Endoscopic third ventriculostomy

Ventricular volume changes after successful shunting in hydrocephalic infants

Objectives

Due to increased number of patients suffering from hydrocephalus (HCP) and lack of data concerning volumetric changes after shunting operations, this study aims to assess the volumetric changes in brain ventricles after successful ventriculoperitoneal (VP) shunt surgery in correlation with clinical improvement.

Patient and methods

This study included 20 patients; all of them are below the age of 2 years. All the patients had hydrocephalus, were treated surgically with VP shunts, and have clinically improved over the period of study. We measured the volumetric changes radiologically using the fronto-occipital horn ratio (FOHR) over a period of 6 months postoperatively.

Results

The frontal and occipital horn ratio was calculated in all these patients both pre and postoperatively. There was a significant radiological improvement in the majority of children after the shunt operation. One month postoperatively, the FOHR decreased to about 85% of its preoperative value in average. The FOHR was found to be significantly improving with time over a period of 6 months reaching 63% of its preoperative value.

Conclusion

Successful treatment of HCP in infants via VPS seems to be of benefit in decreasing the ventricular size gradually to a near normal FOHR with clinical improvement.

Comparison of Intracranial Neuroendoscopic Procedures in Children versus Adults

BACKGROUND

The emphasis regarding intracranial neuroendoscopy has been traditionally advocated and focused on the role in pediatric patients, although a significant usage has developed in adult patients. In this study, we examine and contrast the role of predominantly intracranial neuroendoscopy in both a pediatric and adult population with a minimum postprocedure follow-up of 5 years.

METHODS

A retrospective review was conducted for patients in the two hospitals that manage neurosurgical care for Southern Alberta, Canada, undergoing neuroendoscopic surgery between 1994 and 2008. The pediatric group was defined as age ≤17 years and the adult group as age ≥18 years.

RESULTS

A total of 273 patients who underwent a total of 330 procedures with a mean postprocedure follow-up of 12.9 years were identified. There were 161 adult and 112 pediatric patients, and both groups underwent surgery by the same surgeons. The most common procedure was endoscopic third ventriculostomy, accounting for 55% of procedures. One postoperative death occurred in an adult patient. Endoscopic third ventriculostomy success 1-year postprocedure was 81%, with only three late-term failures. Postoperative infection was the most common serious complication (two pediatric/four adult patients). Adult and pediatric patients had similar major complication rates (4.2% vs 5.7%, p=0.547).

CONCLUSIONS

Neuroendoscopy overall had a similar role in both pediatric and adult neurosurgical populations, with the most commonly associated complication being infection. Neuroendoscopy is an important therapeutic modality in the management of appropriate adult patients.

A Novel Protocol of Continuous Navigation Guidance for Endoscopic Third Ventriculostomy

BACKGROUND:

Although considered a standard neurosurgical procedure, endoscopic third ventriculostomy (ETV) is associated with a relatively high complication rate that is predominantly related to malpositioning of the trajectory.

OBJECTIVE:

To develop an advanced navigation protocol for ETV, assess its possible benefits over commonly used ETV trajectories, and apply this protocol during surgery.

METHODS:

After development of our advanced protocol, the imaging data of 59 patients who underwent ETV without navigation guidance was transferred to our navigation software. An individualized endoscope trajectory was created according to our protocol in all cases. This trajectory was compared with 2 standard trajectories, especially with regard to the distance to relevant neuronal structures: a trajectory manually measured on preoperative radiological images, as performed in all 59 cases, and a trajectory resulting from a commonly used fixed coronal burr hole. Subsequently, we applied the protocol in 15 ETVs to assess the feasibility and procedural complications.

RESULTS:

Our individualized trajectory resulted in a significantly greater distance to the margins of the foramen of Monro, and the burr hole was located more posteriorly from the coronal suture in comparison with the standard trajectories. The advanced ETV technique was feasible in all 15 procedures, and no major complications occurred in any procedure. In 1 patient, a fornix contusion without clinical correlation was observed.

CONCLUSION:

Our data indicate that the proposed navigation protocol for ETV optimizes the distance of the endoscope to important neuronal structures. Continuous endoscope and puncture device guidance may further add to the safety of this procedure.

Endoscopic third ventriculostomy: predicting outcome with phase-contrast MR imaging

PURPOSE

To determine whether phase-contrast magnetic resonance (MR) imaging measurements of preoperative cerebral blood and cerebrospinal fluid (CSF) hydrodynamics can be used as a biomarker of response to endoscopic third ventriculostomy (ETV).

MATERIALS AND METHODS

Approval from the local research ethics committee and written informed consent were obtained for this prospective study. Thirteen patients (six female patients, seven male patients; median age, 43 years) with chronic obstructive hydrocephalus, 12 of whom went on to undergo ETV, were imaged with phase-contrast MR imaging at 1.5 T to determine rates of total cerebral blood flow (CBF) and ventriculostomy defect, foramen magnum (FM), and cerebral aqueduct CSF flow. Ten control subjects (10 men; median age, 37 years) were similarly imaged. Correlations between measured values were assessed by means of Pearson correlation coefficients. Measurements were compared between groups with a Mann-Whitney test, and measurements before and after surgical intervention were compared with a Wilcoxon test for paired samples.

RESULTS

Rates of CBF (356 mL . min(-1) +/- 73 [standard deviation] vs 518 mL . min(-1) +/- 79, P < .001) and CSF flow in the FM (17.62 mL . min(-1) +/- 13.12 vs 36.35 mL . min(-1) +/- 8, P < .05) were significantly lower in patients than in control subjects.

CONCLUSION

ETV induces changes in brain volume and CBF that can be predicted by using simple metrics. These pilot results support a formal trial of these techniques in a larger prospective study.

Coexistent intraventricular abnormalities in periventricular giant arachnoid cysts

OBJECT

Arachnoid cysts are congenital lesions that arise during development by splitting of the arachnoid membrane. Large cysts can be adjacent to CSF pathways causing a marked midline shift and hydrocephalus. The association between a large arachnoid cyst and hydrocephalus has been commonly described as being due to a mass effect, but these previous reports have not focused closely on any associated intraventricular abnormalities.

METHODS

Seven patients who were previously treated with a cystoperitoneal shunt presented with shunt failure, hydrocephalus, and/or cyst expansion. All of these patients had giant arachnoid cysts extending to the periventricular region from the original site, which was the sylvian fissure in 4 patients, and the suprasellar cistern, quadrigeminal cistern, and interhemispheric fissure in 1 patient each. Endoscopic exploration of the ventricular system and cyst fenestration was then performed in all patients.

RESULTS

The endoscopic findings were obstruction of the cerebral aqueduct by a membrane not related to the cyst in 5 patients, occlusion of the foramen of Monro in 6, septum pellucidum hypoplasia in 2, and occlusion of the cerebral aqueduct by a quadrigeminal arachnoid cyst in 1. Endoscopic procedures performed were septum pellucidum fenestration and/or foraminoplasty in 5 patients, aqueductoplasty in 2, endoscopic third ventriculostomy in 5, fenestration of the lamina terminalis in 1, and direct cystocisternostomy in 1. After the endoscopic procedure, signs and symptoms of increased intracranial pressure and hydrocephalus improved in all patients, with a reduction in size of the cyst and the ventricle.

CONCLUSIONS

Ventricular abnormalities contributing to hydrocephalus may be associated with arachnoid cysts. These abnormalities may more likely reflect a common origin than a casual relation. Foramen of Monro stenosis and cerebral aqueduct occlusion associated with an arachnoid cyst can be more frequent than has been previously believed. In cases of periventricular giant arachnoid cysts, endoscopic exploration is a good alternative for examining the ventricular system and identifying and treating CSF obstructions caused by and/or related to arachnoid cysts.

LASER-ASSISTED ENDOSCOPIC THIRD VENTRICULOSTOMY

OBJECTIVE

Endoscopic third ventriculostomy is a well-known surgical option in the treatment of noncommunicating hydrocephalus. We studied complications and long-term success in 202 patients to demonstrate the safety and efficacy of laser-assisted endoscopic third ventriculostomy (LA-ETV) using a unique “black” fiber tip/diode laser combination for controlled tissue ablation.

METHODS

We studied 213 LA-ETVs, which were performed in 202 patients. Patients' ages ranged from 2 days to 83 years (mean age, 27 yr). The mean follow-up period for all patients was 2.7 years (range, 2 d to 12 yr). Hydrocephalus was caused by aqueductal stenosis in 65 patients, tumors in 67 patients, hemorrhages in 24 patients, myelomeningoceles in 20 patients, cysts in 15 patients, and other causes in 11 patients. The long-term effectiveness of LA-ETV was studied with Kaplan-Meier analysis.

RESULTS

Technically successful LA-ETVs were accomplished in 196 of the 202 patients (97%). The overall success rate for a functional LA-ETV was 68% at the 2-year follow-up evaluation. LA-ETV was more effective in patients aged 1 year and older (70% success rate) than in younger patients (59% success rate). Success rates were greater in patients with aqueductal stenosis or tumors as compared to other etiologies. Complications occurred in 22 procedures (10.3%). Only one patient (0.5%) experienced a major complication. No surgical mortalities or laser-related complications occurred.

CONCLUSION

This study demonstrates that LA-ETV is a safe and effective procedure that is comparable to other techniques for ETV. LA-ETV is most effective in patients aged 1 year and older and in patients with aqueductal stenosis and tumors, with a low major complication rate.