Seizures as presentation of shunt malfunction: tertiary paediatric neurosurgery experience.

AIM: Patients with a background of cerebrospinal fluid (CSF)-diverting shunts are frequently investigated for shunt malfunction when presenting with seizures. However, there is very limited evidence in the literature regarding the association of seizures and shunt malfunction. We sought to determine the incidence of shunt malfunction in our cohort of shunted paediatric patients presenting with seizures, and the utility of seizures as a marker of shunt malfunction. METHODS: We retrospectively identified all shunted patients presenting with seizures, as well as all patients undergoing shunt revision following a presentation with seizures from our hospital database over a 14-year period from 2009 to 2023. Data gathered included demographics, de novo seizures or change in pattern of seizures, the aetiology of hydrocephalus and the segment of shunt requiring revision. Exclusion criteria included infected cases requiring shunt externalisation. A literature review of all papers discussing seizures as a presentation of shunt malfunction was also carried out. RESULTS: Overall, over a 14-year period of study, 338 shunted patients presented with seizures and were referred as suspected shunt malfunction with 10 having confirmed shunt malfunction requiring revision (2.9%). This group represented 6.2% of 161 cases of shunt revision carried out during the 14-year period of study. Post-haemorrhagic hydrocephalus secondary to prematurity was the commonest aetiology of shunted hydrocephalus presenting with seizures. Out of 10 patients presenting with seizures with shunt malfunction, 4 presented with de novo seizures, while 6 presented with a change in seizure pattern or frequency in already known epileptic patients. Shunt revision surgeries included 5 distal catheter, 2 proximal catheter, 1 proximal catheter-valve, 1 valve only and 1 case of whole shunt change. CONCLUSION: Our data supports that seizures are rare manifestation of shunt malfunction and can present either de novo or with a change in seizure frequency in already-known epileptic patients.

Dens Growth After Surgical Fixation in Children with Morquio-Brailsford Disease.

Mucopolysaccharidosis type IVA is a lysosomal storage disorder caused by a deficiency of the enzyme N-acetyl-galactosamine-6-sulphate sulphatase. Mucopolysaccharidosis type IVA is multisystemic disease with significant spinal involvement and atlantoaxial instability leading to neural compression and significant morbidity. Dens hypoplasia is a common feature of this condition. In this study we demonstrate that after spinal fixation, there is new growth of dens in significant proportion of patients, suggesting atlantoaxial instability as one of the major driving forces of lack of development of dens in this condition.

Retroflexed dens in paediatric Chiari 1 patients and implications: Single centre retrospective study.

INTRODUCTION: Chiari 1 malformation and hind brain hernia can be associated with skull base and craniocervical anomalies. One of the more recently associated anomalies is a retroverted or retroflexed odontoid process or dens. We conducted a retrospective study of our operated symptomatic and conservatively managed asymptomatic Chiari cohort to assess the impact of dens retroflexion on rate of revision or cerebrospinal fluid diversion following primary foramen magnum decompression (FMD). METHODS: We undertook a retrospective study of all foramen magnum decompression (FMD) cases for Chiari type 1 malformation performed over a 15-year period in a single tertiary paediatric neurosurgical unit. For comparison, non-operated asymptomatic Chiari cases were considered as reference cohort. Information gathered included: demographics, age, sex, length of cerebellar tonsils below McRae's line, pB-C2 distance (a line drawn perpendicular to one drawn between the basion and the posterior aspect of the C2 body), angle of retroflexion (angle formed between a line drawn through the odontoid synchondrosis and its intersection with a line drawn from the tip of the odontoid process) and angle of retroversion (angle formed between the line drawn from the base of C2 and its intersection with a line drawn from the tip of the odontoid process). Grade of retroflexion was measured using pre-operative mid-sagittal MR images and classified as grade 0 (> 90°), grade 1 (85°-89°); grade 2 (80°-84°) and grade 3 (< 80°). The rates for redo surgery or need for cerebrospinal fluid (CSF) diversion were obtained from clinical records and compared in the operated and non-operated groups. RESULTS: One hundred twenty-six Chiari 1 patients were included in this study with adequate imaging. Sixty-five patients were in the non-operated asymptomatic cohort with 61 patients in the operated symptomatic cohort. Mean age of non-operated cohort was 10.2 years with M:F ratio (30:35). Mean cerebellar tonsillar length below McRae's line was 10.3 mm. 7.7% of this cohort had associated syrinx. Mean angles of retroversion and retroflexion were 76 and 78°, respectively. Retroflexion grades included (9.2% grade 1, 35% grade 2 and 52.3% grade 3). pB-C2 distance was 6.8 mm. Mean age of operated cohort was 11.3 years, with M:F ratio (21:40). Mean cerebellar tonsillar length below McRae's line was 15 mm. 45.9% of this cohort had associated syrinx. Mean angles of retroversion and retroflexion were 73 and 74.5°, respectively. Retroflexion grades included (4.9% grade 1, 16.5% grade 2 and 78.6% grade 3). pB-C2 distance was 6.9 mm. No association was identified between retroflexion grade and rate of revision or CSF diversion following primary foramen magnum decompression. CONCLUSION: The operated Chiari 1 cohort had more retroflexed dens, longer tonsils and associated syrinx compared to the non-operated asymptomatic cohort.

Transcallosal approach and post-operative subdural collections: 12-year paediatric neurosurgery tertiary centre experience.

INTRODUCTION: Following transcallosal surgery for tumour resection, the formation of convexity or interhemispheric subdural cerebrospinal fluid collections may lead to clinical deterioration and may influence decision-making with regards to additional interventions. The aim of this study was to determine the incidence, risk factors, and management of subdural collections following the transcallosal approach in a paediatric cohort. METHODS: A retrospective case note and radiological review of all children who underwent transcallosal surgery for intraventricular and thalamic tumours was carried out covering a 12-year period (2012-2023) in a single-centre tertiary paediatric neurosurgery unit. Parameters including demographics and clinical information including lesion location, pathology, extent of resection, need for and type of shunt required, as well as depth, laterality, and location of the collection were analysed prior to shunting, and at approximately 3 weeks, 3 months, and latest follow-up available post-operatively in order to further elucidate the natural history of these subdural collections and their clinical significance. RESULTS: Sixty-four cases satisfied the inclusion criteria of transcallosal surgery for tumour resection; 13 did not have adequate post-operative imaging and were excluded. Of the remaining 51 cases, there were 32 children (63%) with post-operative CSF subdural collections, of which 59% were ipsilateral, with the remainder showing bilateral distribution. The overall shunt insertion rate was 25.5% (12 ventriculoperitoneal and 1 subdural-peritoneal shunt) at 3 months, with a mean time to shunting of 19 days post-operatively. Children who developed post-operative subdural collections had a higher rate of shunting, at 37.5%, compared to 5.2% in those who did not. Pre- and post-operative hydrocephalus and subtotal resection were identified as risk factors for development of subdural collections post-operatively. Subdural collections showed a natural course of reduction and regression over follow-up, with the exception of 3 children where they persisted or increased over time; although none of these required shunting. Those children who underwent shunt insertion showed greater regression in the size of the subdural collection over time compared to the non-shunted group. CONCLUSION: In this paediatric cohort, 25.5 % of children required insertion of a shunt by 3 months following transcallosal surgery. Pre- and post-operative hydrocephalus and subtotal tumour resection were risk factors for development of subdural collections post-operatively.

Anxiety and Depression in Pediatric-Onset Traumatic Spinal Cord Injury: A Systematic Review.

BACKGROUND: Traumatic spinal cord injury (TSCI) is a debilitating neurological condition with significant long-term consequences on the mental health and well-being of affected individuals. We aimed to investigate anxiety and depression in individuals with pediatric-onset TSCI. METHODS: PubMed, Scopus, and Web of Science databases were searched from inception to December 20th, 2022 following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, and studies were included according to the eligibility criteria. RESULTS: A total of 1013 articles were screened, and 18 studies with 4234 individuals were included in the final review. Of these, 1613 individuals (38.1%) had paraplegia, whereas 1658 (39.2%) had tetraplegia. A total of 1831 participants (43.2%) had complete TSCI, whereas 1024 (24.2%) had incomplete TSCI. The most common etiology of TSCI with 1545 people (36.5%) was motor vehicle accidents. The youngest mean age at the time of injury was 5.92 ± 4.92 years, whereas the oldest was 14.6 ± 2.8 years. Patient Health Questionnaire-9 was the most common psychological assessment used in 9 studies (50.0%). Various risk factors, including pain in 4 studies (22.2%), reduced sleep quality, reduced functional independence, illicit drug use, incomplete injury, hospitalization, reduced quality of life, and duration of injury in 2 (11.1%) studies, each, were associated with elevated anxiety and depression. CONCLUSIONS: Different biopsychosocial risk factors contribute to elevated rates of anxiety and depression among individuals with pediatric-onset TSCI. Individuals at risk of developing anxiety and depression should be identified, and targeted support should be provided. Future large-scale studies with long-term follow-up are required to validate and extend these findings.

Intracranial invasive group A streptococcus: a neurosurgical emergency in children.

OBJECTIVE: Invasive group A streptococcus (iGAS) infections are associated with a high rate of morbidity and mortality. CNS involvement is rare, with iGAS accounting for only 0.2%-1% of all childhood bacterial meningitis. In 2022, a significant increase in scarlet fever and iGAS was reported globally with a displacement of serotype, causing a predominance of the emm1.0 subtype. Here, the authors report on iGAS-related suppurative intracranial complications requiring neurosurgical intervention and prolonged antibiotic therapy. METHODS: The authors performed a retrospective chart review of consecutive cases of confirmed GAS in pediatric neurosurgical patients. RESULTS: Five children with a median age of 9 years were treated for intracranial complications of GAS infection over a 2-month period between November 2022 and December 2022. All patients had preceding illnesses, including chicken pox and upper respiratory tract infections. Infections included subdural empyema with associated encephalitis (n = 2), extradural empyema (n = 1), intracranial abscess (n = 1), and diffuse global meningoencephalitis (n = 1). Streptococcus pyogenes was cultured from 4 children, and 2 were of the emm1.0 subtype. Antimicrobial therapy in all patients included a third-generation cephalosporin but varied in adjunctive therapy, often including a toxin synthesis inhibitor antibiotic such as clindamycin. Neurological outcomes varied; 3 patients returned to near neurological baseline, 1 had significant residual neurological deficits, and 1 patient died. CONCLUSIONS: Despite the worldwide increased incidence, intracranial complications remain rarely reported resulting in a lack of awareness of iGAS-related intracranial disease. Awareness of intracranial complications of iGAS and prompt referral to a pediatric neurology/neurosurgical center is crucial to optimize neurological outcomes.

Trapped Fourth Ventricle: Pathophysiology, History and Treatment Strategies.

Trapped fourth ventricle is a clinic-radiological entity characterised by progressive neurological symptoms due to enlargement and dilatation of fourth ventricle secondary to obstruction to its outflow. There are several causative mechanisms for the development of trapped fourth ventricle, including previous haemorrhage, infection or inflammatory processes. However, this condition is most commonly observed in ex preterm paediatric patients shunted for a post-haemorrhagic or post-infective hydrocephalus. Until the introduction of endoscopic aqueductoplasty and stent placement, treatment of trapped fourth ventricle was associated with high rates of reoperation and complications resulting in morbidity. With the advent of new endoscopic techniques, supratentorial and infratentorial approaches for aqueductoplasty and stent insertion have revolutionised the treatment of trapped fourth ventricle. Fourth ventricular fenestration and direct shunting remain viable options in cases where aqueduct anatomy and length of obstruction is not surgically favourable for endoscopic approaches. In this book chapter, we explore the background, historical developments,$ and surgical treatment strategies in the management of this challenging condition.

Interpretation of telemetric intracranial pressure recordings in people with idiopathic intracranial hypertension after shunt implantation.

BACKGROUND: The M.scio telesensor (Aesculap-Miethke, Germany) is a device integrated within a ventriculoperitoneal (VP) shunt for non-invasive measurement of the intracranial pressure (ICP). The purpose of this study was to analyze the telemetric recordings with the M.scio system in shunted patients with idiopathic intracranial hypertension (IIH), in order to determine reference values and assist the interpretation of telemetric data. METHODS: This was a cohort study of consecutive patients with fulminant IIH who underwent primary VP shunt insertion between July 2019 and June 2022. The first telemetric measurements after surgery in the sitting and supine positions were analyzed. Telemetric ICP values, wave morphology, and pulse amplitude were determined for functioning and malfunctioning shunts. RESULTS: Fifty-seven out of 64 patients had available telemetric recordings. The mean ICP was - 3.8 mmHg (standard deviation (SD) = 5.9) in the sitting and 16.4 mmHg (SD = 6.3) in the supine position. The ICP curve demonstrated pulsatility in 49 (86%) patients. A pulsatile curve with mean ICP in the above ranges indicated a functioning shunt, whereas the lack of pulsatility was challenging to interpret. There was a significant positive correlation between ICP versus amplitude, ICP versus body mass index (BMI), and amplitude versus BMI. CONCLUSIONS: This clinical study defined ICP values and curves in IIH patients with a shunt. The results will assist the interpretation of telemetric ICP recordings in clinical decision making. More research is required to model longitudinal recordings and explore the link between telemetric measurements with clinical outcomes.

Spondylodiscitis following ingestion of button battery in an infant-a case-based update.

Button battery ingestion in infants is an increasingly common surgical emergency which can lead to oesophageal perforation, mediastinitis, trachea-oesophageal fistulation, airway compromise and death. One exceedingly rare complication of battery ingestion is discitis and osteomyelitis in the cervical and upper thoracic spine. Diagnosis is normally delayed due to the non-specific presentation, delayed imaging findings and the initial clinical focus on dealing with the immediate, and potentially life-threatening, complications. We describe a case of a 1-year-old girl who presented with haematemesis and an oesophageal injury, secondary to button battery ingestion. Sagittal reconstruction of the CT chest demonstrated a suspicious area of vertebral erosion in the cervicothoracic spine which prompted a further evaluation with MRI demonstrating spondylodiscitis of C7-T2 with vertebral erosion and collapse. The child was successfully treated with long course of antibiotics. We wish to highlight the importance of clinical and radiological spinal assessment in children with button battery ingestion to avoid delayed diagnosis and complications of spinal osteomyelitis.

Endoscopic fenestration of the superior medullary velum for the treatment of a trapped fourth ventricle-technical note.

A trapped fourth ventricle is a clinic-radiological entity characterised by progressive neurological symptoms due to an enlargement of the fourth ventricle secondary to obstruction to its outflow. This condition is most commonly observed in ex-preterm patients shunted for a post-haemorrhagic or post-infective hydrocephalus. Until the introduction of endoscopic aqueductoplasty and stent placement, through a supratentorial or an infratentorial approach, treatment of trapped fourth ventricle entailed high rates of complications, repeated procedures and consequent morbidity. We describe the first case of successful treatment of trapped fourth ventricle by fenestration of superior medullary velum through an infratentorial approach in a 20-month-old child with a functional supratentorial ventriculoperitoneal shunt and an aqueductal anatomy not favourable for stenting. To the best of our knowledge, this is the first reported case of utilisation of this technique in a patient with a trapped fourth ventricle, and we wish to highlight this new alternative approach in cases where conventional aqueductoplasty and stenting may not be feasible.

Molecular subgroup of medulloblastoma: evaluation of contribution to CSF diversion following tumour resection.

INTRODUCTION: Medulloblastoma is the commonest malignant brain tumour in children. Pre-operative hydrocephalus is present in up to 90% of these patients at presentation. Following posterior fossa surgery, despite resolution of fourth ventricular obstruction, a proportion of these children will still require cerebrospinal fluid (CSF) diversion for management of persistent or new hydrocephalus. Various scoring systems have been developed to predict the risk for CSF diversion following posterior fossa surgery. However, no accurate tool exists regarding which pathological subset or group of medulloblastoma patients will require a shunt post-operatively. In this study we investigated the impact of molecular subgroup of medulloblastoma on shunt dependency post-operatively in paediatric patients. METHODS: We undertook a retrospective multi-centre study of children with medulloblastoma who underwent tumour resection. Those with available molecular subgroup were identified. Demographic data and clinical parameters including age, sex, presence of pre-operative hydrocephalus, extent of surgical resection, evidence of metastasis/leptomeningeal disease and need for CSF diversion post-operatively were further analysed. RESULTS: Sixty-nine children with medulloblastoma with available molecular data were identified during the study period with male to female ratio of 1.5:1 (42M:27F). Twelve patients (17.4%) belonged to SHH, 10 (14.5%) Wnt, 19 (27.5%) Group 3 and 15 (21.7%) Group 4; 13 (18.8%) were non-specified Group 3 or 4. A total of 18 (26%) patients had evidence of leptomeningeal disease at presentation (20% of Wnt, 42% of Group 3, 33% of group 4, 23% of group 3/4, and 0% of SHH). Fifteen patients (22%) underwent post-operative ventriculoperitoneal (VP) shunt insertion. No patient in the Wnt group required ventriculoperitoneal (VP) shunt post-operatively in this cohort. Need for shunt was associated with pre-operative hydrocephalus, leptomeningeal disease, with molecular group 3 or 4 demonstrating higher rate of leptomeningeal disease, and pre-operative hydrocephalus. Age, extent of resection and pre-operative EVD were not associated with need for shunt in this cohort. Regression analysis identified only pre-operative hydrocephalus and leptomeningeal disease as independent predictors of need for shunt post-resection in this cohort. CONCLUSION: All patients requiring permanent post-operative VP shunt belonged to non-Wnt groups, particularly group 3 and 4. Although medulloblastoma subgroup does not independently predict need for post-operative shunt, presence of leptomeningeal disease and pre-operative hydrocephalus, and their higher prevalence in group 3 and 4, likely account for observed higher rate of shunting in these groups.

Spinal canal stenosis in children with achondroplasia: the role of augmentation laminoplasty-a 15-year single institution experience.

PURPOSE: Achondroplasia typically results in compressive spinal canal stenosis in one-third of children, but rare under the age of 15 years. Laminectomy is the mainstay of treatment but this leads to instability and progressive deformity requiring complex fixation. In order to reduce that risk, we developed a novel modified augmented laminoplasty that increases spinal canal diameter while preserving the posterior column stability. METHODS: All laminoplasty cases for spinal compressive achondroplasia from 2006 to 2020 were included. Ten augmentation laminoplasty procedures were performed in 7 children with regular clinical and radiological post-operative follow-up. Kyphotic deformity and clinical outcomes (neurological and urological) were evaluated. RESULTS: At presentation, clinical features included radiculopathy, neurogenic claudication or acute cauda equina compression with sphincter dysfunction. The average age at initial surgery was 11.2 (range 5-16) with a mean follow-up of 5 (range 2-8) years. All patients demonstrated improvement in neurogenic claudication symptoms after surgery; however, bladder dysfunction persisted in some children. In one child, cervical and lumbar augmentation laminoplasties were performed for concomitant disease. Augmentation laminoplasty effectively prevented deformity progression over time in all cases except one where a further revision laminoplasty with extension was required for screw loosening. Despite this, progressive symptomatic kyphotic deformity led to a 360° fixation. Minor complications included one dural breach (repaired intraoperatively) and one superficial wound infection. CONCLUSION: Augmentation laminoplasty is a viable surgical option following laminectomy in achondroplasia patients as an alternative to surgical fixation. Fixation can be reserved for cases where there is progressive deformity and kyphosis.

ERF-related craniosynostosis and surgical management in the paediatric cohort.

INTRODUCTION: ERF mutation is one of the most recently identified genetic aberrations associated with syndromic craniosynostosis. Data on the pattern of craniosynostosis, surgical management of ERF-related craniosynostosis and outcomes is limited. We report on our single-centre experience in paediatric cohort of patients with syndromic craniosynostosis secondary to ERF mutation. METHODS: A retrospective review of all paediatric craniofacial cases was performed over an 8-year period (2014-2022). All patients with genetically confirm ERF-related craniosynostosis were identified, and clinical parameters including, age, sex, pattern of craniosynostosis, associated tonsillar herniation and follow-up period were further analysed from electronic clinical and imaging systems. All patients were selected and discussed in multidisciplinary craniofacial meeting (composed of neurosurgical, maxillofacial, plastics and genetics teams) prior to any surgical intervention. RESULTS: Overall, 10 patients with ERF-related craniosynostosis were identified with a male-to-female ratio of 4:1 with mean age at the time of surgery of 21.6 months with a mean follow-up period of 5.2 years. ERF-confirmed cases led to variable craniosynostosis pattern with multi-sutural synostosis with concurrent sagittal and bilateral lambdoid involvement as the most common pattern (7/10). No patient pre-operatively had evidence of papilloedema on ophthalmological assessment. Eight out of 10 patients had associated low-lying tonsils/hind brain hernia pre-operatively. Eight out of 10 patients required surgery which included 2 fronto-orbital advancement, 3 calvarial remodelling, 2 posterior calvarial remodelling/release and 1 insertion of ventriculoperitoneal shunt. CONCLUSION: Involvement of sagittal and lambdoid sutures is the most common pattern of craniosynostosis. ERF-related craniosynostosis can have variable pattern of suture fusion, and management of each patient requires unique surgical planning and execution based on clinical needs for the optimal outcomes.

Myasthenia gravis complicating the surgical management of achondroplasia: a case-based update.

BACKGROUND: Achondroplasia is the commonest skeletal dysplasia of autosomal dominant inheritance caused by "gain of function" mutations in the fibroblast growth factor receptor 3 (FGFR3) gene. Foramen magnum compression due to accelerated ossification and spinal canal stenosis secondary to reduced interpedicular distance is a hallmark of achondroplasia, driven by G380R nucleotide pair substitution. In severe cases, limb weakness and neurogenic claudication will require surgical decompression. Rarely, a neurological condition may mimic the compressive spinal dysfunction and therefore, non-surgical causes must also be considered in cases of acute neurological deterioration in children with achondroplasia. Myasthenia gravis (MG) is an autoimmune condition resulting in fatigable muscle weakness. There are no reported cases of myasthenia gravis in achondroplasia in the literature. RESULTS: We report a child with achondroplasia scheduled for decompressive surgery for severe lumbar canal stenosis presenting with neurological claudication and knee weakness. While waiting for surgery during the COVID-19 pandemic, she developed generalized fatigability and severe weakness raising concerns of acute worsening of cord compression. Urgent investigations ruled out spinal cord compression but identified an unexpected concurrent myasthenia gravis with positive antibodies to acetylcholine receptors. The surgical intervention was postponed averting the potential risk of life-threatening anaesthetic complications. She was successfully managed with a combination of pyridostigmine, steroids, azathioprine, and plasma exchange. CONCLUSION: We report the first case of myasthenia gravis in achondroplasia and review implications in the management.

Tectal Plate Gliomas Masquerading as Idiopathic Aqueduct Stenosis.

Aqueduct stenosis is a recognized cause of obstructive hydrocephalus in children and can be treated effectively with endoscopic third ventriculostomy. Preoperative magnetic resonance imaging is often diagnostic of the cause of aqueduct stenosis. We describe 2 pediatric cases with obstructive hydrocephalus secondary to a working diagnosis of idiopathic aqueduct stenosis. Following successful endoscopic third ventriculostomy, repeat magnetic resonance brain imaging revealed tectal plate glioma as the primary cause of obstruction. We believe these 2 reported cases demonstrate a previously unreported phenomenon whereby concealed tectal gliomas presenting with hydrocephalus are only unmasked following relief of hydrocephalus and decompression and normalization of the ventricular system. We aim to raise awareness about this unusual phenomenon and recommend routine postoperative interval imaging following endoscopic third ventriculostomy to avoid missing underlying pathology masquerading as aqueduct stenosis.

Posterior Calvarial Distraction in older paediatric population: single centre paediatric neurosurgery craniofacial unit outcomes.

PURPOSE: Posterior calvarial distraction (PCD) is a safe and effective technique used to increase cranial vault volume and therefore reduce intracranial pressure in children with complex craniosynostosis. Optimal timing and method used for PCD is controversial. This procedure is usually performed in children younger than 2 years. Literature regarding calvarial distraction in older children is sparse and limited. We report our single-centre experience with PCD in children aged 6 and above to outline the applications, benefits and challenges of employing this technique in an older paediatric population. METHODS: A retrospective analysis of a database on craniofacial cases from 2006 to 2021 was performed. Patients undergoing PCD were identified and children aged 6 and above at the time of operation were included. Data on demographics and clinical outcomes were obtained from electronic records and relevant imaging was reviewed. All cases were reviewed prior to a decision for surgery by the multidisciplinary craniofacial team (composed of neurosurgery, maxillofacial and plastics teams) and underwent surgery in our paediatric craniofacial centre. RESULTS: Overall, 98 PCD cases were identified during the study period, of which 20 cases were identified as having undergone PCD at age 6 or above with mean age of 8.8 years (range 6-18). The most common indication was pansynostosis associated with raised intracranial pressure. Four cases had calvarial remodelling previously and represented with symptoms of raised intracranial pressure sometime after their initial surgery requiring PCD as rescue procedure. Average duration of inpatient stay was 5.85 days. The average duration of follow-up was 3.5 years (0.3 to 11 years). Mean distraction distance achieved was 22.5 mm (18-29 mm). Five patients experienced complications related to wound infection or distractor. Follow-up assessment in all patients demonstrated evidence of vault expansion and symptomatic improvement and resolution of intracranial pressure signs. Comparison with younger cohort did not reveal any difference in any parameters except lower rate of transfusion in the older cohort compared to young cohort (5% vs 38%). CONCLUSION: Posterior calvarial distraction in older children is safe and effective for vault expansion and treatment of raised intracranial pressure in selected cases. A multidisciplinary craniofacial team approach is crucial for appropriate case selection and management in order to optimise outcomes.

UK Chiari 1 Study: protocol for a prospective, observational, multicentre study.

INTRODUCTION: Chiari 1 malformation (CM1) is a structural abnormality of the hindbrain characterised by the descent of the cerebellar tonsils through the foramen magnum. The management of patients with CM1 remains contentious since there are currently no UK or international guidelines for clinicians. We therefore propose a collaborative, prospective, multicentre study on the investigation, management and outcome of CM1 in the UK: the UK Chiari 1 Study (UKC1S). Our primary objective is to determine the health-related quality of life (HRQoL) in patients with a new diagnosis of CM1 managed either conservatively or surgically at 12 months of follow-up. We also aim to: (A) determine HRQoL 12 months following surgery; (B) measure complications 12 months following surgery; (C) determine the natural history of patients with CM1 treated conservatively without surgery; (D) determine the radiological correlates of presenting symptoms, signs and outcomes; and (E) determine the scope and variation within UK practice in referral patterns, patient pathways, investigations and surgical decisions. METHODS AND ANALYSIS: The UKC1S will be a prospective, multicentre and observational study that will follow the British Neurosurgical Trainee Research Collaborative model of collaborative research. Patients will be recruited after attending their first neurosurgical outpatient clinic appointment. Follow-up data will be collected from all patients at 12 months from baseline regardless of whether they are treated surgically or not. A further 12-month postoperative follow-up timepoint will be added for patients treated with decompressive surgery. The study is expected to last three years. ETHICS AND DISSEMINATION: The UKC1S received a favourable ethical opinion from the East Midlands Leicester South Research Ethics Committee (REC reference: 20/EM/0053; IRAS 269739) and the Health Research Authority. The results of the study will be published in peer-reviewed medical journals, presented at scientific conferences, shared with collaborating sites and shared with participant patients if they so wish.