Accuracy of ultrasound-guided puncture of the ventricular system.

OBJECTS: Puncture of the ventricular system as one of the most frequently performed operative procedures in neurosurgery is usually done in a freehand way without guiding devices. The objective of this study is to examine whether ultrasonic guidance is able to heighten the accuracy of ventricular tapping. METHODS: Real-time imaging via a single burr hole approach is achieved by aid of a bajonet-like shaped transducer with a footprint of 8x8 mm only (EUP-NS32, Hitachi Medical Systems). The needle is advanced towards the frontal horn along a displayed guideline. 51 punctures in 48 patients were performed with ultrasonic guidance and compared to 85 punctures in 67 patients without a guiding device. CONCLUSION: The presented ultrasound method was not able to heighten the access rate of ventricular tapping, but it improved correct positioning of the catheter tip inside the frontal horn of the ventricular system significantly.

Gravitational shunt management of long-standing overt ventriculomegaly in adult (LOVA) hydrocephalus.

OBJECTIVES: Recently a new subtype of chronic hydrocephalus was described: long-standing overt ventriculomegaly in adults (LOVA). Experience to date has indicated that shunt therapy was contraindicated, due to over-drainage. Therefore we investigated whether this problem could be overcome using gravitational shunts. MATERIALS AND METHODS: Thirty macrocephalic adults (17-72 years of age), suffering from progressive hydrocephalus were managed with two different gravitational shunts. The post-operative observation period was 5-87 months. RESULTS: Only two patients developed hygromas, and only one of these required surgical shunt revision. Eighty-seven percent of patients had a long-lasting clinical improvement. Ventricular size was only slightly reduced in 29 patients. There was no correlation between reduction in ventricular size and clinical improvement. CONCLUSION: Contrary to clinical guidelines issued to date, we demonstrate that LOVA can be treated reliably with gravitational shunts, making them a genuine alternative to endoscopic third ventriculostomy (ETV).

[Complaints and findings at the iliac crest donor site following anterior cervical fusion]. / Postoperative Beschwerden und Befunde im Bereich der Spanentnahmestelle am Becken bei ventraler zervikaler Fusion.

A high rate of donor site complications has been described following bone graft harvesting at the anterior iliac crest for anterior cervical fusion. However, no prospective study exists dealing with this topic. The objectives of the study presented were to evaluate minor and major donor site complications following graft harvesting at the anterior iliac crest, to investigate postoperative changes at the donor site using computed tomography and ultrasound imaging and to judge the patients satisfaction. 67 patients were included in a clinical prospective study. All patients underwent anterior cervical discectomy and fusion using an autologous iliac crest graft. Clinical examination was performed three and ten days and two and three months after the operation. Computed tomography and ultrasound imaging of the donor site were performed 10 days after surgery. Complications were classified as "minor" and "major" complications. Minor complications were found in 62.7%. A significant decrease of minor complication rate was seen between the first and second examination after surgery. At the last follow-up, 80.5% of all patients were free from pain concerning the donor site. Haematomas and seromas were detected by ultrasound in 67.2% and donor site fractures in 6% using computed tomography. Major complications were seen in 11.9% of all patients. The current study revealed a high rate of minor complications and haematomas at the graft donor site. However, the majority of all patients is free of pain at the donor site three months after surgery and satisfied with the surgical result. Techniques without the need of bone grafting may help to avoid these complications and to ameliorate the initial postoperative status.

Concentration of rocuronium in cerebrospinal fluid of patients undergoing cerebral aneurysm clipping.

BACKGROUND: This study assessed the concentration of rocuronium in the cerebrospinal fluid (CSF) of patients undergoing cerebral aneurysm clipping, and investigated whether the mode of administration (single bolus vs continuous infusion) influenced the CSF concentration. METHODS: Twenty patients with subarachnoid haemorrhage were randomly allocated to receive a bolus dose (bolus group), or a bolus followed by a continuous infusion of rocuronium (infusion group) (n=10 for each group). Arterial blood and ventricular CSF were sampled 2 h after the rocuronium bolus. Samples were analysed by liquid chromatography electrospray ionization-tandem mass spectrometry. RESULTS: Rocuronium could be detected in all the CSF samples. The mean (range) CSF concentration was 2.2 (0.9-4.6) ng x ml(-1) in the bolus group and 12.4 (2.4-34.6) ng x ml(-1) in the infusion group; P<0.01. CONCLUSIONS: This study demonstrated that rocuronium, normally not considered to cross the blood-brain barrier, is regularly found in the CSF of patients undergoing cerebral clipping; continuous infusion of the drug led to higher plasma and CSF concentrations than after a single bolus dose.

Screw fixation to the posterior cortical shell does not influence peak torque and pullout in anterior cervical plating.

There is no consensus over whether screw fixation for anterior cervical plating should include the posterior cortical shell of the vertebral bodies or not. Thus, the purpose of this study was to investigate the function of the posterior cortical shell with respect to maximal screw torque and pullout force. Twenty-four fresh frozen human cervical vertebrae coming from six spinal segments C4-C7 were used. They were scanned for bone mineral density (BMD) and then assigned to two groups with comparable bone density and segmental distribution. The posterior longitudinal ligament was resected carefully and two parallel burr holes were drilled into each vertebral body. The posterior cortical shell was removed in one burr hole, using a 6-mm steel burr, producing a shallow excavation with a depth of approximately 2 mm. An ABC screw was inserted into each burr hole. The screw to be inserted into the hole with the posterior excavation was called "monocortical". In contrast, the contralateral screw was called "bicortical". Peak torque was measured in one group, while pullout force was analyzed using the specimens of the second group. Mean value and standard deviation were calculated for peak torque and pullout force with respect to the type of fixation. A paired t-test was used to determine the effect of fixation type on peak torque and pullout force. Pearson moment correlation coefficients were calculated to determine the effect of BMD on peak torque and pullout force with respect to whether the screw was "mono- or bicortical". A 95% level of significance was used for all tests. No significant differences for peak torque and pullout force could be found comparing monocortical and bicortical screw fixation. However, for both monocortical and bicortical screw fixation, a positive correlation was seen for peak torque versus BMD and for pullout force versus bone mineral density, respectively. The importance of the posterior cortical shell for screw pullout force and screw peak torque seems to be negligible. In constrast, BMD greatly influences both peak torque and pullout force for both types of fixation.

[Meningioangiomatosis with associated meningioma in a 4-year-old girl presenting with a focal seizure]. / Meningeoangiomatose mit assoziiertem Meningeom bei 4-jährigem Mädchen mit fokalem Krampfanfall.

Meningioangiomatosis is regarded as a rare, benign, hamartomatous malformation. Histopathologically, the lesion is characterized by circumscribed transcortical and leptomeningeal meningovascular proliferation with focal calcifications. It may be classified into cases with predominant cellular or vascular features and may occur in association with neurofibromatosis, mostly of type 2, but sporadic cases are more frequently reported. Sporadic cases often present initially with seizures and can be treated surgically. However, a certain percentage of patients will need ongoing anticonvulsive therapy. The lesions are seldom associated with an overlying meningioma. These are usually benign lesions that must be strictly separated from an invasive anaplastic meningioma, which would warrant an adjuvant therapy. We report on a 4-year-old girl who presented with spontaneous, predominantly cellular meningioangiomatosis with associated fibrous meningioma. Focal immunopositivity of the meningioangiomatosis for CD34 was helpful in ruling out an invasive meningioma.

Ultrasound-guided aspiration of brain abscesses through a single burr hole.

Surgical aspiration and/or drainage of brain abscesses is considered to be the first-line treatment for abscesses larger than 25 mm. This is ususally performed with the aid of CT-guided stereotaxy. A method of ultrasound guidance is presented that allows a single burr hole approach with real-time imaging of the whole procedure. A bayonet-like shaped ultrasound probe with tip dimension of 8 x 8 mm only (EUP-NS 32, Hitachi/Ecoscan) with frequencies of 3.5 and 5 MHz is used. After placement of a burr hole the target is identified by transdural insonation, a guideline is adjusted and a mounted puncture-adapter guides the cannula towards the lesion under real-time imaging control. Up to now 12 abscesses in 10 patients were treated. Visualization was always excellent. A second aspiration had to be performed twice. One abscess did not contain enough pus to be cured by aspiration and was removed by open surgery, another could not be tapped by the blunt cannula and was aspirated under stereotactic control using a sharp trocar. Outcome was excellent in 6 patients and fair in 2 patients but this was due to the pre-existing disease. Two patients admitted in deep coma died despite an emergency operation. The presented method has proven to be a very powerful guiding tool in the surgical treatment of brain abscesses through a single burr hole approach.

Vertex epidural hematoma with communicating bifrontal subgaleal hematomas treated by percutaneous needle aspiration.

The case of an 11-year-old boy is presented who suffered a bicycle accident with a parasagittal skull fracture, a small vertex epidural hematoma, frontal contusions and a frontal subgaleal hematoma. Enlargement of the vertex epidural hematoma was diagnosed after development of a slight paraparesis on day 11 with the aid of MRI. Three percutaneous needle aspirations of the subgaleal hematoma with a total of 59 ml being evacuated led to quick recovery and disappearance of the subgaleal as well as the vertex epidural hematoma. It is speculated that both hematomas communicated via the skull fracture thus making the evacuation of the epidural hematoma by subgaleal punctures possible.

Transcranial color-coded sonography of a vein of Galen arteriovenous malformation in an adult.

The case of an adult harboring a vein of Galen arteriovenous malformation (VGAM) is reported. Diagnosis was established by computed tomography (CT) and digital subtraction angiography and confirmed afterwards by transcranial color-coded sonography (TCCS). The patient's course after endovascular treatment was then consecutively monitored by TCCS until complete occlusion was achieved. The results of TCCS were validated by angiography, with which they showed good correlation. Thus, it can be concluded that TCCS may be a useful adjunct to CT and angiography to noninvasively monitor adults with VGAM.

Ultrasound-based navigation during intracranial burr hole procedures: experience in a series of 100 cases.

BACKGROUND: To establish a rational basis for intraoperative ultrasound guidance in neurosurgical procedures via a single burr hole approach based on the experience of one hundred cases. METHODS: The single burr hole approach is carried out using a bayonet-shaped ultrasound transducer with a tip dimension of 8 x 8 mm. The ultrasound probe with a mounted puncture adapter fits a standard burr hole and allows real-time imaging of the ongoing surgical steps. RESULTS: One hundred cases with five indications have been operated on so far: tapping of the ventricular system (46 patients), tapping of intracranial cysts (23 patients), biopsy of intracranial tumors (15 patients), evacuation of intracranial abscesses (9 patients), and evacuation of intracerebral hematomas (7 patients). Depending on their size, the ventricles could be clearly visualized in 34 of 46 patients. In the remaining patients the free margin of the falx served as orientation. Two ventricles could neither be visualized nor entered. Visualization and puncture of intracranial cysts were easy to achieve throughout, as was the case with abscesses. Tumor biopsy was unsuccessful in two patients harboring lymphomas at distances of more than 50 mm from probe to target. Intracerebral hematomas were easily visualized but, due to the presence of clots, aspiration was impossible in two patients. One patient with a giant glioblastoma died the day after the uneventful biopsy due to increased cerebral edema. No other complications occurred. CONCLUSIONS: The presented method of ultrasound-based neuronavigation is an easy-to-use, fast, and safe technique of real-time imaging for free-hand single burr hole procedures.

Identification of somatosensory pathways by focal-cooling-induced changes of somatosensory evoked potentials and EEG-activity--an experimental study.

OBJECT: Function-preserving neurosurgery requires methods to identify functionally important CNS-areas intraoperatively. We investigated whether a combination of focal cerebro-cortical cooling and monitoring of somatosensory evoked potentials (SEP) is suited for this task, i.e. whether it is able to outline structures belonging to the somatosensory pathway. METHODS: In 17 Wistar rats the somatosensory cortex was focally cooled by 20 degrees C below the initial tissue temperature for periods of five minutes. A cryoprobe with a tip diameter of 3 mm was used and tissue temperatures were measured below and at different distances to the cryoprobe. Tibial nerve evoked SEPs and EEG-spectra were recorded continuously. RESULTS: During cortical cooling the SEP-responses showed a marked delay and amplitude increase of the cortically generated components P13 and N18 and a small latency increase of the subcortically generated wave III. EEG-spectra were depressed mainly in the low frequency range. All cooling effects were reversible and in light- as well as electron-microscopic examinations no tissue damage was found. CONCLUSIONS: Focal cooling of the cortex induces easily recognizable and reversible changes of the bio-electrical activity without causing any histological damage. Therefore the method seems suitable for identifying eloquent areas. It can be expected that clinical application of the cooling technique in combination with intraoperative electrophysiological monitoring will be helpful to further lower the risk of neurosurgical operations. We propose that cooling mainly interferes with the synaptic transmission within the somatosensory cortex, because the observed amplitude increase can be explained by cold-induced depression of inhibitory cortical activity (disinhibition).

Acute hydrocephalus as a late complication of hemispherectomy.

Two cases of acute hydrocephalus 34 and 27 years after hemispherectomy are presented. Both were examined by intracranial pressure recordings and treated with shunting procedures. The recordings gave evidence of raised baseline values of intracranial pressure and showed pathological B-wave activity in over 80% of the recording time. The problem of free communication between the different compartments after hemispherectomy and different surgical approaches to solve the problem are discussed. Open surgery is not advocated.

Acute spinal intradural extramedullary hematoma: a nonsurgical approach for spinal cord decompression.

The authors present the case of a 60-year old man with a spontaneous spinal intradural hematoma in the thoracic and lumbar region, which was caused by anticoagulant therapy and led to a severe progressive transverse lesion. After substitution of coagulation factors, a small catheter was inserted into the subarachnoid space via a lumbar puncture. By alternating irrigation and suction removal of the blood clot, restoration of the cerebrospinal fluid passage was possible along with a marked improvement in the neurological deficits. At 8 months' follow-up, the patient had completely recovered from the severe paraparesis and bladder dysfunction.

Effects of high-frequency jet ventilation on intracranial pressure in experimental head-brain injury.

Based on experimental studies, ventilation with small volumes of gas and rates of up to 100-400/minute, high-frequency jet ventilation (HFJV), seems to present a true alternative to conventional intermittent positive pressure ventilation (IPPV), especially in patients with multiple organ damage. In order to determine the effects of high-frequency jet ventilation on intracranial pressure, we examined the effects of the HFJV in comparison to conventional ventilation in experimental balloon brain trauma. Ten young pigs were studied using continuous invasive hemodynamic, pulmonary, and intracranial pressure monitoring. There was no increase in brain pressure over normal ventilation. As a matter of fact, there was a temporary decrease of the intracranial pressure by about 5 mmHg, which returned to the initial pre-HFJV value after 5 minutes. In contrast to conventional ventilation, HFJV allows for tracheobronchial suctioning and interruption of ventilation without any noticeable increase of ICP.