Biomedical subjects

H F Reinhardt

Publications and source records attributed to H F Reinhardt.

At least 19 recordsLinked to original sources

PubMed1996

Computer assisted brain surgery for small lesions in the central sensorimotor region.

The capacity of a new optical navigation device is demonstrated by six microsurgical procedures for small subcortical lesions within the central sensorimotor strip. This small series is aimed at less invasive resection in this functionally critical region, independently of primary diagnosis and outcome. Guided by high resolution CT imaging data five brain tumours and one cavernous angioma was selectively located and most sparingly removed without additional sensorimotor deficit. In two cases improvement of a pre-operative paresis was observed immediately after surgery. Thanks to light-weight freehand pointing instruments and a ranging accuracy of +/- 1 mm, damage to functionally important brain areas and vessels was avoided by using uncommonly oblique, e.g., transsulcal ways of access which would hardly have been possible even with guidance by conventional stereotaxy. The demanding systematic cortical stimulation of the precentral gyrus applied in three cases was only sensitive in infiltrating tumours-e.g., low grade astrocytomas-where for want of adjuvant therapy it was essential to proceed to the extreme limits of resection. In general, precise anatomical localisation by computer aided surgery (CAS) is sufficient in small central lesions which guarantees minimally invasive surgery. The potential of this new, soon commercially available optical navigation system in (neuro) surgery, quality control and teaching is discussed.

Adult↗

PubMed1995

Microstereometrically guided cortical stimulation for the intraoperative identification of the central motor strip.

A rangable stimulation tool based on the sonar microstereometric system has been developed for the intraoperative identification of the central motor strip. The elicited motor evoked potentials (MEPs) were recorded with surface electrodes and displayed together with the corresponding stereometric coordinates of the stimulation site. MEP data were overlaid in 'real time' on preoperatively scanned CT images on a computer screen. The system has been used during open microsurgical procedures in 6 patients with small tumors near the central motor strip or related 'eloquent' areas. Three operations have been performed under local anesthesia, 3 under general anesthesia. It was possible to operate on tumors located closely to functionalal relevant areas of the brain not only stereotactically, but also with function guidance.

Adult↗

PubMed1994

Ranging accuracy test of the sonic microstereometric system.

We have recently introduced a new type of ultrasonic-based, three-dimensional ranging system for the localization of small handheld surgical tools to be used during operation in open stereotactic brain surgery. This targeting system has now been extensively laboratory tested during thousands of measuring cycles with a CNC-based measuring table. The typical accuracy found in a single direction was 0.4 mm and better. The accuracy vector in space was 0.897 mm (n = 2312). The test-retest accuracy was typically 0.4 mm. With the given accuracy, the system is suitable for all ranging tasks in open stereotactically guided microsurgery.

Brain Diseases↗

PubMed1993

Sonic stereometry in microsurgical procedures for deep-seated brain tumors and vascular malformations.

A frameless computerized navigating system was successfully employed in 20 cases of open microsurgical operations on deep-seated brain tumors and vascular malformations. Localization in space was made by measuring the traveling time of sonic waves (24 kHz) in air. This allowed the construction of mechanically simple, lightweight freehand targeting instruments. The tips can be localized with a measuring accuracy of +/- 1 mm intracranially on the basis of computed tomographic scans. This thoroughly redesigned sonic stereometrical device is being optimized for everyday use; magnetic resonance imaging, digital substraction angiography, and other diagnostic modalities will be implemented. Some perspectives on "computer-aided (neuro)surgery" are discussed.

Adolescent↗

PubMed1993

Stereo-microvision. Development of an opto-electronic operating microscope.

A novel opto-electronic operating microscope has been designed and clinically tested. It consists of a small camera microscope, a central electronic unit, and a stereoscopic video monitor. Advanced miniaturization permitted ergonomics superior to those of conventional optomechanical microscopes. Electronic imaging facilitates coupling to an ultrasound navigation system which enables the neurosurgeon to verify the location of the focus in real time, correlated with CT and MRI pictures. A fully computerized, digital operating microscope will now be developed based on this prototype.

Brain Diseases↗

PubMed1991

[Microsurgical removal of deep vascular malformations using sonar-stereometry].

The advantages of a new, dynamic sonar technology in open stereotactic microsurgery are demonstrated by means of three surgical procedures for deep-seated vascular malformations that are not easy of access. With this method, targets can be aimed at without using rigid, obstructive pointing devices as in conventional stereotaxy. On the contrary, it is possible to take advantage of preformed anatomical spaces reaching the lesion most carefully by means of light-weight, free-hand on-target instruments. The spatial information, correlated with a CT data set, is displayed in real time with an accuracy of +/- 1 mm. Additional image data from MR and digital angiography can be used interactively.

Adult↗

PubMed1990

[From stone trephine to robots, 5000 years of neurosurgery].

Only a century has elapsed since the first serious surgical interventions on the human brain were undertaken; man has however sought to understand its structure and function for several thousand years in order to reach therapeutic consequences. A few highlights of brain research and neurosurgery from the neolithic to current times are described along with the prevailing views and technologies. Parallels are drawn with examples from clock making. An outlook to computer aided surgery (CAS) combining modern imaging techniques with data processing and technical operative innovation is given.

Europe↗

PubMed1990

[CT/MRI correlated stereometry with ultrasound in brain surgery].

Today the accuracy of medical imaging systems lies between +/- 0.5 mm (CT) and +/- 2.5 mm (MRI). In neurosurgery the overall uncertainty may reach the dimension centimetres. A non-tactile ultrasonic measurement system is described that allows three-dimensional measurement with a theoretical accuracy of +/- 0.1 mm in a frequency range between 50 and 70 kHz. In practice the accuracy is better than +/- 1 mm with a repetition rate of 10 per second for the x,y,z-data sets.

Angiography, Digital Subtraction↗

PubMed1990

Interactive sonar-operated device for stereotactic and open surgery.

An accuracy of +/- 1 mm in surgical localization of brain targets was reliably attained with a new sonar-operated system, provided that air turbulence was minimized. Since a conventional frame construction with coordinate settings has been disposed of, apart from a halo ring head holder, free access to the operating site is guaranteed. Using offset probes, measurements in depth can be realized with a relatively simple hardware arrangement. A small, 'floating' locator probe can be attached to all kinds of surgical instruments; its spatial position is computed in real time and immediately referred to computed tomography/magnetic resonance imaging scans. Although this work is still in progress, promising applications both in stereotactic and in open surgery are envisaged.

Angiography, Digital Subtraction↗

PubMed1989

CT-guided "real time" stereotaxy.

Starting from a previously developed 3-D digitizer for a CT correlated topographic orientation during open brain surgery a computerized targeting device was constructed specially designed for stereotaxy. CT and later MRI data are transferred to an IBM compatible personal computer. The spatial information is registered by a multi-axis measuring arm. Advantages and future development of computerized stereotaxy are discussed.

Biopsy, Needle↗

PubMed1984

[Epidural hematoma before and following introduction of cerebral computer tomography].

An analysis of 120 extradural hematomas 7 years before and after introduction of computerized axial tomography (CT) showed that application of this new method resulted in considerable progress in diagnostic accuracy and a small saving of time. It was, however, prognostically decisive that the physician at the site of the accident or in the first-aid unit recognized the risk of imminent bleeding and immediately arranged for transport to the neurosurgical centre. The significance of the "typical" early symptoms of extradural hematomas was analysed. The importance of the exposed temporoparietal skull fracture, of careful neurological supervision and generous diagnostic use of the CT-scan is stressed.

Adolescent↗

PubMed1984

[Ultrasonic resection of brain tumors].

With the CUSA Ultrasonic Aspirator even consistent tumors can be removed with a minimum of tissue traction and almost entirely sparing the adjacent neural and vascular structures. The hand guided titanium tip oscillates at 23 kc and disintegrates the pathological tissue aspirating it continuously through a central channel. Particularly in neurosurgery, where in many instances resection has to be carried out transtumorally this instrument has proved to be of great help. Three cases of large brain tumors are presented in which the CUSA technique allowed an easy and rapid removal of the neoformation with a minimum of blood loss.

Aged↗

PubMed1983

[Results of the surgical treatment of cervical disk hernia and myelopathy with dorsal approach].

Between 1978 and 1981 68 patients underwent posterior surgery on the cervical spine at the Neurosurgical Clinic of Basle. In 24 patients the radicular compression syndrome was caused by a soft disc herniation and in 25 patients by degenerative changes of the cervical spine (hard discs). In 19 patients a cervical myelopathy was caused by a narrowing of the spinal canal. After 1-4 years follow-up the results were excellent or good in more than 90% in soft discs, 80% in hard discs and less than 40% in spinal canal stenosis. The advantages and inconveniences of the different approaches and operative methods are discussed.

Adult↗

PubMed1980