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Biomedical subjects

V Bühren

Publications and source records attributed to V Bühren.

At least 55 records · Page 3Linked to original sources
PubMed1998

Allogeneic vascularized grafting of human knee joints under postoperative immunosuppression of the recipient.

Vascularized knee joint transplantations have been performed in various animal systems. Up to now no allogeneic vascularized transplantation of a fresh and perfused human knee joint has been realized. This paper reports on the first four grafted human knee joints, performed between April 1996 and July 1997 at the Trauma Center Murnau. The indication for transplantation of a human knee joint is total loss of the joint, including the extensor apparatus, following severe trauma. Management of this defect is first to effect closure of the soft tissue defect combined with external transfixation and bone cement spacers. For the second phase the external stabilization is switched to internal stabilization using femoral tibial nails and a temporary knee joint prosthesis manufactured of polyethylene. The transplantations are performed with respect to ABO compatibility, ignoring the HLA system after a negative crossmatch. Osteosyntheses are employed by femoral and tibial nails. The vascular anastomoses are established in an end-to-side technique between the recipient's superficial femoral vessels and the graft vascular pedicles. Immunosuppression starts as quadruple induction therapy for 3 days. Subsequently it is reduced to a two-drug maintenance protocol with cyclosporin A and azathioprine. We utilize radiography, digital subtraction angiography, duplex sonography, scintigraphy, and arthroscopy for graft monitoring. Six months after transplantation the osteotomies were bridged with callus, and the patients were completely mobilized. The motion in the transplanted knee joint ranges from complete extension to 110 degree flexion.

Adolescent↗
PubMed1998

Interlocking compression nailing: a report on 402 applications.

Nailing techniques have changed tremendously in recent years. One significant development has been the interlocking compression nail (ICN) which provides active interfragmentary compression. Apart from its beneficial effect in the treatment of acute fractures, allowing early weight-bearing and mobilization of the patient the ICN is useful in many types of revision operations: resection and stabilization of pseudarthroses without cancellous bone grafts, corrective operations of malalignments through a minimally invasive technique, as well as the readaptation of the resection sites in arthrodeses. Between April 1993 and September 1996, 402 consecutive applications of an ICN were followed prospectively to evaluate the practibility and reliability of the system. A special focus was placed on the active compression device. Along with 153 acute fractures, 112 non-unions and 41 cases of malalignment were treated; 96 arthrodeses were performed. Even for difficult courses of healing only a low complication rate was observed, and a remarkably high percentage was managed successfully.

Adult↗
PubMed1998

Allogeneic vascularized transplantation of human femoral diaphyses and total knee joints--first clinical experiences.

This article has presented the preliminary results of three patients who received vascularized allogeneic femoral diaphyses and three patients having undergone vascularized transplantation of fresh and perfused total human knee joints. The large osseous defects in the femora followed osteomyelitis and chondrosarcoma. The three knee joints were lost due to various trauma mechanisms. All grafts were harvested within 25 hours from multiorgan donors perfused with 4 L of UW solution. All osteosyntheses were performed employing intramedullary nails. Vascular pedicles of the grafts were anastomosed end-to-side to the superficial femoral artery and vein in the adductorial canal of the recipient thigh. Immunosuppression was based mainly on two drugs: CyA and AZA. Perfusion of the grafts was demonstrated by DSA, and bone metabolism in the graft by SPECT scintigraphy. Six months after the operation all osteotomies demonstrated callus formation and osseous consolidation in conventional radiographs. Biopsies of the grafted bone revealed intact osteocytes, and arthroscopy of the transplanted knee joints demonstrated intact synovial, chondral, and ligamentous structures. From the surgical aspect, the vascularized transplantation of the femoral diaphyses and total knee joints is technically feasible. The main problems are immunologic. All transplantations were performed with respect to ABO compatibility, but with a large HLA mismatch. Therefore, acute and chronic rejection crises were observed. In total synovial joints, lifelong immunosuppression of graft recipients seems to be currently unavoidable.

Adult↗
PubMed1998

Neutrophil activation after skeletal muscle ischemia in humans.

The aim of the study was to investigate the time course of neutrophil activation after skeletal muscle ischemia in humans and to assess the effect of xanthine oxidase inhibitor allopurinol or cyclooxygenase inhibitor indomethacin. In patients undergoing tourniquet ischemia of the upper limb, polymorphonuclear neutrophils (PMN) were simultaneously isolated from antecubital vein blood of both the contralateral control arm and the tourniquet arm. PMN-superoxide production (PMN-SOP) was determined by a cytochrome C reduction assay, PMN-myeloperoxidase activity (PMN-MPO) by guaiacol oxidation and serum PMN-elastase concentration by an enzyme immunoassay. At 60 min after release of the tourniquet, significant increases of PMN-SOP, PMN-MPO, and serum elastase concentrations were observed in tourniquet arms as compared with control arms (p < .05). Allopurinol (300 mg orally, 12 and 2 h before ischemia) significantly inhibited the increase of PMN-SOP, PMN-MPO, and serum elastase (p < .05). Indomethacin (50 mg orally, 2 h before ischemia) prevented increased PMN-MPO and serum elastase, but prevented increased PMN-SOP only when neutrophils were incubated in the presence of their autologous plasma. These findings suggest that ischemia/reperfusion of human skeletal muscle involves both xanthine oxidase-dependent oxygen free radicals and cyclooxygenase metabolites. These pathways could activate circulating neutrophils which potentially inflict local and remote endothelial injury.

Adolescent↗
PubMed1998

[As lumbago treated, delayed diagnosis of large intestine perforation with extremely severe peritonitis--case report with focus on the value of diagnostic laparoscopy].

We report on a colon perforation with peritonitis which remained clinically undetected until the 4th day post trauma although the patient suffered from lumbalgia-like symptoms. He then developed an acute abdomen with sudden onset, being caused by a sigmoidal rupture and a consecutive diffuse peritonitis. A colon resection was performed according to the Hartmann procedure. Almost 36 revisions were necessary due to necrosis and perforation. Having treated the peritonitis successfully it was possible to close the abdomen and to remove the stomata. The case is discussed in relation to standard diagnostic procedures while a special interest is focused on the usage of sonography, explorative laparoscopy and laparotomy. We finally introduce the algorithm being applied to similar cases at our trauma center.

Abdomen, Acute↗
PubMed1998

[Indications for surgical management of injuries of the cervical spine].

The indication for operative treatment of serious injuries to the cervical spine is basically determinated by instability and dislocation. Timing of the operation is based on the neurological deficit. If there is a chance for recovery operative treatment is urgent. For the upper cervical spine defined indications are existing for type-2-fractures of the dens and C 2/C 3-instabilities of the hangman-type with major dislocation. Fractures of C 0 and C 1 are preferably treated by conservative methods. Only cases with compound injury patterns with a high degree of ligamentous instability may require dorsal fusion. For serious injuries of the lower cervical spine operative treatment is needed in most instances. Conservative treatment is only indicated if functional stability can be proofed and injuries to the discs and compression to the myelon are ruled out.

Cervical Vertebrae↗
PubMed1998

[Thoracoscopic management of fractures of the thoracic and lumbar spine].

In 90 patients, stabilization of injuries of the thoracic spine and the thoracolumbar junction was performed using minimally invasive thoracoscopy. The method includes partial corporectomy with spinal decompression, interposition of a tricortical bone graft, and anterior spondylodesis by planting. Complications were rare and not severe, with only two conversions to open technique. Compared to the open, standard method benefits included reduced postoperative pain, shorter hospital stay and reduced morbidity.

Adult↗
PubMed1998

[Bridging long bone and joint defects with allogeneic vascularized transplants].

Three patients with large osseous defects following trauma and infection received vascularized allogeneic femoral diaphyses and five patients vascularized allogeneic total knee joints. From the surgical aspect these transplantations are technically feasible. The remaining problems are of immunological nature; at least in patients with allogeneic synovial joints, lifelong immunosuppression seems to be currently unavoidable.

Bone Transplantation↗
PubMed1997

Allogeneic vascularized grafting of a human knee joint with postoperative immunosuppression.

In this paper we report the first successful allogeneic vascularized transplantation of a fresh and perfused human knee joint. A 17-year-old male had lost his knee in a motorvehicle accident. The graft was harvested from a multiorgan donor, perfused with 41 UW solution and transplanted within 21 h. Osteosyntheses were performed employing intramedullary nails. Immunosuppression was based mainly on two drugs: cyclosporin A and azathioprine. Five months after the operation the patient is fully mobilized, and the graft perfusion still intact. Osteotomies of the femur and tibia demonstrate callus formation and osseous consolidation.

Accidents, Traffic↗
PubMed1997

The arterial blood supply of the human patella. Its clinical importance for the operating technique in vascularized knee joint transplantations.

The architecture of the arteries supplying the patellar rete was examined in 14 anatomic specimens in order to develop an optimized operating technique for knee joint transplantation. The specimens were fixed in Jores Solution and exarticulated from the hip joint. The lower limbs were injected with Berliner-Blau-Gelatin, and the arteries were dissected macroscopically. Five to six main arteries entered the patellar rete at 1, 3, 5, 7 and 11 o'clock forming an arterial circle. These arteries were the same main arteries which supply the distal end of the femur and the proximal part of the tibia. From an anatomic perspective, they provide the complete arterial blood supply to a whole knee joint being transplanted including the patella. Based on these anatomic results, we transplanted two allogenic vascularized human knee joints preserving the patella, the capsule, and the patellar ligament. Up to six months after surgery we demonstrated the perfusion and viability of all three transplanted bones, particularly the patella, by 99mTc DPD scintigraphy. We compared these findings with knee joint arthroscopy and with histologic results from biopsies taken from the patella. The postoperative examinations clearly indicated the viability of the transplanted patella employing this new operating technique. The results of the entire study demonstrate that it is technically feasible to transplant a whole knee joint which remains clinically viable.

Adult↗
PubMed1997

[Minimally invasive ventral spondylodesis in injuries to the thoracic and lumbar spine].

Thirty-eight patients with 40 fractures of the thoracic spine and the thoracolumbar junction were treated by a minimally invasive procedure, which includes partial corporectomy, the interposition of a tricortical bone graft and anterior stabilization by plate spondylodesis under thoracoscopic control. For 36 patients the operation was successfully performed in a complete thoracoscopic way; in 2 patients conversion to an open technique was necessary. Two postoperative complications such as a reversible lesion of the thoracodorsalis nerve and a transient irritation of nerve root L1 on the approach side were encountered. Postoperative control by X-ray and CT scan showed correct positioning of the bone graft, as well as the fixation device in all patients. Our experience with this minimally invasive stabilizing procedure for injuries of the thoracic spine and the thoracolumbar junction demonstrated the feasibility of the method. Compared to the open method the benefit of minimally invasive surgery included postoperative pain reduction, shorter hospitalization, early recovery of function and reduced morbidity of the operative approach.

Adult↗
PubMed1997

[The osteosynthesis implant and early postoperative infection: healing with or without removal of the material?].

This prospective study served as a quality control of a revision concept for case of post-traumatic infection following open reduction and internal fixation in fracture treatment. It is based on clinical and microbiological criteria and has two aims: (1) eradication of the infection and avoidance of development of chronic osteitis; (2) maintenance of internal fixation, if possible. Thirty-four patients were recruited in this study. Surgical revisions were performed according to a consistent concept (debridement, irrigation, local chemotherapy, drainage) in defined time intervals (2 days). The operation site had to be bacteriologically clean after four revisions. Otherwise, the implant had to be removed. Both aims were reached in 11 cases: management of infection with maintenance of internal fixation. In 23 cases the implant material had to be removed. Nevertheless the infection was eliminated in all these patients without exception. The following risk factors for mandatory implant removal were evaluated: diabetes, arteriosclerosis, alcoholism, nicotine. This revision concept helps in the management of acute postoperative osteitis following ORIF in fracture treatment and in avoiding the development of chronic osteitis.

Adolescent↗
PubMed1994

Dose-related pattern of sinusoidal leukocyte adhesion in sublobular regions of the liver after systemic endotoxin challenge in the rat.

The unique arrangement of large numbers of fixed tissue macrophages, endothelial, and parenchymal cells along hepatic sinusoids as well as their key role in the acute phase response makes the liver a primary target organ in endotoxemia. Pathogenesis of hepatic failure in endotoxemia is incompletely understood, but microcirculatory failure as well as leukocyte-endothelial interaction in response to inflammatory mediators may relate to it. Using intravital fluorescence microscopy, sinusoidal widths, leukocyte flow velocity, and sublobular leukocyte (white blood cell (WBC)) adhesion characteristics 1 h after randomized intravenous application of 0, 0.1, 1, or 5 mg/kg b.w. Escherichia coli endotoxin O 111 B4 (ETX) were evaluated in female Sprague-Dawley rats (n = 6-8/group). Whereas the bolus injection of ETX caused only minor concurrent macrohemodynamic effects, a significant increase of permanent WBC adhesion especially in periportal areas (0 mg, 2.1 +/- 0.7%; 0.1 mg, 16.2 +/- 3.6%**; 1 mg, 15.5 +/- 1.0%**; 5 mg, 13.2 +/- 2.3%* (**p < .01, *p < .05, compared to vehicle)) was found in all groups 60 min after ETX challenge. In contrast, an increase of WBC margination in midzonal and pericentral regions was only seen with the higher doses of 1 or 5 mg/kg ETX, respectively. The sublobular pattern of WBC margination is consistent with the concept of regulation of WBC adhesion by inflammatory mediators released by lipopolysaccharide-stimulated Kupffer cells in vivo. We propose that overwhelming the detoxifying capacity of predominantly periportally located Kupffer cells with large amounts of ETX may lead to activation of pericentral-located resting macrophages paralleled by a rise of adhering leukocytes.

Animals↗
PubMed1994

Intestinal ischemia: reperfusion-mediated increase in hydroxyl free radical formation as reported by salicylate hydroxylation.

Oxygen free radicals may play a pivotal role in the development of the shock-induced inflammatory response syndrome. Hydroxyl free radicals (.OH) react with salicylate (SA) to form 2,5- and 2,3-dihydroxybenzoic acid (DHBA) products. We utilized salicylate hydroxylation to investigate .OH formation during intestinal ischemia/reperfusion injury in male Sprague-Dawley rats. After administering salicylate, the superior mesenteric artery was occluded for 45 min and then allowed to reperfuse for 90 min after declamping. No significant changes in plasma 2,3- and 2,5-DHBA/SA ratios were observed in sham-operated or in animals given intestinal ischemia without reperfusion. A significant increase (p < .05) in arterial, venous, and portal venous 2,5-DHBA/SA ratios occurred 5 min after reperfusion. This increase was prevented by allopurinol as well as by dimethylthiourea (.OH scavenger) pretreatment. 2,3-DHBA was significantly increased (p < .05) in venous and portal venous blood after 30 min of reperfusion, but was not detectable in plasma of allopurinol- and dimethylthiourea-treated rats. These results indicate that hydroxyl free radical formation as reported by SA hydroxylation appears to be important in intestinal ischemia/reperfusion-related tissue injury.

Animals↗
PubMed1993

Value of superoxide dismutase for prevention of multiple organ failure after multiple trauma.

In a prospective, randomized trial, recombinant human superoxide dismutase (rhSOD, 3000 mg/day, Grünenthal, Aachen, Germany) or placebo was given intravenously during 5 days after multiple injuries (Injury Severity Score [ISS] > or = 27; 24 patients). Manifestation of multiple organ failure (MOF) and posttraumatic inflammatory response were evaluated over 14 days. No side effects were noted by continuous infusion of rhSOD, which allowed high SOD plasma levels (24.77 +/- 9.43 mg/L) compared with controls (0.03 +/- 0.02 mg/L). Multiple organ failure was attenuated by rhSOD treatment in respect to cardiovascular and pulmonary functions. Additionally, intensive care therapy was shortened from 30 days (Q25: 15; Q75: 37) to 21 days (Q25: 12; Q75: 41). A secondary increase of inflammatory mediators (e.g., C-reactive protein, polymorphonuclear [PMN]-elastase, phospholipase A2), as observed at the end of the first week in the placebo group, was reduced by rhSOD therapy. The results reveal an attenuation of organ failure after trauma, most likely by decreasing the release of inflammatory mediators and reduction of leukocyte-mediated organ injury. These preliminary results, while promising, need to be confirmed in a larger number of patients.

Acute-Phase Reaction↗