Cranial Repair in Children: Techniques, Materials, and Peculiar Issues.

Cranial repair in children deserves particular attention since many issues are still controversial. Furthermore, literature data offer a confused picture of outcome of cranioplasty, in terms of results and complication rates, with studies showing inadequate follow-up and including populations that are not homogeneous by age of the patients, etiology, and size of the bone defect.Indeed, age has merged in the last years as a risk factor for resorption of autologous bone flap that is still the most frequent complication in cranial repair after decompressive craniectomy.Age-related factors play a role also when alloplastic materials are used. In fact, the implantation of alloplastic materials is limited by skull growth under 7 years of age and is contraindicated in the first years if life. Thus, the absence of an ideal material for cranioplasty is even more evident in children with a steady risk of complications through the entire life of the patient that is usually much longer than surgical follow-up.As a result, specific techniques should be adopted according to the age of the patient and etiology of the defect, aiming to repair the skull and respect its residual growth.Thus, autologous bone still represents the best option for cranial repair, though limitations exist. As an alternative, biomimetic materials should ideally warrant the possibility to overcome the limits of other inert alloplastic materials by favoring osteointegration or osteoinduction or both.On these grounds, this paper aims to offer a thorough overview of techniques, materials, and peculiar issues of cranial repair in children.

Combined use of 3D printing and mixed reality technology for neurosurgical training: getting ready for brain surgery.

OBJECTIVE: Learning surgical skills is an essential part of neurosurgical training. Ideally, these skills are acquired to a sufficient extent in an ex vivo setting. The authors previously described an in vitro brain tumor model, consisting of a cadaveric animal brain injected with fluorescent agar-agar, for acquiring a wide range of basic neuro-oncological skills. This model focused on haptic skills such as safe tissue ablation technique and the training of fluorescence-based resection. As important didactical technologies such as mixed reality and 3D printing become more readily available, the authors developed a readily available training model that integrates the haptic aspects into a mixed reality setup. METHODS: The anatomical structures of a brain tumor patient were segmented from medical imaging data to create a digital twin of the case. Bony structures were 3D printed and combined with the in vitro brain tumor model. The segmented structures were visualized in mixed reality headsets, and the congruence of the printed and the virtual objects allowed them to be spatially superimposed. In this way, users of the system were able to train on the entire treatment process from surgery planning to instrument preparation and execution of the surgery. RESULTS: Mixed reality visualization in the joint model facilitated model (patient) positioning as well as craniotomy and the extent of resection planning respecting case-dependent specifications. The advanced physical model allowed brain tumor surgery training including skin incision; craniotomy; dural opening; fluorescence-guided tumor resection; and dura, bone, and skin closure. CONCLUSIONS: Combining mixed reality visualization with the corresponding 3D printed physical hands-on model allowed advanced training of sequential brain tumor resection skills. Three-dimensional printing technology facilitates the production of a precise, reproducible, and worldwide accessible brain tumor surgery model. The described model for brain tumor resection advanced regarding important aspects of skills training for neurosurgical residents (e.g., locating the lesion, head position planning, skull trepanation, dura opening, tissue ablation techniques, fluorescence-guided resection, and closure). Mixed reality enriches the model with important structures that are difficult to model (e.g., vessels and fiber tracts) and advanced interaction concepts (e.g., craniotomy simulations). Finally, this concept demonstrates a bridging technology toward intraoperative application of mixed reality.

Tacedinaline (CI-994), a class I HDAC inhibitor, targets intrinsic tumor growth and leptomeningeal dissemination in MYC-driven medulloblastoma while making them susceptible to anti-CD47-induced macrophage phagocytosis via NF-kB-TGM2 driven tumor inflammation.

BACKGROUND: While major advances have been made in improving the quality of life and survival of children with most forms of medulloblastoma (MB), those with MYC-driven tumors (Grp3-MB) still suffer significant morbidity and mortality. There is an urgent need to explore multimodal therapeutic regimens which are effective and safe for children. Large-scale studies have revealed abnormal cancer epigenomes caused by mutations and structural alterations of chromatin modifiers, aberrant DNA methylation, and histone modification signatures. Therefore, targeting epigenetic modifiers for cancer treatment has gained increasing interest, and inhibitors for various epigenetic modulators have been intensively studied in clinical trials. Here, we report a cross-entity, epigenetic drug screen to evaluate therapeutic vulnerabilities in MYC amplified MB, which sensitizes them to macrophage-mediated phagocytosis by targeting the CD47-signal regulatory protein α (SIRPα) innate checkpoint pathway. METHODS: We performed a primary screen including 78 epigenetic inhibitors and a secondary screen including 20 histone deacetylase inhibitors (HDACi) to compare response profiles in atypical teratoid/rhabdoid tumor (AT/RT, n=11), MB (n=14), and glioblastoma (n=14). This unbiased approach revealed the preferential activity of HDACi in MYC-driven MB. Importantly, the class I selective HDACi, CI-994, showed significant cell viability reduction mediated by induction of apoptosis in MYC-driven MB, with little-to-no activity in non-MYC-driven MB, AT/RT, and glioblastoma in vitro. We tested the combinatorial effect of targeting class I HDACs and the CD47-SIRPa phagocytosis checkpoint pathway using in vitro phagocytosis assays and in vivo orthotopic xenograft models. RESULTS: CI-994 displayed antitumoral effects at the primary site and the metastatic compartment in two orthotopic mouse models of MYC-driven MB. Furthermore, RNA sequencing revealed nuclear factor-kB (NF-κB) pathway induction as a response to CI-994 treatment, followed by transglutaminase 2 (TGM2) expression, which enhanced inflammatory cytokine secretion. We further show interferon-γ release and cell surface expression of engulfment ('eat-me') signals (such as calreticulin). Finally, combining CI-994 treatment with an anti-CD47 mAb targeting the CD47-SIRPα phagocytosis checkpoint enhanced in vitro phagocytosis and survival in tumor-bearing mice. CONCLUSION: Together, these findings suggest a dynamic relationship between MYC amplification and innate immune suppression in MYC amplified MB and support further investigation of phagocytosis modulation as a strategy to enhance cancer immunotherapy responses.

Second-look surgery after pediatric brain tumor resection - Single center analysis of morbidity and volumetric efficacy.

Introduction: Postoperative residual tumor can occur for intentional or unintentional reasons. Decision-making regarding second-look surgery has to weigh molecular biology, probability of total resection and prognostic relevance against potential additional morbidity. In interdisciplinary tumor boards the neurosurgeon has to estimate risk and efficacy of second-look surgery in individual cases, based on precise data. Research question: Aim of this study was to provide such data by analyzing morbidity and volumetric efficacy of second-look surgery at a designated pediatric neuro-oncology unit. Material and methods: Children who received second-look surgery in 2007-2018 after incomplete resections were analyzed retrospectively. Measurements were performed on early postoperative magnetic resonance imaging, comparing axial diameter-based measurement as well as computer-assisted volumetric analysis. Results: 59 patients (37% of the overall cohort; 21 female; mean age: 8 â€‹± â€‹5 years) received a subtotal (n â€‹= â€‹35) or near total (n â€‹= â€‹24) resection. After interdisciplinary case review, 12 of these patients received second-look surgery mainly for residual ependymoma. This led to further tumor volume reduction in all cases (new degrees of resection: subtotal â€‹= â€‹2, near total â€‹= â€‹6, gross total â€‹= â€‹4). No new permanent morbidity or perioperative mortality was observed. Discussion and conclusion: Second-look surgery did not increase mortality and permanent morbidity, had an 8% rate of transient morbidity and achieved tumor volume reduction above 95% in 75% of selected cases, with 4 additional gross total resections. Second-look surgery is safe and effective with regard to volumetric outcome parameters even in cases with good initial resections, although the role of second-look surgery regarding oncological outcome has to be further investigated in times of personalized molecular medicine.

Non-adjustable gravitational valves or adjustable valves in the treatment of hydrocephalus after aneurysmal subarachnoid hemorrhage patients?

PURPOSE: Hydrocephalus requiring permanent CSF shunting after aneurysmal subarachnoid hemorrhage (aSAH) is frequent. It is unknown which type of valve is optimal. This study evaluates if the revision rate of gravitational differential pressure valves (G-DPVs, GAV® system (B Braun)) (G-DPV) is comparable to adjustable pressure valves (Codman Medos Hakim) (APV) in the treatment of post-aSAH hydrocephalus. METHODS: The use of a gravitational differential pressure valve is placed in direct comparison with an adjustable pressure valve system. A retrospective chart review is performed to compare the revision rates for the two valve systems. RESULTS: Within the registry from Radboud University Medical Center, 641 patients with a SAH could be identified from 1 January 2013 until 1 January 2019, whereas at the Heinrich Heine University, 617 patients were identified, totaling 1258 patients who suffered from aSAH. At Radboud University Medical Center, a gravitational differential pressure valve is used, whereas at the Heinrich Heine University, an adjustable pressure valve system is used. One hundred sixty-six (13%) patients required permanent ventricular peritoneal or atrial shunting. Shunt dysfunction occurred in 36 patients: 13 patients of the 53 (25%) of the gravitational shunt cohort, and in 23 of the 113 (20%) patients with an adjustable shunt (p = 0.54). Revision was performed at a mean time of 3.2 months after implantation with the gravitational system and 8.2 months with the adjustable shunt system. Combined rates of over- and underdrainage leading to revision were 7.5% (4/53) for the gravitational and 3.5% (4/113) for the adjustable valve system (p = 0 .27). CONCLUSION: The current study does not show a benefit of a gravitational pressure valve (GAV® system) over an adjustable pressure valve (CODMAN ® HAKIM®) in the treatment of post-aSAH hydrocephalus. The overall need for revision is high and warrants further improvements in care.

The HHIP-AS1 lncRNA promotes tumorigenicity through stabilization of dynein complex 1 in human SHH-driven tumors.

Most lncRNAs display species-specific expression patterns suggesting that animal models of cancer may only incompletely recapitulate the regulatory crosstalk between lncRNAs and oncogenic pathways in humans. Among these pathways, Sonic Hedgehog (SHH) signaling is aberrantly activated in several human cancer entities. We unravel that aberrant expression of the primate-specific lncRNA HedgeHog Interacting Protein-AntiSense 1 (HHIP-AS1) is a hallmark of SHH-driven tumors including medulloblastoma and atypical teratoid/rhabdoid tumors. HHIP-AS1 is actively transcribed from a bidirectional promoter shared with SHH regulator HHIP. Knockdown of HHIP-AS1 induces mitotic spindle deregulation impairing tumorigenicity in vitro and in vivo. Mechanistically, HHIP-AS1 binds directly to the mRNA of cytoplasmic dynein 1 intermediate chain 2 (DYNC1I2) and attenuates its degradation by hsa-miR-425-5p. We uncover that neither HHIP-AS1 nor the corresponding regulatory element in DYNC1I2 are evolutionary conserved in mice. Taken together, we discover an lncRNA-mediated mechanism that enables the pro-mitotic effects of SHH pathway activation in human tumors.

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.

Structural damage burden and hypertrophic olivary degeneration in pediatric postoperative cerebellar mutism syndrome.

Cerebellar mutism syndrome (CMS) occurs in one out of four children after posterior fossa tumor surgery, with open questions regarding risk factors, pathophysiology, and prevention strategies. Because of similarities between several cerebellar syndromes, a common pathophysiology with damage to the dentato-thalamo-cortical and dentato-rubro-olivary pathways has been proposed. Hypertrophic olivary degeneration (HOD) is an imaging correlate of cerebellar injury observed for instance in stroke patients. Aim of this study was to investigate whether the occurrence and severity of CMS correlates with the extent of damage to the relevant anatomical structures and whether HOD is a time-dependent postoperative neuroimaging correlate of CMS. We performed a retrospective single center study of CMS patients compared with matched non-CMS controls. CMS occurred in 10 children (13% of the overall cohort) with a median age of 8 years. Dentate nucleus (DN) injury significantly correlated with CMS, and superior cerebellar peduncle (SCP) injury was associated by tendency. HOD was observed as a dynamic neuroimaging phenomenon in the postoperative course and its presence significantly correlated with CMS and DN injury. Children who later developed HOD had an earlier onset and tended to have longer persistence of CMS. These findings can guide surgical measures to protect the DN and SCP during posterior fossa tumor resections and to avoid a high damage burden (i.e., bilateral damage). Development of intraoperative neuromonitoring of the cerebellar efferent pathways as well as improved preoperative risk stratification could help to establish a patient-specific strategy with optimal balance between degree of resection and functional integrity.

Synthetic vascular grafts as a new treatment option for space-occupying tumor bed cysts.

INTRODUCTION: Several authors have reported the formation of slit valves as the underlying pathomechanism of space-occupying tumor bed cysts. Iatrogenic slit valves following the resection of high-grade gliomas have been linked to certain risk factors such as intraoperative opening of the ventricles and attempts to seal these. The best therapeutic management of such cystic lesions remains elusive. Several treatment options such as cyst fenestration or cystoperitoneal shunting have been employed but remain associated with high rates of recurrence. With the given complications of the above-described treatment options, the objective was to devise a new therapy option that is safe and effective and treats the slit valve itself rather than its symptoms. METHODS: Between the years of 2010 and 2020, we successfully treated four patients with high-pressure tumor bed cysts following glioma resection by implantation of synthetic ringed vascular grafts into the slit valve. RESULTS: Postoperatively, the tumor bed cysts were regressive in all patients. Moreover, none of the treatment patients developed any complications associated with the implanted vascular grafts. Revision-free survival was 10, 12, 53, and 126 months, respectively. CONCLUSION: The use of synthetic vascular grafts as a means of stenting slit valves is a safe and effective novel treatment option for high-pressure tumor bed cysts.

Profile and Prognosis of Spontaneous Lobar Intracerebral Hemorrhage: Comparison of 6-month Survival with STICH II and the MISTIE III Lobar Hemorrhage Subset.

BACKGROUND: Randomized trials on spontaneous lobar intracerebral hemorrhage (ICH) provided no convincing evidence of the superiority of surgical treatment. Since recruitment in the trials was under the premise of equipoise, a selection bias toward patients who did not need surgery or were in hopeless condition must be suspected. The aim of the actual analysis was to compare outcome and patient profile of an unselected hospital series with recent randomized trials and to develop a prognostic model. METHODS: Of 821 patients with spontaneous ICH managed at the neurosurgical department of the University Hospital Düsseldorf between 2013 and 2018, 159 had lobar bleedings. Patient characteristics, hematoma volume, treatment modality, and 6-month survival were compared with STICH II and the subset of lobar hemorrhage in the MISTIE III trial. In addition, a prognostic model for 6-month survival in our patients was developed using a random forest classifier. RESULTS: One hundred and seven patients were managed by surgical evacuation of the hematoma and 52 without surgical evacuation. Median hemorrhage volume in our surgical cohort was 66 and 42 mL in the conservative cohort, compared with 38 and 36 mL in the STICH II trial, and 46 and 47 mL in the surgical and conservative MISTIE III lobar hemorrhage subset. Median initial Glasgow Coma Scale (GCS) score was 12 in our surgical group and 11 in the conservative group, compared with 13 in the STICH II cohorts and 12 in the MISTIE III lobar hemorrhage subset. Median age in our surgical and conservative cohorts was 73 and 74 years, respectively, compared with 65 years in both STICH II cohorts and 68 years in the MISTIE II subsets. Twenty-nine percent of our surgical cohort and 55% of our conservatively managed patients deceased within the first 6 months, compared with 18 and 24%, respectively, in STICH II and 17 and 24% in the MISTIE III subset. Our prognostic model identified large hemorrhage volumes and low admission GCS score as main unfavorable prognostic factors for 6-month survival. The random forest classifier achieved a predictive accuracy of 78% and an area under curve (AUC)- value of 88% regarding survival at 6 months, on a test set independent of the training set. CONCLUSIONS: In comparison with our surgical group, the STICH II and MISTIE III cohorts, recruited under the premise of physician equipoise, underrepresented patients with large ICHs. The cohorts in the randomized trials were therefore biased toward patients with a favorable perspective under conservative management. Initial hematoma volume and admission GCS were the main prognostic factors in our patients.

Application of clinical prediction modeling in pediatric neurosurgery: a case study.

There has been an increasing interest in articles reporting on clinical prediction models in pediatric neurosurgery. Clinical prediction models are mathematical equations that combine patient-related risk factors for the estimation of an individual's risk of an outcome. If used sensibly, these evidence-based tools may help pediatric neurosurgeons in medical decision-making processes. Furthermore, they may help to communicate anticipated future events of diseases to children and their parents and facilitate shared decision-making accordingly. A basic understanding of this methodology is incumbent when developing or applying a prediction model. This paper addresses this methodology tailored to pediatric neurosurgery. For illustration, we use original pediatric data from our institution to illustrate this methodology with a case study. The developed model is however not externally validated, and clinical impact has not been assessed; therefore, the model cannot be recommended for clinical use in its current form.

Functional tracts of the cerebellum-essentials for the neurosurgeon.

The cerebellum is historically implicated in motor coordination, but accumulating modern evidence indicates involvement in non-motor domains, including cognition, emotion, and language. This correlates with the symptoms observed in postoperative cerebellar mutism syndrome (CMS). Profound knowledge of cerebellar functional topography and tractography is important when approaching cerebellar tumors, as surgical trauma to relevant structures of cerebellar pathways plays a role in the pathogenesis of CMS. The aim of this systematic review is to provide a concise overview of relevant modern neuroimaging data and cerebellar functional tracts with regard to neurosurgical procedures.

Evaluation of Volumetric Change of Intracerebral Hemorrhage in Patients Treated with Thrombolysis for Intraventricular Hemorrhage.

BACKGROUND: Intraventricular hemorrhage (IVH) is often caused by irruption of intracerebral hemorrhage (ICH) of basal ganglia or thalamus into the ventricular system. Instillation of recombinant tissue plasminogen activator (rtPA) via an external ventricular drainage (EVD) has been shown to effectively decrease IVH volumes while the impact of rtPA instillation on ICH volumes remains unclear. In this series, we analyzed volumetric changes of ICH in patients with and without intrathecal lysis therapy. METHODS: Between 01/2013 and 01/2019, 36 patients with IVH caused by hemorrhage of basal ganglia, thalamus or brain stem were treated with rtPA via an EVD (Group A). Initial volumes were determined in the first available computed tomography (CT) scan, final volumes in the last CT scan before discharge. During the same period, 41 patients with ICH without relevant IVH were treated without intrathecal lysis therapy at our neurocritical care unit (Group B). Serial CT scans were evaluated separately for changes in ICH volumes for both cohorts using OsiriX DICOM viewer. The Wilcoxon signed-rank test was performed for statistical analysis in not normally distributed variables. RESULTS: Median initial volume of ICH for treatment Group A was 6.5 ml and was reduced to 5.0 ml after first instillation of rtPA (p < 0.01). Twenty-six patients received a second treatment with rtPA (ICH volume reduction 4.5 to 3.3 ml, p < 0.01) and of this cohort further 16 patients underwent a third treatment (ICH volume reduction 3.0 ml to 1.5 ml, p < 0.01). Comparison of first and last CT scan in Group A confirmed an overall median percentage reduction of 91.7% (n = 36, p < 0.01) of ICH volumes and hematoma resolution in Group A was significantly more effective compared to non-rtPA group, Group B (percentage reduction = 68%) independent of initial hematoma volume in the regression analysis (p = 0.07, mean 11.1, 95%CI 7.7-14.5). There were no adverse events in Group A related to rtPA instillation. CONCLUSION: Intrathecal lysis therapy leads to a significant reduction in the intraparenchymal hematoma volume with faster clot resolution compared to the spontaneous hematoma resorption. Furthermore, intrathecal rtPA application had no adverse effect on ICH volume.

Correction to: Evaluation of Volumetric Change of Intracerebral Hemorrhage in Patients Treated with Thrombolysis for Intraventricular Hemorrhage.

The author name Kerim Beseoglu has been corrected and the details given in this correction are correct.

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.

Calcifying Pseudoneoplasm of Neuraxis (CAPNON) in the Posterior Third Ventricle-Challenge for Neuroendoscopy.

BACKGROUND: We report the first case of a purely intraventricular calcifying pseudoneoplasm of neuraxis (CAPNON) in the posterior third ventricle. CASE DESCRIPTION: A 63-year-old male without any previous medical history presented with Hakim triad. Imaging showed a calcified lesion of the posterior third ventricle with hydrocephalus. An endoscopic third ventriculostomy was performed. Endoscopic removal or debulking of the lesion was impossible due to its rock-hard consistency, and thus the procedure was aborted after biopsy. CONCLUSIONS: When encountering such calcified lesions within the ventricular system, especially in proximity to eloquent regions, the decision making process should include the hard consistency and parenchymal adhesions as obstacles to neuroendoscopic removal. Even for biopsy, a higher morbidity rate compared with typical soft tumors should be assumed. Although data on intraventricular CAPNON is limited, biopsy of the lesion and treatment of associated hydrocephalus appear to be the primary neurosurgical goals, followed by imaging surveillance.

From decompressive craniectomy to cranioplasty and beyond-a pediatric neurosurgery perspective.

PURPOSE: Decompressive craniectomy (DC) is an established neurosurgical emergency technique. Patient selection, optimal timing, and technical aspects related to DC and subsequent cranioplasty remain subjects of debate. For children, the overall degree of evidence is low, compared with randomized controlled trials (RCTs) in adults. METHODS: Here, we present a detailed retrospective analysis of pediatric DC, covering the primary procedure and cranioplasty. Results are analyzed and discussed in the light of modern scientific evidence, and conclusions are drawn to stimulate future research. RESULTS: The main indication for DC in children is traumatic brain injury (TBI). Primary and secondary DC is performed with similar frequency. Outcome appears to be better than that in adults, although long-term complications (especially bone flap resorption after autologous cranioplasty) are more common in children. Overt clinical signs of cerebral herniation prior to DC are predictors of poor outcome. CONCLUSIONS: We conclude that DC is an important option in the armamentarium to treat life-threatening intracranial hypertension, but further research is warranted, preferentially in a multicenter prospective registry.