GNAQ/GNA11 Mosaicism Is Associated with Abnormal Serum Calcium Indices and Microvascular Neurocalcification.

Mosaic mutations in genes GNAQ or GNA11 lead to a spectrum of diseases including Sturge-Weber syndrome and phakomatosis pigmentovascularis with dermal melanocytosis. The pathognomonic finding of localized "tramlining" on plain skull radiography, representing medium-sized neurovascular calcification and associated with postnatal neurological deterioration, led us to study calcium metabolism in a cohort of 42 children. In this study, we find that 74% of patients had at least one abnormal measurement of calcium metabolism, the commonest being moderately low serum ionized calcium (41%) or high parathyroid hormone (17%). Lower levels of ionized calcium even within the normal range were significantly associated with seizures, and with specific antiepileptics despite normal vitamin D levels. Successive measurements documented substantial intrapersonal fluctuation in indices over time, and DEXA scans were normal in patients with hypocalcemia. Neurohistology from epilepsy surgery in five patients revealed not only intravascular, but perivascular and intraparenchymal mineral deposition and intraparenchymal microvascular disease in addition to previously reported findings. Neuroradiology review clearly demonstrated progressive calcium deposition in individuals over time. These findings and those of the adjoining paper suggest that calcium deposition in the brain of patients with GNAQ/GNA11 mosaicism may not be a nonspecific sign of damage as was previously thought, but may instead reflect the central postnatal pathological process in this disease spectrum.

Foramen magnum decompression with cervical syringotomy for Chiari malformation type I with syringomyelia - A useful adjunct in selected cases.

Background: Persistent or worsening syringomyelia after foramen magnum decompression (FMD) for Chiari I malformation (CIM) can be challenging to manage. We present a previously unpublished surgical technique of FMD with concomitant cervical syringotomy in selected patients. Methods: A retrospective analysis of prospectively collected data was carried out. Patients who underwent FMD and expansion duraplasty (FMDD) with concomitant syringotomy were collected. Results: Three patients with CIM with high cervical syringomyelia who underwent FMDD with concurrent syringotomy were identified. All cases had an idiopathic CIM. Improvement in clinical symptoms was noticed in all patients. Early postoperative imaging (within 6 weeks-4 months) showed syrinx transverse diameter reduction in the range of 85-100%. There were no postoperative complications. Conclusion: FMDD with concurrent high cervical syringotomy through a standard approach in selected cases of CIM with high cervical syringes achieves clinical improvement without additional complications.

Gastrulation and Split Cord Malformation.

Split cord malformation (SCM) is a rare form of closed spinal dysraphism, in which two hemi-cords are present, instead of a single spinal cord. SCM is categorised into type 1 and type 2. Type 1 SCM is defined by the presence of a bony or osseocartilaginous spur between the hemi-cords, whereas type 2 SCM has no bony spur, and the two hemi-cords are contained within a single dura. In this chapter, we present the putative mechanisms by which SCM arises, including gastrulation defects and Pang's unified theory. The typical and rare clinical presentations and variations are described. Finally, we outline the step-by-step surgical approach to both SCM 1 and 2 and the overall prognosis of both conditions.

Occipitocervical instrumented fixation utilising patient-specific C2 3D-printed spinal screw trajectory guides in complex paediatric skeletal dysplasia.

PURPOSE: Instability of the craniocervical junction in paediatric patients with skeletal dysplasia poses a unique set of challenges including anatomical abnormalities, poor bone quality, skeletal immaturity and associated general anaesthetic risks. Instrumented fixation provides optimal stabilisation and fusion rates. The small vertebrae make the placement of C2 pedicle screws technically demanding with low margins of error between the spinal canal and the vertebral artery. METHODS: We describe a novel clinical strategy utilising 3D-printed spinal screw trajectory guides (3D-SSTG) for individually planned C2 pedicle and laminar screws. The technique is based on a pre-operative CT scan and does not require intraoperative CT imaging. This reduces the radiation burden to the patient and forgoes the associated time and cost. The time for model generation and sterilisation was < 24 h. RESULTS: We describe two patients (3 and 6 years old) requiring occipitocervical instrumented fixation for cervical myelopathy secondary to Morquio syndrome with 3D-SSTGs. In the second case, bilateral laminar screw trajectories were also incorporated into the same guide due to the presence of high-riding vertebral arteries. Registration of the postoperative CT to the pre-operative imaging revealed that screws were optimally placed and accurately followed the predefined trajectory. CONCLUSION: To our knowledge, we present the first clinical report of 3D-printed spinal screw trajectory guides at the craniocervical junction in paediatric patients with skeletal dysplasia. The novel combination of multiple trajectories within the same guide provides the intraoperative flexibility of potential bailout options. Future studies will better define the potential of this technology to optimise personalised non-standard screw trajectories.

Patterns of spinal cord malformation in cloacal exstrophy.

OBJECTIVE: The objective of this study was to assess the prevalence and spectrum of spinal dysraphism in a cohort of children with cloacal exstrophy (CEX) using MRI. METHODS: Children with CEX presenting between 1999 and 2019 with baseline spinal MRI were included. The images were reviewed in consensus to assess the type of dysraphism. The dysraphisms were initially reviewed and described based on their descriptive anatomy, and then classified according to anomalies of gastrulation, primary neurulation, or secondary neurulation. RESULTS: Thirty-four children were included. Thirty-three of these children had closed spinal dysraphism, and 1 had a normal spine. Of the 33 cases of closed spinal dysraphism, the conus and/or filum terminale were involved in all cases. The most common malformations were spinal lipoma (n = 20) and terminal myelocystocele (n = 11). The lipomas were heterogeneous: 4 dorsal, 9 transitional, 4 chaotic, and 3 terminal. A large subgroup (10/20, 50%) within the lipomas had an unusual morphology of noncontiguous double lipomas, the proximal fat related to the conus and the distal fat within the filum. These were difficult to characterize using existing classifications. In 2 cases, only a thickened filum was noted. The majority of these malformations were compatible with a disorder of secondary neurulation. CONCLUSIONS: Complex spinal dysraphisms are consistently associated with CEX. The unusual dysraphism patterns found in this group of patients highlight the limitations of current embryological classifications. Given the propensity for neurological deterioration in this group of patients, spinal MRI should be routinely performed. The type and distribution of malformations seen have implications for the wider understanding of the pathogenesis and classification of lumbosacral lipomas.

Vagus nerve stimulation in patients with Lennox-Gastaut syndrome: A meta-analysis.

OBJECTIVES: Lennox-Gastaut syndrome (LGS) is among the most severe epileptic and developmental encephalopathies. A meta-analysis was performed to evaluate the effectiveness of adjunctive vagus nerve stimulation (VNS Therapy) in patients with LGS. MATERIALS & METHODS: PubMed database was queried (January 1997 to September 2018) to identify publications reporting on the efficacy of VNS Therapy in patients with LGS, with or without safety findings. Primary endpoint of the meta-analysis was the proportion of responders (≥50% reduction in seizure frequency). Random-effects analysis was used to calculate weighted mean estimates and confidence intervals. Heterogeneity was evaluated by statistical tests including I2 . RESULTS: Of 2752 citations reviewed, 17 articles (480 patients) were eligible including 10 retrospective studies and seven prospective studies. A random-effects model produced a pooled proportion of 54% (95% confidence intervals [CI]: 45%, 64%) of patients with LGS who responded to adjunctive VNS Therapy (p for heterogeneity <0.001, I2 =72.9%). Per an exploratory analysis, the calculated incidence of serious adverse events associated with VNS Therapy was 9% (95% CI: 5%, 14%); the rate was higher than in long-term efficacy studies of heterogeneous cohorts with drug-resistant epilepsy and likely attributed to variable definitions of serious adverse events across studies. CONCLUSIONS: The meta-analysis of 480 patients with LGS suggests that 54% of patients responded to adjunctive VNS Therapy and that the treatment option was safe and well-tolerated. The response in patients with LGS was comparable to heterogeneous drug-resistant epilepsy populations. A clinical and surgical overview has been included to facilitate the use of VNS in LGS.

Epilepsy surgery in children: what the radiologist needs to know.

This review updates the radiologist on current epilepsy surgery practice in children, with a specific focus on the role of imaging in pre-surgical work-up, current and novel surgical techniques, expected post-surgical imaging appearances and important post-operative complications. A comprehensive review of the current and emerging international practices in paediatric epilepsy surgical planning and post-operative imaging is provided with details on case-based radiological findings. A detailed discussion of the pathophysiology and imaging features of different epileptogenic lesions will not be discussed as this is not the objective of this paper. Epilepsy surgery can be an effective method to control seizures in certain children with drug-resistant focal epilepsy. Early surgery in selected appropriate cases can lead to improved cognitive and developmental outcome. Advances in neurosurgical techniques, imaging and neuroanaesthesia have driven a parallel expansion in the array of epilepsy conditions which are potentially treatable with surgery. The range of surgical options is now wide, including minimally invasive ablative procedures for small lesions such as hypothalamic hamartomata, resections for focal lesions like hippocampal sclerosis and complex disconnective surgeries for multilobar conditions like Sturge Weber Syndrome and diffuse cortical malformations. An awareness of the surgical thinking when planning epilepsy surgery in children, and the practical knowledge of the operative steps involved will promote more accurate radiology reporting of the post-operative scan.

How to obtain diagnostic planes of the fetal central nervous system using three-dimensional ultrasound and a context-preserving rendering technology.

The antenatal evaluation of the fetal central nervous system (CNS) is among the most difficult tasks of prenatal ultrasound (US), requiring technical skills in relation to ultrasound and image acquisition as well as knowledge of CNS anatomy and how this changes with gestation. According to the International Guidelines for fetal neurosonology, the basic assessment of fetal CNS is most frequently performed on the axial planes, whereas the coronal and sagittal planes are required for the multiplanar evaluation of the CNS within the context of fetal neurosonology. It can be even more technically challenging to obtain "nonaxial" views with 2-dimensional (2D) US. The modality of 3-dimensional (3D) US has been suggested as a panacea to overcome the technical difficulties of achieving nonaxial views. The lack of familiarity of most sonologists with the use of 3D US and its related processing techniques may preclude its use even where it could play an important role in complementing antenatal 2D US assessment. Furthermore, once a 3D volume has been acquired, proprietary software allows it to be processed in different ways, leading to multiple ways of displaying and analyzing the same anatomical imaging or plane. These are difficult to learn and time consuming in the absence of specific training. In this article, we describe the key steps for volume acquisition of a 3D US volume, manipulation, and processing with reference to images of the fetal CNS, using a newly developed context-preserving rendering technique.

Ring-enhancing lesions in neonatal meningitis: an analysis of neuroradiology pitfalls through exemplificative cases and a review of the literature.

Very often the clinical course of neonatal meningitis (NM) is characterized by sudden worsening, at times associated with cerebrovascular complications and strokes or the formation of cerebral abscesses. The immediate recognition of these pathological patterns is pivotal in providing clinicians with useful information to differentiate between those different pathological entities, which may both present as ring-enhancing lesions on neuroradiology investigations. Understanding their natural history and diagnostic features is of paramount importance to timely adopt the most appropriate medical and surgical management.