Trigeminal neuralgia (TGN) secondary to hydrocephalus is relatively uncommon in clinical practice. This study aimed to investigate the correlation between hydrocephalus and TGN and evaluate the efficacy of surgical intervention in alleviating TGN. We conducted a retrospective analysis of three cases from our institution and performed a systematic literature review (PubMed search up to December 2024). The inclusion criteria were patients with concurrent hydrocephalus and TGN. Data were analyzed for demographic characteristics, treatment modalities, and outcomes. Among the 21 analyzed cases (including the 3 patients reported in our study), the mean age was 38 years (range: 22-64), with a balanced gender distribution (male-to-female ratio: 11:10). The etiologies included isolated hydrocephalus (n = 12 cases), Chiari I malformation (CIM) (n = 5), Dandy-Walker syndrome (DWS) (n = 2), and tumor-related cases (n = 2). Ventriculoperitoneal shunt (VPS) resulted in complete pain relief in 75% (n = 9/12) of hydrocephalus cases, while endoscopic third ventriculostomy (ETV) was effective in two cases. Microvascular decompression (MVD) showed variable efficacy, with better outcomes when combined with cerebrospinal fluid (CSF) diversion procedures. Hydrocephalus may represent an underrecognized secondary cause of TGN. CSF diversion procedures (VPS/ETV) should be considered as first-line interventions, with MVD reserved for refractory cases. These findings support a multidisciplinary approach to diagnosis and management.

The neurodevelopmental outcome of 'Cystic' malformations of the posterior fossa with marked opening of the fourth ventricle, such as Dandy Walker malformation (DWM) and large Blake's pouch cyst (BPC), is a major issue. This study aimed to refine relevant MRI criteria for distinguishing DWM from BPC and identify prognostic factors. Inclusion criteria were prenatal retrocerebellar fluid space diameter > 10 mm, marked opening of the fourth ventricle with a tegmento-vermian angle (TVA) > 40°, and postnatal follow-up > 2 years. 27 patients were classified as follows: 6 DWM characterized by an overall upward orientation of the tentorium, an open tegmento-tentorial angle (TTA > 78 ) and a high TVA (median 132°); 15 BPC with a normal downward orientation of the proximal part of the tentorium (TTA < 68°) and distal upward displacement (median TVA 74°); 3 PHACE syndromes (Posterior fossa abnormalities, Haemangioma, Arterial cerebrovascular anomalies, Cardiac defects, Eye anomalies) and 3 unclassified. Four prognostic factors were identified, (i) diagnosis: DWM (two deaths, three learning disabilities and one typical development (TD)) versus BPC (five learning disabilities [4/5 with associated malformation or genetic defects] and 10 TD); (ii) associated versus isolated (36% vs. 87% TD); (iii) obstructive ventriculomegaly versus no hydraulic complications (20% vs. 91% TD); and (iv) the foetal TVA value and clinical outcome (correlation coefficient = 0.561, p = 0.006).

Ventriculoperitoneal shunt placement is the most commonly used treatment for hydrocephalus. However, its malfunction frequently presents a challenge in clinical practice, necessitating shunt revision. In certain instances, intracranial catheter revision may pose difficulties due to severe intraluminal adhesions, necessitating the surgeon to leave the catheter in situ. However, retained catheters can lead to severe complications. A 17-year-old male presented with headache and unsteady gait for several weeks. He had a cystoperitoneal shunt for hydrocephalus associated with Dandy-Walker malformation during infancy. However, at the age of 12 years, the shunt was found to be nonfunctioning and was removed, except for the intradural catheter, due to severe adhesions. Brain MRI revealed a large mass encasing the catheter. Craniotomy and gross-total resection of the mass, including the catheter, revealed a granuloma, but no organisms were isolated from the specimen. The postoperative recovery was uneventful, and there was no recurrence for 10 years. This case highlights a potential complication associated with retained intracranial catheters and their neurosurgical management. Our literature review identified a limited number of comparable cases of retained catheter-related granuloma, and the pathophysiology and treatment were elucidated within the review. https://thejns.org/doi/10.3171/CASE25557.

To report the outcomes of apparently isolated fetal posterior fossa anomalies diagnosed prenatally. MEDLINE, EMBASE and Cochrane databases were searched from inception to 1 September 2024. The inclusion criteria were studies reporting the outcomes of fetuses with a prenatal diagnosis of apparently isolated posterior fossa anomaly, defined as an anomaly with no associated cerebral or extracerebral malformations at the time of the primary diagnosis, including mega cisterna magna (MCM), Blake's pouch cyst (BPC), Dandy-Walker malformation (DWM) and vermian hypoplasia (VH). The outcomes observed were: chromosomal or genetic anomalies; associated structural anomalies detected exclusively on follow-up ultrasound, fetal magnetic resonance imaging (MRI) or postnatal imaging; and adverse neurodevelopmental outcome. Random-effects meta-analyses of proportions were used to combine data. Thirty-one studies (including 676 fetuses with an apparently isolated posterior fossa anomaly and a known outcome) were included. In fetuses with a prenatal diagnosis of isolated MCM, there were no cases of chromosomal anomaly detected on G-banded karyotype analysis, copy number variants (CNVs) detected on chromosomal microarray analysis (CMA), anomalies detected on next generation sequencing (NGS), or associated structural anomalies detected on follow-up ultrasound or fetal MRI, while additional anomalies not detected on prenatal imaging were identified exclusively postnatally in 3.5% (95% CI, 0.7-8.3%) of cases. An abnormal neurodevelopmental outcome was reported in 4.9% (95% CI, 1.5-10.0%) of cases. In fetuses with a prenatal diagnosis of isolated BPC, chromosomal anomaly was reported in 2.7% (95% CI, 0.8-5.4%) of cases and CNVs detected on CMA were reported in 2.9% (95% CI, 0.5-7.0%), while there were no cases of genetic anomaly detected on NGS. There were no cases of additional anomalies detected exclusively on fetal MRI, while on postnatal imaging, 3.2% (95% CI, 0.8-7.1%) of fetuses with a prenatal diagnosis of BPC had an anomaly that was not detected prenatally. In-utero resolution of the cyst was reported in 42.7% (95% CI, 35.7-49.8%) of cases. An abnormal neurodevelopmental outcome was reported in 2.0% (95% CI, 0.5-4.5%) of cases. In fetuses with a prenatal diagnosis of isolated DWM, a chromosomal anomaly was detected in 10.7% (95% CI, 5.4-17.5%) of cases, CNVs were detected on CMA in 15.4% (95% CI, 6.2-27.8%) of cases and genetic anomalies were detected on NGS in 16.5% (95% CI, 4.6-33.8%) of cases. Associated structural anomalies detected exclusively on follow-up ultrasound and fetal MRI were reported in 8.2% (95% CI, 0.2-25.6%) and 17.3% (95% CI, 1.3-45.6%) of cases, respectively, while 11.3% (95% CI, 2.4-25.7%) of fetuses had associated structural anomalies detected only on postnatal imaging. Abnormal neurodevelopmental outcome affected 45.5% (95% CI, 17.3-75.4%) of cases. In fetuses with a prenatal diagnosis of isolated VH, a chromosomal anomaly was reported in 6.0% (95% CI, 0.7-15.9%) of cases, CNVs were detected on CMA in 15.4% (95% CI, 1.0-42.1%) of cases and genetic anomalies were detected on NGS in 17.2% (95% CI, 3.3-38.9%) of cases. There were no cases presenting with associated structural anomalies detected exclusively on follow-up ultrasound or fetal MRI, while 18.1% (95% CI, 5.4-36.0%) of cases had associated structural anomalies detected only on postnatal imaging. An abnormal neurodevelopmental outcome was reported in 23.6% (95% CI, 5.0-50.4%) of cases. There are still significant weaknesses in the current literature on fetal posterior fossa anomalies, mainly characterized by the lack of standardized tools for neurodevelopmental assessment and the heterogeneity in timing of follow-up for most included studies. Fetuses with a prenatal diagnosis of isolated MCM or isolated BPC have a generally favorable outcome. Conversely, DWM is associated with a significant risk of genetic anomaly and adverse neurodevelopmental outcome, while the small number of cases with VH still precludes an objective evaluation of the actual burden of neurodevelopmental delay in these children. © 2025 International Society of Ultrasound in Obstetrics and Gynecology.

The primary aim of this study was to estimate the incidence of posterior fossa anomalies (PFA) and assess the associated outcomes in King Abdulaziz Medical City (KAMC), Riyadh. All fetuses diagnosed by prenatal ultrasound with PFA from 2017 to 2021 in KAMC were analyzed retrospectively. PFA included Dandy-Walker malformation (DWM), mega cisterna magna (MCM), Blake's pouch cyst (BPC), and isolated vermian hypoplasia (VH). The 65 cases of PFA were 41.5% DWM, 46.2% MCM, 10.8% VH, and 1.5% BPC. The annual incidence rates were 2.48, 2.64, 4.41, 8.75, and 1.71 per 1000 anatomy scans for 2017, 2018, 2019, 2020, and 2021, respectively. Infants with DWM appeared to have a higher proportion of associated central nervous system (CNS) abnormalities (70.4% vs. 39.5%; p-value = 0.014) and seizures than others (45% vs. 17.9%; p-value = 0.041). Ten patients with abnormal genetic testing showed a single gene mutation causing CNS abnormalities, including a pathogenic variant in MPL, C5orf42, ISPD, PDHA1, PNPLA8, JAM3, COL18A1, and a variant of uncertain significance in the PNPLA8 gene. Our result showed that the most common PFA is DWM and MCM. The autosomal recessive pathogenic mutation is the major cause of genetic disease in Saudi patients diagnosed with PFA.