in pediatric low-grade gliomas is still unclear. We retrospectively reviewed 22 pediatric CNS low-grade gliomas operated on with SF from September 2021 to October 2022. A total of 86% of lesions showed SF uptake, which was helpful intraoperatively (confirmation of initial localization of the tumor, or identification of tumor remnants) in 74% of them. The intraoperative fluorescence seems associated with gadolinium enhancement at the preoperative MRI. Interestingly, the extemporaneous pathological sampling (EPS) was informative in every case showing SF uptake, whereas in cases without SF uptake, the EPS was non-informative, although the tissue was later confirmed as pathological. These findings highlight the interest of SF for perioperative diagnosis of tumor tissue and may suggest in which cases the differentiation of tumor-healthy tissue could be especially blurred, posing difficulties for the pathologist.

Non-accidental head injury of infants: legal implications for the pediatric neurosurgeon.

BACKGROUND: Though the neurosurgeon's role in non-accidental head injury (NAHT) is the prompt recognition and care of the inflicted injuries, he/she should be aware of the possible legal implications related to this particular neurosurgical condition. MATERIAL AND METHODS: Based on published data and their own clinical and medico-legal practice, the authors review the role of the neurosurgeon in NHAT. RESULTS: Besides the contribution that can be given by the neurosurgeon to a correct differential diagnosis, he/she is likely to be involved in the interpretations of the pathological findings in the case where the judge may request for a medical opinion concerning etiology, circumstances, severity, and consequences. As a member of a multidisciplinary team, usually the neurosurgeon is only requested for information regarding the lesions he was called to recognize and treat. Nevertheless, such information may have a pivotal part in the evaluation process. Consequently, the neurosurgeon should be able to reach a correct differential diagnosis of NAHT among all the events that may share similar clinical and anatomo-pathological characteristics and be aware of the ongoing scientific controversies related to the diagnosis and pathophysiology. CONCLUSIONS: In practical terms, the pediatric neurosurgeon is called to individuate and record all the precise details of the condition to be eventually offered to the judge in case of controversy. Whereas the diagnosis of NAHT should be evoked at the initial phase in order not to leave the child unprotected, all possible alternative hypotheses should be ruled out "beyond reasonable doubt" for the court. The medical file should be maintained in the record carefully and be accessible even after a long time.

Evaluation of the Perioperative and Postoperative Course of Surgery for Pineal Germinoma in the SIOP CNS GCT 96 Trial.

Background: CNS germinoma, being marker-negative, are mainly diagnosed by histological examination. These tumors predominantly appear in the suprasellar and/or pineal region. In contrast to the suprasellar region, where biopsy is the standard procedure in case of a suspected germ-cell tumor to avoid mutilation to the endocrine structures, pineal tumors are more accessible to primary resection. We evaluated the perioperative course of patients with pineal germinoma who were diagnosed by primary biopsy or resection in the SIOP CNS GCT 96 trial. Methods: Overall, 235 patients had germinoma, with pineal localization in 113. The relationship between initial symptoms, tumor size, and postoperative complications was analyzed. Results: Of 111 evaluable patients, initial symptoms were headache (n = 98), hydrocephalus (n = 93), double vision (n = 62), Parinaud syndrome (n = 57), and papilledema (n = 44). There was no significant relationship between tumor size and primary symptoms. A total of 57 patients underwent primary resection and 54 underwent biopsy. Postoperative complications were reported in 43.2% of patients after resection and in 11.4% after biopsy (p < 0.008). Biopsy was significantly more commonly performed on larger tumors (p= 0.002). Conclusions: These results support the practice of biopsy over resection for histological confirmation of pineal germinoma.

Recurrent Tethering in Conus Lipomas: A Late Complication Not to Be Ignored.

BACKGROUND: Recurrent symptomatic tethered cord (RTC) is a long-term complication of spinal cord lipomas, responsible for progressive motor deficits, urologic dysfunction, and aggravation of spinal deformities. We retrospectively analyzed all cases of recurrent tethering after spinal cord lipoma surgery, the clinical and radiologic features that led to the diagnosis, the surgical management, and the neuro-orthopedic outcome at the last follow-up. METHODS: The study was carried out over 20 years on 209 pediatric patients from a single institution, initially treated for a conus lipoma. RESULTS: Nine patients (4.8%) were surgically treated for an RTC. The age at retethering ranged from 2 to 12 years (median, 7.4 years). The time until the first and the second surgical procedure ranged from 19 to 140 months (median, 92 months [7.5 years]). The follow-up period after the second surgery ranged from 3 months to 13 years (median, 50 months). Regarding symptoms, pain responded well to surgery. Gait disturbances improved in 50% of patients after surgery. One patient with bladder dysfunctions also improved. The remaining patients maintained their presurgical status. CONCLUSIONS: When RTC is confirmed, the child should be referred to surgery as soon as possible, because we show that the postoperative clinical outcome improved and surgery did not worsen patients' condition. Follow-up should be as long as possible for these patients.

New insights in craniovertebral junction MR changes leading to stenosis in children with achondroplasia.

PURPOSE: To characterize natural history and early changes of craniovertebral junction stenosis in achondroplasia correlating with clinical and radiological outcome. METHODS: Retrospective measures on craniovertebral junction were performed blindly, on sagittal T2-weighted images, in 21 patients with achondroplasia referred from 2008 to 2020. Clinical and polysomnography data were retrospectively collected. Each patient was paired for age and gender with four controls. Wilcoxon means comparison or Student's t-tests were applied. RESULTS: Twenty-one patients (11 females, from 0.1 to 39 years of age) were analyzed and paired with 84 controls. A craniovertebral junction stenosis was found in 11/21 patients (52.4%), all before the age of 2 years. Despite a significant reduction of the foramen magnum diameter (mean ± SD: patients 13.6 ± 6.2 mm, controls 28.5 ± 4.7 mm, p < .001), craniovertebral junction stenosis resulted from the narrowing of C2 dens-opisthion antero-posterior diameter (8.7 ± 3.9 mm vs 24.6 ± 5.1 mm, p < .001). Other significant changes were opisthion anterior placement (-0.4 ± 2.8 mm vs 9.4 ± 2.3 mm, p < .001), posterior tilt of C2 (46.2 ± 13.7° vs 31.6 ± 7.9°, p < .001) and of C1 (15.1 ± 4.3° vs 11.9 ± 5.0°, p = 0.01), and dens thickening (9.4 ± 2.2 mm vs 8.5 ± 2.1 mm, p = 0.03), allowing to define three distinguishable early craniovertebral junction patterns in achondroplasia. All children with C2-opisthion antero-posterior diameter of more than 6 mm had a better clinical and radiological outcome. CONCLUSION: Craniovertebral junction in achondroplasia results from narrowing between C2 dens and opisthion related to anterior placement of opisthion, thickening of C2 dens, and posterior tilt of C1-C2. A threshold of 6 mm for dens-opisthion sagittal diameter seems to correlate with clinical and radiological outcome.

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.

Management of Chiari type I malformation: a retrospective analysis of a series of 91 children treated surgically.

INTRODUCTION: The diagnosis of Chiari I malformation, its symptomatology, and the results of its surgical management are still discussed. We report a pediatric series of CMI without associated skull base malformations or cerebellar growth anomalies operated between 2001 and 2018. MATERIAL AND METHODS: Ninety-one children out of 146 surgically treated cases have been included in the study. Age at surgery ranged from 5 months to 17 years clinical data, and complementary examinations leading to the surgical indication have been analyzed together with the surgical outcomes. The average follow-up duration was of 4 years. The occipito-cervical decompression with duraplasty without opening the arachnoid was the procedure of election. Three quarters of patients presented with headaches, 12% with cerebellar syndrome, 13% with vertigo, 26% with nausea or vomiting, 24% with sensorimotor deficits, 11% with cranial nerve deficits, and 29% with other symptoms. Eighteen percent of patients suffered from scoliosis, 47% had an associated syrinx and 16% a ventricular dilation. RESULTS: After the treatment, the clinical symptomatology improved in about three-quarters of the patients: headache (69.4%), nausea or vomiting (66.7%), sensorimotor deficits (55.6%), and other symptoms (78.3%). Syringomyelic cavities diminished partially in size or disappeared in 58.3% of patients, remained stable in 29.2%, and worsened in 12.5%. Only one-third of children with preoperative scoliosis benefited from the surgical treatment. No clinical signs or symptoms were found to be reliable predictors of surgical success, neither the extent of the cerebellar tonsil descent. CONCLUSION: Occipito-cervical decompression allows to improve the clinical condition in the majority of children with symptomatic CMI in the absence of associated cervico-spinal junction alterations, craniosynostosis, or cerebellar growth anomalies. No clinical signs or symptoms neither radiological criterion appear to be a specific finding for the surgical indication.

Fixed posterior cranial vault expansion technique.

BACKGROUND: Different techniques to reshape the posterior skull vault have been developed in the last decades, all sharing the same goals of increasing the skull volume, decreasing the intracranial pressure (ICP), correcting the cranial dysmorphy, and contributing to a better growth of the skull. Though over the last years most refinements in these techniques have focused on the use of hardware as distractors or springs, the fixed posterior vault expansion remains a valuable procedure for cranial remodeling. METHODS: We describe in details the technique used for fixed posterior vault expansion in children that is applied at the French Referral center for Craniosynostosis of Lyon, France. DISCUSSION: The fixed posterior vault expansion increases the risk of perioperative complications due to the elevation of the posterior bone flap from the dura but allows an immediate decompression and correction of the shape, simplifying the postoperative course.

CSF shunting in myelomeningocele-related hydrocephalus and the role of prenatal imaging.

OBJECTIVE: Hydrocephalus is commonly associated with myelomeningocele (MMC). Indication and timing of cerebrospinal fluid (CSF) shunting are still a topic of discussion. The aim of this study was to investigate whether the analysis of prenatal cerebral imaging studies could provide information that is predictive of the necessity of CSF shunting in the postnatal period. MATERIAL AND METHODS: Among 73 infants operated on because of MMC between January 2003 and June 2020, 50 had undergone prenatal and postnatal MRI studies and were considered for analysis. For each patient, frontal horn width, atrial ventricle diameter, third ventricle diameter, and subarachnoid spaces (sinocortical width, craniocortical width, and the interhemispheric width) have been measured on prenatal, postnatal, and a follow-up MRI study. The need of CSF shunting device placement in relation to prenatal and early postnatal MRI data was investigated. RESULTS: Of the 50 infants, 31 (62%) developed a progressive hydrocephalus. Of these, 30 needed a CSF shunt and the majority of them (n=29) was operated on within 28 days after birth. One patient needed CSF shunt implantation at 45 days after birth and one child developed a late progressive hydrocephalus, successfully treated by ETV alone, at 14.2 months of age. All patients with an atrial ventricle diameter greater than 1.9 cm and a 3rd ventricle diameter larger than 0.3 cm on antenatal third trimester imaging have undergone CSF shunting within 1 month after birth. Conversely, all the children that did not undergo a CSF shunt placement showed an atrial cerebral ventricle diameter inferior to 1.2 cm and a 3rd ventricle width < 0.3 cm on antenatal imaging. Frontal horn width and subarachnoid CSF spaces' evolution did not seem to play a role. CONCLUSION: The prenatal MRI assessment of the associated prenatal ventriculomegaly in MMC provides parameters that have a predictive value heralding the probability of a CSF diversion procedure after birth. In the same way, the analysis of intrauterine MRI studies may identify those subjects that are less at risk of developing a progressive hydrocephalus after birth, therefore encouraging a more cautious attitude towards the early implantation of CSF shunting devices in the current clinical practice.