Diagnosis and treatment of Chiari malformation type 1 in children: the International Consensus Document.

BACKGROUND: Chiari malformation type 1 (CM1) is a rare condition where agreed classification and treatment are still missing. The goal of this study is to achieve a consensus on the diagnosis and treatment of CM1 in children. METHODS: A multidisciplinary panel formulated 57 provisional statements based on a review of the literature. Thirty-four international experts (IE) participated in a Delphi study by independently rating each statement on a 4-point Likert scale ("strongly disagree," "disagree," "agree," "strongly agree"). Statements that were endorsed ("agree" or "strongly agree") by < 75% of raters were re-formulated, or new statements were added, and another Delphi round followed (up to a maximum of three). RESULTS: Thirty-five IE were contacted and 34 agreed to participate. A consensus was reached on 30/57 statements (52.6%) after round 1. Three statements were added, and one removed. After round 2, agreement was reached on 56/59 statements (94.9%). Finally, after round 3, which took place during the 2019 Chiari Consensus Conference (Milan, Italy), agreement was reached on 58/59 statements (98.3%) about four main sections (Definition and Classification, Planning, Surgery, Isolated Syringomyelia). Only one statement did not gain a consensus, which is the "definition of radiological failure 24 month post-surgery." CONCLUSIONS: The consensus document consists of 58 statements (24 on diagnosis, 34 on treatment), serving clinicians and researchers following children with CM1. There is a clear need for establishing an international network and registry and to promote collaborative studies to increase the evidence base and optimize the long-term care of this patient population.

Pediatric Brain Tumors: Signatures from the Intact Proteome.

The present investigation aimed to explore the intact proteome of tissues of pediatric brain tumors of different WHO grades and localizations, including medulloblastoma, pilocytic astrocytoma, and glioblastoma, in comparison with the available data on ependymoma, to contribute to the understanding of the molecular mechanisms underlying the onset and progression of these pathologies. Tissues have been homogenized in acidic water−acetonitrile solutions containing proteases inhibitors and analyzed by LC−high resolution MS for proteomic characterization and label-free relative quantitation. Tandem MS spectra have been analyzed by either manual inspection or software elaboration, followed by experimental/theoretical MS fragmentation data comparison by bioinformatic tools. Statistically significant differences in protein/peptide levels between the different tumor histotypes have been evaluated by ANOVA test and Tukey's post-hoc test, considering a p-value > 0.05 as significant. Together with intact protein and peptide chains, in the range of molecular mass of 1.3−22.8 kDa, several naturally occurring fragments from major proteins, peptides, and proteoforms have been also identified, some exhibiting proper biological activities. Protein and peptide sequencing allowed for the identification of different post-translational modifications, with acetylations, oxidations, citrullinations, deamidations, and C-terminal truncations being the most frequently characterized. C-terminal truncations, lacking from two to four amino acid residues, particularly characterizing the ß-thymosin peptides and ubiquitin, showed a different modulation in the diverse tumors studied. With respect to the other tumors, medulloblastoma, the most frequent malignant brain tumor of the pediatric age, was characterized by higher levels of thymosin ß4 and ß10 peptides, the latter and its des-IS form particularly marking this histotype. The distribution pattern of the C-terminal truncated forms was also different in glioblastoma, particularly underlying gender differences, according to the definition of male and female glioblastoma as biologically distinct diseases. Glioblastoma was also distinguished for the peculiar identification of the truncated form of the α-hemoglobin chain, lacking the C-terminal arginine, and exhibiting oxygen-binding and vasoconstrictive properties different from the intact form. The proteomic characterization of the undigested proteome, following the top-down approach, was challenging to originally investigate the post-translational events that differently characterize pediatric brain tumors. This study provides a contribution to elucidate the molecular profiles of the solid tumors most frequently affecting the pediatric age, and which are characterized by different grades of aggressiveness and localization.

Role of susceptibility-weighted imaging and intratumoral susceptibility signals in grading and differentiating pediatric brain tumors at 1.5 T: a preliminary study.

PURPOSE: Susceptibility-weighted imaging (SWI) is useful for glioma grading and discriminating between brain tumor categories in adults, but its diagnostic value for pediatric brain tumors is unclear. Here we evaluated the usefulness of SWI for pediatric tumor grading and differentiation by assessing intratumoral susceptibility signal intensity (ITSS). METHODS: We retrospectively enrolled 96 children with histopathologically diagnosed brain tumors, who underwent routine brain MRI exam with SWI (1.5 T scanner). Each tumor was assigned an ITSS score by a radiology resident and an experienced neuroradiologist, and subsequently by consensus. Statistical analyses were performed to differentiate between low-grade (LG) and high-grade (HG) tumors, histological categories, and tumor locations. Inter-reader agreement was assessed using Cohen's kappa (κ). RESULTS: The interobserver agreement was 0.844 (0.953 between first reader and consensus, and 0.890 between second reader and consensus). Among all tumors, we found a statistically significant difference between LG and HG for ITSS scores of 0 and 2 (p = 0.002). This correlation was weaker among astrocytomas alone, and became significant when considering only off-midline astrocytomas (p = 0.05). Scores of 0 and 2 were a strong discriminating factor (p = 0.001) for astrocytomas (score 0) and for embryonal, choroid plexus, germ-cell, pineal, and ependymoma tumors (score 2). No medulloblastoma showed a score of 0. CONCLUSIONS: Our preliminary ITTS results in pediatric brain tumors somewhat differed from those obtained in adult populations. These findings highlight the potential valuable role of ITSS for tumor grading and discriminating between some tumor categories in the pediatric population.

Acute presentations of intradural lipomas: case reports and a review of the literature.

BACKGROUND: Lumbosacral lipomas (LLs) may remain asymptomatic or lead to progressive neurological deterioration. However, sudden neurological deterioration is a rare and severe event. Herein, we report rare occurrences of sudden clinical deterioration in two previously asymptomatic children harbouring intradural LLs without dermal sinus tracts or signs of occult dysraphism. A review of the pertinent literature is also included. CASE PRESENTATION: One child exhibited acute deterioration because of an epidural abscess associated with a filar lipoma without a sinus tract (probably caused by haematogenous spreading from a respiratory tract multiple infection), and the other child exhibited acute deterioration because of a very large, holocord syringomyelia-like cyst associated with a small conus lipoma. Both patients were 4 years old. In case #2, a previously undetected, severe tethered cord (conus at the S3-S4 level) was also present. A complete recovery was attained after an urgent surgical operation in both cases (in addition to targeted antibiotic therapy in case #1). All cases of deterioration in the literature were caused by abscess formation in dermal sinus tracts. CONCLUSIONS: Prophylactic surgery may be indicated even in asymptomatic children that have tethered cord and surgically favourable LLs (small dorsal and filar LLs), especially if the conditions are associated with progressive syringomyelia. Similarly, intradural dermal sinus tracts should be regarded as surgery-indicated, even if the conus is in its normal position and the patient is asymptomatic because there is a consistent risk of severe, infection-related complications. Finally, asymptomatic patients with filar LLs and a normally located conus can be candidates for surgery or an accurate clinical and radiological follow-up.

Correction to: Central nervous system (CNS) neuroblastoma. A case-based update.

Unfortunately in the original publication, the affiliation provided for the author G. Tamburrini was incorrect. The correct affiliation for G. Tamburrini should read as follows.

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

BACKGROUND: Postnatal growth of neurocranium is prevalently completed in the first years of life, thus deeply affecting the clinical presentation and surgical management of pediatric neurosurgical conditions involving the skull. This paper aims to review the pertinent literature on the normal growth of neurocranium and critically discuss the surgical implications of this factor in cranial repair. METHODS: A search of the electronic database of Pubmed was performed, using the key word "neurocranium growth", thus obtaining 217 results. Forty-six papers dealing with this topic in humans, limited to the English language, were selected. After excluding a few papers dealing with viscerocranium growth or pathological conditions not related to normal neurocranium growth 18 papers were finally included into the present review. RESULTS AND CONCLUSIONS: The skull growth is very rapid in the first 2 years of life and approximates the adult volume by 7 years of age, with minimal further growth later on, which is warranted by the remodeling of the cranial bones. This factor affects the outcome of cranioplasty. Thus, it is essential to consider age in the planning phase of cranial repair, choice of the material, and critical comparison of results of different cranioplasty solutions.

Management and prevention of cranioplasty infections.

BACKGROUND: Infection may complicate the outcome of cranial repair with significant additional morbidity, related to hospitalization, surgery and long antibiotic therapy, that may become even dramatic in case of multi-resistant germs and in particular in the paediatric population. Additionally, the economic costs for the health system are obvious. Moreover, surgical decisions concerning the timing of cranioplasty and choice of the material may be strongly affected by the risk of infection. Despite, management and prevention of cranioplasty infections are not systematically treated through the literature so far. METHODS: We reviewed pertinent literature dealing with cranioplasty infection starting from the diagnosis to treatment options, namely conservative versus surgical ones. Our institutional bundle, specific to the paediatric population, is also presented. This approach aims to significantly reduce the risk of infection in first-line cranioplasty and redo cranioplasty after previous infection. CONCLUSIONS: A thorough knowledge and understanding of risk factors may lead to surgical strategies and bundles, aiming to reduce infectious complications of cranioplasty. Finally, innovation in materials used for cranial repair should also aim to enhance the antimicrobial properties of these inert materials.

Craniocerebral disproportion after decompressive craniectomy in infants: The hidden enemy of cranial repair?

INTRODUCTION: Cranioplasty aims at restoring the physiological integrity and volume of the skull. Any disproportion between the intracranial content and the volume of the container may favor the occurrence of complications. A classification of volume mismatches is proposed. A negative mismatch, consisting of intracranial content minor to skull volume, is well represented by the sinking flap. On the other side, a positive mismatch, consisting of intracranial content higher than skull volume, usually depends on CSF collection or hydrocephalus once the brain edema is regressed. Though, in children, this condition may result from physiological brain growth after decompressive craniectomy. Treatment algorithm based on this classification is presented. ILLUSTRATIVE CASE: A 1-year-old boy with a severe traumatic brain injury underwent right decompressive craniectomy, evacuation of subdural hematoma, and dural expansion at another institution. After failure of autologous bone-assisted cranioplasty for infection, a helmet was recommended in order to postpone the cranial repair. Patient was admitted to our institution 3 years later. CT scan showed brain herniation through the cranial defect, associated to a condition of acquired craniocerebral disproportion, due to the condition of "open skull". Augmented hydroxyapatite cranioplasty (CustomBone, Finceramica, Faenza, Italy) was performed in order to manage this rare condition of positive volume mismatch. Subsequent course was uneventful and no complication was recorded at 30-month follow-up. CONCLUSIONS: This illustrative case highlights the possible occurrence of a positive structural mismatch between the skull and the intracranial content after decompressive craniectomy, thus configuring a condition of acquired craniocerebral disproportion, aside of other brain or CSF complications. We firstly recognize this condition in the literature and propose it as a possible factor affecting the outcome of cranioplasty in infants and young children.

Chiari type I and hydrocephalus.

PURPOSE: The association between Chiari type I malformation (CIM) and hydrocephalus raises a great interest because of the still unclear pathogenesis and the management implications. The goal of this paper is to review the theories on the cause-effect mechanisms of such a relationship and to analyze the results of the management of this condition. METHODS: A review of the literature has been performed, focusing on the articles specifically addressing the problem of CIM and hydrocephalus and on the series reporting about its treatment. Also, the personal authors' experience is briefly discussed. RESULTS: As far as the pathogenesis is concerned, it seems clear that raised intracranial pressure due to hydrocephalus can cause a transient and reversible tonsillar caudal ectopia ("pressure from above" hypothesis), which is something different from CIM. A "complex" hypothesis, on the other hand, can explain the occurrence of hydrocephalus and CIM because of the venous engorgement resulting from the hypoplasia of the posterior cranial fossa (PCF) and the occlusion of the jugular foramina, leading to cerebellar edema (CIM) and CSF hypo-resorption (hydrocephalus). Nevertheless, such a mechanism can be advocated only in a minority of cases (syndromic craniosynostosis). In non-syndromic CIM subjects, the presence of hydrocephalus could be explained by an occlusion of the basal CSF pathways, which would occur completely in a minority of cases (only 7-10% of CIM patients show hydrocephalus) while it would be partial in the remaining cases (no hydrocephalus). This hypothesis still needs to be demonstrated. As far as the management is concerned, the strategy to treat the hydrocephalus first is commonly accepted. Because of the "obstructive" origin of CIM-related hydrocephalus, the use of endoscopic third ventriculostomy (ETV) is straightforward. Actually, the analysis of the literature, concerning 63 cases reported so far, reveals very high success rates of ETV in treating hydrocephalus (90.5%), CIM (78.5%), and syringomyelia symptoms (76%) as well as in giving a radiological improvement of both CIM (74%) and syringomyelia (89%). The failures of ETV were not attributable to CIM or syringomyelia. Only 11% of cases required PCF decompression after ETV. CONCLUSIONS: The association between CIM and hydrocephalus probably results from different, multifactorial, and not yet completely understood mechanisms, which place the affected patients in a peculiar subgroup among those constituting the heterogeneous CIM population. ETV is confirmed as the best first approach for this subset of patients.

Bony Decompression for Chiari Malformation Type I: Long-Term Follow-Up.

BACKGROUND: Several surgical techniques are used for the management of Chiari malformation type I (CM-I). Bony posterior fossa decompression is considered a good option in children, though with a higher risk of requiring reoperation. However, there is not enough evidence from the series in the literature, which are often limited by inadequate follow-up. The goal of this study was to assess the effectiveness of suboccipital craniectomy alone in children after long-term follow-up. METHODS: Forty-two children (25 female and 17 male; mean age 6.7 years), operated on with bony decompression alone, were retrospectively reviewed. All patients underwent suboccipital craniectomy. Thirty-eight children required C1 laminectomy, and 21 also underwent dural delamination on the basis of intraoperative ultrasound investigations. The outcome was assessed using the traditional measurement and the Chicago Chiari Outcome Scale (CCOS). The mean follow-up period was 11.3 years (range 5-15 years). RESULTS: Headache was the most frequent preoperative symptom (81%), followed by neck pain (40%), vertigo (40%), ataxia (26%), and upper and lower extremity paraesthesia (26%). Syringomyelia was present in 19 patients (45%). Resolution and significant improvement of preoperative clinical symptoms were observed in 36.5% and 21.5% of cases, respectively. Three children required adjunctive surgery for symptom recurrence (7%). The tonsil position and syringomyelia were normalized or improved in 50% and 79% of cases, respectively. No complications occurred. According to the CCOS scores, 69.5% of children had an excellent outcome, 28.5% had a functional outcome and 2% had an impaired outcome. CONCLUSION: Bony decompression alone is an effective, safe and long-lasting treatment for children with CM-I. A certain risk of symptom recurrence requiring new surgery exists, but it is widely counterbalanced by the low risk of complications. Careful patient selection is crucial for a good outcome. Prospective and randomized studies are needed for further validation.

Wiring or Screwing at the Craniovertebral Junction in Childhood: Past and Present Personal Experience.

BACKGROUND: Craniovertebral junction (CVJ) instrumentation and fusion in childhood are frequently performed with either sublaminar wires or screws in lateral masses, and both are considered quite safe procedures. METHODS: Our experience deals with 12 children: six (mean age 9.5 years) harbouring a congenital instability associated with Down's or Morquio's syndromes and primary os odontoideum; and six (mean age 11.5 years) with acquired iatrogenic instability due to transoral anterior decompression for different reasons (inferior clivectomy, anterior arch removal and odontoidectomy). All patients in the 'congenital group', except for one, had preoperative dynamic x-rays and underwent surgical correction by means of posterior wiring, fusion and an external orthosis. All patients in the 'iatrogenic group' had no preoperative dynamic x-rays and underwent a screwing technique with fusion and an external orthosis. RESULTS: The postoperative clinical picture had improved in all patients at the latest follow-up (observation range 63-202 months [mean 118.5 months]), with neuroradiological confirmation of satisfactory bony fusion and with neural decompression in all patients. CONCLUSION: Although it requires a more accurate preoperative neuroradiological setting, the screwing technique takes less time and is characterized by less blood loss and less postoperative discomfort than the wiring technique. The latter features confirm the simplicity, safety (continuous fluoroscopic assistance is not necessary, and there is no risk of neurovascular injuries) and lower expense (neither complex hardware devices nor neuronavigation systems are required) of the screwing technique.

Pediatric intracranial ependymoma: correlating signs and symptoms at recurrence with outcome in the second prospective AIEOP protocol follow-up.

PURPOSE: The aims of patients' radiological surveillance are to: ascertain relapse; apply second-line therapy; accrue patients in phase 1/2 protocols if second-line therapy is not standardized/curative; and assess/treat iatrogenic effects. To lessen the emotional and socioeconomic burdens for patients and families, we ideally need to establish whether scheduled radiological surveillance gives patients a better outcome than waiting for symptoms and signs to appear. METHODS: We analyzed a prospective series of 160 newly-diagnosed and treated pediatric/adolescent patients with intracranial ependymoma, comparing patients with recurrent disease identified on scheduled MRI (the RECPT group; 34 cases) with those showing signs/symptoms of recurrent disease (the SYMPPT group; 16 cases). The median follow-up was 67 months. RESULTS: No significant differences emerged between the two groups in terms of gender, age, tumor grade/site, shunting, residual disease, or type of relapse (local, distant, or concomitant). The time to relapse (median 19 months; range 5-104) and the MRI follow-up intervals did not differ between the SYMPPT and RECPT groups. The presence of signs/symptoms was an unfavorable factor for overall survival (OS) after recurrence (5-year OS: 8% vs. 37%, p = 0.001). On multivariable analysis, an adjusted model confirmed a significantly worse OS in the SYMPPT than in the RECPT patients. CONCLUSIONS: Symptomatic relapses carried a significantly worse survival for ependymoma patients than recurrences detected by MRI alone. It would therefore be desirable to identify recurrences before symptoms develop. Radiological follow-up should be retained in ependymoma patient surveillance because there is a chance of salvage treatment for relapses found on MRI.

Central nervous system (CNS) neuroblastoma. A case-based update.

BACKGROUND: Primary central nervous system (CNS) neuroblastoma is a rare intracranial tumor affecting children mainly in the first years of life. It is usually a supratentorial tumor with a wide spectrum of clinical presentation, seizures, and focal neurological deficits being the most common presenting signs. CASE DESCRIPTION: A 2-year-old child was admitted to our ward after a generalized seizure. Neurological examination was normal. Radiological studies showed a small DWI hyperintense lesion of the right rectus gyrus. Follow-up brain MRI 8 months later showed a huge growth of the tumor (90 × 80 × 65 mm) with polycyclic and apparently defined margins, cystic components, and diffuse contrast enhancement. Complete tumor removal was performed in two planned surgical steps. Histological diagnosis was CNS neuroblastoma. At a follow-up of 8 months, the child is in good clinical and neurological condition and is completing chemotherapy treatment according to the SIOP PNET 4 protocol. DISCUSSION AND CONCLUSION: A thorough review of the literature confirms that primary CNS neuroblastoma has to be considered a distinct entity. The disease related mortality is 12.5%, lower than the one usually reported for other previously described as PNETs tumors. The most relevant factors influencing prognosis are the possibility of obtaining a complete tumor removal and age more than 3 years, which allows to include radiotherapy among treatment options.

Custom-made hydroxyapatite for cranial repair in a specific pediatric age group (7-13 years old): a multicenter post-marketing surveillance study.

BACKGROUND: CustomBone Service (CBS) is a patient-specific, biocompatible, and osteoconductive device made of porous hydroxyapatite, indicated for cranial reconstruction in adults and children. Adult literature data report a failure rate of about 8%. The aim of this Post-Marketing Surveillance study is to verify the hypothesis that CBS in children aged 7-13 years old shows a failure rate not superior to adults. MATERIALS AND METHODS: Inclusion criteria were age at implantation ranging 7-13 years old, with at least 1 year elapsed from the date of surgery. The degree of satisfaction of surgeons and patients was assessed. RESULTS: Data about 76 implants in 67 patients (M:F = 41:26) were obtained from 28 centers across 7 European countries. The mean age at surgery was 10.03 ± 1.72 years, with age stratification almost equally distributed. Fifty-nine subjects received one CBS, 7 subjects two and one subject received three CBS. Main etiologies were trauma (60.5%), malformation (11.8%), bone tumor (10.5%), and cerebral tumor (7.9%). Main indications to CBS were decompression (47.4%), autologous bone resorption (18.4%), tumor resection (11.8%), malformation (9.2%), comminuted fracture (5.3%), and other materials rejection (5.3%). Main implantation sites were fronto-parieto-temporal (26.3%), parietal (23.7%), frontal (11.8%), fronto-temporal (10.5%), and parieto-temporal (7.9%). CBS was chosen as first line of treatment in 63.1% of the cases. Mean follow-up was about 36 months. Eleven adverse events (14.5%) were reported in nine devices. Five CBS required explantation (three cases of infection, one fracture, and one mobilization). Failure rate was 6.58%, which is statistically not superior to the explantation rate recorded in adults (two-sided 95%, CI 2.2-14.7%). Satisfaction of surgeons and patients was of about 95%. CONCLUSION: CBS is a safe and effective solution for cranial repair in pediatric patients. In particular, over the age of 7, CBS shows a rate of failure as low as in adults.

Nerve growth factor improves visual loss in childhood optic gliomas: a randomized, double-blind, phase II clinical trial.

Paediatric optic pathway gliomas are low-grade brain tumours characterized by slow progression and invalidating visual loss. Presently there is no strategy to prevent visual loss in this kind of tumour. This study evaluated the effects of nerve growth factor administration in protecting visual function in patients with optic pathway glioma-related visual impairment. A prospective randomized double-blind phase II clinical trial was conducted in 18 optic pathway glioma patients, aged from 2 to 23 years, with stable disease and severe visual loss. Ten patients were randomly assigned to receive a single 10-day course of 0.5 mg murine nerve growth factor as eye drops, while eight patients received placebo. All patients were evaluated before and after treatment, testing visual acuity, visual field, visual-evoked potentials, optic coherence tomography, electroretinographic photopic negative response, and magnetic resonance imaging. Post-treatment evaluations were repeated at 15, 30, 90, and 180 days Brain magnetic resonance imaging was performed at baseline and at 180 days. Treatment with nerve growth factor led to statistically significant improvements in objective electrophysiological parameters (electroretinographic photopic negative response amplitude at 180 days and visual-evoked potentials at 30 days), which were not observed in placebo-treated patients. Furthermore, in patients in whom visual fields could still be measured, visual field worsening was only observed in placebo-treated cases, while three of four nerve growth factor-treated subjects showed significant visual field enlargement. This corresponded to improved visually guided behaviour, as reported by the patients and/or the caregivers. There was no evidence of side effects related to nerve growth factor treatment. Nerve growth factor eye drop administration appears a safe, easy and effective strategy for the treatment of visual loss associated with optic pathway gliomas.

Problems of reconstructive cranioplasty after traumatic brain injury in children.

Cranial repair after traumatic brain injury in children is still burdened by unsolved problems and controversial issues, mainly due to the high rate of resorption of autologous bone as well as the absence of valid alternative material to replace the autologous bone. Indeed, inert biomaterials are associated to satisfactory results in the short period but bear the continuous risk of complications related to the lack of osteointegration capacity. Biomimetic materials claiming osteoconductive properties that could balance their mechanical limits seem to allow good cranial bone reconstruction. However, these results should be confirmed in the long term and in larger series. Further complicating factors that may affect cranial reconstruction after head injury should be identified in the possible associated alterations of CSF dynamics and in difficulties to manage the traumatic skin lesion and the surgical wound, which also might impact on the cranioplasty outcome. All the abovementioned considerations should be taken into account when dealing with the cranial reconstruction after decompressive craniectomy in children.

Myelomeningocele Repair: Surgical Management Based on a 30-Year Experience.

BACKGROUND: Myelomeningocele (MMC) is a rare but severe spinal defect resulting from a failed neurulation process. Surgical repair is a delicate procedure that needs accurate neuroanatomical knowledge and adequate surgical planning. MATERIALS AND METHODS: The authors report on the main problems of the surgical management of this type of dysraphism. The technique used for reconstruction, and the management strategies, are analyzed according to the authors' experience with more than 600 cases, in comparison with the relevant literature. RESULTS: Tip and tricks of more than 30 years of MMC surgical management are reported, with special mention of the timing of surgery, the management of early hydrocephalus, and the principles of the repair, from the dissection to the closure of five separate layers (arachnoid, dura, muscular fascia, subcutaneous layer, skin). CONCLUSIONS: Accuracy and attention to the reconstruction are crucial for achieving good results and avoiding perioperative complications.

Shunt malfunction mimicking a cystic tumour.

Shunt malfunction represents one of the most common problem to deal with in the daily neurosurgical practice. Among the variety of possible presentations, the cyst-like dilatation of the brain around the proximal catheter is one of the most rare and misleading type. The case of a boy with a 'tumour-like' proximal shunt malfunction is described and the pertinent literature is analysed.

Cavum septi pellucidi cysts: a survey about clinical indications and surgical management strategies.

INTRODUCTION: Cavum septi pellucidi (CSP) cysts have a very low incidence (0.04%). Symptomatic patients usually present aspecific symptoms. For this reason, the management of these patients is still debated. MATERIALS AND METHODS: We selected the case of a ten year old patient, with a clinical history of frontal morning headaches and difficulty in concentration. Brain MRI documented a septum pellucidum cyst and a moderate biventricular dilation. We submitted the case, and a questionnaire concerning indications to surgery and management options to an international group of 54 pediatric neurosurgeons, analyzing the results and comparing them with the current literature. RESULTS: The majority of the participants (50%) indicated as appropriate at the early stage only a clinical observation. In case of persistence of clinical symptoms, 58% opted for intracranial pressure (ICP) monitoring, which, if raised, was considered by 91% as an adequate indication to proceed with surgical treatment. A total of 98% of the participants indicated endoscopic fenestration of the cyst as the preferred surgical strategy. CONCLUSIONS: The management of symptomatic patients with CSP cyst is controversial. Our results suggest that in most of the patients with aspecific symptoms, clinical observation and eventually ICP monitoring are adequate to identify patients for surgery.

Role of "major" and "minor" lambdoid arch sutures in posterior cranial fossa changes: mechanism of cerebellar tonsillar herniation in infants with multisutural craniosynostosis.

PURPOSE: This study aimed to explain the functional role of lambdoid arch sutures in the development of cerebellar tonsillar herniation. Posterior cranial fossa (PCF) changes were investigated in infants with premature synostosis of the major and minor sutures of the lambdoid arch without premature synostosis of the PCF synchondroses. METHODS: Morphometric and volumetric PCF measurements were performed on preoperative high-resolution CT studies in 12 infants with multisutural craniosynostosis involving the lambdoid arch and compared with those of 12 age-matched healthy subjects. RESULTS: All 12 patients had hypoplasia of PCF bone structures and normal volumes of the PCF and neural structures. PCF hypoplasia was related to exocciput length in infants with isolated involvement of major sutures, while it was related to posterior skull base hemifossae in infants with isolated involvement of minor lambdoid arch sutures. Foramen magnum AP diameter was reduced in babies with major suture involvement and tonsillar herniation, while foramen magnum AP and LL diameters were reduced in babies with minor suture involvement without tonsillar herniation. Right and left jugular foramen (JF) areas differed in all infants; however, the area of the smaller JF was significantly reduced only in infants with involvement of minor lambdoid arch sutures. CONCLUSION: Hypoplasia of PCF bone structures due to sutural synostosis of the lambdoid arch is a required predisposing but not sufficient factor for the development of cerebellar tonsillar herniation through the foramen magnum. Normal PCF volume and foramen magnum anatomy may partly explain the development of cerebellar tonsil herniation in infants with lambdoid arch synostosis.