Obstructive hydrocephalus from posterior fossa tumor risk factors

Obstructive hydrocephalus from posterior fossa tumor risk factors

Saad et al. from the Emory University Hospital surveyed the CNS (Central Nervous System) Tumor Outcomes Registry at Emory (CTORE) for patients who underwent posterior fossa tumor surgery at 3 tertiary-care centers between 2006 and 2019. Demographic, radiographic, perioperative, and dispositional data were analyzed using univariate and multivariate models.

They included 617 patients undergoing PFT resection for intra-axial (57%) or extra-axial (43%) lesions. Gross total resection was achieved in 62% of resections. Approximately 13% of patients required permanent cerebrospinal fluid shunt. Only 31.5% of patients who required pre- or intraop external ventricular drain (EVD) placement needed permanent cerebrospinal fluid shunt. On logistic regression, Tumor size, transependymal edema, use of perioperative external ventricular drain, postoperative intraventricular hemorrhage (IVH), and surgical complications were predictors of permanent CSF diversion. Preoperative tumor size was the only independent predictor of postoperative shunting in patients with subtotal resection. In patients with intra-axial tumors, transependymal flow (P = .014), postoperative IVH (P = .001), surgical complications (P = .013), and extent of resection (P = .03) predicted need for shunting. In extra-axial tumors, surgical complications were the major predictor (P = .022).

The study demonstrates that the presence of preoperative hydrocephalus in patients with PFT does not necessarily entail the need for permanent CSF diversion. Saad et al. reported the major predictive factors for needing a permanent cerebrospinal fluid shunt for obstructive hydrocephalus 1).

Superior tumor extension (into the aqueduct) and failed total resection of tumor were identified as independent risk factors for postoperative hydrocephalus in patients with fourth ventricle tumor 2).

Cully and colleagues analyzed 117 patients and found the following factors to be associated with a higher incidence of postresection hydrocephalus (PRH): age <3 years, midline tumor location, subtotal resection, prolonged EVD requirement, cadaveric dural grafts, pseudomeningocele formation, and CSF infections 3).

Due-Tonnessen and Hleseth found that patients with medulloblastoma and ependymoma had much higher rates of postoperative shunt placement than astrocytomas 4). Kumar and colleagues in a study of 196 consecutive children found age <3 years, tumor histology of medulloblastoma/ependymoma and partial resections were associated with the increased chances of postresection hydrocephalus 5). A study noted that the only modifiable risk factor for the development of PRH was the presence of intraventricular blood in postoperative imaging 6).

Intraventricular blood can cause hydrocephalus either by the “snow globe effect” 7) or by other factors like impaired absorption of CSF by inflammation and fibrosis of the arachnoid granulations caused by blood degradation products 8).

Gopalakrishnan and colleagues noted the following risk factors for PRH: the need for CSF diversion in the pediatric population—children with symptomatology <3 months duration, severe hydrocephalus at presentation, tumor location in the midline, tumor histology, viz. medulloblastoma and ependymoma, use of intraoperative EVD, longer duration of EVD, postoperative meningitis, and pseudomeningocele 9). Similar findings were also reported by Bognar et al. who showed that the presence of EVD and the duration of EVD were associated with a significant increase in the incidence of postresection CSF diversion. In another recent study, Pitsika et al. 10) showed that patients who underwent EVD had a higher rate of postoperative VPS. They also noted a negative correlation between early EVD clamping and VPS indicating that clamping encourages the re-establishment of normal CSF flow when the obstructive tumor is removed 11). From 12).

Choroid plexus cysts (CPCs) are a type of neuroepithelial cysts, benign lesions located more frequently in the supratentorial compartment. Symptomatic CPCs in the posterior fossa are extremely rare and can be associated with obstructive hydrocephalus

Predictive factors for postoperative hydrocephalus has been identified, including young age (< 3 years), severe symptomatic hydrocephalus at presentation, EVD placement before surgery, FOHR index > 0.46 and Evans index > 0.4, pseudomeningocelecerebrospinal fluid fistula, and infection. The use of a pre-resection cerebrospinal fluid shunt in case of signs and symptoms of hydrocephalus is mandatory, although it resolves in the majority of cases. As reported by several studies included in the present review, we suggest CSF shunt also in case of asymptomatic hydrocephalus, whereas it is not indicated without evidence of ventricular dilatation 13).


Saad H, Bray DP, McMahon JT, Philbrick BD, Dawoud RA, Douglas JM, Adeagbo S, Yarmoska SK, Agam M, Chow J, Pradilla G, Olson JJ, Alawieh A, Hoang K. Permanent cerebrospinal fluid shunt in Adults With Posterior Fossa Tumors: Incidence and Predictors. Neurosurgery. 2021 Nov 18;89(6):987-996. doi: 10.1093/neuros/nyab341. PMID: 34561703; PMCID: PMC8600168.

Chen T, Ren Y, Wang C, Huang B, Lan Z, Liu W, Ju Y, Hui X, Zhang Y. Risk factors for hydrocephalus following fourth ventricle tumor surgery: A retrospective analysis of 121 patients. PLoS One. 2020 Nov 17;15(11):e0241853. doi: 10.1371/journal.pone.0241853. PMID: 33201889; PMCID: PMC7671531.

Cully DJ, Berger MS, Shaw D, Geyer R. An analysis of factors determing the need for ventriculoperitoneal shunts after posterior fossa tumor surgery in children. Neurosurgery 1994;34:402-8.
4) , 8)

Due-Tonnessen B, Helseth E. Management of hydrocephalus in children with posterior fossa tumors: Role of tumor surgery. Pediatr Neurosurg 2007;43:92-6

Kumar V, Phipps K, Harkness W, Hayward RD. Ventriculoperitoneal shunt requirement in children with posterior fossa tumors: An 11-year audit. Br J Neurosurg 1996:10:467-70.

Abraham A, Moorthy RK, Jeyaseelan L, Rajshekhar V. Postoperative intraventricular blood: A new modifiable risk factor for early postoperative symptomatic hydrocephalus in children with posterior fossa tumors. Childs Nerv Syst 2019;35;1137-46.

Tamburrini G, Frassanito P, Bianchi F, Massimi L, Di Rocco C, Caldarelli M. Closure of endoscopic third ventriculostomy after surgery for posterior cranial fossa tumor: The “Snow Globe effect”. Br J Neurosurg 2015;29:386-9.

Gopalakrishnan CV, Dhakoji A, Menon G, Nair S. Factors predicting the need for cerebrospinal fluid diversion following posterior cranial fossa tumor surgery in children. Pediatr Neurosurg 2012;48:93-101

Pitsika M, Fletcher J, Coulter IC, Cowie CJA. A validation study of the modified Canadian preoperative prediction rule for hydrocephalus in children with posterior fossa tumors. J Neurosurg. doi: 10.3171/2021.1.PEDS20887.

Bognar L, Borgulya G, Benke P, Madarassy G. Analysis of CSF shunting procedure requirement in children with posterior fossa tumors. Childs Nerv Syst 2003;19:332-6.

Muthukumar N. Hydrocephalus Associated with Posterior Fossa Tumors: How to Manage Effectively? Neurol India. 2021 Nov-Dec;69(Supplement):S342-S349. doi: 10.4103/0028-3886.332260. PMID: 35102986.

Anania P, Battaglini D, Balestrino A, D’Andrea A, Prior A, Ceraudo M, Rossi DC, Zona G, Fiaschi P. The role of external ventricular drainage for the management of posterior cranial fossa tumours: a systematic review. Neurosurg Rev. 2021 Jun;44(3):1243-1253. doi: 10.1007/s10143-020-01325-z. Epub 2020 Jun 3. PMID: 32494987.

Endoscopic Third Ventriculostomy for Obstructive Hydrocephalus

Endoscopic Third Ventriculostomy for Obstructive Hydrocephalus

Treatment options include endoscopic approaches, which should be individualized to the child. The long-term outcome for children that have received treatment for hydrocephalus varies. Advances in the brain imagingtechnology, and understanding of the pathophysiology should ultimately lead to improved treatment of the disorder. 1).

Age and etiology play a crucial role in the success of endoscopic third ventriculostomy (ETV) as a treatment of obstructive hydrocephalus. The outcome is worse in infants, and controversies still exist whether ETV is superior to shunt placement.

El Damaty et al. retrospectively analyzed 70 patients below 2 years from 4 different centers treated with ETV and assessed success.

Children < 2 years who received an ETV within 1994-2018 were included. Patients were classified according to age and etiology; < 3, 4-12, and 13-24 months, etiologically; aqueductal stenosisposthemorrhagic hydrocephalus (PHH), tumor-related, fourth ventricle outlet obstruction, with Chiari type 2 malformation and following cerebrospinal fluid infection. They investigated statistically the predictors for ETV success through computing Kaplan-Meier estimates using the patient’s follow-up time and time to ETV failure.

They collected 70 patients. ETV success rate was 41.4%. The highest rate was in tumor-related hydrocephalus and fourth ventricle outlet obstruction (62.5%, 60%) and the lowest rate was in Chiari-type II and following infection (16.7%, 0%). The below 3 months age group showed a relatively lower success rate (33.3%) in comparison to older groups which showed similar results (46.4%, 46.6%). Statistically, a previous VP shunt was a predictor for failure (p-value < 0.05).

Factors suggesting a high possibility of failure were age < 3 months and etiology such as Chiari type 2 malformation or following cerebrospinal fluid infection. Altered CSF dynamics in patients with posthemorrhagic hydrocephalus and under-developed arachnoid villi may play a role in ETV failure. They do not recommend ETV as first-line in children < 3 months of age or in case of Chiari II or following infection 2).


A role for endoscopic third ventriculostomy (ETV) in myelomeningocele (MM) has provoked much debate, principally due to anatomical variants described, which may complicate the procedure.

Perez da Rosa et al. present 7 cases of children with MM and hydrocephalus undergoing a total of 10 ETV procedures. All patients demonstrated clinical improvement (in acute/subacute cases) or stabilization (in chronic cases). Three patients requiring a second ETV have shown clinical stability and renewed radiological evidence of functioning ventriculostomies in follow-up since reintervention. ETV can be used, albeit cautiously, in selected cases of hydrocephalus associated with MM. However, the frequency with which anatomical variation is encountered and the difficulty of the assessment of success make the procedure more challenging than usual 3).

Idiopathic normal pressure hydrocephalus

The only randomized trial of endoscopic third ventriculostomy (ETV) for idiopathic normal pressure hydrocephalus (iNPH) compares it to an intervention which is not a standard practice (VP shunting using a non-programmable valve). The evidence from this study is inconclusive and of very low quality. Clinicians should be aware of the limitations of the evidence. There is a need for more robust research on this topic to be able to determine the effectiveness of ETV in patients with iNPH 4).

Endoscopic third ventriculostomy (ETV) provides a physiological restoration of cerebrospinal fluid and a shunt-free option for pediatric hydrocephalus. Continuous developments in techniques and instruments have improved ETV as the first-line treatment.

Endoscopic third ventriculostomy with choroid plexus cauterization (ETV/CPC) offers an alternative to shunt treatment for infantile hydrocephalus.

More patients undergo ETV with a better outcome, identifying a new era of hydrocephalus treatment. Deeper understanding of ETV will improve a better shunt-free survival for pediatric hydrocephalus patients 5).

Hydrocephalus from thalamic hemorrhage

ETV is a safe and effective technique for the management of hydrocephalus resulting from an extraventricular obstruction in ETV is a safe and effective technique for the management of hydrocephalus resulting from an extraventricular obstruction in thalamic hemorrhage. It can avoid the need for permanent shunting in this patient population. Larger studies should be conducted to validate and further analyze this intervention.

It can avoid the need for permanent shunting in this patient population. Larger studies should be conducted to validate and further analyze this intervention 6).



Kahle KT, Kulkarni AV, Limbrick DD Jr, Warf BC. Hydrocephalus in children. Lancet. 2015 Aug 6. pii: S0140-6736(15)60694-8. doi: 10.1016/S0140-6736(15)60694-8. [Epub ahead of print] Review. PubMed PMID: 26256071.

El Damaty A, Marx S, Cohrs G, Vollmer M, Eltanahy A, El Refaee E, Baldauf J, Fleck S, Baechli H, Zohdi A, Synowitz M, Unterberg A, Schroeder HWS. ETV in infancy and childhood below 2 years of age for treatment of hydrocephalus. Childs Nerv Syst. 2020 Mar 28. doi: 10.1007/s00381-020-04585-8. [Epub ahead of print] PubMed PMID: 32222800.

Perez da Rosa S, Millward CP, Chiappa V, Martinez de Leon M, Ibáñez Botella G, Ros López B. Endoscopic Third Ventriculostomy in Children with Myelomeningocele: A Case Series. Pediatr Neurosurg. 2015 May 27. [Epub ahead of print] PubMed PMID: 26021675.

Tudor KI, Tudor M, McCleery J, Car J. Endoscopic third ventriculostomy (ETV) for idiopathic normal pressure hydrocephalus (iNPH). Cochrane Database Syst Rev. 2015 Jul 29;7:CD010033. doi: 10.1002/14651858.CD010033.pub2. Review. PubMed PMID: 26222251.

Feng Z, Li Q, Gu J, Shen W. Update on Endoscopic Third Ventriculostomy in Children. Pediatr Neurosurg. 2018 Aug 15:1-4. doi: 10.1159/000491638. [Epub ahead of print] Review. PubMed PMID: 30110690.

Zeineddine HA, Dono A, Kitagawa R, Savitz SI, Choi HA, Chang TR, Ballester LY, Esquenazi Y. Endoscopic Third Ventriculostomy for Hydrocephalus Secondary to Extraventricular Obstruction in Thalamic Hemorrhage: A Case Series. Oper Neurosurg (Hagerstown). 2020 May 4. pii: opaa094. doi: 10.1093/ons/opaa094. [Epub ahead of print] PubMed PMID: 32365205.

Update: Transient obstructive hydrocephalus


While obstructive hydrocephalus is a relatively common and potentially life-threatening condition, transient obstructive hydrocephalus is a rare condition in adults.


Transient obstruction of cerebrospinal fluid (CSF) flow through the ventricular system has been reported to result from systemic causes such as lead and carbon monoxide poisoning as well as CNS infections and meningitis 1).
Previous case reports have also described spontaneous resolution of obstructive hydrocephalus after intraventricular hemorrhage (IVH) in neonates and adults.
Transient acute hydrocephalus after spontaneous intracranial bleeding in adults 2).
Obstructive hydrocephalus with deterioration of consciousness from a ruptured arteriovenous malformation (AVM) requires urgent decompression, but also vigilance during the preoperative stage in case of rare spontaneous resolution 3).

The acute phase in a cerebellar infarction may become complicated with transient obstructive hydrocephalus, subsequent intracranial hypertension, and the need for surgical management. Although many patients respond well to medical treatment, clinical findings and neuroimaging methods must be considered to determine whether the hydrocephalus can be surgically treated in a timely fashion.
In fourteen patients, six required surgery for hydrocephalus management. Three of the cases had an endoscopic third ventriculostomy without complications, the rest were managed conservatively. As an average, patency was re-established in the aqueduct three months post ictus.
Management of obstructive hydrocephalus in the acute phase of a cerebellar stroke must be individualized. In cases with transient obstructive hydrocephalus, endoscopic third ventriculostomy is a good surgical treatment option that avoids the risks of a long-term ventricular shunt 4).

Case reports


Two cases of transient obstructive hydrocephalus caused by obstruction of mesencephalic duct in patients that presented with altered consciousness which resolved spontaneously in a few hours5).

A 66-year-old male was admitted with sudden onset right-sided hemiparesia. CT demonstrated a hematoma on the left basal ganglia with extension to all ventricles. The following day, the patient’s neurological status progressed to coma and developed bilateral pyramidal signs. MRI demonstrated obstructive hydrocephalus and acute diffuse infarction accompanied by elevation of the CC. On the same day there was improvement in his neurological status with significant decrease in ventricular size and complete resolution of the clot in the third ventricle. The mechanism of signal abnormalities is probably related with the neural compression of the CC against the falx. Presumably, the clot causing obstruction in the third ventricle dissolved or decayed by the help of fibrinolytic activity of CSF, which was raised after IVH and caused spontaneous improvement of hydrocephalus. Bilateral neurological symptoms suggest diffuse axonal damage and normalization of the intracranial pressure should be performed on the early onset of clinical detorioration in order to prevent axonal injury 6).


A 33-year-old man with a previously diagnosed Spetzler-Martin Grade 5 arteriovenous malformation presented with severe headache, which was found to be due to IVH. Forty hours after presentation he developed significant obstructive hydrocephalus due to the thrombus migrating to the cerebral aqueduct, and a ventriculostomy placement was planned. However, shortly thereafter his headache began to improve spontaneously. Within 4 hours after onset the headache had completely resolved, and an interval head CT scan revealed resolution of hydrocephalus.
In patients with IVH, acute obstructive hydrocephalus can develop at any time after the ictus. Though a delayed presentation of acute but transient obstructive hydrocephalus is unusual, it is important to be aware of this scenario and ensure that deterioration secondary to thrombus migration and subsequent obstructive hydrocephalus do not occur 7).

Transient obstructive hydrocephalus following traumatic brain injury 8).


Transient obstructive hydrocephalus by intraventricular fat migration after surgery of the posterior fossa 9).


A 86-year-old man with right frontal stroke developed obstructive hydrocephalus caused by blood in the cerebral aqueduct. The patient had sudden and immediate clinical improvement and a repeated head computed tomography (CT) scan showing spontaneous resolution of hydrocephalus. Spontaneous resolution of obstructive hydrocephalus is possible when the cause is minimal blood in the cerebral aqueduct without any blood in the fourth ventricle 10).


Spontaneous resolution of acute hydrocephalus without aspiration of cerebral fluid is rare. In a neonate born at full term this has only been reported once before. Abubacker et al., report on one further case that was caused by intraventricular haemorrhage (IVH). The probable mechanism is resolution of the acute haemorrhage in the region of the aqueduct, resulting in resolution of the hydrocephalus itself. The importance of considering conservative management of acute hydrocephalus in the clinically stable neonate is emphasised 11).


A 64-year-old woman presented with headache. Computerized tomography (CT) scan revealed hydrocephalus with tiny blood clots in the left foramen of Monro and in the aqueduct. Six hours after the onset, the signs and symptoms disappeared spontaneously. The second CT showed improvement of the hydrocephalus with migration of the clot into the i.v. ventricle. Aqueductal trapping and releasing of the clot formed by bleeding from the choroid plexus located in the left foramen of Monro was suspected for the origin of the transient hydrocephalus 12).


Acute transient hydrocephalus in carbon monoxide poisoning: a case report 13).


In the Sultanate of Oman acute lead encephalopathy in neonates is common. Brain oedema in acute lead encephalopathy occurs predominantly in the cerebellar vermis and may act as a midline posterior fossa mass, occluding the fourth ventricle. The resultant transient obstructive hydrocephalus may need emergency drainage of cerebro-spinal fluid. The hydrocephalus is transient as vermis oedema subsides with medical treatment. Two such cases are reported and discussed 14).


Spontaneous resolution of acute hydrocephalus. A case report 15).


One and a half years old boy was admitted with vomiting and somnolence four days after head injury. The first CT scans taken on admission showed high density areas in the prepontine and ambient cisterns and in the aqueduct. The lateral and third ventricles were dilated, while the fourth ventricle was normal. On the 2nd hospital day he was nearly asymptomatic. The second CT scans done seven days after injury no longer revealed the high density areas and the ventricular dilatation. Vomiting is one of the most important signs for intracranial mass lesions after head injury. But children often vomit even without having mass lesions, and CT scan is useful for evaluation of such cases. In our case, vomiting was probably due to aqueductal obstruction by a small clot resulting acute hydrocephalus, as revealed by CT scans. This case suggested that transient obstructive hydrocephalus must be taken into consideration as one of causes for posttraumatic vomiting 16).

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