Augmented reality in intraventricular neuroendoscopy

BACKGROUND

Individual planning of the entry point and the use of navigation has become more relevant in intraventricular neuroendoscopy. Navigated neuroendoscopic solutions are continuously improving.

OBJECTIVE

We describe experimentally measured accuracy and our first experience with augmented reality-enhanced navigated neuroendoscopy for intraventricular pathologies.

PATIENTS AND METHODS

Augmented reality-enhanced navigated endoscopy was tested for accuracy in an experimental setting. Therefore, a 3D-printed head model with a right parietal lesion was scanned with a thin-sliced computer tomography. Segmentation of the tumor lesion was performed using Scopis NovaPlan navigation software. An optical reference matrix is used to register the neuroendoscope's geometry and its field of view. The pre-planned ROI and trajectory are superimposed in the endoscopic image. The accuracy of the superimposed contour fitting on endoscopically visualized lesion was acquired by measuring the deviation of both midpoints to one another. The technique was subsequently used in 29 cases with CSF circulation pathologies. Navigation planning included defining the entry points, regions of interests and trajectories, superimposed as augmented reality on the endoscopic video screen during intervention. Patients were evaluated for postoperative imaging, reoperations, and possible complications.

RESULTS

The experimental setup revealed a deviation of the ROI's midpoint from the real target by 1.2 ± 0.4 mm. The clinical study included 18 cyst fenestrations, ten biopsies, seven endoscopic third ventriculostomies, six stent placements, and two shunt implantations, being eventually combined in some patients. In cases of cyst fenestrations postoperatively, the cyst volume was significantly reduced in all patients by mean of 47%. In biopsies, the diagnostic yield was 100%. Reoperations during a follow-up period of 11.4 ± 10.2 months were necessary in two cases. Complications included one postoperative hygroma and one insufficient fenestration.

CONCLUSIONS

Augmented reality-navigated neuroendoscopy is accurate and feasible to use in clinical application. By integrating relevant planning information directly into the endoscope's field of view, safety and efficacy for intraventricular neuroendoscopic surgery may be improved.

Developing a new transparent sheath for endoscopic third ventriculostomy in treating hydrocephalus patients

BACKGROUND

The sheath is a crucial piece of equipment during endoscopic third ventriculostomy (ETV). However, the normally used metal sheath can not provide clear images around the tube.

OBJECTIVE

We developed a new transparent sheath (TS) in order to overcome the inherent disadvantages of the metal sheath (MS).

MATERIAL AND METHODS

Between August 2010 and February 2013, a total of 120 hydrocephalus patients received ETV in our hospital. Patients were retrospectively divided into two groups, the transparent sheath group (TSG) and metal sheath group (MSG). The success rate of the first puncture, the operative time and the incidence of complications were used to compare the efficiency between transparent sheath and metal sheath.

RESULTS

There were 32 patients in the TSG and 88 patients in the MSG. The success rate of the first puncture was 100% in the TSG and 87.5% in the MSG, respectively (p= 0.036). The operative time of the TSG was significant shorter than the MSG (p= 0.001). While the incidence of complications was similar between the two groups (p= 0.757).

CONCLUSIONS

Compared with the tranditional metal sheath, the newly developed transparent sheath for ETV is more efficient and showed lower risk. This may be explained by the better surgical view of the whole puncture channel provide by the TS.

Guided (VENTRI-GUIDE) versus freehand ventriculostomy: study protocol for a randomized controlled trial

BACKGROUND

Despite the widespread use of external ventricular drainage, revision rates, and associated complications are reported between 10 and 40%. Current available image-guided techniques using stereotaxy, endoscopy, or ultrasound for catheter placements remain time-consuming techniques. Recently, a smartphone-assisted guide with high precision has been described. The development of an easy-to-use, portable, image-guided system could reduce the need for multiple passes and improve the rate of accurate catheter placement. This study aims to prospectively compare in a randomized controlled manner the accuracy of the freehand pass technique versus an easy-to-use, portable, adjustable guiding device for ventriculostomy catheter placement.

METHODS/DESIGN

This is a single center, prospective, randomized trial with a blinded endpoint (ventricular catheter tip location) assessment. Adult patients with the indication for ventriculostomy, as proven by computed tomography (CT), will be randomly assigned to the treatment group or the control group. For patients in the treatment group, ventriculostomy will be performed using an adjustable guiding device and DICOM (Digital Imaging and Communications in Medicine) image-reading software assistance (for example, using a mini-tablet) based on preoperative CT imaging.Patients in the control group will receive standard freehand ventriculostomy using anatomical landmarks. The catheter may be placed for external drainage or internal (ventriculoperitoneal) shunting in both groups. The primary outcome measure is the rate of correct placements of the ventricular catheter, defined as a score of 1 to 3 on grading system for catheter tip location on a postoperative CT scan. Participants will be followed for the duration of hospital stay, an expected average of two weeks. The primary outcome will be determined by one of the authors blinded to the treatment allocation. We aim to include 236 patients in three years. Secondary outcome measures include: frequency of placements required, frequency of completed placements within the ventricle of the perforated part of the catheter tip, frequency of very early and early shunt failures (revision of the ventricular drainage within 24 hours and within the hospital stay), frequency and percentage of complications (procedure-related and nonsurgical) at discharge.

DISCUSSION

This is the study design of a single center, prospective, randomized controlled trial to investigate whether guided ventriculostomy is superior to the standard freehand technique. One strength of this study is the prospective, randomized, interventional type of study testing a new easy-to-handle guided versus freehand ventricular catheter placement. A second strength of this study is that the power calculation is based on catheter accuracy using an available grading system for catheter tip location, and is calculated with the use of recent study results of our own population, supported by data from prominent studies.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02048553 (registered on 28 January 2014).

Application of indocyanine green (ICG) fluorescence for endoscopic biopsy of intraventricular tumors

BACKGROUND

Many reports have already indicated the benefit of pathological diagnosis of intra- and periventricular tumors with neuroendoscopic biopsy. However, it is also well known that studies can be occasionally inconclusive because of the small and/or inadequate samples for identification of abnormal tissues. The application of indocyanine green (ICG) fluorescence for endoscopical tumor biopsy under the intraventricular surroundings is a new area not previously reported. We attempted visual differentiation of intraventricular lesions from the surrounding structure using ICG fluorescence and considered the most appropriate region for biopsy.

METHODS

Three cases (13–14 year-old boys) with secondary hydrocephalus caused by intra- and periventricular tumors were operated for endoscopic transventricular biopsy combined with endoscopic third ventriculostomy. Final pathological diagnoses were suprasellar malignant lymphoma and germ cell tumors in two patients, both associated with intraventricular dissemination. Enhanced tumor visualization with 12.5 mg of ICG administration was obtained using the D-light P light equipment and ICG telescope 5.8 mm/19 cm.

RESULTS

It was possible to identify the tumor mass margins themselves and detect the differences of intratumoral ICG accumulation. The areas of tumor dissemination were identifiable by neuroendoscopy but unable to be visualized by ICG fluorescence.

CONCLUSIONS

We were able to obtain an ICG fluorescence imaging inside the cerebral ventricles by new D-light P system comprised of a camera head telescope. ICG fluorescence with neuroendoscopy can provide useful information for choosing the point of biopsy of intra- and periventricular tumors. However, we need to assess if the ICG accumulation site is the most appropriate for biopsy.

Endoscopic treatment of in utero diagnosed multiloculated interhemispheric cyst in a newborn: case report

Interhemispheric cysts, often associated with agenesis of corpus callosum, are rare lesions. The optimal treatment is still controversial. Placement of cystoperitoneal shunt and open microsurgery are traditional treatments. Neuroendoscopy in children is due to its minimal invasiveness a new emerging option. There have been a few published cases on neuroendoscopic treatment of interhemispheric cyst in children. The authors document the youngest reported child with multiloculated interhemispheric cyst that was treated with neuroendoscopy. The cyst was detected in a male fetus in 35th week of gestation and in utero magnetic resonance imaging was performed in 37th week of gestation. After delivery, progressive macrocrania with signs of raised intracranial pressure developed. Endoscopic cystoventriculocisternostomy was performed 28 days after the birth. There was a marked symptom relief. One month after the surgery, magnetic resonance showed shrinkage of the cyst and expansion of the brain parenchyma. After a 2-month follow up period, the child showed normal neurologic development and head circumference increased by only 0.5 cm. The created fenestrations enabled the brain to expand. Neuroendoscopic treatment,of interhemispheric cysts should be considered the operative technique of choice in newborns. Although the intracranial pressure and the size of the cyst have decreased, long-term follow up is necessary and future studies on more cases are needed.

Efficacy of reductive ventricular osmotherapy in a swine model of traumatic brain injury

BACKGROUND

The presence of osmotic gradients in the development of cerebral edema and the effectiveness of osmotherapy are well recognized. A modification of ventriculostomy catheters described in this article provides a method of osmotherapy that is not currently available. The reductive ventricular osmotherapy (RVOT) catheter removes free water from ventricular cerebrospinal fluid (CSF) by incorporating hollow fibers that remove water vapor, thereby providing osmotherapy without increasing osmotic load.

OBJECTIVE

To increase osmolarity in the ventricular CSF through use of RVOT in vivo.

METHODS

Twelve Yorkshire swine with contusional injury were randomized to external ventricular drainage (EVD) or RVOT for 12 hours. MR imaging was obtained. Serum, CSF, and brain ultrafiltrate were analyzed. Histology was compared using Fluor-Jade B and hematoxylin and eosin (H & E) stains.

RESULTS

With RVOT, CSF osmolality increased from 292 ± 2.7 to 345 ± 8.0 mOsmol/kg (mean ± SE, P = 0.0006), and the apparent diffusion coefficient (ADC) in the injury region increased from 0.735 ± 0.047 to 1.135 ± .063 (P = 0.004) over 24 hours. With EVD controls, CSF osmolarity and ADC were not significantly changed. Histologically, all RVOT pigs showed no evidence of neuronal degeneration (Grade 1/4) compared to moderate degeneration (Grade 2.6 ± .4/4) seen in EVD treated animals (P = 0.02). The difference in intracranial pressure (ICP) by area under the curve approached significance at P = .065 by Mann Whitney test.

CONCLUSION

RVOT can increase CSF osmolarity in vivo after experimental traumatic brain injury (TBI). In anticipated clinical use, only a slight increase in CSF osmolarity may be required to reduce cerebral edema.

Effect of tunnel length on infection rate in patients with external ventricular drain

BACKGROUND

External ventricular drain involves catheter placement in ventricles of brain. It is used for various purposes. Basic theme is to drain cerebrospinal fluid so as to control intracranial pressure. This study was carried out to see the effect of tunnel length on rate of infection.

METHODS

This was a cross-sectional study carried out in Department of Neurosurgery, Pakistan Institute of Medical Sciences, Islamabad during 14 months from 1st December 2008 to 31 January 2010. External ventricular drain was placed in admitted patients after meticulous aseptic technique in operation theatre at right Kocher's point. It was carried out through a scalp tunnel and was connected to drainage bag through a drip set. Both long (> 5 Cm) and short (< 5 Cm) tunnels were randomly made. Infection rate was estimated in patients who had change of cerebrospinal fluid colour or developed fever (as per protocol to have minimum handling of drain). All patients received prophylactic Ceftriaxone.

RESULTS

Among 76 patients long tunnel was made in 44 (57.9%) and short in 32 (42.1%). Three patients (3.9%) with long tunnel while 6 (7.9%) patients with short tunnel had infection. The overall infection was in 9 (11.8%) patients.

CONCLUSION

External ventricular drain tunnel length strongly influences the rate of infection.

The application of ultrasound in neuroendoscopic procedures: first results with the new tool "NECUP-2"

In this paper, our experience with originally constructed Neurosurgical Endoscopic Contact Ultrasound Probe "NECUP-2" in neuroendoscopy is reported. Between June 1997 and June 2007, 132 neuroendoscopic procedures have been performed: 102 endoscopic thrid ventriculostomies (ETV), 15 arachnoid cysts and 5 intraventricular tumours operations. The "NECUP-2" was applied effectively in all cases in which blunt perforation was not possible: 38/102 ETY, 10/10 septostomies, 15/15 arachnoid cysts. In five cases of intraventricular tumours, neuroendoscopic procedure was combined with open microsurgery for tumour removal with preservation of vascular structures. There were no "NECUP-2" related complications. Of postoperative complications, we had liquorrhea (9 patients), and symptoms of meningitis (6 patients). In the follow-up period (6 months to 6 years), we had a patency rate of 80% (50/63 patients). All patients improved in clinical status. According to the first results, it seems that ultrasonic contact probe NECUP-2 presents a new device in neurosurgical armamentarium that can be used in various fields of neurosurgery. With minimal and controlled lesion that is produced at the tip of the probe, it can be used in highly demanding operations such as third ventriculostomy and tumour resection.

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.

A restricted neuroendoscopic approach for pathological diagnosis of intraventricular and paraventricular tumours

BACKGROUND

There is increasing interest in the use of neuroendoscopic techniques in neuro-oncology. We report our experience of endoscopic biopsy in patients harbouring intraventricular and paraventricular brain tumours in order to define criteria for the use of this technique.

METHODS

We identified 23 patients (aged 7-78 years) who underwent endoscopic biopsy for intraventricular or paraventricular lesions considered not suitable for surgical removal and too risky for a stereotactical approach. All of the biopsies were obtained with a flexible endoscope using a free-hand technique.

FINDINGS

In 16 patients specimens were adequate and led to a diagnosis; in three patients they were informative but not completely diagnostic; a pathological diagnosis was unavailable in four patients. In 13 patients with a lesion causing an obstruction of the aqueduct, a third ventriculostomy was performed during the same procedure; in one patient with a lesion occluding the Monro foramen, a septostomy was done, while in another case multiple cystostomies were required. No specific complications were observed, either clinically or radiologically, in particular no major bleeding occurred.

CONCLUSIONS

In our experience, endoscopic biopsy could provide a pathological diagnosis in 19 of 23 patients. Endoscopic biopsy sampling sufficient tissue should be considered as the first choice in selected lesions that are otherwise difficult to approach.

Complications of endoscopic third ventriculostomy

OBJECTS

Although endoscopic third ventriculostomy (ETV) is considered as the first choice in the management of noncommunicating hydrocephalus, it is not without risk or complication.

METHODS

The patients who had undergone ETV only between 1998 and 2005 were retrospectively reviewed. There were 85 males and 70 females, and 173 ETVs were performed in 155 patients. The patients' age ranged from 2 months to 77 years. Complications were categorized as (1) intraoperative, (2) early postoperative (<1 month), and (3) late postoperative (>1 month). Follow-up of the patients ranged from 1 to 86 months.

RESULTS

Overall complication rate per patient was 15.4%, and complication per procedure was 18%. Complication rate significantly varied with the etiology of hydrocephalus (P = 0.013). The patients with Chiari type I malformation and tumor had no or very low complication rates. The complication risk was significantly higher in repeat endoscopic procedure (55.5%) than in the first procedure (10%; P = 0.0001).

CONCLUSION

ETV should be the first choice in the management of noncommunicating hydrocephalus. Training, experience, and meticulous technique will decrease the complication rate. Patients undergoing ETV should be followed in a similar manner to patients with cerebrospinal fluid shunts.

Neuroendoscopic foraminal plasty of foramen of Monro

OBJECTIVES

The aims of this study were to describe and analyze the technique of neuroendoscopic foraminal plasty of foramen of Monro (NEFPFMO) in the treatment of isolated unilateral hydrocephalus (IUH) due to membranous occlusion, to evaluate its efficacy and safety, and to define the benefits of neuronavigational guidance of the procedure.

MATERIALS AND METHODS

Two symptomatic neonates with IUH, as a result of congenital atresia of foramen of Monro, underwent NEFPFMO plus neuroendoscopic septostomy in the first case and neuronavigational guidance in the second one. Clinical results were excellent in both neonates. The postoperative ventricular size decreased and the progressive IUH changed to the state of arrested hydrocephalus. The neuronavigation was precise.

CONCLUSION

NEFPFMO should be the primary treatment option in patients with IUH due to membranous occlusion of foramen of Monro. It reestablishes natural anatomical communication and provides real physiological cerebrospinal fluid flow. Neuronavigation is a useful adjunct of NEFPFMO.

The role of Ommaya reservoir and endoscopic third ventriculostomy in the management of post-hemorrhagic hydrocephalus of prematurity

OBJECTIVE

The aim of this study is to retrospectively evaluate a series of consecutive patients affected by post-hemorrhagic hydrocephalus in prematurity, treated with an implant of an Ommaya reservoir followed by ventriculo-peritoneal (VP) shunt and/or endoscopic third ventriculostomy (ETV) to evaluate the safety and efficacy of these treatment options in the management of the condition.

METHODS

Between 2002 and 2005, 18 consecutive premature patients affected by intra-ventricular haemorrhage (IVH) grades II to IV, presenting with progressive ventricular dilatation, were operated for implant of an intra-ventricular catheter connected to a sub-cutaneous Ommaya reservoir. Cerebrospinal fluid was intermittently aspirated percutaneously by the reservoir according with the clinical requirements and the echographic follow-up. The patients who presented a progression of the ventricular dilatation were finally operated for VP shunt implant or ETV according with the MRI findings.

RESULTS

One patient had grade II, 5 had grade III, and 12 had grade IV IVH. The mean age at IVH diagnosis was 5.2 days; the mean age at reservoir implant was 17.3 days. The Ommaya reservoir was punctured on an average basis of 11.4 times per patient (range 2-25), and the mean interval between aspirations was 2.7 days. The mean CSF volume per tap was 20 ml. One patient died for pulmonary complications during the study period. Out of the 17 survivors, 3 did not develop progressive ventricular dilatation, and their reservoir was removed; 14 developed progressive hydrocephalus, 5 of whom were implanted with a VP shunt and 9 received an ETV. Amongst the five shunted patients, two were re-admitted for shunt malfunction and had their shunt removed after ETV after 6.1 and 20.5 months, respectively. Amongst the nine patients who received an ETV, five had to be re-operated for VP shunt implant at an average interval of 2.17 months (range 9-172 days) because of increasing ventricular dilatation. Two of them had a redo third ventriculostomy with shunt removal at 11 and 25.1 months, respectively, after insertion. The first was reimplanted with a VP shunt 4 days later; the second remains shunt free. Therefore, at the end of the follow-up period, 10 out of 17 children affected by post-hemorrhagic hydrocephalus in prematurity were shunt free (59%).

CONCLUSIONS

The combination of Ommaya reservoir, VP shunt, and the aggressive use of ETV as a primary treatment or as an alternative to shunt revision allowed for a significant reduction of shunt dependency in a traditionally shunt-dependent population. Further studies are warranted to optimise the algorithm of treatment in these patients.

Randomized clinical trial of prevention of hydrocephalus after intraventricular hemorrhage in preterm infants: brain-washing versus tapping fluid

OBJECTIVE

Hydrocephalus is a serious complication of intraventricular hemorrhage in preterm infants, with adverse consequences from permanent ventriculoperitoneal shunt dependence. The development of hydrocephalus takes several weeks, but no clinical intervention has been shown to reduce shunt surgery in such infants. The aim of this study was to test a new treatment intended to prevent hydrocephalus and shunt dependence after intraventricular hemorrhage.

METHODS

We randomly assigned 70 preterm infants who had gestational ages of 24 to 34 weeks and were progressively enlarging their cerebral ventricles after intraventricular hemorrhage to either (1) drainage, irrigation, and fibrinolytic therapy to wash out blood and cytokines or (2) tapping of cerebrospinal fluid by reservoir as required to control excessive expansion and signs of pressure (standard treatment). We evaluated outcomes at 6 months of age or hospital discharge (if later).

RESULTS

Of 34 infants who were assigned to drainage, irrigation, and fibrinolytic therapy, 2 died and 13 underwent shunt surgery (dead or shunt: 44%). Of 36 infants who were assigned to standard therapy, 5 died and 14 underwent shunt surgery (dead or shunt: 50%). This difference was not significant. Twelve (35%) of 34 infants who received drainage, irrigation, and fibrinolytic therapy had secondary intraventricular hemorrhage compared with 3 (8%) of 36 in the standard group. Secondary intraventricular hemorrhage was associated with an increased risk for subsequent shunt surgery and more blood transfusions.

CONCLUSIONS

Despite its logical basis and encouraging pilot data, drainage, irrigation, and fibrinolytic therapy did not reduce shunt surgery or death when tested in a multicenter, randomized trial. Secondary intraventricular hemorrhage is a major factor that counteracts any possible therapeutic effect from washing out old blood.

ENDOSCOPIC TRANSAQUEDUCTAL REMOVAL OF FOURTH VENTRICULAR NEUROCYSTICERCOSIS WITH AN ANGIOGRAPHIC CATHETER

OBJECTIVE

Fourth ventricular neurocysticercosis (FVNCC) usually presents with obstructive hydrocephalus. Available treatment options are medical, external cerebrospinal fluid diversion, microsurgical, or endoscopic removal alone or in combination. We present our experience of transaqueductal removal of FVNCC by angiographic catheter with endoscopic third ventriculostomy with a rigid endoscope.

METHODS

Ten patients (five male and five female patients; age range, 12-45 yr; mean, 23.2 years) with FVNCC with obstructive hydrocephalus underwent endoscopic removal along with endoscopic third ventriculostomy in a single sitting, through a frontal precoronal burr hole. Diagnosis was established on imaging and confirmed on histology in all of the cases. The Gaab Universal Endoscope System along with 4-mm, 30-degree rigid telescopes was used to enter the third ventricle, and a cut length of angiographic catheter was negotiated through the aqueduct for removal of FVNCC.

RESULTS

Removal of the cyst was performed in all cases. A 30-degree rigid telescope provided excellent image quality, with the ability to address intra-FVNCC through the dilated aqueduct with a curved-tip catheter. None of these patients required any further surgery. There were no significant operative or postoperative complications in any of the cases. All of the patients were asymptomatic, with an average follow-up of 18 months.

CONCLUSION

Transaqueductal removal of an intra-fourth ventricular cyst along with endoscopic third ventriculostomy with a rigid endoscope and catheter is an effective treatment and obviates the need for posterior cranial fossa exploration.

Neuro-endoscopic management of intraventricular neurocysticercosis (NCC)

OBJECTIVE

Various approaches including endoscopy have been used for the treatment of intraventricular and cisternal NCC. We present our technique of Neuro-endoscopic management of intraventricular NCC.

METHODS

Twenty-one cases, 13 females and 8 males (age range 12-50 years; mean, 25.7 years), of intraventricular NCC [lateral (n = 6), third (n = 6), fourth (n = 10) ventricles including a patient with both lateral and third ventricular cysts] producing obstructive hydrocephalus formed the group of study. Gaab Universal Endoscope System along with 4 mm 0 degrees and 30 degrees rigid telescopes were used through a frontal burr-hole for removal of intraventricular including intra-fourth ventricular (n = 10) NCC. Endoscopic third ventriculostomy (ETV) was done for internal cerebrospinal fluid (CSF) diversion. Average follow up was 18 months.

RESULTS

Complete (n = 18) or partial (n = 2) removal of NCC was done in 20 patients, while a cyst located at foramen of Monro slipped and migrated to occipital or temporal horn in 1 patient. Thirty-degree 4-mm rigid telescope provided excellent image quality with ability to address even intra-fourth ventricular NCC through the dilated aqueduct using a curved tip catheter. No patient required further surgery for their hydrocephalus. There was no operative complication and post-operative ventriculitis was not seen in any case despite partial removal of NCC.

CONCLUSION

Neuro-endoscopic surgery is an effective treatment modality for patients with intraventricular NCC. It effectively restores CSF flow and is capable of removing cysts completely or partially from accessible locations causing mass effect. Partial removal or rupture of the cyst does not affect the clinical outcome of the patients.

Endoscopic resection of solid intraventricular brain tumors

OBJECT

Endoscopic removal of intraventricular brain tumors is well established for cystic tumors such as colloid cysts. Aspiration followed by removal or ablation of the membranous wall is possible given the constituent features of these tumors. It is generally expected that endoscopic removal of solid brain tumors from the intraventricular compartment would impose additional technical demands. In this paper, the feasibility and safety of endoscopic removal of solid intraventricular brain tumors is evaluated.

METHODS

Eighty-one patients who underwent endoscopic management of an intraventricular brain tumor were identified from a prospective database. Of these patients, seven underwent attempted endoscopic surgical removal of a solid primary brain tumor. Patient selection, surgical technique, procedure-related morbidity, and extent of removal were reviewed. Five patients underwent complete resection of a solid intraventricular brain tumor, a treatment option that was based on intraoperative assessment and confirmed by postoperative imaging. No patient experienced any procedure-related morbidity. Of the individuals in whom a total endoscopic resection was successful, there has been no symptomatic or radiological evidence of recurrence (mean follow up 20 months). Maximum tumor diameter ranged from 0.5 to 1.8 cm for patients who underwent complete resection, whereas maximum tumor diameter measured 2.4 and 2.5 cm in the two patients in whom a subtotal excision was performed.

CONCLUSIONS

In select patients, complete endoscopic removal of solid intraventricular brain tumors is possible and safe. Factors that influence the ability of a surgeon to perform a complete endoscopic resection include tumor size, composition, and vascularity. The procedure requires careful patient selection, the use of refined endoscopic instrumentation, and a disciplined surgical technique.

Endoscopic management of thalamic gliomas

The management of thalamic gliomas is extremely variable, ranging from radical excision in some cases to more conservative therapy such as a biopsy and radiation. There is a high incidence of associated hydrocephalus. The principles of management are, therefore, histological diagnosis, CSF diversion and adjuvant therapy. Endoscopy appears to offer a new approach to achieve histology and CSF diversion. The various goals achieved with the use of endoscopy in the management of 4 patients with thalamic gliomas are described. With the endoscope we achieved histological diagnoses and CSF diversion was facilitated in all these cases. There were no complications. The advantages of endoscopy in the management of thalamic masses are discussed. Endoscopic intervention appears to offer a modular approach to these lesions.

Patient specific simulation and navigation of ventriculoscopic interventions

In this paper a comprehensive framework for pre-operative planning, procedural skill training, and intraoperative navigation is presented. The goal of this system is to integrate surgical simulation with surgical planning in order to improve the individual treatment of patients. Various surgical approaches and new, more complex procedures can be assessed using a safe and objective platform that will allow the physicians to explore and discuss possible risks and benefits prior to the intervention. A simulation environment extends the pre-operative planning in a natural way, as it allows for direct evaluation of the surgical approach envisioned for each case. In addition, by providing intraoperative navigation based on this simulation, surgeons can carry out the previously optimized plan with higher precision and greater confidence.

Treatment of hydrocephalus with functionally isolated ventricles

Rapid therapeutic drainage of one lateral ventricle may lead to ipsilateral slit ventricle, and the resultant functional obstruction of cerebrospinal fluid flow through the foramen of Monro may cause dilatation of the contralateral ventricle. Drainage of the lateral ventricle with a low-pressure shunt led to functionally isolated contralateral ventriculomegaly in this report. The patient's condition was complicated by a Candida albicans shunt infection. Following effective treatment of the infection by chemotherapy and removal of the shunt system, the patient was treated by bridging two lateral ventricles with ventricular catheters connected to an Ommaya reservoir. An occipital ventricular catheter was then inserted and connected to a programmable valve to drain the bridged lateral ventricles. Modern centers, caring for patients with infantile hydrocephalus, should have endoscopic facilities available but in cases with extensive ventricular adhesions and in asymmetric hydrocephalus where endoscopic septostomy between the ventricles is impossible our described technique may be used.

The use of waterjet dissection in endoscopic neurosurgery

✓Waterjet dissection enables vessel preservation and a reduction in intraoperative blood loss. Because even minimal bleeding should be avoided during neuroendoscopy, the waterjet device may be a particularly valuable tool in such procedures. The authors used this instrument in experimental endoscopic procedures in 20 cadaveric porcine brains and clinically in four patients with obstructive hydrocephalus. A precise and accurate septostomy was achieved in all of the pig brains. In two patients the hydrocephalus was due to intraventricular hemorrhage, in one a posterior fossa tumor, and in one a cystic craniopharyngioma. In all patients the surgical view was kept clear with waterjet irrigation and suction. Using a pressure setting of 10 bars, the waterjet device successfully perforated the cyst wall of the craniopharyngioma in one patient and the floor of the third ventricle in three patients. The use of the waterjet device in selected endoscopic procedures appears safe, and may help reduce intraoperative bleeding. However, further studies are needed to confirm the utility of the waterjet tool in endoscopy.

Two-stage treatment of a tectal ganglioglioma: Endoscopic third ventriculostomy followed by surgical resection

Tumours of the quadrigeminal plate in adults are usually benign. Nevertheless, obstructive hydrocephalus due to compression of the Sylvian aqueduct is an almost invariable early finding. Whether or not direct excision is undertaken, temporary or permanent treatment of the hydrocephalus is warranted. Endoscopic third ventriculostomy is an alternative to insertion of a shunt and provides both acute and long-term relief of hydrocephalus-related symptoms. We chose a two-stage approach for treating a tectal ganglioglioma in an adult: endoscopic third ventriculostomy followed by surgical excision. The advantages and disadvantages of each therapeutic strategy are discussed.

Neurofiberscopic biopsy of tumors of the pineal region and posterior third ventricle: indications, technique, complications, and results

OBJECTIVE

Evaluation of results of the neurofiberscopic biopsy of tumors of the pineal region and posterior third ventricle.

METHODS

From 2001 to 2004, 23 patients (mean age, 30.6 yr) with tumors located in the pineal region or posterior third ventricle underwent neurofiberscopic biopsy with simultaneous third ventriculostomy. The procedure was indicated for verification of the histological diagnosis of the neoplasm, which was planned to be treated by radiotherapy and/or chemotherapy without open surgery (eight patients), establishment of the pathological diagnosis for further choice of the most appropriate treatment strategy (11 patients), differentiation of the recurrent neoplasm and radiation necrosis (two patients), and decompression of the large tumor-associated cyst (two patients). In six previously shunted patients, substitution of the ventriculoperitoneal shunt on the third ventricle stoma was performed.

RESULTS

There was no postoperative mortality or permanent morbidity. In all cases, the obtained tissue sample was sufficient for pathological diagnosis. Transient postoperative complications included fever (15 patients), nausea and vomiting (three patients), and diplopia (one patient). On the long-term follow-up, delayed third ventricular stoma failure caused by tumor regrowth and scar formation was found in one patient, and dissemination of the malignant glioma through the subarachnoid space was found in another patient.

CONCLUSION

Neurofiberscopic biopsy represents a useful method for sampling of tumors of the pineal region and posterior third ventricle, which can be effectively used in both previously shunted and shunt-free patients.

Study of tryptophan metabolism via serotonin in cerebrospinal fluid of patients with noncommunicating hydrocephalus using a new endoscopic technique

By a recent minimally invasive neuroendoscopic technique, the cerebral ventricles have been reached in a quick, reliable, and harmless way, making possible the study of cerebrospinal fluid (CSF) of the lateral ventricles and, above all, the CSF adjacent to the walls of the third ventricle. Tryptophan, 5-hydroxytryptophan, serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) were measured in CSF by HPLC equipment. Twenty-six patients affected with noncommunicating hydrocephalus were enrolled in the study and, as controls, 28 subjects not suffering from any neurological disease. The concentrations of tryptophan were higher in right ventricular CSF than in lumbar CSF (P < 0.01). 5-HT was detectable in the CSF of the right ventricle of hydrocephalic patients. 5-HIAA was higher in right ventricular CSF than in cisternal and lumbar CSF (P < 0.01), both in controls and in hydrocephalic patients. However, there was a higher concentration of 5-HIAA in right ventricular (P < 0.05) and cisternal (P < 0.01) CSF in hydrocephalic patients in comparison with controls. In the CSF samples withdrawn during neuroendoscopy, 5-HT presented the highest concentrations in the pineal recess. The highest amounts of 5-HIAA were found in the choroid plexus, third and right ventricles, pituitary recess, and aqueduct, and the lowest in pineal recess, subarachnoid space, infundibulum, and interpeduncolar cistern. These results provide new insight into the fate of tryptophan and its metabolites via serotonin in the CSF and suggest the feasibility of the new neuroendoscopic technique for brain metabolic studies.

Analysis of dynamic autoregulation assessed by the cuff deflation method

INTRODUCTION

Dynamic testing of cerebral pressure autoregulation is more practical than static testing for critically ill patients. The process of cuff deflation is innocuous in the normal subject, but the systemic and cerebral effects of cuff deflation in severely head-injured patients have not been studied. The purposes of this study were to examine the physiological effects of cuff deflation and to study their impact on the calculation of autoregulatory index (ARI).

METHOD

In 24 severely head-injured patients, 388 thigh cuff deflations were analyzed. The physiological parameters were recorded before, during, and after a transient decrease in blood pressure. Autoregulation was graded by generating an ARI value from 0 to 9.

RESULTS

Mean arterial blood pressure (MAP) dropped rapidly during the first 2-3 seconds, but the nadir MAP was not reached until 8 +/- 7 seconds after the cuff deflation. MAP decreased by an average value of 19 +/- 5 mmHg. Initially the tracings for MAP and cerebral perfusion pressure (CPP) were nearly identical, but after 30 seconds, variable increases in intracranial pressure caused some differences between the MAP and CPP curves. The difference between the ARI values calculated twice using MAP as well as CPP was zero for 70% of left-sided studies and 73% for right-sided studies and less than or equal to 1 for 93% of left- and 95% of right-sided cuff deflations.

CONCLUSION

Transient and relatively minor perturbations were detected in systemic physiology induced by dynamic testing of cerebral pressure autoregulation. Furthermore, this study confirms that the early changes in MAP and CPP after cuff deflation are nearly identical. MAP can substitute for CPP in the calculation of ARI even in the severely brain-injured patient.

Neuroendoscopic Management of Symptomatic Septum Pellucidum Cysts

OBJECTIVE:

Ten rare cases of symptomatic septum pellucidum cysts in patients who underwent endoscopic fenestration are described. The approaches and techniques used in the management of these cysts and the endoscopic surgical indications are discussed.

CLINICAL PRESENTATION:

In the past 5 years, 10 patients (age range, 3–60 yr) with symptomatic septum pellucidum cysts underwent neuroendoscopic fenestration. The most common symptom was intermittent headache (seven patients) accompanied by dizziness, vomiting, and epileptic seizures. Two patients presented with epileptic seizures. One patient presented with abnormally increased head circumference. Magnetic resonance imaging scans of 10 patients showed septum pellucidum cysts, two with hydrocephalus, and two with pituitary microadenoma.

INTERVENTION:

All 10 patients underwent endoscopic fenestration with a rigid endoscope via a frontal approach. Eight cases were performed freehand. Two cases were assisted by a frameless neuronavigation system. Postoperatively, the mass effect of the cysts and the symptoms resolved immediately, and computed tomographic or magnetic resonance imaging scans showed significant decrease in the cyst size and no recurrence during follow-up. Ventricular sizes in the two patients with hydrocephalus were normal.

CONCLUSION:

Neuroendoscopic pellucidotomy could be an effective, safe, and convenient therapeutic method for symptomatic septum pellucidum cysts. This approach might provide communication between the cyst and the ventricular system, thus avoiding shunting or craniotomy. We consider that it is appropriate to use the rigid endoscope via the frontal approach. It is helpful to fill the ventricles with lactated Ringer's solution and leave an external drain after surgery.

Robotic Virtual Endoscopy: Development of a Multidirectional Rigid Endoscope

INTRODUCTION

The use of neuroendoscopy has increased in the past 20 years. Despite an increase in the number of indications for use, novel adjuncts and modifications to existing endoscopes remain all but nonexistent. We introduce a robotic virtual endoscope with applications for neurosurgery that could serve as a novel step in the evolution of future endoscopic technologies.

METHODS

Over the past 8 years, we have worked on the construction of a prototype endoscope with three degrees of freedom that was designed to allow for enhanced safety while maximizing the benefits of virtual field rendition and robotic control. We have developed a prototype to examine a cerebral ventricular model in vitro that functions via either a direct video- or computer-based interface.

RESULTS

Assessment of viewing angulation with robotic feedback has verified the accuracy of the prototype. Models support the ability of the endoscope to localize regions identified via a software interface.

CONCLUSION

The endoscope is a rigid virtual robotic endoscope that provides complete visual coverage of a three-dimensional space by controlling an adjustable viewing direction with three degrees of freedom.

Transparent endoscopic sheath and rigid-rod endoscope used in endoscopic third ventriculostomy for hydrocephalus in the presence of deformed ventricular anatomy

OBJECT

Endoscopic third ventriculostomy (ETV) has been widely performed for the treatment of noncommunicating hydrocephalus. In cases of hydrocephalus in conjunction with deformed and complex ventricular anatomy, it is preferable to use a rigid-rod endoscope for ETV, because the excellent visibility provided by this instrument yields a smooth and correct orientation in the ventricle. The authors report on ETV procedures in which they used a transparent endoscopic sheath that has a common channel in which a rigid-rod endoscope and an instrument can be inserted.

METHODS

In 15 cases of noncommunicating hydrocephalus, a transparent endoscopic sheath and a rigid endoscope were used for ETV. In 11 of the 15 patients, the diameter of the foramen of Monro and the width of the third ventricle were greater than 5 mm, and thus a transparent endoscopic sheath and a rigid endoscope could be smoothly introduced through the foramen of Monro and an ETV successfully performed. Four patients had congenital or acquired narrowing of the foramen of Monro and an anatomically deformed ventricular system. In three of the patients, opening of the narrowed foramen and an ETV were successfully performed using the transparent endoscopic sheath under direct visualization through the rigid-rod endoscope.

CONCLUSIONS

A transparent endoscopic sheath increases safety by offering a corridor to the third ventricle. It also provides excellent visibility without troublesome bleeding from tissues surrounding the foramen of Monro during endoscopic procedures in which a rigid endoscope is used.

The International Infant Hydrocephalus Study: concept and rational

INTRODUCTION

During the recent meetings of the International Study Group on Neuroendoscopy and the International Society for Pediatric Neurosurgery, the consensus view emerged that there is a need to assess the value and efficacy of neuroendoscopic procedures against shunting in a scientific manner, to resolve long-lasting debates on the subject.

MATERIAL AND METHODS

A prospective randomized, controlled trial of endoscopic third ventriculostomy vs shunting in children presenting under the age of 2 years with pure aqueduct stenosis is been proposed and organized (the International Infant Hydrocephalus Study, IIHS). The participating surgeons must adhere to the philosophy of randomization and be suitably experienced in endoscopic techniques in infants. The primary outcome of the trial will be the overall health-related quality of life of these children at 5 years of age. Hence, the study is focusing on the effect of surgery on neurodevelopment, rather than the less important issue of shunt or stoma survival, that has been debated extensively with no conclusion so far. Intention-to-treat analysis will be performed according to the first surgery. Secondary outcomes such as complication and reoperation rate, total hospitalization time and cost, need for repeat imaging, and others will be analyzed as well.

RESULTS

Pure aqueduct stenosis is relatively rare, making recruitment problematic, but has been chosen to avoid other confounding factors that could influence outcome. More than 25 centers worldwide have committed already to patient recruitment to the study. It is anticipated that recruitment will last for 2 years, aiming for 91 patients per arm. The study has started recruiting patients already in some countries.

CONCLUSION

It is hoped that the trial will not only provide answers to unsettled debates on the value of neuroendoscopy but also create a network of collaborating pediatric neurosurgeons for future initiatives.

Recording CSF pressure with a transducer-tipped wire in an animal model of Chiari I

In dogs, a wire with a pressure-sensitive transducer was inserted percutaneously into the subarachnoid space and manipulated under fluoroscopic monitoring in the posterior fossa or upper cervical spinal canal. Pressure recordings from the wire showed fluctuations in pressure corresponding to the cardiac cycle. When a balloon was distended in the foramen magnum, maximum and minimum pressures increased. Continuous monitoring of CSF pressure remote from the site of cannulation was feasible with a wire-based pressure transducer.

Neuroendoscopic Appearance of an Intraventricular Cavernous Angioma Blocking the Foramen of Monro-Case Report-

A 47-year-old woman presented with unilateral ventricular enlargement detected by magnetic resonance imaging during a medical checkup. Neuroendoscopic exploration identified a multilocular lesion in which dark red fluid formed a niveau near the right side of the foramen of Monro. The diagnosis was intraventricular cavernous angioma. Restricted flow of cerebrospinal fluid at the foramen of Monro was observed. Xanthochromia, which seemed to be due to previous bleeding, was observed at the fornix. When the neuroendoscope touched the angioma, the wall collapsed and bled. Endoscopic removal of the angioma was abandoned, and craniotomy and resection of the angioma were performed. No new neurological anomalies were observed after surgery. Preoperative diagnosis of intraventricular cavernous angioma is difficult based on neuroimaging. Neuroendoscopy is effective for diagnosis and the decision-making process regarding treatment.

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.

Neuroendoscopy: past, present, and future

Neuroendoscopy began with a desire to visualize the ventricles and deeper structures of the brain. Unfortunately, the technology available to early neuroendoscopists was not sufficient in most cases for these purposes. The unique perspective that neuroendoscopy offered was not fully realized until key technological advances made reliable and accurate visualization of the brain and ventricles possible. After this technology was incorporated into the device, neuroendoscopic procedures were rediscovered by neurosurgeons. Endoscopic third ventriculostomy and other related procedures are now commonly used to treat a wide array of neurosurgically managed conditions. A seemingly limitless number of neurosurgical applications await the endoscope. In the future, endoscopy is expected to become routine in modern neurosurgical practice and training.

Endoscopic navigation of the fourth ventricle

Transaqueductal navigation of the fourth ventricle has long been considered dangerous and of no clinical relevance. After the refinement of the endoscopic technique and supported by the extensive experience gained at the authors' institution since 1994, endoscopic exploration of the fourth ventricle has been performed by the same surgeon in 54 patients. In all cases reviewed, endoscopic navigation of the fourth ventricle was successfully performed with no related neurological deficit. This preliminary experience shows the feasibility of transaqueductal navigation of the fourth ventricle, which is made possible by the use of small, flexible endoscopes in expert hands.

Hollow mandrin facilitates external ventricular drainage placement

BACKGROUND

Placement of ventricular catheters is a routine procedure in neurosurgery. Ventricle puncture is done using a flexible ventricular catheter stabilised by a solid steel mandrin in order to improve stability during brain penetration. A correct catheter placement is confirmed after removing the solid steel mandrin by observation of cerebrospinal fluid (CSF) flow out of the flexible catheter. Incorrect placement makes further punctures necessary. The newly developed device allows CSF flow observation during the puncture procedure and in addition precise intracranial pressure (ICP) measurement.

METHOD

The developed mandrin is hollow with a blunt tip. On one side 4-5 small holes with a diameter of 0.8 mm are drilled corresponding exactly with the holes in the ventricular catheter, allowing CSF to pass into the hollow mandrin as soon as the ventricle is reached. By connecting a small translucent tube at the distal portion of the hollow mandrin ICP can be measured without loss of CSF. The system has been used in 15 patients with subarachnoid haemorrhage (SAH) or intraventricular haemeorrhage (IVH) and subsequent hydrocephalus.

FINDINGS

The new system improved the external ventricular drainage implantation procedure. In all 15 patients catheter placement was correct. ICP measurement was easy to perform immediately at ventricle puncture. In 4 patients at puncture no spontaneous CSF flow was observed, therefore by connecting a syringe and gentle aspiration of CSF correct placement was confirmed in this unexpected low pressure hydrocephalus. Otherwise by using the conventional technique further punctures would have been necessary.

CONCLUSIONS

Advantages of the new technique are less puncture procedures with a lower risk of damage to neural structures and reduced risk of intracranial haemorrhages. Implantation of the ventricular catheter to far into the brain can be monitored and this complication can be overcome. Using the connected pressure monitoring tube an exact measurement of the opening intracranial pressure can be obtained performed without losing CSF.

Neurofiberscope-guided management of slit-ventricle syndrome due to shunt placement

OBJECT

The purpose of this study was to evaluate an original neurofiberscope-guided strategy for the management of slit-ventricle syndrome that occurs after shunt placement.

METHODS

Between 1995 and 2003 15 patients with slit-ventricle syndrome (mean age 14.2 years) underwent endoscopic third ventriculostomy (ETV) and shunt removal. During the initial surgical procedure a neurofiberscope with a small outer diameter was inserted along the shunt tube into the collapsed ventricle for endoscopically controlled removal of the ventricular catheter and evaluation of brain compliance. If the latter was sufficiently preserved, primary ETV and shunt removal were performed (four cases). If brain compliance seemed to be significantly reduced, endoscopically controlled replacement of the ventricular catheter and implantation of the Codman-Hakim programmable valve shunt device were performed (11 cases). In these patients, delayed ETV and shunt removal were performed later (mean period of 16.3 months). No medical or surgical complications occurred in any case. Follow up ranged from 6 to 84 months (mean 31.1 months; median 22 months). All patients became shunt independent and 13 became symptom free. Overall, the size of the ventricles returned to normal in five cases, became slightly dilated in nine, and moderately dilated in one.

CONCLUSIONS

Neurofiberscope-guided treatment of slit-ventricle syndrome involving shunt removal and ETV appears to be beneficial; all patients in this series were symptom free and shunt independent at the end of follow up.

Bacterial meningitis caused by the use of ventricular or lumbar cerebrospinal fluid catheters

Object. In the present study the authors compared the incidence and risk factors for external drainage—related bacterial meningitis (ED-BM) by using ventricular and lumbar catheters.

Methods. A cohort of 230 consecutive patients with ED was evaluated. Cerebrospinal fluid samples were obtained daily for microbiological culture, and ED-BM was defined based on culture results in combination with clinical symptoms. The incidence of ED-BM was 7% in lumbar and 15% in ventricular drains. Independent risk factors included site leakage, drain blockage, and most importantly duration of ED. Despite a higher infection rate, ventricular catheters did not have a significant higher risk of infection after correcting for duration of drainage.

Conclusions. Analysis of data in the present study showed that the incidence of ED-associated death is low (0.45%) in patients who do not receive continuous antibiotic prophylaxis during ED.

Endoscopic third ventriculostomy for chronic hydrocephalus after tuberculous meningitis

BACKGROUND

Cerebrospinal fluid diversion procedures are indicated in patients with hydrocephalus after tuberculous meningitis (TBM). We present 2 patients with hydrocephalus after TBM who were successfully treated with endoscopic third ventriculostomy (ETV).

METHODS

Two patients had been diagnosed with hydrocephalus after TBM and had undergone ventriculoperitoneal shunt surgery for the same. They presented with multiple episodes of shunt dysfunction. Endoscopic third ventriculostomy was performed (twice for one patient), and the patients were evaluated clinically and radiologically after the procedure.

RESULTS

On long-term clinical follow-up (3 and 2 years, respectively), both patients were asymptomatic after the ETV. The first patient was radiologically evaluated 7 months after the procedure and the second patient 2 years after the procedure. The first patient showed a decrease in ventricular size. The second patient did not show any significant change in the ventricular size.

CONCLUSION

Endoscopic third ventriculostomy can be considered as a safe and long-lasting solution for hydrocephalus after chronic TBM.

Risk of Infection with Prolonged Ventricular Catheterization

OBJECTIVE:

The relationship between extended ventricular catheterization and infection remains controversial. Although studies have substantiated an increasing infection rate with prolonged catheterization, there has been less agreement on whether this trend continues beyond 10 days. Our study reviews the daily infection rate of 595 patients, 213 of whom underwent more than 10 days of catheterization.

METHODS:

All patients who underwent ventricular monitoring in the neurological intensive care unit from 1995 to 2003 at the University of Michigan Health System were reviewed retrospectively. Infection was defined as a positive cerebrospinal fluid culture. Life-table analysis was used to calculate daily hazard (infection) rates. Patient age, sex, diagnosis, catheter exchanges, location of patient during catheter insertion, and cerebrospinal fluid leak were evaluated as risk factors for infection.

RESULTS:

The average patient age was 51.3 years, and 51.3% were male. Duration of catheterization averaged 8.6 days. The overall infection rate was 8.6%. Daily infection rates increased from the onset of catheter insertion but reached a plateau after Day 4, with subsequent rates ranging predominantly between 1 and 2%, even with extended catheterization beyond 10 days. Only ventricular catheters that had been placed at other institutions significantly affected the infection rate.

CONCLUSION:

A relationship between duration of catheterization and infection seems to be present. However, this relationship is not linear. There is an extremely low daily infection rate that rises over the initial 4 days but then remains relatively constant even with prolonged catheter use. Clinical decisions to continue ventricular catheterization should reflect this low daily risk of infection, which does not seem to increase with extended catheter use.

A simplified endoscopic third ventriculostomy under local anesthesia

The aim of this study is the analysis of our experience with awake endoscopic third ventriculostomy (ETVS) in hydrocephalic patients. From September 1994 to December 2001, 24 neuroendoscopic procedures were performed under local anesthesia. Local infiltration was administered using a bupivacaine and lidocaine mixture. Analgesics were titrated to the effect. A free-hand technique with a flexible endoscope was adopted in 24 patients with primitive and secondary (neoplastic) hydrocephalus. ETVS was performed successfully in all cases. No procedure needed to be discontinued due to seizures, bleeding or agitation. Dural incision/coagulation and Fogarty dilatation proved to be the most painful maneuvers requiring, sometimes, supplemental analgesic administration. No intraoperative complications were observed; however, two asymptomatic trajectory hematomas were incidentally discovered two and three days after the operation, respectively. Awake ETVS is a valuable alternative procedure that can be adopted in adult cooperative patients, provided that the procedure is done in an essential and fast way with the free-hand technique, by means of a flexible endoscope, and with the assistance of an anesthesiologist.

Neuroendoscopic basket dilation technique for the fenestration of the ventricular wall or intracranial cysts--technical note

A basket dilation technique has been developed for fenestration of ventricular or cystic walls, using a basket type widely used in the urological field to collect renal or ureteric stones. This technique allows deep-seated structures to be visualized directly through the expanded basket during dilation and the thinnest part of ventricular wall to easily be pierced, cut, and dilated. Fine control can be exerted over expansion pressure through the hand piece directly connected to the basket tip. In addition, the basket can be rotated to cut the floating tissue that must be removed around the stoma. This basket dilation technique is safer than the balloon inflation technique currently used because it allows visualization of deep-seated structures that cannot be seen through the balloon, and should therefore prove useful in third ventriculostomy, plasty of the sylvian aqueduct, and fenestration of intracranial cystic lesions.

Robot-assisted navigated endoscopic ventriculostomy: implementation of a new technology and first clinical results

BACKGROUND

Important landmarks in the evolution of advanced neurosurgical techniques during the past decades include microneurosurgery, neuro-endoscopy and its minimally invasive nature, as well as neuronavigation and advanced intra-operative imaging. With conventional neuroendoscopic techniques, e.g. free-hand endoscopy or the use of mechanical or pneumatic holding devices, a definitive and controlled movement of the endoscope within the brain does depend on the experience and manual skill of the individual neurosurgeon. Therefore, the development of robotic systems to assist surgeons in performing complex neurosurgical procedures is a growing field of interest.

METHOD

With the precision robot "Evolution 1" (U.R.S. Universal Robot Systems, Schwerin, Germany) a new neurosurgical tool has just become available for the precise steering of instruments within the cranium. After preclinical anatomical as well as precision studies the system was used for robot-assisted navigated endoscopic third ventriculostomies in six patients with hydrocephalus related to aqueductal stenosis.

FINDINGS

All robot-assisted navigated endoscopic procedures were successfully completed. The time for the registration procedure and setup of the robot decreased from 60 min. for the first procedure down to 30 min. The time for the surgical part of the neuro-endoscopic procedure itself ranged from 17 to 35 min. During all procedures no system-related complications occurred.

INTERPRETATION

The use of robotic technology for neuro-endoscopic third ventriculostomies is a major step towards the controlled movement of the neuro-endoscope within the cranium. The start up procedure and calibration of the robot is still time consuming, but the real operation time is comparable to free hand neuro-endoscopy. The steering of the endoscope is facilitated and the precision of the endoscopic movements is noteworthy.

A Newly Designed Disposable Introducer Sheath for a Ventricular Fiberscope

We have developed a disposable plastic introducer sheath for use with a flexible endoscope during intraventricular procedures. The sheath is composed of a thin polypropylene tube passing through the center of a plastic stopper. The tube serves as a sheath through which the fiberscope is introduced into the ventricle. The stopper seats in the burr hole and prevents downward and lateral movement of the tube. The sheath can be placed safely in the ventricle with a drainage catheter used as an introducing guide. We used this sheath system in 10 patients and found it very useful. Manipulation of the fiberscope was not hindered, copious irrigation was allowed, and the sheath remained stable on the skull. This new introducer sheath may contribute to the increased use of a flexible endoscope in neuroendoscopic procedures.

Pro and Cons of Different Designs of Rigid Endoscopes

Experience with more than 200 neuroendoscopic procedures taught us the advantages and disadvantages of the different endoscope designs. Using an endoscope with a sheath with separate channels for the endoscope, the instruments as well as for rinsing and suction we found advantages in rinsing properties, handling, and preciseness of instrument steering. On the other hand an endoscope with a sheath with a singular channel for the endoscope itself, the instruments, rinsing, and suction the advantages were better in visualization of the instruments, more available instruments, and easier extraction of larger specimen. The knowledge of these advantages makes it possible to select the adequate endoscope regarding its design, especially in more complicated cases.