BACKGROUND:Basic fibroblast growth factor(bFGF)can promote production of collagen,fibronectin and matrix enzyme in healing wounds.However,dysregulation of this process,such as the abnormal coordination of cell proliferation,extracellular.matrix and neovasculadzation formation,or remodeling of the wound matrix will lead to excess accumulation of scar tissues.OBJECTIVE:To investigate effects of bFGF on normal skin wound healing and hypertrophic scar formation.METHODS:Normal and hypertrophic scar fibroblasts from tissue biopsies from 5 patients who underwent plastic surgery for repairing hypertrophic scars were isolated and cultured.The expressions of collagen,fibronectin and protein synthesis were detected by RT-PCR and ELISA.The mitochonddal membrane potential changes were measured using JC-1 staining and flow cytometry.Simultaneously,adenosine tdphosphate(ATP)levels were determined by chemiluminescence method.The effects of bFGF on these indexes of normal and hypertrophic scar fibroblasts were observed.RESULTS AND CONCLUSION:Hypertrophic scar fibroblasts become slower after being exposed to bFGF,which selectively inhibited type Ⅰ collagen production in hypertrophic scar fibroblasts(P<0.05).Although bFGF inhibited type]collagen production,it had no effect on type Ⅲ collagen expression in both normal and hypertrophic scar fibroblasts.However,fibronectin expression in the normal fibroblasts was up-reguleted after bFGF treatment(P<0.05).In addition,the mitochonddal membrane potential tended to depolarization,although no statistical difference,in hypertrophic scar fibroblasts treated with bFGF(10 or 100 μg/L).bFGF treatment increased the cellular ATP levels in the normal fibroblasts,while there were no significant alterations in the hypertrophic scar fibroblasts over a treatment of bFGF(10 or 100 μg/L,P<0.05).The results suggest that there are differential effects and mechanisms on the skin fibroblasts with bFGF treatment in normal wound healing and hypertrophic scar formation.

BACKGROUND:The osmotic tissue expander is a self-fil ing device consisting of an osmotic active hydrogel which is made of vinylpyrrolidone and mehtylmethacrylate. It can absorb body fluids and swel up gradual y after embedded.
OBJECTIVE:To explore the short-term and long-term regular patterns as wel as histocompatibility of the osmotic tissue expander in vivo.
METHODS:A self-control design was carried out in Wistar rats by embedding the osmotic tissue expander and high-density polyethylene into each side of their spinal column subcutaneously. Wound healing, tissue expansion and inflammatory reaction were detected and compared at different periods after operation.
RESULTS AND CONCLUSION:Al the wounds got primary healing. The device expanded fastest at week 1 after the implantation. After being enlarged to about nine times that of the initial size at week 4, the expander slowed down its swel ing. It reached its ultimate volume at week 12 which was about 10 times as big as that of the initial one. Then it remained almost the same size until the end of our design. Pathological sections showed that the inflammatory reaction of osmotic-tissue-expander-group had no significant difference from that of the control group (P>0.05). These findings suggest that osmotic tissue expander has a slow-lasting swel ing ability and good histocompatibility.

Objective:To recognize the characteristics of necrotizing fasciitis patients complicated with sepsis and summarize the experience the treatment.Methods:A retrospective study was conducted. The clinical data of 57 patients with necrotizing fasciitis complicated with sepsis admitted to Guangdong Provincial People's Hospital from July 2009 to December 2019 was analyzed by collecting such factors as gender, age, complications, infection sites, pathogens, surgery information, treatment options and outcome. The patients were divided into debridement group ( n = 14) and control group ( n = 43) according to whether the debridement was completed within 48 hours of admission, and the mortality during hospitalization between the two groups was compared. A telephone follow-up had been done to record the long-term outcome of these patients. Results:Among 57 patients with necrotizing fasciitis complicated with sepsis, there were 43 males and 14 females with the average age of (57.9±12.1) years old. Most of the underlying diseases were diabetes mellitus (70.17%), other diseases included hypertension (8.77%), tumor chemotherapy (7.02%), liver disease (hepatitis, cirrhosis, 7.02%), coronary artery heart disease (3.51%), systemic lupus erythematosus (3.51%), etc. Most of the infection site was lower limbs (71.93%). There were 78 pathogens cultured in 57 patients, in which 52 were non-drug resistant bacteria (66.67%), and 26 were drug resistant bacteria (33.33%). There were 40 Gram positive (G +) bacteria (51.28%), 29 Gram negative (G -) bacteria (37.18%), 8 fungi (10.26%) and 1 mixed bacteria (1.28%). Finally, of 57 patients, 46 patients were cured, and 11 patients died with hospital mortality of 19.30%. Among 57 patients, the hospital mortality in the debridement group was significantly lower than that in the control group [0% (0/14) vs. 25.58% (11/43), P < 0.05]. Among the 46 cured patients, 11 had accepted amputations, accounting for 23.91%. In December 2020, 43 patients who were cured (3 patients were lost to follow-up) were followed up by telephone. Twenty-three patients were completely self-care, 9 patients were partly self-care, 8 patients were completely unable to take care of themselves, and 3 patients died. Conclusions:Necrotizing fasciitis with sepsis mostly occurs in people with weakened immunity, and has a high mortality and disability rate. Early identification and active surgical debridement may be the key to improve the treatment effect.

Objective To investigate the potential protective effects of valproic acid (VPA) on gut barrier function after major burn injury in rats and its mechanism.Methods Forty male Sprague-Dawley (SD) rats were divided into sham + normal saline (NS),sham + VPA,scald + NS,and scald + VPA groups,with 10 rats in each group.Rat with 55％ total body surface area (TBSA) third-degree severe-bums model was reproduced by immersing into 80 ℃ water,and the rats in sham groups were given sham-bums by immersing into 37 ℃ water.The rats after severebums were immediately treated with 0.25 mL of 300 mg/kg VPA or NS by subcutaneous injection.Rats were sacrificed at 2 hours and 6 hours after injury,and abdominal aortic blood and ileal tissue were harvested.The levels of vascular endothelial growth factor (VEGF) were determined by enzyme-linked immunosorbent assay (ELISA).The intestinal permeability was evaluated by fluorescein isothiocyanate-dextran (FITC-dextran) determination.The histomorphological changes in gut barrier were evaluated by Chiu grading system.Levels of acetylated lysine at the ninth position of histone 3 protein (Ac-H3K9),hypoxia-inducible factor 1α (HIF-1α),zona occludens 1 (ZO-1) and myosin light chain kinase (MLCK) were determined by immunofluorescence staining and Western Blot.Results Compared with sham + NS group,rats in scald + NS group showed intestinal mucosal damage 2 hours after bum injury,as well as increased mucosal permeability,protein expression levels of HIF-1 α,VEGF,MLCK,and lowered levels of AC-H3K9 and ZO-1.These changes were much more prominent at 6 hours after injury.VPA treatment significantly attenuated the bum-induced intestinal damage.Compared with scald + NS group,the protective effects in scald + VPA group was not evident at 2 hours after injury;however,intestinal damage was much less severe at 6 hours after injury (Chiu score:2.03 ± 0.27 vs.3.12 ± 0.15),intestinal permeability was significantly decreased [FITC-dextran (μg/L):709 ± 76 vs.1138 ± 75],histone acetylation was enhanced [Ac-H3K9 (gray value):1.55 ± 0.12 vs.0.48±0.12],ZO-1 degradation was significantly inhibited (gray value:0.69 ± 0.12 vs.0.43 ± 0.16),the protein expression levels of VEGF and MLCK were significantly down-regulated [VEGF (ng/mg):51.7±3.7 vs.71.2±4.3,MLCK (gray value):1.98±0.20 vs.2.80±0.24],while the HIF-1 α protein expression levels were significantly reduced at both 2 hours and 6 hours after injury (gray value:2.50±0.39 vs.3.88±0.42 at 2 hours,1.83±0.42 vs.4.42±0.41 at 6 hours,all P ＜ 0.05).Conclusions Severe bum injury can induce histone deacetylation,ZO-1 degradation and intestinal barrier dysfunction.VPA can improve the levels of histone acetylation and ZO-1,and protect intestinal epithelial barrier function.These may probably be mediated through inhibiting HIF-1α and its downstream gene VEGF and MLCK.

Objective:To investigate the clinical features and prognostic influencing factors of toxic epidermal necrolysis (TEN).Methods:A retrospective observational study was conducted. From January 2008 to March 2019, a total of 46 TEN patients who met the inclusion criteria were admitted to Guangdong Provincial People's Hospital. The gender, age, and hospital admission diagnosis of the 46 patients, the category of department admitted of patients complicated with sepsis, death ratio of the sepsis patients with or without treatment history in intensive care unit (ICU)/department of burns and wound repair, and the cause of death of the deceased patients were recorded. Depending on whether complicated with sepsis, the patients were divided into sepsis group (32 cases) and non-sepsis group (14 cases). According to whether died or not, the patients were divided into death group (9 cases) and survival group (37 cases). The specific conditions of suspected pathogenic agents and combined underlying diseases, the abnormality of transaminase/bilirubin, creatinine, and platelet count in blood on admission, and the detection of pathogenic microorganisms and drug resistance during the course of disease of patients were recorded in both sepsis group and non-sepsis group. The gender, age, lesion area, severity of illness score for TEN (SCORTEN) system score, combined underlying diseases on admission, and blood microbial culture positivity, hormone use, and gamma globulin use during the course of disease of patients between sepsis group and non-sepsis group, death group and survival group were compared respectively. Data were statistically analyzed with chi-square test, Fisher's exact probability test, and Mann-Whitney U test. The factors with statistically significant differences between sepsis group and non-sepsis group, death group and survival group were selected for binary multivariate logistic regression analysis, so as to screen the independent risk factors affecting sepsis and death in TEN patients. Results:Of the 46 TEN patients, 30 were male and 16 were female, aged from 8 months to 92.0 years, with 11 cases (23.91%) of epidermolysis bullosa, 9 cases (19.57%) of exfoliative dermatitis, 9 cases (19.57%) of TEN, 7 cases (15.22%) of epidermolysis bullosa, 6 cases (13.04%) of Stevens-Johnson syndrome, and 4 cases (8.70%) of severe drug rash for hospital admission diagnosis. The patients complicated with sepsis were admitted to 11 departments, and the death ratio of patients with treatment history in ICU/department of burns and wound repair was similar to that of patients without such department treatment history ( P>0.05). All the deceased patients were complicated with sepsis, which was also the main cause of death. On admission, the suspected pathogenic agents of patients in sepsis group were mainly allopurinol (8 cases) and non-steroidal anti-inflammatory drugs (4 cases), while those in non-sepsis group were allopurinol (3 cases) and psychotropic drugs (3 cases). Patients in sepsis group combined as many as 10 underlying diseases, while those in non-sepsis group combined only 4 underlying diseases. The proportions of patients with increased creatinine ( χ2=13.349, P<0.01) and decreased platelet count ( P<0.01) in sepsis group were significantly higher than those in non-sepsis group, while the transaminase/bilirubin abnormality was similar to that in non-sepsis group ( P>0.05). A wide variety of pathogens were detected in the blood, respiratory tract secretions, and skin secretions of 21 patients in sepsis group, and 14 patients were infected with drug-resistant bacteria; among the 9 strains cultured from the blood samples, 8 were drug-resistant bacteria and 6 were Gram-positive bacteria. In non-sepsis group, pathogens were detected in blood, respiratory tract secretions, and skin secretions of 8 patients, with fewer species, and 6 patients were infected with drug-resistant bacteria. The gender, age, lesion area, blood microbial culture positivity, hormone use, and gamma globulin use of patients in sepsis group were similar to those in non-sepsis group ( P>0.05). The proportion of patients combined with underlying diseases ( χ2=4.493, P<0.05) and the proportion of patients with SCORTEN system score of 4-6 points ( P<0.01) of patients in sepsis group were significantly higher than those in non-sepsis group. The gender, combined underlying diseases, lesion area, blood microbial culture positivity, hormone use, and gamma globulin use of patients were similar between survival group and death group ( P>0.05). The proportion of patients with age≥60 years and the proportion of patients with SCORTEN system score of 4-6 points of patients in death group were significantly higher than those in survival group ( χ2=4.412, 11.627, P<0.05 or P<0.01). The SCORTEN system score was an independent risk factor affecting sepsis and death in TEN patients (odds ratio=3.025, 2.757, 95% confidence interval=1.352-6.769, 1.244-6.110, P<0.05 or P<0.01). Conclusions:The diagnosis of TEN is difficult on admission. Male population is susceptible to TEN, and allopurinol is the common pathogenic agent. The proportion of patients combined with underlying diseases is high in TEN patients complicated with sepsis, with mainly drug-resistant bacteria and mostly Gram-positive bacteria in blood-borne infections. The deceased patients are older than the survived, and the main cause of death is sepsis. The SCORTEN system score is an independent risk factor affecting sepsis and death in TEN patients.

Objective: To explore the effects of allogeneic bone marrow mesenchymal stem cells (BMSCs) on polarization of peritoneal macrophages isolated from rats with sepsis induced by endotoxin/lipopolysaccharide (LPS). Methods: (1) BMSCs were isolated, cultured and purified from 5 SD rats with whole bone marrow adherent method. The third passage of cells were collected for morphologic observation, detection of expressions of stem cell surface markers CD29, CD44, CD45, and CD90 with flow cytometer, and identification of osteogenic and adipogenic differentiation. (2) Another 45 SD rats were divided into sham injury group (SI, n=5), LPS control group (LC, n=20), and BMSCs-treated group (BT, n=20) according to the random number table. Rats in groups LC and BT were injected with LPS (5 mg/kg) via tail vein to induce sepsis; rats in group SI were injected with the same amount of normal saline to simulate the damage. At post injury hour (PIH) 1, rats in group BT were given 1 mL BMSCs (2×10⁶/mL) via tail vein injection; rats in another two groups were injected with equal volume of phosphate buffer saline. Five rats in group SI at PIH 24 and in groups LC and BT at PIH 6, 12, 24, and 48 were sacrificed to harvest lung tissue for pathological observation with HE staining. In addition, rats in group SI at PIH 24 and in groups LC and BT at PIH 24 and 48 were simultaneously performed with intraperitoneal injection of low-glucose DMEM. Then peritoneal fluid was harvested to culture peritoneal macrophages. Flow cytometer was used to assess the positive expression of cell makers of macrophages including CD68 (making gate), CD11c, and CD206 in group SI at PIH 24 and in groups LC and BT at PIH 24 and 48. Data were processed with one-way analysis of variance and LSD test. Results: (1) The third passage of cells showed uniform fiber-like shape similar to fibroblasts. These cells showed positive expressions of CD29, CD44, CD90 and weak positive expression of CD45. They were able to differentiate into osteoblasts and adipocytes. These cells were identified as BMSCs. (2) At PIH 24, the structure of pulmonary alveoli of rats in group SI was clear and complete with no congestion or inflammatory cell infiltration. At PIH 6, the structure of pulmonary alveoli of rats in groups LC and BT was clear with a small amount of inflammatory cell infiltration, slight congestion and pulmonary interstitial thickening. At PIH 12, the inflammatory responses in lung tissue of rats in group LC were more severe than those in group BT with a large amount of inflammatory cell infiltration, serious congestion, and obvious pulmonary interstitial thickening. The pathological results of rats in group BT at PIH 12 was consistent with the results at PIH 6. At PIH 24, the pathological results of rats in groups LC and BT were similar to the results at PIH 12. At PIH 48, the structure of pulmonary alveoli tissue of rats in group LC was still severely disrupted, with a large number of inflammatory cell infiltration and congestion in lung tissue, but pulmonary interstitial thickening was slightly alleviated than before. The condition of rats in group BT nearly recovered to that in group SI. (3) At PIH 24, the positive expression rate of CD11c in peritoneal macrophages of rats in group LC [(83±10)%] was close to that in group BT [(87±7)%, P>0.05], and they were both significantly higher than the rate in group SI [(55±12)%, with P values below 0.01]. The positive expression rate of CD11c in peritoneal macrophages of rats in group LC [(59±11)%] at PIH 48 was close to that in group SI at PIH 24 (P>0.05), and they were both significantly higher than the rate in group BT [(20±11)%] at PIH 48 (with P values below 0.01). At PIH 24, the positive expression percentages of CD206 in peritoneal macrophages of rats were similar among the three groups (with P values above 0.05). The positive expression percentage of CD206 in peritoneal macrophages of rats in group SI at PIH 24 was close to that in group BT at PIH 48 (P>0.05), and they were both significantly lower than the percentage in group LC at PIH 48 (with P values below 0.01). Conclusions BMSCs can reduce the pathological inflammatory responses in the lung of rats with sepsis and inhibit peritoneal macrophages from polarizing into M1 phenotype, whereas they can not promote macrophages to polarize into M2 phenotype.

Objective:To analyze the clinical characteristics of patients with Vibrio vulnificus infection, share diagnosis and treatment experience, and establish a rapid diagnosis procedure for this disease. Methods:This study was a retrospective case series study. From January 2009 to November 2022, 11 patients with Vibrio vulnificus infection who met the inclusion criteria were admitted to the Department of Burns and Wound Repair of Guangdong Provincial People's Hospital Affiliated to Southern Medical University. The gender, age, time of onset of illness, time of admission, time of diagnosis, route of infection, underlying diseases, affected limbs, clinical manifestations and signs on admission, white blood cell count, hemoglobin, platelet count, C-reactive protein (CRP), alanine transaminase (ALT), aspartate transaminase (AST), creatinine, procalcitonin, albumin, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and blood sodium levels on admission, culture results and metagenomic next-generation sequencing (mNGS) results of pathogenic bacteria and the Vibrio vulnificus drug susceptibility test results during hospitalization, treatment methods, length of hospital stay, and outcomes of all patients were recorded. Comparative analysis was conducted on the admission time and diagnosis time of patients with and without a history of exposure to seawater/marine products, as well as the fatality ratio and amputation of limbs/digits ratio of patients with and without early adequate antibiotic treatment. For the survived patients with hand involvement, the hand function was assessed using Brunnstrom staging at the last follow-up. Based on patients' clinical characteristics and treatment conditions, a rapid diagnosis procedure for Vibrio vulnificus infection was established. Results:There were 7 males and 4 females among the patients, aged (56±17) years. Most of the patients developed symptoms in summer and autumn. The admission time was 3.00 (1.00, 4.00) d after the onset of illness, and the diagnosis time was 4.00 (2.00, 8.00) d after the onset of illness. There were 7 and 4 patients with and without a history of contact with seawater/marine products, respectively, and the admission time of these two types of patients was similar ( P>0.05). The diagnosis time of patients with a history of contact with seawater/marine products was 2.00 (2.00, 5.00) d after the onset of illness, which was significantly shorter than 9.00 (4.25, 13.00) d after the onset of illness for patients without a history of contact with seawater/marine products ( Z=-2.01, P<0.05). Totally 10 patients had underlying diseases. The affected limbs were right-hand in 8 cases, left-hand in 1 case, and lower limb in 2 cases. On admission, a total of 9 patients had fever; 11 patients had pain at the infected site, and redness and swelling of the affected limb, and 9 patients each had ecchymosis/necrosis and blisters/blood blisters; 6 patients suffered from shock, and 2 patients developed multiple organ dysfunction syndrome. On admission, there were 8 patients with abnormal white blood cell count, hemoglobin, and albumin levels, 10 patients with abnormal CRP, procalcitonin, and NT-proBNP levels, 5 patients with abnormal creatinine and blood sodium levels, and fewer patients with abnormal platelet count, ALT, and AST levels. During hospitalization, 4 of the 11 wound tissue/exudation samples had positive pathogenic bacterial culture results, and the result reporting time was 5.00 (5.00, 5.00) d; 4 of the 9 blood specimens had positive pathogenic bacterial culture results, and the result reporting time was 3.50 (1.25, 5.00) d; the mNGS results of 7 wound tissue/exudation or blood samples were all positive, and the result reporting time was 1.00 (1.00, 2.00) d. The three strains of Vibrio vulnificus detected were sensitive to 10 commonly used clinical antibiotics, including ciprofloxacin, levofloxacin, and amikacin, etc. A total of 10 patients received surgical treatment, 4 of whom had amputation of limbs/digits; all patients received anti-infection treatment. The length of hospital stay of 11 patients was (26±11) d, of whom 9 patients were cured and 2 patients died. Compared with that of the 6 patients who did not receive early adequate antibiotic treatment, the 5 patients who received early adequate antibiotic treatment had no significant changes in the fatality ratio or amputation of limbs/digits ratio ( P>0.05). In 3 months to 2 years after surgery, the hand function of 8 patients was assessed, with results showing 4 cases of disabled hands, 2 cases of incompletely disabled hands, and 2 cases of recovered hands. When a patient had clinical symptoms of limb redness and swelling and a history of contact with seawater/marine products or a pre-examination triage RiCH score of Vibrio vulnificus sepsis ≥1, the etiological testing should be initiated immediately to quickly diagnose Vibrio vulnificus infection. Conclusions:Vibrio vulnificus infection occurs most frequently in summer and autumn, with clinical manifestations and laboratory test results showing obvious infection characteristics, and may be accompanied by damage to multiple organ functions. Both the fatality and disability ratios are high and have a great impact on the function of the affected limbs. Early diagnosis is difficult and treatment is easily delayed, but mNGS could facilitate rapid detection. For patients with red and swollen limbs accompanied by a history of contact with seawater/marine products or with a pre-examination triage RiCH score of Vibrio vulnificus sepsis ≥1, the etiological testing should be initiated immediately to quickly diagnose Vibrio vulnificus infection.

OBJECTIVETo investigate the effect of bone marrow mesenchymal stem cells (BMSCs) on secretion of inflammatory cytokines in macrophages stimulated by lipopolysacharide (LPS).

METHODSRat BMSCs and macrophages were isolated, cultured, and identified. The BMSCs and macrophages, cultured alone or in co-culture, were treated with LPS or PBS or without treatment and tested for interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α) concentrations in the supernatants at 1, 3, 5, 7, 12, and 24 h after the treatment using enzyme-linked immunosorbent assay.

RESULTSExposure to LPS caused significantly increased IL-10 and TNF-α concentrations in the supernatant of cultured macrophages but not in BMSC culture. Macrophages co-cultured with BMSCs showed significantly lowered IL-10 and TNF-α secretions in response to LPS exposure as compared with the macrophages cultured alone.

CONCLUSIONBMSCs can reduce LPS-induced secretion of inflammatory cytokines by the macrophages to ameliorate inflammatory reactions.

Animals ; Cells, Cultured ; Coculture Techniques ; Enzyme-Linked Immunosorbent Assay ; Inflammation ; Interleukin-10 ; secretion ; Lipopolysaccharides ; Macrophages ; secretion ; Mesenchymal Stromal Cells ; cytology ; Rats ; Tumor Necrosis Factor-alpha ; secretion

To investigate the effect of venous super drainage applying in free flaps. Methods From June, 2017 to December, 2018, 7 cases who had severe soft tissue injuries were treated with free flap. Cause of injury: 1 electric injuries, 2 tumor-related wounds, 1 deep burns, 2 mechanical trauma, and 1 necrotizing fasciitis. All patients were underwent free flap transplantation. There were 5 cases of anterolateral thigh artery perforator flap, 1 case of superficial circumflex iliac artery perforator flap, and 1 case of first dorsal metatarsal artery perforator flap.The application of venous super-drainage technology was carried out according to needs and specific conditions. Two sets of venous passages were prepared in both recipient and donor site to form a double set of venous reflux super-drainage mode. Blood supply, swelling, exudation, secondary exploration and survival rate of the flap were observed after operation, and regularly followed-up. Results All 7 flaps survived. Venous super drainage technique was ap-plied in 7 cases. No arteriovenous crisis occurred after the operation. The flaps had good blood circulation, slight swelling, less exudation, rapid edema regression and no secondary surgical exploration. Followed-up for 2-18 (average 10.5) months, there was no infection recurred. Flaps survived well, and the donor sites healed well without sensory loss.The flexion and extension function of joint was normal. Conclusion The technique of venous super-drainage prepares 2 sets of venous systems for the free flap in the treatment of vascular pedicle in the free flap repair operation, which is conducive to reducing the venous crisis after flap surgery, reducing flap edema, reducing exudation, reducing secondary surgical exploration and improving the survival rate of the flap.

Objective:To investigate the effects of antibacterial absorbable suture closure in the repair of small range of bone defect wounds due to deep sternal wound infection after median thoracotomy.Methods:This study was a retrospective non-randomized clinical controlled study. A total of 32 patients (20 males and 12 females, aged (58±11) years) who met the inclusion criteria and underwent closure with antibacterial absorbable sutures (hereinafter referred to as direct closure surgery) admitted to Guangdong Provincial People's Hospital of Southern Medical University (hereinafter referred to as our hospital) from October 2017 to December 2021 were included in direct closure group. A total of 39 patients (27 males and 12 females, aged (59±11) years) who met the inclusion criteria and received bilateral pectoralis major muscle flap packing repair admitted to our hospital from January 2015 to January 2020, were included in muscle flap packing group. In the two groups, sternal infected wounds were thoroughly debrided during stage Ⅰ surgery, followed by wound repair during stage Ⅱ surgery. The width of sternal cross-section defects after debridement was less than 1 cm for patients in the two groups. For patients in direct closure group, stage Ⅱ wound repair involved intermittent sutures to the anterior sternal plate or full-thickness sternum with a total of 6 or 7 double sternal sutures. Relevant data including the duration of the stage Ⅱ wound repair surgery and the volume of blood loss during surgery, length of hospital stay, and bacterial wound infection of patients in the two groups were recorded. The postoperative complications and wound healing of patients in the two groups were recorded. During follow-up, the wound infection or recurrence of patients in the two groups and the sternal healing of patients in direct closure group were observed.Results:Compared with those in muscle flap packing group, the duration of stage Ⅱ wound repair surgery and length of hospital stay of patients in direct closure group were significantly shorter (with t values of 13.61 and 6.25, respectively, P<0.05), and there was no statistically significant difference in intraoperative blood loss volume of the stage Ⅱ wound repair surgery between the two groups ( P>0.05). The main bacterial infection in the two groups was Staphylococcus. In direct closure group, one patient had exudation in the wound two weeks post-operation, however the wound healed well after two weeks of conservative dressing changes; the wounds of the other patients healed well. In muscle flap packing group, 5 patients had postoperative complications, of which one patient died, and the wounds of 4 patients healed after dressing change or reoperation; the wounds of the other patients healed well. There was no statistically significant difference in complication incidence of patients between the two groups ( P>0.05). During the follow-up of 22-45 months, there was no re-infection or recurrence in the wound of patients in direct closure group and surviving patients in muscle flap packing group, the sternum of patients in the direct closure group achieved anatomical union. Conclusions:Direct closure surgery can not only effectively repair sternal cross-sectional defects with width below 1 cm due to deep sternal wound infections after median thoracotomy, but can also significantly shorten the operation time and duration of hospitalization.