Biomedical subjects

M Tschabitscher

Publications and source records attributed to M Tschabitscher.

At least 19 recordsLinked to original sources

PubMed1999

Two-port endoscopy of the middle ear: endoscopic anatomy.

OBJECTIVES: To shed light on the endoscopic anatomy of the middle ear seen on 2-port endoscopy and to describe potential clinical applications. DESIGN: Anatomical structures were visualized by transmeatal or transtympanic rigid scopes of different angles and by a flexible scope in the eustachian tube. This arrangement ensured reciprocal guidance of the scopes and provided access to regions not seen otherwise. SETTING: The Department of Anatomy 1, University of Vienna, Vienna, Austria. MATERIALS: Forty tympanic cavities obtained from cadaver skulls without prior fixation were examined. Specimens did not show any abnormalities and were chosen without regard to age or sex. RESULTS: Depending on the angle of view, rigid transmeatal or transtympanic endoscopes provided a full view of the entire tympanic cavity except for the epitympanum, access to which was barred by the incudomallear joint, the mallear folds, and the tympanic chord, but the epitympanum was well visualized through the flexible, steerable, transtubal scope. CONCLUSIONS: Two-port endoscopy of the middle ear offers a full view of all structures in the tympanic cavity. The atraumatic transtubal approach to the tympanic cavity enhances the safety of transmeatal interventions and facilitates postoperative follow-up.

Cadaver↗

PubMed1998

The lumbrical muscle flap: anatomic study and clinical application.

This article describes the anatomy and clinical application of the lumbrical muscle flap. Anatomic and radiologic studies were performed in 20 fresh human cadaver hands injected with latex-lead-oxide solution. Only the 2 radial lumbrical muscles were found suitable for flap transposition. The vascular supply of the first and second lumbrical muscles is from branches originating in the superficial palmar arch and from the common palmar digital artery, respectively. The dominant branches invariably enter the muscle bellies at the junction of their proximal and middle thirds. Pedicled on these vessels, the lumbrical muscles can be transposed to reach the entire palm, up to the wrist flexion crease. The clinical use of the first and second lumbrical muscle flaps in 2 patients demonstrated the value of these flaps for coverage of the median nerve and its palmar branches.

Cadaver↗

PubMed1998

Anatomic position of the asterion.

OBJECTIVE: The asterion is defined as the junction of the lambdoid, parietomastoid, and occipitomastoid sutures. The asterion has been used as a landmark in lateral approaches to the posterior fossa. However, its reliability as a landmark comes into question considering the apparent variability of its position. This study was performed to determine the reliability of the asterion as a surgical landmark. METHODS: One hundred dried skulls were obtained for study. A 2-mm drill hole was placed at the asterion on each side. The position of the drill hole on the inner surface of the skull was next determined and recorded. RESULTS: The asterion was located over the posterior fossa dura in 32% on the right and 25% on the left. Its position was over the transverse or sigmoid sinus complex in 61% on the right and 66% on the left. The landmark was located above the transverse-sigmoid sinus complex in 7% on the right and 9% on the left. CONCLUSIONS: The asterion is not a strictly reliable landmark in terms of locating the underlying posterior fossa dura. Its location is very often directly over the transverse-sigmoid sinus complex. Burr holes placed at the asterion may often open the bone directly over the sinus, leading to potential damage.

Anatomy, Artistic↗

PubMed1997

Epicardial branches of the coronary arteries and their distribution in the rabbit heart: the rabbit heart as a model of regional ischemia.

BACKGROUND: The rabbit heart has been frequently used to study regional ischemia, but there is hardly any detailed information on the epicardial branching of the coronary arteries. Therefore, we wanted to determine whether there is a constant branching pattern and how comparable this pattern is with the human heart. METHODS: We investigated epicardial branching of the coronary arteries in 30 adult rabbit hearts. For vessel visualisation, we used injections of Technovit, followed by corrosion. RESULTS: We found that there is not one constant pattern but rather a bifurcation or a trifurcation of the arteria coronaria sinistra (15 of 15 hearts). The left coronary artery is always the dominant artery; a vessel comparable to the human ramus interventricularis anterior is rarely found in the bifurcation type. The ramus circumflexus is a constant but minor branch of the posterior or posterolateral division and does not originate directly from the main stem of the left coronary artery, as it does in humans. As a consequence, ligation of the left ramus interventricularis anterior leads to severe ischemic injury only where trifurcation exists (50% of our population). A ligation of the ramus circumflexus proximal to its origin produces a large posterolateral infarction in the bifurcation type (50% of our population). CONCLUSIONS: Because a defined ischemic area is difficult to reproduce under these anatomical conditions, the rabbit heart may be a model only for regional ischemia if the investigator is knowledgeable about the distributions of the coronary arteries.

Animals↗

PubMed1997

The course of the prevertebral segment of the vertebral artery: anatomy and clinical significance.

BACKGROUND: The so called "pretransverse or prevertebral segment" of the vertebral artery is defined from its origin at the subclavian artery to its entry into the respective transverse foramen. In surgery, angiography, and in all noninvasive procedures it is of great importance to know the exact details of the course and the origin of this segment of the vessel as well as in which percentages real abnormalities can be found. METHODS: The VI segment of the vertebral artery was investigated both in anatomic preparations and clinical studies. A total of 402 vertebral arteries were evaluated (70 anatomic preparations in different forms, 181 patients, 95 angiographies of the aortic arch, and 86 color coded doppler sonographies). RESULTS: A contorted course was found in 157 (39%) cases. The plane of tortuosities demonstrated by the respective vessels was found to be horizontal in 40 (44.9%) cases, sagittal in 30 (33.7%) cases, and frontal in 19 (21.4%) cases. In 51 (32.5%) cases the contorted pathway was on the right side, and in 106 (68%) cases, on the left. A hypoplasia was found in 16 (10%) cases--11 (4.8%) right and 5 (2.2%) left. We further differentiated the convexity lying either medially or laterally in the transverse or frontal plane, or oriented dorsally or ventral in the sagittal plane. The exact location of the origin of the artery on the circumference of the subclavian artery (47% cranial, 44% dorsal, 3% ventral, 6% caudal) and also the average values of length and diameter are described. No significant differences between tortuous and nontortuous vessels were found with respect to length and diameter. A real abnormality of the origin of the vertebral artery was found in 8 (3.5%) cases. CONCLUSIONS: The described morphologic variations and frequencies of the VI segment of the vertebral artery have clinical applications in a wide field of pathologies in that region. To know about these findings seems to be very important not only in diagnosis (angiography, color coded doppler sonography) but also in their surgical and endovascular treatment.

Aorta, Thoracic↗

PubMed1997

Scarpa's fascia flap: anatomic studies and clinical application.

Fascia and fascia-subcutaneous flaps are thin, pliable, and well-vascularized tissue with aesthetic and functional advantages, particularly for the extremities and in the head and neck region. Although various donor sites have been used for these flaps, there is an occurrence of unsatisfactory donor-site defects that are often complicated by conspicuous, widened scars or alopecia. In addition, flap elevation is sometimes prolonged because of the demanding operative procedures as well as the impossibility of a two-team approach. In this anatomic and clinical study we present a new fascial flap that results in a minimal donor-site defect and a short and easy operative procedure. Scarpa's fascia, which can be used as both a free and a pedicled flap, is a well-defined single membranous sheet within the subcutaneous tissue layer at the lower abdominal wall. We studied its distribution, structure, and vascular supply in 27 fresh cadaver specimens. In addition, computed tomographic (CT) and ultrasound studies were performed in 13 healthy volunteers and in 3 cadavers before and after injection of diluted contrast material in the superficial epigastric artery. Finally, histologic examinations were done with hematoxylin and eosin or with reticulum and elastin. Our studies showed that Scarpa's fascia provides a thin, pliable, and well-vascularized flap pedicled on the superficial epigastric artery. After successful application of the Scarpa's fascia flap as a free flap in 3 patients and as a pedicled option in 1 patient, we can recommend this flap as a valuable tool for the reconstructive surgeon.

Abdominal Muscles↗

PubMed1997

The vertically based deep fascia turnover flap of the leg: anatomic studies and clinical applications.

Although fasciocutaneous turnover flaps are a simple and fast method for covering soft-tissue defects of the lower leg, many reconstructive surgeons have their doubts about them. They revolve around the lack of criteria for safely designing these random-pattern flaps and around the risk of donor site problems. A vertically based deep fascia turnover flap with a paratibial or parafibular pedicle is presented. Anatomic studies of 36 injected lower limbs showed the deep fascia to be supplied by a mean of 61 vessels. As musculofascial, septofascial, and periosteofascial branches, these contribute to a richly anastomosing vascular network within the deep fascia. Along the deep transverse septum at the medial tibial border, the anterior and posterior peroneal septa, and between the anterior tibial and extensor muscles, the fascia is supplied by segmental vessels in a clearly defined arrangement. Pedicled on these vessels, the deep fascia is a useful candidate tissue for transversely oriented turnover flaps. These are particularly well suited for covering pretibial or prefibular soft-tissue defects. Unlike adipofascial turnover flaps, the transversely oriented deep fascia turnover flap keeps its subcutaneous layer with its intact vascular plexus so that the overlying skin is adequately perfused even in patients with sizable flaps or an extremely thin skin. Clinical experience with the vertically based paratibial or parafibular deep fascia turnover flap in six patients confirmed its usefulness for covering small to medium-sized soft tissue defects of the lower leg.

Adult↗

PubMed1996

Endoscopic carpal tunnel release using a single-portal system.

In this prospective clinical study, we present our experience with a new single portal carpal tunnel release kit. The safety and efficacy of this new device was assessed and compared with a consecutive control group treated with conventional open carpal tunnel release. 126 patients were enrolled in this study, 64 of them were treated endoscopically (group 1) and 62 by open release of the carpal ligament (group 2). Follow-ups were conducted at 1, 3, 6, 12 and 24 weeks postoperatively. A serious intraoperative complication in group 1 was a transection injury of a branch of the superficial palmar arch. No intraoperative complications were noted in group 2. Postoperative evaluation revealed significantly less scar tenderness in group 1 at 1 week (P < 0.001), 3 weeks (P < 0.001) and 24 weeks (P < 0.05) compared to group 2. Functional status at 1 week was significantly (P < 0.05) better in group 1 than in group 2 but not at later times. Grip strength at 1 week (P < 0.001), 3 weeks (P < 0.05) and 12 weeks (P < 0.05), and pinch strength at 3 weeks (P < 0.001) were significantly higher in group 1. No significant differences between the groups were obtained regarding postoperative symptom severity. The new device provides a reliable tool for single portal carpal tunnel release, although the risk of inadvertent damage to the neurovascular structures always remains a possibility with the endoscopic carpal tunnel technique.

Activities of Daily Living↗

PubMed1996

Endoscopic exploration of the IVth ventricle.

Regarding to the upcoming techniques in neuroendoscopy the IVth ventricle was examined. First in a series of 30 fresh and fixed anatomical specimens-the vessels injected with LATEX-the fourth ventricle was investigated endoscopically. There are three possibilities to reach the IVth ventricle: coming from the IIIrd ventricle via the aqueductus cerebri, using the basal cisterns through the apertura lateralis Luschkae and coming via the cerebellomedullar cistern through the foramen of Magendi. Using different kinds of endoscopes (rigid, flexible and steerable flexible)-diameter ranging from 5 to 9 french-with different optical systems (0 degree, 5 degrees, 30 degrees, 75 degrees) and different light sources (Halogen, Xenon) the anatomical details seen under the endoscope and the topographical landmarks of the approaches were investigated, presented and discussed. Based on the experience at the end of the cadaver work a short comment on which kind of equipment seems the best was given. A series of 14 clinical cases was presented as the second part of the study (7 cases with a tumor in the IVth ventricle-2 metastasis, 3 gliotic tumors, 1 ependymoma, 1 medulloblastoma, 3 patients with an occluded aqueduct because of meningo-ventriculitis and 4 patients with cystic malformations). The neuroendoscopic approaches, the neuroanatomical details relevant for surgery and the clinical data will be given and discussed. In general no intraoperative or postoperative complications were seen. In conclusion our experience from the theoretical neuroanatomical and the clinical part as well as the advantages and disadvantages from the different kind of endoscopes and approaches are discussed.

Adult↗

PubMed1996

Formaldehyde and phenol exposure during an anatomy dissection course: a possible source of IgE-mediated sensitization?

The sensitizing potency of formaldehyde and phenol exposure during 4 weeks of an anatomy dissection course was assessed in 45 medical students. Specific IgE against formaldehyde by RAST and by ELISA and specific IgE against phenol by ELISA were assessed before and after the course. At the start of the course, symptoms, type I allergy, respiratory diseases, and smoking habits were noted. At the end of the course, only symptoms experienced during the dissection lessons were assessed. Indoor formaldehyde levels were measured continuously. The mean indoor formaldehyde level was 0.124 +/- 0.05 ppm, with a minimum of 0.059 ppm and a maximum of 0.219 ppm. Specific IgE against formaldehyde or phenol was found in none of the subjects at the beginning of the course, and no student showed specific IgE against formaldehyde or phenol after the course. Assessment of primarily irritant symptoms during the lesson revealed itch and paraesthesia of hands in 33/45 students (P < 0.00005), headache in 15/45 students, burning eyes in 13/45 students (P < 0.02), dizziness in 8/45 students (P < 0.008), sneezing in 4/45 students, epistaxis in 2/45 students, and shortness of breath in 1/45 students. According to our data, 1-month exposure to formaldehyde and phenol during an anatomy dissection course does not induce specific IgE against formaldehyde or phenol.

Adolescent↗

PubMed1996

Surface and superficial surgical anatomy of the posterolateral cranial base: significance for surgical planning and approach.

We have performed an anatomic study, 15 using fixed cadaveric preparations, with the goal of identifying surface landmarks that will reliably locate the underlying transverse and sigmoid sinus complex. Simple morphometric relationships were first determined on both sides of each specimen to yield 30 sides measured. The following relationships were determined: 1) zygoma root-asterion, 2) asterion-mastoid tip, 3) zygoma root-suprameatal spine (Henle's spine), 4) asterion-suprameatal spine, 5) mastoid tip-suprameatal spine. The relationship of the asterion to the transverse-sigmoid junction was determined by bone removal. Also, the distances from the asterion to the sigmoid sinus-superior petrosal sinus junction and the superior margin of the transverse sinus were studied. Surface and marks were found to have definitive relationships to underlying anatomic substrates in all specimens studied. The critical relationships that were concluded from this study can be described in terms of two easily identified lines between bony surface structures. A line drawn from the zygoma root to the inion, i.e., the superior nuchal line, reliably located the rostrocaudal level of the transverse sinus in all specimens. Although the asterion did not consistently fall on this line, the transverse-sigmoid junction could reliably be placed at the anteroposterior level of the asterion. Further, a line drawn from the squamosal-parietomastoid suture junction to the mastoid tip reliably defined the axis of the sigmoid sinus through the mastoid. We also found that the junction of the squamosal and parietomastoid sutures lay over the anterior border of the upper curve of the sigmoid sinus. The anterior portion of the supramastoid crest correlated with the level of the middle fossa. These surface relationships all have significance for posterolateral approaches to the cranial base. Since performing this study, these relationships have been found reliable for operative planning in our clinical cases.

Cephalometry↗

PubMed1995

Neuroanatomical details under endoscopical view--relevant for radiosurgery?

Both, neuroendoscopy and radiosurgery, are upcoming techniques in neurosurgery and become nowadays more and more important. In planning radiosurgical interventions it is very important to have both, the information about the morphology of the pathology itself, and also a clear understanding from the surrounding structures. Neuroendoscopic techniques gives the possibility to demonstrate well known structures without prior dissection. This paper focuses on these anatomical informations which might be relevant in planning further radiosurgical interventions especially in cases of the vascularization of the cranial nerves and the arachnoid membranes, these structures appears much more complex than described in "common" neuroanatomical textbooks. Endoscopic techniques also better demonstrate the real in vivo relationships and gives so a better understanding for interpreting "planning" MRI and CT scans. We therefore consider that neuroanatomical studies under a neuroendoscopical view are very important and could be very helpful in planning radiosurgical intervensitons.

Arachnoid↗

PubMed1995

Endoscopically assisted microneurosurgery.

Technological developments in neuroendoscopy are leading to an expansion of applications into the realm of microneurosurgical procedures. The new dimension that using an endoscope provides requires insight into different neuroanatomical aspects and a new kind of strategy in planning a microneurosurgical procedure. To gain some new insights into these exciting aspects of neurosurgery we have explored the sellar, parasellar, and posterior fossa regions in 50 fresh anatomical specimens and used various types of endoscopes to observe the surgically relevant neurotopographical details. We then utilized this experience in 33 clinical cases during microsurgical approaches for various lesions (posterior fossa tumors - 12 cases, sellar and parasellar tumors - 8 cases, trans-sphenoidal procedures for pituitary adenoma - 7 cases, transventricular procedures - 6 cases). In the laboratory we found that familiar neuroanatomical structures are seen in a completely different aspect from what we are accustomed. Orientation is at times difficult, which requires rehearsal and special handling of the endoscope for complex clinical procedures. We found that certain structures that are hardly noticed in routine anatomical views become very important when utilizing the endoscope (i.e., different arachnoid membranes and trabeculae). Importantly, the dimensions of a microsurgical approach can be greatly enlarged with the endoscope, making it possible to look behind structures and ''around corners''. We present our findings with respect to important anatomical details relevant to utilizing the endoscope as an adjunct to microneurosurgical procedures and our clinical data. We have concluded that the neuroendoscope can be a safe and helpful adjunct in many microneurosurgical procedures.

Endoscopy↗

PubMed1994

Endoscopic anatomy of the ventricles.

The endoscopic view offers a new anatomical dimension to the neurosurgeon. The fact makes it basically necessary to study the topographic anatomy under endoscopic conditions. In this paper attention was drawn to the ventricles because they are the most common region of clinical application. In 25 specimens neuroendoscopic explorations of the ventricles have been done. The dissections have been carried out through one- and two burr hole approaches (two working endoscopes at the same time). The instrumentation includes rigid 4 mm and 6 mm endoscopes. The procedures have been documented by continuous video recording and parallel photography.

Cerebral Ventricles↗

PubMed1993

Difficulties in examination of the origin of the vertebral artery by duplex and colour-coded Doppler sonography: anatomical considerations.

Despite progress in ultrasonographic techniques visualisation of the origin of the vertebral arteries, particularly the left, by duplex and colour Doppler imaging, still poses a problem in a significant number of patients. In anatomical and radiological studies we demonstrated an anomalous origin in 6%, the left vertebral artery originating directly from the aorta in most cases. The origin from the subclavian artery was found to be posterior in 44% and inferior in 6%. The V1 segment of the vertebral artery (from its origin to the entry into the foramen transversarium) was tortuous in 47% of cases. These anatomical variants and variations in the course of the vessel contribute to the nonvisualisation of the origin of the vertebral artery by duplex and colour Doppler imaging. With respect to tortuosities technical modifications for better visualisation are suggested and possible implications for surgery are discussed.

Aged↗

PubMed1992

The termination of the vein of "Labbé" and its microsurgical significance.

Information about the termination of the inferior anastomotic vein of Labbé is of crucial importance in the subtemporal neurosurgical approach and its modifications. An intradural course has been observed in all cases. The vein of Labbé reaches in 3/4th the anterior third of the transverse sinus, in 73% of all cases tracing a so-called tentorial sinus. By dissecting the vein of Labbé out of its dural bed and shifting its fixation point, microsurgical access is facilitated considerably.

Cerebral Veins↗

PubMed1991

Modifications of temporal approaches: anatomical aspects of a microneurosurgical approach.

All subtemporal approaches have in common the risk of temporal lobe damage. To reduce the retraction of the temporal lobe we combine two synergistic modifications of temporal approaches to reach the prepontine space. The first is the temporary resection of the zygomatic arch which allows to bring the temporalis muscle more caudally and subsequently allows an anterior subtemporal approach with only minimal temporal lobe retraction. The second modification is the resection of the apex of the petrous bone after incision of the tentorium. This provides an excellent view into the posterior fossa between the trigeminal nerve medially, the internal carotid artery caudally and the internal auditory canal laterally. The anatomical aspects of a microneurosurgical approach regarding these modifications are reported and discussed.

Brain Neoplasms↗

PubMed1991

[The intermediary nerve at its entry and exist site in the brain stem].

On 119 brain stem halves the nerve root fasciculi of the intermediary nerve were examined in respect of their position relative to the facial and vestibulocochlear nerves. The following variants were seen: 1.) the intermediary nerve lies between the facial and vestibulocochlear nerves as stated in the textbooks, in 32.9% of the cases; 2.) in 18.5% of the cases it is entirely apposited to the vestibulocochlear nerve from the beginning and branches off from that nerve only later; 3.) part of the nerve root fasciculi are apposited to the vestibulocochlear nerve and the others originate between the facial and vestibulocochlear nerves. This was seen in 49.6% of the cases.

Brain Stem↗