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Biomedical subjects

Detlev Erdmann

Publications and source records attributed to Detlev Erdmann.

7 recordsLinked to original sources

Soft tissue coverage in devastating hand injuries.

Plastic surgical therapy of mutilating hand injuries represents a multifaceted task to the hand surgeon, where considerations about indication, timing, and structure of the soft tissue coverage play a major role in reconstruction. The concept of early primary reconstruction (including emergency procedures) and fast rehabilitation not only demands thoughtful tissue preparation but also mastering of a bandwidth of plastic surgical techniques. Systematic algorithms based on the reconstructive ladder help in decision making in the complexity of soft tissue coverage but have to be adjusted to the individual case profile. General considerations and strategic planning are explained and illustrated by three clinical cases.

Adult↗

Vascular endothelial growth factor expression in pig latissimus dorsi myocutaneous flaps after ischemia reperfusion injury.

Exogenous administration of vascular endothelial growth factor (VEGF) improves long-term viability of myocutaneous flaps. However, endogenous expression of this substance in flaps following ischemia-reperfusion injury has not been reported previously. Endogenous production of VEGF was measured in myocutaneous pig latissimus dorsi flaps after ischemia-reperfusion injury. Latissimus dorsi myocutaneous flaps (15 x 10 cm) were simultaneously elevated bilaterally in six Yorkshire-type male pigs (25 kg). Before elevation, three flap zones (5 x 10 cm) were marked according to their distance from the vascular pedicle. After isolation of the vascular pedicle, ischemia-reperfusion injury was induced in one flap by occlusion of the thoracodorsal artery and vein for 4 hours, followed by 2 hours of reperfusion. The contralateral flap served as a control. Perfusion in each zone was monitored by laser Doppler flowmetry at baseline, during ischemia, and during reperfusion. At the end of the protocol, skin and muscle biopsies of each flap zone and adjacent tissues were obtained for later determination of VEGF protein levels. VEGF concentrations were quantified using the Quantikine human VEGF immunoassay. Skin perfusion was similar among all flap zones before surgery. Flow fell in all flaps immediately after flap elevation. After 4 hours of ischemia, blood flow in the ischemic flaps was significantly decreased (p < 0.05) compared with nonischemic control flaps. After 2 hours of reperfusion, flow in ischemic flap skin recovered to levels similar to those in control flaps. VEGF protein concentrations in muscle tissue exceeded concentrations in skin and decreased from zones 2 to 3 in control and ischemic flaps. No significant differences in VEGF concentrations between ischemic and control muscle zones were observed. However, the concentration of VEGF in all muscle zones was significantly higher (p < 0.05) than muscle adjacent to the flap. Concentrations in skin zones 1 and 2 were significantly higher (p < 0.05) in ischemic flaps than in control flaps, but levels in zone 3 (most ischemic flaps) showed no significant difference.

Animals↗

A realistic complication analysis of 70 sural artery flaps in a multimorbid patient group.

The popularity of the sural artery flap has increased markedly throughout the years, and favorable results are reported almost uniformly. Previous publications have mainly presented results of small groups and of predominantly younger patients with posttraumatic defects, or they have reported technical modifications of the sural artery flap. The authors have increasingly used the reversed sural artery flap in a high-risk, critically multimorbid, and older patient population, and in contrast to the results of other authors, a considerable necrosis rate of 36 percent was seen. For the first time, a detailed, critical, retrospective complication analysis of 70 sural artery flaps is presented. The results reveal the following risk factors, which can potentially impair successful defect coverage and thus contribute to flap complications: concomitant diseases, particularly diabetes mellitus; peripheral arterial disease or venous insufficiency, which increase the risk of flap necrosis five-fold to six-fold; and patient age of over 40 years, because of an increased rate of comorbidity, underlying osteomyelitis, and the use of a tight subcutaneous tunnel. However, age alone did not seem to represent a risk factor by itself. Given the results of the analysis, the operative procedure was altered, as follows. In cases in which a lesser saphenous vein cannot be found, a delay procedure is recommended, or the flap is not utilized. In addition, an external fixation device seems to facilitate postoperative care markedly without adding specific complications; it is recommended in most patients. This analysis emphasizes specific risk factors that result in higher complication rates of the sural artery flap, and it leads to more realistic and appropriate expectations for this flap.

Adult↗

Delay in unipedicled TRAM flap reconstruction of the breast: a review of 76 consecutive cases.

Since its introduction in 1982, the transverse rectus abdominis musculocutaneous (TRAM) flap has become the standard therapy in autogenous breast reconstruction. A lower rate of partial flap (fat) necrosis is associated with microvascular free-flap transfer compared with the conventional (unipedicled) TRAM flap because of its potentially improved blood supply. A TRAM flap delay before flap transfer has been advocated, especially in a high-risk patient population (obesity, history of cigarette smoking, radiation therapy, or abdominal scar). The authors reviewed a series of 76 consecutive delayed unipedicled TRAM flap breast reconstructions during a 5-year period. Data were analyzed with respect to type of procedure and time of delay, overall outcome, general surgical complications, flap-related (specific) complications (partial or complete flap loss), and patient satisfaction. Seventy-six unilateral breast reconstructions using the unipedicled TRAM flap were performed between 1995 and 2000 in 76 patients (mean age, 47.4 years). Fifty-four flaps were performed as immediate reconstructions, and 22 as secondary procedures. Seventy-two flaps were based on the contralateral pedicle, and four flaps were based on an ipsilateral pedicle. In all cases, a flap delay consisted of ligature of both deep inferior epigastric arteries and veins, accessed from an inferior flap incision down to the fascia, with a mean of 13.9 days before the flap transfer. No acute flap take-back procedure had to be performed. There was no complete flap loss, and breast reconstruction was achieved in all cases. In five cases (6.6 percent), a partial (fat) flap necrosis occurred. Interestingly, the majority of these cases (four of five) were secondary breast reconstructions. In addition, of the five patients who had partial flap necrosis, four had a history of smoking, two received radiation therapy, three received chemotherapy, and three patients were obese (body mass index greater than or equal to 30) or overweight (body mass index greater than or equal to 25). In three cases, an early surgical complication (two wound infections at the flap interface and one at the donor site) occurred. One patient developed a deep vein thrombosis. Five patients developed secondary ventral hernias necessitating repair (6.6 percent). Forty-one patients underwent secondary nipple-areola reconstruction. In 19 patients of this group, a secondary procedure (e.g., scar revision, limited liposuction, and/or excision of contour deformities) was simultaneously performed. A survey of patient satisfaction was performed using a modified SF-36 questionnaire. Fifty-one patients participated (67 percent). The overall satisfaction was very high and 51 patients reported that they would recommend the procedure to others (100 percent). Multiple factors such as patient selection, surgical expertise, and preoperative and postoperative management contribute to the success of any type of autogenous breast reconstruction. However, rare partial and absent complete flap necrosis in the authors' series may be attributable to the flap delay. A low morbidity rate and short hospital stay may become increasingly relevant, with limited structural and financial resources in the future. Therefore, the delayed unipedicled TRAM flap should be regarded as a valuable option in attempted breast reconstruction using autogenous tissue in both a high-risk and the general patient population.

Body Mass Index↗

Microsurgical free flap transfer to amputation sites: indications and results.

A series of microsurgical free flap reconstructions to amputation stumps of the upper as well as the lower extremities was reviewed in 7 male and 2 female patients. Indications included preservation of length after trauma in 6 patients and cure of local infection in 2 patients. In 1 patient an extensive defect after resection of a recurrent shoulder sarcoma required use of a complete arm fillet free flap for tumor reconstruction. Microvascular free flaps used included four scapular flaps, two fillet flaps from the amputated extremity, one anterolateral thigh flap, and one lateral arm flap. Seven of 9 patients were fitted with a prosthesis and underwent occupational therapy resulting in ambulatory and improved functional status. Microvascular reconstruction is indicated in emergency settings as well as for elective reconstruction of amputation sites. Using uninjured "spare parts" of the amputated extremity should be considered. Elective reconstruction is performed preferably with free flaps based on the subscapular vascular system.

Adolescent↗

Transcardiopulmonary vs pulmonary arterial thermodilution methods for hemodynamic monitoring of burned patients.

The objective of this study was to validate a new method of transcardiopulmonary thermodilution for assessment of cardiac index (CI), stroke volume index (SVI), systemic vascular resistance index (SVRI) and additional parameters such as intrathoracic blood volume index and extravascular lung water index (EVLWI) by comparison with conventional pulmonary artery catheter values in a severely burned population. The pulmonary artery measurements were performed continuously with the Vigilance system, and the transcardiopulmonary thermodilution with the PiCCO(R) system. One hundred thirteen measurements with each system on up to six consecutive days were taken in 14 severely burned patients (average TBSA, 49.6%; average ABSI, 10.3), aged 21 to 61 years (mean, 42.2 years) and compared intraindividually. An excellent correlation between the two methods was shown for CI (r = 0.80) and its derived parameters SVI and SVRI in states of low to normal cardiac output. The correlation was poor for cardiac indices greater then 5.5 up to their maximum values (r = 0.46). No correlation between index of oxygenation (PaO2/FiO2) vs EVLW I was observed. There was no difference between survivors and nonsurvivors, and between patients with and without inhalation injury in EVLWI. The method of transcardiopulmonary thermodilution is suitable to assess SVI, CI and SVRI under the special pathophysiologic condition of a major burn for low to normal cardiac output states. It is less reliable when cardiac output is high. The lower cost and less invasive nature are the advantages of the system compared with use of the pulmonary artery catheter. The role of intrathoracic blood volume index and EVLWI in cardiopulmonary monitoring of severely burned patients remains to be further determined.

Adult↗