Improved outcome of surgical flaps treated with topical dimethylsulfoxide

The Effect of Botulinum Toxin A on the NADPH Oxidase System and Ischemia-Reperfusion Injury

BACKGROUND

Despite the increasing popularity of various materials for ischemia-reperfusion (I/R) injury mitigation, research on botulinum toxin type A (BoNTA) remains limited. This study assesses BoNTA's efficacy in protecting flaps from I/R injury by inhibiting the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system and reducing reactive oxygen species (ROS) production.

METHODS

Seventy-six Sprague-Dawley rats were studied. We examined the effects of BoNTA on superoxide production in four rats using a lucigenin-enhanced chemiluminescence assay (LECL). Another group of 60 rats had their superficial inferior epigastric artery (SIEA) flaps treated with either BoNTA or saline and clamped for 0, 1, and 4 hours before reperfusion. Flap survival and histological outcomes were assessed five days post-operation. ROS production in SIEA flaps and femoral vessels was analyzed in 12 additional rats, post-I/R injury.

RESULTS

The LECL results showed that the BoNTA group had significantly lower superoxide production compared to controls, with notable reductions at 4 hours. While no significant differences were noted at the 0 and 1-hour marks, the 4-hour mark showed significant protective effects in BoNTA-treated groups. The survival rate was 90% for BoNTA-treated rats versus 60% for controls ( P = 0.028). Significant reductions in ROS were also observed in the 4-hour I/R group.

CONCLUSIONS

BoNTA effectively protects against I/R injury by inhibiting the NADPH oxidase system and reducing ROS levels. These results support further investigation into the specific mechanisms of NADPH oxidase inhibition by BoNTA and its potential clinical applications, given its safety profile.

CLINICAL RELEVANCE STATEMENT

The findings from the present study are expected to provide a basis for clinical studies regarding this use of BoNTA.

Risk Factors for Skin Flap and Nipple-Areolar Necrosis in Patients Undergoing Nipple-Sparing Mastectomy With Deep Inferior Epigastric Perforator Flap Reconstruction

INTRODUCTION

Nipple-sparing mastectomy (NSM) with deep inferior epigastric perforator (DIEP) flap reconstruction is a surgical option for select patients with or at risk of breast cancer. However, post-operative skin flap and nipple-areolar complex (NAC) necrosis remain common complications. This study aimed to identify factors associated with necrosis in patients undergoing NSM with DIEP reconstruction.

METHODS

A retrospective cohort study was performed from 2015 to 2023. 74 variables were analyzed in patients undergoing NSM with DIEP. Patients were stratified into 3 groups based on post-operative skin/NAC necrosis: none, partial thickness, and full thickness. Comparative and descriptive statistics were performed via t-tests, ANOVA, and chi-squared tests.

RESULTS

34 women with 31 breast cancers met inclusion. 44% experienced necrosis: 15% partial thickness and 29% full thickness. The majority were white (85.3%) with mean age of 50 years (SD = 9.11). In patients with immediate DIEP reconstruction, hypoperfused areas identified by SPY angiography increased risk of necrosis (P = .012). Approximately 50% of both partial thickness and full thickness necrosis patients had concerns on SPY angiography. Former smokers in the full thickness necrosis group had more pack years than those without necrosis (9 vs .65 pack years, P = .035).

CONCLUSION

In patients receiving NSM with DIEP flap reconstruction, those with hypoperfusion on SPY angiography and longer smoking history had higher necrosis rates. This supports the continued used of SPY angiography and the role of pre-operative counseling in former smokers with increased pack years on their risk of necrosis and the role of preventative measures in the perioperative setting.

Salvage of Nipple-Areolar Complex Ischemia With Dimethyl Sulfoxide: A Case Series

BACKGROUND

Nipple-areolar complex (NAC) necrosis is a known risk of breast surgery, particularly mastectomy. Disruption of the underlying blood supply to the NAC can lead to ischemia and subsequent necrosis. Nitroglycerin paste is currently used to combat NAC ischemia but has limited efficacy and an unfavorable side effect profile. Topical dimethyl sulfoxide (DMSO) has been shown to increase tissue perfusion in microsurgery and various skin flaps, but its role in the treatment and prevention of NAC ischemia has not been reported. Through a prospective case series, this study aims to introduce DMSO as a safe treatment for NAC ischemia after breast surgery.

METHODS

Patients treated by 2 breast surgeons and a single plastic surgeon who underwent nipple-sparing mastectomy or breast reduction and developed NAC ischemia were identified via a prospectively maintained database. Ischemic changes were diagnosed, and treatment to the affected NAC with DMSO was initiated at the conclusion of the procedure, or postoperative day 1 in most cases, and continued 4 times daily until ischemic changes had resolved clinically. Collected demographic, surgical, and outcome variables were analyzed using descriptive statistics.

RESULTS

Eleven patients with a mean age of 47.8 ± 9.5 years (range, 35-61 years) and mean body mass index of 26.0 ± 4.4 kg/m2 (range, 20.7-33.4 kg/m2) were identified. The mean duration of time between surgery and the clinical diagnosis of NAC ischemia was 1.3 ± 2.8 days (range, 0-7 days). The average length of time from DMSO initiation to clinical improvement or resolution of NAC ischemia was 7.5 ± 2.5 days (range, 5-12 days). All patients demonstrated significant improvement or complete resolution of NAC ischemia following serial topical DMSO application.

CONCLUSIONS

This study demonstrates DMSO is a safe treatment for threatened NACs. All patients in this series showed either dramatic improvement or resolution of NAC ischemia after DMSO application, and threatened NACs of all 11 patients were successfully salvaged. These promising results set the basis for ongoing randomized controlled studies to determine the efficacy of DMSO treatment for NAC ischemia.

Non-operative adjuncts for the prevention of mastectomy skin flap necrosis: a systematic review and meta-analysis

BACKGROUND

Native skin flap necrosis is a potentially devastating complication following skin-sparing or nipple-sparing mastectomy with a reported incidence of as high as 30%. Treatment depends on the depth and extent of tissue necrosis and can range from dressings to surgical debridement and further reconstruction. This can have implications on patient physical and psychological wellbeing as well as cost of treatment. This study aims to identify and appraise cost-effective non-surgical adjuncts for the prevention of native skin flap necrosis.

METHODS

A systematic review was performed using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement and structured around existing recommended guidelines. A search of MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature and ClinicalTrials.gov was performed with the medical subject headings 'mastectomy' and 'flap necrosis'. After exclusion, 12 articles were selected for review and analysed.

RESULTS

A total of 8439 mastectomies were performed on 7895 patients. Preventative non-surgical adjuncts that demonstrated statistically significant reduction in mastectomy flap necrosis included topical nitroglycerin ointment (P = 0.000), closed-Incision negative pressure wound therapy (P = 0.000), topical dimethylsulfoxide ointment (P = 0.03), oral cilostazol (P = 0.032), and local heat pre-conditioning (P = 0.047).

CONCLUSIONS

This study identifies multiple adjuncts that may aid in preventing mastectomy skin flap necrosis, especially in high-risk patients. Further studies could aim to define standardized protocols and compare the various adjuncts in different circumstances.

Topical Dimethyl Sulfoxide for Congested Nipple-areolar Complexes in Breast Surgery: A Pilot Study

Necrosis of the nipple-areolar complex (NAC) is a major complication of breast surgery that most commonly results from venous congestion. Several conservative rescue therapies have been proposed for relieving NAC congestion, but each carries certain drawbacks, including cost and side effect profile. In this study, we evaluated the effectiveness of topical dimethyl sulfoxide (DMSO), an inexpensive compound with vasodilatory, free radical scavenging, and antiinflammatory properties in rescuing congested NACs.

METHODS

We conducted a review of all 15 patients treated with DMSO for NAC congestion at our institution between May 2019 and October 2020. DMSO was applied in liquid form on a soaked gauze pad in the hospital; patients were instructed to apply a DMSO cream to the NAC twice a day following discharge. Patient characteristics and data related to DMSO treatment and NAC healing were compared via univariate analysis.

RESULTS

Eighteen congested NACs from 15 patients who underwent mastectomy, breast reduction, mastopexy, or breast reconstruction were treated with DMSO. Of the 18 treated NACs, 15 healed with DMSO treatment alone. The average length of DMSO treatment was 9.4 ± 8.5 days (mean ± standard deviation); NAC healing took place over 9.9 ± 9.6 days. There were no complications related to DMSO treatment.

CONCLUSIONS

This pilot study shows that DMSO may be an effective topical treatment for NAC congestion following breast surgery. Given its low cost, ease of application, and lack of side effects, future studies should prospectively compare DMSO against other topical treatments, like nitroglycerin ointment.

Hyperbaric oxygen treatment for mastectomy flap ischaemia: A case series of 50 breasts

INTRODUCTION

Hyperbaric oxygen treatment (HBOT) has been suggested as an effective intervention to limit necrosis of ischaemic skin flaps after mastectomy. The purpose of this study was to evaluate outcomes of HBOT in the largest series of patients to date with mastectomy flap ischaemia.

METHODS

A retrospective analysis was performed of 50 breasts requiring HBOT for mastectomy flap ischaemia. The severity of the ischaemia or necrosis was evaluated by four independent observers using the skin ischaemia necrosis (SKIN) score. Multivariate logistic regression analyses were used to assess associations between risk factors and re-operation.

RESULTS

HBOT was started a median of 3 days (range 1-23) after surgery and continued for a median of 12 sessions (range 6-22). The breast SKIN surface area scores (n = 175 observations by the independent observers) improved in 34% (of observations) and the depth scores deteriorated in 42% (both P < 0.01). Both the surface area and depth scores were associated with the need for re-operation: higher scores, reflecting more severe necrosis of the mastectomy flap, were associated with increased need for re-operation. Twenty-nine breasts (58%) recovered without additional operation. Pre-operative radiotherapy (OR 7.2, 95% CI 1.4-37.3) and postoperative infection (OR 15.4, 95% CI 2.6-89.7) were risk factors for re-operation in multivariate analyses.

CONCLUSIONS

In this case series, the surface area of the breast affected by ischaemia decreased during HBOT, and most breasts (58%) did not undergo an additional operation. A randomised control trial is needed to confirm or refute the possibility that HBOT improves outcome in patients with mastectomy flap ischaemia.

Estradiol postconditioning relieves ischemia/reperfusion injury in axial skin flaps of rats, inhibits apoptosis and alters the MKP-1/ERK pathway

Previous studies have suggested that estradiol can reduce the ischemia/reperfusion (I/R) injury in skin flaps. However, the mechanism, particularly the signal pathways involved in this protective effect are not well established. In the current study, an I/R injury model was established in rats to explore the connection between estradiol protection during I/R injury and extracellular signal‑regulated kinase (ERK) signaling. Healthy male Wistar rats were divided into five groups (n=10): Control group (group I), I/R group (group II), saline group (group III), estradiol group (group IV) and inhibitor (PD‑98059) group (group V). The survival rate of the flap was compared between groups, morphological changes were observed by hematoxylin and eosin staining of sections, and terminal deoxynucleotidyl transferase dUTP nick end labeling was performed to identify apoptotic cells and determine the apoptotic index. To further investigate the mechanism, western blot analysis was performed to assess the protein level of ERK1/2, phospho‑ERK1/2, and mitogen‑activated protein kinase phosphatase 1 (MKP‑1). The results of the present study demonstrated that estradiol therapy can reduce I/R injury and decrease the apoptosis index in an axial skin flap model. The inhibitor of the ERK pathway (PD‑98059) partially abolished the effects of estradiol, which involve the phosphatase enzyme MKP‑1. Taken together, the findings of the present study indicate that estradiol may act by reducing the expression of MKP‑1, mediating the expression/activation changes of the ERK pathway and subsequently reduce the level of apoptosis and the I/R injury the axial flap. Estrogen may be used to mitigate the adverse reaction caused by ischemia‑reperfusion injury and effectively improve the survival rate and survival quality of free skin flap and improve patient prognosis.

Effect of Systemic Antioxidant Allopurinol Therapy on Skin Flap Survival

BACKGROUND

It has been reported that systemic administration of allopurinol improves cell survival. This study was aimed to evaluate effects of allopurinol on skin flaps in dogs.

METHODS

Twenty dogs underwent one skin flap surgery with a 2-week interval. The first procedure was performed according to the standard protocols. The second phase was started by a 1-week pretreatment with allopurinol. Length of the necrotic zone was measured and recorded daily. At each phase, flaps were removed and sent for histopathological study after 1 week observation.

RESULTS

Mean length of the necrotic zone in allopurinol treated skin flaps has been significantly less than normal flaps over all 7 days of observation (p<0.0001). Histopathology study showed less inflammation and more normal tissue structure in the allopurinol treated skin flaps.

CONCLUSION

It was demonstrated that systemic administration of allopurinol significantly improved skin flap survival.

Modulation of influenza vaccine immune responses using an epidermal growth factor receptor kinase inhibitor

Systemic use of epidermal growth factor receptor inhibitors (EGFRIs) has been shown to alter MHC expression and that of several chemokines, and to enhance immune cell recruitment into human skin. We hypothesized that EGFRIs may have value as cutaneous immune response modifiers, and determined the effects of topical application of an irreversible EGFRI on a well-established murine model of influenza vaccination. We found that a single topical application of an EGFRI led to increased levels of antibodies that inhibit influenza mediated hemagglutination and viral cytopathic effects. The topically applied EGFRI significantly enhanced the generation of vaccine-specific IL-4 and IFN-γ producing cells within skin-draining lymph nodes as early as one week following vaccination. The EGFRI/vaccine group showed a twelve-fold reduction in detectable pulmonary viral load four days after infection as compared to the vaccine alone control group. The reduction in the lung viral titers correlated with the survival rate, which demonstrated 100% protection in the EGFRI/vaccine immunized group but only 65% protection in the mice immunized with vaccine alone. These findings are significant because they demonstrate that inhibition of defined signaling pathways within the skin using small molecule kinase inhibitors provides a novel approach to enhance immune responses to vaccines.

Effects of dextran-40 on flap viability after modified radical mastectomy

BACKGROUND

Postoperative management of patients after modified radical mastectomy has evolved over the past decades. In the early postoperative period, wound complication rates were reported to be as high as 60%. Flap necrosis after modified radical mastectomy is a common problem encountered by surgeons. Various treatment strategies have been proposed in the literature but none have addressed the use of dextran-40.

OBJECTIVE

To determine whether dextran-40 infusion improves skin flap viability after modified radical mastectomy.

METHODS

Twenty-eight patients who underwent modified radical mastectomy were randomly assigned to receive dextran-40 or no dextran-40 intraoperatively after flap dissection. Patients were followed prospectively over a five-year period in a community hospital. The incidence of postmastectomy skin flap necrosis and prognosis of the necrotic area after dextran-40 infusion was observed.

RESULTS

Flap necrosis was observed in five (17.8%) patients. Hypertension and diabetes mellitus were found to be risk factors for the development of flap necrosis (P<0.05). Flap thickness and tension on the flaps were found to be related to flap necrosis. Six of seven patients with flap perfusion problems (ecchymosis or necrosis) underwent dextran-40 treatment and healed without graft replacement.

CONCLUSIONS

Dextran-40 treatment did not affect development of flap necrosis. However, if necrosis had already developed, the necrotic area of the skin flaps improved with dextran-40 treatment.

Hypothyroidism improves random-pattern skin flap survival in rats

BACKGROUND

The protective effect of hypothyroidism against ischemic or toxic conditions has been shown in various tissues. We investigated the effect of propylthiouracil (PTU)/methimazole (MMI)-induced hypothyroidism and acute local effect of MMI on the outcome of lethal ischemia in random-pattern skin flaps.

MATERIALS AND METHODS

Dorsal flaps with caudal pedicles were elevated at midline and flap survival was measured at the seventh day after surgery. The first group, as control, received 1 mL of 0.9% saline solution in the flap before flap elevation. In groups 2 and 3, hypothyroidism was induced by administration of either PTU 0.05% or MMI 0.04% in drinking water. The next four groups received local injections of MMI (10, 20, 50, or 100 μg/flap) before flap elevation. Local PTU injection was ignored due to insolubility of the agent.

RESULTS

Hypothyroidism was induced in chronic PTU- and MMI-treated groups, and animals in these groups showed significant increase in their flap survival, compared to control euthyroid rats (79.47% ± 10.49% and 75.48% ± 12.93% versus 52.26% ± 5.75%, respectively, P < 0.01). Acute local treatment of skin flaps with MMI failed to significantly affect the flap survival.

CONCLUSION

This study demonstrates for the first time that hypothyroidism improves survival of random-pattern skin flaps in rats.

Distinct effects on M2-type pyruvate kinase are involved in the dimethylsulfoxide-induced modulation of cellular proliferation and degranulation of mast cells

Dimethylsulfoxide (DMSO), a universal solvent, is frequently used to dissolve various classes of chemicals for the evaluation of their biological activities. In one such evaluation, we noticed that DMSO itself caused cellular proliferation and interfered with high affinity IgE receptor (FcepsilonRI)-mediated degranulation of mast cells. DMSO caused cellular proliferation of RBL-2H3 cells by phosphorylating both extracellular-signal regulated kinase (ERK) and M2-type pyruvate kinase (M2PK) through which the enzymatic activity of M2PK was reduced. Allergenic activation of FcepsilonRI caused the tyrosine phosphorylations of signaling components of FcepsilonRI, such as Syk, PLCgamma1, PLCgamma2, ERK, and M2PK. In these allergenic activated RBL-2H3 cells, DMSO specifically inhibited FcepsilonRI-mediated tyrosine phosphorylation of M2PK, blocked FcepsilonRI-mediated inhibition of the enzymatic activity of M2PK, and then inhibited FcepsilonRI-mediated degranulation. These results suggest that DMSO causes cellular proliferation and mast cell degranulation through differential modulation of M2PK in resting and allergenic activated cells.

Ação do dimetil-sulfóxido na isquemia de retalhos randômicos de pele em ratos

Objetivo: Avaliar a ação do dimetil-sulfóxido (DMSO) na necrose distal de retalhos randômicos isquêmicos em ratos. Métodos: Foram utilizados 30 ratos machos, linhagem Wistar, peso entre 220 e 363g e idade média de 3 meses. O retalho cutâneo dorsal (8x2cm) com pedículo cranial foi descolado, reposto em seu leito e suturado com poliamida 4.0. O grupo controle-CT (n=10) não recebeu nenhuma medicação, o grupo simulado-SM (n=10) recebeu o volume de 1mL de solução salina subcutânea, dividida em dez aplicações ao longo do retalho, o grupo experimento-EX (n=10) recebeu a injeção de 1ml de DMSO 5%. Após sete dias foram avaliadas as áreas de necrose distal e colhido material para o estudo histológico. Resultados: As medidas das áreas de necrose (CT=47,99, SM=58,78, EX=41,57) e as porcentagens das áreas de necrose (CT=29,98, SM=36,73, EX=23,99) mostraram-se menores no grupo Ex (p< 0,05). O estudo histológico qualitativo mostrou, no grupo Ex, maior presença de neovascularização, menor desestruturação dos anexos e do estroma conjuntivo e presença de fibroblastos em período mais precoce que nos dois outros grupos. Conclusão: O DMSO teve ação benéfica sobre os retalhos cutâneos randômicos em ratos, expressos pela menor área de necrose distal e pelo aspecto histológico de reparação tecidual mais precoce.

Pharmacologic Enhancement of Rat Skin Flap Survival with Topical Oleic Acid

This study was instituted to investigate in a rat model the effect of topical coadministration of the penetration enhancer oleic acid (10% by volume) and RIMSO-50 (medical grade dimethyl sulfoxide, 50% by volume) on rat skin flap survival. A rectangular abdominal skin flap (2.5 x 3 cm) was surgically elevated over the left abdomen in 40 nude rats. The vein of the flap's neurovascular pedicle was occluded by placement of a microvascular clip, and the flap was resutured with 4-0 Prolene to its adjacent skin. At the end of 8 hours, the distal edge of the flap was reincised to gain access to the clips and the clips were removed. After resuturing of the flap's distal edge to its adjacent skin, the 40 flaps were randomly divided into four groups. Group 1 (control) flaps were treated with 5 g of saline, group 2 (dimethyl sulfoxide) flaps were treated with 2.7 g of dimethyl sulfoxide (50% by volume), group 3 flaps (oleic acid) were topically treated with 0.45 g of oleic acid (10% by volume), and group 4 (dimethyl sulfoxide plus oleic acid) flaps were treated with a mixture of 0.45 g of oleic acid (10% by volume) and 2.7 g of dimethyl sulfoxide (50% by volume) diluted in saline. Each flap was topically treated with 5 ml of drug-soaked gauze for 1 hour immediately after clip removal to attenuate reperfusion injury. Thereafter, drug was applied topically once daily for 4 more days. Digital photographs of each flap were then taken on day 6 and the flaps were then harvested. The percentage of skin survival in each flap was determined by computerized morphometry and planimetry. The mean surviving area of group 3 (oleic acid-treated flaps) was 23.60 +/- 4.19 percent and was statistically higher than that in group 1 (control, saline-treated flaps) at 7.20 +/- 2.56 percent. The mean surviving area of group 2 (dimethyl sulfoxide-treated flaps) at 18.00 +/- 5.23 percent and group 4 (oleic acid- and dimethyl sulfoxide-treated flaps) at 9.90 +/- 3.44 percent did not achieve statistically higher mean surviving areas than controls. A topical solution of oleic acid (10% by volume) caused a statistically significant increase in the survival of rat abdominal skin flaps relative to controls. Dimethyl sulfoxide and the two experimental drugs together did not increase the percentage of flap survival when given as a single 5-ml dose released from a surgical sponge at reperfusion for 1 hour and then daily for a total of 5 days. The reasons for the lack of response are unknown but may have included the technical difficulty of delivering an adequate dose of dimethyl sulfoxide topically and immiscibility between dimethyl sulfoxide and oleic acid. Further studies may be warranted.

Effect of allopurinol, superoxide-dismutase, and hyperbaric oxygen on flap survival

The effect of allopurinol, superoxide-dismutase, and hyperbaric oxygen was compared on axial pattern skin flap survival. An abdominal flap based on the inferior epigastric pedicle was raised in rats for this purpose. Three experimental groups were studied. In the first group, adult male Wistar rats received 50 mg/kg I.P. of allopurinol. The second received 20,000 I.U./kg of superoxide-dismutase. The third group was submitted to hyperbaric oxygen therapy. The flaps were exposed to 8-h warm ischemia. Flap survival was evaluated on postoperative day 7. All flaps survived, and the mean survival areas were 63.53%, 83.03%, and 55.98%, respectively, in the allopurinol, superoxide-dismutase, and hyperbaric groups. The percentage of flap necrosis was significantly smaller in all experimental groups when compared to controls (P < 0.05). It was clear that the superoxide-dismutase group had better results on axial pattern ischemic skin flap survival, under the tested conditions. The tested methods improved flap survival to ischemic injury, and the flap designed is a reliable model for further investigations.