Dirk Freudenstein

Spinal Subdural and Epidural Haematomas: Diagnostic and Therapeutic Aspects in Acute and Subacute Cases

Summary Background. The diagnosis of spontaneous spinal haematomas mainly depends on magnetic resonance imaging. This study evaluates the MRI characteristics of spinal epidural and subdural haematomas. The results were correlated with medical history, coagulation abnormalities and therapeutic outcome to provide guidelines for early diagnosis and treatment of spinal epidural and subdural hematomas. Summary of Background Data. Imaging signs of epidural and subdural haematomas have been reported before, however without special attention to the differential-diagnostic and therapeutic implications of haematoma localisation. Method. Seven patients (3 women, 4 men, age range 55–86 years) with acute progressive neurological deficits and without a history of severe trauma were studied. In all cases neurological examinations were performed after admission followed by MRI studies with T2 and T1 weighted images, before and after administration of contrast agent. Spinal angiography was performed twice to exclude a vascular malformation. All patients underwent open surgery. Findings. Acute and subacute hematomas were detected once in the cervical spine, in five cases in the thoracic region and once in the lumbar region. The hematomas had an epidural location in three cases and a subdural in four. In the thoracic region subdural haemorrhage was much more common than epidural hematomas. Subdural blood collections were mainly found ventral to the spinal cord. Epidural haemorrhage was always located dorsal to the spinal cord. The evaluation of the haematoma localisation may be difficult occasionally, but delineation of the dura is frequently possible in good quality MRI. The clue to the diagnosis of ventrally located subdural haemorrhage is the absence of the “curtain sign”, which is typical for epidural tumours. Interpretation. Spontaneous spinal hematomas are frequently located in the thoracic spine. Subdural spinal haemorrhage is more frequent than epidural. Epidural haemorrhage is frequently located dorsal to the spinal cord because of the tight fixation of the dura to the vertebral bodies.

Medical augmented reality based on commercial image guided surgery

Utilizing augmented reality for applications in medicine has been a topic of intense research for several years. A number of challenging tasks need to be addressed when designing a medical AR system. These include the import and management of medical datasets and preoperatively created planning data, the registration of the patient with respect to a global coordinate system, and accurate tracking of the camera used in the AR setup as well as the respective surgical instruments. Most research systems rely on specialized hardware or algorithms for realizing augmented reality in medicine. Such base technologies can be expensive or very time-consuming to implement. In this paper, we propose an alternative approach of building a surgical AR system by harnessing existing, commercially available equipment for image guided surgery (IGS). We describe the prototype of an augmented reality application, which receives all necessary information from a device for intraoperative navigation.

NOVEL ATP1A3 MUTATION IN A SPORADIC RDP PATIENT WITH MINIMAL BENEFIT FROM DEEP BRAIN STIMULATION

Rapid onset dystonia-parkinsonism (RDP) is a rare, autosomal dominantly inherited movement disorder, characterized by abrupt or subacute onset of both dystonic symptoms and parkinsonism with prominent bulbar involvement.1,2 Onset usually occurs in late adolescence or early adulthood and may be triggered by stresses such as physical exercise, extreme heat, or emotionally traumatic events. In one sporadic patient, bilateral deep brain stimulation (DBS) of the globus pallidus internus (GPi) failed to alleviate symptoms.3 Recently, six missense mutations in highly conserved regions of the ATP1A3 gene, encoding a Na+/K+-ATPase, have been identified.4 ### Case report. A 12-year-old boy experienced acute onset of severe dysphagia and dysarthria within hours after physical overexertion. Within weeks, severe generalized dystonia of all four limbs evolved, resulting in an inability to walk unassisted. Over the next 2 years, speech and swallowing improved considerably, but limb dystonia only slightly, so he was again able to walk independently. Extensive investigations including cranial MRI, DAT scan, CSF studies, EEG, and laboratory investigations …

Relevance of image fusion for target point determination in functional neurosurgery.

Summary.Summary. Background: For the treatment of medically refractory movement disorders such as Parkinsons disease, essential tremor and primary dystonia, deep brain stimulation (DBS) has become one of the main treatment options. The targets for implantation of the stimulation electrodes are various nuclei within the basal ganglia or the thalamic and subthalamic area. Accurate target localisation is of major importance for outcome and patient safety. The goal of this study was to evaluate the role of image fusion in the determination of target co-ordinates. Method: We conducted a retrospective study on 10 patients in whom 17 DBS electrodes had been implanted. Coordinates of the anterior and posterior commissures and of the DBS targets were compared on pre- and postoperative computerised tomography (CT) and fused CT/magnetic resonance scans. The targets as defined on the images were further compared with the targets derived intra-operatively with microelectrode recordings (MER) and macrostimulation. Findings: The achievable mean target accuracy was of the order of the diameter of the DBS electrode and of the accuracy of the image fusion algorithm, i.e. about 1 mm. However, the maximal differences were between 1.8 mm and 3.2 mm. Interpretation: Image fusion is a helpful tool for accurate determination of target point co-ordinates in DBS. In combination with intraoperative, electrophysiological recordings and stimulation which are still considered to be the most reliable localisation methods, image fusion may help to discern the anatomical and functional three-dimensionality of the target nuclei. Image fusion may reduce the number of trajectories needed for intraoperative electrophysiological determination of the optimal electrode localisation and thus lower the risk of complications.

Sustained improvement of obsessive–compulsive disorder by deep brain stimulation in a woman with residual schizophrenia

Co-occurrence of obsessive–compulsive disorder (OCD) and schizophrenia is not rare (Eisen et al., 1997). Given that the obsessional content is not related to psychotic subject matter, both disorders can be regarded as delimitable diagnostic entities (Bottas et al., 2005). Recently, a number of case reports and small case series have demonstrated that deep brain stimulation (DBS) targeting the fronto-striato-thalamic circuit can have beneficial effects on OCD (Abelson et al., 2005; Greenberg et al., 2006; Sturm et al., 2003). DBS treatment of patients with current or past psychotic disorders has not yet been reported. Here, we present a comprehensive clinical evaluation of a woman with intractable OCD and residual symptoms of schizophrenia that were treated with unilateral DBS of the right nucleus accumbens (NAc), including neuropsychological long-term follow-up, neurophysiological measurements and functional brain imaging. This 51-yr-old right-handed woman suffered from a severely disabling, chronic and intractable form of OCD with excessive hand washing, cleaning, rearrangement of objects and compulsory praying [Yale–Brown Obsessive Compulsive Scale (YBOCS) score 32/40, 1 month prior to treatment]. Psychosocial functioning as measured by the GAF (Global Assessment of Functioning) scale was severely impaired (31/100). The symptoms started during childhood and accumulated during her early twenties. Obsession consisted of preoccupation with thoughts about guilt and purgation. Later in the course of the disease, psychotic symptoms (delusions, hallucinations, disorganized behaviour) meeting DSM-IV criteria for schizophrenia occurred transiently. The remaining presence of a few odd beliefs, minor paranoid ideation and disorganized behaviour in an attenuated form that were unrelated to the obsessions and compulsions led to the diagnosis of residual schizophrenia according to DSM-IV using SCID (Structured Clinical …

Specific intensity imaging for glioblastoma and neural cell cultures with 5-aminolevulinic acid-derived protoporphyrin IX

The fluorescence of protophorphyrin IX (PpIX) synthesized after incubation with 5-aminolevulinic acid (5-Ala) is used for the intraoperative visualisation of glioma cells in vivo. Such fluorescence may also be useful for the photodynamic therapy (PTD) of gliomas. A significant difference of fluorescence intensity in tumor cells compared to neurons is required for this application. To explore this, eight human glioma cell lines (LN-18, LN-428, U87MG, U373MG, D247MG, U251MG, LN-308, T98G) were compared with human astrocytes (SV-FHAS) and rat neurons after incubation for different periods of timein vitro with 5-Ala (1mg/ml). Fluorescence intensity profiles were measured by a digital camera comparing glioma cell lines with control cells. All glioma cell lines could be discriminated from neural cells by their intensity of fluorescence by post-hoc tests for pairwise comparisons using Tukey’s honestly significant difference test, at the global significance level of 5%. The glioma cell lines showed significant variation in this possibly limiting clinical use of fluorescence as a guide for resection.

Recurrence of a Cerebral Arteriovenous Malformation after Surgical Excision

Complete resection of a cerebral arteriovenous malformation (AVM) should eliminate the future risk of an associated intracranial bleeding. Because total removal of an AVM may be difficult to assess at the time of surgery, postoperative angiography has become the accepted standard for documenting that complete removal has been achieved. However, even angiographically confirmed excision of an AVM does not completely exclude the possibility of rebleeding. Regrowth of an AVM with subsequent haemorrhage has been documented in children and is attributed to forces acting on the immature vasculature. The authors report the case of a 21-year-old man whose AVM recurred 5 years after angiographically proven complete excision. According to the presented case, the authors emphasise that, even in adults, angiographic documentation of total removal does not always eliminate the risk of reformation of an AVM.

Effective thalamic deep brain stimulation for neuropathic tremor in a patient with severe demyelinating neuropathy

Postural and action tremor in peripheral neuropathy is characteristic of Roussy–Levy syndrome. A patient with a severe demyelinating neuropathy and disabling neuropathic tremor successfully treated by deep brain stimulation (DBS) is reported. Disease onset was at age 63 years with sensory symptoms and slight action tremor. Within the following 9 years a severe, drug resistant, postural and action tremor developed rendering the patient unable to feed himself. At age 72 years the patient was treated by bilateral DBS of the ventral intermediate thalamic nucleus, with a useful 30% reduction in tremor. The clinical benefit of the stimulation remained stable over a 1 year postoperative observation period.

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.

Early activation of the primary somatosensory cortex without conscious awareness of somatosensory stimuli in tumor patients.

The primary sensory cortex has usually been regarded as a necessary step in the information processing stream leading to conscious awareness. Recently, it has been proposed that that higher order associative areas rather than the primary sensory areas are the neural basis of conscious perception. In two patients with tumors near the central region we recorded magnetic somatosensory evoked fields. Magnetic source imaging revealed early (40 ms) neural activation in primary somatosensory cortex and absence of later (>60 ms) neural activation in the primary and associative areas in these patients. None of the patients showed conscious awareness of somatosensory stimuli applied to the corresponding body site although the first component of the evoked field was within normal limits. The time course of the magnetic responses and additional evidence on intensity ratings of somatosensory stimuli suggest that early activity in the primary somatosensory cortex is not sufficient for conscious experience to emerge.