Hydrocephalus Resolution with Third Ventriculostomy with Floor Stenting: Technical Note and Literature Review

Abstract

Introduction: The management of refractory obstructive hydrocephalus is a paramount neurosurgical challenge. The endoscopic third ventriculostomy (ETV) has been accepted as the procedure of choice for obstructive hydrocephalus, depending on the presence of certain risk factors, such as intracranial infections, young age, previous shunt failure and distorted anatomy of the ventricular floor, that predispose occlusion or obstruction of the CSF outflow through the stoma. Case Report: A 20-year-old man with obstructive hydrocephalus due to primary aqueductal stenosis performed several neurosurgical procedures, including two previous ETV, without long term resolution. We performed another ETV, with stent placement at the stoma to prevent occlusion. After 25 months of asymptomatic follow-up, the patient presented with an enlarged fourth ventricle, and a new neuroendoscopic procedure showed a patent stoma and a well-placed stent. Discussion: Stent placement on the third ventricular floor was already reported 19 times in the literature. Its success rate is about 94,7%, and complications happened in 2 cases, with functional impaired in only one of them. Conclusion: Third ventriculostomy with floor stenting proved to be an effective procedure in our case of complex hydrocephalus. It is a viable option in cases where there is a greater chance of stoma occlusion.

Introduction

The management of refractory obstructive hydrocephalus corresponds to a paramount neurosurgical challenge.

The endoscopic third ventriculostomy (ETV) has been accepted as the procedure of choice for obstructive hydrocephalus, although its efficacy rates range between 23% and 93% depending on the operative case selection [1, 2, 3, 4, 5].

The risk of failure increases with intracranial infections, young age, previous shunt failure and distorted anatomy of the ventricular floor [3, 6, 7, 8].

The use of a stent in the third ventricular floor following ETV (stented ETV-sETV) to secure a stoma in the presence of such features has been reported in aqueduct stenosis due to tumorous occlusion, tumorous infiltration of the third ventricular floor or primary aqueductal stenosis [6, 9].

Herein we report a case of refractory obstructive hydrocephalus in which a sETV was safe and effective, after several previous unsuccessful neurosurgical approaches.

Case Report

Clinical Case

A 20-year-old man with obstructive hydrocephalus due to primary aqueductal stenosis performed his first ventriculoperitoneal shunt (VPS) at six months of life.

Due to various complications (such as infections, functional and mechanical shunt failures), several neurosurgical procedures were necessary, including twelve cerebrospinal fluid (CSF) shunts (ten ventriculoperitoneal, one ventriculoatrial, and one ventriculopleural) and two ETV in the last two years alone.

In this period, he also developed two episodes of meningitis and ventriculitis with loculated ventricles. The benefits of the procedures did not last overtime, with both ETV failing within less than two months.

A new ETV was performed, with clinical improvement lasting during five months, when once again hydrocephalus symptoms recurred. A CT-scan and a magnetic resonance (MRI) revealed a non-communicating hydrocephalus, with VPS malfunction and ETV stoma occlusion.

Another ETV was scheduled, and due to presence of several risk factors for ETV failure, we decided to assure the patency of the stoma with the help of a stent.

Procedure (Technical Development)

A rigid neuroendoscope was introduced into the right lateral ventricle through a coronal burr hole, 2cm from the midline.

The foramen of Monro was located with identification of the choroid plexus, and the septal and thalamostriate veins, and the endoscope was passed into the third ventricle.

Neuroendoscopy confirmed a strict local fibrosis (Figure 1A) and a third ventriculostomy was performed, widening the stoma with a 4-French Fogarty catheter and inflating the balloon in front of the division of the basilar artery, between the mamillary bodies and infundibular recess (Figure 1B, 1C).

Figure 1.

A Neuroendoscopic vision of the third ventricle, demonstrating fibrosis on the third ventricular floor. 1. B A 4-French Fogarty catheter inserted to perform the third ventriculostomy. 1. C Fenestration communicating the third ventricle and the interpeduncular cistern (arrow). 2. D Stent placement in the third ventricular floor (arrow). 2. E Stent expanded into the stoma in the floor of the third ventricle, inflating the balloon. 2. F Final stent position (arrow). 2. G, H and I 24 months follow-up neuroendoscopic view of the third ventricle disclosing the adequate positioning of the stent (arrow) and the stoma patency (arrow).

An express 4.5mm x 8.0mm stent enrolling a deflated balloon (Express Biliary LD Pre-mounted Stent System-Boston Scientific Corporation, Natick, MA, USA) was then conducted inside the neuroendoscope through the ventricular system into the stoma (Figure 1D).

The technique was done without any microguide wire.

The stent was then successfully expanded into the stoma in the floor of the third ventricle (Figure 1E) and released at 8 atmospheres of pressure, communicating the third ventricle with the interpeduncular cistern (Figure 1F).

The malfunctioning VPS was removed at the end of the procedure.

Results

Immediate patency of the fenestration was demonstrated under endoscopic visualization of the CSF flow from the third ventricle to the perpendicular cistern.

The postoperative period was uneventful and the patient remained asymptomatic for 25 months.

At this time, he was readmitted with severe gait disturbances and impaired consciousness level.

An MRI displayed a membrane obstructing the proximal portion of the cerebral aqueduct (Figure 2A) with an enlarged, trapped fourth ventricle and showed the stent in the third ventricular floor between the third ventricle and the interpeduncular cistern (Figure 2B).

Figure 2.

A Sagittal T2-weighted MRI revealing the stent communicating the third ventricle and the interpeduncular cistern. (arrow) and the presence of a narrow aqueduct (arrowhead). 2. B Axial T2-weighted MRI demonstrating an enlarged fourth ventricle (arrow).

After a week, another neuroendoscopic procedure was performed and demonstrated proper positioning of the stent with partial involvement by brain tissue, and a patent stoma (Figure 1G, 1H and 1I).

The membrane obstructing the cerebral aqueduct was opened with the neuroendoscope, restoring the physiological CSF circulation and a uniform hydrostatic pressure regimen, and a stent was placed in the aqueduct.

The patient was discharged two days after the procedure for close follow-up on an outpatient basis.

We recently contacted the patient's family members and received information that he was admitted to another neurosurgery service in 2018, due to septicemia and meningitis, and died during treatment.

A new ventriculoscopy was not performed to verify stent patency, however, the patient remained symptom free for an additional 10 years since his last neuroendoscopic procedure.

The authors certify that they have obtained all appropriate patient consent forms before the beginning of the article’s production.

Discussions

Currently, ETV is the treatment of choice in many cases of non-communicating hydrocephalus, with efficacy ranging between 23 and 93%, depending on the cause of hydrocephalus, population, and failure definitions [1, 2, 3, 4, 5].

It acts through two main mechanisms: providing an alternative route for the CSF, diverting the flow from the obstructed region to the new passage created; and increasing ventricular compliance, restoring communication between the ventricles and the cranial and spinal subarachnoid spaces [4, 5].

The main predictors of failure are young age, previous intracranial infection, unfavorable anatomy of the third ventricle floor and previous VPS [3, 6, 7, 8].

These and other factors must be considered when choosing between an ETV or a permanent ventricular shunt. ETV is associated with fewer complications, especially infections, equipment failure (catheter rupture, valve blockage) and the need for reintervention, thus being preferable in most patients.

These advantages are mainly due to the absence of foreign body implantation and the restoration of a physiological circulation of the CSF [1, 2, 3, 4, 8].

In the pediatric population, ETV proved to be more effective in the short and long term in the study published by Ribaupierre et al. [10]; however, reviews of studies comparing VPS and ETV in patients with non-communicating hydrocephalus showed no differences in efficacy between the two [1, 2, 4, 8].

In addition, secondary ETV is an efficient “rescue” technique, both after failure of previous VPS and previous ETV, as demonstrated by Shaikh et al. [3] series and literature review.

It is noteworthy that in patients with VPS infection, secondary ETV is less effective [3, 7].

ETV fails when there is occlusion or obstruction to outflow through the stoma, usually caused by tissue fibrosis at the opening site or by proliferation of arachnoid membranes close to the orifice, respectively [3, 4, 6, 11].

Another major cause of ETV failure is the presence of a communicating hydrocephalus component associated with CSF obstruction, which makes the diversion of CSF flow insufficient to treat the disease [8].

The stoma can be visualized and its opening measured and outflow through the ventriculostomy stoma can be evaluated by MRI, which helps to differentiate the mechanism of failure, should it occur, aiding management [3].

Stented third ventriculostomy

The association of ETV with the implantation of a stent in the floor of the third ventricle (sETV) seeks to prevent stoma occlusion, stabilizing the opening and creating a barrier to the proliferation of fibrous tissue at the site, increasing its long-term patency rate.

However, there is concern that the insertion of a foreign body into the intraventricular and subarachnoid spaces may increase the number of complications, especially the number of infections.

Schulz et al. [6] and Marx et al. [9] have already reported its use in the past, with promising results.

Furthermore, Pitskhelauri et al. [11] reported 9 microsurgical third ventriculostomies with stenting, all associated with fenestration of the interventricular septum.

Thus, in total, 10 cases of sETV were found in our literature review, and adding the microsurgical cases, a total of 19 third ventriculostomies with stenting were reported, our case being the 20th to be published.

Table 1 summarizes every case described so far.

Table 1.

. Reported cases of third ventriculostomies with third ventricular floor stenting, published up to July of 2023.

Case / Author and year of publication	Age (years) / sex	Etiology of hydrocephalus / Third ventricle floor involvement	Previous interven- tions	Procedure route / Stent / Stent position	Follow-up period	Complications and outcome
1 / Pitskhelauri, 2012	20 / M	AS secondary to GB / Present	None	Microsurgery / Silicon ventricular drain fragment / Superior wall of the lateral ventricle to the prepontine cistern	12 months	Transient left-side hemiparesis. Relief of ICP related symptoms. No further surgeries required due to hydrocephalus. Death due to tumor progression.
2 / Pitskhelauri, 2012	20 / F	AS secondary to PA / Present	None	Microsurgery / Silicon ventricular drain fragment / Superior wall of the lateral ventricle to the prepontine cistern	37 months	Relief of ICP related symptoms. No further surgeries required due to hydrocephalus.
3 / Pitskhelauri, 2012	32 / F	AS secondary to tumor + Adhesions at the level of Monro foramen / No involvement	None	Microsurgery / Silicon ventricular drain fragment / Superior wall of the lateral ventricle to the prepontine cistern	22 months	Relief of ICP related symptoms. No further surgeries required due to hydrocephalus. Dislocation of the proximal tip of the stent into the posterior horn of the lateral ventricle, without functional compromise.
4 / Pitskhelauri, 2012	30 / M	AS secondary to GB / Present	None	Microsurgery / Silicon ventricular drain fragment / Superior wall of the lateral ventricle to the prepontine cistern	6 months	Left-side hemiparesis and speech disturbances. Relief of ICP related symptoms. No further surgeries required due to hydrocephalus. Death due to tumor progression.
5 / Pitskhelauri, 2012	23 / M	AS secondary to germinoma / Present	None	Microsurgery / Silicon ventricular drain fragment / Superior wall of the lateral ventricle to the prepontine cistern	6 months	Relief of ICP related symptoms. No further surgeries required due to hydrocephalus.
6 / Pitskhelauri, 2012	18 / M	AS secondary to GB / Present	None	Microsurgery / Silicon ventricular drain fragment / Superior wall of the lateral ventricle to the prepontine cistern	3 months	Transient right-side hemiparesis. Relief of ICP related symptoms. No further surgeries required due to hydrocephalus. Pneumonia, deep vein thrombosis and death due to tumor progression.
7 / Pitskhelauri, 2012	61 / M	AS secondary to GB / Present	None	Microsurgery / Silicon ventricular drain fragment / Superior wall of the lateral ventricle to the prepontine cistern	4 months	Relief of ICP related symptoms. No further surgeries required due to hydrocephalus.
8 / Pitskhelauri, 2012	54 / M	AS secondary to GB / Present	None	Microsurgery / Silicon ventricular drain fragment / Superior wall of the lateral ventricle to the prepontine cistern	7 months	Relief of ICP related symptoms. No further surgeries required due to hydrocephalus. Death due to tumor progression.
9 / Pitskhelauri, 2012	31 / F	AS secondary to PA / No involvement	None	Microsurgery / Silicon ventricular drain fragment / Superior wall of the lateral ventricle to the prepontine cistern	4 months	Relief of ICP related symptoms. No further surgeries required due to hydrocephalus.
10 / Schulz, 2015	0.1 / F	Primary AS / No involvement	None	Endoscopy / 6-hole ventricular drain catheter fragment / Lateral ventricle to the prepontine cistern	16 months	Symptoms remained unchanged. Failure of sETV due to arachnoid proliferations at the tip of the stent and stent migration (tip was inside the third ventricle). New ETV, also resulting in failure. Placement of a VPS, with good results.
11 / Schulz, 2015	1 / M	AS with multiple hamartomas / Present	None	Endoscopy / 6-hole ventricular drain catheter fragment / Lateral ventricle to the prepontine cistern	21 months	Improvement, but not resolution, of ICP related symptoms. No further surgeries required due to hydrocephalus.
12 / Schulz, 2015	8 / F	AS secondary to AA / Present	None	Endoscopy / 6-hole ventricular drain catheter fragment / Lateral ventricle to the prepontine cistern	6 months	Resolution of ICP related symptoms. No further surgeries required due to hydrocephalus.
13 / Schulz, 2015	10 / M	AS with multiple hamartomas and neurofibromatosis type 1 / Present	None	Endoscopy / 6-hole ventricular drain catheter fragment / Lateral ventricle to the prepontine cistern	67 months	Resolution of ICP related symptoms. No further surgeries required due to hydrocephalus.
14 / Schulz, 2015	12 / F	AS secondary to diffuse astrocytoma / Present	VPS	Endoscopy / 6-hole ventricular drain catheter fragment / Lateral ventricle to the prepontine cistern	43 months	Resolution of ICP related symptoms. No further surgeries required due to hydrocephalus.
15 / Schulz, 2015	16 / F	AS secondary to bilocular germ cell tumor / Present	None	Endoscopy / 6-hole ventricular drain catheter fragment / Lateral ventricle to the prepontine cistern	15 months	Resolution of ICP related symptoms. No further surgeries required due to hydrocephalus.
16 / Schulz, 2015	17 / F	AS secondary to intraventricular craniopharyngioma / Present	None	Endoscopy / 6-hole ventricular drain catheter fragment / Lateral ventricle to the prepontine cistern	20 months	Resolution of ICP related symptoms. No further surgeries required due to hydrocephalus.
17 / Schulz, 2015	18 / M	AS secondary to PA / Present	ETV	Endoscopy / 6-hole ventricular drain catheter fragment / Lateral ventricle to the prepontine cistern	18 months	Resolution of ICP related symptoms. No further surgeries required due to hydrocephalus.
18 / Schulz, 2015	25 / F	Primary AS / No involvement	ETV	Endoscopy / 6-hole ventricular drain catheter fragment / Lateral ventricle to the prepontine cistern	3 months	Resolution of ICP related symptoms. No further surgeries required due to hydrocephalus.
19 / Marx, 2016	26 / F	AS secondary to carcinomatous meningitis / NR	NR	Endoscopy / Flat stent / NR	0 months	NR.
20 / present case	20 / M	Primary AS / No involvement	12 CSF shunts 3 ETVs 1 aqueducto- plasty	Endoscopy / Express 4.5mm x 8.0mm stent enrolling a deflated balloon / Third ventricle to the prepeduncular cistern	25 months (symptom free through 12 years)	Resolution of ICP related symptoms for 24 months. New onset hydrocephalus at 25 months (enlarged 4º ventricle) after new cerebral aqueduct obstruction. Neuroendoscopy at the time showed a patent stoma and a well-positioned stent.

Note: Abbreviations: AA=anaplastic astrocytoma; AS=aqueductal stenosis; CSF=cerebrospinal fluid; ETV=endoscopic third ventriculostomy; F=female; GB=glioblastoma; ICP=intracranial pressure; M=male; MRI=magnetic resonance imaging; NR=not reported; PA=pilocytic astrocytoma; sETV=stented endoscopic third ventriculostomy; VPS=ventriculoperitoneal shunt.

We are not aware of previous use of a stent in the floor of the third ventricle for the treatment of a ventriculitis complication.

In almost all reported cases (18 out of 20), stent support was sought because of the presence of factors that predict worse effectiveness of conventional ETV.

Tumor invasion of the floor of the third ventricle was present in 14 of the 20 cases, and its presence or absence was not reported in the case of Marx et al. [9].

Previous procedure failures occurred in 3 of 20 patients, including ours, who underwent 16 procedures before sETV; patient 14 had a previous VPS, which was removed by his own will and not due to complications.

Prior intracranial infections were reported only in our case, but patient 19 also had meningeal involvement (meningeal carcinomatosis).

In addition, patient 10 was very young (1 month), therefore, sETV was performed.

In cases 3 and 9, the intraventricular stent was used due to the involvement of the foramen of Monro and not because of a greater chance of occlusion of the stoma.

sETV proved to be an effective procedure, with good control of hydrocephalus in 18 of the 19 patients with a follow-up period of more than 3 months, generating an efficacy of 94.7%. The mean follow-up time was 19 months, and considering that approximately 95% of ETV failures occur within the first month5, the efficacy rate found would likely remain stable if follow-up was extended.

Schulz et al. [6] reported the only failure of a sETV. This occurred in patient 10, due to CSF outflow blockage by the presence of arachnoid proliferations in the stoma and stent tip, in addition to migration of the stent distal tip into the third ventricle.

This patient required 2 reinterventions, with placement of a VPS that was successful in controlling the hydrocephalus.

Complications related to sETV were observed in only 2 cases (3 and 10), one microsurgical and the other endoscopic.

Stent migration proved to be the most common complication, present in 2 of the 20 cases (10%), but clinical repercussions occurred only in case 10, where there was also occlusion of the stoma, as described above.

Stoma occlusion due to arachnoid proliferations is a common cause of ETV failure in childhood [1, 6], and sETV has not been shown to be able to prevent it, as it occurred in 1 of 2 patients younger than 1.5 years.

Stent migration can be prevented by fixation techniques, with subcutaneous reservoir fixation at the burr-hole site being the most used in intraventricular stents [9].

However, this may not be enough in children, since the head growth can cause the displacement of the distal portion of the stent [6], as occurred in case 10.

In our case, there was no stent fixation, and the use of a stent of metal proved to be effective, as it was surrounded by brain tissue, having its position secured (Figs. 2G, 2H and 2I).

The remaining complications were attributed to the underlying disease or another event.

No infectious complications were observed, although there was fear that the implantation of a foreign body within the CSF system would raise their incidence.

It is hypothesized that this is due to the fact that the stent is completely within the intradural and subarachnoid space [11].

Our patient developed meningitis 12 years after the last neurosurgical intervention.

It is not known, however, whether the stent is involved in the infection, or whether the infection was secondary only to hematogenous spread.

It is noteworthy that antibiotic prophylaxis was used in 19 of the 20 cases, ours included.

Some differences between our case and the literature can be pointed out.

The positioning of the stent used in our case was different from the others, as well as the stent used.

In the 18 cases where the materials and positioning were described, a ventricular drain fragment was used as a stent; they were placed from the lateral ventricle, crossing the Monro foramen and the stoma with its distal portion inside the prepontine cistern.

In our case, a 4.5mm x 8.0mm stent enrolling a deflated balloon was positioned through the stoma from the third ventricle into the interpeduncular cistern.

However, there is no way to compare the techniques with the information available.

The patency of the stoma in our case was confirmed by a new neuroendoscopy performed 25 months after implantation.

Third ventriculostomy with floor stenting proved to be effective in the few cases reported in the literature, including our own, with a success rate of 94.7%.

Stent migration was a common complication (10%), and stoma occlusion occurred in 5%.

Two of the 3 complications occurred in a 1-month-old child, which may indicate that the technique is not a good option in the younger population.

Even with the absence of infectious complications, we recommend the use of perioperative antibiotic prophylaxis.

Therefore, although not recommended as a first-line procedure, sETV should be considered as a viable fallback option in complex hydrocephalus patients, especially in those with risk factors for stoma occlusion.

More studies are needed to confirm the findings present in the literature today and to pinpoint the role of sETV in complex and non-complex hydrocephalus patients.

Conflict of interests

None to declare.