Frontal bone resorption after fronto-facial monobloc advancement in FGFR-related craniosynostoses: predictive factors.

BACKGROUND: Fronto-facial monobloc advancement with internal distraction (FFMBA) is a central procedure in the management of FGFR-related craniosynostoses. Children undergoing FFMBA may present with resorption of the frontal bony flap in the months or years following surgery. Here, we aimed at identifying the clinical factors associated with resorption and its extent in patients with Crouzon and Pfeiffer syndromes. METHODS: We conducted a retrospective monocentric study of children with Crouzon and Pfeiffer syndromes who underwent FFMBA between May 2008 and October 2021, with available CT-scan data (1) early after surgery before the initiation of distraction, (2) at the end of distraction, (3) 2 years after surgery and optionally (4) 5 years or more after surgery. The following parameters were included: sex, age, mutation, number of previous craniofacial procedures, presence of tracheostomy or ventriculo-peritoneal (VP) shunt, FFMBA indication (raised ICP, OSAS, exorbitism, morphology), per-operative parameters (use of osteosynthesis, per-operative advancement, duration of surgery) and post-operative parameters (CSF leak, infection, distraction initiation, total advancement, persistence of a retro-frontal dead space). RESULTS: 63 patients were included, with a mean age of 2.91 years (SD=1.61) at the time of surgery, male/female sex ratio of 1.1, and a majority of Crouzon syndrome (84%). Two years after surgery (average: 622 days, SD=286.7), mean frontal bone flap resorption was 4.83 cm2 ([0-27.3], SD=5.35). Factors associated with more severe frontal bone resorption were the intraoperative use of absorbable sutures vs steel wires (9.83 vs. 3.99, p=0.04) and the persistence of a retro-frontal dead space at 2 years after surgery (13.12 vs. 3.63, p<0.001). CONCLUSION: The use of absorbable sutures for frontal bone fixation in FFMBA and the persistence of a retro-frontal dead space two years after surgery are risk factors for bone resorption. This report indicates that rigid osteosynthesis should be favored, and both per-operative and early post-operative distractor activation should be performed with care and follow-up of brain expansion.

Sotorasib for Vascular Malformations Associated with KRAS G12C Mutation.

KRAS gain-of-function mutations are frequently observed in sporadic arteriovenous malformations. The mechanisms underlying the progression of such KRAS-driven malformations are still incompletely understood, and no treatments for the condition are approved. Here, we show the effectiveness of sotorasib, a specific KRAS G12C inhibitor, in reducing the volume of vascular malformations and improving survival in two mouse models carrying a mosaic Kras G12C mutation. We then administered sotorasib to two adult patients with severe KRAS G12C-related arteriovenous malformations. Both patients had rapid reductions in symptoms and arteriovenous malformation size. Targeting KRAS G12C appears to be a promising therapeutic approach for patients with KRAS G12C-related vascular malformations. (Funded by the European Research Council and others.).

Prognostic Impact of Hypothalamic Perforation in Adult Patients With Craniopharyngioma: A Cohort Study.

CONTEXT: Outcome of craniopharyngioma is related to its locoregional extension, which impacts resectability and the risk of surgical complications. To maximize resection and minimize complications, optic tract localization, temporal lobe extension, and hypothalamic involvement are essential factors for surgical management. OBJECTIVE: To assess the outcome of craniopharyngiomas depending on their relation to the hypothalamus location. METHODS: We conducted a retrospective analysis of 79 patients with a craniopharyngioma who underwent surgery from 2007 to 2022. Craniopharyngiomas were classified in 3 groups, depending on the type of hypothalamus involvement assessed by preoperative magnetic resonance imaging: infra-hypothalamic (type A, n = 33); perforating the hypothalamus (type B, n = 40); and supra-hypothalamic (type C, n = 6). Surgical strategy was guided by the type of hypothalamic involvement, favoring endonasal approaches for type A and type B, and transcranial approaches for type C. RESULTS: Long-term disease control was achieved in 33/33 (100%), 37/40 (92%), and 5/6 (83%) patients in type A, B, and C, respectively. In type B, vision was improved in 32/36 (89%) patients, while hypothalamic function was improved, stable, or worsened in 6/40 (15%), 32/40 (80%), and 2/40 (5%) patients, respectively. Papillary craniopharyngiomas were found in 5/33 (15%), 9/40 (22%), and 3/6 (50%) patients in types A, B, and C, respectively. In 4 patients, BRAF/MEK inhibitors were used, with significant tumor shrinkage in all cases. CONCLUSION: Craniopharyngiomas located below the hypothalamus or perforating it can be safely treated by transsphenoidal surgery. For supra-hypothalamic craniopharyngiomas, postoperative results are less favorable, and documenting a BRAF mutation may improve outcome, if targeted therapy was efficient enough to replace surgical debulking.

The pontine diffuse midline glioma, EGFR-subtype with ependymal features: Yet another face of diffuse midline glioma, H3K27-altered.

Diffuse midline glioma with two components: classical glial and ependymal.

Laser interstitial thermal therapy is effective and safe for the treatment of brain tumors in NF1 patients after cerebral revascularization for moyamoya angiopathy: a report on two cases.

Background: The co-occurrence of moyamoya vasculopathy and extra-optic pathway tumors is rare in neurofibromatosis type 1 (NF1), with only four cases described in the literature. Brain surgery in these patients may be challenging because of the risk of brain infarction after skin and dural incision. Given its percutaneous and minimally invasive nature, laser interstitial thermal therapy (LITT) is an ideal option for the treatment of brain tumors in these patients. Here, we report on two patients with NF1 and moyamoya syndrome (MMS) treated for a brain glioma with LITT, after cerebral revascularization. Cases: The first patient, with familial NF1, underwent bilateral indirect revascularization with multiple burr holes (MBH) for symptomatic MMS. Two years later, she was diagnosed with a left temporal tumor, with evidence of radiologic progression over 10 months. The second patient, also with familial NF1, developed unilateral MMS when he was 6 years old and was treated with MBH. At the age of 15 years, MRI showed a right cingular lesion, growing on serial MRIs. Both patients underwent LITT with no perioperative complications; they are progression free at 10 and 12 months, respectively, and the tumors have decreased in volume. Discussion: While the association of extra-optic neoplasm and moyamoya angiopathy is seldom reported in NF1, tumor treatment is challenging in terms of both avoiding stroke and achieving oncological control. Here, we show in 2 cases, that LITT could be a safe and effective option in these rare conditions.

Case Report: Zolpidem's paradoxical restorative action: A case report of functional brain imaging.

Zolpidem is a sedative drug that has been shown to induce a paradoxical effect, restoring brain function in wide range of neurological disorders. The underlying functional mechanism of the effect of zolpidem in the brain in clinical improvement is still poorly understood. Thus, we aimed to investigate rest brain function to study zolpidem-induced symptom improvement in a patient who developed postoperative pediatric cerebellar mutism syndrome, a postoperative complication characterized by delayed onset transient mutism/reduced speech that can occur after medulloblastoma resection. The patient experienced clinical recovery after a single dose of zolpidem. Brain function was investigated using arterial spin labeling MRI and resting-state functional MRI. Imaging was performed at three time-points: preoperative, postoperative during symptoms, and after zolpidem intake when the symptoms regressed. Whole brain rest cerebral blood flow (CBF) and resting state functional connectivity using Pearson coefficient correlations between pairs of regions of interest were investigated two-by-two at the different time points. A comparison between postoperative and preoperative images showed a significant decrease in rest CBF in the left supplementary motor area, Broca's area, and the left striatum and a decrease in functional connectivity within the dentato-thalamo-cortical and cortico-striato-pallido-thalamo-cortical loops. Post-zolpidem images showed increased CBF in the left striatum and increased functional connectivity within the disrupted loops relative to postoperative images. Thus, we observed functional changes within the broader speech network and thalamo-subcortical interactions associated with the paradoxical effect of zolpidem in promoting clinical recovery. This should encourage further functional investigations in the brain to better understand the mechanism of zolpidem in neurological recovery.

The Management of Hydrocephalus in Midline Posterior Fossa Cystic Collections: Surgical Outcome From a Retrospective Single-Center Case Series of 54 Consecutive Pediatric Patients.

BACKGROUND: Hydrocephalus frequently occurs with midline posterior fossa cystic collections. The classification of this heterogeneous group of developmental anomalies, including Dandy-Walker malformation, persisting Blake's pouch, retrocerebellar arachnoid cysts, and mega cisterna magna, is subject of debate. The absence of diagnostic criteria is confusing regarding the ideal management of PFCC-related hydrocephalus. OBJECTIVE: To decipher the surgical strategy for the treatment of children with PFCC-related hydrocephalus through a retrospective analysis of the surgical outcome driven by their clinical and radiological presentation. METHODS: This study enrolled patients operated of symptomatic PFCC-related hydrocephalus. Clinical and MRI features were examined, as well as the surgical outcome. Unbiased subgroup classification of the patients was performed with multiple component analysis as a function of imaging characteristics and hierarchical clustering on principal component. Outcome was assessed with binomial logistic regression and Kaplan-Meier analysis. RESULTS: Fifty-four patients were included between 2007 and 2021. Multiple component analysis suggested that cerebellar and vermian hypoplasia, vermian rotation, basal-tentorial angle, and fastigial angle were strongly correlated. Hierarchical clustering and the distribution of the patients in the bidimensional plot showed the clear segregation of 3 major clusters, which correlated with the radiological diagnosis ( P < .01). Binomial logistic regression and survival analysis showed that endoscopic third ventriculostomy was an effective treatment for patients with persisting Blake's pouch, while failing to control hydrocephalus in most of patients with Dandy-Walker malformation. CONCLUSION: Preoperative MRI in patients with PFCC-related hydrocephalus is essential to better define the diagnosis. The choice of treatment strategy notably relies on correct radiological diagnosis.

Pediatric spinal pilocytic astrocytomas form a distinct epigenetic subclass from pilocytic astrocytomas of other locations and diffuse leptomeningeal glioneuronal tumours.

Pediatric spinal low-grade glioma (LGG) and glioneuronal tumours are rare, accounting for less 2.8-5.2% of pediatric LGG. New tumour types frequently found in spinal location such as diffuse leptomeningeal glioneuronal tumours (DLGNT) have been added to the World Health Organization (WHO) classification of tumours of the central nervous system since 2016, but their distinction from others gliomas and particularly from pilocytic astrocytoma (PA) are poorly defined. Most large studies on this subject were published before the era of the molecular diagnosis and did not address the differential diagnosis between PAs and DLGNTs in this peculiar location. Our study retrospectively examined a cohort of 28 children with LGGs and glioneuronal intramedullary tumours using detailed radiological, clinico-pathological and molecular analysis. 25% of spinal PAs were reclassified as DLGNTs. PA and DLGNT are nearly indistinguishable in histopathology or neuroradiology. 83% of spinal DLGNTs presented first without leptomeningeal contrast enhancement. Unsupervised t-distributed stochastic neighbor embedding (t-SNE) analysis of DNA methylation profiles showed that spinal PAs formed a unique methylation cluster distinct from reference midline and posterior fossa PAs, whereas spinal DLGNTs clustered with reference DLGNT cohort. FGFR1 alterations were found in 36% of spinal tumours and were restricted to PAs. Spinal PAs affected significantly younger patients (median age 2 years old) than DLGNTs (median age 8.2 years old). Progression-free survival was similar among the two groups. In this location, histopathology and radiology are of limited interest, but molecular data (methyloma, 1p and FGFR1 status) represent important tools differentiating these two mitogen-activated protein kinase (MAPK) altered tumour types, PA and DLGNT. Thus, these molecular alterations should systematically be explored in this type of tumour in a spinal location.

Chiari malformation type I surgery in children: French multicenter 10-year cohort.

OBJECTIVE: Chiari malformation type I (CM-I) is frequent in children and remains a surgical challenge. Several techniques have been described for posterior fossa decompression. No decision algorithm has been validated, and strategies are highly variable between institutions. The goal of this study was to define therapeutic guidelines that take into consideration patient specificities. METHODS: The authors retrospectively collected data from patients who were < 18 years of age, were diagnosed with CM-I, and were treated surgically between 2008 and 2018 in 8 French pediatric neurosurgical centers. Data on clinical features, morphological parameters, and surgical techniques were collected. Clinical outcomes at 3 and 12 months after surgery were assessed by the Chicago Chiari Outcome Scale. The authors used a hierarchical clustering method to define clusters of patients by considering their anatomical similarities, and then compared outcomes between surgical strategies in each of these clusters. RESULTS: Data from 255 patients were collected. The mean age at surgery was 9.6 ± 5.0 years, syringomyelia was reported in 60.2% of patients, the dura mater was opened in 65.0% of patients, and 17.3% of patients underwent a redo surgery for additional treatment. The mean Chicago Chiari Outcome Scale score was 14.4 ± 1.5 at 3 months (n = 211) and 14.6 ± 1.9 at 12 months (n = 157). The hierarchical clustering method identified three subgroups with potentially distinct mechanisms underlying tonsillar herniation: bony compression, basilar invagination, and foramen magnum obstruction. Each cluster matched with specific outcomes. CONCLUSIONS: This French multicenter retrospective cohort study enabled the identification of three subgroups among pediatric patients who underwent surgery for CM-I, each of which was associated with specific outcomes. This morphological classification of patients might help in understanding the underlying mechanisms and providing personalized treatment.

The dural angioleiomyoma harbors frequent GJA4 mutation and a distinct DNA methylation profile.

The International Society for the Study of Vascular Anomalies (ISSVA) has defined four vascular lesions in the central nervous system (CNS): arteriovenous malformations, cavernous angiomas (also known as cerebral cavernous malformations), venous malformations, and telangiectasias. From a retrospective central radiological and histopathological review of 202 CNS vascular lesions, we identified three cases of unclassified vascular lesions. Interestingly, they shared the same radiological and histopathological features evoking the cavernous subtype of angioleiomyomas described in the soft tissue. We grouped them together with four additional similar cases from our clinicopathological network and performed combined molecular analyses. In addition, cases were compared with a cohort of 5 soft tissue angioleiomyomas. Three out 6 CNS lesions presented the same p.Gly41Cys GJA4 mutation recently reported in hepatic hemangiomas and cutaneous venous malformations and found in 4/5 soft tissue angioleiomyomas of our cohort with available data. Most DNA methylation profiles were not classifiable using the CNS brain tumor (version 12.5), and sarcoma (version 12.2) classifiers. However, using unsupervised t-SNE analysis and hierarchical clustering analysis, 5 of the 6 lesions grouped together and formed a distinct epigenetic group, separated from the clusters of soft tissue angioleiomyomas, other vascular tumors, inflammatory myofibroblastic tumors and meningiomas. Our extensive literature review identified several cases similar to these lesions, with a wide variety of denominations. Based on radiological and histomolecular findings, we suggest the new terminology of "dural angioleiomyomas" (DALM) to designate these lesions characterized by a distinct DNA methylation pattern and frequent GJA4 mutations.

Pediatric brainstem cavernous malformations: 2-center experience in 40 children.

OBJECTIVE: Brainstem cavernous malformations (BSCMs) are relatively uncommon, low-flow vascular lesions in children. Given the paucity of data, guidelines regarding the clinical management of BSCMs in children are lacking and the surgical indication is most commonly based on an individual surgeon's judgment and experience. The goal in this study was to evaluate the clinical behavior of BSCMs in childhood and the long-term outcome in children managed conservatively and surgically. METHODS: This was an observational, retrospective study including all children with BSCMs who were followed at 2 institutions between 2008 and 2020. RESULTS: The study population consisted of 40 children (27 boys, 67.5%) with a mean age of 11.4 years. Twenty-three children (57.5%) were managed conservatively, whereas 17 children (42.5%) underwent resection of BSCMs. An aggressive clinical course was observed in 13 children (32.5%), who experienced multiple hemorrhages with a progressive pattern of neurological decline. Multiple BSCMs were observed in 8 patients, of whom 3 patients presented with a complex of multiple tightly attached BSCMs and posed a significant therapeutic challenge. The overall long-term outcome was favorable (modified Rankin Scale [mRS] scores 0-2) in 36 patients (90%), whereas an unfavorable outcome (mRS scores 3 and 4) was seen in 4 children (10%). An mRS score of 5 or 6 was not observed. The mean (± SD) follow-up was 88.0 (± 92.6) months. CONCLUSIONS: The clinical course of BSCMs in children is highly variable, with benign lesions on the one hand and highly aggressive lesions with repetitive hemorrhages on the other. Given the greater life expectancy and the known higher functional recovery in children, surgical treatment should be considered early in young patients presenting with surgically accessible lesions and an aggressive clinical course, and it should be performed in a high-volume center.

Pediatric brain arteriovenous malformation recurrence: a cohort study, systematic review and meta-analysis.

BACKGROUND: Recurrence following obliteration of brain arteriovenous malformations (AVMs) is common in children surgically treated, but recurrences following endovascular (EVT) and radiosurgical approaches are scantily reported. OBJECTIVE: To analyze the rates and risk factors for AVM recurrence after obliteration in a single-center cohort of children with ruptured AVMs treated with multimodal approaches, and to carry out a comprehensive review and meta-analysis of current data. METHODS: Children with ruptured AVMs between 2000 and 2019 enrolled in a prospective registry were retrospectively screened and included after angiographically determined obliteration to differentiate children with/without recurrence. A complementary systematic review and meta-analysis of studies investigating AVM recurrence in children between 2000 and 2020 was aggregated to explore the overall recurrence rates across treatment modalities by analyzing surgery versus other treatments. RESULTS: Seventy children with obliterated AVMs were included. AVM recurrences (n=10) were more commonly treated with EVT as final treatment (60% in the recurrence vs 13.3% in the no-recurrence group, p=0.018). Infratentorial locations were associated with earlier and more frequent recurrences (adjusted relative risk=4.62, 95% CI 1.08 to 19.04; p=0.04).In the aggregate analysis, the pooled rate of AVM recurrence was 10.9% (95% CI 8.7% to 13.5%). Younger age at presentation was associated with more frequent recurrences (RR per year increase, 0.97, 95% CI 0.93 to 0.99; p=0.046). CONCLUSION: Location of infratentorial AVMs and younger age at presentation may be associated with earlier and more frequent recurrences. The higher rates of recurrence in patients with AVMs obliterated with EVT questions its role in an intent-to-cure approach and reinforces its position as an adjunct to surgery and/or radiosurgery.

Etiology of intracerebral hemorrhage in children: cohort study, systematic review, and meta-analysis.

OBJECTIVE: Understanding the etiological spectrum of nontraumatic pediatric intracerebral hemorrhage (pICH) is key to the diagnostic workup and care pathway. The authors aimed to evaluate the etiological spectrum of diseases underlying pICH. METHODS: Children treated at the authors' institution for a pICH were included in an inception cohort initiated in 2008 and retrospectively inclusive to 2000, which was analyzed in October 2019. They then conducted a systematic review of relevant articles in PubMed published between 1990 and 2019, identifying cohorts with pICH. Identified populations and patients from the authors' cohort were pooled in a multicategory meta-analysis. RESULTS: A total of 243 children with pICH were analyzed in the cohort study. The final primary diagnosis was an intracranial vascular lesion in 190 patients (78.2%), a complication of a cardiac disease in 17 (7.0%), and a coagulation disorder in 14 (5.8%). Hematological and cardiological etiologies were disproportionately more frequent in children younger than 2 years (p < 0.001). The systematic review identified 1309 children in 23 relevant records pooled in the meta-analysis. Overall, there was significant heterogeneity. The dominant etiology was vascular lesion, with an aggregate prevalence of 0.59 (95% CI 0.45-0.64; p < 0.001, Q = 302.8, I2 = 92%). In 18 studies reporting a detailed etiological spectrum, arteriovenous malformation was the dominant etiology (68.3% [95% CI 64.2%-70.9%] of all vascular causes), followed by cavernoma (15.7% [95% CI 13.0%-18.2%]). CONCLUSIONS: The most frequent etiology of pICH is brain arteriovenous malformation. The probability of an underlying vascular etiology increases with age, and, conversely, hematological and cardiac causes are dominant causes in children younger than 2 years.

Acute surgical management of children with ruptured brain arteriovenous malformation.

OBJECTIVE: Rupture of brain arteriovenous malformation (AVM) is the main etiology of intracerebral hemorrhage (ICH) in children. Ensuing intracranial hypertension is among the modifiable prognosis factors and sometimes requires emergency hemorrhage evacuation (HE). The authors aimed to analyze variables associated with HE in children with ruptured AVM. METHODS: This study was a single-center retrospective analysis of children treated for ruptured AVM. The authors evaluated the occurrence of HE, its association with other acute surgical procedures (e.g., nidal excision, decompressive hemicraniectomy), and clinical outcome. Variables associated with each intervention were analyzed using univariable and multivariable models. Clinical outcome was assessed at 18 months using the ordinal King's Outcome Scale for Childhood Head Injury. RESULTS: A total of 104 patients were treated for 112 episodes of ruptured AVM between 2002 and 2018. In the 51 children (45.5% of cases) who underwent HE, 37 procedures were performed early (i.e., within 24 hours after initial cerebral imaging) and 14 late. Determinants of HE were a lower initial Glasgow Coma Scale score (adjusted odds ratio [aOR] 0.83, 95% CI 0.71-0.97 per point increase); higher ICH/brain volume ratio (aOR 18.6, 95% CI 13-26.5 per percent increase); superficial AVM location; and the presence of a brain herniation (aOR 3.7, 95% CI 1.3-10.4). Concurrent nidal surgery was acutely performed in 69% of Spetzler-Martin grade I-II ruptured AVMs and in 25% of Spetzler-Martin grade III lesions. Factors associated with nidal surgery were superficial AVMs, late HE, and absent alteration of consciousness at presentation. Only 8 cases required additional surgery due to intracranial hypertension. At 18 months, overall mortality was less than 4%, 58% of patients had a favorable outcome regardless of surgical intervention, and 87% were functioning independently. CONCLUSIONS: HE is a lifesaving procedure performed in approximately half of the children who suffer AVM rupture. The good overall outcome justifies intensive initial management.

Endoscopic aqueductal stenting in the management of pediatric hydrocephalus.

OBJECTIVE: Pediatric patients with long-term shunts may experience specific complications related to the segregation of the supra- and infratentorial spaces along with different pressure regimens, leading to either mesencephalic syndromes during shunt dysfunction or isolated fourth ventricle (IFV). An accepted treatment to reestablish normal CSF pathways and reequilibrate the transtentorial pressures is endoscopic aqueductal stenting (EAS) to avoid restenosis. In the present paper, the authors studied children treated with EAS during the last decade for both IFV and obstructive hydrocephalus, evaluated its impact on the course of the disease, and identified prognostic factors for EAS success. METHODS: A noninterventional retrospective study of routinely acquired data was performed, including all hydrocephalic children undergoing EAS between 2011 and 2019 at Hôpital Necker, Paris, France. The following variables were analyzed: etiology of hydrocephalus; number of surgeries before and after stent placement; indication for EAS; type of stent connection (i.e., connected or not to a ventriculoperitoneal shunt); and the stent position. Stent failure was defined as the need to perform further shunt revision. Univariate and multivariate analyses were run to identify factors associated with stent failure. RESULTS: Seventeen patients with a mean age at stent placement of 6 years (SD 6.5 years, range 1 month-18 years) and with a mean follow-up after EAS of 47.5 months (SD 33.7 months, range 5-120 months) were included in the analysis. The etiology of hydrocephalus was as follows: obstructive tumoral (41%), posthemorrhagic (35%), postinfectious (12%), and dysraphism related (12%). The indication for EAS was IFV (47%), rostral midbrain dysfunction syndrome (35%), prevention of secondary aqueductal stenosis after debulking surgery (12%), or primary aqueductal stenosis (6%). No transient or permanent neurological deficits related to the procedure were observed. After EAS, 10 patients did not require further surgeries (59%), and for the others the number of hydrocephalus-related surgeries significantly decreased after stenting. In univariate analysis posthemorrhagic etiology and prevention of aqueductal stenosis were identified as predictors of a good outcome, whereas in multivariate analysis posthemorrhagic hydrocephalus was found to predict a favorable outcome. CONCLUSIONS: The results confirm EAS as a first-line treatment for IFV and suggest its efficacy in changing the history of hydrocephalic patients who have undergone multiple operations and who experience rostral midbrain dysfunction syndrome, as well as efficacy in the prevention of aqueductal stenosis in selected cases of obstructive tumoral hydrocephalus.