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

Abstract

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 carrier a shunt for normotensive hydrocephalus diagnosed ten years before. At the moment of 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.

Keywords: external ventricular drainage; low-pressure hydrocephalus; negative-pressure hydrocephalus; subzero drainage; leptomeningeal glioneural tumor.

Figure 1

(a) NMR at admission showing fourth ventricle lesion and obstructive hydrocepahlus. (b) Postsurgical period with development of low-pressure hydrocephalus, needing several shunts revisions. (c) NMR one month after the placement of shunt asociated a PROSA^® device as “a free tube”.

Figure 2

Images (a,b) show pre- and post-surgery for medulloblastoma with meningeal involvement. Images (c,d) correspond to the state of low-pressure hydrocephalus that was maintained for weeks. Image (e) continuous intraparenchymal ICP monitoring with externalized distal catheter and after its internalization as a “free tube”. This corresponds to CT images (c,d). Image (f) illustrates clinical improvement with marked hyper drainage and tumor response. The patient was carrying a MIETHKE proSA^® antigravitational unit adjusted at zero. Image (f) was taken 12 months later with the antigravitational unit adjusted at 40 mmHg.

Figure 3

Image (a) shows condition prior to the placement of the first shunt system. Images (b,c) correspond to the moment when the patient was diagnosed with a leptomeningeal oncologic process and developed hydrocephalus, despite pressure reductions. Note the subarachnoid space occupied by tumor content. Images (d,e) show response to systemic treatment with visualization of the cisterns. The last CT even shows meningeal enhancement and laminar ventricles suggestive of hyper drainage.

Figure 4

Image (a) shows patient in a coma at the time of the first surgical revision. Image (b) patient with EVD at pressures of −15 cm H₂O with which she remains awake. Image (c) patient with the definitive shunt (Miethke M-Blue^® unit programmed at zero as a free tube) placed by neuronavigation due to the patient’s poor tolerance to ventricular dilatation. Note the transependymal edema that persists despite normalization of ventricular size.

Figure 5

Image (a) pre-surgical and immediate post-surgical images of patient n 5 (b): development of hydrocephalus being treated with EVD. Image (c): normalization of ventricular size at day 25 after subzero drainage. Image (d): new ventricular dilatation despite definitive shunt treated by a new wide external catheter in left ventricle. Image (e): magnetic resonance imaging at discharge. Hyperdrainage signs are seen with ventricular size almost normalized.

Figure 6

Image (a) First image at the patient admission and in the immediate postoperative period (b): development of hydrocephalus after the replacement of cranial vault, without clinical response with low-pressure shunt. Image (c): with EVD at negative pressures, the patient recovers their level of consciousness without tolerating any increase above the EAC. Image (d): shunt programmed at 9 mmHg with distal catheter in right atrium. Normalization of the level of consciousness and basal ventricular size with mild signs of hyper drainage in NMR, which suggests predominance of negative pressure exerted by the atrium.