Negative-pressure Hydrocephalus Research Articles

Low-/Negative-Pressure Hydrocephalus: To Understand the Formation Mechanism from the Perspective of Clinicians.

Low-/negative-pressure hydrocephalus (LPH/NePH) is uncommon in clinical practice, and doctors are unfamiliar with it. LPH/NePH is frequently caused by other central nervous system diseases, and patients are frequently misdiagnosed with other types of hydrocephalus, resulting in delayed treatment. LPH/NePH therapy evolved to therapeutic measures based on "external ventricular drainage below atmospheric pressure" as the number of patients with LPH/NePH described in the literature has increased. However, the mechanism of LPH/NePH formation is unknown. Thus, understanding the process of LPH/NePH development is the most important step in improving diagnosis and treatment capability. Based on case reports of LPH/NePH, we reviewed theories of transcortical pressure difference, excessive cerebral venous drainage, brain viscoelastic changes, and porous elastic sponges.

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.

Clinical characteristics of and treatment strategy for hydrocephalus in patients with severe disorders of consciousness.

Making an appropriate diagnosis and effective treatment for hydrocephalus in patients with severe disorders of consciousness (DOC) remains controversial and difficult. Given that the typical symptoms are usually concealed by the limited behavioral responsiveness of patients with severe DOC, hydrocephalus diagnosis is likely to be missed in the clinic. Even if not, the presence of hydrocephalus may reduce the likelihood of DOC recovery, posing a conundrum for clinicians. From December 2013 to January 2023, the clinical data and therapeutic schedule of hydrocephalus in patients with severe DOC at Huashan Hospital's Neurosurgical Emergency Center were studied retrospectively. Sixty-eight patients [mean age (± SD) 52.53 ± 17.03 years, 35 males and 33 females] with severe DOC had been included. The hydrocephalus was discovered after computerized tomography (CT) or magnetic resonance imaging (MRI) revealed enlarged ventricles in the patients. During the hospitalization, the patient underwent a surgical treatment that included a ventriculoperitoneal (V-P) shunt and/or cranioplasty (CP) implantation. Following the surgery, an individualized V-P pressure was established based on the patient's ventricle size and neurological function variation. To account for the improvement in consciousness in patients with severe DOC, the Glasgow Coma Scale (GCS) and the Coma Recovery Scale-Revised (CRS-R) assessments were performed before and after hydrocephalus treatment. All severe DOC patients have varying degrees of ventricular enlargement, deformation, and poor brain compliance. Approximately 60.3% (41/68) of them had low- or negative-pressure hydrocephalus (LPH or NegPH). 45.5% (31/68) of the patients had a one-stage V-P shunt and CP operation performed concurrently, while the remaining 37 patients had a single V-P shunt operation performed independently. Beside of two DOC patients developed surgical complications, 92.4% (61/66) of the survivors showed an improvement in consciousness after hydrocephalus treatment. In patients with severe DOC, LPH or NegPH was common. Secondary hydrocephalus in DOC patients had been largely ignored, hampering their neurological rehabilitation. Even months or years after the onset of severe DOC, active treatment of hydrocephalus can significantly improve patients' consciousness and neurological function. Meanwhile, this study summarized several evidence-based treatment experiences of hydrocephalus in patients with DOC.

Negative-Pressure Hydrocephalus Treated with a Modified Shunt System: A Case Report

Negative-Pressure Hydrocephalus Treated with a Modified Shunt System: A Case Report

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

IntroductionAcute 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. MethodsWe 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. ResultsWe 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. ConclusionsThe 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.

Diagnosis and Management for Secondary Low- or Negative-Pressure Hydrocephalus and a New Hydrocephalus Classification Based on Ventricular Pressure

Low-pressure hydrocephalus (LPH) and negative-pressure hydrocephalus (NegPH), secondary to traumatic brain injury, cerebral hemorrhage, tumor resection, and central nervous system (CNS) infection in adults, are seldom reported. They have not been recognized enough pathophysiologically in previous clinical practice. They used to have poor prognosis, and routine shunt surgery has unsatisfactory outcomes. The current classifications of hydrocephalus do not provide proper guidance for clinical practice, especially for LPH and NegPH. Thirty-nine cases of LPH and NegPH were included from January 2013 to March 2018. Clinical features and image characteristics were reviewed. The prognosis of these patients were evaluated by Glasgow Outcome Scale-Extended (GOS-E) within 3 months after external ventricular drainage or ventriculoperitoneal (VP) shunt accepted. Management strategies were discussed in detail. Ventricular pressure was lower than 70 mm H2O in all 39 patients, and the lowest value was-10 cm H2O. About an average of 3.5 operations were completed for every patient. Eighteen cases had CNS infection. Eight patients died. Besides 2 patients lost to follow-up, all patients had a poor prognosis with an average GOS-E score of 2.7. For the 29 surviving patients, the time interval from onset to last VP shunt achieved was 31-3880 days, with an average of 376 days. Both LPH and NegPH used to have poor prognosis. However, a good prognosis can be achieved by proper management with a further understanding of the pathophysiology. A new classification for hydrocephalus was proposed according to ventricular pressure, which is necessary and reasonable.

Hemangioblastomatosis-associated negative-pressure hydrocephalus managed with improvised shunt

Low-pressure hydrocephalus (LPH) is a rare clinical diagnosis, characterized by neurologic decline and ventriculomegaly that persists despite normal to low intracranial pressure. LPH is typically managed by negative-pressure drainage via ventriculostomy, followed by low-resistance shunt insertion. We present the case of a middle-aged man with a history of hemangioblastomatosis who had spontaneous subarachnoid hemorrhage. He was treated with a ventriculoperitoneal shunt and then underwent resection of a Meckel’s cave hemangioblastoma and whole brain irradiation. One month later, he presented to us with worsening symptoms and hydrocephalus despite shunt interrogations and revisions revealing no malfunction. Ventriculostomy drainage at negative-pressure was required for resolution of symptoms and ventriculomegaly, leading us to a diagnosis of LPH. This was successfully treated using an improvised ultra-low pressure valveless ventriculoperitoneal shunt, with maintained resolution of LPH for over one year. The system was created by ligating the distal slit valve end of a peritoneal catheter to prevent reflux and allow sub-zero pressure drainage by siphoning.

Successful treatment of negative pressure hydrocephalus using timely titrated external ventricular drainage: a case series

ObjectiveNegative-pressure hydrocephalus (NegPH) is a rare clinical entity characterised by enlarged ventricles and symptoms consistent with increased intracranial pressure (ICP) in the setting of negative ICP. Little has been published regarding appropriate treatment and outcomes of negative-pressure hydrocephalus patients, and no data have been published demonstrating successful therapy producing acceptable long-term outcomes. Here we present 8 cases successfully treated by titrated external ventricular drainage (TEVD), including drainage at negative (subatmospheric) pressure, and subsequent low-pressure ventriculoperitoneal shunting. MethodsA retrospective audit of all cases of negative-pressure hydrocephalus occurring at a university teaching hospital between 2006 and 2012 was undertaken. The clinical features of these cases, results of radiological investigations, treatment, and outcome were drawn from the patients’ records. ResultsEight cases of NegPH were identified. All patients had at least one preceding intracranial procedure (mean number of procedures 3.0). All cases were treated using TEVD, titrated to produce between 5 and 15mL per hour of CSF drainage, including drainage under subatmospheric pressure if this was required to maintain CSF flow. Mean delay from first negative ICP to TEVD was 1.8 days. All 8 patients demonstrated clinical improvement. TEVD resulted in improvement in Glasgow Coma Scale (mean increase 4.6, p=0.003), and increases in ICP (mean increase 8.5, p<0.001). Mean length of follow-up was 471.8 days. At follow-up, four patients had returned to pre-morbid functioning, three had a reduction in functioning attributable to their initial presentation (not NegPH), and one had died of unknown cause. Illustrative case descriptions are included. ConclusionsNegative-pressure hydrocephalus is a rare but underrecognised syndrome that can be successfully treated by timely external ventricular drainage titrated to maintain CSF flow, and subsequent low-pressure ventriculoperitoneal shunting.

Treatment of refractory low-pressure hydrocephalus with an active pumping negative-pressure shunt system

Low-pressure hydrocephalus is a rare type of hydrocephalus characterized by negative intracranial pressure (ICP) and ventriculomegaly. Given the shortcomings of available methods to treat refractory low-pressure hydrocephalus, we set out to develop a new system for evacuation of cerebrospinal fluid (CSF) from the ventricular system where existing shunt systems do not produce the necessary gradient for CSF drainage. We retrospectively reviewed the charts of two patients with the diagnosis of negative-pressure hydrocephalus refractory to traditional treatments. We combined a traditional low-pressure, non-siphoning valve with a pumping chamber placed distal to the valve to create a system that could be actively pumped to remove excess CSF. Treatment of negative-pressure hydrocephalus requires the establishment of a lower ventricular drainage pressure than the drainage pressure in the subarachnoid space. In refractory cases, we propose the use of this active negative-pressure pumping system.

Negative-pressure and low-pressure hydrocephalus: the role of cerebrospinal fluid leaks resulting from surgical approaches to the cranial base

Negative-pressure and low-pressure hydrocephalus are rare clinical entities that are frequently misdiagnosed. They are characterized by recurrent episodes of shunt failure because the intracranial pressure is lower than the opening pressure of the valve. In this report the authors discuss iatrogenic CSF leaks as a cause of low- or negative-pressure hydrocephalus after approaches to the cranial base. The authors retrospectively reviewed cases of low-pressure or negative-pressure hydrocephalus presenting after cranial approaches complicated with a CSF leak at their institution. Three patients were identified. Symptoms of high intracranial pressure and ventriculomegaly were present, although the measured pressures were low or negative. A blocked communication between the ventricles and the subarachnoid space was documented in 2 of the cases and presumed in the third. Shunt revisions failed repeatedly. In all cases, temporary clinical and radiographic improvement resulted from external ventricular drainage at subatmospheric pressures. The CSF leaks were sealed and CSF communication was reestablished operatively. In 1 case, neck wrapping was used with temporary success. Negative-pressure or low-pressure hydrocephalus associated with CSF leaks, especially after cranial base approaches, is difficult to treat. The solution often requires the utilization of subatmospheric external ventricular drains to establish a lower ventricular drainage pressure than the drainage pressure created in the subarachnoid space, where the pressure is artificially lowered by the CSF leak. Treatment involves correction of the CSF leak, neck wrapping to increase brain turgor and allow the pressure in the ventricles to rise to the level of the opening pressure of the valve, and reestablishing the CSF route.

The importance of the cortical subarachnoid space in understanding hydrocephalus

In this paper the authors define the role of the cortical subarachnoid space (CSAS) in poorly understood forms of hydrocephalus to cerebrospinal fluid (CSF) dynamics to improve understanding of the importance of the CSAS and its role in selecting patients for endoscopic third ventriculostomy (ETV). The secondary purpose of this work was to define testable hypotheses to explain enigmatic disorders of CSF dynamics and to suggest how these concepts could be tested. The magnitude of the contribution of the CSAS is explored using the solid geometry of concentric spheres. With this starting point, clinical conditions in which CSF dynamics are not easily understood are explored regarding the potential role of the CSAS. Overall, problems of CSF dynamics are easily understood. Insights may be gained when the results of a pathological process or its treatment vary from what has been expected. Acute changes in ventricular volume at the time that hydrocephalus develops, the failure of shunts, and the changes in ventricular volume with shunt repair may occur very rapidly. Changes in the volume of water in the brain, especially in the brain substance itself, are unlikely to occur at this rapid rate and may be interpreted as a simple redistribution of the CSF between the ventricle and CSAS with no initial change in the actual volume of brain parenchyma. Problems such as pseudotumor cerebri, shunt failure with nonresponsive ventricles, and negative-pressure hydrocephalus can be explained by assessing the ability of ventricular CSF to flow to the CSAS and the ability of this fluid to exit this compartment. Ventricular enlargement at the time of shunt failure implies a failure of flow between the ventricles and CSAS, implying that all patients who show this phenomenon are potential candidates for ETV. The important role of the CSAS in the pathophysiology of various forms of hydrocephalus has been largely ignored. Attention to the dynamics of the CSF in this compartment will improve understanding of enigmatic conditions of hydrocephalus and improve selection criteria for treatment paradigms such as ETV. These concepts lead to clearly defined problems that may be solved by the creation of a central database to address these issues.