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.

Factors affecting excitatory amino acid release following severe human head injury

OBJECT

Recent animal studies demonstrate that excitatory amino acids (EAAs) play a major role in neuronal damage after brain trauma and ischemia. However, the role of EAAs in patients who have suffered severe head injury is not understood. Excess quantities of glutamate in the extracellular space may lead to uncontrolled shifts of sodium, potassium, and calcium, disrupting ionic homeostasis, which may lead to severe cell swelling and cell death. The authors evaluated the role of EEAs in human traumatic brain injury.

METHODS

In 80 consecutive severely head injured patients, a microdialysis probe was placed into the gray matter along with a ventriculostomy catheter or an intracranial pressure (ICP) monitor for 4 days. Levels of EAAs and structural amino acids were analyzed using high-performance liquid chromatography. Multifactorial analysis of the amino acid pattern was performed and its correlations with clinical parameters and outcome were tested. The levels of EAAs were increased up to 50 times normal in 30% of the patients and were significantly correlated to levels of structural amino acids both in each patient and across the whole group (p < 0.01). Secondary ischemic brain injury and focal contusions were most strongly associated with high EAA levels (27+/-22 micromol/L). Sustained high ICP and poor outcome were significantly correlated to high levels of EAAs (glutamate > 20 micromol/L; p < 0.01).

CONCLUSIONS

The release of EAAs is closely linked to the release of structural amino acids and may thus reflect nonspecific development of membrane micropores, rather than presynaptic neuronal vesicular exocytosis. The magnitude of EAA release in patients with focal contusions and ischemic events may be sufficient to exacerbate neuronal damage, and these patients may be the best candidates for treatment with glutamate antagonists in the future.

Management of hydrocephalus by endoscopic third ventriculostomy in patients with myelomeningocele

Endoscopic third ventriculostomy (ETV) was performed between July 1978 and July 1995 on 69 patients with hydrocephalus and myelomeningocele. Most of the patients had been previously shunted, although in 14 patients ETV was the initial treatment. Patient selection was based on preoperative imaging studies suggesting noncommunicating hydrocephalus. Only 2 patients exhibited transient hypothalamic dysfunction with complete resolution. Patients were assessed by their clinical status, imaging characteristics, and, in some cases, formal psychometric studies. The overall success rate was 72%, although selecting only patients who have been previously shunted or who were over 6 months of age at the time of endoscopy increases this to 80%. Our results indicate that ETV is a safe and effective means of treating hydrocephalus in the older spina bifida population and offers the hope of long-term, shunt-independent life for selected patients.

Relative risks of ventriculostomy infection and morbidity

Ventricular catheter placement is a common procedure for the management of increased intracranial pressure. Hypotheses regarding the etiology of infection of catheters center on two alternative assumptions: 1) contamination leading to infection occurs at the time of catheter insertion, implying that catheter duration has minimal effect on infection risk; and 2) infection of catheters derives from catheter contamination after insertion, suggesting that duration of catheter use may significantly affect infection risk. We have studied the relative complication rate of ventricular catheter insertions using a retrospective approach (n = 161 patients and 253 catheter insertion procedures). The overall infection rate was 4.1%, but the daily infection hazard increased exponentially with time, to a maximum daily rate of 10.3% by day 6 of catheter insertion. This increasing risk appears most consistent with the second hypothesis. The risk of non-infectious complications was 5.6%, including hemorrhagic occurrences and misplacement severe enough to require a new catheter insertion. The daily hazard of infection approximately equalled the non-infectious risk of routine catheter replacement by day 5. Additional prospective data on the daily risk of CSF infection and the appropriateness of antibiotic prophylaxis either at the time of ventricular catheter insertion or continued through the catheter's presence may be required to both definitively identify which hypothesis of infection risk is correct and whether antibiotics can significantly ameliorate this risk.

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.

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.

Continuous-pressure controlled, external ventricular drainage for treatment of acute hydrocephalus--evaluation of risk factors

Experience with a continuous-pressure controlled, external ventricular drainage system (EVD) in 100 patients (n = 49 female, n = 51 male; mean age, 56.3 yr) with acute hydrocephalus is reported. Cerebrospinal fluid circulation disturbances resulted from hemorrhages caused by subarachnoid hemorrhage (n = 45), parenchymal hemorrhages from angioma (n = 4), anticoagulants (n = 7), or hypertension or other reasons (n = 30); in addition, hydrocephalus developed from infections (n = 3), tumors (n = 2), infratentorial infarction (n = 5), or unknown reasons (n = 4); 52 patients had ventricular hemorrhages. No patient died of system-associated morbidity. Mean time of EVD treatment was 9.5 days, with 40 patients being treated for 10 to 29 days; routine refobacin (5 mg) flushing of the system was performed three times a day. Patients without cerebrospinal fluid leakage had a 2% rate of secondary infection compared with 13% in patients with cerebrospinal fluid leakage due to ventricular catheter placement (P < 0.05; overall infection rate, 5%). A clinical mortality rate of 29% during EVD treatment was observed in subarachnoid hemorrhage patients (Hunt and Hess Grades II, III, IV, and V; n = 9, 9, 18, and 9, respectively); recurrent hemorrhages during EVD treatment occurred in 19 patients (26 hemorrhages), and of these, 10 patients died. System occlusion was seen in 19 cases (12 of 45 patients with subarachnoid hemorrhage), requiring catheter and system renewal in 1 case; system extraction was seen in 3 cases, misplacement was seen in 11 cases, and disconnection was seen in 5 cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Results of routine ventriculostomy with external ventricular drainage for acute hydrocephalus following subarachnoid haemorrhage

We reviewed the results of ventriculostomy with external ventricular drainage in patients with acute hydrocephalus complicating subarachnoid haemorrhage. Of 194 consecutive patients with subarachnoid haemorrhage admitted during the past eight years, 52 (27%) developed hydrocephalus within 72 hours of the ictus. Patients with acute hydrocephalus were in grades III to V (Hunt and Hess) at the time of evaluation and all patients with hydrocephalus underwent ventriculostomy within 24 hours of diagnosis. Twenty-six patients improved within 24 hours of cerebrospinal fluid drainage and 17 of these patients underwent surgery, nine of whom did well (Glasgow Outcome Scale 1 and 2). All 18 patients who did not improve within this period, including one who worsened, died. In eight patients the response to ventriculostomy was considered as undetermined, because of the proximity of the drain insertion to a definitive surgical procedure, and all of them had an excellent outcome (Glasgow Outcome Scale 1). Of 32 patients in grades IV and V, 17 did not improve and all of them died. Eight of the 15 patients in these grades, who were in the improved or undetermined categories, did well. Five patients (10%) developed meningitis. All patients with this complication had drainage for more than four days. Seven patients (14%) had a rebleed during the drainage. All except one patient with a rebleed had no surgery or delayed surgery and in six of them recurrent haemorrhages occurred after more than 24 hours of drainage. We conclude that routine ventriculostomy with external ventricular drainage should be considered for all patients with altered sensorium and acute hydrocephalus following subarachnoid haemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Complications of endoscopic neurosurgery

Neuroendoscopy is rapidly becoming an essential part of the neurosurgeon's repertoire. Currently, very few studies have identified the complications of this new technique, yet many have warned of the steep learning curve associated with its practice. We have reviewed the last 173 neuroendoscopic procedures performed by one surgeon and identified two distinct groups of complications: those that have clinically significant sequelae and those that cause concern intraoperatively but no overt clinical problems. The 173 procedures were performed on 152 patients. Of these patients, 11 suffered significant complications (7%). Twenty-two of the procedures were complicated by intraoperative problems (13%). The incidence of insignificant complications appeared to decrease with experience, whereas that of the significant ones did not. These complications occurred in association with a wide variety of operations over a 2-year period. We conclude that neuroendoscopy is a relatively safe technique with an overall 7% complication rate and a steep learning curve, and that, with a few simple guidelines, it can be employed by all neurosurgeons for the betterment of their patients.

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.

Laboratory testing of three intracranial pressure microtransducers: technical report

Three comparatively priced intracranial pressure (ICP) microtransducers are now available, each characterized by the manufacturer as having very low zero drift over long periods, an excellent frequency response, and a low measurement error. The three microtransducers, coded Transducer A (Camino OLM ICP monitor; Camino Laboratories, San Diego, CA), Transducer B (Codman Microsensor ICP Transducer; Codman & Shurtlef Inc., Randolph, MA), and Transducer C (ICP Monitoring Catheter Kit OPX-SD [4F]; InnerSpace Medical, Irvine, CA), were examined in a pressure-flow test rig designed for assessment of hydrocephalus shunts. All three microtransducers compiled with the manufacturers' specifications and gave high-quality readings under test conditions. However, some differences were noted; Transducer C had the lowest 24-hour zero drift (drifts in all transducers were < 0.8 mm Hg). The temperature drift was very low in Transducer B and C, but Transducer A had a significantly higher drift (0.27 mm Hg/degrees C). Transducer A had a static error < 0.3 mm Hg, Transducer B < 2 mm Hg, and Transducer C < 8 mm Hg. Frequency detection in Transducers A and B were very good (bandwidth, > 30 Hz), whereas Transducer C had a limited bandwidth of 20 Hz. Transducer B scored the best overall, but all three scored satisfactorily during bench testing.

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.

A near-fatal complication of endoscopic third ventriculostomy: case report

The authors treated a 14-year-old girl with posthemorrhagic hydrocephalus and an infected ventriculopleural shunt. She was taken for endoscopic third ventriculostomy with the hope of removing the hardware entirely, but she developed an arrhythmia and hypertension, followed rapidly by complete cardiac arrest. She was resuscitated successfully, made a complete recovery, and subsequently underwent a conventional shunt replacement. This is a newly reported life-threatening complication of neuroendoscopy that must be anticipated by any surgeon undertaking such a procedure.

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.

Change in ventricular size and effect of ventricular catheter placement in pediatric patients with shunted hydrocephalus

OBJECTIVE

The multicenter, randomized pediatric cerebrospinal fluid shunt valve design trial found no difference in the rate of shunt failure between a standard valve, a siphon-reducing valve (Delta; Medtronic PS Medical, Goleta, CA), and a flow-limiting valve (Orbis Sigma; Cordis, Miami, FL); however, the valves were expected to have different effects on ultimate ventricular size. Also, the catheter position or local environment of the ventricular catheter tip might have affected shunt failure. Therefore, we performed a post hoc analysis to understand what factors, other than valve design, affected shunt failure and to identify strategies that might be developed to reduce shunt failure.

METHODS

Ventricular size was measured at as many as six different intervals, using a modified Evans' ratio (with incorporation of the frontal and occipital dimensions), in 344 patients. Ventricular catheter location was defined as being in the frontal horn, occipital horn, body of the lateral ventricle, third ventricle, embedded in brain, or unknown. The ventricular catheter tip was described as surrounded by cerebrospinal fluid, touching brain, or surrounded by brain parenchyma within the ventricle (slit ventricle). Repeated measures analysis of variance for unbalanced data was used to analyze ventricular size. A Cox model (with incorporation of time-dependent covariates) was used to evaluate the contribution of age, etiology, shunt design, ventricular size, ventricular catheter location, and environment among the cases.

RESULTS

Ventricular volume decreased in an exponential fashion, forming a plateau at 14 months, and was similar for the three valves (P = 0.4). Frontal and occipital ventricular catheter tip locations were associated with a reduced risk of shunt failure (hazard ratios, 0.60 [P = 0.02] and 0.45 [P = 0.001], respectively). Ventricular catheter tips surrounded by cerebrospinal fluid or touching the brain were associated with a reduced risk of failure (hazard ratios, 0.21 and 0.33, respectively; P = 0.0001). Patients with myelomeningocele or large ventricles had increased risk of malfunction (hazard ratios, 1.78 [P = 0.006] and 2.33 [P = 0.03], respectively).

CONCLUSION

Decline of ventricular size over time is not affected by these different shunt valve designs. This suggests that the mechanical models of hydrocephalus on which the designs were based are inadequate. Ventricular catheter tip location and ventricular catheter environment are important. Techniques to accurately place ventricular catheters and new valve designs that effectively control ventricular size might reduce shunt malfunction.

Flexible endoneurosurgical therapy for aqueductal stenosis

We successfully managed 11 patients with aqueductal stenosis of adult or adolescent onset, with no mortality or significant morbidity, by using a flexible ventriculoscope to perform either a third ventriculostomy or an aqueductal plasty. A flexible fiberoptic ventriculoscope and its accessories were newly developed, and surgical techniques were improved. For all patients, cinemagnetic resonance imaging was a critical part of the preoperative and postoperative evaluation of cerebrospinal fluid flow in the third ventricle and in the aqueduct of Sylvius. All of the 11 patients showed patency to cerebrospinal fluid flow at the aqueduct of Sylvius and the floor of the third ventricle. Only one patient subsequently required a lumboperitoneal shunt. Flexible endoneurosurgical management is simple and safe and allows in situ observation and the ability to perform biopsies. Therefore, flexible endoneurosurgical third ventriculostomy and aqueductal plasty are now considered our treatment of choice for aqueductal stenosis in adults and adolescents.

Neuroendoscopic management of pineal region tumours

The management of pineal tumours remains controversial. During 1994 we treated four consecutive adults (16-44 yrs) harbouring a pineal tumour with a neuroendoscopic procedure. All of them presented with hydrocephalus. Pre-operative workup included cranial computerized tomography (CT), craniospinal magnetic resonance imaging (MRI) and serum levels of biological tumour markers. The endoscopic procedure consisted of a third ventriculostomy followed by biopsy with a flexible, steerable neuroendoscope. Histological diagnosis was achieved in three patients who no longer required a shunt device. Recorded complications were: bleeding during ventriculostomy that prevented us from obtaining a good sample for biopsy, short-term memory loss that cleared over a two-week period, and transient increase of pre-operative hemiparesis. Complications and morbidity are emphasized so as to be avoided with further technical experience. Neuroendoscopy affords a minimally invasive way of reaching three objectives by one-step surgery in the management of pineal region lesions: 1) CSF sample for analysis of tumour markers. 2) Treatment of hydrocephalus by third ventriculostomy. 3) Several biopsy specimens can be obtained identifying tumours which will require further open surgery or adjuvant radiation and/or chemotherapy.

Efficacy of the Ghajar Guide revisited: a prospective study

OBJECT

The goal of this study was to compare the freehand technique of catheter placement using external landmarks with the technique of using the Ghajar Guide for this procedure. The placement of a ventricular catheter can be a lifesaving procedure, and it is commonly performed by all neurosurgeons. Various methods have been described to cannulate the ventricular system, including the modified Friedman tunnel technique in which a soft polymeric tube is inserted through a burr hole. Paramore, et al., have noted that two thirds of noninfectious complications have been related to incorrect positioning of the catheter.

METHODS

Forty-nine consecutive patients were randomized between either freehand or Ghajar Guide-assisted catheter placement. The target was the foramen of Monro, and the course was through the anterior horn of the lateral ventricle approximately 10 cm above the nasion, 3 cm from the midline, to a depth of 5.5 cm from the inner table of the skull. In all cases, the number of passes was recorded for successful cannulation, and pre- and postplacement computerized tomography scans were obtained. Calculations were performed to determine the bicaudate index and the distance from the catheter tip to the target point.

CONCLUSIONS

Successful cannulation was achieved using either technique; however, the catheters placed using the Ghajar Guide were closer to the target.

Changes in human intracerebral temperature in response to different methods of brain cooling

The rectal, epidural, and intraventricular temperatures were continuously monitored in 10 seriously injured and unconscious patients admitted for neurosurgical intensive care. Different attempts were made to lower their brain temperatures. Isolated head cooling, whether with frozen liquid (Hypotherm Gel Kap; Flexoversal, Hilden, Germany) or a cooling helmet, had very limited effect. Nasopharyngeal cooling had no effect. During barbiturate coma, a considerable increase in brain temperature was observed. The administration of paracetamol was the single most effective method by which to lower brain temperature, at times by 2 degrees C and usually with a concomitant decrease in the temperature gradient between the rectum and the brain. However, in order to achieve a lasting reduction of brain temperature to 35 degrees C, we had to use a combination of head cooling and intensive whole-body cooling.

Long-term observations of intracranial pressure after severe head injury. The phenomenon of secondary rise of intracranial pressure

The long-term course of intracranial pressure (ICP) was studied in 53 patients from a group of 90 patients with severe head injury treated over a 3-year period. In 49 of these, ICP was significantly elevated during the observation period. The maximum in ICP was usually observed 24 to 96 hours posttrauma. A subgroup of patients developed a second rise of ICP. Such a course was observed in 15 (31%) of the 49 patients with intracranial hypertension. In these cases, ICP increased initially to 20 to 30 mm Hg but could be controlled. Thereafter, ICP was decreased again for at least 12 hours. The secondary ICP rise occurred 3 to 10 days after trauma. In six patients, intracranial hypertension became uncontrollable and eventually caused brain death. The outcome of patients with a secondary rise of ICP was worse when compared with that of patients without this complication. A cause of the secondary ICP rise could only be identified in some cases. Delayed traumatic intracerebral hemorrhage, traumatic vasospasm, hypoxia, and hyponatremia were diagnosed in seven cases. In seven other patients, the secondary ICP rise coincided with a pronounced leukocytosis, which was not associated with apparent infections. Because the occurrence and degree of a secondary rise of ICP after severe head injury are important factors affecting outcome, monitoring of ICP after severe head injury should be prolonged.

Laser-assisted neuroendoscopy using a neodymium-yttrium aluminum garnet or diode contact laser with pretreated fiber tips

OBJECT

Although lasers have proved to be valuable in neuroendoscopy, surgeons are still not comfortable using high-energy laser endoscopic probes in proximity to vital structures such as the basilar artery in third ventriculostomy. The authors have developed a special laser catheter for use in neuroendoscopy; the object of this paper is to present their experimental and clinical experiences using the catheter.

METHODS

This laser catheter is fitted with an atraumatic ball-shaped fiber tip that is pretreated with a layer of carbon particles. These carbon particles absorb approximately 90% of the energy emitted, which is very effectively converted into heat. As the heat is generated in this very thin layer of carbon coating, the temperature at the surface of the ball-shaped tip reaches ablative temperatures instantly at powers of only a few watts per second, which has enabled the authors to limit drastically the amount of laser light used and the length of exposure needed, thereby increasing safety even around critical structures.

CONCLUSIONS

The authors present experimental data and their clinical experience using these pretreated fiber tips with a neodymium-yttrium aluminum garnet contact laser or a diode contact laser in 49 patients (22 males and 27 females) and a variety of procedures: third ventriculocistemostomy (33 patients), cyst fenestration (nine patients), colloid cyst resection (six patients), and fenestration of the septum pellucidum (one patient). There was no instance of mortality or increased morbidity. To date, the procedure success rate is 100% and the overall outcome success rate is 86%. The authors conclude that pretreated atraumatic ball-shaped fiber tips now make laser application safe and effective in a variety of neuroendoscopic procedures. Because of their low power range (only several watts), compact diode lasers will be the energy source of first choice.

Monitoring of brain tissue pressure with a fiberoptic device

Continuous monitoring of brain tissue pressure can now be achieved with intracerebral placement of fiberoptic microtransducers. This study was undertaken to test the safety, accuracy, and reliability of this relatively new type of intracranial pressure (ICP) monitoring. Initially, the fiberoptic device was compared with a concurrently functioning intraventricular catheter in 18 patients. The results from the two methods corresponded closely over a wide range of pressures, and the correlation coefficient approached 1.0. Subsequently, this monitor was used for routine measurement of ICP in a series of almost 200 neurosurgical patients at risk of intracranial hypertension. The tracings showed good wave forms and consistent absolute values of ICP. No instances of hemorrhage, mechanical failure, or other complications were associated with this monitor, except one case of infection, which was not directly attributable to the device per se. When bilateral intraparenchymal pressures were recorded in patients with unilateral mass lesions, significant transitory pressure differentials between the ipsilateral and contralateral sides were documented. It is concluded that monitoring intraparenchymal pressure with the fiberoptic device offers safe and reliable ICP recordings for routine neurosurgical practice. In patients with unilateral masses, ICP should be measured in close proximity to the lesion.

Third ventriculostomy for hydrocephalus associated with spinal dysraphism: indications and contraindications

Twenty-five patients have undergone this procedure at our unit. These constitute 25% of our total experience with endoscopic third ventriculostomy (4). In the patients under 6 months of age, only one out of 11 patients has had a successful long-term result despite initial good fenestration of the floor of the third ventricle. These patients were selected on the basis of their adequate third ventricular size and a relatively slowly progressive hydrocephalus. Fourteen patients had a ventriculostomy performed instead of shunt revision. In 13 patients this has been a success long term. All of these patients had a Heyer-Schulte valve with antisiphon device installed for months, or more often, years, prior to the third ventriculestomy. We believe that the difference in these two groups is due to a very poor cerebrospinal fluid(CSF)-resorptive capability in patients immediately after back closure due to the prior venting of CSF into the amniotic sac. The absorptive capacity seems to improve with the passage of time in our patients who have had a shunt system that maintains a relatively normal intracranial pressure and thus contributes to the development of the patient's CSF-absorptive system.

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.

Impact of a standardized protocol and antibiotic-impregnated catheters on ventriculostomy infection rates in cerebrovascular patients

BACKGROUND

Ventriculostomy infections create significant morbidity. To reduce infection rates, a standardized evidence-based catheter insertion protocol was implemented. A prospective observational study analyzed the effects of this protocol alone and with antibiotic-impregnated ventriculostomy catheters.

OBJECTIVE

To compare infection rates after implementing a standardized protocol for ventriculostomy catheter insertion with and without the use of antibiotic-impregnated catheters.

METHODS

Between 2003 and 2008, 1961 ventriculostomies and infections were documented. A ventriculostomy infection was defined as 2 positive CSF cultures from ventriculostomy catheters with a concurrent increase in cerebrospinal fluid white blood cell count. A baseline (preprotocol) infection rate was established (period 1). Infection rates were monitored after adoption of the standardized protocol (period 2), institution of antibiotic-impregnated catheter A (period 3), discontinuation of antibiotic-impregnated catheter A (period 4), and institution of antibiotic-impregnated catheter B (period 5).

RESULTS

The baseline infection rate (period 1) was 6.7% (22/327 devices). Standardized protocol (period 2) implementation did not change the infection rate (8.2%; 23/281 devices). Introduction of catheter A (period 3) reduced infections to 1.0% (2/195 devices, P=.0005). Because of technical difficulties, this catheter was discontinued (period 4), resulting in an increase in infection rate (7.6%; 12/157 devices). Catheter B (period 5) significantly decreased infections to 0.9% (9 of 1001 devices, P=.0001). The Staphylococcus infection rate for periods 1, 2, and 4 was 6.1% (47/765) compared with 0.2% (1/577) during use of antibiotic-impregnated catheters (periods 3 and 5).

CONCLUSION

The use of antibiotic-impregnated catheters resulted in a significant reduction of ventriculostomy infections and is recommended in the adult neurosurgical population.