The management of hydrocephalus in the pediatric patient

Treatment of Hydrocephalus in Adults Mark G. Hamilton, MD The following patients with multiple complex diagnoses define the adult hydrocephalus popula...
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Treatment of Hydrocephalus in Adults Mark G. Hamilton, MD The following patients with multiple complex diagnoses define the adult hydrocephalus population: (1) transition patients (previously treated for hydrocephalus as children), (2) adults with previously untreated congenital hydrocephalus, (3) adults with acquired hydrocephalus with an identifiable etiology, and (4) patients with suspected or proven idiopathic normal pressure hydrocephalus. Restricting the outpatient care or hydrocephalus clinic definition to a single hydrocephalus patient subpopulation limits our understanding of these patients and effectively abandons the remaining adult patients with hydrocephalus to a less focused and potentially less effective healthcare arrangement. A comprehensive adult hydrocephalus clinic model is described and recommended to advance our understanding of this diverse patient population, which will ultimately lead to the development and provision of a better standard of patient care. Semin Pediatr Neurol 16:34 – 41 © 2009 Elsevier Inc. All rights reserved.

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he management of hydrocephalus in the pediatric patient is well described and far-reaching. There is a long history of comprehensive care models that include the spectrum from the outpatient clinic setting through emergency evaluation and surgical management. Pediatric neurosurgeons have established a paradigm of care that acknowledges hydrocephalus as a chronic disease that requires an all-inclusive and frequently multidisciplinary strategy.1-13 As a positive consequence, the long-term outcome for pediatric patients with hydrocephalus has improved significantly over the last 3 decades. Is the access to surgical management of adult hydrocephalus adequate for all patients? If all neurosurgeons are treating adult hydrocephalus patients, are all neurosurgeons able to provide the surgical options of ventriculoperitoneal (VP) shunting, ventriculoatrial shunting, and endoscopic third ventriculostomy (ETV) for patients with the appropriate indications? To provide appropriate care for adult patients with hydrocephalus requires that all of the surgical options appropriate to their clinical condition be available. A neurosurgeon should be well versed in the therapeutic indications and proficient in the performance of these procedures. However, if one assumes that capable neurosurgeons can effectively perform the specific surgical treatment of identified patients, it

From the Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada; Division of Pediatric Neurosurgery, Alberta Children’s Hospital, Calgary, Alberta, Canada; and Division of Neurosurgery, Foothills Hospital, Calgary, Alberta, Canada. Address reprint requests to Mark G. Hamilton, MDCM, FRCS, Division of Neurosurgery, Foothills Hospital, 12th Floor 1403, 29th Street NW, Calgary, Alberta, T2N 2T9, Canada. E-mail: [email protected]

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1071-9091/09/$-see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.spen.2009.02.001

still leaves unknown the quality of the decision-making process for the management of these patients. In other words, are the appropriate patients receiving what is regarded as the most appropriate treatment? In addition, management is not simply defined as “surgical” but must also include the possibility for “observation.” Compared with what happens for pediatric patients, a different model of care has existed for the adult patient with hydrocephalus that is typically not multidisciplinary and rarely occurs in a focused environment. Much is written about the surgical care of the adult patient with hydrocephalus and about the investigation and treatment for adult patients with idiopathic normal pressure hydrocephalus (iNPH). There currently exist hydrocephalus clinics almost solely dedicated to the assessment and management of patients with potential iNPH.14-16 The adult hydrocephalus population, however, is more complex and heterogeneous than just this one patient subtype. Within the adult hydrocephalus patient population are former pediatric patients with multiple potential causes, adults with previously undiagnosed congenital hydrocephalus (so-called “arrested” hydrocephalus); patients who develop hydrocephalus because of trauma, infection, hemorrhage, or tumor; and those patients with suspected iNPH.17,18 With the exception of the iNPH population, the management of these patients has typically been piecemeal and noncomprehensive. What management strategies exist or should exist for the different adult hydrocephalus patient populations? The ability to follow the entire population of patients with adult hydrocephalus creates the opportunity to develop a better understanding of the natural history of both treated and untreated patients, establish and test observational and treat-

Treatment of hydrocephalus in adults ment protocols, and facilitate clinical research. There are many unanswered questions, unasked questions, and much that can be learned about the natural history and management decision making in the adult hydrocephalus population. To accomplish this will require the creation of a uniform vocabulary and classification scheme for diagnosis. As well, future evaluations should be broadened as much as possible to include all hydrocephalus patients and in particular to avoid using “surgical experience” as the denominator for the adult hydrocephalus patient population. Untreated patients in the observational arm must also be included when discussing management strategies. Limited information is currently available regarding the actual demographics of the adult hydrocephalus population. As an example, Tisell et al19 reported the indications for surgery for hydrocephalus in the adult population in Sweden between 1996 and 1999, determining that NPH accounted for 47% or most of the surgeries. The high percentage of surgeries for NPH that Tisell reported does not accurately reflect what is thought to be the true incidence of iNPH in the adult hydrocephalus population, most likely because their definition of NPH was different and included other hydrocephalus etiologies. In addition, as discussed, this type of report by its structure ignores patients with a diagnosis of hydrocephalus who are not surgically treated. How important are these questions about adult hydrocephalus? The quality of life (QOL) and economic impact associated with both the failure to treat and treatment of adult hydrocephalus is significant.20-24 These patients deserve the advocacy, focused care, and consideration that a comprehensive adult hydrocephalus clinic model can provide.

35 hydrocephalus; other congenital malformation—associated hydrocephalus; and intraventricular hemorrhage associated with prematurity, infections, trauma, and brain tumors.1,18 Many have complex hydrocephalus-management issues managed over their “pediatric” life by pediatric neurosurgeons and may have experienced multiple VP shunt revisions (Fig 1). Some are described as having “nonfunctioning shunts” and therefore “arrested hydrocephalus.” Similar to what will be discussed in the untreated adult hydrocephalus or APUCH subpopulation, the following management dilemmas apply as well to this patient group: (1) how can one

Adult Hydrocephalus Outpatient Classification Hydrocephalus in the adult patient has numerous classifications. How does one categorize “adult hydrocephalus” as it pertains to assessment and follow-up in an outpatient clinic setting? From the viewpoint of clinical management, I propose the following organizational scheme: (1) transition patients (patients previously diagnosed with hydrocephalus or treated for it as children), (2) adults identified with previously untreated congenital hydrocephalus (adult with previously untreated congenital hydrocephalus (APUCH)); (3) adults with acquired hydrocephalus with an identifiable etiology, and (4) patients with suspected or proven iNPH.

Transition Patients As the survival of pediatric patients with hydrocephalus continues to improve, these patients will become adults in need of hydrocephalus care at an ever-increasing rate. Most of these patients have undergone treatment for their hydrocephalus. However, a small but growing number will have been identified as having “arrested” hydrocephalus that has never been treated and will need long-term monitoring.25 This patient population has multiple etiologies responsible for their hydrocephalus including myelomeningocele-related

Figure 1 (A) An axial brain computed tomography scan of a 35-yearold patient with a diagnosis of myelomeningocele. The patient is clinically stable. (B) An axial brain computed tomography scan of a 20-year-old patient with a diagnosis of hydrocephalus associated with intraventricular hemorrhage of prematurity. The patient is clinically stable.

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M.G. Hamilton Transition from child to adult care for patients with hydrocephalus does not occur in a consistent or comprehensive fashion for most patients and is often described as traumatic for many patients and families.26 The small amount of literature that is available deals predominately with the myelomeningocele patient population. Vinchon and Dhellemmes27 presented a series of 450 adult patients with hydrocephalus that also included patients with myelomeningocele. They provided data that confirmed the need to follow these patients long-term; shunt malfunction can occur more than 20 years after insertion, and death from shunt obstruction occurred in 1% of their transition patient population. Furthermore, Rickert et al28 described sudden death in 4 adult patients with “chronic” hydrocephalus, and McDonnell and McCann29 reported deaths occurring in adult patients with myelomeningocele. These patients are typically managed at a treatment center either by an ad hoc general neurosurgeon or by the “designated” neurosurgeon. Less commonly, a pediatric neurosurgeon who is able and allowed to continue managing the hydrocephalus problems of their former pediatric patients will provide care. Vinchon and Dhellemmes27 refers to this latter care model as subspecialization “by disease instead of by age.”

Adult with Previously Untreated Congenital Hydrocephalus (APUCH)

Figure 2 (A) Sagittal T1-weighted brain magnetic resonance imaging scan and (B) an axial T2-weighted magnetic resonance imaging scan showing hydrocephalus with a patent aqueduct. The patient is 45 years old and symptomatic with gait and cognitive problems and was treated with a VP shunt. The patient experienced symptom improvement.

determine if treatment or future treatment (new or “revision”) is necessary (ie, what parameters to follow and what threshold for intervention); and (2) if treatment or “revision” is undertaken, what is the most appropriate method of treatment (ie, shunt or ETV)?

The APUCH is typically referred to as having “arrested or compensated hydrocephalus.”25 Arrested hydrocephalus is a broad term that has also been used to describe treated patients who have “compensated” despite suspected or confirmed surgical treatment failure. Other terms include longstanding overt ventriculomegaly in adults,30,31 late-onset idiopathic aqueductal stenosis,17 or the syndrome of hydrocephalus in young and middle-aged adults. Of note, not all of these patients have aqueductal stenosis (Fig. 2) or what is typically referred to as “obstructive hydrocephalus.” The following management dilemmas that were presented for the pediatric patient with “arrested hydrocephalus” also apply to this patient group: (1) how can one determine if treatment is necessary (ie, what parameters should be followed, and what is an appropriate threshold for intervention); and (2) if treatment is undertaken, what is the most appropriate method of treatment (ie, shunt or ETV)? Too often we have heard the stories about patients with “arrested” or “compensated” hydrocephalus who present in a delayed fashion after suffering significant neurologic deterioration related to their hydrocephalus, having been told initially that they did not have a problem that required clinical follow-up. Although much has been written in recent years as more of these patients are identified,17,25,30-33 these basic questions currently remain unanswered. The potential to address these questions exists within the comprehensive adult hydrocephalus clinic model.

Adults with Acquired Hydrocephalus With an Identifiable Etiology Patients in this grouping are the most integrated of the four adult hydrocephalus subgroups into general adult neurosur-

Treatment of hydrocephalus in adults

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gical practice. These patients typically develop hydrocephalus because of subarachnoid hemorrhage (Fig. 3), tumor (Fig. 4), trauma (Fig. 5), colloid cyst (Fig. 6), or infection. Traditionally, a general neurosurgeon or relevant-subspecialty neurosurgeon has undertaken the hydrocephalus management for these patients. The primary disease rather than the hydrocephalus diagnosis typically directs the management and follow-up strategy for these patients. There is some limited information about the natural history and long-term prognosis of the hydrocephalus management for these different patient subgroups.23,34-37

Figure 4 A sagittal T1-weighted brain magnetic resonance imaging scan with gadolinium of a 65-year-old patient showing a pineal region tumor producing symptomatic hydrocephalus. The tumor was endoscopically biopsied and the hydrocephalus successfully managed with an ETV.

Patients with Suspected or Proven iNPH This patient population has captured the attention of the neurosurgical community and is synonymous for many with “adult hydrocephalus.” Patients with this diagnosis have one of the only truly potentially treatable causes of dementia (Fig. 7). Marmarou et al have reported that 5% of the population in a

Figure 3 (A) An axial brain computed tomography scan of a 42-yearold patient with subarachnoid hemorrhage showing aneurysm clips and (B) an axial computed tomography scan showing a VP shunt used to manage symptomatic hydrocephalus.

Figure 5 An axial brain computed tomography scan of a 21-year-old patient with severe neurologic injury secondary to trauma with hydrocephalus treated using a VP shunt.

M.G. Hamilton

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patient population but to reiterate that it represents only one type of adult hydrocephalus that can also be effectively managed in a comprehensive adult hydrocephalus clinic.

Multidisciplinary Clinics The multidisciplinary myelomeningocele clinic model initially established the foundation for structure of pediatric hydrocephalus outpatient care.47 The concept was simple, but revolutionary: bring neurosurgeons, urologists, and or-

Figure 6 (A) A sagittal T1-weighted brain magnetic resonance imaging scan showing a colloid cyst of the 3rd ventricle producing obstructive hydrocephalus in a 60-year-old patient with gait and memory difficulties, and (B) a postoperative sagittal T1-weighted magnetic resonance imaging scan showing complete removal of the colloid cyst performed with an endoscope.

nursing home environment met the criteria for iNPH but were not receiving treatment.20 The diagnostic criteria are somewhat problematic, but significant research is being undertaken to improve and validate new and old diagnostic criteria.14-17,38-42 The mainstay of treatment has been VP shunting.17,40,43,44 However, more recently, evidence has suggested a potential role for ETV in the treatment of patients with iNPH.45,46 The purpose of this report was not to discuss the difficulties with diagnosis and treatment of this important

Figure 7 (A) An axial brain computed tomography scan of a 72-yearold patient with suspected iNPH, and (B) an axial brain computed tomography scan after the insertion of a VP shunt showing a reduction in ventricular size. Postoperatively, the patient experienced a dramatic improvement in symptoms.

Treatment of hydrocephalus in adults thopedic surgeons with supportive health care providers together in an outpatient setting to evaluate and recommend treatment in a collaborative fashion. Certain patient subpopulations, such as those with myelomeningocele, may benefit from the multidisciplinary clinic model because certain disease features other than those directly associated with hydrocephalus are common.21,29,48-50 Uncertainty exists as to whether the multidisciplinary clinic model is essential for all adult hydrocephalus patients. However, at a minimum, access to a neuropsychologist, urologist, geriatrician, physiatrist, and other components of rehabilitative medicine may be required during the assessment and care of many adult hydrocephalus patients. Each adult hydrocephalus clinic should at a minimum establish an appropriate network of interested subspecialty physicians and supportive services to assist in patient evaluation and management when needed.

The Skill Set for Surgical Treatment of Adult Hydrocephalus Patients It is important to reiterate the previous comments about being able to offer the entire complement of surgical options to the adult patient with hydrocephalus. This includes the insertion of VP and ventriculoatrial shunts and ETV,17,30-32,38,45,51-55 with an awareness of the potential complications associated with these treatment modalities and strategies to effectively reduce treatment risks. Much of the current “evidence”17,56-58 regarding surgical treatment of hydrocephalus in the adult patient are extrapolated from the randomized controlled trials that have been performed in pediatric patients,4,5,8-11,59-62 but sadly not in adult patients. ETV is now an essential and important component in the management of not only pediatric patients with hydrocephalus but also adult patients with hydrocephalus. Two examples of important changes in the treatment options for hydrocephalus patients are: 1) the use of ETV to facilitate removal of shunts from patients presenting with symptomatic shunt malfunction,51,63-65 2) endoscopic treatment for patients with hydrocephalus associated with a colloid cyst.37 ETV is now a valid option that should be available for select patients in that it offers them the potential for treatment of their hydrocephalus and freedom from shunt revisions. It is essential to be familiar with the ETV as a treatment procedure and to follow all patients long-term. It should never be forgotten that “hydrocephalus is a chronic disease.” Similarly, all patients un-

39 dergoing endoscopic removal of a colloid cyst should be followed long-term.37

The Current State of “the Adult Hydrocephalus Clinic” The population of adult patients with hydrocephalus is increasing as diagnostic and therapeutic techniques enhance identification and survival of treated patients. However, it has been an impression that most hydrocephalus patients are usually assessed and cared for by individual physicians in an unstructured and unfocused clinic environment. To evaluate this assumption, a structured literature search was undertaken for the topic “adult hydrocephalus clinics.” Keywords included hydrocephalus, adult, outpatient clinics, ambulatory care facilities, and clinics. Literature dealing with patients being evaluated in outpatient clinics for possible iNPH and the establishment of transition clinics for pediatric patients with myelomeningocele and hydrocephalus were identified.15,27,48,50,66 No peer-reviewed literature was identified that dealt with a comprehensive adult hydrocephalus clinic model. A Google search performed for [“adult hydrocephalus” clinic] identified a small number of adult hydrocephalus clinics or adult hydrocephalus programs. Most of these programs can also be identified on the Hydrocephalus Association Web site (http://www.hydroassoc.org/education_support/links). However, there is no clear information available regarding the true demographics of the adult hydrocephalus population that can be discerned from these Web sites.

University of Calgary Adult Hydrocephalus Clinic In 2001, Pediatric Neurosurgeons established the University of Calgary Adult Hydrocephalus Clinic with the goal to standardize and enhance the care for adult patients with hydrocephalus. As previously noted, this conforms to what Vichon and Dhellemmes described as subspecialization “by disease instead of by age.”27 In January 2008, there were approximately 800 patients followed or tracked by the University of Calgary Adult Hydrocephalus Clinic. Approximately 300 patients are actively engaged in the clinic (Table 1), and 500 other patients have been identified as having undergone treatment for hydrocephalus between 1994 and 2008. In contrast, 360 children were treated for hydrocephalus at the Alberta Children’s Hospital during the same interval (1994-2008).

Table 1 University of Calgary Adult Hydrocephalus Program Patient Demographics

Hydrocephalus Patient Subpopulation Transition patients Adults with previously untreated congenital hydrocephalus Adults with acquired hydrocephalus iNPH (suspected or proven)

Other Adult Population with Adult Clinic 300 Patients Hydrocephalus Management (2001-2008) 500 Patients (1994-2007) 35% 18% 39% 8%

12% 9% 60% 19%

M.G. Hamilton

40 Table 2 University of Calgary Adult Hydrocephalus Clinic Patient Management (2001-2008) Type of Treatment Performed Shunt ETV Observation

Adult Clinic (300 Patients) 51% 38% 11%

There are inherent differences between the patient population of the clinic and that of the patients treated by neurosurgeons that are not part of the Adult Hydrocephalus Program. Since the initiation of the Adult Hydrocephalus Clinic in 2001, it has become the “home” for most of the transition patients, and most of the patients with previously untreated congenital hydrocephalus (APUCH). Most surgery for patients with acquired hydrocephalus is still done by the subspecialty-specific neurosurgeons. The proportion of patients with iNPH is increasing as the investigation and care for most of these patients has migrated to the Adult Hydrocephalus Clinic. Treatment modalities have included shunting and ETV (Table 2). Endoscopic treatment occurred in 38% of clinic patients. This reiterates the importance of being able to offer more than just shunt insertion or revision as a surgical treatment strategy. Approximately 11% of the active hydrocephalus clinic patients have had no treatment for their hydrocephalus and are being monitored with a combination of clinical, magnetic resonance imaging, and neuropsychological evaluations. Notably, a small percentage of these patients have undergone surgical treatment because of changes in monitored parameters or development of new clinical symptoms or signs. The model does not require that all patients attend the clinic on a yearly cycle. Patients are typically assessed on a schedule that parallels the perceived difficulties associated with their hydrocephalus management. There is no evidence to support yearly assessments or even assessments every 5 years. However, we have defined every 5 years as the maximum time interval between clinic assessments. More importantly, the establishment of the University of Calgary Adult Hydrocephalus Clinic has created a “home” for these patients. They can obtain telephone or outpatient clinic access to address concerns about their hydrocephalus management on a timely basis. Investigative and management protocols have been established and are reevaluated on a routine basis. We have established a network that includes access to neuropsychology, geriatric medicine, neurology, and physical medicine and rehabilitation subspecialties. The vast majority of patient complaints related to their hydrocephalus are investigated on an outpatient basis, thereby avoiding emergency room use and potentially limiting unnecessary diagnostic imaging investigations.

Recommendations and Conclusions It is a mistake to limit the Adult Hydrocephalus Clinic model to a specific part of the adult hydrocephalus patient popula-

tion, such as those with iNPH. The Adult hydrocephalus population is best described as a complicated, diverse, heterogeneous group of patients who should be managed in a structured, focused, comprehensive clinic. The University of Calgary Adult Hydrocephalus Clinic focuses on the care for all adult patients with hydrocephalus in a specialty clinic run by pediatric neurosurgeons. Pediatric neurosurgeons can take the lead in managing the transition care of pediatric patients with hydrocephalus and can apply their expertise to management of the adult patient with both previously treated and untreated hydrocephalus. Equally successful would be a comprehensive clinic run either by adult-oriented neurosurgeons or a combined clinic with both pediatric and adult neurosurgeons. Both neurosurgeon and patient will benefit from the expanded view of adult hydrocephalus care that this expanded clinic model allows.

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