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.

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.

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.

Surgical resection of hypothalamic hamartomas for severe behavioral symptoms.

Hypothalamic hamartomas (HHs) are associated with treatment-resistant epilepsy. Many patients also experience severe and sometimes disabling psychiatric problems. The most common behavioral symptoms consist of paroxysms of uncontrolled anger related to poor frustration tolerance. These can include violence, resulting in disrupted family or school relationships, and legal consequences including incarceration. In a large cohort of patients undergoing surgical resection of HHs for refractory epilepsy, 88% of families described an improvement in overall behavioral functioning [1]. Here, we describe four patients (three males, mean age=11.9 years) who underwent surgical resection of HHs largely for behavioral indications. Three patients had relatively well controlled seizures, and one had no history of epilepsy. All patients had striking improvement in their psychiatric comorbidity. HH resection can result in significant improvement in behavioral functioning, even in patients with relatively infrequent seizures. Further investigation under approved human research protocols is warranted.

A consensus on the classification of hydrocephalus: its utility in the assessment of abnormalities of cerebrospinal fluid dynamics.

BACKGROUND: Between 2009 and 2011 an attempt has been made to develop a consensus on the classification of hydrocephalus. Clinicians and basic scientists who are recognized internationally for their work in hydrocephalus attended working meetings in which the concepts of classification of hydrocephalus were discussed at length. PURPOSE: This review attempts to explain the relevance of a classification scheme based on the point of obstruction to the flow of cerebrospinal fluid to basic science research into the pathophysiology and effects of hydrocephalus. The review is designed to give examples of the value of this classification in analyzing research utilizing animal models. The development of hydrocephalus in the absence of a point of obstruction (true communicating hydrocephalus) is analyzed. CONCLUSION: Contemporary neuroimaging techniques are now available that can identify the actual point of obstruction to the flow of CSF, if any, which results in the development of hydrocephalus. Such identification may lead to improved ability to analyze animal models used in hydrocephalus research as well as deciding among various treatment options.

Hydrocephalus and aquaporins: lessons learned from the bench.

PURPOSE: Hydrocephalus is a common disorder of defective cerebrospinal fluid (CSF) turnover. The identification of the aquaporin water channels (AQPs) led to the study of their role in the composition of biological fluids including CSF. The purpose of this study is to review the potential role of aquaporins in the pathogenesis, compensation, and possibly treatment of hydrocephalus. METHODS: We performed a MEDLINE search using the terms "aquaporin AND hydrocephalus." The search returned a total of 20 titles. Eleven studies fulfilled the criteria for this review. RESULTS: Most studies were performed in animal models. The expression of AQPs in hydrocephalus is significantly altered. Aquaporin-1 levels at the choroid plexus are decreased in most models of hydrocephalus while CSF production and intracranial pressure are reduced in AQP1 knockout mice. In contrast, the expression of AQP4 in hydrocephalus is increased at its sites of expression. Aquaporin-4 knockout mice show a decreased clearance of brain edema via blood-CSF and blood-brain barrier (BBB) pathways and decreased survival in hydrocephalus models. CONCLUSIONS: Aquaporin-1 is highly expressed at the choroid plexus and is related to CSF production. Aquaporin-4 is expressed at the ependyma, glia limitans, and at the perivascular end feet processes of astrocytes of the BBB, facilitating the water movement across these tissue interfaces. The observations obtained from animal studies and few cases in humans indicate an adaptive and protective role of AQPs in hydrocephalus by decreasing CSF production and increasing edema clearance. Aquaporins are attractive targets for the pharmaceutical treatment of hydrocephalus.

Pediatric multilevel spine injuries: an institutional experience.

OBJECT: Spinal column trauma is relatively uncommon in the pediatric population, representing 1-2% of all pediatric fractures. However, pediatric spinal injury at more than one level is not uncommon. The purpose of this study was to evaluate the mechanisms and patterns of the injury and factors affecting management and outcomes of pediatric multilevel spine injuries. PATIENTS AND METHODS: Patients with pediatric spine injury (183) were retrospectively reviewed. Patients (28 boys, 20 girls; mean age 12.8 years; range 3 to 16 years) identified with multilevel spinal injuries were 48 (26.2%): 7 patients (14.5%) were between 3 and 9 years of age, and 41 patients (85.5%) were between 9 and 16 years of age. Of the 48 patients, 30 (62.5%) were at contiguous levels and 18 (37.5%) were at noncontiguous. A total of 126 injured vertebrae were diagnosed. The cervical region alone was most frequently (31.2%) involved, and the thoracic region alone was the least frequently involved (12.5%). Overall, 73% of patients were neurologically intact, 4.1% had incomplete spinal cord injury (SCI), and 8.3% had complete SCI. Treatment was conservative in 36 (75%) patients. Surgical treatments were done in 12 patients (25%). Postoperatively, one patient (16.6%) with initial neurologic deficit improved. The overall mortality rate was 6.2%. CONCLUSIONS: Multilevel spine injuries are most common in children between 9 and 16 years of age and are mainly located in the cervical region. The rostral injury was most often responsible for the neurologic deficit. The treatment of multilevel spine injuries should follow the same principles as single level injury, stability and neurologic symptoms indicate the appropriate treatment.

Orbitozygomatic resection for hypothalamic hamartoma and epilepsy: patient selection and outcome.

PURPOSE: This study aims to examine the outcomes of ten patients after orbitozygomatic (OZ) pterional surgery in cases of refractory epilepsy caused by hypothalamic hamartomas (HH). METHODS: Ten patients with HH and treatment-resistant epilepsy (mean age 18.3 years, range 0.7 to 42.7) underwent HH resection with an OZ approach (n = 8) or an OZ approach combined with a transventricular endoscopic approach (n = 2). Follow-up for the patients ranged from 0.5 to 6.2 years (mean 3.1). Outcomes were prospectively monitored with the use of a proprietary database. RESULTS: Four patients (40%) are seizure-free, and four (40%) have had greater than 50% reduction in seizures. One patient had no significant change in seizure frequency, and one patient died unexpectedly 2.8 years after surgery. Six patients had total or near-total HH resection (98-100% of HH lesion volume). Of these, four of six (66%) were seizure-free, and two had at least greater than 50% reduction in seizures. Residual complications include diabetes insipidus (n = 1), poikilothermia (n = 1), visual field deficit (n = 1), and hemiparesis (n = 1). Eight families (80%) reported improved quality of life. CONCLUSIONS: Patients with treatment-resistant epilepsy and tumors with an inferior or horizontal plane of attachment to the hypothalamus should continue to be approached from below. Those with both intrahypothalamic and parahypothalamic components may require approaches from above and below, either simultaneously or staged. For appropriately selected patients, the success of controlling seizures with an OZ is comparable to results utilizing transcallosal or transventricular approaches. The likelihood of controlling seizures appears to correlate with extent of resection.