[Robot-assisted Microsurgery in Lower Extremity Reconstruction]. / Roboter-assistierte Mikrochirurgie in der Rekonstruktion der unteren Extremität.

BACKGROUND: In recent years, various robotic systems specifically designed for microsurgical tasks have been developed and approved. There is not much evidence for these systems to date. In our study, we examined the use of robot-assisted microsurgery in the reconstruction of the lower extremity. PATIENTS/MATERIAL AND METHODS: Data was prospectively collected between February and November 2023. The Symani robotic system was used in 42 robot-assisted microsurgical procedures on the lower extremity, and the results were evaluated and documented. RESULTS: The average age of the patients was 57±18 years. A total of 39 free flap reconstructions (95%), one lymphatic surgical procedure (3%) and two nerve transfers (5%) were performed. In total, 46 anastomoses and coaptations were carried out. This included six arterial end-to-end anastomoses (11%), seven arterial end-to-side anastomoses (13%), 36 venous end-to-end anastomoses (65%), two lymphovenous anastomoses (4%), and five epineural coaptations in the context of nerve transfers (9%). Arterial end-to-end anastomoses took an average of 26±12 minutes, and arterial end-to-side anastomoses took 42±21 minutes. The venous anastomoses took an average of 33±12 minutes. Epineural coaptations took an average of 24±13 minutes. In no procedure was there a need for a conversion to conventional hand suturing. There were two arterial thromboses (5%), one of which was successfully revised to save the flap. One total flap loss occurred, but there were no partial flap losses. CONCLUSION: Using the Symani robotic system for microsurgical reconstruction of the lower extremity, we were able to demonstrate results that are comparable to conventional microsurgery.

Scalp Reconstruction Using the Latissimus Dorsi Free Flap: A 12-Year Experience.

BACKGROUND: Complex scalp defects are regularly reconstructed using microvascular tissue transfer. The latissimus dorsi free flap is one of the workhorse flaps used in scalp reconstruction. These cases necessitate, particularly in the elderly, a close cooperation between plastic surgeons and neurosurgeons. The purpose of this study was to evaluate the suitability of the latissimus dorsi free flap for complex scalp reconstructions and to analyze potential risk factors. METHODS: A retrospective study identified 43 patients undergoing complex scalp reconstruction using a latissimus dorsi free flap at our department between 2010 and 2022. RESULTS: The mean patient age was 61 ± 18 years. Defects were mostly caused by oncologic tumor resections (n = 23; 55%), exposure to a cranioplasty (n = 10; 23%) or infection (n = 4; 9%). The most frequent recipient vessels were the superficial temporal artery (n = 28; 65%), external carotid artery (n = 12; 28%) and the venae comitantes (n = 28; 65%), external jugular vein (n = 6; 14%). The reconstructive success rate was 97.7%. There was one total flap loss (2%). Partial flap loss occurred in five cases (12%). Follow-up was 8 ± 12 months. Major complications were seen in 13 cases, resulting in a revision rate of 26%. Multivariate logistic regression identified active tobacco use as the only risk factor for major complications (odds ratio 8.9; p = 0.04). CONCLUSION: Reconstruction of complex scalp defects using the latissimus dorsi free flap yielded high success rates. Among the potential risk factors, active tobacco use seems to affect the outcome of complex scalp reconstructions.

Low-energy extracorporeal shockwave therapy (ESWT) improves metaphyseal fracture healing in an osteoporotic rat model.

PURPOSE: As result of the current demographic changes, osteoporosis and osteoporotic fractures are becoming an increasing social and economic burden. In this experimental study, extracorporeal shock wave therapy (ESWT), was evaluated as a treatment option for the improvement of osteoporotic fracture healing. METHODS: A well-established fracture model in the metaphyseal tibia in the osteoporotic rat was used. 132 animals were divided into 11 groups, with 12 animals each, consisting of one sham-operated group and 10 ovariectomized (osteoporotic) groups, of which 9 received ESWT treatment. Different energy flux intensities (0.15 mJ/mm2, 0.35 mJ/mm2, or 0.55 mJ/mm2) as well as different numbers of ESWT applications (once, three times, or five times throughout the 35-day healing period) were applied to the osteoporotic fractures. Fracture healing was investigated quantitatively and qualitatively using micro-CT imaging, quantitative real-time polymerase chain reaction (qRT-PCR) analysis, histomorphometric analysis and biomechanical analysis. RESULTS: The results of this study show a qualitative and quantitative improvement in the osteoporotic fracture healing under low-energy (energy flux intensity: 0,15 mJ/mm2) ESWT and with fewer treatment applications per healing period. CONCLUSION: In conclusion, low-energy ESWT seems to exhibit a beneficial effect on the healing of osteoporotic fractures, leading to improved biomechanical properties, enhanced callus-quantity and -quality, and an increase in the expression of bone specific transcription factors. The results suggest that low-energy ESWT, as main treatment or as adjunctive treatment in addition to a surgical intervention, may prove to be an effective, simple to use, and cost-efficient option for the qualitative and quantitative improvement of osteoporotic fracture healing.

Enzymatic debridement for the treatment of severely burned upper extremities - early single center experiences.

BACKGROUND: Severe burns of hands and arms are complex and challenging injuries. The Standard of care (SOC) - necrosectomy with skin grafting - is often associated with poor functional or aesthetic outcome. Enzymatic debridement (ED) is considered one promising alternative but, until recently, results proved to be highly variable. METHODS: Between 04/2014 and 04/2015, 16 patients with deep partial- to full-thickness burns of the upper extremities underwent enzymatic debridement (ED) in our Burn Center and were evaluated for extent of additional surgery, wound healing, pain management and functional parameters. RESULTS: Following ED, no further surgical intervention was required in 53.8 % of the study population. In patients who required surgical treatment, the the skin-grafted area could be reduced by 37.0 % when compared to initial assessment. Time from injury to ED was 24.4 h and patients were able to start physical therapy after 2.0 days but suffered from prolonged wound closure (28.0 days). Regionally administered anesthesia proved to be superior to pain medication alone as pain levels and consumed morphine-equivalent were lower. Post-demission follow-up showed good functional results and pain levels with low scores in two self-report questionnaires (DASH, PRWE-G) but 3 patients reported increased susceptibility to shear stress. Based on these early experiences, we developed a 3-step algorithm for consecutive patients allowing appropriate and individualized treatment selection. CONCLUSIONS: We see a potential benefit for ED in the treatment of severely burned hands and forearms but further investigations and proper prospective, randomized controlled trials are needed to statistically support any outlined assumptions.

Influence of Cdp-Choline Administration on Early Burn Edema in Rats.

PURPOSE: The cholinergic anti-inflammatory pathway may play an important role in early burn edema. Therefore, we evaluated the influence of cdp-choline on early systemic burn edema and leukocyte activation in shock in rat mesenteries after burn plasma transfer. METHODS: Burn plasma harvested from donor rats 4 hours after thermal injury (30% total body surface area, 100°C water, 12 seconds) was administered intravenously to healthy animals during 2 hours of intravital microscopy. Shamburn plasma (same procedure but water at 37°C) was transferred for negative controls. In the study group, bolus injection of 100 mg/kg body weight cdp-choline was undertaken 15 minutes before examination. Intravital microscopy was performed in the ileal portion of rat mesenteries at 0, 60, and 120 minutes. Capillary leakage was assessed by fluorescein isothiocyanate-albumin extravasation and leukocyte-endothelial interaction were observed via transillumination microscopy. To assure comparable hemodynamic conditions, microhemodynamic parameters, foremost venular wall shear rate, were assessed. RESULTS: Capillary leakage increased significantly after burn plasma transfer when compared to the shamburn group. Additional intravenous administration of cdp-choline attenuates macromolecular efflux to shamburn levels. Leukocyte activation is reduced after cdp-choline treatment. CONCLUSIONS: The significant increase of albumin efflux in rat mesenteries after burn plasma transfer is decreased by additional cdp-choline bolus administration. Further investigations for proof of the relevance of the cholinergic anti-inflammatory pathway in early burn trauma are strongly required.

Microcirculatory effects of physostigmine on experimental burn edema.

In order to further understand the role of the cholinergic anti-inflammatory pathway, the authors determined the effects of burn plasma from donor rats (DRs) on the microvascular circulation of healthy recipient rats and whether these could be altered by pretreatment with physostigmine (PT). DRs underwent thermal injury (100°C water, 12 seconds, 30% BSA) for positive controls. For negative controls DRs underwent sham burn (same procedure but water at 37°C). DR-plasma (harvested 4 hours posttrauma) was transferred to healthy rats. Bolus injection of PT (70 µg/kg body weight) was performed 15 minutes before starting the infusion of DR-plasma in the study group. Intravital microscopy was performed in mesenteric venules (0/60/120 minutes). Edema was assessed by fluorescein isothiocyanate (FITC)-albumin extravasation. Additionally, leukocyte rolling and sticking (cells/mm) as well as hemodynamic parameters were assessed. Burn plasma transfer significantly increases albumin extravasation in healthy individuals when compared with sham-burn treatment. Additional bolus administration of PT (70 µg/kg body weight) to burn plasma treatment reduces plasma extravasation to sham-burn levels. PT also attenuates leukocyte-endothelial interactions. After 120 minutes no significant changes in the systemic circulation (mean arterial pressure, heart rate, wall shear rate) were found between the groups. Burn plasma transfer results in significant increases in plasma extravasation and leukocyte-endothelial wall adherence, which are reversed by pretreatment with PT. These results suggest that the cholinergic anti-inflammatory pathway may play a role in the microcirculatory response to thermal injury.

Intravital pathophysiological comparison of acid- and alkali-burn injuries in a murine model.

BACKGROUND: The breakdown of skin microcirculation plays a key role in the pathophysiology of chemical burns. Available data for alkali and acid injuries are rare. To determine the pathophysiological similarities and differences, two comparable in vivo acid and alkali burn models were developed. MATERIALS AND METHODS: Deep partial-thickness acid burns (32% hydrochloric acid) or alkali burns (11% sodium hydroxide solution) were inflicted to the ears of hairless mice (n = 17). Intravital fluorescent microscopy was used to assess microcirculation, angiogenesis, and leukocyte-endothelium interaction over a 21-d period. RESULTS: The angiogenesis occurred significantly faster after acid burns than after alkali burns in the first 3 days (nonperfused area day 3, 80% ± 9% [acid] versus 94% ± 17% [alkali]; P = 0.045) and then a significant acceleration occurs in the alkali group: nonperfused area day 14, 27% (alkali) versus 57% (acid), P = 0.004. The loss of functional vessel density was more pronounced after acid burns (directly after trauma, 87% [alkali] versus 79% [acid], P = 0.049). The other parameters such as rolling and sticking leukocytes, edema formation, and arteriolar and venular red blood cell velocities and diameters showed similar results. CONCLUSIONS: The comparison of analogous intravital acid and alkali burns shows that despite many similarities in the microcirculatory parameters, there was a marked difference particularly in the course of the tissue regeneration by angiogenesis. The longer lasting destruction by alkali burns stands in contrast to the later onset but faster regeneration by angiogenesis compared with that by acid burns.

Intravital pathophysiologic comparison of frostbite and burn injury in a murine model.

BACKGROUND: The breakdown of skin microcirculation and the leukocyte-endothelium interaction are assumed to play key roles in the pathophysiology of burn and frostbite injuries. Available data on frostbite and burn injuries were collected using different experimental models and setups, which limits direct comparisons of these thermal traumata significantly. To determine pathophysiologic similarities and differences, two comparable in vivo frostbite and burn models were used to assess microcirculatory and angiogenetic changes in burn and frostbite injuries. MATERIALS AND METHODS: Either deep partial thickness no-touch burns or frostbite injuries were inflicted to the ears of hairless mice (n = 40) by a hot or cold gas jet (117.0 ± 2.1°C for 1 s and -195.8 ± 2.7°C for 1.5 s, respectively) resulting in a necrotic, nonperfused area of about 1.56 ± 0.28 mm2. Intravital fluorescent microscopy was used in combination with fluorescent dyes in order to assess the microcirculation, angiogenesis, and leukocyte-activity over a 12-d period. RESULTS: The angiogenesis occurred significantly faster after frostbite than after burn (16.4% ± 4.5% versus 30.6% ± 2.8% nonperfused area, compared with the baseline value on d 7 (P = 0.009)). The loss of functional vessel density was significantly more pronounced after frostbite (57.6% ± 2.2% versus 89.2% ± 4.9% (P < 0.001)). However, the area recovered faster. The edema formation, as a parameter for endothelial integrity, was significantly more pronounced and lasted longer after frostbite, compared with the burn injury, and reached its maximum level on d 7 after trauma (162.4% ± 4.2% versus 142.% ± 5.9%; P = 0.007). In contrast to the rolling leukocytes, which showed the same increase on d 1 and then a subsequent decrease in both groups, the number of adherent leukocytes after the burn was markedly higher on d 1 (480% versus 167%; P = 0.001) but decreased much faster. The number of adherent leukocytes after frostbite remained significantly higher than those of the burn group during the entire observation. CONCLUSION: The comparison of analogous intravital burn and frostbite models indicates that despite the similarities, decisive microcirculatory differences in extension and recovery from these two types of thermal trauma exist.

Burn model for in vivo investigations of microcirculatory changes.

OBJECTIVE: The treatment of burns remains a challenge due to the associated high morbidity and mortality. Besides the administration of physiologic saline, local disinfection, and symptomatic medications, no causal therapy is known to reduce the tissue damage and accelerate wound healing. The aim of the study was to develop a reliable burn model that allows for reproducible quantitative in vivo analysis of the microcirculation, angiogenesis, and leukocyte endothelium interaction after burn injury. METHODS: Experiments were carried out on male hairless mice (n = 9). Full-thickness burns were inflicted with a hot air jet without any contact to the tissue (117 +/- 2.1 degrees C for 1 second; burn area: 1.3 mm(2)). Intravital fluorescent microscopy, in combination with FITC-dextran as plasma marker, was used to assess microcirculatory standard parameters; leukocytes were stained with rhodamine 6G. Values were obtained before, immediately after, as well as at days 1, 3, 7, and 14 postburn. RESULTS: The nonperfused area decreased during the observed period and perfusion was almost completely due to angiogenesis at day 14. No posttraumatic expansion of the nonperfused area after 24 hours could be observed. Leukocyte endothelium interaction showed its maximum 24 hours postburn. The formation of edema occurred immediately postburn and decreased during the following observation time. CONCLUSION: The developed burn model allows a reproducible assessment with significant results of the microcirculation, angiogenesis, and leukocyte endothelium interaction without causing mechanical damage to the tissue; therefore, this model qualifies for the further investigations of interventional drugs to decrease the effects of burn injury.