Comparison of Extracorporal Shock Wave Pretreatment to Classic Surgical Delay in a Random Pattern Skin Flap Model:

An Innovative and Economical Device for Ischemic Preconditioning of the Forehead Flap Prior to Pedicle Division: A Comparative Study

BACKGROUND

 Ischemic preconditioning of the forehead flap prior to pedicle division helps to improve angiogenesis. Clamping the pedicle by a clamped rubber band with vessel forceps is often clinically applied. However, the severe pain and unstable blocking effect influenced the preconditioning process. In this study, we described an innovative device designed for ischemic preconditioning and compared its efficacy with the clamped rubber band.

METHODS

 The device consists of a self-locking nylon cable tie with a buckle and a rubber tube. The rubber tube is fed over the cable tie to act as a soft outer lining and the cable tie is tightened across the pedicle to block the perfusion for ischemic preconditioning. This device and the standard clamped rubber band were applied respectively before division surgery. The constriction effect, reliability, reproducibility, and the patients' pain tolerance were compared.

RESULTS

 A total of 20 forehead flaps were included. The cable tie had less incidence of loosening (7.7% vs. 16.6%, p < 0.05) and maintained the pressure more effectively. The pain score for the nylon cable tie was significantly lower than the clamped rubber band (4.25 ± 1.02 vs. 6.75 ± 1.12, p < 0.05), especially for 10 pediatric patients (4.50 ± 0.85 vs. 8.10 ± 1.20, p < 0.01). All 20 pedicles were successfully divided at 19 to 22 days with no surgical complications.

CONCLUSION

 Compared with the clamped rubber band, the cable tie produces a more reliable and reproducible ischemic preconditioning effect. It is also better tolerated by the patients. Therefore, we recommend using the nylon cable tie as the preferred device for ischemic preconditioning of the forehead flap.

An animal experiment study on the application of indocyanine green angiography in the harvest of multi-angiosome perforator flap

Background

This study sought to explore the application value of indocyanine green angiography (ICGA) in the harvest of multi-angiosome perforator flap and the effect of low molecular weight heparin (LMWH) on the survival of postoperative flap.

Methods

Twenty-four SD male rats were selected to construct a three-angiosome perforator flap model with the unilateral iliolumbar artery perforator. They were randomly divided into two groups: the control group was injected with indocyanine green (ICG) into the femoral vein during the operation, and the fluorescence signal was collected and quantitatively analyzed using Real-Time Image Guided System to determine the intraoperative fluorescence imaging length. The experimental group was injected subcutaneously with LMWH (400 U/kg) after 0.5 h postoperatively, and the control group was injected with the same amount of normal saline. The injection was repeated at the same time each day from 0 to 7 days postoperatively. After the flap was sutured in situ, ICGA was performed at 0, 1, 3, 5, and 7 days postoperatively to observe the vascular structure of the two groups of flaps. The flap survival length of the control group was counted at 7 days postoperatively, and the correlation between the intraoperative fluorescence imaging length and the survival length at 7 days postoperatively was calculated. The proportion of distal necrosis of the flaps between the two groups was compared at 7 days postoperatively.

Results

The average length of intraoperative fluorescence imaging in the control group was 6.29±0.50 cm, and the survival length of the flap at 7 days postoperatively was 8.24±0.52 cm. The actual survival length was higher than the intraoperative fluorescence imaging length, with a ratio of 1.31±0.08. The difference was statistically significant (P<0.05). At 7 days postoperatively, the flap necrosis ratio of experimental group and control group were 10.92%±1.30% and 19.11%±1.19%, and the flap necrosis ratio of experimental group was lower than that of control group (P<0.001).

Conclusions

ICGA can locate the position of perforator, and can be used to predict and observe the length of distal survival of multi-angiosome perforator flap postoperatively. LMWH can promote the distal survival of flap and reduce flap necrosis.

[The use of reamberin in antishock therapy in severely burned patients]

A 51-year-old severely burned woman had hospitalized at the Clinic of Thermal Injuries of the S.M. Kirov Military Medical Academy with a diagnosis: flame burn in a surface area of 40% (11%)/II-III b degrees of head, neck, trunk, limbs. Inhalation injury of moderate severity. The infusion drug of the combined action reamberin, which has a volemic and antihypoxic effect, had added to the complex antishock therapy. The presented clinical observation demonstrates the favorable course of burn shock: stopping of burn shock 28 hours after injury.

Extracorporal Shock Wave Therapy Enhances Receptor for Advanced Glycated End-Product-Dependent Flap Survival and Angiogenesis

BACKGROUND/OBJECTIVES

Loss of skin flaps due to deteriorated wound healing is a crucial clinical issue. Extracorporal shock wave therapy (ESWT) promotes flap healing by inducing angiogenesis and suppressing inflammation. The receptor for advanced glycation end-products (RAGEs) was identified to play a pivotal role in wound healing. However, to date, the role of RAGE in skin flaps and its interference with ESWT are unknown.

METHODS

Caudally pedicled musculocutanous skin flaps in RAGE and wt mice were treated with low-dose extracorporal shock waves (s-RAGE, s-wt) and analyzed for flap survival, histomorphologic studies, and immunohistochemistry during a 10-day period. Animals without ESWT served in each genotype as a control group (c-RAGE, c-wt). Statistical analysis was carried out by repeated-measures analysis of variance.

RESULTS

Flap necrosis was significantly reduced after ESWT in wt animals but increased in RAGE-deficient animals. Morphometric differences between the 4 groups were identified and showed a delayed wound healing with dysregulated inflammatory cells and deteriorated angiogenesis in RAGE animals. Furthermore, spatial and temporal differences were observed.

CONCLUSIONS

The RAGE controls inflammation and angiogenesis in flap healing. The protective effects of ESWT are dependent on intact RAGE signaling, which enables temporary targeted infiltration of immune cells and neoangiogenesis.

Comparison of incisional delay patterns on a rat random flap model

One of the simplest form of surgical delay can be performed by placing an incision around the flap without undermining, prior to flap elevation. In this study, we have compared the efficiency of different patterns of skin incision to improve flap survival. Twenty-eight animals were used in four groups. Incisional delay was performed prior to flap elevation in the three experiment groups. Complete incision of the three flap edges was performed in the all experiment groups with the exception of an intact skin section on the middle 1/3rd of the bilateral edges in group 1 (bilateral skin edge preserved delay: BSEPD), of a unilateral edge in group 2 (unilateral skin edge preserved delay: USEPD) and of the superior edge in group 3 (superior skin edge preserved delay: SSEPD) without any undermining. Two weeks following the delay procedure, dorsal skin flaps were raised and reinserted back to their place. The results were evaluated with the measurement of necrotic flap area, microangiographic imaging and histological evaluation. The mean percentage of necrotic flap area to whole flap area was 16.94%, 7.54%, 23.34% and 50.6% in the BSEPD, USEPD, SSEPD and control groups, respectively. In selected microangiographic images, vessels were more prominent in the delay groups. The results of the study indicate that three sided incision with an intact skin on the superior edge is not effective in providing a sufficient delay and flap survival improvement when compared to incisions with intact skin on the unilateral and bilateral edges.

Comparison of subdermal and perforator delay techniques on a rat flap model

Background

In this study, we investigated the subdermal and perforator delay phenomena as a method to improve flap survival.

Materials and Methods

In this experimental study, we used 24 rats in three groups. In the control group, the dorsal flaps were elevated and reinserted back to their place. In the experimental groups, we practiced the delay phenomena with two different techniques. In the first experimental group, cranial and lateral side incisions were performed; however, the flaps were not cut-off from the underlying fascia. In the second experimental group, we placed a silicon sheet under the planned flap to cut-off the circulation from the perforator vessels. Four weeks after the delay procedure, the flaps were raised completely and reinserted back to their place.

Results

The average of necrotic area in the control group was 21.9% (±7.70). There was no necrosis in both experimental groups (P < 0.0001). Histological examination revealed that collagen density in both of the experimental groups was increased in comparison to the control group, it has only been found a significant first experimental group (P = 0.0315). We have not found any significant difference in lymphocyte density between the groups. Angiographic imaging has showed an increase in the vascular density in the flaps of the first experimental group.

Conclusion

We believe that both of these delay techniques can be adapted to clinical applications and used safely to increase flap survival.

Blood Congestion Can Be Rescued by Hemodilution in a Random-Pattern Skin Flap

BACKGROUND

There is no standard method to ensure survival of random-pattern skin flaps. The authors developed a rat anemia model to observe survival of random-pattern skin flaps after blood transfusion and hemodilution.

METHODS

Anemia was induced by withdrawal of 35 percent blood volume followed by compensation with the same amount of blood (blood transfusion model) or plasma equivalent (normovolemic hemodilution). Control rats were subjected to a sham procedure. Subsequently, a random-pattern skin flap (1.5 × 6 cm) was elevated on the back of each rat. Physiologic assessments of flap vascularity/viability were performed using laser Doppler spectrophotometry before and after flap elevation.

RESULTS

The normovolemic hemodilution group showed anemia (hemoglobin, 9.5 ± 0.8 g/dl) but less flow occlusion and greater flap survival (72.8 ± 8.6 percent) compared with control (57.4 ± 9.6 percent; p < 0.01) and blood transfusion (62.1 ± 6.5 percent; p < 0.089) groups. In control and blood transfusion groups but not the normovolemic hemodilution group, blood flow was decreased and relative quantity of hemoglobin was increased toward the flap tip, indicating congestion. In control and blood transfusion groups, blood flow and tissue oxygen saturation dropped after flap elevation, but recovered by day 7; congestion gradually improved by day 7.

CONCLUSIONS

The authors determined that congestion promoted necrosis and hemodilution reduced microcirculatory occlusion and increased blood flow and oxygenation in skin flaps. It was suggested that perioperative hemodilution is superior to blood transfusion in any flap operations unless there is a critical systemic need for blood transfusion.

Silk Ligation Delay for the Random Pattern Flap

OBJECTIVE

The purpose of this study is to explore a silk ligation delay for the expanded and unexpanded random flaps to improve the vascularization and survival length of the flap.

METHODS

Marked incision points 2 to 3 cm at every interval along the design line with methylene blue, each incision was about 3 mm long. A subepidermal tunnel was formed on the superfacial layer of dermis between every adjacent incision; another gap was done on the surface of the expander. One end of a No 7 silk thread was inserted into the incision and traversed the surface of the expander until the adjacent incision point, then returned back to the original site through subepidermal tunnel. The both ends of the thread were ligated together to a single knot. All the designed points were performed as above. Then, the ligation procedure was performed along the long axis of the flap from proximal to distal. Both ends of each silk thread were tightly ligated together to a square knot to clamp the soft tissues including the vessels entering the flap. The progress of ligation should depend on blood supply changes of the flap. Remainders would finish under local anesthesia with 0.5% lidocaine or surface anesthetic cream in dressing room at 5 to 7 days after operation as schedule. After that the authors tested the blood supply of the flap and decided the opportunity of final transfer.

RESULTS

There were no complications such as infection, wound dehiscence, expander exposure, significant effusion, and necrosis of the flap in all patients. All the flaps survived completely. Only 1 expander rupture happened during delay operation.

CONCLUSIONS

The technique is a safe and reliable method, it is simple and easy for application, it may provide another choice for the surgical delay.

Effect of botulinum toxin A and nitroglycerin on random skin flap survival in rats

BACKGROUND

A suitable pharmacological substitute for the well-established surgical delay technique for random skin flaps to increase viability has been elusive.

OBJECTIVE

To evaluate the effects of nitroglycerin and botulinum toxin type A on random flap survival in a rat model.

METHODS

The present controlled experimental study was performed in the four groups of rats. One week after intervention in each group, the flap was raised and kept in situ, and flap necrosis was evaluated through follow-up. Group 1 received intradermal botulinum toxin type A (BTX-A) and topical nitroglycerin 2%; group 2 received BTX-A and topical Vaseline (Unilever, USA); group 3 received topical nitroglycerin and intradermal normal saline; and group 4 received topical Vaseline and intradermal normal saline.

RESULTS

BTX-A reduced the area of necrosis compared with control (24% versus 56% respectively; P<0.001). Nitroglycerin application was associated with a trend toward improved flap viability (42% versus 56%; P=0.059). The combination of topical nitroglycerin and BTX-A, compared with Vaseline and BTX-A, was associated with decreased flap necrosis (16.1% versus 24%, respectively), although it was not statistically significant (P=0.45).

CONCLUSIONS

BTX-A was effective in reducing distal flap necrosis. The effect of BTX-A was significantly more pronounced than nitroglycerin ointment.

Effect of botulinum toxin a and nitroglycerin on random skin flap survival in rats

Background

A suitable pharmacological substitute for the well-established surgical delay technique for random skin flaps to increase viability has been elusive.

Objective

To evaluate the effects of nitroglycerin and botulinum toxin type A on random flap survival in a rat model.

Methods

The present controlled experimental study was performed in the four groups of rats. One week after intervention in each group, the flap was raised and kept in situ, and flap necrosis was evaluated through follow-up. Group 1 received intradermal botulinum toxin type A (BTX-A) and topical nitroglycerin 2%; group 2 received BTX-A and topical Vaseline (Unilever, USA); group 3 received topical nitroglycerin and intradermal normal saline; and group 4 received topical Vaseline and intradermal normal saline.

Results

BTX-A reduced the area of necrosis compared with control (24% versus 56% respectively; P<0.001). Nitroglycerin application was associated with a trend toward improved flap viability (42% versus 56%; P=0.059). The combination of topical nitroglycerin and BTX-A, compared with Vaseline and BTX-A, was associated with decreased flap necrosis (16.1% versus 24%, respectively), although it was not statistically significant (P=0.45).

Conclusions

BTX-A was effective in reducing distal flap necrosis. The effect of BTX-A was significantly more pronounced than nitroglycerin ointment.

Value of remote ischaemic preconditioning in rat dorsal skin flaps and clamping time

OBJECTIVE

According to previous reports, remote ischaemic preconditioning (RIPC) is a "delay" procedure that is highly likely to be useful for preventing skin flap necrosis. Differences in the extent of necrosis in rat dorsal skin flaps when different clamping times were used in RIPC were compared among the four groups described below.

METHODS

Group A was a control group in which no prior ischaemic area was created, and both back legs were devascularised for 15 min in Group B, 30 min in Group C, and 60 min in Group D. The experiments were performed on 10 rats in each group, and the surviving area was measured. One-way analysis of variance (ANOVA) and Tukey's multiple comparison test were used for analysis, with p < 0.05 regarded as significant.

RESULTS

The surviving area of the skin flap was 15.4 ± 1.8 cm(2) in Group A, 15.4 ± 2.0 cm(2) in Group B, 17.9 ± 2.0 cm(2) in Group C, and 19.2 ± 3.4 cm(2) in Group D, with significant differences between Groups A and D and between Groups B and D.

CONCLUSIONS

RIPC consisting of 60 min of ischaemic preconditioning may be clinically useful as a method of preventing skin flap necrosis.

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.

The dose-effect relationship in extracorporeal shock wave therapy: the optimal parameter for extracorporeal shock wave therapy

BACKGROUND

Extracorporeal shock wave therapy (ESWT) has been demonstrated to have the angiogenic effect on ischemic tissue. We hypothesize that ESWT exerts the proangiogenesis effect with an energy density-dependent mode on the target cells.

MATERIALS AND METHODS

Endothelial progenitor cells (EPCs) of rats were obtained by cultivation of bone marrow-derived mononuclear cells. EPCs were divided into five groups of different energy densities, and each group was furthermore subdivided into four groups of different shock numbers. Thus, there were 20 subgroups in total. The expressions of angiogenic factors, apoptotic factors, inflammation mediators, and chemotactic factors were examined, and the proliferation activity was measured after ESWT.

RESULTS

When EPCs were treated with low-energy (0.04-0.13 mJ/mm(2)) shock wave, the expressions of endothelial nitric oxide synthase, angiopoietin (Ang) 1, Ang-2, and B-cell lymphoma 2 increased and those of interleukin 6, fibroblast growth factor 2, C-X-C chemokine receptor type 4, vascular endothelial growth factor a, Bcl-2-associated X protein, and caspase 3 decreased. stromal cell-derived factor 1 changed without statistical significance. When cells were treated with high-energy (0.16 mJ/mm(2)) shock wave, most of the expressions of cytokines declined except the apoptotic factors and fibroblast growth factor 2, and cells lead to apoptosis. The proliferation activity and the ratio of Ang-1/Ang-2 reached their peak values, when cells were treated with ESWT with the intensity ranging from 0.10-0.13 mJ/mm(2) and shock number ranging from 200-300 impulses. Meanwhile, a minimal value of the ratio of Bax/Bcl-2 was observed.

CONCLUSIONS

There is a dose-effect relationship in ESWT. The shock intensity ranging from 0.10-0.13 mJ/mm(2) and shock number ranging from 200-300 impulses were the optimal parameters for ESWT to treat cells in vitro.

Extracorporeal shock waves improve angiogenesis after full thickness burn

OBJECTIVE

Extensive wounds of burn patients remain a challenge due to wound infection and subsequent septicemia. We wondered whether extracorporeal shock wave application (ESWA) accelerates the healing process. The aim of the study was to analyze microcirculation, angiogenesis and leukocyte endothelium interaction after burns by using ESWA with two types of low intensity.

METHODS

Full-thickness burns were inflicted to the ears of hairless mice (n=51; area: 1.3 mm(2)). The mice were randomized into five groups: (A) low-energy shock waves after burn injury (0.04 mJ/mm(2)); (B) very low-energy shock waves after burn injury (0.015 mJ/mm(2)); (C) mice received burns but no ESWA (control group); (D) mice without burn were exposed to low-energy shock waves; (E) mice without burns and with no shock wave application. Intravital fluorescent microscopy was used to assess microcirculatory parameters, angiogenesis and leukocyte behavior. ESWA was performed on day 1, 3 and 7 (500 shoots, 1 Hz). Values were obtained straight after and on days 1, 3, 7 and 12 post burn.

RESULTS

Group A showed accelerated angiogenesis (non-perfused area at day 12: 5.3% vs. 9.1% (group B) and 12.6% (group C), p=0.005). Both shock wave groups showed improved blood flow after burn compared to group C. Shock waves significantly increased the number of rolling leukocytes compared to the non-ESWA-treated animals (group D: 210.8% vs. group E: 83.3%, p=0.017 on day 7 and 172.3 vs. 90.9%, p=0.01 on day 12).

CONCLUSION

Shock waves have a positive effect on several parameters of wound healing after burns, especially with regard to angiogenesis and leukocyte behaviour. In both ESWA groups, angiogenesis and blood flow outmatched the control group. Within the ESWA groups the higher intensity (0.04 mJ/mm(2)) showed better results than the lower intensity group. Moreover, shock waves increased the number of rolling and sticking leukocytes as a part of an improved metabolism.

Extracorporeal shock wave treatment protects skin flaps against ischemia-reperfusion injury

Advances in the treatment of ischemia-reperfusion injury have created an opportunity for plastic surgeons to apply these treatments to flaps and implanted tissues. Using an extended inferior epigastric artery skin flap as a flap ischemia-reperfusion injury (IRI) model, we examined the capability of extracorporeal shock wave treatment (ESWT) to protect tissue against IRI in a rat flap model. Twenty-four rats were used and randomly divided into three groups (n=8 for each group). Group I was the sham group and did not undergo ischemic insult; rather, the flap was raised and immediately sutured back (non-ischemic control group). Group II (ischemia control) and Group III (ESWT) underwent 3h of ischemic insult. During reperfusion Group III was treated with ESWT and Group II was left untreated. Histological evaluation was made to investigate treatment induced tissue alterations. Survival areas were assessed at 5d postoperatively. Skin flap survival and perfusion improved significantly in the ischemic animals following ESWT (p<0.001, respectively). The tissue protecting effect of ESWT resulted in flap survival areas and perfusion data equal to non-ischemic, sham operated flaps. In line with the observation of better flap perfusion, tissue from ESWT-treated animals (Group III) revealed a significantly increased frequency of CD31-positive vessels compared to both the ischemic (Group II; p=0.003) and the non-ischemic, sham operated control (Group I; p<0.005) and an enhanced expression of pro-angiogenic genes. This was accompanied by a mild suppression of pro-inflammatory genes. Our study suggests that ESWT improves flap survival in IRI by promoting angiogenesis and inhibiting tissue inflammation. The study identifies ESWT as a low-cost and easy to use technique for surgical techniques that aim at reducing ischemia-reperfusion-induced tissue injury.