V. van Velthoven

Intraoperative ultrasound (US) imaging. Comparison of pathomorphological findings in US and CT.

SummaryExperience with the use of intraoperative ultrasound (US) imaging in over 300 patients are presented in this paper and discussed with special reference to various pathomorphologies as well as their identifiability within the brain/intracranium. In 201 of these patients, the pathomorphological peculiarities in US could be compared with preoperative CT findings.As a general result, all investigated lesions could be identified during intraoperative US investigations with the exception of small aneurysms. Most of the lesions gave at least partly higher echosignals than normal brain tissue, except arachnoid cysts. Size and shape of lesions were comparable in US and CT with the exception of some gliomas; in the latter group, the diffuse image in US was more akin to the situation likely to be found by the surgeon during operation, wheras CT used to give a misleading picture of a more or less clearly delineated tumour. US allowed more accurate differentiation between intratumoural necrosis and cysts than CT: the latter was misleading in many instances.At the present state of development, real time US imaging does not allow a histopathological diagnosis. The ease of handling and the high quality of morphological imaging, however, warrant a number of practical applications in daily neurosurgical practice.

Practical application of intraoperative ultrasound imaging

SummaryIntraoperative real-time ultrasound imaging (US) was used in over 500 patients to investigate which of the previously considered applications are of practical use in everyday neurosurgery.During all intraoperative applications for a wide variety of pathological conditions, small deep-seated as well as subcortically located lesions were detected with accuracy; in many instances they could be approached through smaller surgical exposures. US guidance was accurate in 209 cases for the stereotactic introduction of needles or endoscopes into various lesions: thus burrhole evacuation was performed on 148 intracerebral haematomas; in 16 patients endoscopic biopsy and resection of ventricular tumours was performed as well as biopsies of 39 hemispheric brain tumours and aspiration of a brain abscess in 6 instances. Seventy six gliomas were investigated by US imaging; the frequently unclear boundary between tumour and surrounding oedema was not better visualized than with CT or MRI. Moreover, US imaging for the detection of residual tumour towards the end of operation was unreliable. Postoperative imaging through burrholes or other cranial defects was mostly of unacceptably low quality for therapeutic decision making.

Intraoperative Ultrasound Imaging: Comparison of Pathomorphological Findings in US Versus CT, MRI and Intraoperative Findings

Since 1987, Ultrasound (US) is performed routinely as real time navigation system in our neurosurgical practice. In 374 cases with different pathologies the preoperative CT and MRI images were compared with the intraoperative US images and the operative findings. In all instances, the lesion could be localized and described in detail. US findings correlated with the findings an CT/MRI, concerning size and shape of lesions. US allowed the differentiation of more structural details within tissue compartments. The demarcation of gliomas was not as well defined in US as compared to CT/ MRI, which correlated with the intraoperative situation. As for CT/ MRI imaging, a correlation between US findings and histopathology of the lesion was not possible. In our opinion, intraoperative US imaging is an excellent tool for localization of cerebral and medullar lesions and for detailed description of their interior. This indicates a widespread applicability of this method in neurosurgery as an anatomical link between preoperative imaging and the reality of the operative field.

Evaluation of MR imaging, digital subtraction cisternography, and CT cisternography in diagnosing CSF fistula

SummaryExact preoperative localization of the dural defect is an essential requirement for successful surgery of CSF fistula. Eighteen digital subtraction cisternography (DSC) results reported here were performed upon 16 patients with CSF rhinorrhea and 1 patient with CSF otorrhea. The exact site of the dural lesion could be proved in 9 out of 11 cases with active CSF leakage. In 4 cases the fistula was located in the cribriform plate, whereas it was found in the planum sphenoidale and the middle cranial fossa in 2 and 3 cases respectively. The frontal basal cisterns could not be filled sufficiently with the contrast agent due to haematoma and a prefixed chiasm accompanied by arachnoid adhesions in two cases. DSC performed during the non-drip period (3 cases) and in patients suspected to have a CSF rhinorrhea (3 cases) did not reveal the site of leakage.The investigation was followed by CT cisternography which allowed delineation of the lesion in the coronal view. In addition. MR with heavily T 2-weighted images (modification of the rapid acquisition with relaxation enhancement imaging) was performed upon 6 cases out of which the CSF fistula could be demarcated clearly in 4 patients, three with a traumatic CSF leakage and the other with an encephalomeningocele.Surgery performed successfully in 9 cases confirmed the predicted site of dural dehiscence.Being a dynamic investigation making the actual site of the CSF fistula visible, DSC is recommended in addition to CT cisternography which continues to be the most sensitive method for diagnosing dural and bony defects. It is suggested that heavily T 2-weighted MR images are useful in detecting the fistula in severe CSF rhinorrhea.

Intraoperative Ultrasound Imaging: Practical Applicability as a Real-Time Navigation System

Experience with the use of Intaoperative Ultrasound (US) imaging as real time navigation system in neurosurgery is presented and discussed. Since 1987 we have performed US routinely in a wide variety of intracerebral and intramedullar pathologies. In this analysis we define useful intraoperative applications. Accurate definition of deep-seated lesions and their delineation from surrounding anatomical structures is possible with an US frequency of 5 MHz. Small subcortically located lesions can clearly be visualized with a high frequency probe. Differentiation between solid tumor, cyst and necrosis can be delineated. Identification of residual tumor is difficult. Dural sinuses and eventual invading tumor can be visualized by a 10 MHz probe. US guidance can be helpful for puncturing with a catheter, needle or endoscope. Postoperative percutaneous US imaging through a burr hole did not prove to be useful. The intraoperative use of US imaging is a reliable method for determining the size, shape and localization of lesions. It can be used as a practicable, cost effective and timesaving real time navigation system.

Diagnosis of brain death. Transcranial Doppler sonography as an additional method

SummaryEver since transplant surgery became a common procedure, the early diagnosis of irreversible cessation of cerebral function has become an important need.We made a comparative study of EEG, angiography and transcranial Doppler imaging in patients who fulfilled the clinical criteria for brain death. The imaging was performed with a 2 MHz pulsed Doppler system with a unique transcranial probe (EME, type TC2-64B).Intracranial reverberating flow patterns with counterbalancing forward and backward components of the blood column indicate flow arrest.Transcranial Doppler Sonography was found to be a practical, non invasive, early and reliable method for the diagnosis of arrest of the cerebral circulation.

Benefits and limitations of image guidance in the surgical treatment of intracranial dural arteriovenous fistulas.

SummaryBackground. Despite major advances in endovascular embolization techniques, microsurgical resection remains a reliable and effective treatment modality for dural arteriovenous fistulas (DAVF). However, intraoperative detection of these lesions and identification of feeding arteries and draining veins can be challenging. In a series of 6 patients who were not candidates for definitive treatment by endovascular embolization we evaluated the benefits and limitations of computer-assisted image guidance for surgical ablation of DAVF. Methods. Of the 6 patients, 5 presented with haemorrhage and one with seizures. Diagnosis of DAVF was made by conventional angiography and dynamic contrast enhanced MR angiography (CE-MRA). All patients were surgically treated with the assistance of a 3D high resolution T1-weighted MR data set and time-of-flight MR angiography (MRA) obtained for neuronavigation. Registration was based on cranial fiducials and image-guided surgery was performed with the navigation system. Findings. Four of the 6 patients suffered from DAVF draining into the superior sagittal sinus, one fistula drained into paracavernous veins adjacent to the superior petrosal sinus and one patient had a pial fistula draining in the straight sinus. DAVF diagnosed with conventional angiography could be located on CE-MRA and MRA prior to surgery. MRI and MRA images were combined on the neuronavigation workstation and DAVF were located intraoperatively by using a tracking device. In 4 out of 6 cases neuronavigation was used for direct intraoperative identification of DAVF. Brain shift prevented direct tracking of pathological vessels in the other 2 cases, where navigation could only be used to assist craniotomy. Microsurgical dissection and coagulation of the fistulas led to complete cure in all patients as confirmed by angiography. Conclusions. Neuronavigation may be used as an additional tool for microsurgical treatment of DAVF. However, in this small series of 6 cases, surgical procedures have not been substantially altered by the use of the neuronavigation system. Image guidance has been beneficial for the location of small, superficially located DAVF, whereas a navigated approach to deep-seated lesions was less accurate due to the familiar problem of brain shift and brain retraction during surgery.

Subarachnoid haemorrhage due to cervical spinal cord haemangioblastomas in a patient with von Hippel-Lindau disease

Summary¶A case is presented with severe infra- and supratentorial subarachnoid haemorrhage (SAH) caused by intramedullary haemangioblastomas of the cervical spinal cord. The patient initially had a typical SAH symptomatology without neurological deficit. The cerebral angiogram was nondiagnostic. After admission the patient developed slightly progressive right sensorimotor paresis. Angiography of the cervical spine and MRI delineated three intramedullary haemangioblastomas. Retrospectively the diagnosis of von Hippel-Lindau (VHL) disease was made by multiple haemangioblastomas and a positive family history. The three lesions were surgically completely removed.

Late bacterial granuloma at an intrathecal drug delivery catheter

SummaryIn the case reported, neurological complaints were pain and dysaesthesiae in the lower back and thigh, as well as paresis of the ileopsoas muscle. MRI of the lumbar spine showed an intradural-extramedullary mass at the level of L1 homogeneously enhancing with gadolinium. This mass was situated at the tip of an intrathecal catheter implanted 11 years before for a morphine trial infusion as therapy for phantom pain after amputation of the right arm. Now, removal of the catheter was performed. Cultures of lumbar CSF and the catheter tip demonstrated coagulase negative staphylococcus. Antibiotic medication with cephalosporines was given for 6 weeks. After removal of the catheter, the patient was free of pain and he progressively regained full neurological function. Although most catheter-associated granulomas reported so far were sterile in nature, bacterial infection should still be considered even years after catheter placement.

Comparative study of two customary cerebrospinal fluid shunting systems in early childhood hydrocephalus

SummaryThe validity of clinical studies on shunt-treated hydrocephalic patients is often hindered by inhomogeneity of the patient population examined, technical devices used, or by other specific factors. In an effort to introduce a homogeneous clinical study on hydrocephalic patients 66 hydrocephalic newborns and infants have been treated exclusively with CORDIS Orbis-Sigma Valve (OSV) System (CORDIS Corporation, Miami, USA) in 1990–1995. The results are compared with an equivalent group of 53 children treated with CODMAN Holter Valve (HV) System (CODMAN Inc., Randolph, USA) during a similar 5-year-period (e.g., 1986–1991). Searching for different reasons of shunt insufficiency in both groups demonstrates a more than double risk of shunt complication for ventriculo-atrial HV treated patients (VA-HV) in comparison with those treated ventriculo-peritoneally with OSV System (VP-OSV): 4.22 versus 1.98 mean surgical procedures per person. The different revision and survival rates are discussed and specific problems are mentioned.