Biomedical subjects

C A F Tulleken

Publications and source records attributed to C A F Tulleken.

11 recordsLinked to original sources

PubMed2006

Neuronavigation and surgery of intracerebral tumours.

Approximately four decades after the successful clinical introduction of framebased stereotactic neurosurgery by Spiegel and Wycis, frameless stereotaxy emerged to enable more elaborate image guidance in open neurosurgical procedures. Frameless stereotaxy, or neuronavigation, relies on one of several different localizing techniques to determine the position of an operative instrument relative to the surgical field, without the need for a coordinate frame rigidly fixed to the patients' skull. Currently, most systems are based on the optical triangulation of infrared light sources fixed to the surgical instrument. In its essence, a navigation system is a three-dimensional digitiser that correlates its measurements to a reference data set, i.e. a preoperatively acquired CT or MRI image stack. This correlation is achieved through a patient-to-image registration procedure resulting in a mathematical transformation matrix mapping each position in 'world space' onto 'image space'. Thus, throughout the remainder of the surgical procedure, the position of the surgical instrument can be demonstrated on a computer screen, relative to the CT or MRI images. Though neuronavigation has become a routinely used addition to the neurosurgical armamentarium, its impact on surgical results has not yet been examined sufficiently. Therefore, the surgeon is left to decide on a case-by-case basis whether to perform surgery with or without neuronavigation. Future challenges lie in improvement of the interface between the surgeon and the neuronavigator and in reducing the brainshift error, i.e. inaccuracy introduced by changes in tissue positions after image acquisition.

Brain Neoplasms↗

PubMed2006

[The current MRSA policy in the Netherlands is doing more harm than good].

The current policy concerning methicillin-resistant Staphylococcus aureus (MRSA) in hospitals needs to be altered because there is no reliable proof that the isolation policy that is currently in force actually leads to any reduction in the prevalence of MRSA. Conversely, it has been proved that these isolation measures lead to poorer patient care, sometimes resulting in death.

Cross Infection↗

PubMed2005

Early posttraumatic subarachnoid hemorrhage due to dissecting aneurysms in three children.

Subarachnoid hemorrhage (SAH) due to a ruptured saccular aneurysm is uncommon in children. Pediatric traumatic aneurysms have been reported relatively frequently, tending to bleed after an interval of weeks after head injury. The authors describe three children with acute SAH after head injury caused by intracranial dissecting aneurysms. When head trauma in children is complicated by SAH in basal cisterns, dissecting aneurysms should be considered and treated, because rebleeding may occur.

Acute Disease↗

PubMed2005

Timing of aneurysm surgery in subarachnoid haemorrhage--an observational study in The Netherlands.

BACKGROUND: There is still lack of evidence on the optimal timing of surgery in patients with aneurysmal subarachnoid haemorrhage. Only one randomised clinical trial has been done, which showed no difference between early and late surgery. Other studies were observational in nature and most had methodological drawbacks that preclude clinically meaningful conclusions. We performed a retrospective observational study on the timing of aneurysm surgery in The Netherlands over a two-year period. METHOD: In eight hospitals we identified 1,500 patients with an aneurysmal subarachnoid haemorrhage. They were subjected to predefined inclusion criteria. We included all patients who were admitted and were conscious at any one time between admission and the end of the third day after the haemorrhage. We categorised the clinical condition on admission according the World Federation of Neurological Surgeons (WFNS) grading scale. Early aneurysm surgery was defined as operation performed within three days after onset of subarachnoid haemorrhage; intermediate surgery as performed on days four to seven, and late surgery as performed after day seven. Outcome was classified as the proportion of patients with poor outcome (death or dependent) two to four months after onset of subarachnoid haemorrhage. We calculated crude odds ratios with late surgery as reference. We distinguished between management results (reconstructed intention to treat analysis) and surgical results (on treatment analysis). The results were adjusted for the major prognosticators for outcome after subarachnoid haemorrhage. FINDINGS: We included 411 patients. There were 276 patients in the early surgery group, 36 in the intermediate surgery group and 99 in the late surgery group. On admission 78% were in good neurological condition (WFNS I-III). MANAGEMENT RESULTS: Overall, 93 patients (34%) operated on early had a poor outcome, 13 (36%) of those with intermediate surgery and 37 (37%) in the late surgery group had a poor outcome. For patients in good clinical condition on admission and planned for early surgery the adjusted odds ratio (OR) was 1.3 (95% CI 0.5 to 3.0). The adjusted OR for patients admitted in poor neurologicalcondition (WFNS IV-V) and planned for early surgery was 0.1 (95% CI 0.0 to 0.6). SURGICAL RESULTS: For patients in good clinical condition on admission who underwent early operation the adjusted OR was 1.1 (95% CI 0.4 to 3.2); it was 0.2 (95% CI 0.0 to 0.9) for patients admitted in poor clinical condition. CONCLUSIONS: In this observational study we found no significant difference in outcome between early and late operation for patients in good clinical condition on admission. For patients in poor clinical condition on admission outcome was significantly better after early surgery. The optimal timing of surgery is not yet settled. Ideally, evidence on this issue should come from a randomised clinical trial. However, such a trial or even a prospective study are unlikely to be ever performed because of the rapid development of endovascular coiling.

Adolescent↗

PubMed2005

Prediction of independence and intelligence at birth in meningomyelocele.

OBJECTIVE: The aim of this research is to compute a prediction of the future intelligence of every neonate with a meningomyelocele (MMC) on the day of birth to inform the parents. Earlier research revealed that the variables ventricle size, open arch above vertebra lumbar 3, a very small or a very large head can be attended by an IQ below 85 points: the turning point between dependence and independence. METHODS: Until now no research has been done combining the values of influencing variables in one equation. Our study used the equation of multiple longitudinal linear regression. For reference, data from the files of 148 neonates born in the years 1960-1980 were compared with those of Dutch children sampled by Verger. The working hypothesis that the IQ level is directly related to congenital deformities of the nervous system needs to be tested. As standard the values of variables at birth, the head circumference and length, the size of the ventricles and the highest open vertebral arch, are to be used. RESULTS: The Wisc-R of the MMC cohort had a mean of 84 points and 55% had an IQ above 85. The correlation computation of the values of all available variables with the values of the measured Wisc-R revealed the significance of the neuroanatomical variables, size of ventricle and level of the highest open vertebral arch and for the anthropomorphic variables Length and Length/Circumference. To establish the relationship between the Wisc-R value and the values of the significant variables an equation with the multiple linear regression method was used. The measured IQ is made dependent on the significant variables size of ventricle, level of highest open arch and quotient Length by Circumference. This equation produces a value called predicted IQ. The predicted IQ was 92%, the same or nearly the same as the measured Wisc-R IQ. CONCLUSION: This conformity of the measured IQ and the predicted IQ proves the possibility of using these birth data for prediction.

Adult↗

PubMed2005

Magnetic resonance imaging in experimental subarachnoid haemorrhage.

BACKGROUND: We developed an MRI protocol to measure cerebrovascular diameter and blood flow velocity, and if we could detect cerebrovascular alterations after SAH and their impact on cerebral ischaemia. METHOD: SAH was induced in 15 Wistar rats by means of the endovascular filament method; 6 other rats served as control. MRI measurements were performed on a 4.7T NMR spectrometer 1 and 48 hours after SAH and 9 days thereafter. Diffusion-weighted and T2-weighted images were acquired to detect cerebral ischaemia. The arterial spin labelling method was used to measure CBF. MR angiography was used to measure vessel diameter and blood flow velocity, from which the arterial blood flow was calculated. FINDINGS: The ischemic lesion volume increased between 1 and 48 hours after SAH from 0.039 to 0.26 ml (P = 0.003). CBF decreased from 53.6 to 39.1 ml/100 g/min. The vessel diameter had narrowed, the blood flow velocity diminished as did the arterial blood flow in most vessels, but only the vasoconstriction in the right proximal ICA reached significance (0.49 mm to 0.43 mm, P = 0.016). Baseline values were restored at day 9. CONCLUSIONS: We showed that it is feasible to detect alterations of in-vivo vessel diameter and blood flow velocities and their consequences for brain damage after experimental SAH in the rat. The growth of the infarct volume between day 0 and 2 after SAH and the parallel vasoconstriction suggest that delayed cerebral ischaemia after SAH occurs in rats and that this may be caused by vasoconstriction.

Animals↗

PubMed2005

The impact of auditory feedback on neuronavigation.

OBJECT: We aimed to develop an auditory feedback system to be used in addition to regular neuronavigation, in an attempt to improve the usefulness of the information offered by neuronavigation systems. INSTRUMENTATION: Using a serial connection, instrument co-ordinates determined by a commercially available neuronavigation system were transferred to a laptop computer. Based on preoperative segmentation of the images, the software on the laptop computer produced an audible signal whenever the instrument moved into an area the surgeon wanted to avoid. METHODS: To evaluate the impact of our setup on volumetric resections, phantom experiments were conducted. CT scans were acquired from eight blocks of floral foam. In each of these scans, a target-volume was segmented. This target-volume was subsequently resected using either regular neuronavigation or neuronavigation extended with auditory feedback. A 'postoperative' CT scan was used to compare the resection cavity to the preoperatively planned target-volume. FINDINGS: The resemblance between the resection cavity and the target-volume was greater each time auditory feedback had been used. This corresponded with more complete removal of the target-volume. However, it also corresponded with the removal of more non-target 'tissue' in two out of four cases. CONCLUSIONS: The usefulness of auditory feedback was made plausible and the use of a new type of navigation phantom was illustrated. Based on these results, we recommend incorporation of auditory feedback in commercially available neuronavigation systems, especially since this is relatively inexpensive.

Acoustic Stimulation↗

PubMed2004

The ELANA technique: constructing a high flow bypass using a non-occlusive anastomosis on the ICA and a conventional anastomosis on the SCA in the treatment of a fusiform giant basilar trunk aneurysm.

A patient with a partially thrombosed fusiform giant basilar trunk aneurysm presented with devastating headache and symptoms of progressive brain stem compression. Having an aneurysm inaccessible for endovascular treatment, and after failing a vertebral artery balloon occlusion test, he was offered bypass surgery in order to exclude the aneurysm from the cerebral circulation and relieve his symptoms. A connection between the intracranial internal carotid artery and the superior cerebellar artery was created whereupon the basilar artery was ligated just distally to the aneurysm. The proximal anastomosis on the internal carotid artery was made using the excimer laser-assisted non-occlusive anastomosis (ELANA) technique, while a conventional end-to-side anastomosis was used for the distal anastomosis on the superior cerebellar artery. Intra-operative flowmetry showed a flow through the bypass of 40 ml/min after ligation of the basilar artery. An angiogram 24 hours later showed normal filling of the bypass and the vessels supplied by it, but also disclosed a subtotal occlusion of the proximal ipsilateral middle cerebral artery with delayed filling distally. The patient, who had a known thrombogenic coagulopathy, died the following day. Autopsy showed no signs of ischemia in the territories supplied by the bypass, but a thrombus in the proximal middle cerebral artery and massive acute hemorrhagic infarction with swelling in its territory and uncal herniation. Multiple fresh thrombi were found in the lungs. The ELANA anastomosis showed re-endothelialisation without thrombus formation on the inside.

Adult↗

PubMed2003

Cerebral revascularization.

During the last 10 years, there has been a revival of interest in cerebral revascularization procedures. Not only have significant progressions in surgical techniques been published, the use of more advanced diagnostic methods has led to a widening of the indications for cerebral bypass surgery. The purpose of this review is to outline the current techniques for extracranial-to-intracranial (EC/IC) and intracranial-to-intracranial (IC/IC) bypass surgery, as well as to identify the current indications for revascularization procedures based on the available literature. The excimer laser-assisted non-occlusive anastomosis (ELANA) technique is described in more detail because we think that this technique almost completely eliminates the risk of cerebral ischemia due to the temporary vessel occlusion which is currently used in conventional anastomosis techniques.

Animals↗

PubMed2003

Clinical evaluation of stereotactic brain biopsies with an MKM-mounted instrument holder.

OBJECT: The aim of this study was to assess the clinical usefulness and accuracy of robot-assisted frameless stereotactic brain biopsies with a recently introduced MKM-mounted instrument holder. METHODS: Twenty-three patients with intracranial lesions participated in this study. Depending on the size of the intracranial lesion, fiducials for image-to-patient co-ordinate transformation consisted either of bone screws or adhesive markers. Shortly after surgery, postoperative MRI-imaging was performed to demonstrate the location of the biopsy site. These images were compared with the preoperative images to assess the biopsy localisation error. RESULTS: Postoperative biopsy sites could be demonstrated in six patients with bone screws and in 14 with adhesive markers. These two subgroups yielded average biopsy localisation errors of 3.3 mm (SD 1.7 mm) and 4.5 mm (SD 2.0 mm) respectively. This difference was not statistically significant. One biopsy was located in a liquefied haematoma. All others yielded pathological tissue. There were two postoperative haemorrhages, of which only one was temporarily symptomatic. There was no mortality in the first 30 days after surgery. CONCLUSIONS: Robot-assisted frameless point-stereotactic techniques represent an alternative to frame-based techniques for the performance of stereotactic biopsies.

Adult↗

PubMed2002

Endovascular coiling versus neurosurgical clipping in patients with a ruptured basilar tip aneurysm.

OBJECTIVES: To compare endovascular coiling with neurosurgical clipping of ruptured basilar bifurcation aneurysms. METHODS: Patient and aneurysm characteristics, procedural complications, and clinical and anatomical results were compared retrospectively in 44 coiled patients and 44 patients treated by clipping. The odds ratios for poor outcome (Glasgow outcome scale 1, 2, 3) adjusted for age, clinical condition, and aneurysm size were assessed by logistic regression analysis. RESULTS: In the endovascular group, five patients (11%) had a poor outcome v 13 (30%) in the surgical group; the adjusted odds ratio for poor outcome after coiling v clipping was 0.28 (95% confidence interval, 0.08 to 0.99). Procedural complications were more common in the surgical group. Optimal or suboptimal occlusion of the aneurysm immediately after coiling was achieved in 41 patients (93%). Clipping was successful in 40 patients (91%). CONCLUSIONS: The results suggest that embolisation with coils is the preferred treatment for patients with ruptured basilar bifurcation aneurysms.

Aneurysm, Ruptured↗