Classifications of hydrocephalus based on Walter Dandy and his paradigm.

PURPOSE: The purpose of this review is to assess the early work of Walter Dandy leading to a paradigm or model that led to the first classification of hydrocephalus and resulted in the development of treatments. METHODS: The modern understanding of hydrocephalus begins with the works of Walter Dandy. The purpose of this review is to discuss what was changed in the second decade of the 20th century and how the outcome is useful today. As a result of his experiments during that time he was able to recognize the role of the choroid plexus in the production of cerebrospinal fluid (CSF) within the cerebral ventricles. He then identified the role of obstruction blocking the flow of CSF from the ventricles to the absorption of CSF to the systemic vascular. As a result of those findings he showed that there were two forms of hydrocephalus and therefore the first classification of hydrocephalus into obstructive hydrocephalus and communicating hydrocephalus. Very soon after the publication of the experiments there was general agreement of this work by neurosurgeons working on hydrocephalus. The findings published in "experimental hydrocephalus" became a paradigm useful for all or the vast percentage of those neurosurgeons. RESULTS: Dandy was the first to create a classification of hydrocephalus into obstructive and communicating hydrocephalus. He developed treatments for hydrocephalus such as removal of the choroid plexuses that remained in use until effective valved shunts became available in the 1950s. Essentially all subsequent classifications begin with this paradigm. CONCLUSION: Over time there have been new classifications primarily focused on specific uses. It is important that classifications in the sciences be reviewed periodically to include new findings and new ideas. Since the expectation that hydrocephalus can be treated or even cured new classifications tend to focus on the physics of CSF, the choice of treatment and the outcome in specific subgroups. These thoughts should be seen as additions to the paradigm.

How to define CSF overdrainage: a systematic literature review.

PURPOSE: Overdrainage (OD) is one of the most frequent complications related to drainage of the cerebrospinal fluid (CSF). It is mostly associated with valve-bearing shunt systems but should probably be considered as a risk factor in any type of CSF diversion procedure. There is extreme variation in the reported incidence of OD due to the lack of consensus on defining criteria and an unclear perception of the pathophysiology. Hence, OD is probably underreported and underestimated. The objective of this paper was to establish a definition of OD, based on a systematic review of the literature. METHODS: A systematic search was conducted in MEDLNE and EMBASE. Studies providing a definition or a description of diagnostic findings related to OD in ventriculoperitoneal shunt treated hydrocephalus were included. Non-English titles, abstracts and manuscripts were excluded. Extracted descriptions were graded into five groups (class I-V studies) based on how precise the terminology used to describe OD was. Class I studies were included for further analysis and characteristics of OD were extracted. The quality of included descriptions was assessed by a clinical expert panel. RESULTS: A total of 1309 studies were screened, 190 were graded into groups, and 22, which provided specific definitions or descriptions of OD, were graded as class I studies. We extracted 32 different characteristics consistent with OD (e.g., clinical symptoms, radiological signs, and syndromes). CONCLUSION: There was an overall agreement that CSF overdrainage following implantation of a ventriculoperitoneal shunt in a mixed pediatric and adult population is characterized as a persistent condition with clinically manifestations as postural dependent headache, nausea, and vomiting and/or radiological signs of slim ventricles and/or subdural collections.

The ASPECT Hydrocephalus System: a non-hierarchical descriptive system for clinical use.

In patients with hydrocephalus, prognosis and intervention are based on multiple factors. This includes, but is not limited to, time of onset, patient age, treatment history, and obstruction of cerebrospinal fluid flow. Consequently, several distinct hydrocephalus classification systems exist. The International Classification of Diseases (ICD) is universally applied, but in ICD-10 and the upcoming ICD-11, hydrocephalus diagnoses incorporate only a few factors, and the hydrocephalus diagnoses of the ICD systems are based on different clinical measures. As a consequence, multiple diagnoses can be applied to individual cases. Therefore, similar patients may be described with different diagnoses, while clinically different patients may be diagnosed identically. This causes unnecessary dispersion in hydrocephalus diagnostics, rendering the ICD classification of little use for research and clinical decision-making. This paper critically reviews the ICD systems for scientific and functional limitations in the classification of hydrocephalus and presents a new descriptive system. We propose describing hydrocephalus by a system consisting of six clinical key factors of hydrocephalus: A (anatomy); S (symptomatology); P (previous interventions); E (etiology); C (complications); T (time-onset and current age). The "ASPECT Hydrocephalus System" is a systematic, nuanced, and applicable description of patients with hydrocephalus, with a potential to resolve the major issues of previous classifications, thus providing new opportunities for standardized treatment and research.

Intracranial Hypertension with Patent Basal Cisterns: Controlled Lumbar Drainage as a Therapeutic Option. Selected Case Series.

BACKGROUND: There are pathological conditions in which intracranial hypertension and patent basal cisterns in computed tomography coexist. These situations are not well recognized, which could lead to diagnostic errors and improper management. METHODS: We present a retrospective case series of patients with traumatic brain injury, subarachnoid hemorrhage, and cryptococcal meningitis who were treated at our intensive care unit. Criteria for deciding placement of an external lumbar drain were (1) intracranial hypertension refractory to osmotherapy, hyperventilation, neuromuscular blockade, intravenous anesthesia, and, in some cases, decompressive craniectomy and (2) a computed tomography scan that showed open basal cisterns and no mass lesion. RESULTS: Eleven patients were studied. Six of the eleven patients treated with controlled lumbar drainage are discussed as illustrative cases. All patients developed intracranial hypertension refractory to maximum medical treatment, including decompressive craniectomy in Four of the eleven cases. Controlled external lumbar drainage led to immediate and sustained control of elevated intracranial pressure in all patients, with good neurological outcomes. No brain herniation, intracranial bleeding, or meningitis was detected during this procedure. CONCLUSIONS: Our study provides preliminary evidence that in selected patients who develop refractory intracranial hypertension with patent basal cisterns and no focal mass effect on computed tomography, controlled lumbar drainage appears to be a therapeutic option. In our study there were no deaths or complications. Prospective and larger studies are needed to confirm our results.

Long-term telemetric intracerebral pressure monitoring as a tool in intracranial hypotension.

Intracranial hypotension (IH) remains a difficult neurosurgical diagnosis. Relying solely on the symptomatology may be misleading for both diagnosis and assessment of treatment effect as symptoms may resemble other conditions not related to IH. As such, paraclinical supplements in both diagnosis and treatment follow-up are warranted. We present a 42-year-old male with IH treated with computed tomography-guided epidural blood patch. The diagnosis and treatment assessment included continual intracerebral pressure (ICP) monitoring. We found ICP monitoring helpful in IH diagnosis and long-term assessment of treatment and propose this modality as a supplement in difficult IH cases.

Hydrocephalus in infants: the unique biomechanics and why they matter.

OBJECT: Hydrocephalus diagnosed prenatally or in infancy differs substantially from hydrocephalus that develops later in life. The purpose of this review is to explore hydrocephalus that begins before skull closure and full development of the brain. Understanding the unique biomechanics of hydrocephalus beginning very early in life is essential to explain two poorly understood and controversial issues. The first is why is endoscopic third ventriculostomy (ETV) less likely to be successful in premature babies and in infants? The second relates to shunt failure in a subset of older patients treated in infancy leading to life-threatening intracranial pressure without increase in ventricular volume. METHODS: The review will utilize engineering concepts related to ventricular volume regulation to explain the unique nature of hydrocephalus developing in the fetus and infant. Based on these concepts, their application to the treatment of complex issues of hydrocephalus management, and a review of the literature, it is possible to assess treatment strategies specific to the infant or former infant with hydrocephalus-related issues throughout life. RESULTS: Based on engineering, all hydrocephalus, except in choroid plexus tumors or hyperplasia, relates to restriction of the flow of cerebrospinal fluid (CSF). Hydrocephalus develops when there is a pressure difference from the ventricles and a space exterior to the brain. When the intracranial volume is fixed due to a mature skull, that difference is between the ventricle and the cortical subarachnoid space. Due to the distensibility of the skull, hydrocephalus in infants may develop due to failure of the terminal absorption of CSF. The discussion of specific surgical treatments based on biomechanical concepts discussed here has not been specifically validated by prospective trials. The rare nature of the issues discussed and the need to follow the patients for decades make this quite difficult. A prospective registry would be helpful in the validation of surgical recommendations. CONCLUSION: The time of first intervention for treatment of hydrocephalus is an important part of the history. Treatment strategies should be based on the assessment of the roll of trans-mantle pressure differences in deciding treatment strategies. Following skull closure distension of the ventricles at the time of shunt failure requires a pressure differential between the ventricles and the cortical subarachnoid space.

Pathogenesis of hydrocephalus in achondroplastic dwarfs: a review and presentation of a case followed for 22 years.

OBJECT: The purpose of this work is to review the pathogenesis and pathophysiology of hydrocephalus in patients with achondroplasia as a guide to its management throughout life. METHODS: A review of the literature related to neurosurgical issues in achondroplasia with specific focus on cerebrospinal fluid physics, clinical management, and outcome of affected individuals. Issues involved in this review are highlighted by a case report of a patient shunted for achondroplasia first shunted in infancy and followed for 22 years. Each of the management issues is explored with respect to this patient. FINDINGS: Head circumferences in achondroplasia are abnormally large in this condition usually caused by excess cerebrospinal fluid in the cortical subarachnoid space. Increase in ventricular size (hydrocephalus) is not rare but should not be treated unless rapidly progressive or symptomatic. The underlying cause of the abnormalities of cerebrospinal fluid dynamics relates to abnormal venous drainage at the skull base. Patients shunted in infancy for hydrocephalus usually remain dependent on the shunt for life, and crises of high intracranial pressure may occur with no distention of the ventricles. CONCLUSIONS: In infants with achondroplasia, large heads and enlarged ventricles without symptoms should be watched initially for progression. If hydrocephalus progresses or if symptoms of intracranial hypertension occur, endoscopic third ventriculostomy can be tried. If shunt is necessary, it should have a high opening pressure and a device to retard siphoning. In the case of recurrent ventricular catheter blockage, it may be necessary to create a communication between the ventricles and the cortical subarachnoid space.

Successful endoscopic third ventriculostomy in children depends on age and etiology of hydrocephalus: outcome analysis in 51 pediatric patients.

PURPOSE: Endoscopic third ventriculostomy (ETV) has become the method of choice in the treatment of hydrocephalus. Age and etiology could determine success rates (SR) of ETV. The purpose of this study is to assess these factors in pediatric population. METHODS: Retrospective study on 51 children with obstructive hydrocephalus that underwent ETV was performed. The patients were divided into three groups per their age at the time of the treatment: < 6, 6-24, and > 24 months of age. All ETV procedures were performed by the same neurosurgeon. RESULTS: Overall SR of ETV was 80% (40/51) for all etiologies and ages. In patients < 6 months of age SR was 56.2% (9/16), while 6-24 months of age was 88.9% (16/18) and > 24 months was 94.1% (16/17) (p = 0.012). The highest SR was obtained on aqueductal stenosis. SR of posthemorrhagic, postinfectious, and spina bifida related hydrocephalus was 60% (3/5), 50% (1/2), and 14.3% (1/7), respectively. While SR rate at the first ETV attempt was 85.3%, it was 76.9% in patients with V-P shunt performed previously (p = 0.000). CONCLUSIONS: Factors indicating a potential failure of ETV were young age and etiology such as spina bifida, other than isolated aqueductal stenosis. ETV is the method of choice even in patients with former shunting. Fast healing, distensible skulls, and lower pressure gradient in younger children, all can play a role in ETV failure. Based on our experience, ETV could be the first method of choice for hydrocephalus even in children younger than 6 months of age.

Laser interstitial thermal therapy: A first line treatment for seizures due to hypothalamic hamartoma?

Successful treatment of hypothalamic hamartoma (HH) can result in the resolution of its sequelae including epilepsy and rage attacks. Risks and morbidity of open surgical management of this lesion have motivated the development of laser interstitial thermal therapy (LITT) as a less invasive treatment approach to the disease. Although overall morbidity and risk would appear to be lower, complications related to LITT therapy have been reported, and the longer-term follow-up that is now possible after initial experience helps address the question of whether LITT provides equivalent efficacy compared to other treatment options. We conducted a retrospective analysis of clinical outcomes in eight patients undergoing LITT for HH at our center using the Visualase/Medtronic device. Five patients had refractory epilepsy, one had rage attacks, and two had both. We also compared the published seizure-free outcomes over time and the complication rates for different interventional approaches to the treatment of epilepsy due to HH including open craniotomy, neuroendoscopic, radiosurgical, and radiofrequency approaches. With a mean follow-up of 19.1 months in our series of eight patients, six of seven epilepsy patients achieved seizure freedom, whereas the one patient with rage attacks only did not have improvement of his symptoms. A length of hospital stay of 2.6 days reflects low morbidity and rapid postoperative recuperation with LITT. Considering other reported series and case reports, the overall published seizure freedom rate of 21 of 25 patients is superior to published outcomes of HH cases treated by stereotactic radiosurgery (SRS), craniotomy, or neuroendoscopy, and comparable to radiofrequency ablation. The cumulative experience of our center with other published series supports relatively lower operative morbidity than more invasive approaches and efficacy that is as good or better than open craniotomy procedures and SRS. Although morbidity appears to be lower than other open approaches, complications related to LITT and their avoidance should be considered carefully.

Cognition in epilepsy patients with hypothalamic hamartomas.

Many patients with epilepsy caused by hypothalamic hamartomas (HHs) have cognitive impairments during the course of the disease or following neurosurgical treatment. The purpose of this study was to assess cognitive function in these patients, as well as factors influencing preoperative cognitive performance and cognitive outcome after neurosurgical treatment. Using the two largest and most detailed neuropsychology datasets on HH and epilepsy from two centers, we retrospectively report on cognitive functions in 48 patients with structural epilepsy due to HH (mean age ± standard deviation [SD] 20 ± 12 years, range 5-53 years, median 16 years; disease duration mean 17 ± 11 years). Intelligence, verbal learning and recall, and speed and executive functions (processing speed and cognitive flexibility) were assessed before and on average 19 (±11) months after surgery (interstitial radiosurgery: N = 22; neurosurgical resection/disconnection: N = 26). Prior to neurosurgical treatment, 52% of patients showed impaired executive and 62% showed reduced verbal memory functions. A trend for a detrimental effect of higher drug load on cognitive functioning was found. After neurosurgical treatment, intellectual functions for the entire cohort tended to increase. This correlated with improved seizure frequency and decreased number of antiepileptic drugs (AEDs). However, postoperative outcomes for individual patients were highly variable, with significant deteriorations in 17% (processing speed) to 34% (cognitive flexibility and verbal learning), and performance increases in 17% (intellectual functioning) up to 39% (processing speed) of the patients. Higher levels of presurgical performance were significant predictors of cognitive decline after surgery. These results are highly relevant for patient consultation and may help with therapeutic decisions.

Hydrocephalus associated with childhood nonaccidental head trauma.

OBJECTIVE The incidence of posttraumatic ventriculomegaly (PTV) and shunt-dependent hydrocephalus after nonaccidental head trauma (NAHT) is unknown. In the present study, the authors assessed the timing of PTV development, the relationship between PTV and decompressive craniectomy (DC), and whether PTV necessitated placement of a permanent shunt. Also, NAHT/PTV cases were categorized into a temporal profile of delay in admission and evaluated for association with outcomes at discharge. METHODS The authors retrospectively reviewed the cases of patients diagnosed with NAHT throughout a 10-year period. Cases in which sequential CT scans had been obtained (n = 28) were evaluated for Evans' index to determine the earliest time ventricular dilation was observed. Discharge outcomes were assessed using the King's Outcome Scale for Childhood Head Injury score. RESULTS Thirty-nine percent (11 of 28) of the patients developed PTV. A low admission Glasgow Coma Scale (GCS) score predicted early PTV presentation (within < 3 days) versus a high GCS score (> 1 week). A majority of PTV/NAHT patients presented with a subdural hematoma (both convexity and interhemispheric) and ischemic stroke, but subarachnoid hemorrhage was significantly associated with PTV/NAHT (p = 0.011). Of 6 patients undergoing a DC for intractable intracranial pressure, 4 (67%) developed PTV (p = 0.0366). These patients tended to present with lower GCS scores and develop ventriculomegaly early. Only 2 patients developed hydrocephalus requiring shunt placement. CONCLUSIONS PTV presents early after NAHT, particularly after a DC has been performed. However, the authors found that only a few PTV/NAHT patients developed shunt-dependent hydrocephalus.

Aquaporins in Brain Edema and Neuropathological Conditions.

The aquaporin (AQP) family of water channels are a group of small, membrane-spanning proteins that are vital for the rapid transport of water across the plasma membrane. These proteins are widely expressed, from tissues such as the renal epithelium and erythrocytes to the various cells of the central nervous system. This review will elucidate the basic structure and distribution of aquaporins and discuss the role of aquaporins in various neuropathologies. AQP1 and AQP4, the two primary aquaporin molecules of the central nervous system, regulate brain water and CSF movement and contribute to cytotoxic and vasogenic edema, where they control the size of the intracellular and extracellular fluid volumes, respectively. AQP4 expression is vital to the cellular migration and angiogenesis at the heart of tumor growth; AQP4 is central to dysfunctions in glutamate metabolism, synaptogenesis, and memory consolidation; and AQP1 and AQP4 adaptations have been seen in obstructive and non-obstructive hydrocephalus and may be therapeutic targets.

Long term outcome after surgical treatment for hypothalamic hamartoma.

PURPOSE: To determine long-term outcome for seizure control and clinical predictors for seizure freedom in patients undergoing surgical treatment for epilepsy associated with hypothalamic hamartoma (HH). METHODS: 155 patients underwent surgical treatment for HHs and treatment-resistant epilepsy at one center (Barrow Neurological Institute at St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA) between February 2003 and June 2010. Data collection included medical record review and direct follow-up interviews to determine seizure outcome. Statistical analysis included descriptive summaries of patient characteristics and time-to-event analysis for seizure freedom. RESULTS: Long-term survival with follow-up of at least five years since first surgical treatment was available for 108 patients (69.7% of the treatment cohort). The surgical approach for first HH intervention consisted of transventricular endoscopic resection (n = 57; 52.8%), transcallosal interforniceal resection (n = 35; 32.4%), pterional resection (n = 7; 6.5%), and gamma knife radiosurgery (n = 9; 8.3%). Multiple surgical procedures were required for 39 patients (36.1%). There were 10 known deaths from all causes in the treatment cohort (6.5%). Of these, one (0.6%) was related to immediate complications of HH surgery, three (1.9%) were attributed to Sudden Unexpected Death in Epileptic Persons (SUDEP), and one (0.6%) to complications of status epilepticus. For surviving patients with long-term follow-up, 55 (50.9%) were seizure-free for all seizure types. Univariable analysis showed that seizure-freedom was related to 1) absence of a pre-operative history for central precocious puberty (p = 0.01), and 2) higher percentage of HH lesion disconnection after surgery (p = 0.047). Kaplan-Meier survival analysis shows that long-term seizure outcome following HH surgery is comparable to short-term results. SUMMARY: These uncontrolled observational results show that long-term seizure control following HH surgical treatment is comparable to other forms of epilepsy surgery. Late relapse (at least one year after surgery) and SUDEP do occur, but in a relatively small number of treated patients. These results inform clinical practice and serve as a comparable benchmark for newer technologies for HH surgery, such as magnetic resonance imaging-guided laser interstitial thermal therapy, where long-term outcome results are not yet available.

Fifth International Hydrocephalus Workshop, Crete, Greece, May 20-23, 2010: themes and highlights.

The purpose of the Fifth International Hydrocephalus Workshop was to allow clinicians and basic science researchers to educate each other in the advances that have been and are being made in the understanding and treatment of hydrocephalus and related disorders. This vision of the meeting was the work of Dr. Anthony Marmarou, who died a few months before the meeting was held. The presentations on all aspects of the study of hydrocephalus can be roughly grouped into seven basic themes. These themes are a summary of the important lifelong work of Professor Marmarou himself, including mathematical modeling, clinical selection of patients for the treatment of normal pressure hydrocephalus, and the development of international guidelines for the management of this condition. Other themes included the gathering of data, and in particular, randomized controlled trials; the use of magnetic resonance imaging for basic research in hydrocephalus, basic science and in particular the role of aquaporins; reports on clinical studies; and the late outcomes for patients treated in infancy. Finally, a report on the development of a consensus on the definition and classification of hydrocephalus based on the point of obstruction to flow of cerebrospinal fluid was presented.

Microsurgical Management of Complex Hypothalamic Hamartomas in the Era of Minimally Invasive Therapy: A Case Series and Narrative Review.

BACKGROUND: There has been a paradigm shift in the management of hypothalamic hamartoma (HH) from traditional microsurgical techniques to less invasive alternatives. However, large and extensive HH may fail to respond to these therapies, necessitating craniotomies. METHODS: All patients who underwent microsurgical resection of a complex HH by the 2 senior authors from 2011 to 2021 were included. Charts were retrospectively reviewed and demographic, clinical, imaging, and outcome data were recorded. RESULTS: Eight patients (mean age, 7 years) were included. Two had failed previous treatments. All 7 presented with gelastic seizures and cognitive dysfunction, 6 showed central precocious puberty, and 3 had behavioral problems. The mean lesion size was 21.6 mm and all had interpeduncular extension, 5 had intraventricular extension (Delalande type I, 3; type III, 4; type IV, 1). A frontotemporal orbitozygomatic approach with optic nerve decompression was used in all patients, supplemented by another approach in 3 (endoscopic transventricular, 3; transcallosal, 1). Gross total resection was achieved in 6 patients and subtotal resection in 2. Transient complications occurred in 3 patients (37.5%): self-limited sodium imbalance (n = 3), subdural hygroma (n = 2). Permanent complications occurred in 2 patients (25%): perforator infarct (n = 1) and short-term memory loss (n = 1). All patients experienced seizure resolution with preserved hypothalamic-pituitary axis function. After a mean follow-up of 41 months (range, 2-66 months), 7 patients remained seizure free, and 1 had rare seizures. Cognitive and behavioral symptoms improved in all patients. CONCLUSIONS: For large HH with interpeduncular extension, microsurgery via the frontotemporal orbitozygomatic approach is a safe and highly effective treatment modality.

Successful third surgery for a case of status gelasticus: lessons learned after nearly 200 cases of hypothalamic hamartoma surgical resection.

We report the case of a 3-year-old boy with status gelasticus symptomatic to a giant hypothalamic hamartoma despite two previous hypothalamic hamartoma surgeries using pterional approaches from each side. Following his third resection employing an endoscopic, transventricular approach, he has been seizure free for 6 months with significant cognitive, behavioral, and electroencephalographic improvement. This case reinforces the importance of surgery for a form of status epilepticus and in addition that repeat (three) surgeries can be successful, indeed life changing. The optimal surgical approaches and management plan for hypothalamic hamartoma surgery-including subtemporal, subfrontal, transcallosal, and endoscopic approaches-are discussed, including how these treatment decisions have evolved as a result of our large series experience.

EEG and video-EEG seizure monitoring has limited utility in patients with hypothalamic hamartoma and epilepsy.

PURPOSE: Hypothalamic hamartomas (HHs) are a malformation of the ventral hypothalamus and tuber cinereum, associated with gelastic seizures and epilepsy. We sought to determine the spectrum of electroencephalography (EEG) abnormalities in a large cohort of HH patients. METHODS: Data was collected for HH patients undergoing evaluation between 2003 and 2007. Data included seizure history, prior treatment, and results of diagnostic studies. After informed consent, data were entered into a database. KEY FINDINGS: We reviewed 133 HH patients. Mean age at time of data analysis was 15.7 years (59.4% male). Most patients had gelastic (77%) and/or complex partial seizures (58%). Records for 102 EEG studies on 73 patients were reviewed. Interictal epileptiform abnormalities were seen in 77%, localizing predominately to the temporal and frontal regions. Records for 104 video-EEG (VEEG) studies on 65 patients were reviewed. Of 584 gelastic seizures (GS) captured, no ictal EEG change was noted in 438 (75%). Of GS with localizing features, 89% suggested onset from the temporal and/or frontal regions. There were 160 complex partial seizures (CPS). For those with localizing features, 100% localized to the temporal and/or frontal head regions. EEG and VEEG findings correlated with the side of HH attachment. VEEG did not influence outcome. SIGNIFICANCE: EEG features in HH patients are diverse. The majority of gelastic seizures fail to demonstrate change in the EEG. The lack of EEG changes with many clinical seizures, and the false localization seen in those events with an ictal change suggest the utility of EEG is limited in the evaluation of these patients.