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O Gaber

Publications and source records attributed to O Gaber.

18 recordsLinked to original sources
PubMed2006

Computational fluid dynamics modeling of insertion and advancement of a reamer into the intramedullary canal of a long bone.

The effect of reaming velocity on the pressure distribution within the bone was investigated numerically by solving the full three-dimensional momentum equations together with the continuity equation using the finite element technique. Viscosity was also varied to obtain a pressure envelope. It was found that all the experimental data follow the same trends as the envelopes predicted by the finite element model. It was clear that an increase in either the implant insertion rate or the viscosity resulted in an increase in pressure in the intramedullary canal.

Computer Simulation↗
PubMed2003

Lateral arm flap: analysis of its anatomy and modification using a vascularized fragment of the distal humerus.

Soft tissue injuries with associated bone defects are difficult to manage and often require prolonged treatment with repeated interventions. Frequently, a free flap is applied as a first step and bone grafting is carried out in a second procedure. Ideally, these two procedures are combined in one operation, utilizing a soft tissue flap with an attached vascularized bone fragment. The lateral arm flap can provide such an osteoseptocutaneous flap and has been utilized clinically with success; however, the vascular anatomy of the flap, especially the humeral fragment, has not been described in detail previously, and there is broad disagreement concerning its innervation. In this study, the arteries and nerves of 24 fresh cadaver arms were dissected after injection of colored latex. The levels of origin of the periosteal arteries of the humerus were also documented. The lateral arm flap has a consistent arterial supply from three septocutaneous perforating branches that are arranged in a predictable pattern. The lateral supracondylar ridge of the humerus is vascularized by direct branches of the posterior branch of the radial collateral artery and by arteries that arise from muscular branches supplying adjacent muscles. The innervation of the lateral arm flap is by the inferior lateral cutaneous nerve of the arm. Knowledge of the consistent vascular anatomy of the lateral humerus and soft tissue of the donor site allows an osteoseptocutaneous flap to be raised safely with an appropriate technique. We recommend use of the lateral arm flap with a humeral fragment for the treatment of combined soft tissue and bone defects when a single step surgical solution is indicated.

Aged↗
PubMed2002

Storage phosphor radiography of wrist fractures: a subjective comparison of image quality at varying exposure levels.

Image quality of storage phosphor radiographs acquired at different exposure levels was compared to define the minimal radiation dose needed to achieve images which allow for reliable detection of wrist fractures. In a study on 33 fractured anatomical wrist specimens image quality of storage phosphor radiographs was assessed on a diagnostic PACS workstation by three observers. Images were acquired at exposure levels corresponding to a speed classes 100, 200, 400 and 800. Cortical bone surface, trabecular bone, soft tissues and fracture delineation were judged on a subjective basis. Image quality was rated according to a standard protocol and statistical evaluation was performed based on an analysis of variance (ANOVA). Images at a dose reduction of 37% were rated sufficient quality without loss in diagnostic accuracy. Sufficient trabecular and cortical bone presentation was still achieved at a dose reduction of 62%. The latter images, however, were considered unacceptable for fracture detection. To achieve high-quality storage phosphor radiographs, which allow for a reliable evaluation of wrist fractures, a minimum exposure dose equivalent to a speed class of 200 is needed. For general-purpose skeletal radiography, however, a dose reduction of up to 62% can be achieved. A choice of exposure settings according to the clinical situation (ALARA principle) is recommended to achieve possible dose reductions.

Fractures, Bone↗
PubMed2002

Direct digital radiography versus storage phosphor radiography in the detection of wrist fractures.

AIM: To define the value of digital radiography with a clinical flat panel detector system for evaluation of wrist fractures in comparison with state of the art storage phosphor radiography. MATERIAL AND METHODS: Hard copy images of 26 fractured wrist specimens were acquired with the same exposure dose on a state of the art storage phosphor radiography system and a clinical flat panel detector. Image features like cortical bone surface, trabecular bone, soft tissues and fracture delineation were independently analysed by 4 observers using a standardised protocol. Image quality ratings were evaluated with an analysis of variance (ANOVA). RESULTS: Flat panel detector radiographs were rated superior with respect to cortical and trabecular bone representation as well as fracture evaluation, while storage phosphor radiographs produced better soft tissue detail. CONCLUSION: In some of the observed image quality aspects, the performance of caesium iodide/amorphous silicon flat panel detector exceeds state of the art storage phosphor radiography. This makes it well suited for skeletal imaging particularly in trauma as seen in the detection of wrist fractures.

Analysis of Variance↗
PubMed2000

Cervical spine motion during airway management: a cinefluoroscopic study of the posteriorly destabilized third cervical vertebrae in human cadavers.

UNLABELLED: We conducted a randomized, controlled, crossover study to determine cervical spine motion for six airway management techniques in human cadavers with a posteriorly destabilized third cervical (C-3) vertebra. A destabilized C-3 segment was created in 10 cadavers (6-24 h postmortem). Cervical motion was recorded by continuous lateral fluoroscopy. The following airway management techniques were performed in random order on each cadaver with manual in-line stabilization applied: face mask ventilation (FM), laryngoscope-guided orotracheal intubation (OETT), fiberscope-guided nasal intubation (FOS-NETT), esophageal tracheal Combitube((R)) (Kendall-Sheridan, Neustadt, Germany) insertion (ETC), intubating laryngeal mask insertion with fiberscope-guided tracheal intubation (ILM-OETT), and laryngeal mask airway insertion (LMA). Afterward, maximum head-neck flexion (FLEX-MAX) and maximum head-neck extension (EXT-MAX) without manual in-line stabilization was performed to determine maximum motion. The maximum posterior displacement of C-3 and the maximum segmental sagittal motion of C2-3 were determined. There was a significant increase in posterior displacement for the FM (1.9 +/- 1.2 mm, P: < 0.01), OETT (2.6 +/- 1.6 mm, P: < 0.0001), ETC (3.2 +/- 1.6 mm, P: < 0.0001), ILM-OETT (1.7 +/- 1.3 mm, P: < 0. 01), LMA (1.7 +/- 1.3 mm, P: < 0.01), FLEX-MAX (3.7 +/- 1.9 mm, P: < 0.0001), EXT-MAX (1.8 +/- 1.7, P: < 0.01), however, not for FOS-NETT (0.1 +/- 0.7 mm). Posterior displacement was less for the ILM-OETT and LMA than for the ETC (both P: < 0.04). There were no significant increases in segmental sagittal motion with any airway manipulation other than with FLEX-MAX (-4.5 +/- 4.0 degrees, P: < 0.01). Posterior displacement was similar to FLEX-MAX for the OETT and ETC; however, it was less for the FM, FOS-NETT, ILM-OETT, and LMA (all P: < 0.01). Posterior displacement was similar to EXT-MAX for all airway manipulations other than for FOS-NETT (P: < 0.001). For cervical motion and the techniques tested, the safest method of airway management in a patient with a posteriorly destabilized C-3 segment is FOS-NETT. LMA devices may be preferable to the ETC. IMPLICATIONS: In the cadaver model of a destabilized third cervical vertebrae, significant displacement of the injured segment occurs during airway management with the face mask, laryngoscope-guided oral intubation, the esophageal tracheal Combitube (Kendall-Sheridan, Neustadt, Germany), the intubating and standard laryngeal mask airway; but not with fiberscope-guided nasal intubation. For cervical motion and the techniques tested, the safest airway technique with this injury is fiberscope-guided nasotracheal intubation. Laryngeal mask devices are preferable to the esophageal tracheal Combitube.

Aged↗
PubMed1998

Histological investigations on the Tyrolean Ice Man.

The 5,200-year-old Tyrolean Ice Man discovered in 1991 in the Otztal Alps is the world's most ancient known human glacier mummy. Histological investigation was aimed at 1) optimizing specimen preparation and 2) documenting the preservation state of (sub)cellular components. Minute pieces of frozen tissue were removed endoscopically from rib bone and cartilage, major blood vessels, oral cavity and alimentary tract, liver, spleen, diaphragm, respiratory system, femoral muscle and nerve, sympathetic trunk, brain, and skin. Double fixation with glutaraldehyde followed by osmium tetroxide and embedding in Epon/Araldite epoxy resins proved to be the method of choice for both light and transmission electron microscopy combined with classical histochemistry. In particular, mild evacuation of the desiccated tissue was determined to be essential to ensure homogeneous infiltration with fixatives and resins; as a result, sections of excellent quality could be obtained with any kind of sample. With regard to the preservation degree of (sub)cellular components, distinct tissue-specific patterns were observed. There were highly intact skeletal and connective tissues proper, however, most interestingly, there were remarkably intact nervous tissue components as well. By contrast, epithelial, muscle, and reticular connective tissues as well as blood had generally disintegrated due to autolysis, freeze/thaw damage, and adipocere formation. For a tentative interpretation of these patterns, we considered general aspects of cryopreservation, such as physicochemical properties of subcellular constituents and tissue physiology.

Adult↗
PubMed1998

[3D navigation for interstitial stereotaxic brachytherapy].

AIM: The aim of this paper is to describe the adaption of 3D-navigation for interstitial brachytherapy. The new method leads to prospective and therefore improved planning of the therapy (position of the needle and dose distribution) and to the possibility of a virtual simulation (control if vessels or nerves are on the pathway of the needle). MATERIAL AND METHODS: The EasyGuide Neuro navigation system (Philips) was adapted in the way, that needles for interstitial brachytherapy were made connectable to the pointer and correctly displayed on the screen. To determine the positioning accuracy, several attempts were performed to hit defined targets on phantoms. Two methods were used: "free navigation", where the needle was under control of the navigation system, and the "guided navigation" where an aligned template was used additionally to lead the needle to the target. In addition a mask system was tested, whether it met the requirements of stable and reproducible positioning. The potential of applying this method in clinical practice was tested with an anatomical specimen. RESULTS: About 91% of all attempts lied within 5 mm. There were even better results on the more rigid table (94% < 4 mm). No difference could be seen between both application methods ("free navigation" and "navigation with template"), they showed the same accuracy. CONCLUSIONS: The accuracy of the phantom experiments and the confirmation by the experiment with the anatomical specimen showed that excellent results can be expected in clinical practice using rigid tables and patient supporting systems.

Brachytherapy↗
PubMed1998

Importance of arterial blood supply to the femur and tibia for transplantation of vascularized femoral diaphyses and knee joints.

The role of the periosteal and intraosseous blood supply to the femur and the proximal tibia was investigated to improve the operating technique for transplantation of allogenic vascularized femoral diaphyses and knee joints in humans. Altogether 48 limbs were injected with gelatin, red latex milk, or Revertex and macroscopically prepared; 41 limbs were studied for the variation and division of the truncus profundo-circumflexus. In 200 femurs and 200 tibias the location of the nutrient foramen was determined. The arteries supplying the periosteum of the distal femur and the proximal tibia have defined nutritive areas. The following technique should be followed: If the femoral artery alone is prepared as the vascular pedicle, the optimal section for resection of the femur in knee joint transplantations is 6 to 12 cm above the level of the femur condyles and 5 to 7 cm below the tibial plateau. For the transplantation of femoral diaphyses, the deep femoral artery can be used if the lateral femoral circumflex artery is protected. The Proximal line of resection is defined between the greater and lesser trochanter. For shorter grafts one must consider the number and location of nutrient foramens. For longer grafts the distal branches of the femoral artery must be respected as the intraosseous blood supply reaches distally down to the level of about 8 cm above the femoral condyles. In all these operations of the variation of the truncus profundo-circumflexus and the trifurcation of the popliteal artery must be considered.

Aged↗
PubMed1997

Otorhinolaryngologic computer-assisted biopsies of the Iceman.

BACKGROUND: The Iceman is a prehistoric, completely preserved, 5300-year-old male human mummy. OBJECTIVE: To obtain the first biopsy specimens from inside the Iceman while meeting an extended standard of hygiene and following precise intraoperative guidance to the site of biopsy and keeping tissue damage to a minimum. DESIGN: Biopsy specimens from the nose, the maxillary sinus, and the larynx of the Iceman were obtained. Special caution had to be taken while performing the biopsies to not contaminate the Iceman with heavy metals or remnants of microorganisms. SUBJECT: The Iceman, a cadaver kept frozen in a glacier for 5300 years. The Iceman is in an excellent state of preservation and will allow fundamental histological, morphological, and molecular genetic insights into early man. INTERVENTION: The biopsies were planned and executed with the aid of Interventional Video Tomography, a system that guides the surgeon to the target area by combining live video with existing imaging modalities. The system does not need mechanical fixation of the subject (the Iceman) and is barely in physical contact with the subject; thus, it was the ideal tool for guiding the surgeon to the site of the biopsy samplings through a tiny canal into the nose, the maxillary sinus, and the larynx of the Iceman. RESULTS: We have obtained a number of tissue samples by precisely guided 3-dimensional navigation. Unnecessary tissue damage was avoided. CONCLUSIONS: Visual inspection of the extracted mucosa showed typical human cadaver tissue, despite its age, without clinical abnormalities. Currently, the samples are being investigated by various international scientific groups.

Animals↗
PubMed1995

Soluble HLA antigens and ELISA--a new technology for crossmatch testing.

A soluble HLA ELISA for the detection of donor specific anti-HLA class I IgG antibodies was developed and compared with microlymphocytotoxicity. Donor sHLA was prepared from donor blood or purified blood lymphocytes and captured onto monoclonal antibody coated ELISA plates. After incubation of captured HLA with test serum, bound IgG antibodies were detected using a peroxidase-conjugated anti-human IgG antibody. Serum samples from patients on waiting lists to receive kidney transplants were tested by lymphocytotoxicity (AHG protocol) and/or sHLA ELISA in four different laboratories using HLA preparations from eight organ donors. Concordant crossmatch results were obtained for 854 (99%) of 864 ELISA crossmatches. In contrast, concordant results were obtained for 234 (91%) of 256 lymphocytotoxicity crossmatches. Interlaboratory reproducibility of ELISA results was 99%. In contrast, interlaboratory reproducibility of lymphocytotoxicity assay results was 78%. Endpoint titrations of serum specimens containing anti-HLA antibodies demonstrated equivalent sensitivity of ELISA and AHG lymphocytotoxicity crossmatch and similar sensitivity of ELISA and flow cytometry crossmatch. Specimens tested positive by lymphocytotoxicity without DTT treatment but negative with DTT treatment were tested negative by ELISA. Comparison of lymphocytotoxicity and ELISA crossmatch results showed an agreement of 94%. This demonstrates that detection of anti-donor HLA class I antibodies by ELISA is a reliable alternative to microlymphocytotoxicity testing.

Enzyme-Linked Immunosorbent Assay↗
PubMed1995

Fiber orientation of posterior cruciate ligament: an experimental morphological and functional study, Part 2.

The posterior cruciate ligament (PCL) can be anatomically divided into three bundles: anterolateral, posteromedial, and posterior oblique. The changes in distance between the femoral and tibial attachment sites of these three bundles were measured in 10 human knee specimens with intact ligamental structures. The femoral to tibial distance (and thus the length) of the posterior oblique bundle remained nearly the same throughout flexion between 0 degrees and 90 degrees. The femoral to tibial distance of the anterolateral and the posteromedial bundles distinctly changed throughout the same range of motion. For a truly functional replacement of the PCL, correct isometric placement of the transplant is especially important. Based on the results of the present study, an isometric reconstruction of the PCL is achieved by positioning the graft within the original attachment site of the posterior oblique bundle.

Humans↗
PubMed1994

Radioisotopic evaluation of renal function in cyclosporine-treated pediatric and adult renal transplant recipients and their living donors. A study of 152 donor-recipient pairs.

Renal function was studied in 2 groups of renal transplant recipients and their donors by technetium-99m diethylenetriamine pentaacetic acid and a gamma camera. The pediatric group (group A) comprised 40 children and their adult kidney donors. The adult group (group B) consisted of 112 consecutive adult renal transplant recipients and their adult donors. All patients received kidneys from living donors and were given the same immunosuppression protocol (PRED plus CSA). Donor glomerular filtration rate (GFR) was determined before nephrectomy and at a mean period of 30 (range 10-50) months after nephrectomy. The graft GFR was measured at 1, 3, 6, and 12 months and at the most recent follow-up visit. Moreover, the functional reserve of the graft was assessed by infusion of dopamine and an amino acid. The postnephrectomy GFR of donors in groups A and B were 74 +/- 18 and 72 +/- 20 ml/min/1.73 m2, respectively. The GFR of pediatric recipients was significantly lower than that of adult recipients at corresponding time points along the course of follow-up. The mean values of graft GFR were 47.6 +/- 20 and 63.8 +/- 29.6 ml/min/1.73 m2 for pediatric and adult recipients, respectively (P < 0.001). Moreover, the graft functional reserve was significantly lower in pediatric recipients. These data demonstrate that adult kidneys transplanted into pediatric recipients have lower GFR than those transplanted into adults, despite corrections for body surface area. Although the reason for this phenomenon is unknown, the observation may have important implications for management of pediatric recipients.

Adolescent↗
PubMed1989

[Anatomy of the cruciate ligaments in CT].

The morphological foundations of CT-imaging of the cruciate ligaments in 4 different positions of examination are presented comparing roughly identical anatomical sections with CT-scans. Several parts of the cruciate ligaments, such as origin, course and insertion can be viewed in different CT-planes.

Adult↗
PubMed1985

[The vascularization of the menisci. Morphological basis for the repair].

Degeneration of the knee joint and increase of anterior-posterior tibial displacement are resulting from total meniscectomy, especially in knees with anterior cruciate deficiency. Vascularisation of the meniscus was studied in 12 cadaver knees after latex injection of vessels. Vascularisation of the anterior and posterior horns was found to be much better than that of the body of meniscus. All vessels originated from the popliteal artery, but variably in importance, and formed the perimeniscal and subsynovial network. 11 peripheral meniscus tears (8 freshly injured, 3 ruptures older than 2 months) were repaired by refixation, followed by immobilisation for 6 weeks. Arthroscopy 3 months postoperatively showed complete healing of all tears. Clinical examinations--follow-up for 14 months--showed no signs of rerupture in any of the patients.

Cartilage, Articular↗
PubMed1985

[Macroscopic blood supply of the tendons of the superficial and deep flexor muscles of the fingers in the palm].

The flexor tendons in the region of the palm obtain their blood supply from an arterial network in the peritenon, which is fed by the superficial palmar arch and its branches. Rarely this network is supplied by the deep palmar arch. The origin, course and number of the arterial branches supplying the flexor tendons are described in detail. At least one of these nutrient arteries must be preserved in flexor tendon surgery. An adequate arterial supply of the tendons in the digital sheath can only be ensured by preserving all vincula tendinum.

Arteries↗
PubMedDate not supplied

Man from the Hauslabjoch.

On September 19, 1991, at an altitude of 3,200 m (10,498 feet), the remains of a well-preserved, freeze-dried mummified body of a 3,000 BC, Late Stone Age man, was found on the Austrian-Italian border. Studies conducted at the University of Innsbruck have revealed that these are the remains of a 45-46-year-old male, 45 kg (99 lbs) (living weight) and 160 cm (5 feet, 2 inches) tall. Morphometric, pathophysiologic, paleobotanical, photogrammetric, anthropological, computer tomographic, and other studies have been conducted to determine the living conditions and possible causes of death of this Late Stone Age man.

Animals↗