Jonas Kolbenschlag

Upper extremity ischemia is superior to lower extremity ischemia for remote ischemic conditioning of antero-lateral thigh cutaneous blood flow.

Remote ischemic conditioning (RIC) is known to improve microcirculation in various settings, but little is known about the impact of the amount of ischemic tissue mass or the limb itself. Since ischemia and subsequent necrosis of flaps is one of the most dreaded complications in reconstructive surgery, adjuvant methods to improve microcirculation are desirable. We therefore performed a randomized trial to compare the effect of arm versus leg ischemia for RIC of the cutaneous microcirculation of the antero–lateral thigh. Forty healthy volunteers were randomized to undergo 5 min of ischemia of either the upper or lower extremity, followed by 10 min of reperfusion.Ischemia was induced by a surgical tourniquet applied to the proximal limb, which was inflated to 250 mmHg for the upper and 300 mgHg for the lower extremity. This cycle was repeated a total of three times. Cutaneous microcirculation was assessed by combined laser doppler spectrophotometry on the antero–lateral aspect of the thigh to measure cutaneous blood flow (BF), relative hemoglobin content (rHb), and oxygen saturation (StO2). Baseline measurements were performed for 10 min, after which the ischemia/reperfusion cycles were begun. Measurements were performed continuously and were afterwards pooled to obtain a mean value per minute. Both groups showed significant increases in all three measured parameters of cutaneous microcirculation after three cycles of ischemia/reperfusion when compared to baseline (BF: 95.1% (P < 0.001) and 27.9% (P = 0.002); rHb: 9.4% (P < 0.001) and 5.9% (P < 0.001), StO2: 8.4% (P = 0.045) and 9.4% (P < 0.001). When comparing both groups, BF was significantly higher in the arm group (P = 0.019 after 11 min., P = 0.009 after 45 min). In conclusions, both ischemic conditioning of the upper and lower extremity is able to improve cutaneous BF on the ALT donor site. However, RIC of the upper extremity seems to be a superior trigger for improvement of cutaneous BF.

Repetitive extracorporeal shock wave applications are superior in inducing angiogenesis after full thickness burn compared to single application

OBJECTIVE Burn wounds remain a challenge due to subsequent wound infection and septicemia, which can be prevented by acceleration of wound healing. The aim of the study was to analyze microcirculation and leukocyte endothelium interaction with particular focus on angiogenesis after full-thickness burn using three different repetitions of low energy shock waves. METHODS Full-thickness burns were inflicted to the ears of hairless mice (n=44; area: 1.6±0.05 mm2 (mean±SEM)). Mice were randomized into four groups: the control group received a burn injury but no shock waves; group A received ESWA (0.03 mJ/mm2) on day one after burn injury; group B received shock waves on day one and day three after burn injury; group C ESWA on day one, three and seven after burn injury. Intravital fluorescent microscopy was used to assess microcirculatory parameters, angiogenesis and leukocyte interaction. Values were obtained before burn (baseline value) immediately after and on days 1, 3, 7 and 12 after burn. RESULTS Shock-wave treated groups showed significantly accelerated angiogenesis compared to the control group. The non-perfused area (NPA) is regarded as a parameter for angiogenesis and showed the following data on day 12 2.7±0.4% (group A, p=0.001), 1.4±0.5% (group B, p<0.001), 1.0±0.3% (group C, p<0.001), 6.1±0.9% (control group). Edema formation is positively correlated with the number of shock wave applications: day 12: group A: 173.2±9.8%, group B: 184.2±6.6%, group C: 201.1±6.9%, p=0.009 vs. control: 162.3±8.7% (all data: mean±SEM). CONCLUSION According to our data shock waves positively impact the wound healing process following burn injury. Angiogenesis showed significantly improved activity after shock wave application. In all three treatment groups angiogenesis was higher compared to the control group. Within the ESWA groups, double applications showed better results than single application and three applications showed better results than single or double applications.

Thoracic Wall Reconstruction after Tumor Resection

Introduction Surgical treatment of malignant thoracic wall tumors represents a formidable challenge. In particular, locally advanced tumors that have already infiltrated critical anatomic structures are associated with a high surgical morbidity and can result in full-thickness defects of the thoracic wall. Plastic surgery can reduce this surgical morbidity by reconstructing the thoracic wall through various tissue transfer techniques. Sufficient soft-tissue reconstruction of the thoracic wall improves quality of life and mitigates functional impairment after extensive resection. The aim of this article is to illustrate the various plastic surgery treatment options in the multimodal therapy of patients with malignant thoracic wall tumors. Materials and methods This article is based on a review of the current literature and the evaluation of a patient database. Results Several plastic surgical treatment options can be implemented in the curative and palliative therapy of patients with malignant solid tumors of the chest wall. Large soft-tissue defects after tumor resection can be covered by local, pedicled, or free flaps. In cases of large full-thickness defects, flaps can be combined with polypropylene mesh to improve chest wall stability and to maintain pulmonary function. The success of modern medicine has resulted in an increasing number of patients with prolonged survival suffering from locally advanced tumors that can be painful, malodorous, or prone to bleeding. Resection of these tumors followed by thoracic wall reconstruction with viable tissue can substantially enhance the quality of life of these patients. Discussion In curative treatment regimens, chest wall reconstruction enables complete resection of locally advanced tumors and subsequent adjuvant radiotherapy. In palliative disease treatment, plastic surgical techniques of thoracic wall reconstruction provide palliation of tumor-associated morbidity and can therefore improve patients’ quality of life.

Remote Ischemic Conditioning improves blood flow and oxygen saturation in pedicled and free surgical flaps.

Background: Surgical flaps have become safe and reliable reconstructive tools, but total flap loss rates as high as 25 percent and partial flap loss rates as high as 36 percent have been reported due to insufficient perfusion. Therefore, a reliable, noninvasive, and effective way to improve the microcirculation of surgical flaps is desirable. The aim of this study was to assess the effect of remote ischemic conditioning on the microcirculation of pedicled and free surgical flaps. Methods: Thirty patients undergoing free (n = 20) and pedicled (n = 10) tissue transfer were included in this study. Remote ischemic conditioning was applied on the upper extremity for three cycles on postoperative days 1, 5, and 12. Blood flow, tissue oxygen saturation, and relative hemoglobin content were measured by means of a combination of laser Doppler and spectroscopy (O2C device) in the flap and the surrounding tissue. The relative increase compared with baseline measurements was assessed. Results: Blood flow increased significantly in controls on all 3 postoperative days (p < 0.05 for all). In free flaps, tissue oxygen saturation improved significantly on postoperative days 1 and 12 and blood flow improved significantly on postoperative days 5 and 12 (p < 0.05). In pedicled flaps, blood flow and tissue oxygen saturation increased on postoperative day12, but not significantly. Conclusions: Remote ischemic conditioning is a safe, inexpensive, fast, and reliable method to improve the microcirculation of surgical flaps. Further research is warranted to see whether such an improvement translates into improved flap survival, but it is likely. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Surgical correction of pterygium colli

BACKGROUND/PURPOSE Webbing of the neck is a deformity seen in various syndromes, including Turners, Klippel-Feil, or Escobar-Syndrome. There is little information in literature to provide the surgeon with treatment options for these children. We reviewed our experience with the surgical correction of pterygium colli deformity in eleven patients. METHODS A retrospective review was conducted on all patients that underwent surgical correction of pterygium colli deformity within the last 8 years. Data recorded included patient demographics, diagnostic evaluation, surgical treatment, complications, and outcome. RESULTS Eleven patients underwent an operation to correct pterygium colli deformity. Six patients had z-plasties, and three patients underwent bilateral excision of an ellipsoid portion of skin and closure via unilateral advancement flaps. We later modified our technique to combine the unilateral advancement flap with Z-Plasties. The mean age at operation was 10.7 years (range 2-23 years). No postoperative wound infections occurred. Mild recurrence of webbing was found in one case. In four patients we found mild to moderate hypertrophic scarring. Average overall content was 7.8 (scale of 0-10, 10 being total content), and all patients, respectively their parents, would undergo the surgery again. Mean length of follow-up was 28.3 months. CONCLUSION Our study shows that overall patient satisfaction is very high, but an accurate preoperative planning with the patient and parents and an honest discussion of all questions and concerns raised by the parents are essential.

Advanced Microcirculatory Parameters of Lower Extremity Free Flaps during Dangling and Their Influencing Factors.

BACKGROUND Dangling of the leg to habituate a free flap to the lower extremity is common practice. However, little is known about the microcirculatory changes in free flaps and the influence of comorbidities. METHODS Tissue oxygen saturation (StO2) and hemoglobin content (tissue hemoglobin index [THI]) of 39 lower extremity free flaps was measured during dangling on postoperative days (PODs) 6 to 9. We assessed the maximal desaturation during dangling and re-elevation and the maximal increase in THI as well as the time required to reach a stable plateau during dangling, among others. RESULTS All parameters showed significant changes during dangling (desaturation during dangling: 0.23 ± 10.7 vs. - 4.66 ± 12.6%, p = 0.001 for POD 6 vs. 7; further desaturation after re-elevation: - 11.1 ± 7.4 versus - 14.5 ± 7.8%, p = 0.001 for POD 6 vs. 9; THI increase during dangling: from 3.4 ± 1.6 to 4.2 ± 1.8 AU, p = 0.008, time to THI plateau: 1.7 ± 1.2 vs. 2.5 ± 1.7 minutes, p = 0.004 for POD 6 vs. 7). Age, gender, and smoking did not influence the mentioned parameters. Nondiabetic patients showed a significant increase of baseline StO2, whereas diabetic patients did not (p = 0.009 vs. 0.11). For THI, both diabetic and hypertensive patients showed a lower increase in THI on the first day of dangling (p = 0.056; p = 0.009) and significantly lower baseline values on the last day (0.046 for both). CONCLUSION Duration of dependency seems to have the greatest impact on microcirculation during dangling, although comorbidities may interfere with the adaptive processes. An earlier start of dangling could safely be applied in most patients. Special care needs to be taken in diabetic and hypertensive patients.

New model for long-term investigations of cutaneous microcirculatory and inflammatory changes following irradiation

Radiotherapy is used for curative and palliative treatment. However, its negative effect on normal tissue is a limiting factor for the deliverable dose. Microcirculatory breakdown and prolonged inflammation in particular are major features of late side effects. The purpose of this study was to develop a reliable animal model that will allow a long-term in vivo analysis of microcirculation and inflammation following irradiation. A single dose of 90 Gy was delivered to the ears of hairless mice (n = 15). Intravital fluorescent microscopy was used to assess microcirculatory parameters and leukocyte behaviour. Values for the identical (control) areas were obtained before as well as during the following days, weeks and months following irradiation. The arteriolar and venular diameter increased up to Day 14, decreased during the following months, and increased again after one year. The red blood cell velocity increased up to 145% on Day 3, decreased on Day 7 to 115%, and stayed above baseline value the whole year. The integrity loss of the endothelium increased up to Day 7 and continued up to Day 75 after radiation. After one year, the oedema was at the baseline level. Leukocytes showed their maximal activity at one year after trauma. An increase was measured up to Day 25; the lowest values were measured at Day 40 post-irradiation, followed by a repeated increase. The present model allows a certain visualization of microcirculatory disturbances and inflammation over a period of months. This permits the possibility of long-term investigations of the underlying pathophysiology following irradiation, including possible drug interactions.

Changes of oxygenation and hemoglobin-concentration in lower extremity free flaps during dangling.

Lower extremity reconstruction utilizing free tissue transfer has become a common and safe procedure. Postoperative care and especially timing and duration of dangling however have not yet been extensively studied. We therefore aimed to assess the changes in oxygenation and hemoglobin concentration in lower extremity free flaps during dangling. A total of 19 patients who underwent microsurgical reconstruction of the lower leg (nine parascapular, five latissimus dorsi, and five anterolateral thigh [ALT] flaps) were included in a prospective study. Beginning on the 6th postoperative day (POD), dangling was commenced three times a day for 5 minutes each and gradually increased over time. Oxygenation and concentration of hemoglobin was measured using noninvasive near infrared spectroscopy. A specific pattern of oxygenation and hemoglobin concentration was identified. After beginning of dangling, oxygenation and hemoglobin concentration rises, followed by a rapid decrease. Over the course of training, the predangling saturation values increased steadily, resulting in a 9.5% increase on POD 9. The time needed for the flap to regain its predangling oxygenation level declined over the course of training from 5.1 minutes on POD 6 to 3.8 minutes on POD 9. The ALT flaps showed the highest increase in predangling saturation values (12%) and the most pronounced decrease in recovery time (6.7 minutes on POD 6 vs. 3.5 minutes on POD 9). The type of flap seems to influence behavior during dangling. However, further influencing factors need to be identified to enable reconstructive surgeons to tailor not only the flap but also the aftercare to the individual patient.

Mikrochirurgische Ausbildung in Deutschland – Ergebnisse einer Umfrage unter Weiterbildungsassistenten und Weiterbildern

Reconstructive microsurgery is an essential part of plastic surgery. To live up to the high technical demands of todays sophisticated techniques, a structured microsurgical training is required. However, such curricula are rare in Germany. We therefore evaluated the concepts and requests of trainers as well as trainees regarding an optimal microsurgical training. We found that the demands of both sides to be fairly similar. How-ever, there were factors potentially hindering the implementation of such curricula, foremost the increasing economic pressure. Based on our findings, representatives of microsurgical trainers and trainees, together with national societies might be able to establish a national curriculum for microsurgical training. The clinical implementation of such a structured train-ing will require significant personal resources. However, this expenditure seems to be justified by the increasing complexity of techniques, the rising demand of patients and the limited time for -surgical training.

Influence of ISDN, l-NAME and selenium on microcirculation, leukocyte endothelium interaction and angiogenesis after frostbite

BACKGROUND The body of knowledge regarding the different facets of frostbite injury continues to expand. However, beside the administration of physiological saline, local rewarming, local disinfection and symptomatic medications, today no causal therapy is known which would accelerate angiogenesis and wound healing. The aim of this study was to investigate the influences of dilative acting drugs on microcirculation, angiogenesis and leukocyte behavior. MATERIALS AND METHODS Ears of male hairless mice (n=40) were inflicted with full thickness frostbites using a cold air jet. Then the affects of four intraperitoneal injections of isosorbitdinitrate (ISDN, n=10), l-nitroarginine-methyl-ester (l-NAME, n=10), selenium (n=10) or sodium chloride (n=10; each administered to one of four corresponding study groups), on microcirculation, leukocyte-endothelial interaction and angiogenesis were investigated over a 12-day period using intravital fluorescent microscopy. RESULTS Angiogenesis was most improved by ISDN (36.8 vs. 54.5% non-perfused area on day 3, 3.9 vs. 17.0% on day 7 compared to selenium, p<0.006). Venular diameter was most significantly dilated in the ISDN-group, l-NAME showed significantly decreased diameter over the complete time of 12 days. ISDN had positive influences on edema formation, which was significantly reduced compared to control (27% lower values compared to control; p=0.007 on day 3). The l-NAME-group showed the significant highest leukocyte-adhesion compared to control on days 7 and 12 (53% resp. 58% higher, p<0.006). CONCLUSION Overall, out of all the drugs tested, ISDN improved angiogenesis, dilated venules and decreased edema formation and therefore seems to have the greatest positive impact on these crucial parameters after frostbite injury.