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

J Neurosurg 135:300–308, 2021

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.

Ultra-low-pressure hydrocephalic state in NPH: benefits of therapeutic siphoning with adjustable antigravity valves

Acta Neurochirurgica (2020) 162:2967–2974

Idiopathic normal-pressure hydrocephalus (NPH) is a condition of the elderly treated by ventriculoperitoneal shunt (VP) insertion. A subset of NPH patients respond only temporarily to shunt insertion despite low valve opening pressure. This study aims to describe our experience of patients who benefit from further CSF drainage by adding adjustable antigravity valves and draining CSF at ultra-low pressure.

Methods Single-centre retrospective case series of patients undergoing shunt valve revision from an adjustable differential pressure valve with fixed antigravity unit to a system incorporating an adjustable gravitational valve (Miethke proSA). Patients were screened from a database of NPH patients undergoing CSF diversion over 10 consecutive years (April 2008– April 2018). Clinical records were retrospectively reviewed for interventions and clinical outcomes.

Results Nineteen (10F:9M) patients underwent elective VP shunt revision to a system incorporating an adjustable gravitational valve. Mean age 77.1 ± 7.1 years (mean ± SD). Eleven patients (58%) showed significant improvement in walking speed following shunt revision. Fourteen patients/carers (74%) reported subjective improvements in symptoms following shunt revision.

Conclusions Patients presenting symptoms relapse following VP shunting may represent a group of patients with ultra-low pressure hydrocephalus, for whom further CSF drainage may lead to an improvement in symptoms. These cases may benefit from shunt revision with an adjustable gravitational valve, adjustment of which can lead to controlled siphoning of CSF and drain CSF despite ultra-low CSF pressure.

Low-pressure Hydrocephalus in Children

Neurosurgery 80:439–447, 2017

Low-pressure hydrocephalus (LPH) is a rare phenomenon characterized by a clinical picture consistent with elevated intracranial pressure (ICP) and ventricular enlargement, but also a well-functioning shunt and low or negative ICP.

OBJECTIVE: To report our experience in evaluating this challenging problem. METHODS: Patients with LPH were identified from several sources, including institutional procedural databases and personal case logs. Electronic medical records were reviewed to collect demographic, clinical, surgical, and radiographic data to determine the presence of LPH. Each patient’s clinical course, including presentation, management, and outcome, is reported.

RESULTS: Thirty instances of LPH were identified in 29 patients. Eleven cases (37.9%) of LPH were after lumbar puncture (LP), and 19 cases (62.1%) occurred without any preceding spinal procedure. Among the post-LP patients, conservative measures alone were successful in 3 cases (27%); lumbar blood patch was successful in 2 cases (18%); and 6 cases (55%) required external cerebrospinal fluid (CSF) drainage. Of the spontaneous cases, 5 patients did not receive the full spectrum of treatment because of terminal prognosis. Of the remaining 14 patients, 11 (78.6%) required external CSF drainage. Post-LP patients required fewer days of external CSF drainage (median, 4 [range, 0-12] vs median, 11 [range, 0-90]) and had a shorter hospital stay (median, 2 [range, 2-16] vs median, 8 [range, 0-26]).

CONCLUSION: This study represents the largest series of LPH. Although its pathophysi-ology remains a mystery, there are a variety of management options. Multiple procedures and a protracted hospital stay are often required to successfully treat LPH.

 

Low-pressure hydrocephalus: indication for custom-made catheters?

Low-pressure hydrocephalus- indication for custom-made catheters?

Acta Neurochir (2013) 155:1981–1985

Low-pressure hydrocephalus (LPH) is characterized by ventriculomegaly with persistent low intracranial pressure (ICP). Sub-zero drainage is needed for its management and multiple solutions have been described. Our aim is to report our experience with custom-made peritoneal catheters with larger inner diameter as an alternative treatment option.

Methods We made a retrospective review of all patients diagnosed with LPH and treated with custom-made peritoneal catheters at the Virgen del Rocío Pediatric Neurosurgical Unit. Catheters were coated with antibiotic or silver. The inner diameter of ventricular catheters was 1.4 mm; peritoneal catheters were larger than usual (1.9 mm inner diameter).

Results We identified four patients in whom five custommade peritoneal catheters were used over a 3-year period. There were two males and the mean age was 10 years (6 months–17 years). In all patients, placement of an EVD was necessary for sub-zero drainage, with maximum negative pressure of −8 cm H20. The mean time of maintenance of EVD was 102 days (10 days–1 year). Finally, three ventriculoperitoneal (VP) valveless systems, one with antigravitation device, and one Pro-GAV VP shunt were placed, all of them with larger custom-made peritoneal catheters. After a mean follow-up period of 2.3 years (6 months– 3 years), two patients are completely recovered, one patient is partially dependent for daily activities with good cognitive status, and the last one is a child who died due to his brain tumor.

Conclusion The custom-made peritoneal catheters with larger inner diameter could be a good option for the management of this complex pathology.

Revision to an adjustable non-siphon control valve in low pressure hydrocephalus

Low pressure Hydrocephalus

Clinical Neurology and Neurosurgery 115 (2013) 175– 178

High intracranial compliance states requiring negative pressure drainage, otherwise known as low-pressure hydrocephalus syndromes, are rare conditions. The use of siphoning, enabled by revision to an adjustable shunt without an anti-siphon device, has been largely unexplored in low-pressure hydrocephalus.

Methods: Three patients with presumed normal pressure hydrocephalus (NPH) presented with unresolved symptoms, including urinary incontinence, disturbed gait, and cognitive dysfunction. Each was inadequately treated despite confirmed functioning Strata II valves (with built-in siphon control device) calibrated to the lowest pressure setting for maximum drainage. Surgical revision to Strata non-siphon control (NSC) valves was performed to allow for additional drainage via siphoning.

Results: Following revision to a shunt with a “siphoning” device, each patient achieved improved neurological function. Each differential pressure valve was initially set to a higher setting than with the Strata II valve. One of our patients experienced the formation of a subdural hematoma after shunt revision; resolution following adjustment of the valve to a higher setting suggests that siphoning may be of less importance to overdrainage syndromes when compared with valve opening pressure.

Conclusion: Our findings indicate that intermittent intracranial hypotension achieved by siphoning is effective in the treatment of a subset of patients presenting clinically with NPH. Direct conversion to a shunt system without an anti-siphon device allows reduction of ventricular size without the risk associated with external ventricular drainage (EVD). With conversion to the Strata NSC valve, our patients had sustained clinical improvement, even at higher valve settings.