Cómo citar este artículo: Sandoval-Balanzario MA, Rincón-Navarro RA, Granados-López R, Santos-Franco JA. Endoscopic third ventriculostomy for chronic communicating hydrocephalus in adults. Rev Med Inst Mex Seguro Soc. 2015 May-Jun;53(3):280-5.
Received: March 11th 2014
Accepted: September 23rd 2014
Miguel Antonio Sandoval-Balanzario,a Raúl Abraham Rincón-Navarro,b Rommel Granados-López,b Jorge Arturo Santos-Francob
aJefatura del Servicio de Neurocirugía
bServicio de Neurocirugía
Centro Médico Nacional La Raza, Instituto Mexicano del Seguro Social, Distrito Federal, México
Communication with: Miguel Antonio Sandoval-Balanzario
Telephone: (55) 5782 1088, extension 23204
Background: Shunt devices to treat hydrocephalus are associated with a malfunction of 81 % at 12 years and 10 % of infection. The objective was to assess safeness and efficacy of endoscopic third ventriculostomy (ETV) for the treatment of chronic communicating hydrocephalus.
Methods: Eight patients with chronic communicating hydrocephalus were included in a period between September, 2012 and April, 2013. X ray computed tomography scans were performed when patients were admitted, after the surgery, and at 30, 180 and 365 days. The follow-up was of 251 days (the biggest was of 459 days). The variables included were: age, sex, etiology, time of evolution, and the total number of shunt malfunctions. Conventional technique with a 30° rigid endoscope was performed, malfunctional shunt was removed, and a tied shunt device was placed.
Results: Four males and four females, with a mean age of 42 years (27-63 years); neurocysticercosis was identified in five patients (62.5 %); the evolution rate was of 18 years (15-30 years); the hospital stay rate was of 6.5 days (3-22 days); the mean of previous shunt malfunctions was 4 (1-6). Complications: neuroinfection in one patient, malfunction in three patients. None of them died.
Conclusion: ETV is a safety procedure for treating chronic communicating hydrocephalus; it has a success rate higher than 60 %. Neurocysticercosis showed better results when previous shunt malfunctions were lower than three.
Keywords: Communicating hydrocephalus; Neuroendoscopy; Ventriculostomy; Ventriculoperitoneal shunt
Active distension of the cerebral ventricular system by disorder either in production, circulation, or absorption is defined as hydrocephalus. It is a common neurosurgical disease, as primary etiology it is idiopathic normal pressure hydrocephalus, or secondary to processes such as intracranial hemorrhage, tumors, intraventricular infection, cerebral trauma, craniectomy, etc.1 In 1914, Dandy classified it as communicating and non-communicating hydrocephalus.2 The first is most common in adults, and has traditionally been handled by placing a valve system, predominantly either facing the atrium, or into the peritoneal cavity.3 These procedures have a risk of malfunctioning of 25 to 40% in the first year, with an increase of 4 to 5% annually and revision necessary after 12 years in 81% of patients.4 Another cause of morbidity and mortality is the colonization of the systems, with an overall incidence of neuroinfection of 8 to 10%, which, besides the inherent cognitive deficit, raises hospital costs because the patient requires admission to the operating room for removal of the colonized system, intravenous antibiotic therapy for a variable period of time, and placement of a new valve system. Worldwide, the average stay time for this complication is reported at 7 to 21 days and, despite all necessary measures being taken, it is a common recurrent infection.5 Another treatment option is endoscopic third ventriculostomy (ETV); however, the role of this procedure to manage communicating hydrocephalus remains thus far understudied and little understood.3
The first successful EVT was done in 1923, by the urologist William Mixter, who introduced a ureteroscope to penetrate the floor of the third ventricle.6 High success rates have been reported in patients with obstructive etiology, as in aqueduct stenosis. Lower success rates have been reported for patients with communicating hydrocephalus, such as post-infectious, post-hemorrhagic, myelomeningocele, adult idiopathic normal pressure hydrocephalus, and for patients with valvular dysfunction. The overall rate of complications is 8.5% with a 0.6% risk of severe bleeding, 1.8% of neuroinfection, and 1.61% of cerebrospinal fluid (CSF) fistula.7 It is known as secondary EVT when performed after the dysfunction a previously-placed valve system.4
The aim of this study is to evaluate the safety and efficacy of performing an EVT for the management of chronic communicating hydrocephalus in adult patients with valvular dysfunction in short-term follow-up.
Prospective longitudinal study. We included a total of eight adult patients admitted to the Servicio de Neurocirugía del Centro Médico Nacional La Raza, during the period September 2012 to April 2013, with clinical symptoms of intracranial hypertension secondary to communicating hydrocephalus because of prior valve system dysfunction, confirmed by CT on admission, independent of base etiology. Patients with tomographic evidence of obstructive etiology were not included. Cranial tomographic study was performed on admission, immediately post-surgery, at 30 days, and at 6 and 12 months, or outside these periods if necessary. The longest follow-up was 459 days (15 months), and the shortest was 298 days (9 months) in cases of functional EVT. In cases of failed EVT, the follow-up period ended when the CSF was derived by another method. The variables considered were: age, sex, base etiology and its development time, and number of previous valve systems. EVT was considered successful when it presented mainly clinical improvement, including the absence of CT evidence of hydrocephalus. EVT was considered failed when the patient presented a clinical picture of intracranial hypertension in which hydrocephalus is corroborated by tomographic study based on measurements of the Evans index and third ventricle index.8 We included one patient with a history of germinoma of the pineal gland with resection 18 years previous, and radiotherapy as adjuvant treatment. In the tomographic study on their admission there was no evidence of tumor recurrence or any other situation considered obstructive.
Description of the technique
With prior authorization of the surgery and informed consent by the patient, family member, or responsible guardian, the surgical event was done under general anesthesia, in supine position with head neutral. A horseshoe incision of 3 cm was cut and a burr hole of 15 mm was made at Kocher’s point contralateral to the dysfunctional valve system. A rigid endoscope was introduced with a 30° Wolf-brand lens, and irrigation was maintained with a lukewarm Hartmann solution controlled by the surgeon. The stoma on the floor of the third ventricle was done with a conventional technique and blunt instruments to avoid complications.9,10 Under endoscopic vision, the dysfunctional catheter was removed to reduce the risk of intraoperative bleeding from possible adhesions to the choroid plexus. A new ventriculoperitoneal shunt valve system was placed using the trephine of the endoscopy, allowing proper positioning to advance toward the ipsilateral foramen of Monro to subsequently perform ligation of the distal catheter at supraclavicular level in the same surgical event. A linked valve system was placed to decrease the possibility of subjecting the patient to a new surgical event if the EVT ended up failing. In cases where it was necessary to disconnect the derivative system, this was done under local anesthesia with sterile technique in an area assigned for outpatient procedures.
Eight patients were included with the following characteristics: four men and four women, average age 42 years (27-63 years), three (37.5%) were under 40 years. In five patients (62.5%) the underlying disease was neurocysticercosis (NCC); other etiologies were post-infectious (bacterial meningoencephalitis), congenital, and undetermined. As for the number of previous valve systems, the average was 4 (1-6) and average disease development from the first valve system placement was 18 years (15-30 years). The average hospital stay was 6.5 days (3-22 days) (Table I).
|Table I Characteristics of patients included in study|
|Functional EVT||Hospital Stay
|Prior valvular systems|
|F = female; M = male; EVT = Endoscopic third ventriculostomy|
Morbidity and mortality
No patient had intraventricular hemorrhage during or after surgery. No mortality was presented (Table II). One patient had neuroinfection by S. aureus and required readmission to remove the linked valve system because of likely colonization and intravenous management with antibiotic therapy for 21 days; however, EVT remains functional (Figure 1). CSF fistula in surgical wound was presented in a patient with primary etiology of NCC of 30 years of development, so he returned six days after the operation and in tomographic study the presence of hydrocephalus was confirmed; because of this the valve system was disconnected with no problems. The patient had a history of three previous failed valve systems. One patient presented motor aphasia the ninth day after the operation, with CT evidence of hydrocephalus, so we disconnected the valve system. It is worth noting that they were readmitted three months later with valvular dysfunction and underwent replacement of the valve system. This patient has a history of NCC of 18 years development, with three previous valve placements (Figure 2).
|Table II Postoperative complications in some patients|
|Complication||Number of patients|
|Fistula in surgical site*||1|
|*The fistula was presented in one of the patients with failed TVE|
Figure 1 Patient with pathology of post-infectious hydrocephalus. A) Pre-operative CT scan. It shows a dilated ventricular system and dysfunctional intraventricular catheters. B) Control CT at 12 months after the third ETV
Figure 2 Etiology of neurocysticercosis. A) Pre-operative computerized axial tomography (CAT) showing dilated ventricular system and dysfunctional intraventricular catheter. B) Immediately post-operative CAT. C) CAT taken nine days after the operation, again showing dilated ventricular system
EVT and neurocysticercosis
Five patients were noted with base etiology NCC, all with a duration of the disease more than 15 years, and with endoscopic evidence of active disease; some degree of ependymal healing, vasculitis, arachnoiditis in the base cisterns and vesicular lesions attached to ependyma were observed. A better success rate of ETV was found in patients that had a history of two or less failed valve systems (Table III).
|Table III EVT and neurocysticercosis|
|Development (years)||Failed valve systems||Functional EVT|
|EVT = Endoscopic Third Ventriculostomy|
68.9% of EVT failures occurred in the first 180 days post-surgery11 and 82.4% of those failed EVT occurred in the first two weeks.12 Our success rate for secondary EVT was 62.5% in follow-up greater than 298 days because the failed EVT occurred in the first two postoperative weeks. These results, greater than 60%, compared with those obtained in several series; however, no author included neurocysticercosis, which was the primary etiology in the case of our patients with failed EVT.
Kadrian et al. reported in 2005 a success rate of 89% at one month for EVT as primary treatment of non-communicating hydrocephalus; in their study, factors contributing to the failure of the surgery were intraoperative bleeding, thickened floor of the third ventricle, and anatomical abnormalities not displayed in magnetic resonance imaging (MRI), such as interthalamic adhesion.13 The only one found in our patients was the thickened floor of the third ventricle in one patient with a history of bacterial meningoencephalitis at three years of age; however, the EVT remains functional. One can feel sure that despite a failed EVT, the risk of morbidity, mortality or infection to the patient is not increased when a new valvular system is placed.11
Primary EVT versus secondary EVT
Regarding the management of communicating hydrocephalus, in 2005 O'Brien reported a comparative success rate of 27% with primary EVT and 71% with secondary EVT for post-hemorrhagic hydrocephalus, while for post-meningococcal hydrocephalus a success rate was reported from 0 to 75% in primary and secondary EVT, respectively.4 It is suggested that the failure of primary EVT in cases of communicating hydrocephalus is due to blockage of the CSF flow in the subarachnoid space and its absorption into the arachnoid granulations in the superior sagittal sinus mainly by detritus.4 The most important parameter that regulates the flow of CSF through the arachnoid granulations is hydraulic conductivity, which is maintained as a one way valve, and that in the acute process can be affected by clogging with detritus, blood, or an inflammatory process that conditions meningeal fibrosis.14 In addition to absorption in the arachnoid villi in the sagittal sinus, it is documented that the CSF also is absorbed at a rate of 0.11 to 0.23 ml/min into the granulations along the nerve roots in the spinal cord, and that this is higher in physically active subjects.15 Other theories of absorption sites have emerged, such as those who suggest as locations of these sites the optic nerves, olfactory nerves, cribriform plate, and extracranial lymphatic system. This last one is being studied with models in vitro.16 The effectiveness of secondary EVT in post-infectious and post-hemorrhagic hydrocephalus is because, when diverting the CSF flow with a valve system, this allows subarachnoid spaces to re-expand, plus inducing an aqueductal stenosis acquired by continuous CSF diversion; both phenomena are necessary for an EVT to be successful in cases of valvular dysfunction at a later stage of the disease.4
30% of patients with NCC develop hydrocephalus, mainly via chronic arachnoiditis (25.7%), intraventricular cysts (0.7%) and meningeal fibrosis (3.8%). 18% of patients with chronic arachnoiditis have a spontaneous resolution within nine years of diagnosis.17 47% of patients with NCC presented dysfunction via obstruction of the valve system in the first month, thus requiring several valve changes during the course of their illness. Importantly, all patients with a diagnosis of NCC received medical treatment after surgery based on albendazole and corticosteroids in accordance with current consensus guidelines for the treatment of neurocysticercosis, which indicate that with medical treatment there is a decrease in the risk of valve dysfunction, since in this group of patients the incidence of dysfunction is nearly 80%, with a mortality associated with multiple changes higher than 50% at two years, especially if the patient is in active stage.18 An additional feature of neuroendoscopy is the possibility of extracting intracisternal or intraventricular cysts of the parasite, to improve the permeability and flow of CSF into the ventricular and subarachnoid systems, as the degeneration of these cysts causes cytokine release and subsequent activation of the inflammatory cascade throughout the ventricular ependymal surface. The ependyma fixes to the parasite in the ventricular wall, secondarily causing processes of fibrosis and scarring, with decreasing CSF flow.19
EVT and valve replacements
Regarding the number of previous dysfunctional valve systems, a relationship is seen with failed EVT particularly in cases of NCC, which had a number of replacements of three or more. Recent evidence suggests that both free functional CSF access to the arachnoid villi, and rapid transmission of CSF pulsatile pressure through the stoma, lead to the effectiveness of EVT. Shunt valve systems alter the flow and absorption of CSF, which then modifies its intraventricular dynamics considerably, especially in cases in that have required multiple replacements.12
EVT and idiopathic normal pressure hydrocephalus
A special section is idiopathic normal pressure hydrocephalus (INPH), which has traditionally been treated with the placement of a programmable valve system; however, it has not been possible to eradicate the concomitant high risk of developing subdural hematoma or hygroma. Recent studies have reported the application of EVT as an initial operation in these patients, with improvement of symptoms in 72% of patients overall, similar to the improvement obtained by valve systems, but with incidence of hematoma lower than 5%.20
We can establish that EVT is a safe and effective procedure to solve chronic communicating hydrocephalus in adult patients with valvular dysfunction, since we obtained similar results to those reported globally. The shunt valve and EVT offer similar success rates; however, the latter adds the advantage of eliminating the dependence on a valve system and risks of system colonization, exposure, obstruction, and dysfunction that this entails. The data obtained suggest that EVT provides better results for the management of chronic communicating hydrocephalus from NCC presenting with valvular dysfunction in patients whose valve replacements do not exceed two, which is a factor that, at least in our study, does not influence the other etiologies. In following protocols we will assess whether to leave aside the linked valve system, since it increases the risk of neuroinfection by colonization. This study gives us the necessary blueprint to continue carrying out prospective protocols medium and long term, with a larger sample, allowing us to establish the basis for a treatment algorithm for handling communicating hydrocephalus, mainly caused by neurocysticercosis, which it is endemic in our environment.
In this regard, and according to our results, we suggest that the initial treatment of the NCC should be based on etiological medical treatment, anti-inflammatory medical treatment, and in cases of hydrocephalus, EVT as primary treatment or before the first sign of valvular dysfunction. On this basis we may believe that the NCC can be cured permanently. This therapeutic option should be evaluated with further studies.
Conflict of interest statement: The authors have completed and submitted the form translated into Spanish for the declaration of potential conflicts of interest of the International Committee of Medical Journal Editors, and none were reported in relation to this article.