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Biomedical subjects

W J Spitzer

Publications and source records attributed to W J Spitzer.

At least 19 recordsLinked to original sources
PubMed2006

Dentofacial rehabilitation by osteodistraction, augmentation and implantation despite osteogenesis imperfecta.

Osteogenesis imperfecta-- a heritable systemic disorder characterized by enhanced bone fragility-- is frequently associated with a Class III malocclusion and distinct dental disorders. This patient, suffering from a late form of osteogenesis imperfecta, displayed early loss of teeth and severe maxillary hypoplasia. Bone grafting of the alveolar ridge was assumed not to guarantee a neutral basal relation before dental implantation. Due to the risk of atypical fractures conventional orthognathic surgery was excluded in the atrophic maxilla. In contrast to a conventional Le Fort I osteotomy, osteodistraction of the maxilla can be performed omitting the precarious down-fracture procedure. Despite a lack of reports on this technique in patients with osteogenesis imperfecta, dysgnathia was corrected by osteodistraction of the upper jaw. The loss of teeth was treated by augmentation of the alveolar crest using autogenous bone from the iliac crest followed by placement of dental implants. Stable normocclusion of the implant-supported overdentures was achieved without any detectable relapse over 4 years. For the first time it has been demonstrated that advanced surgical techniques like osteodistraction, alveolar crest augmentation and dental implantation can successfully be combined for dentofacial rehabilitation even in patients suffering from osteogenesis imperfecta.

Adult↗
PubMed2004

[Phylogenetic aspects of lip function].

Lips can be considered a phylogenic summary of nasolabial and facial muscle evolution. They represent the central point of facial morphogenesis. The progressive development of oral and facial functions is an elementary human necessity for feeding, suction, oral competence, swallowing, language, and mimics. Each discontinuity causes functional and anatomic disorders. Any damage to the lips creates facial unbalance. Precise knowledge of lip function is indispensable for optimal reconstruction.

Adolescent↗
PubMed2002

New model for in vivo quantification of microvascular embolization, thrombus formation, and recanalization in composite flaps.

BACKGROUND: Microthrombi are suggested to be involved in the pathogenesis of composite flap failure. Due to the lack of appropriate experimental models, however, the significance of microvascular thrombus formation and microthromboembolization in free flap failure remains poorly understood. The purpose of this study was therefore to develop a rat hindlimb model that allows tissue-confined in vivo analysis of thrombus formation, thromboembolization, and recanalization within the microcirculation of osteomyocutaneous flaps using intravital fluorescence microscopy. MATERIALS AND METHODS: Thrombus formation was induced photochemically in individual arterioles and venules of muscle, subcutis, and periosteum. To study thromboembolization, autologous arterial thrombi (40 microm) were preformed in vitro and were injected into the femoral artery supplying the osteomyocutaneous flap. RESULTS: First platelet deposition was found independent from microvascular red blood cell velocity, while the subsequent growth of thrombus correlated inversely with red blood cell flow measured in the respective microvessel. Time required for complete thrombotic arteriolar occlusion exceeded 700 s, whereas thrombus growth in venules was found to be significantly accelerated ( approximately 300 s) without differences between the individual tissues analyzed. The embolization resulted in a complete shutdown of capillary perfusion in muscle, subcutis, skin, and periosteum. During subsequent spontaneous recanalization, capillary perfusion increased in all tissues to approximately half of baseline, however, without further recovery during the 4-h postembolization period. CONCLUSIONS: The model presented is suitable to quantitatively study the pathophysiology of microvascular thrombus formation, thromboembolization, and recanalization in composite flaps, and may thus be used to evaluate the effectiveness of novel therapeutic strategies to prevent flap failure.

Animals↗
PubMed2002

Microvascular transfer-related abrogation of capillary flow motion in critically reperfused composite flaps.

Capillary flow motion is defined as rhythmic fluctuations of blood flow in the capillaries. Although critical perfusion has been demonstrated to induce capillary flow motion, little is known about the role of capillary flow motion in microvascular free flaps. The aim of this study was to elucidate the tissue-confined incidence and consequence of capillary flow motion in microvascularly transferred composite flaps, using intravital fluorescence microscopy. In Wistar rats, transferred osteomyocutaneous flaps (n = 7), which were exposed to 1 h of ischaemia during the anastomotic procedure followed by 1 h of reperfusion, were subjected to critical perfusion by stepwise reduction of the femoral-artery blood flow to 0.15 ml min(-1), 0.10 ml min(-1) and 0.05 ml min(-1). Pedicled osteomyocutaneous flaps that were not subjected to ischaemia (n=8) served as controls. In pedicled flaps critical perfusion induced capillary flow motion in the muscle, but not in the skin, subcutis and periosteum. In these flaps, the functional capillary density was preserved in all tissues analysed, including the skeletal muscle. Additional sympathetic denervation of the pedicled flaps did not change the incidence or pattern of capillary flow motion. In contrast, after flap transfer capillary flow motion in muscle tissue did not occur during critical perfusion. As a consequence, a shutdown of perfusion of individual capillaries was observed, resulting in a significant reduction (P<0.05) in functional capillary density, not only in the subcutis, skin and periosteum but also in the muscle itself. Thus, our data suggest that the microcirculatory control of pedicled osteomyocutaneous flaps is preserved during critical perfusion by skeletal-muscle capillary flow motion, whereas this protective regulatory mechanism is lost during the initial reperfusion period after flap transfer, probably not because of denervation but because of surgery- and/or ischaemia-reperfusion-associated injury.

Animals↗
PubMed2001

Local heat-shock priming-induced improvement in microvascular perfusion in osteomyocutaneous flaps is mediated by heat-shock protein 32.

BACKGROUND: Stress conditioning is thought to improve microvascular free flap survival but the mechanisms of protection are not clear. The aim of this study was to determine whether local induction of heat-shock protein (HSP) 32 improves microvascular perfusion in transferred osteomyocutaneous flaps. METHODS: The hindlimb harvest region of osteomyocutaneous flaps in Wistar rats was subjected to stress conditioning by local heating (30 min, 42.5 degrees C) 24 h before microvascular flap transfer. In a second group of animals, after heat-shock priming, the action of HSP-32 was inhibited by tin protoporphyrin IX. Animals with unconditioned flaps served as controls. After transfer, the microcirculation of the muscle, cutaneous, subcutaneous and periosteal tissue of the flap was analysed quantitatively for 6 h using intravital fluorescence microscopy. RESULTS: Immunohistochemistry revealed that HSP-32 was detectable only after priming and not in unconditioned flaps. Priming did not alter functional capillary density or capillary red blood cell velocity compared with that in unconditioned flaps. However, heat-shock priming induced significant capillary dilatation (P < 0.05) and thus a substantial increase in capillary blood flow volume (P < 0.05) in all tissues of the transferred flaps. Inhibition of HSP-32 by tin protoporphyrin IX completely abolished the priming-induced improvement in capillary perfusion, as indicated by the lack of increased capillary diameters and volumetric blood flow. CONCLUSION: The present study demonstrated that stress conditioning by local heat-shock priming improves nutritive perfusion in osteomyocutaneous flaps by capillary dilatation, probably mediated through the vasoactive action of HSP-32.

Animals↗
PubMed2001

Reduction of inflammatory response in composite flap transfer by local stress conditioning-induced heat-shock protein 32.

BACKGROUND: The failure of composite flaps despite anastomotic patency is thought to be mediated by the inflammatory response within the microvasculature, which results from unavoidable surgical trauma and transfer-related ischemia-reperfusion. Evidence suggests that stress conditioning may improve flap survival; however, the molecular mechanisms of protection are far from being clear. Therefore, we analyzed whether stress conditioning-induced heat-shock protein 32 is effective to prevent the inflammatory response in transferred osteomyocutaneous flaps. METHODS: In a rat model, leukocyte-endothelial cell interaction and endothelial integrity disruption as early indicators of the inflammatory response were quantitatively analyzed in muscle, subcuticular tissue, and periosteum of microvascularly transferred osteomyocutaneous flaps by using intravital fluorescence microscopy. Twenty-four hours before flap transfer, stress conditioning was induced by local heating of the left hindlimb up to 42.5 degrees C for 30 minutes. In additional animals, stress conditioning-induced activity of heat-shock protein 32 was inhibited by tin protoporphyrin-IX. Unconditioned flaps served as controls. RESULTS: In all tissues analyzed, control flaps showed significant leukocyte adherence in postcapillary venules, increased intercellular adhesion molecule-1 (ICAM-1) expression, and endothelial integrity disruption, but a lack of heat-shock protein 32. In contrast, stress conditioning induced marked heat-shock protein 32 expression, which was associated with a significant reduction (P <.05) of leukocyte adherence, ICAM-1 expression, and endothelial hyperpermeability. The inhibition of heat-shock protein 32 by tin protoporphyrin-IX completely abolished the stress conditioning-induced amelioration of the inflammatory response in all tissues analyzed. CONCLUSIONS: Stress conditioning by local heat-shock priming reduces the inflammatory response in osteomyocutaneous flaps. The protective effect is predominantly mediated by the induction of heat-shock protein 32.

Animals↗
PubMed2000

[Roentgen diagnosis in oromaxillofacial surgery].

A vital X-ray imaging technique in oral and craniomaxillofacial surgery is the panoramic X-ray. Due to its variety of special projections, including imaging of the transversal level and low exposure to radiation, it is suitable for answering many clinical questions and for diagnostics of various findings. It has become possible to minimize the necessary doses by further development of technology and devices, as well as of X-ray films and by new detection systems, such as sensors or screens. In some clinical cases, the diagnostic deficiencies of conventional imaging techniques make computed tomography (CT) and magnetic resonance (MR) imaging indispensable. Although MR is particularly suitable for soft tissue imaging, it has also become helpful in finding cortical changes by shorter measuring times. In certain cases, e.g., changes to bone metabolism, differentiated methods of nuclear medicine make image-aided analysis of function possible.

Diagnostic Imaging↗
PubMed1999

In vivo analysis of the microcirculation of osteomyocutaneous flaps using fluorescence microscopy.

Previous studies have indicated that freely transferred osteomyocutaneous flaps may fail despite anastomotic patency. While microvascular dysfunction is thought to be one of the major causes for this type of flap failure, little is known of its underlying mechanisms, probably due to the lack of adequate experimental models allowing detailed intravital microcirculatory analysis. Herein we report quantitative analysis of the microcirculation of periosteum, muscle, subcutis and skin by intravital fluorescence microscopy using an osteomyocutaneous free flap model in the hindlimb of rats. The microcirculation of the different tissues was studied after microanastomotic transfer (free flap), and was compared to that after solely elevating the tissue, mimicking a pedicled osteomyocutaneous flap. Transferred flaps, which were exposed to 1 h of ischaemia during the anastomotic procedure, showed a slight but significant decrease (P< 0.05) of functional capillary density in muscle, subcutis and skin when compared with the microcirculation of pedicled flaps, while capillary diameters, red blood cell velocity and blood flow of perfused capillaries remained almost unaffected. The decrease of functional capillary density was associated by a significant (P< 0.05) inflammatory response, as indicated by the increased number of leukocytes adherent to the endothelial lining of postcapillary venules. While the functional capillary density of periosteum was not affected by the free transfer procedure, the inflammatory response was found similar when compared with that observed in muscle and subcutis. Thus, our study indicates that even after a short 1-h ischaemic time period, capillary perfusion failure and leukocyte-endothelial cell interaction are the main events, characterising microvascular dysfunction after free transfer of osteomyocutaneous flaps. Using the model described herein, intravital microscopic analysis of the microcirculation proved an appropriate tool to study the individual microvascular response after free tissue transfer, and may thus be used to evaluate the effectiveness of novel therapeutic regimens which aim at counteracting microcirculatory dysfunction in free osteomyocutaneous flaps.

Animals↗
PubMed1997

Surgical management of mandibular malposition after malunited condylar fractures in adults.

Fourteen patients who had occlusal disturbance and mandibular malposition following malunited condylar fractures are presented, to demonstrate the variety of surgical corrective procedures used. In order to achieve an anatomically correct mandibular position, a subcondylar osteotomy was performed in 2 patients, and in 11 patients a uni- or bilateral sagittal split osteotomy was carried out. In 1 patient, a Le Fort I osteotomy was the method of choice. In all patients, it was possible to correct the occlusal and mandibular imbalance, as well as to facilitate normal mandibular movement.

Adult↗
PubMed1996

[Diagnostic imaging for therapy planning of orofacial malformations].

Two-dimensional conventional X-rays and computer tomographic imaging systems contribute to the diagnosis and surgical planning of patients with orofacial malformations. The ability to reformat CT scans into three-dimensional osseous and soft tissue surface images has a significant impact on the diagnosis and management of orofacial malformations. Cephalometric evaluation with teleradiography provides precise insight into both the skeletal structures and the soft parts, enabling the radiologist to assess the relationship among the different parts in a given subject, at any given time and in relation to the normal.

Adult↗
PubMed1996

Educational preparation for contemporary health care social work practice.

Health and health care delivery continue as dominant domestic issues in the United States. Health also represents a highly sophisticated social work practice area, requiring specific expertise for intervention with complex biopsychosocial patient care issues. Current social work curriculum content must reflect contemporary practice issues and educational resources must be improved to meet the documented need for adequately prepared health care professionals. This paper proposes a curriculum template for practice education and offers additional recommendations to enhance the educational process through increased field and academic collaboration.

Cost Control↗
PubMed1994

Mandibular reconstruction with cancellous bone, hydroxylapatite and titanium mesh.

Over the past 20 years, titanium mesh combined with autologous iliac crest spongiosa and hydroxylapatite has performed well in the restoration of mandibular discontinuity defects in 79 patients. In 14 irradiated patients with a transplant bed of inferior quality, however, complications and failures occurred more often than in the 65 non irradiated patients. The results of our investigation clearly show that the success of mandibular reconstruction mainly depends on a well vascularized transplant bed.

Adult↗
PubMed1994

[Xenogenic cartilage as a transplant for reconstruction of the facial skull].

90 patients were followed-up, in whom 110 cartilage grafts of bovine origin (Chondroplast) had been inserted. Nose and orbit (46 and/or 32 cartilage grafts) were the most frequent implantation sites. In three out of those 90 patients incorporation of the grafts was eventful. In two out of those three complication finally resulted in a loss of the graft. When following-up in 57 patients whether the grafts had kept their shape we found out that the cartilage grafts had still kept their shape quite well after three and a half years in 50 patients.

Animals↗
PubMed1994

[Reconstruction of the orbital walls by autologous calvarial transplants].

This article reports on the experience gained with outer table calvarial bone grafts used for the reconstruction of the bony orbital walls in 43 patients. The transplants were harvested in the parietal area above the non-dominant hemisphere. Morbidity and complication rate at the harvest site were extremely low. In all patients the grafts became uneventfully incorporated.

Bone Transplantation↗
PubMed1994

[Limits of osseous reconstruction of the mandible with autologous spongiosa, hydroxyapatite granules and titanium mesh, especially after radiotherapy].

Over the past twenty years the titanium mesh combined with autologous iliac crest spongiosa and hydroxylapatite has performed well in the restoration of mandibular discontinuity defects in 79 patients. In 14 irradiated patients with a transplant bed of inferior quality, however, complications and failures occurred more often than in the 65 not irradiated patients. The results of our investigation clearly show, that the success of mandibular reconstruction mainly depends on a well vascularized transplant bed.

Adult↗