Intraoperative clinical testing overestimates the therapeutic window of the permanent DBS electrode in the subthalamic nucleus.

BACKGROUND: Intraoperative test stimulation is established to optimize target localization in STN DBS, but requires a time-consuming awake surgery in off-medication state. The aim of this study was to compare the thresholds of stimulation-induced effects of test stimulation and the permanent electrode. METHODS: Fifty-nine PD patients receiving bilateral STN DBS were clinically examined with stepwise increasing monopolar stimulation during surgery and DBS programming at matched stimulation depths. Thresholds of therapeutic and side effects were obtained from standardized examination protocols. RESULTS: Postoperative stimulation via the permanent electrode caused side effects at a significantly lower threshold than predicted during intraoperative test stimulation (P < 0.001); whereas sufficient therapeutic effects were achieved at significantly higher thresholds (P < 0.001). CONCLUSIONS: Intraoperative testing may lead to an overestimation of the therapeutic window. The two different electrodes lead to distinct spreading of the electric field in the STN and surrounding tissues that causes different volume of tissue activated (VTA). Clinicians involved in DBS surgery and programming should be aware of the differences in both stimulation settings, concerning electrodes geometry, stimulation modes as well as the impact of time. Therapeutic and side effects of permanent stimulation are not predictable by intraoperative test stimulation. Test stimulation may be an orientating test for very low thresholds of side effects instead.

The impact of white matter lesions on the cognitive outcome of subthalamic nucleus deep brain stimulation in Parkinson's disease.

OBJECTIVES: White Matter lesions (WML) are a risk factor for cognitive impairment in Parkinson's disease. There is no clear evidence of reduced general cognitive function after DBS. However, a subgroup of patients develops dementia rapidly after DBS despite careful patient selection processes. The aim of this study was to evaluate the load of WML as a possible risk factor for cognitive decline following STN DBS. PATIENTS AND METHODS: 40 PD-patients receiving bilateral STN-DBS were followed at least three years after surgery to detect dementia. All patients underwent comprehensive neuropsychological assessment and MRI before surgery. The extent of WML was assessed using an automated approach. WML volume was correlated to the onset of dementia and the decline of a cognitive composite score retrospectively. RESULTS: Patients with a rapid onset of dementia within one, respective three following DBS showed significant higher WML volumes compared to cognitive normal and MCI patients (55.8cm3±18.836 vs. 9.3cm3±12.2; p=0.002). The same significant association was found in a multivariable model, including the covariables age, gender and PD disease duration (p=0.01). WML volume was associated to the rate of decline in cognitive composite score within three years after DBS surgery (p=0.006; R2=0.40) after correction for age. CONCLUSIONS: Damaged white matter may lead to a reduced compensation of disconnections in cognitive circuits caused by the implantation of the DBS electrodes or by chronic stimulation. The role of WML as a prognostic factor for the cognitive outcome after DBS may be underestimated. The WML burden should be taken seriously in preoperative risk stratification.

Anesthesiologic regimen and intraoperative delirium in deep brain stimulation surgery for Parkinson's disease.

BACKGROUND: In many centers the standard anesthesiological care for deep brain stimulation (DBS) surgery in Parkinson's disease patients is an asleep-awake-asleep procedure. However, sedative drugs and anesthetics can compromise ventilation and hemodynamic stability during the operation and some patients develop a delirious mental state after the initial asleep phase. Further, these drugs interfere with the patient's alertness and cooperativeness, the quality of microelectrode recordings, and the recognition of undesired stimulation effects. In this study, we correlated the incidence of intraoperative delirium with the amount of anesthetics used intraoperatively. METHODS: The anesthesiologic approach is based on continuous presence and care, avoidance of negative suggestions, use of positive suggestions, and utilization of the patient's own resources. Clinical data from the operations were analyzed retrospectively, the occurrence of intraoperative delirium was extracted from patients' charts. The last 16 patients undergoing the standard conscious sedation procedure (group I) were compared to the first 22 (group II) psychologically-guided patients. RESULTS: The median amount of propofol decreased from 146 mg (group I) to 0mg (group II), remifentanyl from 0.70 mg to 0.00 mg, respectively (P<0.001 for propofol and remifentanyl). Using the new procedure, 12 of 22 patients (55%) in group II required no anesthetics. Intraoperative delirium was significantly less frequent in group II (P=0.03). CONCLUSIONS: The occurrence of intraoperative delirium correlates with the amount of intraoperative sedative and anesthetic drugs. Sedation and powerful analgesia are not prerequisites for patients' comfort during awake-DBS-surgery.

Outcome-related co-factors in 105 cases of vertebral osteomyelitis in a tertiary care hospital.

PURPOSE: Vertebral osteomyelitis (VO) is an infection of the vertebral body and the adjacent disc space. The aim of our study was to identify outcome-related co-factors of patients with VO treated in the last decade. METHODS AND RESULTS: We retrospectively identified 105 patients with VO (mean age 66.1 years) who had been treated at our institution from 2004 to 2011. The median time of hospitalization at our institution was 31.5 days, and 44 patients required intensive medical care. Back pain and fever were documented in 66.7 and 33.3 % of cases, respectively. The radiologic diagnosis of VO was made in 94.8 % of all obtained magnetic resonance imaging scans and in 66.2 % of all computed tomography (CT) scans. Biopsies were taken in 71 patients, and the causative organisms were identified in 56.2 % of patients, with Staphylococcus aureus being the predominant pathogen. Fifty-six patients underwent surgical treatment. During hospitalization, infectious complications were observed in 63 patients (60.0 %). The most common complications were psoas, paravertebral and epidural abscesses. Patients with S. aureus infections had a significantly higher rate of infectious complications than those without (76.5 vs. 40.3 %, respectively), and were more frequently treated in intensive care units (58.8 vs. 34.7 %, respectively). Overall in-hospital mortality rate was 12.4 %. Elevated C-reactive protein levels at admission, advanced age and a Charlson Comorbidity Index of ≥2 were associated with higher mortality. CONCLUSIONS: Magnetic resonance imaging currently is the imaging procedure of choice for the radiologic diagnosis of VO. Mortality is attributable in part to co-morbidities. However, infections with S. aureus are frequent in this patient population and are associated with a higher rate of complications and a trend towards higher mortality.

Levetiracetam compared to phenytoin for the prevention of postoperative seizures after craniotomy for intracranial tumours in patients without epilepsy.

Anticonvulsant drugs are frequently given after craniotomy. Phenytoin (PHT) is the most commonly used agent; levetiracetam (LEV) is a new anticonvulsant drug with fewer side effects. To compare the incidence of seizures in patients receiving either prophylactic PHT or LEV perioperatively, 971 patients undergoing a craniotomy were analysed retrospectively during a 2-year period. PHT was used routinely and LEV was administered when PHT was contraindicated. Seizures documented during the first 7 days after craniotomy were considered. A total of 235 patients were treated with an antiepileptic drug: 81 patients received LEV, and 154 patients, PHT. Two patients receiving LEV (2.5%) and seven receiving PHT (4.5%) had a seizure despite this treatment. No patient had a documented side effect or drug interaction. The data show that LEV may be an alternative option in patients with contraindications to PHT.

The vertebrate homolog of sulfide-quinone reductase is expressed in mitochondria of neuronal tissues.

Hydrogen sulfide (H2S) can be consumed by both invertebrates and vertebrates as an inorganic substrate. The pathway metabolizing H2S probably involves three mitochondrial enzymes, one of which is sulfide-quinone oxidoreductase (SQR), known as sulfide-quinone reductase-like protein (SQRDL) in vertebrates. Evidence from fission yeast suggests that SQR might have a role in regulating sulfide levels in the cell. Regulation might be essential for H2S to act as a gaseous transmitter (gasotransmitter). The brain is an organ with high activity of gasotransmitters, like nitric oxide (NO) and H2S, which are known to affect synaptic transmission. In this study, we provide evidence that SQRDL is expressed in the mammalian brain. Real-time polymerase chain reaction (PCR) showed an increase in the number of Sqrdl transcripts in the brain with increasing age. Cellular fractionation and subsequent analysis by Western blotting indicated that the protein is located in mitochondria, which is the site of sulfide consumption in the cell. With an immunohistochemical approach, we demonstrated that the SQRDL protein is expressed in neurons, oligodendrocytes, and endothelial cells. Taken together, our data suggest that brain tissue harbors the machinery required for local regulation of sulfide levels.

Analysis of risk factors influencing the development of severe dizziness in patients with vestibular schwannomas in the immediate postoperative phase.

OBJECTIVE: Dizziness, a common postoperative symptom in patients with vestibular schwannomas (VSs) has a negative effect on the course of recovery, particularly in patients with severe symptoms. Reports on incidence and possible risk factors contributing to these symptoms are inconsistent and sometimes even contradictory. In order to establish a profile of patients at risk of severe symptoms in the immediate postoperative phase we retrospectively analyzed data of patients with unilateral VSs focusing on the incidence of severe dizziness and nausea during the immediate postoperative period and up to 1 year after surgery. METHODS: In a retrospective study data of 104 consecutive patients with VSs were analyzed. All patients underwent microsurgical tumor resection via a lateral-suboccipital approach. Factors that were assumed to affect the development of severe dizziness, such as age, gender, tumor size, tumor side, and cranial nerve function, were analyzed by means of univariate and multivariate logistic regression analyses. A three step grading system was used to describe symptoms of patients included in this study: 0=no symptoms of dizziness, 1=slight dizziness including light-headedness or feeling of disequilibrium and 2=severe dizziness with nausea including imbalance or insecurity when walking, requiring antiemetic treatment. RESULTS: Data of 92 patients, 41 men and 51 women, were available for analyses. Mean age of treated patients was 53 years (range 17-81). There was no predilection of side (52.2% right/47.8% left). Before surgery 39 patients (42.4%) were symptom free (grade 0), 13 patients (14.1%) had slight symptoms (grade 1) and 40 patients (43.5%) suffered from severe symptoms (grade 2). Immediately after surgery two patients (2.2%) where symptom free (grade 0), 19 patients (20.7%) had slight symptoms (grade 1) and 71 patients (77.2%) suffered from severe symptoms (grade 2). All patients with grade 2 symptoms required antiemetic treatment ranging between 1 and 10 days (mean 4 days). Logistic regression analyses showed young age, large tumor size (T3/T4), female gender, and severe preoperative symptoms to be main factors increasing the odds for patients to develop severe symptoms postoperatively. CONCLUSION: Patients at risk to develop severe symptoms should receive antiemetic treatment even before surgery. If in doubt about the actual risk for a specific patient with a large tumor (T3 or T4) available data suggests that patients will benefit if antiemetic treatment is started early, even before surgery.

Coma after spinal anaesthesia in a patient with an unknown intracerebral tumour.

Spinal anaesthesia is contraindicated in patients with elevated intracranial pressure or space-occupying intracranial lesions. Drainage of the lumbar cerebrospinal fluid (CSF) can increase the pressure gradient between the spinal, supratentorial and infratentorial compartments. This can result in rapid herniation of the brain stem or occluding hydrocephalus. We present a case of a female patient with an occult brain tumour who received a spinal anaesthesia for an orthopaedic procedure. The primary course of anaesthesia was uneventful. Several hours after surgery, the patient became increasingly disoriented and agitated. The next day, she was found comatose. A computed tomogram of the head revealed herniation of the brain stem, resulting in an occluding hydrocephalus due to a prior not known infratentorial mass. By acute relieving of the intracranial pressure by external CSF drainage, the mass was removed 2 days later. The further post-operative course was uneventful and the patient was discharged from the hospital without neurological deficit 3 weeks after the primary surgery.

Elevated premorbid body mass index is not associated with poor neurological outcome in the subacute state after aneurysmal subarachnoid hemorrhage.

BACKGROUND: An elevated body mass index (BMI) is suggested to be a risk factor for a poor outcome after intracranial aneurysm rupture and is considered to be associated with cerebral infarction in patients with aneurysmal subarachnoid hemorrhage (SAH). The aim of this study was to analyze the association between permorbid BMI and neurological outcome. METHODS: In this retrospective study, the patients' BMI at the time of their admission to hospital was correlated to their neurological outcome as measured by the Glasgow outcome score after two weeks and two months of treatment. RESULTS: In contrast to other studies, there were no significant correlations between premorbid BMI and neurological outcome, shunt requirement, tracheotomy requirement and duration of stay on the intensive care unit (ICU). CONCLUSIONS: Overweight patients have no higher risk of a poor neurological outcome after aneurysmal SAH if premorbid risk factors such as hypertension and hyperglycemia are carefully modified throughout the period of critical care.

Extended extra- and intracerebral ulceration and brain abscess following self-mutilation in an auto-aggressive 51-year-old woman: case report.

In neurosurgical practice, the operative treatment of deep or infected wounds caused by auto-mutilation is quite rare, especially in the neurocranium. We present an extraordinary case of an auto-aggressive 51-year-old female suffering from a deeply ulcerated wound on the right frontal skull with consecutive brain abscess, caused manually with needles and forceps over a period of 8 months. The clinical course is present ed together with a description of the conservative and surgical regimen and is illustrated with photographs and CT and MRI images.

Cognitive decline as an important sign for an operable cause of dementia: chronic subdural haematoma.

BACKGROUND: Cognitive decline, slow psychomotor regression and confusion, especially in the elderly, often result in medical consultation. Frequently, these rather unspecific symptoms are interpreted as signs of beginning dementia. When mental regression is joined by tremor or motor deficits, neurodegenerative disease is commonly considered and the need for neuroimaging is underestimated. Chronic subdural haematoma (CSH) is known to be the most frequent type of intracranial bleeding, appearing mostly in the elderly after minor trauma with unspecific symptoms. The aim of this retrospective study was the identification of the leading clinical symptoms in patients with the diagnosis CSH who had been treated surgically in our Neurosurgical Department. PATIENTS AND METHOD: 356 patients with symptomatic CSH (225 male, 131 female; mean age 68.3 years), who were admitted to our Neurosurgical Department between 1992 and 2003, were included in the study. We reviewed the charts documenting preoperative clinical status, radiological signs, history of trauma, operative complications, postoperative clinical status, days of hospitalisation as well as gender and age. RESULTS: The primary surgical procedure performed in 343 patients (96.4%) was burr-hole trepanation. The leading preoperative symptoms were mnestic deficits (cognitive decline, confusion) in 192 patients (55.8%), followed by headache in 150 patients (45.5%) and motor deficit in 144 patients (41.1%). Furthermore, we found a statistically significant correlation (p<0.005) between the thickness of the left-sided haematoma and the symptoms aphasia and psychosyndrome. CONCLUSION: The leading clinical symptoms identified in our cohort were mnestic deficits, headache and motor deficit, signs that mostly appear at the beginning of demential diseases. Thus, CSH should be taken into account as an important differential diagnosis for demential and neurodegenerative diseases and neuroimaging should be demanded. Once a CSH is detected this way, the patient should be transferred to a neurosurgical department where an easy standard procedure may potentially lead to early recovery.

Pituitary dysfunction after aneurysmal subarachnoid hemorrhage.

Patients recovering from aneurysmal SAH often complain about weakness, fatigue and impaired cognitive skills. Pituitary dysfunction might be one possible reason for these complaints, as in patients with traumatic brain injury, hypopituitarism is known to be a common complication. There are only a few studies dealing with this problem in SAH patients, but these studies suggest that pituitary disturbances are very frequent after aneurysmal SAH. But anterior pituitary lobe disturbances might not be the only one responsible for some complaints or complications in patients suffering from aneurysmal SAH. Hyponatremia in the early state after SAH could be a hint for posterior pituitary lobe dysfunction.

[The importance of dental-based treatment shown on the case report of a pontine abscess caused by Streptococcus viridans]. / Die Bedeutung der zahnbezogenen Focussanierung am Fallbeispiel eines pontinen Abszesses durch Streptokokken der Viridans Gruppe.

BACKGROUND: The treatment of infectious oral lesions is an important prophylactic procedure preceding immunsuppressive therapy. The case reported underlines the importance of this treatment by showing severe complications of an infective dental focus in an immunocompetent patient. CASE REPORT: A 65 year old patient was referred to hospital due to neurological disorders including hypaesthesia, movement deficits, nausea and falls. Because of progressive aggravation with hemiplegia a craniotomy and biopsy of a suspicious area in the pons was performed. A brain stem abscess caused by Streptococcus viridans was diagnosed. Brain stem abscesses are very rare events who contribute to only about 0.6%-6% of all intracranial abscesses. The intraoral inspection revealed a periodontally diseased and carious affected dentition with many missing teeth. Other foci were ruled out. Because of persistency of the symptoms another operation with abscess drainage was performed. Afterwards the clinical symptoms improved but hemiplegia was still present. CONCLUSIONS: Even minor dental procedures as well as existence of a carious or periodontal disease may cause bacteremia with severe septical implications. Patients at risk (e.g. dieases of the heart valves or diabetes) should always treated with an antibiotic prophylaxis before treatment according to the guidelines of the DGZMK. All oro-pharyngeal infectious foci have to be treated sufficiently to prevent sceptical complications. Even more important is the prophylactic treatment preceding chemo- or radiation therapy.

A study of possible correlation between subarachnoid haemorrhage related vasospasm and the post-bleed blood platelet count chart in a Caucasian population.

INTRODUCTION: There has been controversy about the aetiology and pathophysiology of subarachnoid haemorrhage (SAH) related vasospasm. Several pathogenic factors like endothelin and adhesion molecules have been discussed. A recently published study concerning an exclusively Asian population suggested a relationship between SAH related vasospasm and the blood platelet count. The aim of our study was to examine this relationship in a European population. METHOD: We carefully reviewed 88 patients with aneurysmal SAH (54 females, 34 males; mean age 52.5 years, range from 22 to 78 years) treated in our centre with regard to the occurrence of vasospasm and the blood platelet count in a ten day interval after initial SAH. Symptomatic vasospasm was defined as a focal neurological deficit or deterioration in the level of consciousness with or without confirmation of infarction on a CT scan. Thirty-seven patients (42%) developed clinically relevant vasospasm. RESULTS: There was no statistically significant correlation between the blood platelet count chart (maximum and minimum values) and vasospasm or clinical outcome; we also found no gender or age-related influence on the above mentioned relationships. CONCLUSIONS: In our opinion there appears to be a difference between Caucasian and Asian populations regarding the influence of platelets in the pathophysiology of SAH and vasospasm.

Reliability of atlas-derived coordinates in deep brain stimulation.

BACKGROUND: In deep brain stimulation the way to define and localize the optimal target for the individual patient is still under debate. The objective of our study was to investigate the reliability of atlas derived data by comparing them with direct targeting on MR images. METHOD: We investigated 28 STN targets in 14 volunteers. The stereotactic coordinates of the dorso-lateral subthalamic nucleus (STN), were determined in 5 different ways for both STNs of each individual volunteer: 1. directly, on axial T2WI spin echo slices, 2. directly, on coronal T2WI spin echo slices and after fusion of data sets: 3. indirectly, on an axial atlas plate, 4. indirectly, on a coronal atlas plate, 5. indirectly, 12 mm lateral, 3 mm posterior and 3 mm inferior to mid-AC-PC. FINDINGS: The differences between MRI derived targets on axial vs. coronal slices were not statistically significant. After detection of the atlas derived targets the resulting x-coordinates were found more lateral than after direct detection on both, axial and coronal T2-weighted images (p < 0.001). On axial images y-coordinates were located more anterior (p = 0.240) on atlas derived targets and more posterior when target localizations were compared on coronal slices (p < 0.001). z-Coordinates were more superior after atlas targeting compared to MRI targeting (p < 0.001). Differences up to 6.21 mm occurred. CONCLUSIONS: Despite the limitations concerning image distortions and slice thickness, direct target planning on MRI, regarding our results, is more reliable than targeting solely based on atlas derived data. Only MRI gives us detailed information about the individual configurations of central structures in every single patient. However, targets, which are not detectable on MRI like the nucleus ventralis intermedius have to be planned using stereotactic atlas information. In these cases intra-operative micro-electrode recording might help to better define the target region.

Ultrasonic blood flow volume assessment in the extracranial internal carotid artery in arteriovenous malformations.

Angle-independent ultrasound assessment of the volume flow in the extracranial internal carotid artery (ICA) is a new approach to evaluate the perfusion status of the human brain. Normal values using a new technical device (Quantix ND, Cardiosonix Ltd, Israel) and correlation analysis to quantitative CBF measurements were recently published. Aim of this study was to evaluate this device in arteriovenous malformations where cerebral blood flow is known to be increased. Five patients suffering from large supratentorial arteriovenous malformations (AVM) could be examined. All patients showed pre-operatively elevated flow volumes in the internal carotid artery on the side harbouring the pathological lesion compared with normal values evaluated in 50 volunteers. The contralateral internal carotid artery showed volume flow values within the normal limit. After surgical resection of the malformation normal values could be measured in all patients. Pathological elevated increases in cerebral blood flow can be evaluated by ultrasonic blood flow volume assessment in the extracranial internal carotid artery. Therefore, the Quantix ND seems a valuable tool in diagnosing cerebral hyperemia.

Normal values of volume flow in the internal carotid artery measured by a new angle-independent Doppler technique for evaluating cerebral perfusion.

BACKGROUND: Cerebral blood flow is an important parameter when monitoring critically ill patients. Blood flow volume within the internal carotid artery (ICA) was shown to be correlated with the cerebral blood flow. The aim of our study was to provide normal values of the internal carotid artery volume flow using this new technology (QuantixND, Cardiosonix Ltd., Israel). METHOD: The QuantixND System is an angle-independent Doppler system that employs two digital high resolution ultrasound heads within one probe in an defined angle to each other. Thus several flow velocities within the vessel and the vessel diameter can be measured. 77 healthy patients (41 women, 36 men) were included and divided into age groups of ten-year intervals (mean age 48.9 years). Internal carotid artery flow was evaluated as well as physiological and hematological parameters (hematocrit, arterial blood pressure etc). FINDINGS: We found that the blood flow volume in the ICA decreased significantly with age. No side-to-side effects as well as no gender-related differences could be observed. There was no influence of hemoglobin, hematocrit and blood pressure in this healthy population. CONCLUSIONS: There is an age-related decrease in blood flow volume with age that can be easily and exactly determined by the use of the new angle-independent Doppler technique.

Quality of life after decompressive craniectomy in patients suffering from supratentorial brain ischemia.

BACKGROUND: Decompressive craniectomy in patients suffering from severe ischemic stroke in the middle cerebral artery territory (MCA) decreases mortality to near 30%. Additionally functional outcome in patients after early craniectomy seems to be better than in patients without surgery. The aim of this study was to investigate the quality of life of patients who were treated with a decompressive craniectomy for severe ischemic stroke. METHODS: We retrospectively investigated the patient records of 48 patients (26 men, mean age 48 years) suffering from ischemic strokes who underwent craniectomy since 1993. We registrated the preoperative neurological status, the diagnostic data as well as the operative procedure. The outcome was assessed using the Barthel Index, the Glasgow outcome score and a questionnaire to assess the quality of life according to Blau consisting of eleven items at follow-up. FINDINGS: The mortality rate was 26%, age correlated to mortality (44.5 versus 60.3 years GOS 1, mean, p<0.0006). Craniectomy without dura patch correlated to mortality (58% versus 14% GOS 1 with dura patch, p<0.005). The quality of life index was 6 points mean. The quality of life index did neither differ significantly between patients with left or right sided lesions nor in patients with and without aphasia. 83% of the surviving patients and/or dependents would agree to surgery in the future. CONCLUSION: Despite the fact that some patients remain in a poor neurological condition, quality of life after decompressive surgery for ischemic stroke seems to be acceptable to the patients.