Celastrol enhances the viability of random-pattern skin flaps by regulating autophagy through the AMPK-mTOR-TFEB axis.

In reconstructive and plastic surgery, random-pattern skin flaps (RPSF) are often used to correct defects. However, their clinical usefulness is limited due to their susceptibility to necrosis, especially on the distal side of the RPSF. This study validates the protective effect of celastrol (CEL) on flap viability and explores in terms of underlying mechanisms of action. The viability of different groups of RPSF was evaluated by survival zone analysis, laser doppler blood flow, and histological analysis. The effects of CEL on flap angiogenesis, apoptosis, oxidative stress, and autophagy were evaluated by Western blot, immunohistochemistry, and immunofluorescence assays. Finally, its mechanistic aspects were explored by autophagy inhibitor and Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) inhibitor. On the seventh day after surgery, the survival area size, blood supply, and microvessel count of RPSF were augmented following the administration of CEL. Additionally, CEL stimulated angiogenesis, suppressed apoptosis, and lowered oxidative stress levels immediately after elevated autophagy in ischemic regions; These effects can be reversed using the autophagy inhibitor chloroquine (CQ). Specifically, CQ has been observed to counteract the protective impact of CEL on the RPSF. Moreover, it has also been discovered that CEL triggers the AMPK-mTOR-TFEB axis activation in the area affected by ischemia. In CEL-treated skin flaps, AMPK inhibitors were demonstrated to suppress the AMPK-mTOR-TFEB axis and reduce autophagy levels. This investigation suggests that CEL benefits the survival of RPSF by augmenting angiogenesis and impeding oxidative stress and apoptosis. The results are credited to increased autophagy, made possible by the AMPK-mTOR-TFEB axis activation.

[Modern integrated approach to surgical treatment of patients with defects and deformations following high-voltage electrical injury]. / Sovremennyi kompleksnyi podkhod v khirurgicheskom lechenii patsientov s defektami i deformatsiyami v rezul'tate vysokovol'tnoi elektrotravmy.

OBJECTIVE: To develop the algorithm for correction of defects following high-voltage electrical trauma with revascularized autografts, to assess the incidence and risk factors of postoperative complications. MATERIAL AND METHODS: Surgical interventions were performed in 16 men. Autografts were selected considering localization of defect and preoperative ultrasound data on perfusion of donor and recipient areas. We applied a sample with temporary compression of the vessels and ultrasound scanning of arteries and veins (a small-sized Doppler sound indicator of blood flow velocity - MINIDOP, BIOSS). RESULTS: Nine patients underwent microsurgical transplantation of revascularized flaps. Six patients with electrical trauma of the upper extremities underwent transplantation of free skin autografts and transposition of flexor and extensor muscles of the fingers in various combinations. In 1 patient, simultaneous microsurgical graft transplantation and plasty with local tissues were carried out. Microsurgical transplantation of thoracodorsal flap was performed in 2 patients with maxillofacial defect (with preliminary deepidermization of the flap in one case). In 3 patients with traumatic amputation of the penis, 2 patients underwent phalloplasty with a thoracodorsal flap and prefabrication of a radial forearm graft at the first stage. At the next stage, urethroplasty with a prefabricated radial forearm graft was performed. In 1 patient, closure of the penis defect was carried out using scrotal flaps. CONCLUSION: An integrated surgical approach, the use of free revascularized autografts and adequate postoperative management ensure high-quality aesthetic and functional restoration, improvement of the quality of life and social adaptation of patients with defects and deformations following high-voltage electrical injury.

Comparison of the efficacy of multiple antioxidant and hyperbaric oxygen treatments in the prevention of ischemia and necrosis of local random McFarlane skin flap.

OBJECTIVE: The aim of this study was to compare the efficacy of multiple antioxidant (Proxeed Plus (PP) with Carnitine, Selenium, Zinc, Coenzyme Q10, Vitamin C, Folic Acid, Vitamin B12) on local random skin flap healing with the hyperbaric oxygen (HBO) therapy. METHODS: Fourty rats were equally divided into five groups (Control, PP, HBO, HBO + PP, PP + HBO + PP). Local random McFarlane skin flap was applied to all rats. Following the applications, evaluations were made biochemical (TAS, TOS, OSI, IL-1ß, IL-6, TNF-α, TGF-ß, VEGF) and histopathological parameters. RESULTS: Necrosis percentage was found to be lower in the PP + HBO + PP group than all other groups whereas the necrosis percentages of PP and HBO groups were similar. Oxidative stress rates were significantly higher in the control group compared to the other groups whereas it was lower in the PP + HBO + PP group than all other groups. The inflammation parameters were the highest in the control group and the lowest in the PP + HBO + PP group. Growth factors were higher in the PP + HBO + PP group than all other groups. Epithelialization and wound healing were better in the HBO and PP groups than in the control group. The greatest healing, epithelialization and vascularization was seen in the PP + HBO + PP group. The histopathological findings in the PP + HBO + PP group were better in each inner region than in the other groups. CONCLUSION: Biochemical and histopathological parameters have shown that PP reduces ischemia and necrosis and increases oxygenation in flap healing by providing significant improvement thanks to the multiple molecular structures in its content.

The effect of hyperbaric oxygen on compromised grafts and flaps.

The use of grafts and flaps serves as an integral tool in the armamentarium of the reconstructive surgeon. Proper planning and surgical judgment are critical in the ultimate success of these procedures. However, there are situations when grafts and/or flaps can become compromised and require urgent intervention for salvage. These instances can include irradiated or otherwise hypoxic wound beds, excessively large harvested grafts, random flap ischemia, venous or arterial insufficiency, and ischemia-reperfusion injury. Alternatively, compromised grafts and flaps can be inadvertently created secondary to trauma. It is in these types of cases, hyperbaric oxygen (HBO2) therapy can serve as a useful adjunct in the salvage of compromised flaps and grafts. This review outlines the extensive basic science and clinical evidence available in support of the use of HBO2 therapy for compromised grafts and flaps. The literature demonstrates the benefit of adjunctive HBO2 therapy for multiple types of grafts and flaps with various etiologies of compromise. HBO2 therapy can enhance graft and flap survival by several methods including decreasing the hypoxic insult, enhancing fibroblast function and collagen synthesis, stimulating angiogenesis and inhibiting ischemia-reperfusion injury. The expedient initiation of hyperbaric oxygen therapy as soon as flap or graft compromise is identified maximizes tissue viability and ultimately graft/flap salvage.

Angiogenic and anti-inflammatory properties of azadirachtin A improve random skin flap survival in rats.

Random skin flaps are widely used to repair tissue defects. However, the distal flap regions are prone to ischemic necrosis, limiting clinical applications. Azadirachtin A, a fruit extract from the neem, improves tissue blood supply and metabolism, reduces cell swelling, promotes tissue healing, and prevents venous thrombosis. We explored whether it enhances random skin flap survival. Fifty-four Sprague-Dawley rats were divided into control, low-dose, and high-dose Azadirachtin A-treated groups using a random number table. We used an improved version of the McFarlane technique to create flaps. On day 2, superoxide dismutase and malondialdehyde levels were measured. Tissue slices prepared on day 7 were stained with hematoxylin and eosin. The expression levels of vascular endothelial growth factor (VEGF), toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-kB), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were immunohistochemically assayed. Microcirculatory blood flow was measured via laser Doppler blood flowmetry. Flap angiography was performed using the lead-oxide gelatin injection technique. And the azadirachtin A groups exhibited a greater mean flap survival area, an improved mean blood vessel density, a greater blood flow, and higher superoxide dismutase and VEGF levels, especially at the high dose. Azadirachtin A markedly reduced the levels of TNF-α, IL-6, IL-1ß, TLR4, and NF-kB. These findings suggest that azadirachtin A promotes random skin flap survival by improving the blood supply, reducing tissue inflammation, and inhibiting flap ischemia reperfusion injury.

Hyperbaric Oxygen Therapy for Large Composite Grafts: An Alternative in Pediatric Facial Reconstruction.

BACKGROUND: Management of pediatric facial defects can be challenging, as reattachment of large composite grafts is usually unsuccessful. Hyperbaric oxygen therapy (HBO) has been researched to augment composite graft survival, but clinical use for this application remains anecdotal. The authors present their successful experience managing select cases with large composite grafts and HBO as an adjunct. METHODS: A retrospective chart review identified children presenting with facial defects and managed operatively with large composite grafts (≥1.5 × 1.5 cm) and HBO therapy. Records were reviewed for defect characteristics, management details, and outcomes at last follow-up. RESULTS: Nine children (avg. 8.4 years, range 1.6-15.1) presented with ear or nose defects secondary to dog bites (n=7), falls (n=1), or congenital causes (n=1). Three experienced ear amputations, and six suffered nasal avulsions of varying degrees. All avulsed ears were reattached. Three cases of nose avulsions were reattached; the other three underwent secondary reconstruction with composite ear grafts. HBO was initiated immediately and continued for 8-10 days. All grafts survived at least 80% with no postoperative complications. At last follow-up (avg. 30.1 months; 0.8-63.9), all patients demonstrated good cosmetic results with minimal residual deformity. CONCLUSION: When reconstruction of pediatric facial defects warrants a large chondrocutaneous graft, immediate postoperative HBO therapy can increase survival. Particularly when reattaching amputated segments, if successful, this approach offers an anatomically ideal result without donor site morbidity. If unsuccessful, it does not "burn bridges" and decreases the extent of secondary reconstruction. The authors present their HBO protocol along with a review of available literature.

The Effect of Shu Xue Tong Treatment on Random Skin Flap Survival via the VEGF-Notch/Dll4 Signaling Pathway.

Objective: To determine the effect of Shu Xue Tong treatment on random skin flap survival. Methods: Twenty-four male Sprague-Dawley (SD) rats were administered Shu Xue Tong or normal saline. On postoperative day 7, flap survival area, flap angiogenesis angiography, blood flow and vascular endothelial growth factor (VEGF), Notch1, and Delta-like ligand 4 (Dll4) expression were assessed. Results: The mean flap survival area, blood vessel regeneration, microcirculatory flow, and expression of VEGF were enhanced with Shu Xue Tong treatment relative to the control. However, in Shu Xue Tong-treated rat flap, Notch1 and Dll4 levels were significantly reduced. Conclusions: These results demonstrate the beneficial action of Shu Xue Tong on random skin flap survival and suggest that its mechanism of action involves the promotion of angiogenesis via the VEGF-Notch1/Dll4 signaling pathway.

Use of hyperbaric oxygen therapy for tissue ischemia after breast reconstruction.

INTRODUCTION: Mastectomy skin flap necrosis represents a significant complication of breast reconstructive procedures and is reported to occur in 30%-52% of patients undergoing breast reconstruction. Early identification of ischemia and early initiation of hyperbaric oxygen (HBO2) therapy can mitigate the effects of ischemia and rescue otherwise non-viable breast flap tissue. METHODS: We retrospectively examined the outcomes of HBO2 therapy in eight breasts with compromised mastectomy skin flaps between September 2015 and January 2017. Indocyanine green angiography (ICGA) was used to assess perfusion intraoperatively and post-HBO2 administration. RESULTS: Seven patients were referred for HBO2 within 24 hours of mastectomy. One patient failed to improve despite starting hyperbaric treatment within 24 hours. All other patients manifested successful healing of their mastectomy skin flaps with acceptable cosmesis after 10 HBO2 treatments. The mean relative perfusion of the at-risk area was 13.8% (±3.7%) pre-HBO2 and 101.6% (±37.3%) post-HBO2. The average area at-risk pre-HBO2 was 17.1 cm2 and reduced to zero post-HBO2. Relative perfusion values after HBO2 were found to be 6.8 (±3.4) times greater than those measured prior to HBO2. CONCLUSIONS: A short course of HBO2 may be sufficient to successfully rescue at risk post-mastectomy breast flaps. ICGA is a useful adjunct for evaluating post-mastectomy breast flap perfusion before and after HBO2 therapy.

The beneficial effects of subcutaneous Allium cepa injection on random flap survival in rats.

Random flaps are frequently used in the practice of reconstructive surgery. The aim of this experimental study was to investigate the effects of Allium cepa on random flap survival in rats. Fourteen Wistar rats were used for this experimental study. The subjects were divided into experiment and control groups. Rats in the experiment group received daily injections of A. cepa extract for 7 d before the elevation of the flaps. Following the treatment period, elevation and reinsertion of the dorsal flaps were performed. Necrotic and total flaps areas were marked and calculated 7 d after the flap elevation. Histological examinations and microangiography were performed to evaluate the results. The mean value of the proportion of necrotic flap areas to the total flap area was 25.06 and 50.6% in the A. cepa and control group, respectively (p = .0079). In the histological examination, number of vessels identified in the dermis were 23.75 ± 0.7 and 33.75 ± 9 in the A. cepa and control group, respectively (p = .7457). In angiographic images, vessels formations were more noticeable in the A. cepa group. We conclude that preoperative subcutaneous A. cepa injection increases dorsal flap survival in rats.

Extending Applications of Local Anesthesia Without Tourniquet to Flap Harvest and Transfer in the Hand.

The authors' experience demonstrates that wide-awake flap surgery in the hand is safe. The authors used this approach in 4 commonly used flaps in the hand in 27 patients: the extended Segmuller flap, the homo-digital reverse digital artery flap, the dorsal metacarpal artery perforator flap, and the Atasoy advancement flap. Wide-awake flap surgery works very well and safely achieved excellent anesthetic and vasoconstrictive effects in the authors' cases. The authors found that vasoconstriction caused by epinephrine mainly affects the capillaries and does not affect digital arteries and their major branches in the hand.

Healing Heel Ulcers in High-Risk Patients: Distally Based Peroneus Brevis Muscle Flap Case Series.

The purpose of this study was to demonstrate use of a distally based peroneus brevis muscle flap in high-risk patients with diabetes and peripheral vascular disease for limb salvage of nonhealing heel ulcerations. Seventeen patients were referred for a below-knee amputation because of nonhealing heel ulcerations and peripheral vascular disease. As a last resort, 17 distally based peroneus brevis muscle flaps were elevated in 17 patients with full-thickness heel ulcerations measuring an average defect size of 14.11 cm2. All flaps were supplemented with concentrated bone marrow aspirate, negative pressure wound therapy, bilayer wound matrix, and static external fixation for an average time of 10.3 weeks. Split-thickness skin graft was delayed by an average of 17.5 days. All procedures were performed on patients diagnosed with diabetes, advanced peripheral arterial disease and a nonhealing heel ulcer present >1 year. All flaps survived at 1.5 years follow-up. The average time to healing was 10.3 weeks. No major amputations were performed to date. Partial tip necrosis occurred in 2 patients and healed uneventfully with local wound care. Distally based peroneus brevis muscle flaps in patients with diabetes and peripheral vascular disease offer a reliable alternative to limb salvage for full-thickness heel ulcerations measuring up to 7 × 6 cm. Combinatorial procedures are necessary to improve outcomes in high-risk patients whose alternative is a major amputation.

Flap Preconditioning with the Cyclic Mode (Triangular Waveform) of Pressure-Controlled Cupping in a Rat Model: An Alternative Mode to the Continuous System.

BACKGROUND: Improving flap survival is essential for successful soft-tissue reconstruction. Although many methods to increase the survival of the distal flap portion have been attempted, there has been no widely adopted procedure. The authors evaluated the effect of flap preconditioning with two different modes (continuous and cyclic) of external volume expansion (pressure-controlled cupping) in a rat dorsal flap model. METHODS: Thirty rats were randomly assigned to the control group and two experimental groups (n = 10 per group). The continuous group underwent 30 minutes of preconditioning with -25 mmHg pressure once daily for 5 days. The cyclic group received 0 to -25 mmHg pressure for 30 minutes with the cyclic mode once daily for 5 days. On the day after the final preconditioning, caudally based 2 × 8-cm dorsal random-pattern flaps were raised and replaced in the native position. On postoperative day 9, the surviving flap area was evaluated. RESULTS: The cyclic group showed the highest flap survival rate (76.02 percent), followed by the continuous and control groups (64.96 percent and 51.53 percent, respectively). All intergroup differences were statistically significant. Tissue perfusion of the entire flap showed similar results (cyclic, 87.13 percent; continuous, 66.64 percent; control, 49.32 percent). Histologic analysis showed the most increased and organized collagen production with hypertrophy of the attached muscle and vascular density in the cyclic group, followed by the continuous and control groups. CONCLUSION: Flap preconditioning with the cyclic mode of external volume expansion is more effective than the continuous mode in an experimental rat model.

Injection of SVF combined with HBO2 improves viability of unfavorably designed flaps.

PURPOSE: Soft-tissue reconstruction is complicated by ischemia and reperfusion injury. Animal trials have documented the independent healing benefits of hyperbaric oxygen preconditioning (HBOP) and stem cell delivery in cutaneous flaps. We explored the role of HBOP and stem cell delivery in flap preconditioning and survival. METHODS: We designed a randomized controlled trial to assess the effects of hyperbaric oxygen preconditioning and stromal vascular fraction (SVF) delivery on flap survival. Of the first 24 guinea pigs, six received neither HBOP nor injections, and six underwent HBOP without injections. Of the remaining 12 animals, six received SVF or saline injections in the absence of HBOP. The final six animals received autologous SVF injections or saline injections followed by four HBOP treatments. To enhance clinical relevance, a group of 6 animals underwent HBOP prior to SVF or saline injections. Thereafter, an unfavorably designed cutaneous flap was elevated and assessed via study-blinded observer, as well as by quantification of TUNEL-positive cells. RESULTS: Distal necrosis of the tissue flap was more extensive in the no-intervention group (45% of flap). Flaps treated with HBOP only and those treated with SVF injections demonstrated only 38.2% and 27.1% distal necrosis. The most significant difference occurred in the combination HBOP and SVF group, where distal necrosis was only 21.1% of the flap (p ≤ 0.05). SVF delivery immediately prior to flap elevation further minimized distal necrosis of the flap to 15.6%. These findings were mirrored by the TUNEL assay. CONCLUSIONS: Combining HBOP and SVF improves flap viability.

Effect of 810 nm Near-Infrared Laser on Revascularization of Ischemic Flaps in Rats.

OBJECTIVE: To investigate the effect of 810 nm near-infrared (NIR) laser on the revascularization of ischemic flaps. BACKGROUND: It has long been proved that photobiomodulation therapy (PBMT) improves the blood supply of flaps. NIR laser improves the treatment of hypodermis-located lesions and of flap survival, but basic research on the use of 810 nm NIR laser for ischemic flap revascularization is still lacking. MATERIALS AND METHODS: We prepared two symmetrical long random-pattern flaps on the backs of 60 rats. Each flap was 6 cm long, 1 cm wide, and 1 cm to the middle line. The flaps were divided into an irradiated flap group and an internal control group. The irradiated flaps underwent postoperative 810 nm laser therapy with the energy density of 11.30 J/cm2 daily. The control flaps were covered by stainless steel to avoid laser irradiation. We observed the viability of the flaps. The flaps underwent Hematoxylin and Eosin (H&E) staining for the observation of histomorphology, immunohistochemical staining of factor VIII for the capillary count, α-smooth muscle actin for the small arterial count, and vascular endothelial growth factor for the integrated optical density (OD) of the positive stained color. RESULTS: The irradiated flaps showed significantly better flap survival than the control flaps. H&E staining showed that the irradiated flaps had clear tissue structure and little inflammatory cell infiltration. The control flaps demonstrated comparatively worse results. Vascular endothelial growth factor staining showed that the difference in integrated OD between the irradiated flaps and the control flaps was not statistically significant. α-smooth muscle actin and factor VIII staining showed significantly greater numbers of arterioles and capillaries in the irradiated flaps than the control flaps after 4 days of irradiation. CONCLUSIONS: PBMT with 810 nm NIR laser could enhance ischemic flap revascularization and increase flap viability.

Random flap survival with hyperbaric oxygen: daily versus twice-daily treatments.

PURPOSE: Hyperbaric oxygen (HBO2) therapy is used to improve the survival of compromised flaps. Compromised flaps are complications encountered postsurgically, or in traumatic degloving or avulsion injuries. Failed flaps lead to persistence of the defect, requirement of another donor site, and psychosocial sequelae. Although evidence of the benefit of HBO2 therapy is significant, there is no consensus on the optimal treatment regimen. The purpose of this study is to examine whether twice-daily treatments (BID HBO2) provide additional benefit compared to daily treatments (QD HBO2) in a rat compromised random flap model. METHODS: A rat random flap model was used with subjects divided into three groups: 1) control group; 2) QD HBO2; and 3) BID HBO2, where HBO2 was performed with 100% oxygen at 2.5 atmospheres absolute/ATA (253 kPa) for 90 minutes. After 10 days, areas of flap necrosis were measured and biopsies were taken for histologic analysis. Statistical analysis was performed using ANOVA and paired t-tests. A P-value ⟨0.05 was considered significant. RESULT: Both treatment groups had significantly increased mean flap survival compared to controls (P⟨0.05). There was no significant difference in flap survival between the QD and BID groups. Capillary proliferation in the QD group was increased compared with controls. CONCLUSION: Both QD and BID HBO2 protocols can significantly decrease random flap necrosis. However, the results of this study suggest there is no additional benefit gained with BID treatments. Clinical studies are warranted to confirm these findings and assist in formalization of protocols for the use of HBO2in treating compromised random flaps.

[Effects of combined natural hirudin and hyperbaric oxygen therapy on survival of transplanted random-pattern skin flap in rats].

Objective: To investigate the effect of natural hirudin combined with hyperbaric oxygen therapy on the survival of transplanted random-pattern skin flap in rats. Methods: A random-pattern skin flap in size of 10.0 cm×2.5 cm was elevated on the dorsum of 72 Sprague Dawley rats. Then the 72 rats were randomly divided into 4 groups ( n=18) according to the therapy method. At immediate and within 4 days after operation, the rats were treated with normal saline injection in control group, normal saline injection combined with hyperbaric oxygen treatment in hyperbaric oxygen group, the natural hirudin injection in natural hirudin group, and the natural hirudin injection combined with hyperbaric oxygen treatment in combined group. The flap survival was observed after operation, and survival rate was evaluated at 6 days after operation. The skin samples were collected for histological analysis, microvessel density (MVD) measurement, and evaluation of tumor necrosis factor α (TNF-α) expression level by the immunohistochemical staining at 2 and 4 days after operation. Results: Partial necrosis occurred in each group after operation, and the flap in combined group had the best survival. The survival rate of flap was significantly higher in hyperbaric oxygen group, natural hirudin group, and combined group than that in control group, and in combined group than in hyperbaric oxygen group and natural hirudin group ( P<0.05). There was no significant difference between hyperbaric oxygen group and natural hirudin group ( P>0.05). At 2 days, more microvascular structure was observed in hyperbaric oxygen group, natural hirudin group, and combined group in comparison with control group; while plenty of inflammatory cells infiltration in all groups. At 4 days, the hyperbaric oxygen group, natural hirudin group, and the combined group still showed more angiogenesis. Meanwhile, there was still infiltration of inflammatory cells in control group, inflammatory cells in the other groups were significantly reduced when compared with at 2 days. At 2 days, the MVD was significantly higher in hyperbaric oxygen group, natural hirudin group, and combined group than that in control group ( P<0.05); the expression of TNF-α was significantly lower in hyperbaric oxygen group, natural hirudin group, and combined group than that in control group ( P<0.05). There was no significant difference in above indexes between hyperbaric oxygen group, natural hirudin group, and combined group ( P>0.05). At 4 days, the MVD was significantly higher in hyperbaric oxygen group, natural hirudin group, and combined group than that in control group, in natural hirudin group and combined group than in hyperbaric oxygen group ( P<0.05). The expression of TNF-α was significantly lower in hyperbaric oxygen group, natural hirudin group, and combined group than that in control group, in combined group than in natural hirudin group and hyperbaric oxygen group ( P<0.05). Conclusion: Hyperbaric oxygen and natural hirudin therapy after random-pattern skin flap transplantation can improve the survival of flaps. Moreover, combined therapy is seen to exhibit significant synergistic effect. This effect maybe related to promotion of angiogenesis and the reduction of inflammation response.

Optimal Epinephrine Concentration and Time Delay to Minimize Perfusion in Eyelid Surgery: Measured by Laser-Based Methods and a Novel Form of Extended-Wavelength Diffuse Reflectance Spectroscopy.

OBJECTIVE: This study investigates the hypoperfusion effects of epinephrine in local anesthesia in eyelid surgery. A novel form of extended-wavelength diffuse reflectance spectroscopy was evaluated. METHODS: Blood perfusion in porcine eyelid flaps was measured using laser Doppler velocimetry and laser speckle contrast imaging, whereas the tissue response was measured using diffuse reflectance spectroscopy with a broad spectrum (450-1550 nm). Epinephrine was either injected cumulatively, 0.1 (1:10,000,000), 1.0 (1:1,000,000), 10 (1:100 000), and 100 µg/ml (1:10 000), to determine the dose-response relation, or given as a single dose (10 µg/ml). Control experiments were performed with saline or lidocaine. RESULTS: Increasing concentrations of epinephrine resulted in a gradual decrease in tissue perfusion, measured by laser Doppler velocimetry and laser speckle contrast imaging, approaching a minimum after the injection of 10 µg/ml. Similar tissue response was observed with diffuse reflectance spectroscopy. The time from the injection of epinephrine (10 µg/ml) to the stabilization of hypoperfusion was 75 seconds. After administration of 10 µg/ml epinephrine, about 20% of the blood perfusion remained, supporting the use of epinephrine in eyelid flaps with a narrow pedicle. CONCLUSIONS: 10 µg/ml epinephrine appears to be adequate for vasoconstriction before oculoplastic surgery. Incisions need only be delayed for about 1 minute. Extended-wavelength diffuse reflectance spectroscopy appears to be a promising technique for monitoring the tissue response following changes in blood perfusion in plastic surgery reconstructions. However, more rigorous validation of the technique is required before it can be implemented in clinical practice.

Effects of Traditional Chinese Medicine, Dilong Injection, on Random Skin Flap Survival in Rats.

BACKGROUND: Dilong injection as a medicinal preparation extracted from earthworm in traditional Chinese medicine, is used to activate blood circulation and remove blood stasis. In this research, we aim to investigate its potential effect on random skin flap survival in rat models. MATERIALS AND METHODS: McFarlane flaps were established in 60 male Sprague-Dawley rats randomly divided into two groups: the control group and the Dilong injection group. Diong injection group was injected with the Diong injection (4 mL/kg) once a day for seven days, and the control group was given an equal volume of saline solution. After seven days, flaps were obtained and stained with Hematoxylin and Eosin. Histological examination was done to determine changes in histology such as thickness of granulation tissue, tissue edema, neutrophil infiltration, and the microvascular density (MVD). In addition, immunohistochemical detection was carried out to show vascular endothelial growth factor (VEGF) expression level. RESULTS: Compared with the control group, the Dilong group exhibited more fibroblastic proliferation, thinner neutrophil infiltration with less edema through histological examination. The MVD and the VEGF expression of flaps were significantly higher. The mean superoxide dismutase activity was evidently higher in the Dilong group than in the control group, while the mean MDA level was lower. CONCLUSIONS: According to the comparison made between the two groups for histological and immunohistochemical evaluation, the Dilong injection group has potential effects on the survival of random skin flaps in rat models.