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Biomedical subjects

F Bootz

Publications and source records attributed to F Bootz.

At least 73 records · Page 4Linked to original sources
PubMed1999

[MR-track pointer. A reusable device for localization during interventions].

PURPOSE: Development of an helpful instrument for a better planning and orientation during MR guided interventions. MATERIAL AND METHODS: We developed a reusable, sterilizable instrument that can be filled both with a solution of Gd-DTPA (1%) and with a sodium chloride solution (0.9%). The pointer has a diameter of 3 and 5 mm resp. and its length is 100-150 mm. The instrument can be combined with an interactive stereotactic tracking device. RESULTS: The MR-Track-Pointer can be fixed to the two handpieces of the integrated interactive tracking system without problems. The pointer can be seen both on T1w and T2w sequences inside and outside of the tissue. This new instrument can be interactively used for reliable planning the biopsy trajectory, planning craniotomies and identifying structures which are only visible on MR images. CONCLUSIONS: The MR-Track-Pointer is an ideal supplement for the integrated virtual tracking system. It permits a minimal invasive orientation and facilitates the exact localisation of suspect lesions in sensible regions during MR guided interventions, e.g. diagnostic biopsies and tumour resections.

Biopsy↗
PubMed1998

[Objective methods for simulated detection of unilateral deafness with special reference to DPOAE (distortion-product otoacoustic emissions) exemplified by a case report].

The simulation of unilateral deafness is very rare. Objective findings are of special interest if it happens. A patient with alleged deafness on the left-hand side due to commotio cerebri was treated in our hospital. Pure tone audiometry showed deafness on the left-hand side and normal hearing on the right-hand side. However, stapedius reflexes were found ipsilaterally left as well as contralaterally right, at 0.5 to 2 kHz with a stimulation of approximately 90 dB SPL. Transiently evoked otoacoustic emissions (TEOAE) and distortion-product otoacoustic emissions (DPOAE) were measured. The TEOAE had the same reproducibility but a very low response on both sides, such that inner ear function could not be evaluated. In comparison, the DP gram showed clear DP amplitudes over the whole frequency range on both sides. Nonphysiological DPs could be excluded by assessing the DP growth rate at three different frequencies. By means of brainstem electric response audiometry (BERA), with which the IV/V complex was detectable up to stimulation with 20 dB SPL clicks, and the Stenger test, a neural or central hearing loss could be excluded. Normal hearing on the left-hand side was thus confirmed. In cases of simulated deafness it is possible to prove a normal inner ear function by DPOAE. DPOAE therefore complements the list of potential audiological simulation tests.

Adult↗
PubMed1996

[Free transplanted, microvascular reanastomosed forearm flap for reconstruction of the mouth cavity and oropharynx. Clinical and morphologic findings with special reference to reinnervation].

It remains a controversial question whether or not the anastomosis of sensory nerves is necessary in free transplants of microvascularly reanastomosed radial forearm flaps in the oral cavity and oropharynx. Some authors perform this routinely because they expect fewer complications in a skin with a sensory nerve supply. We carried out clinical and morphological examinations in 20 patients in order to determine the sensory innervation of the transplanted tissue. All patients received free transplants of microvasculary reanastomosed radial forearm flaps during a tumor operation in the oral cavity or oropharynx. Postoperative wound healing proceeded without complications in all but three cases, but these disturbances were insufficient to explain any deficit in sensation in the operated areas. Following surgery, sensation was determined clinically by two-point discrimination. Morphological studies of 20 flap biopsies using conventional colored light microscopy demonstrated nerve fibers in 14 of the biopsies. Immunohistochemical investigations also showed the presence of small nerve fibers by proving S-100 positive Schwann cells. We could not find a correlation between the demonstration of nerve fibers and the use of radiation (or an increased radiation dosage) following surgery. These findings suggest that nerve regeneration was completed just before the 6th postoperative month, which was the earliest time recorded in this study. Perivascular (vegetative) nerves showed a delayed regeneration and could be demonstrated only 36 months after operation. Histological investigations of the transplanted tissue showed a decrease in keratin with a partial increase in parakeratosis, a loss of skin structures and nearly always chronic inflammation. Our findings verify that a sensory innervation is possible in free transplanted radial forearm flaps by the regeneration of nerves coming from the transplantation bed and/or adjacent (oral) mucosa. This leads to a sensation comparable to that of healthy mucosa. These findings also indicate that there is no need for the anastomosis of sensory nerves during transplant surgery.

Adult↗
PubMed1995

Repair of anterior base of skull with free latissimus dorsi flap.

After craniofacial resection for ethmoid and nasal cancer the resulting defect in the anterior base of skull often is a problem because of liquorrhoea, followed by meningitis and brain herniation. Two approaches were used for surgery of ethmoid and nasal cancer involving the anterior base of skull-the transfrontal and the transethmoidal. The neurosurgeon performs the transfrontal approach, an additional lateral rhinotomy and ethmoidectomy is made by the ENT-surgeon. Seven patients underwent radical operation with immediate repair of the skull base defect performed in four and delayed repair in three cases with a microvascular latissimus dorsi muscle flap. The flap was tailored as a pure muscle transplant if only the base of skull had to be repaired and the surgical cavity had to be obliterated. In three cases a skin paddle was left on the muscle to perform closure of the orbit and of the hard palate. The aim of reconstruction is a good functional and cosmetic result and reduction of postoperative problems-such as brain herniation, CSF-leakage and meningitis-by obliteration of surgical cavities. Furthermore crusting of large cavities and disorders of phonation are reduced. The disadvantage of limited direct postoperative tumour control by nasal endoscopy however is justified by an increase of quality of life.

Adult↗
PubMed1995

Free latissimus dorsi flap for reconstruction of the anterior base of the skull.

Defects resulting after resection of malignant tumors of the paranasal sinuses involving the anterior base of the skull need an adequate closure. In addition to such avital tissue as fascia lata, fat, or ceramics, in recent years we used free muscle flaps from the latissimus dorsi for reconstruction. We performed this reconstructive method in seven patients after radical tumor ##. The operation was performed in cooperation with the neurosurgeon. In three cases a transfrontal in combination with a transfacial approach was used and in four cases only a transfacial approach was chosen. The flap was tailored as a pure muscle transplant if only the base of the skull had to be repaired and the surgical cavity had to be obhiterated. In three cases a skin paddle was left on the muscle to perform a closure of the orbit and the hard palate. In four patients we performed primary reconstruction, in three cases secondary reconstruction, which was necessary because cerebrospinal fluid (CSF) leakage occurred after primary reconstruction with avital tissue in addition to insufficient pericranial flap. None of the patients with primary reconstruction developed CSF leakage. There was no free flap failure. The aim of this reconstruction is a safe closure of skull base defects to prevent infection, meningitis, brain abscess, and brain herniation.

Journal Article↗
PubMed1995

[Tinnitus models for use in tinnitus counselling therapy of chronic tinnitus patients].

Tinnitus models are an integral part of tinnitus counselling. In cases with compensated tinnitus, counselling represents the only therapeutic measure necessary. In contrast, patients with uncompensated tinnitus require further therapy in the form of medication, tinnitus-maskers or psychotherapy. Sound processing along the peripheral and central auditory pathways is achieved by functional loops that direct mechanical, electrical or chemical information to various points in the pathway. Minor damage to a loop can cause destabilization of this finely balanced system and can induce tinnitus. Current peripheral tinnitus models are reviewed and discussed with respect to in vitro data from isolated outer hair cells of the guinea pig cochlea. Audiological findings of a patient with central tinnitus after brainstem surgery are discussed in view of central tinnitus models. Specific models for common hearing disorders, such as tinnitus with normal hearing, noise trauma, sudden hearing loss, toxic cochlear lesions, presbyacusis, acoustic neurinoma and Menière's disease are presented for the ENT-surgeon involved with tinnitus-counselling.

Adult↗
PubMed1994

Influence of static middle ear pressure on transiently evoked otoacoustic emissions and distortion products.

Otoacoustic emissions (OAE) are influenced in their amplitude and frequency spectra by the middle ear. The effects of changes in the middle ear transmission mechanisms on transiently evoked OAE (TEOAE) and distortion product emissions (DPOAE) were investigated as a function of static ear canal pressure in 25 normal-hearing test persons aged 18-35 years. The ear canal pressure was varied stepwise between positive and negative values of 200 daPa. TEOAE and DPOAE amplitudes were attenuated significantly with changes of the static ear canal pressure, with greatest changes at low frequencies (< 2 kHz). The alterations of OAE amplitude were slightly dependent on the polarity of the pressure, with positive pressure producing a greater attenuation (0.6 dB). The results demonstrate that changes in middle ear impedance can cause a misinterpretation of OAE. To avoid this problem, tympanometry should always precede OAE measurements. Alternatively, both methods can be combined using one acoustic probe, so that the emissions can be evoked at the peak of middle ear compliance.

Acoustic Impedance Tests↗
PubMed1994

[Microvascular tissue transplantation in plastic reconstruction of the external head-neck area].

Free tissue transfer is under certain circumstances an ideal reconstructive method for skin and soft tissue defects of the head and neck region. These are multilayer, large defects, recurrences after previous reconstructive methods, in cases of aesthetic disturbances due to local flaps, in difficult reconstructive areas due to chronic infection and radiotherapy and if local tissue is not available. From 1987 to 1993 we performed 30 reconstructions of the surface of the head and neck region with free flaps, mainly the forearm flap and the scapular flap. But also the latissimus dorsi flap and in one case the rectus abdominis flap were used. There was no flap failure. In only one case of a forearm flap we saw a delayed healing of the donor defect. There was no functional impairment of the donor defect. All cosmetical results were acceptable. Flaps from the trunk mainly showed considerable differences in colour and texture to the surrounding skin.

Adult↗