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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.
RESUMO
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.
