Complications of endoscopic third ventriculostomy

Hydrocephalus: A neuropsychological and theoretical primer

Hydrocephalus is a common neurological condition, the hallmark feature of which is an excess in production, or accumulation, of cerebrospinal fluid in the ventricles. Although it is associated with diffuse damage to paraventricular brain areas, patients are broadly typified by a particular pattern of cognitive impairments that include deficits in working memory, attention, and spatial abilities. There have, however, been relatively few neuropsychological accounts of the condition. Moreover, theories of the relationship between aetiology and impairment appear to have emerged in isolation of each other, and proffer fundamentally different accounts. In this primer, we aim to provide a comprehensive and contemporary overview of hydrocephalus for the neuropsychologist, covering cognitive sequelae and theoretical interpretations of their origins. We review clinical and neuropsychological assays of cognitive profiles, along with the few studies that have addressed more integrative behaviours. In particular, we explore the distinction between congenital or early-onset hydrocephalus with a normal-pressure variant that can be acquired later in life. The relationship between these two populations is a singularly interesting one in neuropsychology since it can allow for the examination of typical and atypical developmental trajectories, and their interaction with chronic and acute impairment, within the same broad neurological condition. We reflect on the ramifications of this for our subject and suggest avenues for future research.

Comparative Outcome Analysis of Endoscopic Third Ventriculostomy and Ventriculoperitoneal Shunt Surgery in Pediatric Hydrocephalus: An Experience of a Tertiary Care Center

Background  Endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunt surgery (VPS) are used for the surgical management of pediatric hydrocephalus. There is controversy regarding the safety and efficacy of these procedures according to age, etiologies, and type of hydrocephalus.

Objective  The purpose of this study was to compare the outcomes and complications of ETV and VPS in pediatric hydrocephalus and to evaluate the better procedure.

Material and Methods  We retrospectively analyzed the pediatric hydrocephalus cases that were operated by ETV and VPS at our department from June 2016 to June 2019. Data were analyzed with respect to the etiology of hydrocephalus, age, and gender of the patients. We compared the outcomes (success and failure) depending on age at surgery, etiology, and type of hydrocephalus, complications at 12 months of follow-up. Fisher's exact test and chi-square test were applied to test the significance of difference.

Results  There were 195 pediatric hydrocephalus cases, which were operated by ETV ( n  = 43; 22.05%) and VPS ( n  = 152; 77.95%). The mean age of the cases was 53.63 ± 60.24 (ranged 0.5–204 months) in the ETV group and 53.44 ± 54.10 (ranged 0.3–210 months) in the VPS group. The male-to-female ratio was 1.41:1 in the ETV group and 1.21: 1 in the VPS group. Overall, ETV had successful outcomes in 30(69.77%) cases and VPS in 102(67.11%) cases at 12 months of follow-up. The complication rates were found in 7 (16.28%) cases in the ETV group and 38 (25.0%) cases in the VPS group. At initial 0.5 months of follow-up, ETV required revisions in 6 (13.95%) cases and VPS in 15 (9.87%) cases.

Conclusion  Although the success and failure of both the procedure vary according to the age at surgery, etiology and type of hydrocephalus, and complications, and failure rates on follow-up, there were no statistically significant differences between the two surgical groups in respect to these variables.

Analysis of complications in intraventricular neuroendoscopy in children: proposal for a standardization system

Although intraventricular neuroendoscopy is considered a minimally invasive technique with good results, there is nevertheless a risk of developing certain complications. As no agreement apparently exists concerning the classification of these complications, we aim to propose a form of classification based on the results of our series, comparing them with recent publications. We undertook a retrospective study of 170 children who underwent intraventricular neuroendoscopy between 2003 and September 2020 at our center. Data were recorded on demographic and clinical variables: age, gender, presenting symptoms, etiology, number of procedures, type of procedure, and complications. Complications were divided into two main groups, intraoperative and postoperative, and in subgroups. The intraoperative complications included one group of systemic alterations and another group of surgical problems. The postoperative complications were divided into six groups: systemic, neurologic, hormone, fluid, hemorrhagic and death. A total of 202 neuroendoscopic procedures were performed in 170 children. The mean age at first surgery was 71 months (22-122). The most common etiology of the hydrocephalus was intraventricular tumors (32.9%), followed by aqueductal stenosis (13.5%). The most usual presenting sign was intracranial hypertension. The procedure most used was third ventriculostomy (62.9%). During the procedures, we experienced 5 surgical intraoperative complications (2.47% per procedure). In the postoperative period, there were 23.7% systemic complications per procedure, 12.87% neurologic, 8.41% hormone, 10.9% fluid, 0.5% hemorrhagic, and 0.99% for postoperative death. The rate of complications associated with intraventricular neuroendoscopy was similar in our series to those already published. Comparative studies require standardization for the analysis of neuroendoscopic complications.

Efficacy and safety of flexible versus rigid endoscopic third ventriculostomy in pediatric and adult populations: a systematic review and meta-analysis

Endoscopic third ventriculostomy (ETV) is a well-established surgical procedure for hydrocephalus treatment, but there is sparse evidence on the optimal choice between flexible and rigid approaches. A meta-analysis was conducted to compare efficacy and safety profiles of both techniques in pediatrics and adults. A comprehensive search was conducted on PubMED, EMBASE, and Cochrane until 11/10/2019. Efficacy was evaluated comparing incidence of ETV failure, while safety was defined by the incidence of perioperative complications, intraoperative bleedings, and deaths. Random-effects models were used to pool the incidence. Out of 1365 studies, 46 case series were meta-analyzed, yielding 821 patients who underwent flexible ETV and 2918 who underwent rigid ETV, with an age range of [5 days–87 years]. Although flexible ETV had a higher incidence of failure in adults (flexible: 54%, 95%CI: 22–82% vs rigid: 20%, 95%CI: 22–82%) possibly due to confounding due to etiology in adults treated with flexible, a smaller difference was seen in pediatrics (flexible: 36%, pediatric: 32%). Safety profiles were acceptable for both techniques, with a certain degree of variability for complications (flexible 2%, rigid 18%) and death (flexible 1%, rigid 3%) in pediatrics as well as complications (rigid 9%, flexible 13%), death (flexible 4%, rigid 6%) and intra-operative bleeding events (rigid 6%, flexible 8%) in adults. No clear superiority in efficacy could be depicted between flexible and rigid ETV for hydrocephalus treatment. Safety profiles varied by age but were acceptable for both techniques. Well-designed comparative studies are needed to assess the optimal endoscopic treatment option for hydrocephalus.

Frame-Based Stereotactic Endoscopic Third Ventriculostomy-Toward Improved Precision and Minimizing Morbidities

BACKGROUND

Endoscopic third ventriculostomy (ETV) is a widely accepted treatment for obstructive hydrocephalus. For most practitioners, this procedure will be performed without navigation guidance. Without such guidance, the complications associated with the procedure have ranged from 1% to 8%. We hypothesized that the discrepancy between the surface bony anatomy and internal cranial anatomy contributes to the morbidities associated with ETV. We tested this hypothesis by comparing the position of the entry point defined by the classic Kocher's point relative to the ideal entry point that would result in no manipulation of the endoscope defined by frame-based stereotaxis.

METHODS

The cranial computed tomography scan of 58 patients who had undergone frame-based stereotactic ETV was reformatted into 3-dimensional renderings. The location of this entry point was compared with the Kocher point, as determined by the external bony anatomy.

RESULTS

Overall, >70% of the burr holes that provided an ideal trajectory to the third ventricle were ≥0.5 cm from the Kocher point in both the sagittal and the coronal planes. Median deviations of 0.74 and 0.81 cm in the coronal (P < 0.01) and sagittal (P < 0.0001) planes were observed.

CONCLUSION

The use of stereotactic endoscopic techniques increase the safety of third ventriculostomy by adding precision and reducing otherwise unnecessary surgical maneuvering.

Development and evaluation of a craniocerebral model with tactile-realistic feature and intracranial pressure for neurosurgical training

Objective

In this article, a craniocerebral model is introduced for neurosurgical training, which is patient-specific, tactile-realistic, and with adjustable intracranial pressure.

Methods

The patient-specific feature is achieved by modeling from CT scans and magnetic resonance images (MRI). The brain tissue model is built by the hydrogel casting technique, while scalp, skull, vasculature, and lateral ventricles are all-in-one fabricated by three-dimensional (3D) printing. A closed-loop system is integrated to monitor and control the intracranial pressure. 3D measurements, mechanical tests, and simulated external ventricular drain (EVD) placement procedures are conducted on the model.

Results

A neurosurgical training model is completed with high accuracy (mean deviation 0.36 mm). The hydrogel brain tissue has a stiffness more similar to that of a real brain than the common 3D printed materials. The elasticity modulus of hydrogel brain tissue model is E=25.71 kPa, compared with our softest 3D printed material with E=1.14×103 kPa. Ten experienced surgeons rate the tactile realness of the neurosurgical training model at an average point of 4.25 on a scale from 1 (strongly negative) to 5 (strongly positive). The neurosurgical training model is also rated to be realistic in size (4.82), anatomy (4.70), and effective as an aid to improve blind EVD placement skills (4.65).

Conclusions

The neurosurgical training model can provide trainee surgeons with realistic experience in both tactile feedbacks and craniocerebral anatomy, improving their surgical skills.

The 50 most cited publications in endoscopic third ventriculostomy: a bibliometric analysis

OBJECTIVEAlthough endoscopic third ventriculostomy (ETV) for the treatment of hydrocephalus was introduced in 1923, the method was relegated to the sidelines in favor of extracranial techniques. Since the 1990s to the beginning of the current century, however, ETV has undergone a remarkable resurgence to become the first-line treatment for obstructive hydrocephalus, and for some groups, the procedure has been applied for communicating hydrocephalus as well. In the present study, the authors identified the top 50 cited ETV works. These articles represent works of significance that document current practices and provide guidance for future inquiry.METHODSThe top 50 cited articles pertaining to ETV were identified using bibliometric data obtained with the Harzing's Publish or Perish software search engine. These high-impact works were evaluated for publication properties including year, country of authorship, category, and journal.RESULTSThe top 50 works were cited an average of 141.02 times with a mean of 9.45 citations per year. Articles published in 2005 were the most numerous in the top 50 group. These top articles were most frequently published in the Journal of Neurosurgery: Pediatrics. Most of the articles were clinical studies reporting on patients in the pediatric age group. The country of most authorship was the US, although many other countries were among the top 50 works.CONCLUSIONSThe present report discusses the bibliometric analysis of the top 50 ETV articles. This list may be useful to those interested in the progress and current status of this procedure.

Robot-assisted endoscopic third ventriculostomy: institutional experience in 9 patients

OBJECTIVE The endoscopic third ventriculostomy (ETV) is an established and effective treatment for obstructive hydrocephalus. In its most common application, surgeons plan their entry point and the endoscope trajectory for the procedure based on anatomical landmarks, then control the endoscope freehand. Recent studies report an incidence of neural injuries as high as 16.6% of all ETVs performed in North America. The authors have introduced the ROSA system to their ETV procedure to stereotactically optimize endoscope trajectories, to reduce risk of traction on neural structures by the endoscope, and to provide a stable mechanical holder of the endoscope. Here, they present their series in which the ROSA system was used for ETVs. METHODS At the authors' institution, they performed ETVs with the ROSA system in 9 consecutive patients within an 8-month period. Patients had to have a favorable expected response to ETV (ETV Success Score ≥ 70) with no additional endoscopic procedures (e.g., choroid plexus cauterization, septum pellucidum fenestration). The modality of image registration (CT, MRI, surface mapping, or bone fiducials) was dependent on the case. RESULTS Nine pediatric patients with an age range of 1.5 to 16 years, 4 girls and 5 boys, with ETV Success Scores ranging from 70 to 90, underwent successful ETV surgery with the ROSA system within an 8-month period. Their intracranial pathologies included tectal tumors (n = 3), communicating hydrocephalus from hemorrhage or meningeal disease (n = 2), congenital aqueductal stenosis (n = 1), compressive porencephalic cyst (n = 1), Chiari I malformation (n = 1), and pineal region mass (n = 1). Robotic assistance was limited to the ventricular access in the first 2 procedures, but was used for the entirety of the procedure for the following 7 cases. Four of these cases were combined with another procedural objective (3 stereotactic tectal mass biopsies, 1 Chiari decompression). A learning curve was observed with each subsequent surgery as registration and surgical times became shorter and more efficient. All patients had complete resolution of their preprocedural symptoms. There were no complications. CONCLUSIONS The ROSA system provides a stable, precise, and minimally invasive approach to ETVs.

Anesthesia for Endoscopic Third Ventriculostomy in Children

Neuroendoscopy has established itself as a routine neurosurgical procedure in pediatric population. To have an uneventful smooth perioperative course, it is important for anesthesiologist to know about the key steps, possible complications, and specific anesthetic requirements. Among neuroendoscopies, endoscopic third ventriculostomy is the commonly performed one.

Outcomes of endoscopic third ventriculostomy in adults

Endoscopic third ventriculostomy (ETV) is an alternative to ventriculoperitoneal shunting for treatment of hydrocephalus. Studies have reported favorable outcomes for up to three-quarters of adult patients. We performed the first ETV outcomes study using an administrative claims database, examining current practice for adult patients in the United States. We interrogated the Truven Health MarketScan® database for Current Procedural Terminology codes corresponding to ETV and ventriculoperitoneal shunt from 2003- to 2011, including patients over 18years and data from initial and subsequent hospitalizations. ETV failure was defined as any subsequent ETV or shunt procedure. Five hundred twenty-five patients underwent ETV with 6months minimum follow-up. Mean age was 45.9years (range: 18-86years). Mean follow-up was 2.2years (SD: 1.6years, range: 0.5-8.4years). Etiology of hydrocephalus was 21.3% tumor, 9.0% congenital/aqueductal stenosis, 15.8% hemorrhage, and 53.9% others. ETV was successful in 74.7% of patients. Of 133 who failed, 25 had repeat ETV; 108 had shunt placement. Longer length of stay for index surgery was associated with higher risk of failure (hazard ratio (HR): 1.03, p<0.001), as was history of previous shunt (HR: 2.45, p<0.001). Among patients with repeat surgeries, median time to failure was 25days. This study represents a longitudinal analysis of nationwide ETV practice over 9years. Success rate in this large cohort is similar to that published by other single-center retrospective studies. Age and geographic variation may be associated with surgeon choice of ETV or shunt placement after failure of the initial ETV.

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.

Subdural hematoma after endoscopic third ventriculostomy: Struggling against the Laplace law

BACKGROUND

Endoscopic third ventriculostomy (ETV) is an ideal treatment for obstructive hydrocephalus. Although ETV is a safe procedure, several complications related to this procedure have been reported in the literature. We present a rare case of late onset symptomatic bilateral subdural hematoma after an uneventful ETV that proved particularly difficult to solve.

CASE DESCRIPTION

A 61-year-old male patient presented in our neurosurgery department three months after ETV (aqueductal stenosis) with progressive headaches and anomic aphasia. The MRI revealed bilateral chronic subdural hematomas (chSDH). They were treated via a burr hole evacuation, subduroperitoneal and external subdural drains proving to be refractory to the first two strategies. Postoperatively, his headaches improved. At the last follow-up the patient's status remains improved and there is no radiological evidence of significant residual collections.

CONCLUSION

This case confirms that chSDH formation is a rare possible complication following ETV even in the presence of a normal early postoperative image. Patients should be followed-up more closely for possible subdural collection formation. In the cases of very long-term hydrocephalus with a thin cerebral mantle, brain elastic properties are likely to be altered. As there is no possibility to close the internal shunt, the stoma, we advocate external subdural drainage to reinflate the brain, in the first intention or at least after an initial failed burr hole evacuation.

Development and content validation of performance assessments for endoscopic third ventriculostomy

PURPOSE

This study aims to develop and establish the content validity of multiple expert rating instruments to assess performance in endoscopic third ventriculostomy (ETV), collectively called the Neuro-Endoscopic Ventriculostomy Assessment Tool (NEVAT).

METHODS

The important aspects of ETV were identified through a review of current literature, ETV videos, and discussion with neurosurgeons, fellows, and residents. Three assessment measures were subsequently developed: a procedure-specific checklist (CL), a CL of surgical errors, and a global rating scale (GRS). Neurosurgeons from various countries, all identified as experts in ETV, were then invited to participate in a modified Delphi survey to establish the content validity of these instruments. In each Delphi round, experts rated their agreement including each procedural step, error, and GRS item in the respective instruments on a 5-point Likert scale.

RESULTS

Seventeen experts agreed to participate in the study and completed all Delphi rounds. After item generation, a total of 27 procedural CL items, 26 error CL items, and 9 GRS items were posed to Delphi panelists for rating. An additional 17 procedural CL items, 12 error CL items, and 1 GRS item were added by panelists. After three rounds, strong consensus (>80% agreement) was achieved on 35 procedural CL items, 29 error CL items, and 10 GRS items. Moderate consensus (50-80% agreement) was achieved on an additional 7 procedural CL items and 1 error CL item. The final procedural and error checklist contained 42 and 30 items, respectively (divided into setup, exposure, navigation, ventriculostomy, and closure). The final GRS contained 10 items.

CONCLUSIONS

We have established the content validity of three ETV assessment measures by iterative consensus of an international expert panel. Each measure provides unique assessment information and thus can be used individually or in combination, depending on the characteristics of the learner and the purpose of the assessment. These instruments must now be evaluated in both the simulated and operative settings, to determine their construct validity and reliability. Ultimately, the measures contained in the NEVAT may prove suitable for formative assessment during ETV training and potentially as summative assessment measures during certification.

Small size craniotomy in endoscopic procedures: Technique and advantages

BACKGROUND

Endoscopic procedure has been known as the method of choice for treatment of hydrocephalus with 8.5% complication rate. It seems that good dural closure, reconstructing bone defect and perfect pericranium suturing can decrease the wound complications. Here, we describe the method of minicraniotomy instead of the burr hole in the endoscopic procedure.

MATERIALS AND METHODS

A case-control study regarding the cranial opening for endoscopic surgery was done in 45 patients of <12 months age; 15 patients in case group for minicraniotomy and 30 infants as control group for burr hole. They were followed at least 1-month for complications including cerebrospinal fluid collection, wound dehiscence, wound infection, and meningitis.

RESULT

Patients were between 1 and 11 months. Hydrocephalus (73%) was the most common etiology for endoscopic surgery in this series, followed by the arachnoid cyst (20%). Two patients in the case group and eight in control group developed complications. Meningitis was found in one infant in the control group. Despite less complications in the case group the difference between two cohorts was not statistically significant.

CONCLUSION

Minicraniotomy with providing more space in comparison to burr hole makes dural closure possible. It provides a small bone flap that can be replaced inside the bone defect. In spite of nonsignificant statistical difference between two groups regarding complication rate, we found less wound complications with minicraniotomy. Therefore, we advise this technique for the endoscopic procedure and propose minicraniotomy even in the older population to provide better dural opening, watertight dural closure and reconstructing the bone defect.

[Endoscopic ventriculocisternostomy complications in 108 hydrocephalic patients]

OBJECTIVES

Several reports have been published in relation to complications, sometimes fatal, associated to endoscopic ventriculocisternostomy (EVC). The objective of this study was to determine the range of complications using this surgical technique in a series of 108 patients.

METHODS

A retrospective and descriptive study was performed on 108 hydrocephalic patients: 76 children and 32 adults. All of them presented various forms of obstructive hydrocephalus.

RESULTS

In a total of 108 patients, 114 EVC were performed. The follow-up period ranged between 6 months and 10 years (mean 6.8 years). Age of patients ranged from 6 days to 75 years old (mean 18 years). Aqueductal stenosis was the most common aetiology, with 62 patients (57.4%). Significant complications occurred in 10 patients (9.2%). During the course of the study, the complication rate dropped significantly. No patient died because of the procedure (mortality 0%). We applied the Endoscopic Third Ventriculostomy Success Score (ETVSS) developed by Kulkarni and collaborators to our series to know if this score could be useful in predicting ETV results.

CONCLUSION

Like all minimally-invasive techniques, there is a steep learning curve for EVC. Correct patient selection and surgeon experience (which means not only familiarity with endoscopic techniques but also the performance of a minimum number of surgeries per year) are very important to avoid complications. The ETV Success Score devised closely approximates the predicted probability of ETV success.

[Treatment of child hydrocephalus by endoscopic third ventriculostomy in Senegal]

INTRODUCTION

Since its advent, endoscopic third ventriculostomy (ETV) has been an effective alternative to shunt placement for the treatment of hydrocephalus. The aim of this study was to report the results of our experience with this technique in children in Senegal.

MATERIALS AND METHODS

This was a retrospective study of 70 cases of children aged between 5 months to 15 years who were treated by ETV in the Neurosurgery Department of Fann Hospital in Dakar, between January 2010 to December 2012. The results were evaluated based on the clinical criteria of Drake and the Canadian Pediatric Neurosurgery Study Group. The mean follow-up duration was 24 months (9-32 months).

RESULTS

The mean age at diagnosis was 29 months. A male predominance (sex-ratio 1/3) was observed. We also noted a macrocephaly in 64.4 % of cases, psychomotor retardation in 40 % and decreased vision in 31.4 %. Headache and vomiting were found in 42.8 % and 61.4 % respectively. The main etiology was a stenosis of the mesencephalon aqueduct (30 %), followed by a Dandy-Walker malformation (25.7 %). Significant intraoperative bleeding was found in 2.8 % of patients. The most common postoperative complication was CSF leakage (18.6 %), followed by infections (14.2 %). The success rate according to the clinical criteria of Drake was 71.4 %. This success rate was influenced by the age of patients and the hydrocephalus etiology. No deaths occurred.

CONCLUSION

The endoscopic third ventriculostomy is a simple, safe and effective technique. Its advantages in terms of quality of life and morbidity compared with bypass valves makes it the technique of choice, particularly in developing countries.

Adjustment of the endoscopic third ventriculostomy entry point based on the anatomical relationship between coronal and sagittal sutures

Object

The coronal suture is often used as an empirical landmark for the entry point for endoscopic third ventriculostomy. The trajectory for the approach is often drawn based on midsagittal MRI findings. However, because the coronal suture is not perpendicular to the midline, this method may be inaccurate.

Methods

The junction of the coronal and sagittal sutures was exposed at the outer table of the cranium of 15 cadavers. An ideal coronal line was established perpendicular to the sagittal suture at the junction of the sagittal and coronal sutures. The distance from this ideal coronal line at the level of the coronal-sagittal junction to the actual coronal suture was measured at 1-cm intervals. The measured distance between the 2 planes was termed the distance to the coronal suture.

Results

The coronal suture bows forward as it moves from medial to lateral. From 1–6 cm lateral to the sagittal suture, the distance to the coronal suture was 0.1, 0.3, 0.5, 0.8, 1.0, and 1.4 cm, respectively. There was no significant difference between the right and left sides.

Conclusions

The position of a bur hole for endoscopic third ventriculostomy should be moved posteriorly with respect to the coronal suture the more laterally it is placed. Although the adjustment is small, it may be crucial. Failure to make this adjustment may result in suboptimal bur hole placement and increase the risk of morbidity.

Hydrocephalus in mucopolysaccharidosis type VI successfully treated with endoscopic third ventriculostomy

Mucopolysaccharidosis (MPS) Type VI, or Maroteaux-Lamy syndrome, is characterized by a deficiency of the enzyme arylsulfatase B (ASB). In patients with this disorder, craniocervical compression, carpal tunnel syndrome, and communicating hydrocephalus are common. Traditionally, hydrocephalus occurring in patients with MPS VI has been treated with shunt placements. Considering obstruction of the outlets from the fourth ventricle at the craniocervical transition, the authors decided to treat a female patient with MPS VI via endoscopic third ventriculostomy. She was 12 years old and had refractory headaches. This seems to be the first reported instance of the neuroendoscopic treatment of hydrocephalus in a patient with MPS VI. The pathophysiology is briefly discussed.

Needs assessment for simulation training in neuroendoscopy: a Canadian national survey

Object

In recent years, dramatic changes in surgical education have increased interest in simulation-based training for complex surgical skills. This is particularly true for endoscopic third ventriculostomy (ETV), given the potential for serious intraoperative errors arising from surgical inexperience. However, prior to simulator development, a thorough assessment of training needs is essential to ensure development of educationally relevant platforms. The purpose of this study was to conduct a national needs assessment addressing specific goals of instruction, to guide development of simulation platforms, training curricula, and assessment metrics for ETV.

Methods

Canadian neurosurgeons performing ETV were invited to participate in a structured online questionnaire regarding the procedural steps for ETV, the frequency and significance of intraoperative errors committed while learning the technique, and simulation training modules of greatest potential educational benefit. Descriptive data analysis was completed for both quantitative and qualitative responses.

Results

Thirty-two (55.2%) of 58 surgeons completed the survey. All believed that virtual reality simulation training for ETV would be a valuable addition to clinical training. Selection of ventriculostomy site, navigation within the ventricles, and performance of the ventriculostomy ranked as the most important steps to simulate. Technically inadequate ventriculostomy and inappropriate fenestration site selection were ranked as the most frequent/significant errors. A standard ETV module was thought to be most beneficial for resident training.

Conclusions

To inform the development of a simulation-based training program for ETV, the authors have conducted a national needs assessment. The results provide valuable insight to inform key design elements necessary to construct an educationally relevant device and educational program.

Endoscopic third ventriculostomy

Endoscopic third ventriculostomy (ETV) is considered as a treatment of choice for obstructive hydrocephalus. It is indicated in hydrocephalus secondary to congenital aqueductal stenosis, posterior third ventricle tumor, cerebellar infarct, Dandy-Walker malformation, vein of Galen aneurism, syringomyelia with or without Chiari malformation type I, intraventricular hematoma, post infective, normal pressure hydrocephalus, myelomeningocele, multiloculated hydrocephalus, encephalocele, posterior fossa tumor and craniosynostosis. It is also indicated in block shunt or slit ventricle syndrome. Proper Pre-operative imaging for detailed assessment of the posterior communicating arteries distance from mid line, presence or absence of Liliequist membrane or other membranes, located in the prepontine cistern is useful. Measurement of lumbar elastance and resistance can predict patency of cranial subarachnoid space and complex hydrocephalus, which decides an ultimate outcome. Water jet dissection is an effective technique of ETV in thick floor. Ultrasonic contact probe can be useful in selected patients. Intra-operative ventriculo-stomography could help in confirming the adequacy of endoscopic procedure, thereby facilitating the need for shunt. Intraoperative observations of the patent aqueduct and prepontine cistern scarring are predictors of the risk of ETV failure. Such patients may be considered for shunt surgery. Magnetic resonance ventriculography and cine phase contrast magnetic resonance imaging are effective in assessing subarachnoid space and stoma patency after ETV. Proper case selection, post-operative care including monitoring of ICP and need for external ventricular drain, repeated lumbar puncture and CSF drainage, Ommaya reservoir in selected patients could help to increase success rate and reduce complications. Most of the complications develop in an early post-operative, but fatal complications can develop late which indicate an importance of long term follow up.

Endoscopic Third Ventriculostomy Success Score (ETVSS) predicting success in a series of 50 pediatric patients. Are the outcomes of our patients predictable?

PURPOSE

In our series of endoscopic third ventriculostomy (ETV), we sought to establish the relationship between the preoperative prediction using the Endoscopic Third Ventriculostomy Success Score (ETVSS) and the postsurgical success rate.

MATERIALS AND METHODS

This descriptive analytical study comprised 50 pediatric patients who underwent 58 ETV procedures between 2003 and 2011. Data regarding clinical, surgical, and radiological findings were obtained from a continuously updated database. For each patient, we calculated the ETVSS, based on the patient's age, hydrocephalus etiology, and presence of a previous shunt. We considered success to be an established or improved clinical state and at least one of the following radiological criteria: (a) reduction in ventricular size or stable ventricles with disappearance of periventricular edema and increased subarachnoid space over cerebral convexities, (b) flow artifact in sagittal T2FSE MR, or (c) bidirectional flow signal in 2D-CPC MR. Statistical significance was set at p < 0.05. Six months was the minimum postoperative follow-up required.

RESULTS

The ETV was successful in 29 patients (58 %). Patients aged over 1 year achieved the best results (p < 0.019). For those who underwent successful ETV, the mean ETVSS was 71.03 (95 % CI, 66.23-75.84). In those for whom the ETV was not successful, the mean ETVSS was 60 (95 % CI, 53.09-66.90); (p < 0.007).

CONCLUSIONS

The success of ETV in our series could have been predicted by ETVSS. Predictability could help establish stricter surgical selection criteria, thereby obtaining higher success rates, as well as preparing the patients and their families for expected outcomes.

Changes in intracranial CSF distribution after ETV

OBJECTIVE

The aim of this prospective study was to analyze the changes in cerebrospinal fluid (CSF) distribution after endoscopic third ventriculocisternostomy (ETV).

METHODS

Twenty-two hydrocephalic children (eight boys, aged 3 months to 17 years) candidates for ETV were studied by preoperative brain magnetic resonance (MR) and repeated post-ETV MRs at established time intervals. A volumetric analysis of CSF distribution after ETV was performed using a specific software.

RESULTS

Fifteen children had an uneventful follow-up, whereas four required a second ETV due to a secondary closure of the stoma, one died of acute intracranial hypertension, and two needed an extrathecal shunt. A progressive reduction in the volume of the ventricles was found in case of successful ETV during the follow-up period. The ventricular volumes were reduced in average of 76 % of the initial volume at day 3, 69 % at 2 weeks, 42 % at 2 months, and 40 % at 6 months. This finding was associated with an enlargement of subarachnoid spaces which increased in case of successful ETV (192 % of initial volume at day 3; 210 % at day 15; 428 % at 2 months; and 468 % at 6 months). In case of secondary closure of the stoma, the distribution of intra- and extraventricular CSF tended to go back to the preoperative status.

CONCLUSION

Volume variations of the ventricles and the subarachnoid spaces are a good indicator of the efficacy of the ETV.

Ventriculoperitoneal shunt surgery outcome in adult transition patients with pediatric-onset hydrocephalus

BACKGROUND

Ventriculoperitoneal shunting remains the most widely used neurosurgical procedure for the management of hydrocephalus, albeit with many complications.

OBJECTIVE

To review and assess the long-term clinical outcome of ventriculoperitoneal shunt surgery in adult transition patients with pediatric-onset hydrocephalus.

METHODS

Patients 17 years or older who underwent ventriculoperitoneal shunt placement for hydrocephalus during their pediatric years (younger than 17 years) were included. Medical charts, operative reports, imaging studies, and clinical follow- up evaluations were reviewed and analyzed retrospectively.

RESULTS

A total of 105 adult patients with pediatric-onset hydrocephalus were included. The median age of the patients was 25.9 years. The median age at the time of the initial ventriculoperitoneal shunt placement was 1.0 year. The median follow-up time for all patients was 17.7 years. The incidence of shunt failure at 6 months was 15.2%, and the overall incidence of shunt failure was 82.9%. Single shunt revision occurred in 26.7% of the patients, and 56.2% had multiple shunt revisions. The cause of hydrocephalus was significantly associated with shunt survival for patients who had shunt failure before the age of 17 years. Being pediatric at first shunt revision, infection, proximal shunt complication, and other causes were independently associated with multiple shunt failures.

CONCLUSION

The findings of this retrospective study show that the long-term ventriculoperitoneal shunt survival remains low in adult transition patients with pediatric-onset hydrocephalus.

Neuronavigational neuroendoscopy--to be or not to be? An international pilot questionnaire-based study

OBJECTIVE

The almost age-old neuroendoscopy (NE) and neuronavigation (NN) in its twenties independently and indisputably have proved their high value as neurosurgical armamentarium and became even indispensable in some pathologies. However, nowadays the effectiveness of their simultaneous and combined application still is a matter of debate. The purpose of our pilot international, questionnaire-based survey was to assess the position of the opinion leaders in the field of neuroendoscopy worldwide toward the neuronavigational neuroendoscopy (NNNE).

METHODS

Within 3 months, a questionnaire with 17 questions was emailed repeatedly to 55 leading academic neuroendoscopic neurosurgeons from 50 institutions in 24 countries. The questionnaire covered aspects of personal and institutional experience in NE, NN, and NNNE, the most frequently treated pathologies by NNNE as well as inquiring the neurosurgeons' opinion for the importance and future of NNNE.

RESULTS

Forty-one questionnaires were returned (response rate = 74.6%). Six questionnaires were excluded because of incomplete or incorrect answers, leaving in the survey 35 respondents from 35 institutions in 18 countries. The less experienced neurosurgeons rely in higher degree on NNNE. Most frequently, NNNE is performed for hydrocephalus (procedures other than third ventriculostomy), transsphenoidal surgery, tumor biopsy, and cyst fenestration. Regardless their neurosurgical and NE experience, more than 75% of the respondents state that NNNE extends the range of neuroendoscopic procedures in their neurosurgical departments.

CONCLUSION

NNNE represents a valuable operative technique with excellent future prospects. NNNE extends the range of neuroendoscopic procedures, transforming some number of patients from "nonoperable" neuroendoscopically to suitable for neuroendoscopy.

Role of endoscopic third ventriculostomy at infected cerebrospinal fluid shunt removal

OBJECT

Cerebrospinal fluid shunt infection is distressing, especially in the pediatric population. Usually, infected CSF shunts are removed, and after temporary external CSF drainage, reinsertion of the CSF shunt is necessary. Unfortunately, it is not rare to encounter CSF reinfection after shunt renewal, and furthermore, the reinserted CSF shunt is at a considerable risk of malfunction. Endoscopic third ventriculostomy (ETV) is a potent option in managing CSF shunt infection, although ETV failure may occur more frequently when it is used to remove an infected shunt. The authors retrospectively evaluated CSF reinfection after using ETV during removal of infected CSF shunts; then the longevity of ETV and of successive reinserted ventriculoperitoneal shunts (VPSs) after ETV failure were also examined.

METHODS

Children with shunted hydrocephalus were retrospectively reviewed, and data on their initial CSF shunt infections were extracted. Thirty-six children underwent VPS reinsertion (the VPS group), and 9 underwent ETV after removal of the infected CSF shunt (the ETV group). As the primary outcome, ETV efficacy against CSF reinfection within 6 months was analyzed by comparing the reinfection rates, and the risk factors for CSF reinfection were analyzed by logistic regression. The longevity of the reinserted shunt in the VPS group was calculated using the Kaplan-Meier method, which was compared with ETV longevity as the secondary outcome, and also with the longevity of reinserted VPSs in the ETV group after ETV failure as the tertiary outcome.

RESULTS

Reinfection of CSF was seen in 27.8% of children in the VPS group. Among 9 children in the ETV group, only 1 (11.1%) had CSF reinfection. However, logistic regression analysis failed to show that performing ETV was a significant factor protecting against CSF reinfection: the significant risk factors were younger age at reinsertion of VPS or ETV (p = 0.037) and a history of shunt revisions (p = 0.011). The longevity of reinserted VPSs in the VPS group was calculated to be 658 ± 166.3 days (mean ± SE). Longevity of ETV was compared in the analysis of the secondary outcome, which was 929.2 ± 511.1 days, and there were no significant differences between these durations. Only 2 ETVs stayed patent, and a VPS was eventually implanted in the other 7 children. The longevity of this reinserted VPS in the ETV group, calculated based on these 7 children, was 2011.1 ± 540.7 days, which was confirmed to be longer than that in the VPS group (p = 0.031).

CONCLUSIONS

Although the protective effect of using ETV during removal of an infected CSF shunt on reinfection is marginal, the ETV longevity can be considered equivalent to that of reinserted VPSs. Even if ETV failure occurs, the reinserted VPS has significantly better longevity than a VPS reinserted without using ETV, and use of ETV during infected CSF shunt removal can be considered a potent alternative or at least an adjunct to VPS reinsertion.

The incorporation of neuroendoscopy in neurosurgical training programs

Previously considered the domain of the otolaryngologists, the endoscopy is now a common part of the armamentarium of a neurosurgeon. Neuroendoscopy or endoscope-assisted microsurgery is now being used in almost all routine procedures performed in the neurosurgical operating room. Hands-on training has become essential to learn the basics of neuroendoscopy, even for neurosurgeons well accustomed to the use of microscopes. To decrease the slope of the learning curve of residents during their training and reduce complications of procedures, most neurosurgery training programs around the world have incorporated laboratory or dissection programs in their curricula. Preconference workshops held during annual meetings are also an excellent tool to aid in the transition of surgeons from being a resident under the umbrella of an attending neurosurgeon to being a neurosurgeon able to operate independently and with confidence. In this "tech-savvy era," various cadaver or synthetic models are readily available for endoscopy training in a virtually simulated environment. In accord with the results of a surveys conducted by individual groups and societies, the authors firmly believe that incorporation of endoscopy in the neurosurgical curriculum would add a new dimension to the existing protocol. There is an urgent need for dedicated endoscopy training programs similar to postresidency fellowships in addition to translational research and establishment of dedicated societies to formulate guidelines for such research and monitor its progress.

Endoscopic third ventriculostomy and posterior fossa tumors

BACKGROUND

The management of hydrocephalus associated with a posterior fossa tumor is debated. Some authors emphasize the advantages of an immediate tumor removal that may normalize the cerebrospinal fluid (CSF) dynamics. However, in clinical practice, the mere excision of the lesion has been demonstrated to be accompanied by a persisting hydrocephalus in about one third of the cases. Preoperative endoscopic third ventriculostomy (ETV) offers several advantages. It may control the intracranial pressure (ICP), avoid the necessity of an emergency procedure, allow appropriate scheduling of the operation for tumor removal, and eliminate the risks related to the presence of an external drainage. The procedure also reduces the incidence of postoperative hydrocephalus. A final advantage, more difficult to weight, but obvious to the neurosurgeon, is the possibility to remove the lesion with a relaxed brain and normal ICP. In the postoperative phase, ETV can be used in case of persisting hydrocephalus, both in patients who underwent only the excision of the tumor and in those whose preoperative ETV failed as a consequence of intraventricular bleeding with secondary closure of the stoma (redoETV). The main advantage of postoperative ETV is that the procedure is carried out only in case of persisting hydrocephalus; its use is consequently more selective than preoperative ETV. The disadvantage consists in the common use of an external CSF drainage in the first few postoperative days, which is necessary to control the pressure and for ruling out those cases that reach a spontaneous cure of the hydrocephalus.

METHODS

The authors review the criteria for patient selection and the results of ETV performed in case of hydrocephalus secondary to a posterior fossa tumor.

RESULTS AND CONCLUSIONS

Preoperative ETV constitutes an effective procedure for controlling the hydrocephalus associated with posterior fossa tumors. It might lower the rate of persistent postoperative hydrocephalus and result in a short hospital stay. Low rates of patients requiring an extrathecal-CSF shunt device are also reported by authors who utilize ETV postoperatively. As, however, the assessment of the persistent hydrocephalus in these children is based on prolonged ICP monitoring through an external CSF drainage, their results are weighted by a major risk of infective complications and longer hospital stay.

Efficacy and versatility of the 2-micron continuous wave laser in neuroendoscopic procedures

Laser-assisted techniques offer a huge potential in neurosurgery, but have achieved little acceptance to date. One reason is the concern regarding heat production, uncontrollable and distant penetration, and tissue interaction.We describe our experience with a 2-micron continuous wave laser (RevoLix jr.; LISA Laser Products OHG, Katlenburg-Lindau, Germany) for neuroendoscopic intraventricular procedures.The laser beam is delivered through flexible fibers. In an aqueous medium, the effect is restricted to <2 mm in front of the tip with tissue penetration depth of 500 μm.Forty-four patients (25 adults, 19 children) were operated on using the endoscopic, laser-assisted technique for treatment of obstructive hydrocephalus (n = 39), pure cyst fenestration (n = 4), or pure tumor biopsy (n = 1). All 53 procedures were successfully performed in those 44 operations, with the laser being the main effective instrument used (except for biopsy). Besides one clinically silent small intracisternal hemorrhage and one worsening of a preexisting oculomotor palsy (following fenestration of multiple midbrain cysts), no procedure-related complications occurred.The 2-micron continuous wave laser is a most valuable and useful tool, in our experience with safe applicability for endoscopic intracranial procedures in patients of all ages.

Complications of endoscopic third ventriculostomy: a systematic review

INTRODUCTION

Endoscopic third ventriculostomy (ETV) is an established treatment for hydrocephalus. Most studies focus on success rates, and complications are insufficiently charted. The aim of this study was to perform a systematic review of ETV complications.

METHODS

A Medline search discovered 24 series of ETV (seven in children, five in adults, and 12 in a mixed-age group) with detailed complications reports.

RESULTS

The analysis included 2,672 ETVs performed on 2,617 patients. The cause of hydrocephalus was aqueductal stenosis in 25.9%, tumor 37.0%, meningomyelocele-Chiari II 6.1%, posthemorrhagic 5.8%, postinfectious 1.4%, cysts 3.3%, Chiari I 0.4%, Dandy-Walker malformation 0.3%, cerebellar infarct 0.9%, normal pressure hydrocephalus 1.3%, and not recorded 16.8%. Overall complication rate was 8.8%. Permanent morbidity was 2.1%, neurologic in 1.2% (hemiparesis, gaze palsy, memory disorders, and/or altered consciousness), hypothalamic in 0.9% (diabetes insipidus, weight gain, or precocious puberty). Intraoperative hemorrhage was present in 3.9%, severe in 0.6% (including four cases [0.14%] of basilar rupture). Other surgical complications were 1.13% (three thalamic infarcts, six subdural, six intracerebral, and two epidural hematomas). Cerebrospinal fluid (CSF) infections occurred in 1.8%, CSF leak in 1.7%, anesthetic complications (bradycardia and hypotension) in 0.19% of cases. Postoperative mortality was 0.22% (six patients; sepsis two, hemorrhage three, and thalamic injury one). Another two children suffered delayed "sudden death" (after 25 and 60 months), caused by acute hydrocephalus due to stoma occlusion. There were no differences between pediatric and adult patients or short and long series (cutoff 100 patients). All deaths were reported in long series. Complication rates were insignificantly higher in short series.

CONCLUSIONS

Permanent morbidity after ETV is 2.1%, mortality is 0.22%. The incidence of delayed "sudden death" is 0.07%.

Evaluating the Children's Hospital of Alabama endoscopic third ventriculostomy experience using the Endoscopic Third Ventriculostomy Success Score: an external validation study

OBJECT

Endoscopic third ventriculostomy (ETV) success is dependent on patient characteristics including age, origin of hydrocephalus, and history of shunt therapy. Using these factors, an Endoscopic Third Ventriculostomy Success Score (ETVSS) model was constructed to predict success of therapy. This study reports a single-institution experience with ETV and explores the ETVSS model validity.

METHODS

A retrospective chart review identified 151 consecutive patients who underwent ETV at a pediatric hospital between August 1995 and December 2009. Of these 151, 136 patients had at least 6 months of clinical follow-up. Data concerning patient characteristics, operative characteristics, radiological findings, complications, and success of ETV were collected. The actual success rates were compared with those predicted by the ETVSS model.

RESULTS

The actual success rate of ETV at 6 months was 68.4% (93 of 136 patients), which compared well to the predicted ETVSS of 76.5% ± 12.5% (± SD). The C-statistic was 0.74 (95% CI 0.65-0.83), suggesting that the ability of the ETVSS to discriminate failures from successes was good. Secondary ETV was found to have a hazard ratio for failure of 4.2 (95% CI 2.4-7.2) compared with primary ETV (p < 0.001). The complication rate was 9.3% with no deaths. At the first radiological follow-up, the increased size of ventricles had a hazard ratio for failure of 3.0 (95% CI 1.5-6.0) compared with patients in whom ventricle size either remained stable or decreased (p = 0.002).

CONCLUSIONS

The ETVSS closely predicts the actual success of ETV, fitting the statistical model well. Shortcomings of the model were identified in overestimating success in patients with ETVSS ≤ 70, which may be attributable to the poor success of secondary ETVs in the authors' patient population.

Single burr hole endoscopic biopsy with third ventriculostomy-measurements and computer-assisted planning

OBJECTIVE

In cases of non-communicating hydrocephalus, a combined endoscopic third ventriculostomy (ETV) and tumor biopsy might be necessary. We suggest a computer-assisted planning procedure to perform ETV and biopsy via a single burr hole.

METHODS

In 15 patients with non-communicating hydrocephalus with a mass obstructing the Sylvian aqueduct, an ETV in parallel to targeting the lesion was planned to be performed via a single burr hole. Prior to surgery, a 3D MRI data set was planned to be acquired for computer-assisted planning. The lesion target points were located in the third ventricle or in the lateral ventricle. By defining the optimal entry point as single burr hole, the trajectory was calculated to cause the least amount of tissue shift at the foramen of Monro (FM) or within the hemispheric tissue. The burr hole localization was measured relative to nasion and to midline. The diagnostic yield and the success rate of ETV were evaluated.

RESULTS

The optimal entry point for third ventricular lesions was 111 ± 17 mm to the nasion and 16 ± 11 mm to the midline. Tissue shift at the level of FM was 2.4 ± 4 mm. For targeting the floor of the third ventricle in parallel to lesions of the lateral ventricle, the entry point was at 122 ± 11 mm to the nasion and 17 ± 9 mm to the midline. Rate of diagnostic yield was 86.7%. Success rate of ETV at follow-up of 34 ± 19 months was 86.7%.

CONCLUSIONS

Performing ETV in parallel to target paraventricular lesions causing a hydrocephalus is feasible via a single burr hole by using computer-assisted planning and performing a navigated endoscopic procedure.

The oculomotor nerve: anatomic relationship with the floor of the third ventricle

PURPOSE

Endoscopic third ventriculostomy (ETV) has become first-line treatment for obstructive hydrocephalus. Many complications have been described, but the literature about oculomotor palsy after ETV is scarce. Therefore we undertook an anatomical study of the relationship of the oculomotor nerve to the floor of the third ventricle.

METHODS

Distances and angles between the third nerve and the bottom of the third ventricle were studied both in two cadaver heads and in high-definition CISS images in 16 MRI scans. The angles of the trajectories putting the nerve at risk or not were compared. Finally, in a retrospective analysis of intraoperative images the appearance of the membranous portion of the floor was defined and if visible, the distance of the third nerve to the midline was estimated by comparing with the 8-mm balloon catheter.

RESULTS

The course of the third nerve is approximately 8 mm laterally and approximately 17 mm caudally distant from the midpoint of the floor of the third ventricle. The angle of the trajectory to damage the third nerve is at least 12° greater than any safe angle of ETV trajectory through a normal burr hole.

CONCLUSIONS

The third nerve is not always visible during ETV procedures, but the angular and linear measurements imply that the risk to damage the nerve should be relatively small. Confirmation of these data in hydrocephalic patients with distorted anatomy is needed.

Complications of endoscopic third ventriculostomy

OBJECT

Endoscopic third ventriculostomy (ETV) is an established treatment for hydrocephalus. Most studies focus on success rate, and complications are insufficiently documented. The aim of this study was to perform a systematic review of ETV complications.

METHODS

A Medline search discovered 34 series of ETV with detailed complications reports (17 series involving exclusively pediatric patient populations, 6 series involving exclusively adults, and 11 series involving mixed adult and pediatric populations).

RESULTS

The analysis included 2985 ETVs performed in 2884 patients. The cause of hydrocephalus was aqueductal stenosis in 29.3% of patients, tumor in 37.6%, meningomyelocele in 7.6%, cysts in 2.6%, cerebellar infarct in 0.9%, Dandy-Walker malformation in 0.6%, and Chiari malformation Type I in 0.4%; 7.4% of the patients had posthemorrhagic hydrocephalus, 1.8% had postinfectious hydrocephalus, and 1.2% had normal pressure hydrocephalus. Hydrocephalus was due to other causes in 1.3% of cases and the cause was not reported in 9.8%. The overall complication rate was 8.5%. The rate of permanent morbidity was 2.38%; the rate of permanent neurological complications was 1.44% (hemiparesis, gaze palsy, memory disorders, altered consciousness), and the rate of permanent hormonal morbidity was 0.94% (diabetes insipidus, weight gain, precocious puberty). The rate of intraoperative hemorrhage rate was 3.7%; the rate of severe intraoperative hemorrhage was 0.6% (including a 0.21% rate of basilar rupture). The rate for intraoperative neural injury (thalamic, forniceal, hypothalamic, and midbrain injuries) was 0.24%. Central nervous system infections occurred in 1.81% of cases, CSF leak in 1.61%, and postoperative intracranial hematomas in 0.81% of cases. The early postoperative mortality rate was 0.21% (6 patients died; 2 of sepsis and 4 of hemorrhage). Another 2 children suffered delayed "sudden death" (one after 25 months and the other after 60 months), caused by acute hydrocephalus due to stoma occlusion. There were no significant differences between series involving pediatric or adult patient populations or series with fewer than 100 or more than 100 patients. All reported deaths were in series involving more than 100 patients.

CONCLUSIONS

Endoscopic third ventriculostomy can be regarded as a low-complication procedure, with an overall complication rate of 8.5%, permanent morbidity rate of 2.4%, mortality rate of 0.21%, and delayed "sudden death" rate of 0.07%.

A Review of Neuroendoscopy and Potential Applications in Veterinary Medicine

The endoscope was first developed over 200 yr ago. Endoscopy has since been applied to many disciplines of medicine. Its application to the nervous system was initially slow and not widely accepted and mainly involved the biopsy of tumors and the treatment of hydrocephalus. Several reasons for neuroendoscopy's limited use include inadequate endoscope technology, high skill level required, the advent of the surgical microscope, and the development of other treatments such as ventricular shunting. Over the past 50 yr, improvements in optical glass lenses, fiber optics, and electrical circuitry has led to better equipment and a revival of neuroendoscopy. Neuroendoscopy is now used in many diseases in human medicine including hydrocephalus, neoplasia, and intracranial cysts. This review presents the history of neuroendoscopy, the equipment and technology used, and the possible translation of techniques currently used in human medicine to veterinary medicine.

Minimally invasive neurosurgery for cerebrospinal fluid disorders

This article focuses on minimally invasive approaches used to address disorders of cerebrospinal fluid (CSF) circulation. The author covers the primary CSF disorders that are amenable to minimally invasive treatment, including aqueductal stenosis, fourth ventricular outlet obstruction (including Chiari malformation), isolated lateral ventricle, isolated fourth ventricle, multiloculated hydrocephalus, arachnoid cysts, and tumors that block CSF flow. General approaches to evaluating disorders of CSF circulation, including detailed imaging studies, are discussed. Approaches to minimally invasive management of such disorders are described in general, and for each specific entity. For each procedure, indications, surgical technique, and known outcomes are detailed. Specific complications as well as strategies for their avoidance and management are addressed. Lastly, future directions and the need for structured outcome studies are discussed.

Anaesthesia for endoscopic neurosurgical procedures

PURPOSE OF REVIEW

Endoscopic neurosurgical procedures are becoming more frequent and popular in the treatment of intracranial disease. When endoscopy involves the intraventricular structures, irrigating solutions are required and may contribute to sudden and sharp increases in intracranial pressure. More recently, nasal endoscopic approach has been used to perform skull base surgery for aneurysms and tumours. We have analysed published articles in order to detect anaesthesia management and perioperative complications.

RECENT FINDINGS

Sudden and dangerously low decreases in cerebral perfusion pressures do not provoke the 'traditional Cushing's response' usually associated with significantly high intracranial pressure. It is important to note that tachycardia (not bradycardia) and/or hypertension are the most frequent haemodynamic complications during neuroendoscopic procedures. With the transnasal approach severe intraoperative haemorrhage is the most important complication to consider followed by direct injury to surrounding neural structures.

SUMMARY

Invasive arterial blood pressure and intracranial pressure should be measured continuously during neuroendoscopies to detect early intraoperative cerebral ischaemia instead of waiting for the appearance of bradycardia which may be a late sign. General anaesthesia remains the technique of choice. Intracranial haemorrhage increases the likelihood of perioperative complications. Close postoperative monitoring is required to diagnose and treat complications such as convulsions, persistent hydrocephalus, haemorrhage or electrolytic imbalance.

Feasibility of ventricular expansion postmortem: a novel laboratory model for neurosurgical training that simulates intraventricular endoscopic surgery

OBJECT

Cadavers are often used in the teaching of various neurosurgical procedures. One aspect of this resource that has not been previously explored is the postmortem dilation of the ventricular system, which is often collapsed, for the purpose of training neurosurgeons in the use of intraventricular endoscopy.

METHODS

Nine adult cadavers without a history of hydrocephalus or other known intracranial pathology were used for this study. Four specimens were obtained post embalming, and 5 specimens were fresh (time from death until the procedure < 5 hours). In all cadavers catheters were placed into the lateral ventricles; saline and then air were injected into the ventricles through the catheters. Ventriculostomy sites were filled with rubber stoppers, and in fresh specimens, formal embalming was performed with cadavers in the Trendelenburg position. Lastly, serial horizontal sectioning of the cranium was performed in all cadavers to verify ventricular dilation.

RESULTS

None of the 4 embalmed specimens were found to have ventriculomegaly following injection. However, this condition was found in 4 of the 5 fresh specimens. In the single fresh cadaver without ventriculomegaly, the cause of death had been massive intracranial subarachnoid hemorrhage, which distorted the ventricular system. This may have prevented cannulation of the ventricle and ventricular expansion in this specimen.

CONCLUSIONS

The ventricular system of fresh human cadavers can be dilated postmortem. The method described herein may be useful to neurosurgical trainees or those trained neurosurgeons wishing to practice intraventricular endoscopy.

[Early epidural hematoma after CSF shunt for obstructive hydrocephalus]

We present the first case of early epidural hematoma after CSF shunt probably caused by defective material. A 26-year-old man was treated for obstructive hydrocephalus associated with a tonsillar herniation, revealed by headaches and papillary edema. Ventriculoperitoneal shunt was preferred to endoscopic ventriculostomy. Three hours after the operation, the patient fell into a coma, developing a voluminous bifrontal epidural hematoma that was evacuated immediately. The patient completely recovered neurologically. One month later, to treat persistent hydrocephalus, endoscopic ventriculostomy was performed without incident. Then the shunt was removed and an opening threshold close to zero was discovered. Distant MRI showed a reduction in ventricular size, normalization of the tonsils' position and a tumor of the tectal plate. To our knowledge, this is the only case of early epidural hematoma after ventriculoperitoneal shunt. We discuss the choice of treatments for obstructive hydrocephalus and its risks and complications.