Endoscopic third ventriculostomy as adjunctive therapy in the treatment of low-pressure hydrocephalus in adults

Pathogenesis and management of low-pressure hydrocephalus: A narrative review

Patients diagnosed with low-pressure hydrocephalus typically present with enlarged ventricles and unusually low intracranial pressure, often measuring below 5 cmH2O or even below atmospheric pressure. This atypical presentation often leads to low recognition and diagnostic rates. The development of low-pressure hydrocephalus is believed to be associated with a decrease in the viscoelasticity of brain tissue or separation between the ventricular and subarachnoid spaces. Risk factors for low-pressure hydrocephalus include subarachnoid hemorrhage, aqueduct stenosis, prior cranial radiotherapy， ventricular shunting, and cerebrospinal fluid leaks. For potential low-pressure hydrocephalus, diagnostic criteria include neurological symptoms related to hydrocephalus, an Evans index >0.3 on imaging, ICP ≤ 5 cm H2O, symptom improvement with negative pressure drainage, and exclusion of ventriculomegaly caused by neurodegenerative diseases. The pathogenesis and pathophysiological features of low-pressure hydrocephalus differ significantly from other types of hydrocephalus, making it challenging to restore normal ventricular morphology through conventional drainage methods. The primary treatment options for low-pressure hydrocephalus involve negative pressure drainage and third ventriculostomy. With appropriate treatment, most patients can regain their previous neurological function. However, in most cases, permanent shunt surgery is still necessary. Low-pressure hydrocephalus is a rare condition with a high rate of underdiagnosis and mortality. Early identification and appropriate intervention are crucial in reducing complications and improving prognosis.

Low- and Negative-Pressure Hydrocephalus: New Report of Six Cases and Literature Review

Low- or very-low-pressure hydrocephalus is a serious and rare phenomenon, which is becoming better known since it was first described in 1994 by Pang and Altschuler. Forced drainage at negative pressures can, in most cases, restore the ventricles to their original size, thus achieving neurological recovery. We present six new cases that suffered this syndrome from 2015 to 2020: two of them after medulloblastoma surgery; a third one as a consequence of a severe head trauma that required bifrontal craniectomy; another one after craniopharyngioma surgery; a fifth one with leptomeningeal glioneuronal tumor; and, finally, a patient with a shunt for normotensive hydrocephalus. Before the development of this condition, four of them had mid-low-pressure cerebrospinal fluid (CSF) shunts. Four patients required cerebrospinal fluid (CSF) drainage at negative pressures oscillating from zero to -15 mmHg by external ventricular drainage until ventricular size normalized, followed by the placement of a new definitive low-pressure shunt, one of them to the right atrium. The duration of drainage in negative pressures through external ventricular drainage (EVD) ranged from 10 to 40 days with concomitant intracranial pressure monitoring at the neurointensive care unit. Approximately 200 cases of this syndrome have been described in the literature. The causes are varied and superimposable to those of high-pressure hydrocephalus. Neurological impairment is due to ventricular size and not to pressure values. Subzero drainage is still the most commonly used method, but other treatments have been described, such as neck wrapping, ventriculostomy of the third ventricle, and lumbar blood patches when associated with lumbar puncture. Its pathophysiology is not clear, although it seems to involve changes in the permeability and viscoelasticity of the brain parenchyma together with an imbalance in CSF circulation in the craniospinal subarachnoid space.

Acute negative-pressure hydrocephalus: Management algorithm and value of early endoscopic ventriculostomy

INTRODUCTION

Acute negative-pressure hydrocephalus is an uncommon, underrecognized patology with a high morbidity and mortality. We propose an algorithm to facilitate the management of these patients, promoting the early diagnosis and the use of endoscopic third ventriculostomy as initial therapeutic option.

METHODS

We performed an observational retrospective study in which patients diagnosed with acute negative-pressure hydrocephalus were included. Patient age and symptoms, primary etiology of hydrocephalus, previous shunt, infection and surgical procedures, time from clinical deterioration to endoscopic procedure, definitive treatment and patient outcomes were recorded. Our management algortihm is exposed and justified.

RESULTS

We identified five patients with diagnosis of acute negative-pressure hydrcephalus. In four of them the management algorithm was applied and early diagnosis and endoscopic ventriculostomy were performed. We observed complete succes of the endoscopic procedure in two patients (50%); the other two required permanent shunt, nevertheless resolution of the low-pressure state was achieved. One patient died after systemic infection (20%), 80% of the patients experienced good outcome.

CONCLUSIONS

The early identification of a negative-pressure hydrocephalic state is essential to reduce complications. Application of a specific management algortihm and early endoscopic third ventriculostomy could be advantageous to achieve better outcomes.

Low-pressure CSF shunt malfunction without preceding lumbar puncture treated by epidural blood patch: report of 2 cases

Low-pressure CSF shunt malfunction is a poorly understood complication of hydrocephalus affecting patients of all ages. Treatment commonly requires external drainage of CSF to subatmospheric pressures for days to weeks in an intensive care setting. The current communication describes the repurposing of an established therapeutic technique, epidural blood patch, for successful initial management in 2 cases of low-pressure shunt malfunction in the absence of a recognized spinal CSF fistula. This technique may shorten length of stay and obviate potential morbidity in the management of what is otherwise a vexatious clinical problem.

Negative-pressure hydrocephalus in the course of a complex postoperative intracranial pressure disturbance: illustrative case

BACKGROUND

Negative-pressure hydrocephalus (NePH) is a rare clinical entity that presents on the background of ventriculomegaly with atypical symptoms. Its diagnosis is difficult, and some patients experience several shunt revisions until the proper solution is found.

OBSERVATIONS

The authors present a patient who developed acute deterioration due to iatrogenic NePH after surgery for a vertebral artery thrombosed giant aneurysm. The deterioration occurred after the insertion of a lumbar drain by which the authors intended to reduce a postoperative subcutaneous cerebrospinal fluid (CSF) collection. The drainage created an unexpected negative-pressure gradient in the CSF spaces, which resulted in NePH. Interventions, such as extraventricular drainage and blood patch, corrected the negative transmantle pressure and stabilized the patient’s condition.

LESSONS

Because the pathophysiology of NePH is theoretically considered to be caused by negative transmantle pressure, the intervention should be performed in order to deal with the coexistence of obstruction in the CSF pathways and a CSF leak. A blood patch would be an effective option in treating the CSF leak when the site of leakage is certain. This is the first case in which a blood patch was effectively applied in the treatment for NePH with a favorable outcome without any permanent CSF diversion.

Acute negative-pressure hydrocephalus: Management algorithm and value of early endoscopic ventriculostomy

INTRODUCTION

Acute negative-pressure hydrocephalus is an uncommon, underrecognized patology with a high morbidity and mortality. We propose an algorithm to facilitate the management of these patients, promoting the early diagnosis and the use of endoscopic third ventriculostomy as initial therapeutic option.

MATERIAL AND METHODS

We performed an observational retrospective study in which patients diagnosed with acute negative-pressure hydrocephalus were included. Patient age and symptoms, primary etiology of hydrocephalus, previous shunt, infection and surgical procedures, time from clinical deterioration to endoscopic procedure, definitive treatment and patient outcomes were recorded. Our management algortihm is exposed and justified.

RESULTS

We identified 5patients with diagnosis of acute negative-pressure hydrcephalus. In 4 of them the management algorithm was applied and early diagnosis and endoscopic ventriculostomy were performed. We observed complete succes of the endoscopic procedure in 2 patients (50%); the other 2required permanent shunt, nevertheless resolution of the low-pressure state was achieved. One patient died after systemic infection (20%), 80% of the patients experienced good outcome.

CONCLUSIONS

The early identification of a negative-pressure hydrocephalic state is essential to reduce complications. Application of a specific management algortihm and early endoscopic third ventriculostomy could be advantageous to achieve better outcomes.

Acute low-pressure hydrocephalus: a case series and systematic review of 195 patients

OBJECTIVE

Acute low-pressure hydrocephalus (ALPH) is characterized by clinical manifestations of an apparent raised intracranial pressure (ICP) and ventriculomegaly despite measured ICP that is below the expected range (i.e., typically ≤ 5 cm H2O). ALPH is often refractory to standard hydrocephalus intervention protocols and the ICP paradox commonly leads to delayed diagnosis. The aim of this study was to characterize ALPH and develop an algorithm to facilitate diagnosis and management for patients with ALPH.

METHODS

EMBASE, MEDLINE, and Google Scholar databases were searched for ALPH cases from its first description in 1994 until 2019. Cases that met inclusion criteria were pooled with cases managed at the authors' institution. Patient characteristics, presenting signs/symptoms, precipitating factors, temporizing interventions, definitive treatment, and patient outcomes were recorded.

RESULTS

There were 195 patients identified, with 42 local and 153 from the literature review (53 pediatric patients and 142 adults). Decreased level of consciousness was the predominant clinical sign. The most common etiologies of hydrocephalus were neoplasm and hemorrhage. While the majority of ALPH occurred spontaneously, 39% of pediatric patients had previously undergone a lumbar puncture. Prior to ALPH diagnosis, 92% of pediatric and 39% of adult patients had a ventricular shunt in situ. The most common temporizing intervention was subatmospheric CSF drainage. The majority of patients underwent a shunt insertion/revision or endoscopic third ventriculostomy as definitive ALPH treatment. Although the mortality rate was 11%, 83% of pediatric and 49% of adult patients returned to their pre-ALPH neurological functional status after definitive treatment. Outcomes were related to both the severity of the underlying neurosurgical disease causing the hydrocephalus and the efficacy of ALPH treatment.

CONCLUSIONS

ALPH is an underrecognized variant phenotype of hydrocephalus that is associated with multiple etiologies and can be challenging to treat as it frequently does not initially respond to standard strategies of CSF shunting. With early recognition, ALPH can be effectively managed. A management algorithm is provided as a guide for this purpose.