Search PubMed⌕ Search

Biomedical subjects

R Bale

Publications and source records attributed to R Bale.

At least 19 recordsLinked to original sources
PubMed2005

[Development of an active robot system for multi-modal paranasal sinus surgery].

BACKGROUND: Severe complications in endoscopic paranasal sinus surgery are rare, however, when they occur they are often fatal. Injuries to the optic nerve or the internal carotid artery mostly occur after penetration of the sphenoid sinus' anterior wall. METHODS: We present the robot system "A 73" with its newly designed 4-canal-microendoscope and special instruments that meets the demands of endoscopic paranasal sinus surgery. A fully automated perforation of the sphenoid sinus' anterior wall was performed in five cadaveric specimens. RESULTS: The sphenoid sinus' anterior wall could be perforated without damaging the surrounding structures in all cases. Subsequently, the approach was enlarged to the desired diameter using telemanipulation mode. The analysis of both the transformation error and intraopertive accuracy showed values in the submillimeter range. CONCLUSIONS: Using a newly developed robotic system, a fully automated perforation of the sphenoid sinus' anterior wall was performed precisely and reproducibly. This approach can be enlarged in a telemanipulation mode.

Cadaver↗
PubMed2004

Robot-assisted mediastinal parathyroidectomy.

We report the first case of robot-assisted thoracoscopic resection of a mediastinal parathyroid adenoma in the aorto-pulmonary window. Intervention planning was based on preoperative CT-MIBI image fusion, a new imaging modality that enabled reliable and precise localization of the parathyroid. The technique consists of taking MIBI-SPECT and CT separately, using a fixation unit that provides reproducible positioning of the patients head and neck. The data sets are then superimposed upon each other using special software. After the localization process, a minimally invasive operation was performed using the DaVinci operating robot. The procedure proved not only to be feasible but also safe and not time-consuming. The postoperative course was uneventful, and the patient was discharged 4 days postoperatively. Compared to conventional thoracoscopic surgery, the robotic operating system provides better visualization of the operating field and facilitates the movement of the instruments. Precise preoperative imaging enables the careful planning of robot-assisted surgery for ectopic parathyroids located at relatively inaccessible regions such as the anterior mediastinum.

Adenoma↗
PubMed2003

Neuroendoscopy based on computer assisted adjustment of the endoscope holder in the laboratory.

OBJECTIVE: We present our initial clinical experience with a novel technique of frameless stereotactic neuroendoscopy using a neuronavigation system, a specially designed aiming device (endoscope holder/targeting device) combined with a vacuum-mouthpiece based head holder. Due to the reproducibility of patient immobilization in the fixation system, the endoscope holder can be adjusted in the laboratory in the absence of the patient. METHODS: An individual vacuum-mouthpiece was fabricated. The patients were scanned with an external reference frame attached to this mouthpiece and the images were transferred to the neuronavigation system. Determination of the path, mouthpiece-based registration and adjustment of the targeting device were performed the day before surgery in the absence of the patient. In the OR the patient was repositioned and the endoscope was introduced through the preadjusted aiming device to the precalculated depth. RESULTS: The novel technique was successfully used for frameless endoscopic navigation in five patients. Three endoscopic third ventriculostomies in adults, one endoscopic septostomy due to unilateral hydrocephalus in an adult female patient and one endoscopic ventriculo-cysto cisternostomy in a 20-month-old girl with a suprasellar arachnoid cyst, were performed with excellent clinical results and without technical complications. CONCLUSION: Our initial experience indicates that frameless stereotaxy, in combination with a relocatable head holder and a special targeting device, allows for precise and preplanned advancement of the neuroendoscope, reducing or even eliminating intraoperative registration and endoscope trajectory adjustments, thus substantially reducing OR time. Due to the non-invasive but rigid immobilization method, neuronavigation can also be performed in children under 2 years of age.

Adult↗
PubMed2002

[Modern CT diagnosis of acute thoracic and abdominal trauma].

PURPOSE: To evaluate a modified algorithm in the diagnostic management of polytraumatized patients by using whole body multislice CT (MSCT) as primary diagnostic tool. MATERIAL AND METHODS: Between June 1999 and October 2000 532 polytraumatized patients were referred to the emergency department. 336 polytraumatized patients were primarily evaluated using whole body MSCT according to the "Innsbruck Emergency Algorithm". MSCT is performed immediately after cardiovascular stabilization of the patient. During the initial stabilization period free intraabdominal fluid is excluded or demonstrated by abdominal ultrasound. Time-consuming conventional radiographs are omitted with exception of an optional chest X-ray. In patients with suspected or obvious arterial injuries or fractures the multislice-CT-dataset is used to perform 2D and 3D reconstructions in order to optimize visualization of additional skeletal and vascular injuries. RESULTS: By means of whole body MSCT it was possible to detect all injuries. The diagnostic advantage of whole body MSCT as compared to conventional X-ray was analyzed in 111 consecutive polytraumatized patients with an injury severity score (ISS) of 34.77. The early use of MSCT shortened the time for diagnostic work-up substantially (approximately 50%). CONCLUSION: Whole body multislice-CT used as primary diagnostic tool in the management of polytraumatized patients allows for a fast, accurate and comprehensive diagnostic work-up.

Abdominal Injuries↗
PubMed2002

[Modern CT diagnosis of acute thoracic and abdominal trauma].

PURPOSE: To evaluate a modified algorithm in the diagnostic management of polytraumatized patients by using whole body multislice CT (MSCT) as primary diagnostic tool. MATERIAL AND METHODS: Between June 1999 and October 2000 532 polytraumatized patients were referred to the emergency department. 336 polytraumatized patients were primarily evaluated using whole body MSCT according to the "Innsbruck Emergency Algorithm." MSCT is performed immediately after cardiovascular stabilization of the patient. During the initial stabilization period free intraabdominal fluid is excluded or demonstrated by abdominal ultrasound. Time-consuming conventional radiographs are omitted with exception of an optimal chest X-ray. In patients with suspected or obvious arterial injuries or fractures the multislice-CT-dataset is used to perform 2D and 3D reconstructions in order to optimize visualization of additional skeletal and vascular injuries. RESULTS: By means of whole body MSCT it was possible to detect all injuries. The diagnostic advantage of whole body MSCT as compared to conventional X-ray was analyzed in 111 consecutive polytraumatized patients with an injury severity score (ISS) of 34.77. The early use of MSCT shortened the time for diagnostic work-up substantially (approximately 50%). CONCLUSION: Whole body multislice-CT used as primary diagnostic tool in the management of polytraumatized patients allows for a fast, accurate and comprehensive diagnostic work-up.

Abdominal Injuries↗
PubMed2002

Virtual endoscopy for planning neuro-endoscopic intraventricular surgery.

To evaluate the usefulness of virtual endoscopy (VE) in planning neuroendoscopic intraventricular surgeries, the technique was applied in 20 of 22 consecutive procedures. Thirteen endoscopic third ventriculostomies (ETV) in 12 patients, 3 endoscopic colloid cyst removals, 1 third ventricular arachnoidal cyst fenestration, 1 endoscopic ventricul-cysto-cisternostomy (suprasellar arachnoidal cyst), 1 endoscopic tumor biopsy, one third ventricular gross total tumor removal and 2 septostomies at the foramen of Monro due the septal occlusion were performed. Contrast medium-enhanced MR images (3DMPRAGE, Siemens, Germany) were semi-automatically segmented with a surface-rendering technique ("Navigator" software, General Electric Medical, Buc, France) to produce the virtual endoluminal views. Surgery was performed with cerebral ventriculoscopes by Wolf (Richard Wolf, Knittlingen, Germany). VE was feasible in all patients and the virtual endoscopic images were comparable with the real intraventricular views obtained by standard rod lens systems. After contrast medium administration intra- and paraventricular vessels such as the thalamocaudate vein, the septal veins, the basilar artery and its branches (distal BA complex) and the choroid plexus were identified on the virtual endoscopic images. In 8 patients, the additional anatomic information provided by VE profoundly influenced surgical planning. VE provides the neurosurgeon with additional morphological information supporting the planning process of neuroendoscopic intraventricular surgeries, contributing to the safety of the procedures.

Adolescent↗
PubMed2002

Efficacy and one year follow up of argon plasma coagulation therapy for ablation of Barrett's oesophagus: factors determining persistence and recurrence of Barrett's epithelium.

INTRODUCTION: Barrett's epithelium (BE) has malignant potential. Neither acid suppression nor antireflux surgery produce consistent or complete regression of the metaplastic epithelium. Endoscopic thermoablation with argon plasma coagulation (APC) offers a different approach but factors influencing its outcome have not been systematically examined. AIM: To assess the efficacy of APC and factors influencing initial and one year outcome. METHODS: Fifty patients, mean age 61.4 years, mean BE length 5.9 cm (range 3-19), underwent APC therapy at four weekly intervals while receiving proton pump inhibitor (PPI) therapy. BE margins were marked by India ink tattooing and extent was documented by grid drawings, photography, and 2 cm interval quadrantic jumbo biopsies. Twenty four hour ambulatory oesophageal pH studies were done while on PPIs before and after APC therapy, and Bilitec bilirubin monitoring after APC completion. RESULTS: A total of 68% of patients achieved >90% BE ablation after a median of four APC sessions. Persistent BE (>10% original BE area) was associated with longer initial BE length despite more APC sessions. Persistent acid and bile reflux on PPIs, although commoner in this group, were not significantly different from those successfully ablated. Fifteen of 34 patients (44%) with successful macroscopic clearance had buried glands, present in 8.3% of a total of 338 biopsies. At the one year follow up, only 32% of those with initial successful ablation showed no recurrence. BE recurred or increased in most with mean segment length increases of 1.1 cm and 1.6 cm, respectively, in patients with previous full ablation and those with persistent BE. The presence of buried glands did not predict BE recurrence. Patients who reduced their PPI dose had significantly greater BE recurrence. CONCLUSIONS: APC is most effective for shorter segment BE ablation but "buried" glands do occur. Recurrence of BE is common at one year, especially in those with initial persistent and/or long segment BE and those who reduce their PPI dose.

Adult↗
PubMed2002

Use of neuronavigation and electrophysiology in surgery of subcortically located lesions in the sensorimotor strip.

OBJECTIVES: Subcortical lesions in the sensorimotor strip are often considered to be inoperable. The purpose of this study was to evaluate the usefulness of a combined approach for surgery in this region, aided by a robotic neuronavigation system under electrophysiological control. METHODS: In a prospective study on 10 patients, space occupying lesions in the sensorimotor central area were removed using the Surgiscope robotic navigation system and the Nicolet Viking IV electrophysiological system. RESULTS: Precise tumour localisation with the neuronavigation system and the information on the patient's cortical motor distribution obtained by bipolar cortical stimulation led to postoperative improvement in motor function in all but one patient. Seven of the patients had focal, defined pathology (four metastases; two cavernoma; one aspergilloma). CONCLUSION: Due to the implementation of two recent technologies, surgery of lesions in the subcortical sensorimotor region can be performed with greater confidence.

Adult↗
PubMed2001

A simple and non-invasive vacuum mouthpiece-based head fixation system for high precision radiotherapy.

PURPOSE: To demonstrate why conventional non-invasive mouthpiece-based fixation has not achieved the expected accuracy and to suggest a solution of the problem. PATIENTS AND METHODS: The Vogele Bale Hohner (VBH) head holder is a non-invasive vacuum mouthpiece-based head fixation system. Feasibility and repositioning accuracy were evaluated by portal image analysis in 12 patients with cranial tumors intended for stereotactic procedures, fixated with the newest version (VBH HeadFix-ARC). RESULTS: Portal image analysis (8 patients evaluated in 2-D, 4 patients in 3-D) showed that even in routine external beam radiation therapy, treatment can be applied to within a mean 2-D and 3-D accuracy of under 2 mm (SD 0.92 mm and 1.2 mm, respectively) with cost and repositioning time per patient and patient comfort comparable to that of common thermoplastic masks. CONCLUSION: These preliminary results show that high repositioning accuracy does not rule out simple and quick application and patient comfort. Paramount, however, is tensionless repositioning via the vacuum mouthpiece.

Brain Neoplasms↗
PubMed2001

[Preoperative computerized tomography diagnosis of fractures of the tibial plateau].

Within the last decade computed tomography has become an important instrument for skeletal diagnosis. In this study the value of helical CT-scan was compared with plan X-rays and conventional tomography in 45 patients having sustained an intraarticular tibia plateau fracture. Between plan roentgenogramms and CT-scan the fracture classification according to the AO-classification was changed in 40% of all patients, in 39 cases the amount of impression or dislocation increased with a mean of 4.2 mm. Especially tiny fragments were better visible and therefore responsible for the shift of many B1 fractures to group B3. The difference between conventional tomography and computed tomography was less impressive, a change of fracture classification could be observed in only 6.7% of all cases.

Adult↗
PubMed2001

[Radiation exposure in single slice and multi-slice spiral CT (a phantom study)].

PURPOSE: The purpose of study was to compare patient dose applying singleslice- and multislice-spiral CT. METHODS: The examinations were performed with a singleslice-spiral CT (Highspeed Advantage; GE Medical Systems; Milwaukee, USA) and with a multislice CT systems (LightSpeed QX/i GE Medical Systems; Milwaukee, USA). For the determination of the radiation exposure (absorbed dose) a selection of most executed protocols (thorax-helical, abdomen-helical, petrous bone-axial, head-axial) were simulated using an Alderson Rando Phantom. The dose was determined by means of lithiumfluorid-thermoluminiscence dosimeters (TLD-GR 200). RESULTS: For thorax and abdomen protocols higher energy dose values could be found using a multislice CT. On the average the energy dose values were increased by 2.6 on an average in relation to single slice spiral CT. The energy dose values of the multisclice CT using head protocols could be reduced by 30% in relation to single slice spiral CT due to suitable parameter selections. The energy dose applying a petrous bone protocol resulted in an average increase by a factor 1.5 using a multislice CT. CONCLUSION: Using the new multislice CT technique protocol strategies must be optimized regarding the patient doses. Users can operate critically in the sense of the radiation protection only if they are aware of the occurring dose amounts to the patient.

Equipment Design↗
PubMed2001

Radial nerve palsy associated with humeral shaft fracture: evaluation with US--initial experience.

PURPOSE: To determine the feasibility of using ultrasonography (US) for evaluation of a radial nerve injury associated with humeral shaft fracture. MATERIALS AND METHODS: In a prospective study, 11 consecutive patients with sensorimotor radial deficiency after distal humeral fracture were evaluated with conventional radiography, US, electroneurography, and electromyography. Surgical repair of the fracture and nerve inspection were performed in five patients. The remaining six patients were successfully treated conservatively. The US appearance of the radial nerve was studied in 10 healthy volunteers and in the noninjured arm of the 11 patients for comparison. RESULTS: In five patients, US findings of a severely damaged radial nerve were confirmed at surgical nerve inspection. In one patient, the nerve was entrapped between fragments. One patient had a complete nerve dissection, one had a lacerated nerve from a loose compression plate, and one had a nerve riding on the edge of a bone fragment. In the fifth patient who underwent surgical inspection, the nerve was buried in the callus. In the six patients treated conservatively, US showed continuity of the nerve. CONCLUSION: US may be useful for accurate evaluation of the radial nerve in patients with nerve palsy associated with humeral shaft fracture.

Adult↗
PubMed2001

Psychophysical aspects in medical illumination techniques.

The relation between image and visual perception of the human eye is an important point in digital imaging systems. Research aims should therefore pay attention to psychophysical aspects. Optimising of digital imaging systems can only be reached if the important final steps in the diagnostic process--visual perception and signal detection--are taken into account.

Computer Terminals↗
PubMed2000

Diagnostic value of the DSM and ICD categories of psychosis: an evidence-based approach. UK700 Group.

BACKGROUND: It is generally assumed that the distinction between affective and non-affective psychosis occasioned by modern diagnostic criteria provides a useful symptomatic contrast. METHOD: In a sample of 708 patients with chronic psychosis, the distinction of lifetime DSM-III-R and ICD-10 diagnoses of affective versus non-affective psychosis was used as a diagnostic test to detect lifetime presence of depressive, manic, positive, negative and disorganisation symptoms. RESULTS: A manic or depressive affective diagnosis was a perfect test to diagnose the presence of manic and depressive symptoms, as evidenced by very high diagnostic likelihood ratios. However, this test result was based solely on the inclusion criterion that patients with affective psychosis must have affective symptoms (guaranteeing high specificity and high likelihood ratios), and ignored the fact that patients with non-affective psychosis also had high affective symptom scores (low sensitivity). Furthermore, a non-affective psychotic diagnosis was a very poor test to diagnose correctly the presence of positive, negative and disorganisation symptoms in comparison with an affective psychotic diagnosis. In general, the DSM-III-R categories performed somewhat better as a diagnostic test than those of ICD-10. CONCLUSION: The evidence for true diagnostic value of the distinction between affective and non-affective psychotic diagnoses is weak. Rather, the distinction appears to obscure natural overlap between the symptom dimensions of the different diagnostic categories.

Adolescent↗
PubMed2000

Virtual endoscopy for planning endoscopic third ventriculostomy procedures.

Virtual endoscopy was used to plan 10 endoscopic third ventriculostomy procedures in 9 patients suffering from occlusive hydrocephalus due to idiopathic aqueductal stenosis and tumors. The patients were 4 children (4-14 years, mean age: 9 years) and 5 adults (21-38 years, mean age: 29 years). The aim of the study was to preoperatively evaluate the individual intraventricular and vascular endoscopic anatomy at the floor of the third ventricle based on virtual endoscopic images. The virtual views were correlated with the real endoscopic images, intraoperatively obtained by a standard ventriculoscope (Wolf, Knittlingen, Germany) during endoscopic third ventriculostomy procedures. Contrast-medium-enhanced MR images (3D-MPRAGE; Siemens, Germany) were semiautomatically segmented with a surface-rendering technique ('Navigator' software; General Electric Medical, Buc, France) to produce the virtual endoluminal views. The virtual endoscopic images were comparable with the real intraoperative endoscopic view in 8 of 9 patients. Virtual endoscopy can display the position of the basilar artery, the posterior cerebral arteries and the posterior communicating arteries in their relationship to the mammillary bodies and the clivus. Preoperative virtual endoscopy planning can intraoperatively assist the neurosurgeon to find a safe location for third ventriculostomy.

Adolescent↗
PubMed2000

Changes in negative symptoms and the risk of tardive dyskinesia: a longitudinal study. UK700 Group.

OBJECTIVE: To examine whether the development of tardive dyskinesia (TD) is accompanied by a parallel process of worsening negative symptoms in a longitudinal study. METHOD: A sample of 708 psychotic patients were followed over a period of 2 years, using the Abnormal Involuntary Movement Scale and the Scale for the Assessment of Negative Symptoms (SANS). RESULTS: Of 361 individuals with no prior evidence of dyskinesia, 46 (13%) developed TD by year 2. Independent of the effects of male sex (odds ratio (OR)=2.18, 95% confidence interval: 1.00-4.74), age (OR per quartile group = 1.39, 95% CI: 1.01-1.90), duration of exposure to antipsychotic medication (OR = 2.35 per 8 months, 95% CI: 1.17-4.72) and average SANS score (OR per quartile group = 1.38, 95% CI: 0.99-1.93), worsening of negative symptoms over the 2 previous years was associated with TD onset (OR per quartile group = 1.46, 95% CI: 1.07-2.00). CONCLUSION: The development of TD is linked, independent of the effect of antipsychotics and older age, to an illness-related pathological process, characterized by worsening negative symptoms.

Adolescent↗
PubMed1999

Amisulpride vs. risperidone in the treatment of acute exacerbations of schizophrenia. Amisulpride study group.

Amisulpride, a substituted benzamide with high selectivity for dopamine D3 and D2 receptors, was compared with the antipsychotic risperidone in patients with acute exacerbations of schizophrenia. The study was double-blind and involved 228 patients allocated, after a 3-6-day wash-out period, to amisulpride 800 mg (n = 115) or risperidone 8 mg (n = 113) for 8 weeks. Both treatments produced a marked improvement in schizophrenic symptomatology. Decreases in mean BPRS total score were 17.7 +/- 14.9 for amisulpride and 15.2 +/- 13.9 for risperidone, and all of the individual factors on the BPRS showed a numerically greater improvement in the amisulpride than in the risperidone patients. Both treatments were equally effective against positive symptoms on the PANSS positive syndrome subscale; however, there was a trend in favor of greater improvement in negative symptoms assessed on the PANSS negative subscale in patients receiving amisulpride with a decrease of 6.9 +/- 7.5 vs. 5.3 +/- 6.6 for risperidone (P = 0.09). Both drugs demonstrated good safety profiles, and scores on neurological scales (SAS, AIMS, and BAS) did not increase during treatment. A comparable proportion of patients received antiparkinsonian medication, 30 and 23% in the amisulpride and risperidone groups, respectively (P = 0.21). Patients receiving risperidone experienced an increase in body weight, which was significantly greater than for amisulpride (P = 0.026).

Acute Disease↗