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Biomedical subjects

R Firsching

Publications and source records attributed to R Firsching.

At least 19 recordsLinked to original sources
PubMed2004

Early experiences with cervical disc prostheses.

UNLABELLED: The standard cervical disc surgery includes removal of the disc and fusion using an anterior approach. The loss of motion associated with fusion has prompted a search for other options. Early experiences and results after implantation of disc prostheses allowing for biomechanical motion of healthy discs are evaluated in this study. PATIENTS AND METHODS: 51 prostheses were implanted in 50 patients using an anterior approach. Follow-up ranged from one month to 14 months. RESULTS: The only significant complications were haemorrhages in two cases requiring surgical removal but otherwise all patients had an uneventful recovery. No infection or dislocation of the implants or formation of new spondylophytes have been noted yet. Resolution of pain and neurological disorders were excellent with a back-to-work rate of 80 % at three months after surgery. CONCLUSION: As the implantation of cervical disc prostheses carries no obvious risk higher than the risk of conventional anterior fusion, further analysis of its practicability and long-term outcome is recommended.

Adult↗
PubMed2003

Pineal epidermoid coinciding with pineocytoma.

Tumours of the pineal region are uncommon. We report on a 62-year-old male presenting with Parinaud's syndrome and aqueduct stenosis caused by a cystic tumour in the pineal region. During surgery, adjacent to the cystic tumour, a second smaller tumour was identified, which was clearly separate from the first tumour and from the pineal gland. Histological examination disclosed the cystic tumour as an epidermoid cyst, whereas the second tumour demonstrated histological and immunohistochemical features of a pineocytoma. The unique finding of two different types of tumours in the pineal region is evaluated with regard to the histogenesis of epidermoid cysts and pineocytomas.

Brain Neoplasms↗
PubMed2003

Pitfalls in surgery of meningeomas of the free tentorial edge.

Clinical experiences from 15 meningeomas located on the free edge of the tentorium are reported. Unexpected findings and complications found in five patients are presented in detail: Despite successful removal without postoperative morbidity after a presigmoid approach the preoperative loss of function of the ophthalmic nerve may cause increasing keratitis, which may result in blindness over the years after surgery. Before a presigmoid approach is performed, angiography or magnetic resonance angiography is advised, because the patient may have only one sigmoid sinus on the tumor side. An acute subdural hematoma as a complication of surgery may not only occur after, but also during surgery with the patient in the semi-sitting position. When a space occupying tumor of the tentorium is discovered, there may be an additional spinal one. If total removal of an extensive tumor of the free edge of the tentorium appears too hazardous, a two-stage strategy with a one year interval may lead to success.

Aged↗
PubMed2002

Practicability of magnetoencephalography-guided neuronavigation.

Magnetoencephalography (MEG) is a noninvasive option for localizing electroneurophysiological activity on the human cortex. The purpose of this study was to evaluate the practicability and reliability of MEG imaging integrated into a neuronavigation system to identify the sensorimotor cortex intraoperatively in patients with brain tumors in or near the central motor strip. It was performed prior to surgery in 30 patients with space-occupying lesions in or around the central region to localize the primary somatosensory cortex. These functional brain maps were superimposed on MR images obtained prior to surgery and transferred in the operating room for intraoperative functional neuronavigation. During surgery, the phase reversal technique identified a generator which coincided with the somatosensory cortex as displayed by the MEG-based functional neuronavigation system. Following surgery, the motor deficit improved in seven patients, was unchanged in five, and showed a slight transient deterioration in five. One patient suffered a deterioration of motor function with incomplete recovery. The MEG-based functional neuronavigation was found to be practicable and useful in finding a safe approach to tumors in or adjacent to the central region. The accuracy of MEG was concluded to be reliable as verified by the phase reversal technique.

Adult↗
PubMed2002

[Optimized image processing with modified preprocessing of image data sets of a transparent imaging plate by way of the lateral view of the cervical spine].

PURPOSE: To improve the diagnostic quality of lateral radiographs of the cervical spine by pre-processing the image data sets produced by a transparent imaging plate with both-side reading and to evaluate any possible impact on minimizing the number of additional radiographs and supplementary investigations. MATERIAL AND METHODS: One hundred lateral digital radiographs of the cervical spine were processed with two different methods: processing of each data set using the system-imminent parameters and using the manual mode. The difference between the two types of processing is the level of the latitude value. Hard copies of the processed images were judged by five radiologists and three neurosurgeons. The evaluation applied the image criteria score (ICS) without conventional reference images. RESULTS: In 99 % of the lateral radiographs of the cervical spine, all vertebral bodies could be completed delineated using the manual mode, but only 76 % oft the images processed by the system-imminent parameters showed all vertebral bodies. Thus, the manual mode enabled the evaluation of up to two additional more caudal vertebral bodies. The manual mode processing was significantly better concerning object size and processing artifacts. This optimized image processing and the resultant minimization of supplementary investigations was calculated to correspond to a theoretical dose reduction of about 50 %. CONCLUSION: The introduction of optimized organ programs for the upper and lower cervical spine based on the 12-bit data of the images should improve the evaluation of the lateral radiograph of the cervical spine without reducing the latitude value.

Cervical Vertebrae↗
PubMed2001

Present status of neurosurgical trauma in Germany.

Exact epidemiological data on head injury in Germany are limited and based on data from death certificates, the Federal Board of Statistics (Bundesamt für Statistik), small regional cohort studies, and health insurance. With a population of 82 million people there had been 279,029 head injuries admitted to hospital in Germany in 1996. The majority had the diagnosis. "concussion," which refers to completely reversible lesions. Head injury caused the deaths of 9415 patients in 1996, which amounts to a mortality of 11.5 per 100,000 inhabitants. At the same time there were 135 independent neurosurgical units, all of which had a computerized tomography scanner available. Of all fatal cases, however, 68.4% died before they reached a hospital. The exact cost is difficult to assess, because head injury causes more costs than only the hospital stay and rehabilitation.

Brain Injuries↗
PubMed2001

Classification of severe head injury based on magnetic resonance imaging.

OBJECT: In 1991 a new pioneering classification of severe head injuries had been proposed, based on CT findings. Unfortunately CT cannot visualise all lesions. Especially brain stem lesions may escape CT in spite of modern equipment, but may be demonstrated by MRI. The high incidence of CT negative but MRI positive posttraumatic brain stem lesions has already been demonstrated in a limited number of cases. A statistically significant evaluation is still missing. Therefore we have investigated a series of 102 comatose patients, in whom a statistical evaluation of MRI findings and their correlation with mortality and outcome of survivors was possible. PATIENTS AND METHODS: MRI was obtained within 8 days after servere head injury in 102 patients with a minimum of 24 hours of coma. The location of the lesions. identified by a neuroradiologist who was unaware of the clinical findings, was correlated with mortality, outcome of surviors and duration of coma. The correlation was analysed statistically. Follow-up ranged from 3 months to 3 years with a mean of 22 months. Four groups of lesions gave significant correlations: Grade I lesions were lesions of the hemispheres only; Grade II lesions were unilateral lesions of the brain stem at any level with or without supratentorial lesions; Grade III lesions were bilateral lesions of the mesencephalon with or without supratentorial lesions. Grade IV lesions were bilateral lesion of the pons with or without any of the foregoing lesions of lesser grades. RESULTS: Mortality increased from 14% in grade I lesions to 100% in grade IV lesions. The Glasgow outcome score differed significantly for each grade. The mean duration of coma increased from 3 days in grade I patients to 13 days in grade III. The correlations between the lesions grade I to IV with mortality, outcome of survivors and duration of coma were highly significant. CONCLUSION: The statistically significant correlations between the 4 groups of severe head injury patients, as identified by MRI, with mortality and outcome of survivors justify a new classification based on early MRI findings.

Adolescent↗
PubMed2001

Preliminary results of active specific immunization with modified tumor cell vaccine in glioblastoma multiforme.

OBJECT: Treatment for glioblastoma multiforme has failed to show any progress for decades. While specific immunization with tumor cells modified with Newcastle-Disease-Virus (NDV) has been reported successful in some extracerebral tumors, its effect on glioblastoma is unknown. We report on 11 patients, in whom this approach was analyzed. METHODS: A vaccine was produced from autologous tumor cell cultures of 11 patients with glioblastoma. After completed surgery and radiotherapy an intracutaneous vaccination was performed 4 times with a 2 week interval and finally after 3 months. Local reactions, general side effects and survival were monitored closely. RESULTS: The local reaction of the skin after injection of vaccine increased from 1.67 to 4.05 cm2 in 8 weeks. The skin reaction after parallel injection of inactivated, untreated tumor cells increased from 0.11 to 1.09 cm2. The median survival was 46 weeks (mean 60 weeks). No side effects were noted. CONCLUSION: Active specific immunization with NDV-modified glioblastoma cells produced a noticeable peripheral immune response. In this preliminary series survival of patients was not significantly longer after active specific immunization than after combined treatment of surgery, radiotherapy and chemotherapy. As there were no side effects, however, active specific immunization may be considered an alternative in the management of glioblastoma.

Adult↗
PubMed2001

Monitoring of the comatose patient.

Monitoring of comatose patients involves a close followup of clinical findings and a number of various techniques. These techniques may be differentiated in invasive and non invasive techniques. The benefit of these techniques is controversial as to their effect on the actual therapy of the comatose patient. The benefit of sedation beyond the point of what is required for adequate sedation is questioned, as it makes clinical observation useless. Since there is no evidence that any technical monitoring is as sensitive and reliable as clinical monitoring, the reliance on only technical monitoring needs to be discussed.

Coma↗
PubMed2001

Titanium or polymethylmethacrylate in cervical disc surgery? A prospective study.

In 200 patients with either isolated protrusion of disc or with spondylosis a cervical discectomy in one or two levels was performed from a ventral approach. In 100 patients the removed disc was replaced with an implant of polymethylmethacrylat (PMMA). In 100 patients interbodyfusion was done with a titanium cage. Both groups were analysed in a prospective study. Clinical outcome was assessed after surgery. Results were similar in terms of complications and clinical outcome. As the PMMA surgery took longer and the costs of titanium are higher, there is no marked advantage of one implant material over the other.

Bone Substitutes↗
PubMed2001

Ophthalmodynamometry: a reliable method for measuring intracranial pressure.

Under physiological conditions, the pressure in the central retinal vein is equal to or higher than the intracranial pressure (ICP) because the cerebrospinal fluid (CSF) passes the sheath of the optic nerve before draining into the cavernous sinus. The optic nerve sheath is where the ICP affects the retinal venous pressure. Ophthalmodynamometry (ODM) is a useful method for determining the central retinal artery pressure. While papilledema and a lack of venous pulsations are commonly used as a vague indication of the ICP, ODM may be advantageous for determining the pressure in the central retinal vein. Until now, however, the venous pressure has never been compared with the intracranial pressure. In the present study, the pressure in the central retinal vein was recorded in 31 patients while the ICP was simultaneously being recorded for various reasons. The results demonstrate a linear correlation (r = 0.968) between the pressure in the central retinal vein and the ICP. This correlation is of great practical value since until now, reliable intracranial pressure monitoring has only been possible by invasive means, by placing a probe either in the brain parenchyma or the ventricle. Ophthalmodynamometry is useful for momentary assessment of the ICP, can easily be repeated, and may be used whenever an elevated ICP is suspected in hydrocephalus, brain tumors and after head injury. However, it is not suitable for continuous ICP monitoring.

Adolescent↗
PubMed2000

[Ophthalmodynamometry. A reliable procedure for noninvasive determination of intracranial pressure].

BACKGROUND: Central vein pressure depends on intracranial pressure (ICP). Baurmann in 1925 therefore recommended measuring central vein pressure to determine ICP, but the accuracy of this method has not yet been verified. To test the method we measured venous outflow pressure (VOP) by noninvasive ophthalmodynamometry (ODM). METHODS AND MATERIALS: We studied 31 patients with suspected increased ICP. ICP was recorded continuously for a minimum of 24 h by intraventricular catheters, and ODM was performed during ICP measurement. The findings were compared with the results of conventional invasive ICP measurement. RESULTS: Pressure in the central retinal vein was highly correlated with ICP. CONCLUSION: Measuring VOP by ODM seems to be a reliable method for noninvasive recording of ICP. It is a useful screening test in all cases of presumed ICP elevation.

Adolescent↗
PubMed2000

MRI-findings after uncomplicated anterior cervical discectomy.

BACKGROUND: The anterior approach for cervical discectomy with methacrylate-implant involves manipulations on vertebral bodies and ligaments. Foreign materials like methacrylate and fibrin sponge are inserted. On postoperative MRI it may be difficult to differentiate pathological from "normal" findings caused by routine manipulations. METHOD: In this study 14 patients free of symptoms after anterior discectomy with methacrylate-implant were examined clinically and a MRI was performed on the 7th day after surgery and again after a 6 month follow-up. All patients had an uneventful recovery and no signs of inflammation after surgery. FINDINGS: Independent of the underlying pathology (e.g. soft or hard disc) 73% of the patients had a signal reduction within the vertebral bodies adjacent to the operated disc on T1-weighted spin-echo images on the 7th postoperative day. Signal intensities were normal after 6 months in all patients. Remarkable metal artifacts were present in one patient only. The methacrylate-implant could be identified as a hypo-intense structure on all sequences at any time without artifacts. In 80% of the cases a hyperintensity was found on T2-weighted images between the methacrylate-implant and the dura on the 7th postoperative day. A protrusion of the posterior ligament was present at the level of the operated disc on day 7 after surgery, which had resolved completely 6 months later. This may mimic residual disc tissue or osteophytes early after surgery. INTERPRETATION: It is very important to know this "normal" postoperative appearance of the cervical spine in order to avoid misinterpretations.

Cervical Vertebrae↗
PubMed2000

[Magnetic resonance imaging diagnosis of craniobasal cerebrospinal fluid fistulas by 3D-CISS sequence].

Recently, a Magnetic Resonance Imaging (MRI)-technique has been developed to diagnose the exact anatomical location of fistulas of the cerebrospinal fluid (CSF). This method is called 3D-constructive interference steady state-sequence (CISS) but it is not well known in clinical practice. Aim of the study was the evaluation of specificity and sensitivity of CISS-MRI. 12 patients with rhinoliquorrhea after head injury (n = 7) or skull base tumours (n = 5) were examined by CISS-MRI. The examinations were performed with a 1.5 T whole body MRI scanner in prone position and coronal plane sections. In cases of CSF leckage the sensitivity for detection of a CSF fistula was 100%. In comparison with intraoperative findings, specificity was 100%: in all cases, a dural lesion in anatomical correlation to MRI was detected. Further advantages of this method are its non-invasive character, no need for contrast application, no radiation exposure, and exact localisation of additional anatomical findings (brain herniation, brain contusions).

Adolescent↗
PubMed2000

Practicability of intraoperative microvascular Doppler sonography in aneurysm surgery.

Inadvertent narrowing of parent or branching vessels is one major cause of unfavorable outcome from aneurysm surgery. Intraoperative micro-Doppler sonography of arterial brain vessels during surgery for cerebral aneurysms of the anterior circulation was performed in 50 patients and compared retrospectively with 50 patients, who were operated upon without micro-Doppler sonography. Intraoperative micro-Doppler sonography demonstrated the need for repositioning of the clip in 12 instances. Outcome after surgery with micro-Doppler sonography appeared slightly better than without. Micro-Doppler sonography is concluded to be a practicable adjunct to routine aneurysm surgery.

Adult↗
PubMed2000

CD46 transgene expression in pig peripheral blood mononuclear cells does not alter their susceptibility to measles virus or their capacity to downregulate endogenous and transgenic CD46.

CD46 (or membrane cofactor protein) protects autologous cells from complement-mediated lysis and has been expressed as a transgene in pigs to overcome complement-mediated hyperacute rejection of porcine organs upon transplantation into primates. Since CD46 has been identified as a receptor for measles virus (MV), the susceptibility of CD46-transgenic (tg) pig peripheral blood mononuclear cells (PBMC) to infection with MV strains which do and do not use CD46 as receptor was investigated. Surprisingly, it was found that MV vaccine strains (e.g. Edmonston) bound to tg as well as non-tg pig PBMC. Phytohaemagglutinin-stimulated CD46-tg and non-tg pig PBMC were equally well infected with MV vaccine strains irrespective of CD46 expression. Upon infection, tg CD46 was downregulated from the cell surface. In contrast, the binding capacity for MV wild-type strains to pig and human PBMC was low, irrespective of CD46 expression. These MV strains did not infect tg or non-tg pig cells. Expression of endogenous pig CD46 was detected with polyclonal sera against human CD46. After infection of pig PBMC with MV strain Edmonston, endogenous pig CD46 was also downregulated. This suggests an interaction between MV Edmonston and pig CD46. However, polyclonal CD46 sera did not inhibit infection with MV Edmonston indicating that CD46 may not exclusively act as a receptor for MV on these cells. Interestingly, similar results were observed using human PBMC. Data suggest that CD46 downregulation after interaction with MV may also occur in porcine organs which express endogenous and/or human CD46 as a means of protection against complement-mediated damage.

Animals↗
PubMed2000

Venous opthalmodynamometry: a noninvasive method for assessment of intracranial pressure.

OBJECT: The goal of this study was to examine the potential use of ophthalmodynamometry in the noninvasive assessment of intracranial pressure (ICP). Under normal conditions, pressure within the central retinal vein is equal to or greater than ICP, because the central retinal vein basses through the optic nerve before it drains into the cavernous sinus. The optic nerve sheath is the place where ICP affects retinal venous pressure. Suction ophthalmodynamometry is an established method of investigation in ophthalmology to determine the pressure of the central retinal artery. Although observations of papilledema and lack of venous pulsations are commonly used to provide a vague assessment of ICP, ophthalmodynamometry may be used to determine the pressure of the central retinal vein. This venous pressure has never been compared with ICP. METHODS: In this study the pressure of the central retinal vein was recorded in 22 patients who underwent continuous simultaneous registration of ICP for various reasons, mainly for suspected hydrocephalus. A comparison of the two pressures was made. The results indicated a highly significant linear correlation between central retinal vein pressure and ICP. These results are of great practical value because up-to-date reliable ICP monitoring has only been possible by using invasive means, by placing a probe extradurally or subdurally into the brain parenchyma or a ventricle. CONCLUSIONS: Ophthalmodynamometry can be relevant for momentary assessment and is not suitable for continuous monitoring. However, this technique can easily be repeated and may be used whenever increased ICP is suspected in a patient suffering from hydrocephalus, brain tumors, or head injury.

Adolescent↗