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Biomedical subjects

H G Machens

Publications and source records attributed to H G Machens.

At least 37 records · Page 2Linked to original sources
PubMed1998

Persistence of pedicle blood flow up to 10 years after free musculocutaneous tissue transfer.

The hypothesis of whether or not flap perfusion remains persistent through its vascular pedicle up to 10 years after free tissue transfer was tested. Since 1982, more than 1,000 free tissue transfers have been performed at this institution. Of these, 40 patients were selected with comparable posttraumatic soft-tissue defects of the lower leg and surgical repair by a latissimus dorsi myocutaneous free flap. All patients had a postoperative course free of complications. Measurements of flap perfusion were started in groups 1 through 4 (each 10 patients) 3 to 5 weeks, 5 to 7 months, 4 to 6 years, and 8 to 10 years after free tissue transfer, respectively. Quantitative measurements of local flap perfusion were performed by means of the hydrogen clearance technique (Ameda, Switzerland) at definite sites intracutaneously and subcutaneously within the flap's skin paddle as well as in the adjacent intracutaneous and subcutaneous skin of the surrounding soft tissue. Simultaneously, the vascular pedicle of the flap was visualized by a duplex scanner (Toshiba, Japan). In each group nine measurements were performed before (phase A), during (phase B), and after closing the pedicle (phase C) by manual compression. Each measurement took about 10 minutes. Statistical evaluation of the obtained values was achieved by the Mann-Whitney U test and the Wilcoxon signed rank test. Local flap perfusion showed no statistical differences for phase A and C in all four groups of patients. In phase B, however, a statistically highly significant (p < 0.01) absence of local flap perfusion was registered in all four groups at the site of the flap's skin paddle. No statistically significant alterations of intracutaneous and subcutaneous blood flow was found in the surrounding soft tissue. In our clinical-experimental setting, flap perfusion persisted by means of its vascular pedicle even 10 years after free tissue transfer. Our findings support the importance of an intact vascular pedicle for permanent flap survival after free tissue transfer.

Adult↗
PubMed1998

[Functional angiogenesis induction in epigastric islet flap rat model after genetic modification of fibroblasts].

Gene therapy was tested for inducing functional angiogenesis in the superficial rat epigastric island flap to allow earlier pedicle division. Autologous rat fibroblasts were grown, harvested, cultured and retrovirally transfected to produce PDGF-AA, an angiogenetically active protein. Stable gene expression was monitored by PDGF-AA ELISA. 180 animals were divided into 3 groups (I-III) and a bilateral flap created in each animal. In all experiments, the rightsided flap was subjected to experimental treatment and the left-sided flap served as control (1 ml saline 0.9%). During flap elevation, group I received 5 x 10(6) GMFB (genetically modified fibroblasts) plus 1 ml DMEM as medium. Group II was treated with 5 x 10(6) NMFB (non modified fibroblasts) plus 1 ml medium and group III received 1 ml medium alone. The flaps were sutured back and the vascular pedicle was bilaterally ligated and divided in each 10 animals during the following 6 days. 7 days later, the flaps were harvested, the amount of necrosis measured and histologically examined. The GMFB produced up the 560-times more PDGF-AA than the NMFB, measured by ELISA. The GMFB-treated flaps tolerated surgical division of the vascular pedicle significantly earlier than groups II and III. Histologically, fibroblasts persisted in all flaps of groups I and II without major inflammatory reaction. In all GMFB-treated flaps, massive angiogenesis could be demonstrated. By means of retroviral gene transfer autologous rat fibroblasts can be genetically modified for stable expression of the PDGF-A gene to produce high amounts of PDGF-AA, which is angiogenetically active. After injection into the panniculus carnosus, these cells induce functional angiogenesis to permit earlier division of the vascular pedicle in this flap model.

Animals↗
PubMed1998

[Does tissue perfusion after free microvascular tissue transplantation stay autonomous?].

In a prospective study including 60 patients after free latissimus dorsi transfer (FLDT) to the lower leg, we found persistence of pedicle blood flow up to 10 years postoperatively. After uncomplicated FLDT the pedicle supported the flap in all cases, whereas after complicated FLDT (hematoma, thrombosis, infection) we found only 50% of all flaps autonomously perfused by the vascular pedicle.

Adolescent↗
PubMed1997

[Intrabronchial surfactant administration in inhalation trauma of severely burned patients with ARDS. Initial case reports].

Damage to the respiratory system caused by inhalation of toxic products of combustion and the subsequent development of adult respiratory distress syndrome (ARDS) are the main lethal factors in burns patients. Treatment with exogenous surfactant is one of the therapeutic options. However, no clinical reports have yet been published about this therapy. We report on two patients with burn injuries of second to third degree affecting 42% and 48% respectively of the total body surface plus inhalation injury complicated by ARDS. Both patients were treated with bovine surfactant (Alveofact). The therapeutic effects on oxygenation and pulmonary function were monitored. Intrabronchial application of surfactant by bronchoscopy during exhaustive conventional mechanical ventilation resulted in improved gas exchange with an increase in arterial O2 pressure (paO2); inspired O2 concentration (FiO2) was lowered and there was an improvement in lung compliance. Both patients survived this critical situation. We conclude that treatment with exogenous surfactant in postburn victims with ARDS is a promising therapeutic approach to improve the survival rate of these high-risk patients.

Adult↗
PubMed1997

[Enchondroma of the hand. Clinical evaluation study of diagnosis, surgery and functional outcome].

Enchondroma are benign cartilaginous tumors and are localized most often at the site of the phalanges. Between 1982 and 1993 73 patients with monostotic enchondroma and 5 patients with polyostotic enchondroma were operated at our clinic. Clinical signs of monostotic tumors were pathological fracture (38.4%), pain or swelling. Eleven percent of cases were accidental findings. Surgical treatment was performed by complete removal of the tumors and filling the bone cavity with autologous spongiosa taken from the pelvic bones, the elbow, or the radius. Three patients (4.1%) had to be operated a second time due to wound infections and hematoma. In one case Sudeck's dystrophy was diagnosed. One patient (1.4%) developed a recurrent tumor. Our follow-up examination of 65 patients showed that 77% of the patients with monostotic enchondroma achieve very good or good functional long-term results after this operation, but only 40% of the patients with polyostotic enchondroma.

Bone Neoplasms↗
PubMed1997

Postoperative blood flow monitoring after free-tissue transfer by means of the hydrogen clearance technique.

The hydrogen clearance technique was introduced for monitoring postoperative blood flow after free-tissue transfer in this prospective clinical study. This technique allows unlimited repeatable quantitative measurements of tissue blood flow in milliliters per minute per 100 gm of tissue at any site including buried flaps. In this study a real-time blood flow measuring system (Ameflow, Ameda, Switzerland) was employed. Two thousand eight hundred and twenty-three blood flow measurements were carried out on 72 free-tissue transfers, which were performed on 71 patients. Nine of these 72 flaps showed vascular complications (12.5 percent), including arterial thrombosis in 6.9 percent (n = 5), hematoma in 4.2 percent (n = 3), and venous thrombosis in 1.4 percent (n = 1). Complications as well as uneventful postoperative cases were monitored correctly by the hydrogen clearance technique in all cases, reaching sensitivity and specificity values of 1.0 for this technique in our study. Furthermore, all complications could be detected earlier by the hydrogen clearance technique than by clinical monitoring alone, which allowed flap salvation in 7 of 9 cases and a resulting permanent failure rate of free-tissue transfer of 2.8 percent (n = 2). From our data we conclude that the hydrogen clearance technique is a promising tool for postoperative blood flow monitoring after free-tissue transfer. For experimental pathophysiologic and pharmacologic studies of tissue blood flow in flaps, further evaluation of our measuring device including comparative studies with other established techniques is highly recommended.

Adolescent↗
PubMed1997

The fasciocutaneous supraclavicular artery island flap for releasing postburn mentosternal contractures.

Mentosternal contractures represent a surgical challenge to the plastic and reconstructive surgeon. We add the supraclavicular artery island flap to the armamentarium of surgical procedures to improve the function and cosmesis of disfigured patients. Since July of 1994, the supraclavicular artery island flap has been used at our institution for releasing postburn mentosternal contractures in eight patients. The flap was planned to be 4 to 10 cm in width and 20 to 30 cm in length with the supraclavicular vessels running axially. All donor defects could be closed primarily without significant postoperative complications in seven of the eight patients. All flaps healed primarily, achieving a good functional result by complete removal of contracting scar tissue for all patients; one donor site healed by secondary intention. We found the supraclavicular artery island flap both reliable and safe for immediate resurfacing after resection of cervical scars. The anatomy, operative procedure, and postoperative results of the supraclavicular artery island flap are outlined in this paper.

Adult↗
PubMed1997

[Analysis of cost measures in treatment of severely burned patients].

An analysis of costs and profit and an evaluation of the different cost parameters was performed in our burn centre, which treated 50-80 patients per year between 1991 and 1995. The cost-profit relationship (costs 3.7-4.6 million DM/year, profit 3.8-5.0 million DM/year) is balanced. The main cost parameters are staff costs (1.3-1.9 million DM/year), costs for medical treatment (1.5-1.8 million DM/year), and costs for internal services (0.6-0.9 million DM/year).

Burn Units↗
PubMed1996

True aneurysms of the palmar arch of the hand: a report of two cases.

We report on two cases of true aneurysms of the palmar arch, both of which were post-traumatic. One was due to repetitive blunt trauma and the other to a glass cut wound. Both aneurysms were detected clinically as pulsating masses without functional disorders. The presence of elastic fibres and smooth muscle in the aneurysm wall proved it to be a true aneurysm. Both aneurysms were excised and replaced by a vein graft from the foot.

Adult↗
PubMed1996

Technetium-99m human immunoglobulin (HIG): a new substance for scintigraphic detection of bone and joint infections.

Technetium (99m-Tc)-labelled, polyclonal human immunoglobulin (HIG) has been described as a new agent to detect local infection and inflammation. In this study, we tested 99m-Tc HIG in 55 patients with suspected chronic (n = 42) and acute (n = 13) skeletal infection. Diagnosis was proven operatively (n = 44) and clinically (n = 11), including microbiological culture tests (n = 46). A gamma camera scan was performed 4 and 24 hours after I.v. injection of 500 MBq 99m-Tc-HIG. 99m-Tc-HIG scanning achieved a sensitivity of 91% and a specificity of 93%. We found one false negative and five false positive scintigraphic results in 55 patients. No clinical or biochemical side effects were encountered after 99m-Tc-HIG injection. We recommend this technique especially for localisation of low-grade, chronic osteomyelitis. The mechanisms and kinetics of 99m-Tc-HIG, however, are worth investigating more extensively.

Acute Disease↗
PubMed1996

[Model for a computer-assisted quality assurance system in burn intensive care].

The prerequisites for an integrated quality management system for hospitals were developed as a result of considerations regarding the necessity of an appropriate quality-assurance system for the intensive care sector. The basis for a dynamic quality-assurance system on the documentational level is a comprehensive data base containing patient files unlimited in terms of time and data technology. The necessary hardware and software structure will be provided by consistent application of a client-server architecture. Permanent surveillance of existing quality objectives within the scope of an economic close-loop system requires a system with flexible query mechanisms. Informational data access from all hierarchical level within the hospital organization is facilitated by the data warehouse concept, a data base system with subject-oriented, integrated, time-variable, and persistent data.

Burn Units↗
PubMed1996

[Treatment of mentosternal contractures by flap-plasty].

Mentosternal contractures still represent a surgical challenge due to their exposed location. They require early operative treatment for both functional as well as aesthetic reasons. Careful clinical examination of scar location and traction forces both in the resting and functional, moving state including proper evaluation of the surrounding soft tissue is mandatory for exact preoperative planning of the reconstructive surgical procedure required. In general, the technically most feasible operation is favoured, if functional and aesthetic results are good and the postoperative risk of recurrent mentosternal contractures is low. Between 1987 and 1994, 21 patients with cervical, mentosternal and mentothoracic contractures underwent operative procedures at our clinic. Eight patients underwent a surgical reconstruction with local flaps and 13 patients received a free microvascularized flap.

Adolescent↗
PubMed1996

[Budget analysis in a burn center for severely burned patients].

The treatment of patients with severe burn injuries is expensive and belongs in the hands of specialized burn centres. In our burn centre 257 patients were treated from 1991 to June 1995 (between 50 and 60 patients per year except for 1993 with 77 patients). Patients were evaluated according to the ABSI score (mean 7) and had mortality of around 15%. The costs range between 3.7 and 4.8 million DM per year, the profit lies in the same range. The costs are divided into staff costs (1.4-1.8 million DM per year), costs for medical treatment (1.5-1.9 million DM per year) and costs for internal services (600,000-900,000 DM per year) such as laboratory examinations (247,000-386,000 DM per year) and blood bank (100,000-215,000 DM per year), the main factors in this category. The different fields of costs and profit are compared in this analysis. Possible ways of reducing costs are pointed out, and the question of effectiveness of therapy is discussed. Conclusions from this analysis are limited by the individuality of each case with different clinical courses, the great number of influencing factors and the comparably small numbers of patients.

Budgets↗
PubMed1996

[Bilateral biceps replacement-plasty by transposition of the latissimus dorsi muscle in arthrogryposis multiplex congenita. A case report].

The case of a four-year old girl with arthrogryposis multiplex congenita is reported. Primary clinical examination revealed bilateral passive elbow flexion only 0-20-70 without active elbow flexion. A two-stage operative procedure was chosen for both sides. At first an elbow arthrolysis was performed with subsequent intensive physiotherapy. In a second session we performed a bipolar transposition of the latissimus dorsi as a myocutaneous flap. The patient was first operated on the left and afterwards on the right side. By this procedure, the patient achieved a significant improvement of both passive and active elbow flexion mobility. The range of active motion was 0-30-90 and 0-40-90 degrees.

Arthrogryposis↗
PubMed1996

[Surgical prevention of post-traumatic infection by immediate necrectomy of burn wounds].

Sepsis is the commonest cause of death following burn injuries. The main source of the bacteria which cause the onset of sepsis is the burn wound itself. We evaluated the question of whether immediate necrectomy versus early necrectomy leads to a decrease in septic complications, as well as posttraumatic lethality. We evaluated 66 patients, 33 of whom underwent immediate necrectomy (i.e., within the first 3 days posttraumatically, group 1); the remaining 33 patients underwent necrectomy in the early posttraumatic phase (from the fourth posttraumatic day, group 2). Following immediate necrectomy (group 1), septic complications developed in 12.1%, as compared to 33.3% in group 2 (p < 0.01). Lathality was significantly reduced in group 1 with 9.1% compared to 21.2% in group 2 (p < 0.01). In this study it was demonstrated that immediate necrectomy versus early necrectomy in young patients leads to a significant decrease of septic complications and lethality following burn injury.

Adult↗
PubMed1995

Vascular complications after free tissue transfer.

Between 1981 and 1992, 631 cases of free tissue transfer were operated on at our clinic. Of these cases, 489 were reviewed for vascular complications. The aim of the study was to evaluate retrospectively possible correlations between complications and operative faults. Vascular complications occurred in 16%. By immediate operative revision 50% of the cases with a vascular complication could be salvaged. In general, earlier diagnosis and treatment of vascular complications after free tissue transfer prompted a higher success rate of the surgical revision.

Anastomosis, Surgical↗
PubMed1995

Measurements of tissue blood flow by the hydrogen clearance technique (HCT): a comparative study including laser Doppler flowmetry (LDF) and the Erlangen micro-lightguide spectrophotometer (EMPHO).

The purpose of this study was to compare the hydrogen clearance technique (HCT) with two different, well-established techniques, i.e., the laser Doppler flowmetry (LDF) and the Erlangen micro-lightguide spectrophotometer (EMPHO), for tissue blood flow measurements in an experimental setting. For the animal experiments, we chose a rat model for arterial and venous flap thrombosis, using the epigastric groin flap. Forty male dark Aguty rats were included in the study. The animals were divided into eight groups, each with a different vascular thrombotic model. HCT was used to collect 1,467 measurements, and 2,934 graphs were recorded; 27 measurements (54 graphs) had to be discarded due to faulty electrode placements and electronic noise. In 19 of the 27 discarded measurements the cause of failure was moving of the awaking animal with disruption of the decay signal. The LDF and EMPHO measurements were performed continuously during each measuring phase. Simple and multiple linear regression and paired t-tests were used to compare the three techniques. The reproducibility of registered blood flow values in phases 1, 3, 6 and 7 varied between 7.8% and 13.6% which is in about the same range as LDF and EMPHO. We could not find a significant difference between the three techniques in this regard. The correlation coefficient for HCT and LDF was r = 0.89. For HCT and EMPHO we found r = 0.67. Sensitivity and specificity values for HCT were both 1.0 in detecting arterial and venous flap thrombosis; for LDF we found values of 0.89 and 0.92, respectively. Sensitivity and specificity values for EMPHO were 0.92 and 0.95, respectively. After careful evaluation of three different techniques (HCT, LDF, and EMPHO) for measurements of local tissue blood flow we came to the conclusion that HCT must be favoured as a reliable tool for quantitative measurement of local tissue blood flow and early diagnosis of arterial and venous flap thrombosis.

Animals↗