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D Hellwig

Publications and source records attributed to D Hellwig.

At least 19 recordsLinked to original sources
PubMed2006

Striatal FP-CIT uptake differs in the subtypes of early Parkinson's disease.

In idiopathic Parkinson's disease (PD), a tremor-dominant type (TDT), an akinetic-rigid type (ART), and a mixed type (MT) are distinguished. We compared cerebral [I-123]FP-CIT SPECT in the PD subtypes (67 patients Hoehn and Yahr stage 1:26 with ART, 19 with MT, 22 with TDT). We measured the ratios putamen/occipital lobe binding and caudate nucleus/occipital lobe binding. Parkinsonian motor symptoms were quantified by UPDRS motor scale. In both putamen and caudate nucleus contralateral to the clinically affected body side TDT patients showed a significantly higher FP-CIT uptake than ART or MT patients (ANOVA; p<0.01). Contralateral putamen and caudate nucleus FP-CIT uptake correlated significantly with severity of rigidity (p<0.01) and hypokinesia (p<0.01) but not with severity of resting or postural tremor (p>0.05). The missing correlation between striatal FP-CIT uptake and tremor suggests, that further systems besides the nigrostriatal dopaminergic system may contribute to generation of parkinsonian tremor.

Adult↗
PubMed2006

Comparative experimental study of argon plasma and bipolar coagulation techniques.

BACKGROUND: Argon plasma coagulation (APC) is based on the principle of ionised argon creating conductive plasma between an activating electrode and tissue surface and is used as an effective alternative coagulation technique in various surgical disciplines. This trial aims to compare thermal injury in rat brain caused by APC and conventional bipolar coagulation technique. METHODS: A controlled study design with constant power setting and application time was established. Twenty rats were randomised into the APC and bipolar groups. Each group of ten rats had 20 treated lesions. Early and late histopathological changes, as well as maximum extent of the lesion after 48 hours (h) and 12 days were studied in overall 20 lesions. FINDINGS: Although the maximum depth of the lesions was different in APC (2.2 mm) and bipolar (1.8 mm) groups after 48 h, this did not achieve statistical significance (p=0.151). The superficially coagulated area was significantly larger after APC compared with the bipolar technique at the 48 h time point (p=0.032). After twelve days there were no differences in penetration depth (p=0.310) or coagulated area (p=0.222). CONCLUSION: Tissue defects after APC application on rat brains were comparable to conventional bipolar technique in this trial. The results suggest that argon plasma coagulation (APC) is an effective coagulation technique.

Animals↗
PubMed2006

[Abscess at the implant site following apical parodontitis. Hardware-related complications of deep brain stimulation].

Deep brain stimulation of the subthalamic nucleus is an important treatment option for advanced stages of idiopathic Parkinson's disease, leading to significant improvement of motor symptoms in suited patients. Hardware-related complications such as technical malfunction, skin erosion, and infections however cause patient discomfort and additional expense. The patient presented here suffered a putrid infection of the impulse generator site following only local dental treatment of apical parodontitis. Therefore, prophylactic systemic antibiotic treatment is recommended for patients with implanted deep brain stimulation devices in case of operations, dental procedures, or infectious disease.

Aged↗
PubMed2005

Double electrodes simultaneous stimulation and implantation technique in deep brain stimulation.

Posttraumatic tremor is often one of the causes of disability in head injury patients. Usually, pharmacotherapy for this type of tremor is not effective. Since early 1970s, surgical ablation of the ventral thalamus has been used to treat various types of tremor. Nowadays, deep brain stimulation (DBS) confirms its efficacy in alleviating different forms of tremor, including posttraumatic tremor. Such therapy has been reported achieving around 80% success rate in the treatment of posttraumatic tremor. These successful results suggest that the application of DBS therapy can be considered as one of the alternative treatments for minimizing the tremor occurring from different pathologies.

Adult↗
PubMed2004

Value of FDG PET in the management of NSCLC.

Metabolic imaging with positron emission tomography (PET) using 18F-fluoro-2-deoxy-glucose (FDG) has been accepted as an important imaging modality in lung cancer. FDG PET may have important impacts on the management of lung-cancer patients, for instance by improvement of locoregional (mediastinal) and extrathoracic staging (unexpected metastases). Interesting findings have now been reported in the response assessment to induction therapy providing results of greater prognostic significance than that obtained by conventional imaging methods. In the field of thoracic irradiation, FDG PET may provide advantages in terms of reduced toxicity, treatment intensification, better local tumour control and increased survival.

Carcinoma, Non-Small-Cell Lung↗
PubMed2004

Clinical application of neuro-navigation in a series of single burr-hole procedures.

With recent developments in computer technology and the improvement of neuroimaging, modern optical neuro-navigation systems are increasingly being used in neurosurgery. In this study, we present our experience with 51 operations using a frameless optical navigation system in a variety of single burr-hole procedures. The procedures include neuroendoscopic surgery, frameless stereotactic biopsy, cyst aspiration and catheter placement. Both the VectorVision and the VectorVision(2) neuro-navigation systems (BrainLab AG, Munich, Germany) were used. The reliability and accuracy of the neuro-navigation system, postoperative complications and the clinical usefulness of image-guidance were analyzed. The navigation system worked properly in all 51 neurosurgical cases. Exact planning of the approach and determination of the ideal trajectory were possible in all cases. The mean registration error of the system, given as a computer-calculated value, was 2.1 mm (0.4-3.1 mm). Postoperative clinical evaluations and imaging were performed on every patient in order to confirm the success of the surgical procedure. All patients recovered well and without any postoperative complications. We conclude that image guidance in single burr-hole procedures provides a high degree of accuracy in lesion targeting, permits good anatomical orientation and minimizes brain trauma. The navigation system has proven to be a helpful tool since it increases the safety of single burr-hole procedures.

Adolescent↗
PubMed2004

Image-guided motor cortex stimulation in patients with central pain.

According to recent clinical data, motor cortex stimulation (MCS) is an alternative treatment for central pain syndromes. We present our minimally invasive technique of image guidance for the placement of the motor cortex-stimulating electrode and assess the clinical usefulness of both neuronavigation and vacuum headrest. Five patients suffering from central pain underwent MCS with the guidance of a frameless stereotactic system (BrainLab AG, Munich, Germany). The neuronavigation was used for identification of the precentral gyrus and accurate planning of the single burr hole. The exact location was reconfirmed by an intraoperative stimulation test. Postoperative clinical and neuroradiological evaluations were performed in each patient. The navigation system worked properly in all 5 neurosurgical cases. Determination of the placement of stimulating electrode was possible in every case. All patients obtained postoperative pain relief. No surgical complication occurred, and the postoperative course was uneventful in all patients. This preliminary experience may confirm image guidance as a useful tool for the surgery of MCS. Additionally, minimal and safe exposure can be achieved using a single burr hole and vacuum headrest.

Aged↗
PubMed2004

Progressive dementia caused by Hashimoto's encephalopathy -- report of two cases.

Dementia induced by Hashimoto's encephalopathy (HE) seems to be a rare condition. We report on two patients, who revealed a syndrome consisting of a rapid progressive dementia with myocloni. In both patients, the detection of antithyroid antibodies enabled the diagnosis of HE. The symptoms receded completely during a high-dose glucocorticoid therapy. In patients with rapidly progressive dementia or with dementia of unknown origin, HE should be considered.

Adult↗
PubMed2004

Position of nuclear medicine modalities in the diagnostic workup of cancer patients: lung cancer.

This review summarizes the current literature and tries to define the status of nuclear medicine in the clinical workup of lung cancer patients. Nuclear medicine procedures and positron emission tomography (PET) with the EMEA-approved radiopharmaceutical fluorodeo-xyglucose (FDG) are indicated for the characterization of lung lesions; the nodal staging of non-small cell lung cancer (NSCLC); the detection of distant metastases; and for the diagnosis of recurrent disease. Recent studies have shown the clinical efficacy of nuclear medicine and especially of FDG-PET in the workup of lung cancer patients and its significant impact on patients' management. Conventional nuclear medicine procedures are established for the pre-therapeutic assessment of pulmonary perfusion and function (lung perfusion and ventilation scintigraphy) and for the detection of bone metastases (skeletal scintigraphy). In studies in thousands of patients, FDG-PET has been proved to be the most accurate non-invasive diagnostic test for the characterization of lung nodules and masses. It can be recommended at least for patients with increased risk at surgery. FDG-PET should be applied in candidates for surgery of lung cancer, as mediastinoscopy may be omitted if PET shows no metastases in the mediastinum, and because FDG-PET avoids futile surgery by a more accurate selection of patients, especially by the detection of unexpected distant metastases. In candidates for thoracic radiotherapy, FDG-PET can help to exclude extrathoracic disease which needs systemic treatment and to better define the target volume for radiation therapy. The time has come for FDG-PET to find its place in new guidelines for the workup of lung cancer patients.

Bone Neoplasms↗
PubMed2003

[PET with (18)F-fluorodeoxyglucose for staging of non-small cell lung cancer].

AIMS: To evaluate studies on the use of positron emission tomography with the glucose analog (18)F-fluoro-deoxyglucose (FDG-PET) for the preoperative staging of patients with non-small cell lung cancer (NSCLC) according to the criteria of evidence based medicine and to discuss the cost-effectiveness of the technique. METHODS: Clinical studies published between 1995 and 2002 on the preoperative staging of non-small cell lung cancer were used for this analysis. Studies that did not meet the criteria published by the European Agency for the Evaluation of Medicinal Products (EMEA) were excluded. The validity of the studies was evaluated by a standardized rating system developed by the Agency for Health Care Policy and Research (AHCPR). RESULTS: For the detection of mediastinal lymph node metastases the mean sensitivity and specificity of FDG-PET on a patient basis is 85% and 87% (16 studies, 1355 patients). In studies that compared FDG-PET and computed tomography (CT) the mean sensitivity of CT was 66% at a specificity of 71%. In the detection of distant metastases FDG-PET correctly changed the tumor stage in 18% of the patients when compared to CT based staging (10 studies, 1073 patients). Five cost effectiveness analyses from the USA, Japan, and Germany concluded that FDG-PET improves the outcome of treatment at reduced or only slightly increased overall costs. Improvement of patient outcome was also demonstrated in a randomized trial, which found that the risk of a futile thoracotomy was reduced by 51% (p=0.003) when FDG-PET was added to the preoperative staging. CONCLUSION: According to the criteria of the AHCPR the use of FDG-PET for detection of mediastinal lymph node and distant metastases is documented at a level of evidence Ia and Ib, respectively. Since systematic analyses also indicate a favorable cost-effectiveness ratio FDG-PET has to be considered as "strictly indicated" for the preoperative staging of non-small cell lung cancer.

Carcinoma, Non-Small-Cell Lung↗
PubMed2002

Evaluation of healthcare utilization and health status of patients with Parkinson's disease treated with deep brain stimulation of the subthalamic nucleus.

OBJECTIVE: To assess the effects on motor functioning, health status and direct medical costs of high-frequency stimulation of the subthalamic nucleus (DBS-STN) in patients with idiopathic Parkinson's disease (PD). In addition, the cost-effectiveness of DBS-STN vs. drug treatment was investigated. METHODS: 16 consecutive patients with PD from two centers (Düsseldorf/Cologne; Kiel) treated by DBS-STN were prospectively evaluated. Clinical evaluations were done at baseline and 1, 3, 6, 12 months following surgery by means of the Unified Parkinson's disease Rating Scale (UPDRS). Health status of PD patients was assessed using the Sickness Impact Profile (SIP) at baseline and 6 months following surgery. Relevant economic data were taken from the medical records and costs (1999) were derived from different German medical economic resources. Costs were determined from the perspective of the health care provider. RESULTS: Following DBS-STN UPDRS scores (subscores and sum score) as well as health status improved considerably in PD patients. The overall SIP score and the physical dimension score (p < 0.009) were significantly different (p < 0.01) six month after surgery compared with baseline values. Mean costs of DM 40,020 (US dollars 20,810, EURO 20,410, GB pounds 12,810) per patient were spent during the 12 month observation period for in-patient and out-patient care. These expenses included already the costs for the electronic device for bilateral stimulation. Following DBS-STN medication was considerably reduced. Mean daily drug costs at baseline were DM 46.7+/-21.8 (US dollars 24, EURO 24, GB pounds 15) and DM 18.3+/-17.7 (US dollars 10, EURO 9, GB pounds 6) at 12 months following DBS-STN. Accounting for the decreased drug consumption, total annual costs amounted to DM 31,400 (US dollars 16,330, EURO 16,010, GB pounds 10,050). Further, we estimated the incremental cost effectiveness as DBS-STN had higher costs but was more effective than baseline treatment. The incremental total cost-effectiveness ratio for DBS-STN was DM 1.800 (US dollars 940, EURO 920, GB pounds 580) for one point decrease of the UPDRS. CONCLUSION: DBS-STN is an effective treatment that considerably alleviates the severity of signs and symptoms and improves the health status of patients with PD. Compared with drug treatment, however, the expenditures associated with DBS-STN are increased when only direct medical costs are considered in a one year horizon. However, on a long-term basis costs will decrease considerably because of the reduction of the drug expenditure and improved functioning in all activities of daily living. To adequately evaluate the cost-effectiveness of DBS-STN compared with standard drug regimen for PD it is necessary to include direct, indirect and intangible costs on a long-term basis and under standardized circumstances.

Aged↗
PubMed2002

Initial evaluation of the feasibility of single photon emission tomography with p-[123 I]iodo-L-phenylalanine for routine brain tumour imaging.

p-[123I]iodo-L-phenylalanine (IPA) is a recently described radiopharmaceutical which is highly accumulated in gliomas. The present investigation was designed to evaluate the feasibility of single photon emission tomography (SPET) with IPA to image brain tumours under routine clinical conditions. Using a dual- and a triple-headed SPET camera, whole-body kinetic and brain SPET, as well as plasma, urinary and dosimetric analysis were determined in four patients with gliomas after intravenous injection of IPA. Results obtained by IPA SPET were retrospectively compared with histopathology, magnetic resonance imaging and positron emission tomography with [18F]fluorodeoxyglucose. Tumour lesions were clearly demonstrated by IPA SPET at 30 min, 1h and 4.5h post-injection, even in patients with low grade gliomas. In patients with glioblastoma, excellent visualization of the tumour was possible even at 7h p.i., indicative of the high retention of the radiopharmaceutical in cerebral gliomas. Analysis of the radioactivity in plasma and urine attested to the high in vivo stability of IPA. Blood clearance was rapid (> 65% after 10 min) and IPA was excreted predominantly by the kidneys, the urinary radioactivity excretion ranging from 27% at 1h to 54% of injected doses at 5h p.i. The average effective dose for adults was estimated to be 0.0152mSv*MBq(-1), leading to an effective dose of 3.8mSv in a typical brain SPET investigation with 250 MBq IPA. This result strongly suggests that IPA is a potentially valuable brain tumour imaging agent for widespread clinical studies with SPET. Its high specific tumour uptake and retention even in low grade gliomas represent a major advantage compared to presently available SPET radiopharmaceuticals. Moreover, the radiation dose estimates indicate that clinical use of IPA will result in acceptable radiation dose levels in humans.

Adult↗
PubMed2001

Operative management of third ventriculostomy in cases of thickened, non-translucent third ventricular floor: technical note.

Today, endoscopic third ventriculostomy is an established operative modality in occlusive hydrocephalus. The elemental step in third ventriculostomy is the perforation of the floor of the third ventricle. Especially with a thickened third ventricular floor, anatomical orientation can be disturbed and perforation of third ventricular floor technically difficult. The combination of a neuronavigation system with an endoscope provides interactive image-guided neuroendoscopy. Exact planning of the approach is thus possible and the ideal trajectory to the target area can be determined. We have combined interactive neuronavigation and intraoperative fluoroscopy for incorporating real-time feedback to optimize endoscopy in patients with a thickened third ventricular floor selected for third ventriculostomy.

Endoscopy↗
PubMed2001

Incorrect vector after calibration of surgical instruments for image guidance. The problem and the solution: technical note.

Recently, the use of intra-operative image guidance has gained an increasing role in neurosurgery for both spinal and cerebral interventions. Some modern neuronavigation systems are able to register any surgical instrument and create a virtual pointer. A virtual elongation of the digitized instrument is frequently used for neuroendoscopic procedures and spinal instrumentation. The instrument is equipped with a universal instrument adapter clamp and digitized by touching the tip of the instrument into a calibration cone. An algorithm calculates the vector of the instrument using two points: the tip of the instrument, and the geometrical center of the instrument adapter geometry. If a virtual elongation of the calibrated instrument is performed, the neuronavigation software may calculate an incorrect virtual target point. We developed an instrument calibration matrix (ICM) that automatically calibrates the correct vector, tip, and diameter of the instrument used for image-guided surgery. The ICM is easy to handle and does not cause a time delay during surgery. Virtual elongation of the surgical instruments shows correct anatomic data, which are fundamental for planning ventricular tapping and spinal screw placement in particular. The instrument calibration matrix is essential if surgical instruments are digitized and used for neuronavigation. It helps to avoid mis-planning of surgical vectors and mis-placement of the used instruments.

Calibration↗
PubMed2001

[Accuracy of positron emission tomography with fluorine-18-fluoro-deoxyglucose].

BACKGROUND: : FDG-PET is a powerful tool for the diagnostic workup of patients with lung cancer. A reduced sensitivity of FDG-PET for the evaluation of lung lesions was reported for bronchioloalveolar carcinoma (BAC). No literature exists about the diagnostic efficacy of FDG-PET in the staging of BAC. METHODS: : Out of a series of subsequent 630 untreated patients with the final diagnosis of lung cancer, who underwent FDG-PET, all patients with BAC were evaluated with respect to tumour detection, N-staging, and M-staging. RESULTS: : 35 patients (5.6 %) had BAC, 22 in a localized form (8 x pT1, 14 x pT2), 13 in a disseminated stage. FDG-PET correctly identified 19/22 cases with localized forms. Two of the missed one were classified as pT1. All disseminated forms of BAC were detected. Standardized uptake values (SUV) ranged from 0.9 to 23.3 (mean +/- SD: 11.6 +/- 5.1). Accuracy of N-staging was comparable to known results in lung cancer (FDG-PET 80 %, CT 64 %). With respect to M-staging, sensitivity of FDG-PET was as follows: M1(HEP): 2/3 (67 %), M1(PUL): 7/8 (88 %), M1(OSS): 1/1 (100 %). CONCLUSIONS: : With some limitations in small localized tumours FDG-PET can detect and stage BAC with an accuracy which is identical to that for other histological types of non-small cell lung cancer.

Carcinoma, Non-Small-Cell Lung↗
PubMed2001

[Meta-analysis of the efficacy of positron emission tomography with F-18-fluorodeoxyglucose in lung tumors. Basis for discussion of the German Consensus Conference on PET in Oncology 2000].

BACKGROUND: : To analyse current literature on FDG-PET for evaluation of lung lesions, N-staging, M-staging, and recurrence of lung cancer for the third German Consensus Conference on PET in oncology. METHODS: Specialists in nuclear medicine, pneumology, radiation oncology, diagnostic radiology, and thoracic surgery reviewed the relevant literature as listed in MEDLINE from 1985 to 1999 for further analysis. Out of the published data cumulative test parameters and summary receiver operating characteristic curves (sROC curves) were computed. RESULTS: Sensitivity, specificity, and accuracy of FDG-PET are 96 %, 80 %, 91 % for evaluating lung lesions (15 studies with at least 35, in total 1144 patients). With corresponding values of 88 %, 92 %, 91 % (20 studies, 1292 patients) for N-staging FDG-PET is superior to CT with 65 %, 76 %, 73 % (19 studies, 1268 patients). With 94 %, 97 %, 96 % (4 studies, 336 patients) M-staging with FDG-PET is very accurate and changed therapeutic management in 18 % of the cases (8 studies, 695 patients), unexpected extrathoracic metastases were found in 12 % (7 studies, 581 patients). FDG-PET is the most accurate non-invasive method to evaluate suspected adrenal metastases (3 studies, 263 patients, sensitivity 96 %, specificity 99 %, accuracy 98 %). Recurrence is detected accurately (4 studies, 224 patients, sensitivity 99 %, specificity 89 %, accuracy 95 %). CONCLUSIONS: Studies with in total more than 1000 patients show the high diagnostic efficacy of FDG-PET and its superiority to conventional imaging in lung cancer. Based on this analysis the third German Consensus Conference on PET in oncology evaluated FDG-PET on lung cancer. 1a-indications are evaluation of lung nodules in patients at risk for complications during surgery, N-staging, M-staging (except brain), and detection of recurrence.

Fluorodeoxyglucose F18↗
PubMed2001

Frameless navigation and endoscopy.

OBJECT: Frameless computerized neuronavigation has been increasingly used in intracranial endoscopic neurosurgery. However, clear indications for the application of neuronavigation in neuroendoscopy have not yet been defined. The purpose of this study was to determine in which intracranial neuroendoscopic procedures frameless neuronavigation is necessary and really beneficial compared with a free-hand endoscopic approach. METHODS: A frameless infrared-based computerized neuronavi- gation system was used in 44 patients who underwent intracranial endoscopic procedures, including 13 third ventriculostomies, nine aqueductoplasties. eight intraventricular tumor biopsy procedures or resections, six cystocisternostomies in arachnoid cysts, five colloid cyst removals, four septostomies in multiloculated hydrocephalus, four cystoventriculostomies in intraparenchymal cysts, two aqueductal stent placements, and fenestration of one pineal cyst and one cavum veli interpositi. All interventions were successfully accomplished. In all procedures, the navigational system guided the surgeons precisely to the target. Navigational tracking was helpful in entering small ventricles, in approaching the posterior third ventricle when the foramen of Monro was narrow, and in selecting the best approach to colloid cysts. Neuronavigation was essential in some cystic lesions lacking clear landmarks, such as intraparenchymal cysts or multiloculated hydrocephalus. Neuronavigation was not necessary in standard third ventriculostomies, tumor biopsy procedures, and large sylvian arachnoid cysts, or for approaching the posterior third ventricle when the foramen of Monro was enlarged. CONCLUSIONS: Frameless neuronavigation has proven to be accurate, reliable, and extremely useful in selected intracranial neuroendoscopic procedures. Image-guided neuroendoscopy improved the accuracy of the endoscopic approach and minimized brain trauma.

Biopsy↗