Frank Siemers

The clinical use of artificial nerve conduits for digital nerve repair: a prospective cohort study and literature review.

Tubulization as an alternative to autologous nerve grafting successfully bridges relatively short nerve gaps. Digital nerve lesions are ideal for clinical outcome studies, but only a few data have been published so far. We are presenting our clinical experiences based on a review of the outcome and techniques in the current literature. Fifteen digital nerve lesions in 14 patients have been overcome by interpositional grafting of a hollow collagen I conduit. A follow-up of 12 months could be guaranteed in 12 cases. The mean nerve gap was 12.5 +/- 3.7 mm. Four out of 12 patients, assessed 12 months postoperatively, showed excellent sensibility (S4). Five patients achieved good sensibility, one poor, and two no sensibility. Our results confirm tubulization as one possible technique in nerve reconstruction. However, the indication has to be set carefully, and the operation still requires solid microsurgical skills, especially for proper handling and debridement of the severed nerve endings.

Angiogenic Effects of Injected VEGF165 and sVEGFR-1 (sFLT-1) in a Rat Flap Model

BACKGROUND Injections of single-dose vascular endothelial growth factor (VEGF)(165) have been advocated as a therapeutic tool for angiogenesis in ischemic flaps. We challenged this thesis by employing both VEGF(165) and vascular endothelial growth factor receptor-1 (VEGFR-1) (for competitive inhibition of VEGF signal transduction) in different experimental settings of an ischemic rat flap model. MATERIAL AND METHODS 80 isogenic rats were divided in two groups of 40 animals (groups 1A-1D and 2A-2D). The ischemic target was a 7 x 7-cm epigastric island flap, based on the right inferior epigastric pedicle. Group 1 received flap treatment 1 week prior to flap elevation by test substance injection into its flap panniculus carnosus: 1 ml NaCl 0.9% (1A), 1 ml Dulbeccos modified Eagles medium (1B), 1.0 microg VEGF(165) (1C), and 10 microg sFLT-1 with 1.0 microg VEGF(165) (1D). sFLT-1 is a soluble receptor for VEGF and is able to prevent VEGF signaling through the cell surface receptor. Group 2 had the same flap treatment at the day of flap elevation. RESULTS In group 1C we found the most vital flap tissue, without reaching significance. Compared with group 1D, however, significantly more flap tissue maintained vital. In groups 2A-2D, no significant results were found with respect to flap survival. CONCLUSIONS Local application of single-dose VEGF(165) 1 week prior to ischemia dose not have significant clinical angiogenic effects. In this experimental setting, VEGF(165)-induced angiogenic effects can be significantly inhibited by adding sFLT1 in vivo. A single-dose of VEGF(165) under ischemic conditions causes no significantly better flap survival in this model.

Flap perfusion after free musculocutaneous tissue transfer: the impact of postoperative complications.

In a previous study, the authors found persistence of pedicle blood flow up to 10 years after uncomplicated free latissimus dorsi transfer. In this study, the impact of postoperative complications (hematoma, thrombosis, infection) and successful surgical revision was tested. Since 1982, more than 1200 free tissue transfers have been performed at the authors’ institution (Hannover Medical School). Of these, the authors selected two groups of 30 patients each who had received a free latissimus dorsi transfer to the lower leg without microsurgical nerve coaptation for wound coverage. All patients included in this study were carefully selected for clinical homogeneity, with one difference: group I comprised patients who had no postoperative complications after free latissimus dorsi transfer. Group II included only patients with major postoperative complications after the procedure. All flaps in group II survived after successful surgical revision. The arteries, which nourished the lower leg, were visualized and documented by means of a duplex scanner in both groups. Three different time intervals were chosen for measurements of blood flow: 4 to 6 months (groups I.I and II.I), 4 to 6 years (groups I.II and II.II), and 8 to 10 years (groups I.III and II.III). Quantitative measurements of local flap perfusion in milliliters per minute per 100 g tissue were performed by means of the hydrogen clearance technique. In each patient, a total of nine measurements was performed in three phases: phase A, before closing the vascular pedicle by manual compression (n = 3); phase B, with a closed pedicle (n = 3); and phase C, after releasing the vascular pedicle from manual compression (n = 3). Each measurement took approximately 10 minutes. One hundred percent closure of each pedicle in phase B was confirmed by the duplex scanner. Furthermore, all patients were monitored both clinically and by means of the hydrogen clearance technique during phase B for adequate blood supply to the lower leg. Lower leg perfusion showed no statistical differences for phases A, B, and C in all groups of patients. In group I, no statistical differences in local flap perfusion were encountered for phases A and C. In phase B, however, a statistically significant (p < 0.01) complete extinction of local flap perfusion was registered in all patients of group I at the site of the flap’s skin paddle. In group II, however, persistent flap perfusion was registered during phase B in up to 50 percent of cases in one subgroup (II.III). No statistically significant alterations of local blood flow were registered in the surrounding tissue of group II during phases A, B, and C. Patients with thrombosis of the venous anastomosis (n = 7) seemed to have the highest incidence of loss of autonomous blood supply through the vascular pedicle (5 out of 11 cases). No inconstant results were found during the repetitive measurements (n = 3) for each patient in each phase. After uncomplicated free tissue transfer, the flap’s intact vascular pedicle seems to play an important role in permanent flap survival up to 10 years after the procedure. Postoperative complications after free tissue transfer with successful surgical revision, especially venous thrombosis of the vascular anastomosis, may lead to loss of vascular flap autonomy over time.

A multi-center study on the regenerative effects of erythropoietin in burn and scalding injuries: study protocol for a randomized controlled trial

BackgroundAlthough it was initially assumed that erythropoietin (EPO) was a hormone that only affected erythropoiesis, it has now been proposed that EPO plays an additional key role in the regulation of acute and chronic tissue damage.Via the inhibition of inflammatory reactions and of apoptosis, stem cell recruitment, advancement of angiogenesis and growth factor release, EPO enhances healing and thus restitutio ad integrum after trauma. Human skin contains EPO receptors and is able to synthesize EPO. We therefore hypothesize that EPO is able to optimize wound healing in thermally injured patients.Methods/DesignThis is a large, prospective, randomized, double-blind, multi-center study, funded by the German Federal Ministry of Education and Research, and fully approved by the designated ethics committee. The trial, which is to investigate the effects of EPO in severely burned patients, is in its recruitment phase and is being carried out in 13 German burn care centers. A total of 150 patients are to be enrolled to receive study medication every other day for 21 days (EPO 150 IU/kg body weight or placebo). A follow-up of one year is planned. The primary endpoint of this study is the time until complete re-epithelialization of a defined skin graft donor site is reached. Furthermore, clinical parameters such as wound healing, scar formation (using the Vancouver scar scale), laboratory values, quality of life (SF-36), angiogenic effects, and gene- and protein-expression patterns are to be determined. The results will be carefully evaluated for gender differences.DiscussionWe are seeking new insights into the mechanisms of wound healing in thermally injured patients and more detailed information about the role EPO plays, specifically in these complex interactions. We additionally expect that the biomimetic effects of EPO will be useful in the treatment of acute thermal dermal injuries.Trial registrationEudraCT Number: 2006-002886-38, Protocol Number: 0506, ISRCT Number: http://controlled-trials.com/ISRCTN95777824/ISRCTN95777824.

Nerve injuries of the upper extremity-expected outcome and clinical examination.

Nerve injuries are common in trauma surgery and appear more frequently if the upper extremity is affected. The aim of this study is to estimate possible predictors of the outcome after nerve injury of the upper extremity and to demonstrate feasible tools to follow up postoperative nerve regeneration for the daily clinical practice. During January 2000 until December 2004, a total of 372 nerve lesions of the upper extremity have been treated in our clinic. Patients age, site of nerve lesion, concomitant injuries, and the timing of surgical repair could be outlined to be significant predictors for clinical outcome. Digital nerve lesions showed the best regenerative capacity. Most predictors of clinical outcome such as patients age, concomitant injuries, and site of lesion cannot be influenced. But knowing the predictors helps specify the prognosis of nerve regeneration. For the daily clinical practice, static two-point discrimination, location of Tinels sign, and grip strength measurement seem to be fast and reproducible tools to follow up nerve regeneration at the upper extremity.

Hibernoma-case report and literature review.

Hibernoma is an uncommon benign fatty tumor that arises from the vestiges of fetal brown fat. We present a case report of a hibernoma of the back in a symptomatic 42-year-old man and describe the important clinical, histopathologic, and imaging findings. Computed tomography shows a well-defined hypodense mass with septations. Magnetic resonance imaging shows intermediate T1 and bright T2 signal of the mass and also demonstrates the characteristic marked contrast enhancement.

Increased mortality in hypernatremic burned patients

Introduction: In-hospital hypernatremia develops usually iatrogenically from inadequate or inappropriate fluid prescription. In severely burned patient an extensive initial fluid resuscitation is necessary for burn shock survival. After recovering of cellular integrity the circulating volume has to be normalized. Hereby extensive water and electrolyte shifts can provoke hypernatremia. Purpose: Is a hypernatremic state associated with increased mortality? Method: Retrospective study for the incidence of hypernatremia and survival in 40 patients with a totally burned surface area (TBSA) >10%. Age, sex, TBSA, ABSI-Score and fluid resuscitation within the first 24 hours were analyzed. Patients were separated in two groups without (Group A) or with (Group B) hypernatremia. Results: Hypernatremia occurred on day 5±1.4. No significant difference for age, sex, TBSA, ABSI-Score and fluid resuscitation within the first 24 hours were calculated. In Group A all patients survived, while 3 of the hypernatremic patient in Group B died during ICU-stay (Odds-ratio = 1.25; 95% CI 0.971–1.61; p=0.046). Conclusion: Burned patients with an in-hospital acquired hypernatremia have an increased mortality risk. In case of a hypernatremic state early intervention is obligatory. There is a need of a fluid removal strategy in severely burned patient to avoid water imbalance.

Significant [C3a] Increase in Free Flaps After Prolonged Ischemia

BACKGROUND Free tissue transfer (FTT) represents a clinical model to measure ischemia-reperfusion injury (IRI). This study was conducted to detect substances relevant for IRI after FTT. METHODS Eighteen patients underwent lower leg reconstruction with free myocutaneous latissimus dorsi muscles and were monitored clinically and by microdialysis technique. Patients were retrospectively classified as group A (n = 12) (no prolonged IRI) or group B (n = 6) (prolonged IRI). One catheter was placed into the flap and one into the reference tissue. Samples were collected during ischemia and in 90 min steps after reperfusion. Biochemical substances (glucose, pyruvate, lactate, and glycerol) and immunological substances (interleukin 8 [IL-8], complement 3a [C3a], and regulated on activation normal T cell expressed and secreted [RANTES]) were then analyzed. RESULTS All free myocutaneous latissimus dorsi flaps healed primarily. Minor complications included revisions of the microvascular anastomoses due to hematoma or thrombus formation and increased total flap ischemia time in group B significantly when compared to group A (P < 0.001). No significant differences of biochemical substance concentrations were detected during reperfusion in target and control tissue of both groups. IL-8 and C3a were at detectable levels, whereas the results for RANTES were inconsistent. Either for group A and group B, we found higher concentrations of C3a in target tissue compared with control tissue. Furthermore, during the first 90 min of reperfusion, we found a highly significant increase of C3a (P < 0.001) in the target tissue of patients with increased ischemia time. CONCLUSIONS Given our results, C3a is a highly sensitive early indicator of ischemia-reperfusion damage. Our results give further insight into development of IRI after complicated FTT.

Handinfektionen: Evaluation eines zweizeitigen Therapieregimes

INTRODUCTION Infections of the hand are common diseases in hand surgery departments. The correct diagnosis and subsequent treatment is difficult and is often underestimated. In literature different and often conflicting treatments are recommended. The present study retrospectively analysed our two-stage surgical treatment. PATIENTS AND METHODS 60 patients (mean age: 51 years, 38 male, 22 female) were studied retrospectively on the basis of the diagnosis hand infection (ICD L03.-). In all patients, a rapid and radical surgical debridement without wound closure was performed. An antibiotic therapy was initiated. We investigated how often wound closure during a second-look operation, following a period of open wound treatment with antiseptic dressing was successful possible. Furthermore, the patients were followed up in our outpatient clinic. RESULTS A successful secondary wound closure was possible after on average 38.7 h and in 92% of the patients. 8% of patients required further surgical treatment. These patients presented with either an existing disease or a delayed presentation with initial antibiotic treatment. Antibiotic therapy was performed on an average for 8.7 days. Altogether for 85% of the 58 patients examined in our outpatient clinic the therapy could be terminated after 3 weeks with a full recovery of function of the injured hand and with full force measurements. The inability to work was on average 16 days. DISCUSSION The two-stage surgical treatment, with radical debridement and open wound dressing in our collective is an adequate treatment for infections of the hand. It is a safe procedure, that allows for combination with an antibiotic therapy by which a rapid restoration of function of the injured hand is possible.

Early postoperative alterations of ventilation parameters after tracheostomy in major burn injuries.

Purpose: In patients with major burn injuries mechanical ventilation is often required for longer periods. Tracheostomy (TS) plays an integral role in airway management. We investigated the effect of TS on ventilation parameters within 8 hours after TS. Materials: A retrospective analysis of severely burned patients admitted to the burn unit of a German University Hospital was performed. Ventilation parameters 8 hours before and after TS were registered. Results: A retrospective analysis of 20 patients which received surgical TS was performed. Mean age was 52±19 years. Mean abbreviated burned severity index (ABSI) was 8.3±2.2. A mechanical ventilation was required for 14.3±4.8 days. TS was performed on day 7±4. Inspiratory oxygen concentration (FiO2) (p<0.001), peak inspiratory pressure (p<0.001), positive end-expiratory pressure (p=0.003) and pulmonary resistance (p<0.001) were reduced significantly after TS. The arterial partial pressure of oxygen/FiO2-ratio increased significantly after TS (p<0.001). Conclusions: We demonstrate that TS reduces invasiveness of ventilation in severely burned patients and by this can optimize lung protective ventilation strategy.