Endoscopic third ventriculostomy with cystoventricular stent placement in the management of dandy-walker malformation: technical case report of three patients

Developmental Retrocerebellar Cysts: A New Classification for Neuroendoscopic Management and Systematic Review

OBJECTIVE

Posterior fossa cystic malformations are diversely classified with considerable overlap without therapeutic relevance. These cysts posterior to the cerebellum, presenting in children younger than 5 years, are labeled developmental retrocerebellar cysts (DRCCs) under a new classification in relation to neuroendoscopy.

METHODS

DRCC was categorized as type 0 for asymptomatic enlarged cistern magna and was not treated. Among symptomatic cases, cysts with a compressed fourth ventricle were labeled type 1, whereas cysts in continuity with the fourth ventricle were termed type 2. They were further categorized as subtype B if hydrocephalus was greater relative to the cyst, or otherwise as subtype A. The literature was reviewed according to PRISMA guidelines.

RESULTS

There were 13 children aged 3-48 months. Type 1A DRCC was noted in 5 patients, with onset before 6 months, 4 of whom (80%) had intracranial hypertension. All underwent suboccipital endoscopic deroofing and cisternostomy (SEDC), a new technique. Type 1B DRCC was seen in 2 patients, with onset at 8-9 months, who underwent endoscopic third ventriculostomy (ETV) + endoscopic ventriculocystostomy (EVC). Type 2A DRCC was observed in 4 patients, with onset at 5-47 months, who underwent SEDC. Type 2B DRCC was noted in 2 patients, with onset 6-8 months, who underwent ETV. With a mean follow-up of 32 months, all showed clinicoradiologic improvement. The application of our classification to other studies showed ETV/EVC to be successful in only 67% of type 1A DRCC and 72% of type 2A DRCC, compared with 100% efficacy of SEDC in our series.

CONCLUSIONS

This is probably the first ever endoscopic classification of pediatric posterior fossa cyts, elucidating pathophysiology, presentation, and treatment. Patients with type 1 DRCC present early because of extraneous compression. Among patients with type 2 DRCC, posterior fossa compliance determines the degree of hydrocephalus. The newly described SEDC seems more appropriate for types 1A and 2A DRCC. ETV is adequate in type 2B DRCC and effective with EVC in type 1B.

Surgical Management of Isolated Fourth Ventricular Hydrocephalus Associated with Injury to the Guillain-Mollaret Triangle

BACKGROUND

The occurrence of isolated fourth ventricle and injury to the Guillain-Mollaret triangle in the setting of posterior fossa ependymoma represents a new association. In this case report, we discuss the clinical, theoretical, and therapeutic aspects of this problem. We describe a lateral transcerebellar trajectory and shunt valve configuration for safe fourth ventricle shunting in a patient with prior posterior fossa surgery.

CASE DESCRIPTION

A 45-year-old woman underwent subtotal resection of a fourth ventricle ependymoma (World Health Organization grade III) followed by radiation therapy to control the residual tumor. Her course was complicated by a cerebral abscess and subsequent communicating hydrocephalus, for which she received a lateral ventriculoperitoneal shunt. After placement of the lateral ventricle shunt, there was a progressive increase in the volume of the fourth ventricle over the next 2 years, from 2.5 to 12.0 mL. She developed palatal myoclonus, hand incoordination, bilateral foot numbness, and progressive ataxia. Neuroimaging also revealed hypertrophic degeneration of the inferior olivary nuclei bilaterally. The isolated fourth ventricle was treated by a separate fourth ventriculoperitoneal shunt inserted through a lateral transcerebellar trajectory. A programmable variable pressure valve was implemented.

CONCLUSIONS

Development of an isolated fourth ventricle and injury to the Guillain-Mollaret triangle in the setting of fourth ventricular ependymoma is a newly encountered complication. Choice of treatment modality and timing of intervention should be carefully considered on a case-by-case basis. The data presented in this report may assist in the selection of surgical treatment for isolated fourth ventricle.

Aqueduct Stent Placement: Indications, Technique, and Clinical Experience

OBJECTIVE

Complicated hydrocephalus, such as trapped fourth ventricle, is challenging. Aqueduct stent placement is a possible alternative to the conventional multiple shunts approach. This article discusses the indications, techniques, and clinical experiences of aqueduct stent placement.

METHODS

We retrospectively analyzed a series of 10 consecutive patients with hydrocephalus and had aqueduct stent placement between February 2009 and May 2014. The clinical and imaging data were collected and the indications, technique, and clinical experience of aqueduct stent placement were analyzed and discussed.

RESULTS

Among the 10 patients (mean age, 38 years; range, 5 months-69 years), 8 patients harbored an obstructive hydrocephalus caused by aqueductal obstruction. The underlying pathology consisted of intraventricular tumor in 3 patients, intraventricular cysticercosis in 2, and membranous or inflammatory obstruction in 3 patients. Two patients presented with trapped fourth ventricle, which resulted from Dandy-Walker malformation and shunt placement, respectively. Aqueduct stents were placed endoscopically in 8 patients, whereas the other 2 were placed microscopically. There were no deaths due to aqueduct stent placement. Postoperatively, all of the patients showed improvement or resolution of their symptoms. After an average follow-up period of 27 months (range, 1-51 months), recurrence of aqueductal obstruction has not been observed. In 1 patient, there was a complication of transient oculomotor paralysis after aqueduct stent placement. A stent migration was observed in 1 patient after remaining stable for 4 years.

CONCLUSIONS

Aqueduct stent placement is technically feasible and can be useful in selected patients either with endoscopy or open surgery.

Experience of using neuroendoscopy in treatment of noncommunicating hydrocephalus in infants

320 children were operated on for occlusive hydrocephalus for 10 years (2003-2012). Infant patients amounted to 93.4%, of these newborns were 29.2%. An endoscopic technique was used to restore physiological liquor circulation and compensate for hydrocephalus without shunt implantation. The positive outcome was observed in 75% of cases. Occlusion of the subarachnoid space occurred in the other cases, which required a combination of neuroendoscopic intervention and shunt implantation. There were no complications and mortality associated with an operative trauma.

Endoscopic third ventriculostomy in the management of hydrocephalus: Outcome analysis of 168 consecutive procedures

BACKGROUND

Endoscopic third ventriculostomy (ETV) is the treatment of choice for obstructive hydrocephalus, but the outcome is still controversial in terms of age and aetiology.

METHODS

Between 1998 and 2011, 168 consecutive procedures were performed in 164 patients, primarily children (56%<18 years of age and 35%<2 years of age). The causes of obstructive hydrocephalus included tumoural pathology, Chiari malformation, congenital obstruction of the aqueduct, post-infectious and post-haemorrhagic membranes, and ventriculo-peritoneal shunt (VPS) malfunctions. Successful ETV was defined by the resolution of symptoms and the avoidance of a shunt.

RESULTS

ETV was successful in 75.6% of patients, but 19% of the patients required VPS in the first month after ETV, and 5.4% required a VPS more than one month after ETV. Four patients were ultimately submitted for second ETVs. In this series, no major permanent morbidity or mortality was observed.

CONCLUSIONS

ETV is a safe procedure and an effective treatment for obstructive hydrocephalus even following the dysfunction of previous VPSs and in children younger than two years.

Current state and future development of intracranial neuroendoscopic surgery

Since the introduction of the modern, smaller endoscopes in the 1960s, neuroendoscopy has become an expanding field of neurosurgery. Neuroendoscopy reflects the tendency of modern neurosurgery to aim towards minimalism; that is, access and visualization through the narrowest practical corridor and maximum effective action at the target point with minimal disruption of normal tissue. Transventricular neuroendoscopy allows the treatment of several pathologies inside the ventricular system, such as obstructive hydrocephalus and intra-/paraventricular tumors or cysts, often avoiding the implantation of extracranial shunts or more invasive craniotomic approaches. Endoscopic endonasal transphenoidal surgery allows the treatment of pathologies of the sellar and parasellar region, with the advantage of a wider vision of the surgical field, less traumatism of the nasal structures, greater facility in the treatment of possible recurrences and reduced complications. However, an endoscope may be used to assist microsurgery in virtually any kind of neurosurgical procedures (endoscope-assisted microsurgery), particularly in aneurysm and tumor surgery. Basic principles of optical imaging and the physics of optic fibers are discussed, focusing on the neuroendoscope. The three main chapters of neuroendoscopy (transventricular, endonasal transphenoidal and endoscope-assisted microsurgery) are reviewed, concerning operative instruments, surgical procedures, main indications and results.

Ascending transaqueductal cystoventriculoperitoneal shunting in Dandy-Walker malformation: technical note

The optimal treatment for Dandy-Walker malformation is still controversial. Ventriculoperitoneal shunting, cystoperitoneal shunting or combinations are the most common surgical options in the management of this clinical entity. Endoscopic procedures like ventriculocystostomy, 3rd ventriculostomy or endoscopy-assisted shunt surgeries have become the focus of recent publications. We describe a new transcystic endoscopic technique, with the usage of a single ascending transaqueductal shunt catheter with additional holes, whereby both the posterior fossa cyst and supratentorial ventricular compartments are drained effectively. By using this new technique complications associated with combined shunting can be avoided. In addition, by equalizing the pressure within the supra- and infratentorial compartments, the upward or downward herniations associated with single-catheter shunting can be prevented.

Microsurgical third ventriculostomy with stenting in intrinsic brain tumors involving anterior third ventricle

OBJECTIVE

Microsurgical fenestration of the third ventricular floor performed in one session with resection of deep seated tumors has been recently demonstrated as an approach to specifically address the concomitant obstructive hydrocephalus. As with endoscopic third ventriculostomy, occlusion of the stoma may result in progression of the obstructive hydrocephalus. In order to provide reliable communication between the basal cisterns and ventricles, we propose stenting of the stoma in cases of direct surgical approach to deep seated tumors.

METHODS

After performing tumor resection through the anterior transcallosal approach, premamillar and Liliequist's membranes were identified and fenestrated. A silicon stent was inserted into the prepontine cistern through the fenestrated floor of the third ventricle; the stent connected the third and lateral ventricles with the basal cisterns.

RESULTS

Microsurgical ventriculostomy of the third ventricle and stenting of the stoma was performed in 9 patients simultaneously with tumor resection (5 cases), open biopsy (3 cases), or microsurgical dissection of severe adhesions at the level of Monro foramina (1 case). In 7 cases, the third ventricular floor was infiltrated with the tumor and obstruction of the aqueduct persisted after tumor surgery; in 2 patients, high risk of reocclusion at the level of Monro foramen was expected. Stenting of the ventricular system provided patency of the stoma and Monro foramen. None of the patients required a shunt postoperatively. The follow-up time ranged from 3 to 22 months.

CONCLUSION

Microsurgical fenestration of the third ventricle floor combined with stoma stenting can be a viable option for hydrocephalus control.

Hydrocephalus in Dandy-Walker malformation

INTRODUCTION

Even if the first description of Dandy-Walker dates back 1887, difficulty in the establishment of correct diagnosis, especially concerning differential diagnosis with other types of posterior fossa CSF collection, still persists. Further confusion is added by the inclusion, in some classification, of different malformations with different prognosis and therapeutic strategy under the same label of "Dandy-Walker".

METHODS

An extensive literature review concerning embryologic, etiologic, pathogenetic, clinical and neuroradiological aspects has been performed. Therapeutic options, prognosis and intellectual outcome are also reviewed.

CONCLUSION

The correct interpretation of the modern neuroradiologic techniques, including CSF flow MR imaging, may help in identifying a "real" Dandy-Walker malformation. Among therapeutical strategies, single shunting (ventriculo-peritoneal or cyst-peritoneal shunts) appears effective in the control of both ventricle and cyst size. Endoscopic third ventriculostomy may be considered an acceptable alternative, especially in older children, with the aim to reduce the shunt-related problems. Prognosis and intellectual outcome mostly depend on the presence of associated malformations, the degree of vermian malformation and the adequate control of hydrocephalus.

A novel method for stereotactic, endoscope-assisted transtentorial placement of a shunt catheter into symptomatic posterior fossa cysts

OBJECT

Posterior fossa cysts are usually divided into Dandy-Walker malformations, arachnoid cysts, and isolated and/or trapped fourth ventricles. Shunt placement is a mainstay treatment for decompression of these fluid collections when their expansion becomes symptomatic. Although several techniques to drain symptomatic posterior fossa cysts have been described, each method carries its own advantages and disadvantages. This article describes an alternative technique.

METHODS

In 10 patients, the authors used an alternative technique involving stereotactic and endoscopic methods to place a catheter in symptomatic posterior fossa cysts across the tentorium. Discussion of these cases is included, along with a review of various approaches to shunt placement in this region and recommendations regarding the proposed technique.

RESULTS

No patient suffered intracranial hemorrhage related to the procedure and catheter implantation. All 3 patients who underwent placement of a new transtentorial cystoperitoneal shunt and a new ventriculoperitoneal shunt did not suffer any postoperative complication; a decrease in the size of their posterior fossa cysts was evident on CT scans obtained during the 1st postoperative day. Follow-up CT scans demonstrated either stable findings or further interval decrease in the size of their cysts. In 1 patient, the postoperative head CT demonstrated that the transtentorial catheter terminated posterior to the right parietal occipital region without entering the retrocerebellar cyst. This patient underwent a repeat operation for proximal shunt revision, resulting in an acceptable catheter implantation. The patient in Case 8 suffered from a shunt infection and subsequently underwent hardware removal and aqueductoplasty with stent placement. The patient in Case 9 demonstrated a slight increase in fourth ventricle size and was returned to the operating room. Exploration revealed a kink in the tubing connecting the distal limb of the Y connector to the valve. The Y connector was replaced with a T connector, and 1 week later, CT scans exhibited interval decompression of the ventricles. This patient later presented with cranial wound breakdown and an exposed shunt. His shunt hardware was removed and he was treated with antibiotics. He later underwent reimplantation of a lateral ventricular and transtentorial shunt and suffered no other complications during a 3-year follow-up period.

CONCLUSIONS

The introduction of endoscopic and stereotactic techniques has expanded the available treatment possibilities for posterior fossa cysts.

Trapped Fourth Ventricle Phenomenon Following Aneurysm Rupture of the Posterior Circulation

BACKGROUND AND IMPORTANCE

Cerebral ventricular noncommunication has been described in the setting of infection and acutely in the setting of intracranial hemorrhage. We describe the first adult case series of individuals who developed delayed isolated fourth ventricles after rupture of intracranial posterior circulation aneurysms and define treatment modality.

CLINICAL PRESENTATION

A retrospective review was performed of all patients with aneurysms treated at a single institution from 2005 to 2009. Both microsurgical obliteration and endovascular cases were queried. Of 1044 aneurysms treated in this period, 3 patients were identified who required fourth ventricular shunting, for the treatment of the isolated ventricle. All 3 patients underwent microsurgical clip obliteration of their aneurysms and had subsequent frontal approach ventriculoperitoneal cerebrospinal fluid diversion. These patients had no evidence of infection of the cerebrospinal fluid as measured by serial cultures. Subsequently, all 3 patients presented in a delayed fashion with symptoms attributable to a dilated fourth ventricle and syringomyelia or syringobulbia. Either exploration or percutaneous tapping confirmed the function of the supratentorial shunt. These patients then underwent fourth ventriculoperitoneal cerebrospinal fluid diversion by the use of a low-pressure shunt system. The symptoms attributable to the isolated fourth ventricle resolved rapidly in all 3 patients after shunting. This clinical improvement correlated with the fourth ventricular size.

CONCLUSION

Isolated fourth ventricle, in an adult, is a rare phenomenon associated with intracranial posterior circulation aneurysm rupture treated with microsurgical clip obliteration. Fourth ventriculoperitoneal cerebrospinal fluid diversion is effective at resolving the symptoms attributed to the trapped ventricle and associated syrinx.

Endoscopic diagnosis and treatment of far distal obstructive hydrocephalus

PURPOSE

Obstruction of the CSF circulation distal to the fourth ventricle is a rare cause of noncommunicating hydrocephalus. Endoscopic third ventriculostomy (ETV) represents one of the treatment options, but reports of results are rare.

METHODS

Between March 1997 and June 2008, 20 ETVs in 20 patients (mean 32.4 years, range 1 month-79 years) for noncommunicating hydrocephalus distal to the fourth ventricle were undertaken. All patients suffered from severe internal hydrocephalus and typical clinical symptoms. In addition to the standard ETV, a transaqueductal inspection of the posterior fossa with a flexible scope was performed. All patients were prospectively followed.

RESULTS

An ETV was achieved in all patients. It was clinically successful in 15 of 20 patients (75%) with an improvement of 50% (three out of six) of the pediatric and of 83% (12 out of 14) of the adult population. A reduction of ventricle size was found in ten (50%). Five patients (25%) received ventriculoperitoneal shunting. A transaqueductal inspection of the posterior fossa cerebrospinal fluid (CSF) pathways was performed in 16. In the remaining four patients, no inspection with the flexible scope was done. One clinically silent fornix contusion and one CSF fistula which was treated conservatively occurred. There was no permanent morbidity.

CONCLUSIONS

ETV is a successful treatment option in CSF pathway obstructions distal to the fourth ventricle. Although the success rate particularly of the pediatric population appears to be lower than with other indications of obstructive hydrocephalus, a relevant part of the patient population improves after ventriculostomy and shunting can be avoided.

Simultaneous endoscopic third ventriculostomy and ventriculoperitoneal shunt for infantile hydrocephalus

OBJECTIVE

We analyzed a series of consecutive hydrocephalic infants treated with implantation of a ventriculoperitoneal shunt (VPS) and endoscopic third ventriculostomy (ETV) simultaneously.

MATERIALS AND METHODS

Between 1995 and 2006, we treated the 111 hydrocephalic infants. Among those patients, 31 infants underwent VPS and ETV simultaneously, and 45 patients underwent only VPS. The ETV plus VPS group had 17 males and 14 females with a mean age of 6.32 months. The VPS only group consisted of 25 males and 20 females with a mean age of 4.43 months. There was no difference in etiology of hydrocephalus or clinical characteristics between the two groups. We compared shunt effectiveness by calculating the pre- and postoperative ventricular index and shunt failure rates during the follow-up period between the two groups. The follow-up period ranged from 6 to 140 months (mean, 53.23 months) in the ETV plus VPS group and from 6 to 148 months (mean, 75.98 months) in the VPS only group. The success rate was 83.9% (26 of 31) in the ETV plus VPS group and 68.9% (31 of 45) in the VPS only group. There were three infections and two shunt obstructions in the ETV plus VPS group versus eight obstructions, five infections, and one overdrainage in the VPS group. The preoperative and postoperative ventricular ratio of both groups showed statistically significant change (P < 0.000).

CONCLUSION

This simultaneous procedure could be the first choice of action for the hydrocephalic patients less than 1 year old.

Treatment options for Dandy-Walker malformation

OBJECT

The aim of this study was to assess the efficacy of various treatment options available for children with Dandy-Walker malformation (DWM) and to evaluate the role of endoscopic procedures in the treatment of this disorder.

METHODS

The authors conducted a retrospective review of 72 children who underwent surgical treatment for DWM during a 16-year period. All patients underwent computed tomography scanning, and 26 underwent magnetic resonance (MR) imaging. The initial surgical treatment included ventriculoperitoneal (VP) shunt placement in 21 patients, cystoperitoneal (CP) shunt placement in 24, and combined VP and CP shunt insertion in three. Twenty-one patients underwent endoscopic procedures (endoscopic third ventriculostomy [ETV] alone in 16 patients, ETV with aqueductal stent placement in three, and ETV with fenestration of the occluding membrane in two). Three patients underwent membrane excision via a posterior fossa craniectomy. In the 26 patients who had undergone preoperative MR imaging, aqueductal patency was noted in 23 and aqueductal obstruction in three. These three patients underwent placement of a stent from the third ventricle to the posterior fossa cyst in addition to the ETV procedure. During the follow-up period, 12 patients with a CP shunt and four with a VP shunt experienced shunt malfunctions that required revision. Four patients with a CP shunt also required placement of a VP shunt. In addition, five of the 21 ETVs failed, requiring VP shunt insertion. A reduction in ventricle size noted on postoperative images occurred more frequently in patients with a VP shunt, whereas a reduction in cyst size was more appreciable in patients with a CP shunt. Successful ETV resulted in a slight decrease in ventricle size and varying degrees of reduction in cyst size.

CONCLUSIONS

Endoscopic procedures may be considered an acceptable alternative in children with DWM. The authors propose a treatment protocol based on preoperative MR imaging findings of associated aqueductal stenosis.

CT fluoroscopy: novel application for the treatment of ventricular pathologies

INTRODUCTION

Recent advances in multidetector CT imaging (MDCT) provide real-time "fluoroscopic-like" capabilities with excellent spatial resolution. MDCT fluoroscopy expands our ability to perform image-guided interventions in anatomically complex locations. Although MDCT fluoroscopy is currently used at our institution for a variety of procedures ranging from spinal nerve blocks to RFA ablation, we believe these same techniques can be used to navigate within the ventricles of the central nervous system to treat conditions requiring placement of intraventricular catheters, depth electrodes, or potentially stents for the relief of CSF outlet obstruction.

METHODS

Using three fresh, unfrozen human cadavers, we studied the feasibility of using MDCT fluoroscopy for intraventricular catheter placement and to stent the aqueduct of Sylvius.

RESULTS

The ventricles were entered via a single needle pass and catheters were placed over the wire. Contrast agent was then injected to visualize the distribution. To stent the aqueduct of Sylvius, a wire was passed into the 4th ventricle and a coronary stent was then inserted over the wire and deployed.

CONCLUSION

Based on our success with these procedures, we believe this technique can be used to limit complications and improve efficacy of a number of neurosurgical procedures.

Surgical treatment of 13 pediatric patients with Dandy-Walker syndrome

We present our experience with the treatment of 13 patients with Dandy-Walker syndrome. The common presenting symptom and associated central nervous system anomaly were enlargement of head and occipital encephalocele, respectively. Eleven out of 13 patients were treated surgically after stabilization of systemic medical status. Two patients could not be operated because of poor medical condition. In 6 patients with an opened passage between posterior fossa cyst and lateral ventricle, cystoperitoneal shunt system with medium pressure valve was the treatment of choice. In 5 patients with no relation between cyst and ventricle, cystoperitoneal and ventriculoperitoneal shunting with 'Y' connectors were applied separately. Another patient with a shunt infection was treated by shunt system renewal combined with parenteral antibiotics. One patient died 7 months after the operation due to recurrent meningitis.

Endoscopic third ventriculostomy

Among patients with idopathic aqueductal stenosis or impedance of cerebrospinal fluid (CSF) flow in the posterior fossa due to tumour, endoscopic fenestration of the floor of the third ventricle creates an alternative route for CSF flow to the subarachnoid space via the prepeduncular cistern. By reestablishing CSF flow, this procedure dissipates any pressure gradient on midline structures. This may obviate the need for traditional CSF shunt diversion techniques in such settings. Currently, endoscopic third ventriculostomy is indicated in approximately 25% of patients with hydrocephalus and can be performed instead of shunt placement. Appropriate patients are those with aqueductal stenosis (10%), obstructive tumours (10%), and obstructive cysts (5%). Additional recent data suggest the favorability of third ventriculostomy over shunt implantation in additional patient cohorts. Operative technique is discussed.

Late rapid deterioration after endoscopic third ventriculostomy: additional cases and review of the literature

OBJECT

Late rapid deterioration after endoscopic third ventriculostomy (ETV) is a rare complication. The authors previously reported three deaths from three centers. Three other deaths and a patient who experienced rapid deterioration have also been reported. Following the death at the University of Toronto of an additional patient who underwent surgery elsewhere, they canvassed pediatric neurosurgeons in North America, Europe, Australia, and Asia for additional cases.

METHODS

An email was sent to the members of the Canadian Congress of Neurological Sciences who are pediatric neurosurgeons, to the pediatric neurosurgery email list of the American Association of Neurological Surgeons, to the email list of the International Society for Pediatric Neurosurgery, and to designated neurosurgeons in the United Kingdom, France, Japan, Korea, Taiwan, and Australia, who in turn contacted pediatric neurosurgeons in their countries. A data form was provided, and data from previously reported cases were extracted. Nine additional cases were identified, and the results were collated with those of the seven cases previously reported. Patient age at surgery ranged from 2 days to 13 years (mean 7.6 years). The most common causes of hydrocephalus were aqueductal stenosis in 50% of patients and tectal glioma in 25% of patients. The time to treatment failure ranged from 5 weeks to 7.8 years (mean 2.5 years). Thirteen patients died, one patient was in a vegetative state, one patient was mildly disabled, and one patient whose condition deteriorated outside the operating room was alive and well. In the 13 patients in whom the ventriculostomy site was visualized at autopsy or repeated endoscopy, the ventriculostomy was shown to be occluded.

CONCLUSIONS

Late rapid deterioration is a rare but lethal complication of ETV. The mechanism is unclear, but deterioration can occur long after the ETV becomes occluded. Patients and caregivers should be counseled regarding this potential complication. An indwelling ventricular access device is an option for patients undergoing ETV.

Endoscopic third ventriculostomy in the treatment of hydrocephalus in pediatric patients

Advances in surgical instrumentation and technique have lead to an extensive use of endoscopic third ventriculostomy in the management of pediatric hydrocephalus. The aim of this work was to point out the leading aspects related to this technique. After a review of the history, which is now almost one century last, the analysis of the endoscopic ventricular anatomy is aimed to detail normal findings and possible anatomic variations which might influence the correct conclusion of the procedure. The overview of modern endoscopic instrumentation helps to understand the technical improvements that have contributed to significantly reduce the operative invasiveness. Indications are analysed from a pathogenetic standpoint with the intent to better understand the results reported in the literature. A further part of the paper is dedicated to the neuroradiological and clinical means of outcome evaluation, which are still a matter of debate. Finally a review of transient and permanent surgical complications is performed looking at their occurrence in different hydrocephalus etiologies.

Endoscopic third ventriculostomy in adult patients

Endoscopic third ventriculostomy (ETV) has gained popularity and has become the treatment of choice for certain pediatric and adult hydrocephalic conditions. The authors report their experience with 36 adult patients and evaluate the long-term outcome and safety of ETV. They discuss several improvements to the surgical techniques that they have developed based on their experience, including the use of intraoperative Doppler imaging before fenestration to trace the location of vessels underlying the floor of the third ventricle. They also report the use of a Rickham reservoir and endoventricular stent in selected cases and discuss the indications for their use. In cases of obstructive hydrocephalus due to congenital or acquired aqueductal stenosis in adults, the success rate of ETV in avoidance of shunt placement is 72%. Twenty-two percent of the patients in this series in whom ETV was initially successful later experienced closure of the fenestration and recurrent symptoms at a mean interval of 3.75 years. Thus, in patients who undergo this treatment, long-term periodic follow-up review should be performed.

Endoscopic transtentorial ventriculocystostomy and cystoventriculoperitoneal shunt in a neonate with Dandy-Walker malformation and associated aqueductal obstruction

OBJECTIVE

Shunting of the lateral ventricle and the posterior fossa cyst is the advocated surgical therapy for children with Dandy-Walker malformation (DWM) and associated aqueductal obstruction. The high rate of complications of combined shunting stimulated the authors to search for an alternative surgical solution.

CLINICAL PRESENTATION/INTERVENTION

After transtentorial endoscopic ventriculocystostomy, a cystoventricular catheter, connected to a peritoneal shunt, was placed in a neonate with DWM and associated aqueductal obstruction. Immediately prior to ventriculocystostomy, the presence of a blocked third ventricular outflow was reconfirmed by contrast medium injection. Neuronavigation was required to define the surgical path from the lateral ventricle through the tentorium and the overlying small rim of brain parenchyma into the posterior fossa cyst. The postoperative clinical course was uneventful with radiologically proven reduction of the size of the ventricular system and the cyst.

CONCLUSION

Cystoventriculoperitoneal shunt placement after transtentorial endoscopic ventriculostomy is a surgical alternative in very young children with DWM and associated aqueductal obstruction.

Endoscopic, single-catheter treatment of Dandy-Walker syndrome hydrocephalus: technical case report and review of treatment options

Optimal treatment for hydrocephalus related to Dandy-Walker syndrome (DWS) remains elusive. Patients with DWS-related hydrocephalus often require combinations of shunting systems to effectively drain both the supratentorial ventricles and posterior fossa cyst. We describe an endoscopic technique, whereby a frontally placed, single-catheter shunting system effectively drained the supratentorial and infratentorial compartments. This reduces the complexity and potential risk associated with the combined shunting systems required by so many with DWS-related hydrocephalus.

Endoscopic third ventriculostomy for obstructive hydrocephalus

The indications for neuroendoscopy are not only constantly increasing, but even the currently accepted indications are constantly being adjusted and tailored. This is also true for one of the most frequently used neuroendoscopic procedures, the endoscopic 3rd ventriculostomy (ETV) for obstructive hydrocephalus. ETV has gained popularity and widespread acceptance during the past few years, but little attention has been paid to the techniques of the procedure. After a short introduction describing the history of ETV, an overview is given of all the different techniques that have been and still are employed to open the floor of the 3rd ventricle. The spectrum of indications for ETV has been widely enlarged over the last years. Initially, the use of this procedure was restricted to patients older than 2 years, to patients with an obvious triventricular hydrocephalus, and to those with a bulging, translucent floor of the 3rd ventricle. Nowadays, indications include all kinds of obstructive hydrocephalus but also communicating forms of hydrocephalus. The results of endoscopic procedures in treating these pathologies are given under special consideration of shunt technologies. In summary, from the review of the publications since the first ETV performed by Mixter in 1923, this technique is the treatment of choice for obstructive hydrocephalus caused by different etiologies and is an alternative to cerebrospinal fluid shunt application.

Endoscopic and stereotactic neurosurgery

PURPOSE OF REVIEW

Review of the anesthetic considerations for neuroendoscopy and stereotactic procedures.

RECENT FINDINGS

Minimally invasive procedures are increasingly applied in novel ways in the diagnosis and treatment of neurological pathologies. Endoscopic third ventriculostomy, endoscopic shunt revisions and drainage of intraventricular hematoma using a neuroendoscope have become routine neurosurgical procedures. Stereotaxis has expanded its scope from simple brain biopsy to functional neurosurgery and psychiatry. While these procedures are 'minimally invasive', perioperative critical events may still occur.

SUMMARY

Vigilance in preoperative assessment and intraoperative monitoring is essential in minimizing perioperative morbidity and mortality in patients undergoing neuroendoscopic and stereotactic procedures.

Management strategies for treatment of the trapped fourth ventricle

BACKGROUND

An isolated or trapped fourth ventricle (TFV) is an occasional, serious sequela of hemorrhagic, infectious, or inflammatory conditions of the central nervous system. The TFV usually occurs after successful shunting of the lateral ventricles. It may be heralded by delayed clinical deterioration after an initial period of symptomatic improvement. The typical clinical findings suggest an expanding posterior fossa mass lesion. Surgical treatments include CSF diversionary procedures as well as open and endoscopic approaches. Complications related to the treatment of the TFV are common and relate to catheter obstruction and cranial nerve or brainstem dysfunction.

METHODS

The author reviews the clinical features, pathophysiology, and available treatment options for the TFV, with special reference to complication avoidance and advances in ventriculoscopy and frameless stereotaxy.

CONCLUSIONS

Treatment of the TFV remains a formidable challenge. However, prompt recognition and intervention may aid in the preservation of life and neurological function.