Tag: Endoscopic Third Ventriculostomy

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Why does endoscopic aqueductoplasty fail so frequently?

J Neurosurg 117:141–149, 2012

The aim of this study was to evaluate and compare CSF flow after endoscopic third ventriculostomy (ETV) and endoscopic aqueductoplasty (EAP) in patients presenting with obstructive hydrocephalus caused by aqueductal stenosis.

Methods. In patients harboring aqueductal stenosis who underwent EAP (n = 8), ETV (n = 8), and both ETV and EAP (n = 6), CSF flow through the restored aqueduct and through the ventriculostomy was investigated using cine cardiac-gated phase-contrast MRI. For qualitative evaluation of CSF flow, an in-plane phase-contrast sequence in the midsagittal plane was used. The MR images were displayed in a closed-loop cine format. Quantitative through-plane measurements were performed in the axial plane perpendicular to the aqueduct and/or floor of the third ventricle.

Results. Evaluation revealed significantly higher CSF flow through the ventriculostomies compared with flow through the aqueducts. This was true both when comparing the ETV group with the EAP group and when comparing the flow of the ventriculostomy and aqueduct within the ETV and EAP group. There was no difference in aqueductal CSF flow between patients who underwent EAP alone and patients who underwent ETV and EAP. There was also no difference in ventriculostomy CSF flow between patients who underwent ETV alone and patients who underwent ETV and EAP. Fifty percent of the restored aqueducts became occluded at a mean of 46 months after surgery (range 18–126 months). In contrast, all ETVs remained patent in the mean follow-up period of 110 months after surgery, although 1 patient required shunt placement after 66 months.

Conclusions. Cerebrospinal fluid flow through ventriculostomies is significantly higher than aqueductal CSF flow after EAP. This could be one factor to explain why the reclosure rate of aqueducts after EAP is higher than the reclosure rate of the ventriculostoma after ETV.

 

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Hyponatremia following endoscopic third ventriculostomy

Neurosurg Pediatrics 10:39–43, 2012. http://thejns.org/doi/abs/10.3171/2012.4.PEDS1222

Electrolyte and endocrinological complications of endoscopic third ventriculostomy (ETV) are infrequent but serious events, likely due to transient hypothalamic-pituitary dysfunction. While the incidence of diabetes insipidus is relatively well known, hyponatremia is not often reported. The authors report on a series of 5 patients with post-ETV hyponatremia.

Methods. The records of patients undergoing ETV between 2008 and 2010 were reviewed. All ETVs were performed with a rigid neuroendoscope via a frontal bur hole, standard third ventricle floor blunt perforation, Fogarty catheter dilation, and intermittent normal saline irrigation. Postoperative MR images were evaluated for endoscope tract injury as well as the trajectory from the bur hole center to the fenestration site.

Results. Thirty-two patients (20 male and 12 female) underwent ETV. Their median age was 6 years (range 3 weeks–28 years). Hydrocephalus was most commonly due to nontumoral aqueductal stenosis (43%), nontectal tumor (25%), or tectal glioma (13%). Five patients (16%) had multicystic/loculated hydrocephalus. Five patients (16%) developed hyponatremia between 1 and 8 days following ETV, including 2 patients with seizures (1 of whom was still hospitalized at the time of the seizure and 1 of whom was readmitted as a result of the seizure) and 3 patients who were readmitted because of decline in their condition following routine discharge. No hypothalamic injuries were noted on imaging. Univariate risk factors consisted of age of 2 years or less (p = 0.02), presence of cystic lesions (p = 0.02), and ETV trajectory angle 10° or more from perpendicular (p = 0.001).

Conclusions. Endoscopic third ventriculostomy is a well-tolerated procedure but can result in serious complications. Hyponatremia is rare and may be more likely in younger patients or those with cystic loculations. Patients with altered craniometry may be at particular risk with a rigid endoscopic approach requiring greater manipulation of subforniceal or hypothalamic structures.

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Optimal trajectory of endoscopic third ventriculostomy

J Neurosurg 116:1153–1157, 2012. http://thejns.org/doi/abs/10.3171/2012.2.JNS111287

An optimal entry point for endoscopic third ventriculostomy (ETV) helps protect critical structures from undue manipulation. A commonly accepted ideal entry point is 3 cm from the midline and 1 cm anterior to the coronal suture. The authors of this study reexamine this ideal entry point.

Methods. Trajectory views from MR images or CT scans used for cranial image guidance in 53 patients (age range 3–85 years) who had undergone ETV were retrospectively evaluated. The trajectory from the tuber cinereum back through the center of the foramen of Monro was projected to the surface of the head. The relation of the entry point to the midline and the coronal suture was established.

Results. The mean perpendicular distance from the ideal entry point to the midline was 30.1 ± 7 mm (median 31.9 mm, range 12.5–42.2 mm). The mean perpendicular distance to the coronal suture was 8.9 ± 14.1 mm posterior (median 10.4 mm), ranging from 30.6 mm anterior to 35.8 mm posterior. The entry point tended to be located more posteriorly in women and adults: 5.8 ± 15.4 mm posterior in males versus 13.1 ± 13.2 mm posterior in females (p = 0.08) and 9.1 ± 14.8 mm posterior in adults versus 8.2 ± 11.7 mm posterior in children (p = 0.84).

Conclusions. While the entry point may need to be modified from the ideal trajectory for other anatomical reasons, such as a trajectory through the motor cortex, in general, the authors found that the optimal entry point for ETV was more posterior than previously published and highly variable. Using image guidance or a customized trajectory based on analysis of a patient’s own imaging is highly preferable to using an empirical ideal trajectory.

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Pineal region tumors: an optimal approach for simultaneous endoscopic third ventriculostomy and biopsy

Neurosurg Focus 30 (4):E3, 2011. DOI: 10.3171/2011.2.FOCUS10301

Simultaneous endoscopic third ventriculostomy (ETV) and tumor biopsy is a widely accepted therapeutic and diagnostic procedure for patients with noncommunicating hydrocephalus secondary to a pineal region tumor. Multiple approaches have been advocated, including the use of a steerable fiberoptic or rigid lens endoscope via 1 or 2 trajectories. However, the optimal approach has not been established based on the individual anatomical characteristics of the patient.

 Methods. A retrospective review of patients undergoing simultaneous ETV and tumor biopsy was undertaken. Preoperative MR images were examined to measure the width of the anterior third ventricle and maximal diameters of the tumor, Monro foramen (right), and massa intermedia. The distances between the tumor and massa intermedia, tumor and anterior commissure, midbrain and massa intermedia, and the dorsum sella and anterior commissure were also recorded. Single and dual trajectory approaches were compared using paired t-tests for each parameter.

Results. Over an 8-year interval, 15 patients underwent simultaneous ETV and tumor management. These patients ranged from 6 to 71 years of age (mean 36.7 years); 5 were younger than 18 years of age. Seven were treated using a dual trajectory approach, and 8 were treated using a single trajectory approach. All cases were completed without complications or the need for an additional CSF diversionary procedure within 6 months. The diagnostic yield at biopsy was 86.7%. There were no statistically significant differences between the single and dual trajectory groups for the measured parameters. However, the dual trajectory group demonstrated a larger anterior third ventricular diameter (1.43 vs 1.21 cm, p = 0.29). The single trajectory group trended toward a smaller tumor– anterior commissure interval (2.23 vs 2.51 cm, p = 0.24) and a larger dorsum sella–anterior commissure distance (1.67 vs 1.49 cm, p = 0.28).

Conclusions. These data confirm the safety and diagnostic efficacy of simultaneous ETV and biopsy for tumors of the pineal region. Although no statistically significant differences were seen in the authors’ recorded measurements, several trends suggest a role for a tailored approach to selecting a single or dual trajectory approach when using a rigid endoscope

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Endoscopic Third Ventriculostomy for the Management of Chiari I and Related Hydrocephalus: Outcome and Pathogenetic Implications

Neurosurgery 68:950–956, 2011 DOI: 10.1227/NEU.0b013e318208f1f3

Hydrocephalus affects 7% to 10% of patients with Chiari I malformation (CIM). It can be successfully treated by endoscopic third ventriculostomy (ETV), possibly improving related CIM and syringomyelia.

OBJECTIVE: To confirm the effectiveness of ETV in the management of Chiari-related hydrocephalus and symptoms and to estimate the posterior cranial fossa volume (PCFV) to find the possible reasons for the success or failure of ETV.

METHODS: Fifteen patients (11 children and 4 adults) underwent ETV for hydrocephalus associated with CIM (syringomyelia was present in 6 patients). Preoperative PCFV, posterior fossa brain volume (PFBV), and PFBV/PCFV ratio were calculated in the last 12 patients in the series by a magnetic resonance imaging–based computerized method.

RESULTS: All patients had symptomatic hydrocephalus (mean third ventricle diameter, 14.1 mm). Mean tonsillar ectopia was 12.7 mm. Postoperatively, hydrocephalus symptoms improved in all cases (mean third ventricle diameter, 8.3 mm); signs and symptoms of CIM and syringomyelia resolved or improved in all patients, although the malformation remained radiologically stable in half of the patients (postoperative mean tonsillar ectopia, 8.8 mm). There were no remarkable differences between cases and controls with regard to PCFV and PFBV. The PFBV/PCFV ratio was comparable in pediatric cases and controls but not among adult patients, suggesting a PCF overcrowding in the controls.

CONCLUSION: ETV is an effective treatment for hydrocephalus associated with CIM. It is successful in improving CIM and syringomyelia in patients with no overcrowding (mainly in children) or with reversible overcrowding of the PCF (mainly in adults).

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Neuroendoscopic biopsy of ventricular tumors: a multicentric experience

Neurosurg Focus 30 (4):E2, 2011. DOI: 10.3171/2011.1.FOCUS10326

Although neuroendoscopic biopsy is routinely performed, the safety and validity of this procedure has been studied only in small numbers of patients in single-center reports. The Section of Neuroendoscopy of the Italian Neurosurgical Society invited some of its members to review their own experience, gathering a sufficient number of cases for a wide analysis.

Methods. Retrospective data were collected by 7 centers routinely performing neuroendoscopic biopsies over a period of 10 years. Sixty patients with newly diagnosed intraventricular and paraventricular tumors were included. No patient harboring a colloid cyst was included. Data regarding clinical presentation, neuroimaging findings, operative techniques, pathological diagnosis, postoperative complications, and subsequent therapy were analyzed.

Results. In all patients, a neuroendoscopic tumor biopsy was performed. In 38 patients (64%), obstructive hydrocephalus was present. In addition to the tumor biopsy, 32 patients (53%) underwent endoscopic third ventriculostomy (ETV), and 7 (12%) underwent septum pellucidotomy. Only 2 patients required a ventriculoperitoneal shunt shortly after the endoscopy procedure because ETV was not feasible. The major complication due to the endoscopy procedure was ventricular hemorrhage noted on the postoperative images in 8 cases (13%). Only 2 patients were symptomatic and required medical therapy. Infection occurred in only 1 case, and the other complications were all reversible. In no case did clinically significant sequelae affect the patient’s outcome. Tumor types ranged across the spectrum and included glioma (low- and high-grade [27%]), pure germinoma (15%), pineal parenchymal tumor (12%), primary neuroectodermal tumor (4%), lymphoma (9%), metastasis (4%), craniopharyngioma (6%), and other tumor types (13%). In 10% of patients, the pathological findings were inconclusive. According to diagnosis, specific therapy was performed in 35% of patients: 17% underwent microsurgical removal, and 18% underwent chemotherapy or radiotherapy.

Conclusions. This is one of the largest series confirming the safety and validity of the neuroendoscopic biopsy procedure. Complications were relatively low (about 13%), and they were all reversible. Neuroendoscopic biopsy provided meaningful pathological data in 90% of patients, making subsequent tumor therapy feasible. Cerebrospinal fluid pathways can be restored by ETV or septum pellucidotomy (65%) to control intracranial hypertension. In light of the results obtained, a neuroendoscopic biopsy should be considered a possible alternative to the stereotactic biopsy in the diagnosis and treatment of ventricular or paraventricular tumors. Furthermore, it could be the only surgical procedure necessary for the treatment of selected tumors.

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Endoscopic third ventriculostomy in patients with a diminished prepontine interval

J Neurosurg Pediatrics 5:02050–200540, 2010. DOI: 10.3171/2009.10.PEDS09187

Fenestration of the floor of the third ventricle is vital to the success of endoscopic third ventriculostomy (ETV) in treating patients with noncommunicating hydrocephalus. A generous prepontine interval (PPI) is generally accepted as one anatomical feature that may affect the safety and functionality of ETV. Whether a diminished PPI influences the safety or success of ETV, however, has not been adequately assessed.

Methods: A review was conducted on the last 100 ETV procedures performed by the first author (M.M.S.). From archived preoperative MR imaging studies, the PPI was measured between the dorsum sellae and the basilar artery. For any patient with an interval of ≤1 mm, the technical and functional success of the procedure was recorded. Technical success was defined when a surgically created fenestration was accomplished without patient morbidity. Functional success was defined as the patient not needing any additional CSF diversionary procedure within 3 months after ETV.

Results: In the entire cohort, the PPI ranged from 0 to 9.5 mm (mean 3.2 mm). There were 15 procedures performed in patients with a PPI of ≤1 mm. In all 15 procedures, a fenestration of the tuber cinereum was accomplished without vascular injury or patient morbidity. The ETV was successful in 11 patients (73.3%). All 4 failures occurred in children who had surgery during infancy (mean age 11 months).

Conclusions: Patients with an obliterated or reduced PPI can safely undergo ETV. The functional success rate appears equivalent to historical controls. Most failures in this series may be attributed to other patient characteristics, namely young age at the time of ETV.

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Endoscopic third ventriculostomy for obstructive hydrocephalus in children younger than 6 months of age

Childs Nerv Syst. DOI 10.1007/s00381-009-1019-z

The outcome of endoscopic third ventriculostomy (ETV) is worse in children younger than 2 years old and especially in infants, and controversies still exist whether ETV might be superior to shunt placement in this age group. We retrospectively analyzed the data of 23 patients younger than 6 months of age treated with ETV and assessed its feasibility as a first choice of treatment for hydrocephalus.

Methods: Between 1994 and 2008 in our clinic, 23 patients younger than 6 months having presented with obstructive hydrocephalus were treated endoscopically. The etiology of hydrocephalus was congenital aqueduct stenosis in 11 patients, posthemorrhagic obstruction in six patients, myelomeningocele in two patients, postmeningitis in two patients, Chiari I malformation in one patients, and Dandy Walker variant in one patient. ETV was considered successful when no shunt operation was needed in the patient.

Results: ETV was successful in eight patients with regression of intracranial hypertension. In the remaining 15 patients ventriculoperitoneal shunt implantation was necessary. Total success rate in our group of patients was 34.8%. In patients younger than 3 months of age (n=12), success rate was 25.0%. In patients from 3 to 6 months of age (n=11), success rate was 45.5%. Complication included intraventricular hemorrhage in one patient, meningitis and cerebrospinal fluid leak in one patient, and meningitis in one patient.

Conclusions: Based on our experience, ETV could be the first method of choice for hydrocephalus in children younger than 6 months of age, especially in patients older than 3 months of age.

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Is the routine placement of a CSF reservoir following endoscopic third ventriculostomy justified?

British Journal of Neurosurgery,23:5,521-523. DOI: 10.1080/02688690902980849

Endoscopic third ventriculostomy (ETV) is a well established treatment for selected cases of obstructive hydrocephalus. However, it does carry a significant rate of failure, which can be abrupt and life threatening. The present study analyses the benefits versus the risks of routine CSF reservoir insertion during ETV. Clinical data obtained from the medical records of patients from a single neurosurgical centre who underwent ETV between August 2002 and February 2007 were analysed retrospectively. A total of 34 records were available with follow-up ranging from 3–56 months (Median 26 months) and with patient age range between 6 months – 75 yrs (median 19 years). During this period, one neurosurgeon routinely placed reservoirs in all patients undergoing ETV (n1/434). In all instances of reservoir insertion, Ommaya reservoirs were used. The number of patients in which the reservoir was tapped for diagnostic and/or therapeutic reasons was quantified, and all complications resulting from reservoir placement recorded. ETV success was defined by a lack of subsequent need for cerebrospinal fluid diversion. In total 13 of 34 (38%) reservoirs inserted were tapped at a later date and there were no complications associated with their insertion. Tapping of reservoirs helped determine which patients required subsequent ventriculoperitoneal (VP) shunting. In at least one case reservoir tapping was carried out as an emergency and was a crucial intermediate intervention prior to further surgery. The overall success rate of ETV was 65% (95% CI, 49–81%) with four complications associated with ETV: short-term memory loss, psychosis, and two cases of post-operative seizures. These complications were not attributed to CSF reservoir insertion but the ETV procedure itself. The routine placement of CSF reservoir following ETV thus seems justified with respect to the observed benefits and lack of complications associated with its placement.


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