Primary hypertension-induced cerebellar encephalopathy causing obstructive hydrocephalus. Case report

Hypertension-induced encephalopathy is a recognized pathological process commonly focused in the parietal and occipital lobes of the cerebral hemispheres. The parenchyma of the posterior fossa is infrequently involved. The authors report on two cases of isolated edema of the cerebellar hemispheres, which occurred in the setting of hypertensive crisis and led to complete obstruction of or significant impingement on the fourth ventricle and potentially lethal hydrocephalus. To the best of the authors' knowledge, these are the first reported cases of hypertensive encephalopathy centered in the posterior fossa. Two patients presented with profound decreases in neurological status subsequent to development of malignant hypertension. Imaging studies revealed diffusely edematous cerebellar hemispheres with effacement of the fourth ventricle, causing dilation of the lateral and third ventricles. Following emergency placement of external ventricular drains, control of systemic blood pressure was accomplished, and neurological functioning returned to baseline. Although neurological deterioration resolved swiftly following placement of ventricular catheters and administration of diuretic agents, systemic blood pressure did not fluctuate with the release of cerebrospinal fluid and resolution of increased intracranial pressure. Decrease in systemic blood pressure lagged well behind improvement in neurological status; the patients remained morbidly hypertensive until systemic blood pressure was controlled with multiple parenteral medications. The authors hypothesize that the development of hypertension beyond the limits of cerebral autoregulation led to breakdown of the blood-brain barrier in the cerebellum and development of posterior fossa edema secondary to the focal transudation of protein and fluid. Correction of the elevated blood pressure led to amelioration of cerebellar edema. In the appropriate clinical setting, hypertension as the inciting cause of cerebellar encephalopathy should be considered.

[External ventricular drainage. Nursing care]

The authors review the anatomy of the ventricular system, Intracranial Pressure and the alteration of ventricular function which leads to the temporary installation of an external drainage system, the complications derived from the installation and maintenance of that system, as well as the care which will be provided to the patient.

[Changes in head circumference and ventricular system size after neuro-endoscopic third ventriculostomy in children]

The aim of the study was to compare changes in the head circumference ventricular system size after neuroendoscopic third ventriculostomy with those following shunt implantation in children suffering from chronic hydrocephalus. The data were analysed to establish criteria of success of neuroendoscopic procedures. In the years 1999-2001 neuroendoscopic third ventriculostomy was performed in 59 children at the Neurosurgery Department of the Research Institute of Polish Mothers' Memorial Hospital. However, the sample analysed in the paper consists of 29 children (16 boys, 13 girls aged from 18 days to 18 years, mean age 7.03, SD = 7.11 years) with chronic hydrocephalus successfully treated with neuroendoscopic procedures. The control group consists of 59 children (31 boys, 28 girls) selected out of 80 patients who underwent primary shunt implantation at the same Neurosurgical Department in the years 1992-1994. The control children (aged from 2 weeks to 9 months, mean age 2 months, SD = 1.92 months) did not need shunt revision during the clinical observation period. The ventricular system size was assessed in terms of the Frontal Index, while postoperative changes in the system size were expressed by the ratio of the Final Frontal Index to the Baseline Frontal Index. If the ventricular system size remained the same, the ratio was 1; if its size decreased after surgery, the ratio was less than 1, while any increases in the system size were reflected by a ratio over 1. Moreover, the head circumference (HC) was measured before and after surgery only in infants and neonates with non-communicating hydrocephalus. HC was expressed in centiles using the centile chart developed by Kurniewicz-Witczakowa for various age and sex groups of Polish children. The analysis included also post-surgery changes in HC over the observation period, in terms of the difference between the baseline HC value and HC measurements in relation to the observation period duration. A positive sign of this index evidenced a decrease in the rate of HC enlargement, while a negative sign--an increased rate of HC growth. The mean HC at the end of the observation period was 72.96 centile in the neuroendoscopy group and 52.36 centile in children after shunt implantation. The reduction of head circumference following neuroendoscopic procedures was significantly smaller than that after shunt implantation, as the average decrease in HC after neuroendoscopy was only 0.4 centile as compared to about 18 centiles after shunt implantation. In the neuroendoscopy group a relationship was found between HC and age: in newborns HC was significantly smaller than that in infants (20.25 and 82.55 centiles, respectively). An analysis of HC changes (in centiles) in relation to the time since the surgery in all the children aged under 1 year, successfully treated with neuroendoscopic procedures, indicated no tendency to a steady increase in the rate of HC enlargement, even though in many cases the HC after surgery was larger than that prior to the surgery. As regards changes in the ventricular system size, the average ratio of Final to Baseline Frontal Index was 0.9 in the neuroendoscopy group and 0.5 in the group after shunt implantation. The ventricular system turned out to be significantly larger in infants after neuroendoscopy than in other age groups (the mean Frontal Index values were 0.65 vs. 0.53, respectively). No tendency to constant enlargement of the ventricular system size after neuroendoscopy was found. In children with non-communicating hydrocephalus due to Chiarii II malformation a mild enlargement of the ventricular system was seen after successful neuroscopy (the ratio of the Final to Baseline Frontal Index amounted to 1.3).

CONCLUSIONS

The rate of head circumference (HC) enlargement in infants after succeeded neuroendoscopic procedures did not continually increase during the postoperative period, although their HC expressed in centiles could be higher than that before surgery. The average reduction of the ventricular system size was much smaller after neuroendoscopic ventriculostomy than than after shunt implantations. In children with Chiarii II malformation and in infants the ventricle system size may be somewhat increased in comparison to pre-operative levels. However, no tendency to a steady enlargement with time was found either in the HC or in the ventricle system size.

The Seldinger technique for insertion of difficult to place ventricular catheters

BACKGROUND

Multiloculated ventricular hydrocephalus is a difficult pathology for neurosurgeons to treat. Not only are the shunts for this condition prone to malfunction, but they are also difficult to place.

METHODS

The Seldinger technique is used in combination with a rigid scope with a working channel. A soft filiform wire or a thick suture is inserted through the channel. The scope is withdrawn and a ventricular catheter is slid down the wire. The remainder of the shunt is inserted in the usual fashion.

RESULTS

We have not encountered any neurologic compromise from this technique. No bleeding was encountered with the described technique.

CONCLUSION

The Seldinger technique with appropriate types of guide wires and in combination with an endoscope is a useful technique for difficult to place shunts.

Shunting to the sagittal sinus

OBJECTIVES

To develop a shunt that drains CSF from the ventricles to the sagittal sinus under normal-physiological conditions. This shunting principle will not lead to any over-drainage, and a large proportion of the known shunt-complications will be avoided.

METHODS

On the basis of the normal values for ICP, resistance to outflow and the production rate of CSF we have developed a shunt that drains CSF to the sagittal sinus and restores normal condition for the CSF dynamics. The shunt consists of two unidirectional valves, a pre-chamber, a resistance tube made of titanium, and a titanium tube leading CSF into the sagittal sinus. The shunt has been tested in 18 patients. Observation time ranged from 2 to 430 days, mean time 54 days.

RESULTS

The first results from the use of the new shunt are very promising. It has an immediate effect on the clinical symptoms, it restores CSF dynamics (investigated with the shunt inserted) and the size of the ventricles is only gradually diminished. Slit ventricles have not yet been observed. In all patients the symptoms of hydrocephalus were relieved. No occlusion or thrombosis of the sagittal sinus have been observed. This is in agreement with the reports in the literature of shunting to the sagittal sinus, where 99 cases have been presented with an observation period of up to 6 years. The shunt has proven easy and safe to implant.

CONCLUSIONS

Shunting to the sagittal sinus has proven easy and safe with regard to short term results. By using a dedicated shunt that drains at normal physiological parameters for the CSF dynamics any over-drainage is avoided, and it may be expected that the complication rate will be substantially smaller than with existing shunting systems.

[Endoscopic third ventriculostomy for management of obstructive hydrocephalus secondary to supratentorial intraventricular hematoma. Case report]

We report two cases of intraventricular hematoma with obstructive hydrocephalus. We perform endoscopic treatment of the hydrocephalus: aspiration of the hematoma associated with a third ventriculostomy. Both patients respectively aged 59 and 74 years had an obstructive hydrocephalus due to intraventricular hemorrage. The patient neurological status worsen at day 6 for patient No. 1 and at day 4 for patient No. 2. Endoscopic ventriculoscopy was performed respectively at day 6 and at day 5. Operatively, immediate vision was poor but was progressively improved by repetitive irrigation with Ringer-lactate (RL). Obstruction of the right Monro foramen by clot was observed. Introduction of the neuroendoscope into the third ventricle was possible after suction of the hematoma. Perforation of the floor of the third ventricle was performed after identification of the mammillary bodies and the infundibulum. Neurological status recovered within 10 days after surgery and the patients were referred to a medical unit. The patients were independent at home. The one-year MRI follow-up study showed a functional acqueduc in case 1 and a non-functional acqueduc in case 2 indicating in this case that the ventriculocisternotomy was useful. Intraventricular hematoma is not a contraindication for endoscopic third ventriculostomy. If possible, waiting for 6 or 5 days to allow the structuring of the blood clot and using large irrigation RL may facilitate the endoscopic procedure. This indication for endoscopic third ventriculostomy constitutes an alternative to external ventricular drainage which is significatively associated with complication (infection and obstruction). We cannot affirm that the removal of the clots and ventriculocisternostomy versus temporary external drainage avoids secondary hydrocephalus.

Implementation, calibration and accuracy testing of an image-enhanced endoscopy system

This paper presents a new method for image-guided surgery called image-enhanced endoscopy. Registered real and virtual endoscopic images (perspective volume renderings generated from the same view as the endoscope camera using a preoperative image) are displayed simultaneously; when combined with the ability to vary tissue transparency in the virtual images, this provides surgeons with the ability to see beyond visible surfaces and, thus, provides additional exposure during surgery. A mount with four photoreflective spheres is rigidly attached to the endoscope and its position and orientation is tracked using an optical position sensor. Generation of virtual images that are accurately registered to the real endoscopic images requires calibration of the tracked endoscope. The calibration process determines intrinsic parameters (that represent the projection of three-dimensional points onto the two-dimensional endoscope camera imaging plane) and extrinsic parameters (that represent the transformation from the coordinate system of the tracker mount attached to the endoscope to the coordinate system of the endoscope camera), and determines radial lens distortion. The calibration routine is fast, automatic, accurate and reliable, and is insensitive to rotational orientation of the endoscope. The routine automatically detects, localizes, and identifies dots in a video image snapshot of the calibration target grid and determines the calibration parameters from the sets of known physical coordinates and localized image coordinates of the target grid dots. Using nonlinear lens-distortion correction, which can be performed at real-time rates (30 frames per second), the mean projection error is less than 0.5 mm at distances up to 25 mm from the endoscope tip, and less than 1.0 mm up to 45 mm. Experimental measurements and point-based registration error theory show that the tracking error is about 0.5-0.7 mm at the tip of the endoscope and less than 0.9 mm for all points in the field of view of the endoscope camera at a distance of up to 65 mm from the tip. It is probable that much of the projection error is due to endoscope tracking error rather than calibration error. Two examples of clinical applications are presented to illustrate the usefulness of image-enhanced endoscopy. This method is a useful addition to conventional image-guidance systems, which generally show only the position of the tip (and sometimes the orientation) of a surgical instrument or probe on reformatted image slices.

Failure of regular external ventricular drain exchange to reduce cerebrospinal fluid infection: result of a randomised controlled trial

BACKGROUND

It is controversial whether regular changes of external ventricular drains can reduce cerebrospinal fluid (CSF) infection.

OBJECTIVE

To carry out a randomised controlled clinical trial over a two year period to determine whether a regular change of ventricular catheter every five days could reduce CSF infection and improve outcome.

METHODS

103 patients requiring external ventricular drains for more than five days and with no evidence of concurrent CSF infection were studied. The patients were randomised to regular change of ventricular catheter (every five days) and no change unless clinically indicated.

RESULTS

The CSF infection rates were 7.8% for the catheter change group and 3.8% for the no change group, respectively (rate ratio = 1.80, 95% confidence interval 0.33 to 9.81, p = 0.50). No significant difference was found in intensive care unit stay, ward stay, or clinical outcome between the two groups.

CONCLUSIONS

Regular changes of ventricular catheter at five day intervals did not reduce the risk of CSF infection. A single external ventricular drain can be employed for as long as clinically indicated.

Burr hole cover for ventriculoperitoneal shunts and ventriculostomy: technical note

In patients who have undergone intracranial procedures, bone gaps or burr holes often result in small but undesirable scalp or skin depressions. The authors designed a burr hole cover for hydrocephalus shunt system or external ventricular drainage, which is shaped to alleviate the deformity of the burr hole by filling the bone defect and allowing the passage of the ventricular catheter. The specifications of this device and its clinical application are described.

Ventriculostomy-related infections: a critical review of the literature

OBJECTIVE

To provide a critical evaluation of the published literature describing risk factors for ventriculostomy-related infections (VRIs) and the efficacy of prophylactic catheter exchange.

METHODS

A MEDLINE literature search was performed, and data were extracted from studies published from 1941 through 2001.

RESULTS

Published criteria for diagnosing VRIs are highly variable. Intraventricular hemorrhage, subarachnoid hemorrhage, cranial fracture with cerebrospinal fluid leak, craniotomy, systemic infections, and catheter irrigation all predispose patients to the development of VRIs. Extended duration of catheterization is correlated with an increasing risk of cerebrospinal fluid infections during the first 10 days of catheterization. Prophylactic catheter exchange does not modify the risk of developing later VRIs in retrospective studies.

CONCLUSION

Categorizing suspected cerebrospinal fluid infections as contaminants, colonization, suspected or confirmed VRIs, or ventriculitis more accurately describes the patient's clinical condition and may indicate different management strategies. A prospective, randomized clinical trial is required to further evaluate the efficacy of prophylactic catheter exchange in limiting the incidence of VRIs during prolonged catheterization. Although prophylactic catheter exchange remains a practice option, the available data suggest that this procedure is not currently justified.

[Endoscopic ventriculostomy of the third ventricle in adults. Own experience]

Only few reports can be found on endoscopic third ventriculostomy (ETV) in the Polish literature, and the majority of other reports concern paediatric or mixed population. This has induced the authors to report their experience with ETV in adults, reporting the results and discussing the usefulness and effectiveness of this procedure, causes of complications and failure. ETV was carried out in 20 patients aged over 18 years in a two-year period, beginning in 1999. In 13 cases (64%) the cause was external compression of CSF system by tumour leading to hydrocephalus. In 3 cases aqueduct stenosis was producing hydrocephalus, in 3 cases arachnoid cyst, perisellar or situated in posterior part of the third ventricle, was the cause, and in one case colloidal cyst of the third ventricle. The outcome were analysed according to clinical and radiological criteria finding that the ETV was successful in 90% of cases by clinical criteria, and in 88% by radiological criteria. Only unimportant clinical complications were reported without major consequences. It is concluded that ETV is a very useful method for hydrocephalus treatment in adults, especially if caused by blockade of CSF pathways by tumour or arachnoid cysts in the vicinity of the third ventricle.

Novel multipurpose bipolar instrument for endoscopic neurosurgery

OBJECTIVE

Hemorrhage control in endoscopic neurosurgery is critical because of the lack of suitable instruments for coagulation. One reason for this problem is that miniaturization of the instruments is still a technical problem. In this article, we present a solution: the use of bipolar microforceps with a small diameter of 1.5 mm.

METHODS

With the use of modern synthetic and metallic materials, the construction of the bipolar microforceps was designed without the use of mechanical joints. All movable elements are integrated within the instrument shaft. This design provides optimal visibility of the operating field because the sheath has a diameter of only 1.5 mm along its entire length. Therefore, this instrument is compatible with most working channels of neuroendoscopes.

RESULTS

The new, joint-free design of the forceps and the electric insulation of the branches were the technical innovations that led to the development of this novel, multipurpose instrument.

CONCLUSION

This new instrument may enhance endoscopic resection and shrinkage of cystic lesions and may offer new possibilities in endoscopic tumor resection and the treatment of hemorrhage.

Endoscopic reverse third ventriculostomy via the cisterna magna: anatomical study and proposal of a novel procedure

Basilar artery injury has been known as a potential lethal complication of endoscopic third ventriculostomy. In order to avoid this complication, endoscopic reverse third ventriculostomy via a trans-cisterna-magna route was studied. A cadaveric study was performed for navigation of a flexible endoscope through the cisterna magna. Three fresh, unfixed cadavers were used for this endoscopic navigation. In the prone position, a small vertical paramedian skin incision is made at the mid-portion of the posterior neck. An 11-mm threaded plastic tube is inserted towards the posterior arch of the atlas. After a partial hemilaminectomy of the atlas, a flexible endoscope is introduced into the cisterna magna and is navigated cephalad along the vertebrobasilar artery to the inferior aspect of the floor of the third ventricle. Through the working channel of a fiberscope, third ventriculostomy is performed in a reverse direction. Additional detailed anatomy was studied in fixed cadaveric head specimens with a rigid rod-lens endoscope for anatomic orientation. A novel technique of a trans-cisterna-magna reverse third ventriculostomy was studied in cadaveric specimens. This technique may avoid basilar artery injury which occurs occasionally during conventional third ventriculostomy.

A new method of ultrasonic guidance of neuroendoscopic procedures. Technical note

The authors present a newly designed device for ultrasonic guidance of neuroendoscopic procedures. It consists of a puncture adapter that attaches to a rigid endoscope having an outer diameter of 6 mm and is mounted on a small, bayonet-shaped ultrasound probe. This adapter directs the movement of the endoscope precisely within the ultrasonic field of view. The targeted region is identified by transdural insonation via an enlarged single burr-hole approach, and the endoscope is tracked in real time throughout its approach to the target. The procedure has been performed in 10 patients: endoscopic ventriculocystostomy in four cases; removal of a colloid cyst of the third ventricle in two cases; and intraventricular tumor biopsy, intraventricular tumor resection, third ventriculostomy, and removal of an intraventricular hematoma in one case each. The endoscope was depicted on ultrasonograms as a hyperechoic line without disturbing echoes and, consequently, the target (cyst, ventricle, or tumor) was safely identified in all but one case, in which intraventricular air hid a colloid cyst in the foramen of Monro. The method presented by the authors proved to be very effective in the guidance and control of neuroendoscopic procedures. Combining this method with image guidance is recommended to define the entry point of the endoscope precisely.

The application of controlled intracranial hypertension in slit ventricle syndrome patients with obstructive hydrocephalus and shunt malfunction

When a shunted patient with slit-ventricle syndrome (SVS) presents with a shunt malfunction or infection, the third ventricle may not be of sufficient caliber, despite the shunt malfunction, to allow atraumatic passage of an endoscope to the floor of the third ventricle. We describe four slit ventricle syndrome patients with respectively 24, 12, 18 and 2 prior shunt revisions who presented with shunt infection. In each patient the shunt was externalized and controlled intracranial hypertension (CIH) was applied over an average of 5.8 days by raising the height of the external ventricular drain (EVD) bag to a mean height of 18.8 cm above EAM. This increased the mean transverse third ventricular diameter from an average of 0.28 cm on admission to 1.13 cm after application of CIH. Endoscopic third ventriculocisternostomy (ETV) was satisfactorily performed in three of the four patients who remain shunt free after a mean follow-up of 21.3 months. CIH followed by ETV is an option in selected SVS patients who present with shunt malfunction or infection.

Virtual MRI endoscopy: detection of anomalies of the ventricular anatomy and its possible role as a presurgical planning tool for endoscopic third ventriculostomy

BACKGROUND

Many anatomical anomalies have the potential to impair the efficacy of endoscopic third ventriculostomy (ETV) and increase the surgical morbidity. By virtual magnetic resonance imaging (MRI) endoscopy, the real endoscopic view into the ventricular system can be simulated. It was the objective of the present study to investigate if this simulation is sensitive enough to detect anatomical anomalies of the ventricular system.

METHOD

In 18 hydrocephalic patients, first neuronavigationally guided ETV, then virtual MRI endoscopy were performed. This study design allowed for selection of a path for virtual MRI endoscopy, which was identical to that used during surgery, making the real and the virtual view on anatomical structures of the ventricular system highly comparable. It was investigated whether the intra-operatively identified anatomical anomalies could likewise be depicted on virtual MR endoscopic images.

FINDINGS

Seven anatomical variants (not enlarged interventricular foramen n=2, atrophic corpus callosum and split fornical bodies n=1, narrow retroclival space n=1, prominent basilar tip n=1, opaque and thick/atypically declining third ventricular floor n=2) were encountered in 5 of the 18 patients during surgery. The five variants of the non-membraneous structures were identified by virtual MRI endoscopy (sensitivity 71%), whereas the anatomical variants of the third ventricular floor were missed. Both the normal as well as the variant third ventricular floor could not be visualised and appeared as a defect. Through this artefact, the anatomy of the major vessels in the interpeduncular cistern could be assessed.

INTERPRETATION

The sensitivity of virtual MRI endoscopy for detection of anatomical variants of the ventricular system is low. Its potential usefulness as a presurgical planning tool inspite of this low sensitivity rate is discussed.

Third ventriculostomy

Since its description by Dandy in 1922, several techniques have been used to perform third ventriculostomy under endoscopic control. Except for the blunt technique, in which the endoscope is used by itself to create the opening in the floor of the third ventricle, the other techniques require more than one instrument to perforate the floor of the ventricle and enlarge the ventriculostomy. The new device described is a sterilizable modified forceps that allows both the opening of the floor and the enlargement of the ventriculostomy in a simple and effective way. The new device has the following characteristics: 1) the tip of the forceps is thin enough to allow the easy perforation of the floor of the ventricle; 2) the inner surface of the jaws is smooth to avoid catching vessels of the basal cistern; and 3) the outer surface of the jaws has indentations that catch the edges of the opening to prevent them from slipping along the instrument's jaws. The ventricle floor is opened by gentle pressure of the forceps, which is slowly opened so that the edges of the aperture are caught by the distal outer indentation of the jaws, leading to an approximately 4-mm opening of the floor. This device has been used successfully in 10 consecutive patients. This new device allows surgeons to perform third ventriculostomy under endoscopic control in a very simple, quick, and effective way, avoiding the need for additional single-use instruments.

Frameless navigation and endoscopy

OBJECT

Frameless computerized neuronavigation has been increasingly used in intracranial endoscopic neurosurgery. However, clear indications for the application of neuronavigation in neuroendoscopy have not yet been defined. The purpose of this study was to determine in which intracranial neuroendoscopic procedures frameless neuronavigation is necessary and really beneficial compared with a free-hand endoscopic approach.

METHODS

A frameless infrared-based computerized neuronavi- gation system was used in 44 patients who underwent intracranial endoscopic procedures, including 13 third ventriculostomies, nine aqueductoplasties. eight intraventricular tumor biopsy procedures or resections, six cystocisternostomies in arachnoid cysts, five colloid cyst removals, four septostomies in multiloculated hydrocephalus, four cystoventriculostomies in intraparenchymal cysts, two aqueductal stent placements, and fenestration of one pineal cyst and one cavum veli interpositi. All interventions were successfully accomplished. In all procedures, the navigational system guided the surgeons precisely to the target. Navigational tracking was helpful in entering small ventricles, in approaching the posterior third ventricle when the foramen of Monro was narrow, and in selecting the best approach to colloid cysts. Neuronavigation was essential in some cystic lesions lacking clear landmarks, such as intraparenchymal cysts or multiloculated hydrocephalus. Neuronavigation was not necessary in standard third ventriculostomies, tumor biopsy procedures, and large sylvian arachnoid cysts, or for approaching the posterior third ventricle when the foramen of Monro was enlarged.

CONCLUSIONS

Frameless neuronavigation has proven to be accurate, reliable, and extremely useful in selected intracranial neuroendoscopic procedures. Image-guided neuroendoscopy improved the accuracy of the endoscopic approach and minimized brain trauma.

Treatment of post-haemorrhage ventricular dilatation with an Ommaya's reservoir: management and outcome of 64 preterm infants

Over a 5-year period, an Ommaya's reservoir has been inserted in a single neurosurgical centre in each of 64 preterm infants with post-haemorrhage ventricular dilatation (PHVD). Their mean gestational age at birth was 29.2 weeks. The average age at reservoir insertion was 24 days. Seventeen infants received a fibrinolytic agent through the reservoir. Infections occurred in 14 patients. Two patients died after handling of their reservoirs. Thirty-one of the 45 survivors required a shunt placement. After a follow-up ranging from 6 months to more than 4 years, 17 of 43 patients have severe sequelae or are handicapped. Compared with the results of other studies, our experience does not suggest that treatment of PHVD with an Ommaya's reservoir is beneficial in term of mortality, shunt placement, and/or neurological outcome. The place of Ommaya's reservoir among the various means of managing PHVD should be carefully evaluated, as should the best way of using this appliance safely.

Experimental evaluation of the Spiegelberg intracranial pressure and intracranial compliance monitor. Technical note

The goal of this study was to compare the Spiegelberg intraventricular intracranial pressure (ICP)/intracranial compliance monitoring device, which features an air-pouch balloon catheter, with existing gold-standard methods of measuring ICP and intracranial compliance. A Spiegelberg intraventricular catheter, a standard intraventricular catheter, and a Codman intraparenchymal ICP microsensor were placed in five sheep, which previously had been given anesthetic and paralytic agents, to allow comparative measurement of ICP at incremental levels (range 5-50 mm Hg). Intracranial pressure measured using the Spiegelberg intraventricular air-pouch balloon catheter displayed a linear correlation with ICP measured using the standard intraventricular fluid-filled catheter (r2 = 0.9846, p < 0.001; average bias -0.74 mm Hg), as well as with ICP measured using the Codman intraparenchymal strain-gauge sensor (r2 = 0.9778, p < 0.001; average bias 0.01 mm Hg). Automated measurements of intraventricular compliance obtained using the Spiegelberg compliance device were compared with compliance measurements that were made using the gold-standard manual cerebrospinal fluid bolus injection technique at ICPs ranging from 5 to 50 mm Hg, and a linear correlation was demonstrated between the two methods (r2 = 0.7752, p < 0.001; average bias -0.019 ml/mm Hg). The Spiegelberg air-pouch ICP/compliance monitor provides ICP and compliance data that are very similar to those obtained using both gold-standard methods and an intraparenchymal ICP monitor over a range of pathophysiological ICPs. The automated closed Spiegelberg system offers practical advantages for the measurement of intraventricular compliance. Assessment of the clinical utility and robustness of the Spiegelberg system, together with the development of an intraparenchymal device, would enhance the clinical utility of automated compliance measurement and expand the range of its applications.