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T Riegel

Publications and source records attributed to T Riegel.

17 recordsLinked to original sources
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↗
PubMed2005

[Preoperative marking of thoracic disc herniation].

INTRODUCTION: The operative therapy for thoracic disc herniations not only presents high demands on the operating surgeon, but also an additional difficulty in the certain identification of intraoperative height localisation. In this retrospective case analysis, we examine the value and practicability of CT-guided percutaneous marking for localisation of the appropriate vertebral segment. METHODS AND RESULTS: Between 1986 and 1998, eight patients were treated for a thoracic disc herniation. For these patients, the intraoperative height localisation was determined by a BV system. In two cases, healthy intervertebral discs were accidentally removed due to a faulty height localisation. DISCUSSION: At present, the intraoperative use of BV systems for localizing affected intervertebral segments in the operative therapy of a thoracic disc herniation is finding growing application.

Adult↗
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↗
PubMed2003

The Doppler-guided transfalcine venous approach in selected cases of vein of Galen malformations.

OBJECTIVE: This investigation was performed to evaluate the specific procedural issues and indications of a surgically assisted Doppler-guided endovascular transfalcine venous approach for the treatment of vein of Galen aneurysmal malformations (VGAM) in critically ill neonates. PATIENTS AND METHODS: Two neonates out of a clinical series of 15 children (8 males and 7 females) with vein of Galen malformations were treated by our neurovascular team, using a combined surgically assisted endovascular transfalcine approach. In the biplanar angiography room a radiographically guided craniotomy (1.5 cm) was placed over the cranial projection of the falciforme sinus. After craniotomy the orthograd flow of the falciforme sinus was identified by Doppler ultrasonography. The sinus was punctured by an i. v. cannula with injection port and was sutured to the skin. A microcatheter was maneuvered over a guide into the malformation under fluoroscopic control. For embolization Guglielmi electrolytically detachable platinum coils were placed into the malformation as an embolic agent. Neurological examination records, available MR images, computed tomographic scans, pre- and postembolization angiograms and follow-up data were analyzed. RESULTS: In both individuals the malformation was classified as VGAM. The follow-up was 6 and 7 months, respectively. No technique associated morbidity or mortality occurred in the present series. At discharge both selected neonates were in stable condition and the flow in the VGAMs could be significantly reduced by a combination of approaches including the venous transfalcine approach. Meanwhile, 6 months after birth one neonate died due to a deterioration of the pulmonary hypertension. CONCLUSIONS: Endovascular treatment is presently the most efficient strategy to allow neonates and infants survive the early manifestation of vein of Galen malformations and probably render a normal neurological development. Consequently, a combination of approaches in selected cases including the Doppler guided venous transfalcine route should be regarded as a preferential treatment modality, especially in patients with arterial vasospasms and venous stenosis.

Cerebral Angiography↗
PubMed2002

[Analysis of factors affecting the prognosis of vertebral metastases].

The goal of this study was to evaluate factors for the prognosis of patients with metastatic spinal tumors. 139 patients with vertebral metastases were studied. The modified Tokuhashi Score (a preoperative score composed of six parameters) and single factors were analysed with statistical methods. The modified Tokuhashi Score showed a significant correlation (p = 0,0019) with survival time of patients. Additionally, only the Karnofsky Index as single parameter showed statistically significant correlation(p = 0.0016). Regarding the logistic regression, primary tumor, age, sex and Karnofsky Index were identified as prognostic factors for survival time. This trial could demonstrate that the Tokuhashi Score is a successful predicting tool for the assessment of prognosis of patients with vertebral metastases.

Adult↗
PubMed2002

Helium (argon) plasma coagulation in neurosurgery. morphology of tissue damage and reparation.

Plasma coagulation, used in some neurosurgical operative settings, is currently under experimental investigation for the precise assessment of the kind and extent of tissue damage. We established a standardised trial to investigate the effects of helium (argon) plasma coagulation - H(A)PC - on rat brain tissue. The tissue reactions were observed with common methods of morphology including immunohistology and electron microscopy. A time dependent profile of the tissue reactions was performed from day 1 after operation up to 6 weeks. The tissue reaction consisted of clearly demarcated concentric zones. The depth of the lesion was about 1 mm maximally, at the beginning. Reparative forces acted at variance both in the different layers and at the edges versus the center of the damage. A manifold but reproducible picture emerges in the various compartments allowing the study of different aspects of organisation and/or elimination of tissue components. This study has demonstrated that a defined circumscribed and reproducible small lesion can be performed with H(A)PC. As in other areas of surgery, this technique has proven to be minimally traumatic. Clinical application of this technique in neurosurgery is therefore promising. In addition, H(A)PC lesions are obviously best suited for morphological studies of early and late reparative reactions in cells and tissues.

Animals↗
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

Image-guided placement of eye muscle electrodes for intraoperative cranial nerve monitoring.

OBJECTIVE: Monitoring of the oculomotor system during cranial base or brainstem surgery requires extraocular intraorbital insertion of electromyography electrodes. We investigated the use of image-guidance technology for anatomically correct intraorbital electrode placement. METHODS: For neuronavigation, an optical tracking system was used in a standard fashion. Needle electrodes were inserted percutaneously into the lateral rectus, inferior rectus, and superior oblique muscle along the axis of a hand-held pointer or by means of an electrode applicator to allow direct tracking with the navigation system. Electromyographic monitoring was performed by multichannel recordings of free running or evoked activity from the selected muscles. RESULTS: We have used this method in 10 patients; 5 had cranial base tumors and 5 underwent operations for brainstem lesions. No additional instruments or resources were required compared with the routine setup, and no intraorbital structures were injured. Successful monitoring of oculomotor, trochlear, or abducent nerve function was possible in each case. CONCLUSION: This method may have the potential to increase the safety and success rate of intraoperative electro-ophthalmography during microsurgery focused on preservation of neurological function.

Abducens Nerve↗
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↗
PubMed2000

Relationships of virtual reality neuroendoscopic simulations to actual imaging.

Advances in computer technology have permitted virtual reality images of the ventricular system. To determine the relevance of these images we have compared virtual reality simulations of the ventricular system with endoscopic findings in three patients. The virtual fly-through can be simulated after definition of waypoints. Flight objects of interest can be viewed from all sides. Important drawbacks are that filigree structures may be missed and blood vessels cannot be distinguished clearly. However, virtual endoscopy can presently be used as a planning tool or for training and has future potential for neurosurgery.

Adult↗
PubMed2000

The significance of intrathecal opioid therapy for the treatment of neuropathic cancer pain conditions.

The effectiveness of intrathecal opioid therapy when applied to different pain mechanisms, in particular neuropathic and nociceptive pain conditions, was studied retrospectively in 43 patients suffering from cancer pain. On the basis of clinical and radiological data, the pain mechanisms were categorized as nociceptive (n = 23) and neuropathic (n = 20). The average duration of treatment of nociceptive pain was 5 months, of neuropathic pain only 2.5 months. The initial median reduction of pain with intrathecal opioid therapy was 77.8% for nociceptive and 61.1% for neuropathic pain. Long-term results with patients suffering nociceptive pain showed a continuing good median pain reduction of 66.7%. Patients suffering from neuropathic pain showed poor long-term results (11.1% median pain reduction). Neuropathic pain in the extremities reacted least to the application of intrathecal opioids. Optimal results were obtained for nociceptive pain in the trunk area of the body.

Adult↗
PubMed1999

Application of new electrosurgical devices and probes in endoscopic neurosurgery.

Complex demands and new indications in neurosurgery have led to the need for new electrosurgical generators (ESUs). For the first time, newly developed, automatically controlled ESUs make it possible to use extremely small and flexible instruments safely and to achieve reproducible microcuts and microcoagulations. These specifications make them suitable for neuroendoscopic interventions. In a series of more than one hundred patients with different intracranial and intraspinal pathologies the new electrosurgical devices and probes were used not only for coagulation but also for cutting. The main indications were endoscopic ventriculo-cisternostomy, ventriculo-cystostomy, and membranectomy. The electrosurgical generators as well as the bipolar microcoagulation and -cutting probes proved to be safe and effective for neuroendoscopic interventions.

Electrocoagulation↗
PubMed1994

Endoscopic anatomy of the third ventricle.

42 cadaver brains in situ were examined endoscopically to work out topographical anatomical landmarks for orientation. The endoscopic route from the chosen precoronal trepanation point to the defined ventricular landmarks has been measured in 22 cases. The identification and measurements of the anatomical landmarks are helpful for safe and atraumatic endoscopical navigation within the ventricular system. Furthermore this article describes and discusses cerebral lesions during ventriculoscopy.

Brain Mapping↗
PubMed1994

A preliminary study of the usefulness of the Behavior Assessment Systems for Children in the evaluation of mental health needs in a Head Start population.

122 parents and 18 teachers rated Head Start children on the preschool version of the Behavioral Assessment System for Children. Parents tended to rate their children as having greater problem scores than did their teacher, but both ratings, when compared to general norms, were within normal limits. Low to moderate correlations were found for the same scales on Parent and Teacher forms. Teachers rated children in the center program as having fewer problems than their home-based peers, while parents evaluated center children as having better adaptive behavior than children in the home-based program. Boys had more clinical problems than girls, while girls were rated as showing more adaptive behavior than boys. The usefulness and need for further research on this assessment are mentioned.

Attention Deficit Disorder with Hyperactivity↗
PubMedDate not supplied

Argon plasma coagulation (APC) in brain tumor surgery: experimental study and clinical experiences.

OBJECTIVE: The present study aims to provide preliminary results of the thermal effects on rat brain tissue after argon plasma coagulation (APC). It also presents and discusses the clinical experiences in the treatment of brain tumor using APC. MATERIALS AND METHODS: A controlled study of APC in the rat brain was conducted. Twelve rats were randomly divided into 2 experimental groups. In the first group (n = 6), histopathological evaluation was performed 2 days following the coagulation. In the second group (n = 6), the evaluation was performed 12 days post operation. In a prospective study of APC-treated tumor tissue in 3 patients, the depth of plasma penetration and histological alteration were evaluated. RESULTS: In the animal experiment, extent of tissue defect became significantly smaller after 12 days (p = 0.010). The maximum depth of tissue alteration after APC application was limited to 2.15 mm (range: 1.5-2.15 mm) at day 2. The histological alteration of tissue after the thermal injury can be divided into 3 zones. In addition, the depth of tissue alteration in the APC-treated human brain tumor was measured in vertical and horizontal planes under light microscope. Similar to the animal experiment result, penetration of the plasma energy in human brain tumors was limited to a maximum of 2.13 mm (range: 1.6-2.13 mm). CONCLUSION: The limited depth of energy penetration may confirm APC as a safe and beneficial tool for coagulation of human brain tissue. However, further clinical studies are required to evaluate the suitability and indications of this method in brain tumor treatment.

Animals↗