Cosmetic surgery has experienced a notable increase in popularity over recent decades, driven by societal emphasis on aesthetic appearance and significant advancements in surgical techniques (1, 2). As the demand for procedures such as rhinoplasty, facelifts, and liposuction continue to rise, ensuring optimal postoperative outcomes becomes increasingly critical (1, 3, 4). One of the primary concerns in this context is the prevention of surgical site infections (SSIs), which not only hinder patient recovery and satisfaction but also impose substantial economic burdens on healthcare systems globally (5, 6).

Traditional infection control measures, including antibiotic prophylaxis and maintaining sterile surgical environments, have been fundamental in reducing SSIs (7–9). However, the growing prevalence of antibiotic-resistant pathogens and the limitations inherent in conventional methods highlight the need for innovative strategies to enhance infection prevention in cosmetic surgeries (9, 10). Among these emerging strategies, fractional ultra-pulse CO₂ laser treatment has garnered attention for its potential role in mitigating postoperative infections (11).

Fractional ultra-pulse CO₂ laser technology, initially developed for precise tissue ablation and hemostasis, has evolved to exhibit significant antimicrobial properties (12). Unlike conventional pulsed CO₂ lasers, fractional systems deliver energy in a grid-like pattern, creating microthermal zones that promote tissue regeneration while minimizing thermal damage. The antimicrobial efficacy of fractional CO₂ lasers is attributed to their ability to disrupt microbial cell walls, denature proteins, and interfere with DNA replication, thereby inhibiting pathogen proliferation (13–15). Additionally, specific laser wavelengths fractional CO₂ lasers have been shown to promote wound healing and modulate inflammatory responses, further contributing to improved surgical outcomes (16, 17).

Empirical studies across various surgical disciplines have demonstrated the effectiveness of fractional laser treatments in reducing SSIs (18, 19). For instance, studies reported a substantial decrease in infection rates in dermatologic surgeries when fractional diode lasers were employed for preoperative skin decontamination (20, 21). Similarly, research in orthopedic and dental surgeries has shown that fractional Nd and CO₂ lasers, respectively, can lower infection rates and enhance tissue regeneration (22–24). In cosmetic procedures, the integration of laser treatments is particularly promising due to the delicate nature of tissue manipulation and extended healing periods associated with these surgeries. Unlike systemic antibiotics, fractional laser treatments offer targeted antimicrobial action with minimal side effects, aligning well with the aesthetic objectives of cosmetic surgery by minimizing scarring and promoting rapid recovery (11, 25). Moreover, the non-invasive nature of laser applications enhances patient safety and satisfaction, making it an attractive adjunctive measure in surgical protocols (26, 27).

Despite these advantages, the adoption of laser treatments in cosmetic surgery remains limited. This is primarily due to variability in laser types, dosages, and treatment parameters across different studies, which complicates the establishment of standardized protocols (28, 29). Accordingly, this multicenter retrospective cohort study was designed to determine whether a standardized three-stage fractional ultra-pulse CO₂ laser protocol reduces the incidence of superficial surgical-site infections, improves scar outcomes—quantified by thickness, elasticity, pigmentation, and vascularity—and enhances patient-reported satisfaction and health-related quality of life following elective cosmetic surgery.

This retrospective cohort study was conducted to evaluate the efficacy of fractional ultra-pulse CO₂ laser treatment in reducing post-surgical infection rates and improving aesthetic outcomes following cosmetic procedures. The investigation spanned 4 years, from January 2020 to February 2024, and involved multiple high-volume cosmetic surgery clinics across five major Chinese cities: Beijing Puhua International Hospital (Beijing), Shanghai Time Plastic Surgery Hospital (Shanghai), Guangzhou Hanfei Medical Cosmetology Hospital (Guangzhou), Xichan Hospital (Chengdu), and Xi’an Hospital of Traditional Chinese Medicine (Xi’an). These centers were selected based on their substantial caseloads, meticulous electronic medical records (EMRs), and standardized operational protocols, ensuring comprehensive and robust data collection and generalizable findings.

A total of 562 adult patients undergoing elective cosmetic procedures were included in the final cohort. The mean age was 47 ± 17 years, with females comprising 62% (n = 349). Fitzpatrick distribution comprised type II (36%), type III (33%), type IV (24%), with smaller proportions of type I (1.2%), type V (3.4%), and type VI (2.4%), reflecting the inclusion of expatriate and mixed-ancestry patients at the Beijing and Shanghai centers. Only patients with Fitzpatrick I–IV underwent the fractional ultra-pulse CO₂ laser protocol; patients with phototypes V–VI were enrolled and followed but did not receive laser exposure, forming part of the non-laser comparison arm. The mean BMI was 26.6 ± 4.8 kg/m², reflecting an overweight population. Smoking history indicated 53% former smokers, 28% current smokers, and 19% never smokers. Documented comorbidities included diabetes mellitus (9.4%) and hypertension (14%). Prior surgical exposure showed 40% with no previous operations, 36% with one, and 24% with two or more prior interventions. Allergic history was present in 20% of patients. The most common procedures included liposuction (19%), rhinoplasty and abdominoplasty (15% each), breast augmentation (13%), Botox/injectable treatments (14%), facelifts (12%), and other miscellaneous cosmetic surgeries (12%). The average duration of surgery was 183 ± 71 min, with general anesthesia employed in 71% of cases. Mean surgeon experience was 17 ± 7 years. Fractional ultra-pulse CO₂ laser treatment was applied in 324 cases (58%). All patients allocated to laser therapy underwent the full three-stage regimen—pre-incisional decontamination, immediate post-closure pass, and day-10 outpatient pass—therefore no internal dose–response subgroups existed and laser exposure was analyzed as a binary variable.

Postoperative outcomes revealed an average wound healing time of 15.1 ± 5.1 days, with median pain scores between 6 and 8. Mean serum CRP was 12.9 ± 6.6 mg/L. Objective scar assessment revealed a mean thickness of 2.73 ± 1.22 mm, elasticity of 0.76 ± 0.10 AU, melanin index of 51 ± 11, erythema index of 48 ± 11, and a collagen type III/I ratio of 1.76 ± 0.44. Adverse outcomes included infections in 33% (n = 188), hematomas in 2.3%, hypertrophic scarring in 9.6%, and keloids in 5.5%. Infections were confirmed via microbiological analysis, employing aerobic, anaerobic, fungal (Sabouraud), and mycobacterial (Löwenstein–Jensen) cultures with incubation extended up to 6 weeks for slow-growing organisms. Pathogen identification included morphological, biochemical, and MALDI-TOF mass spectrometry techniques. Pathogen-specific subgroup comparisons were not performed due to underpowered strata. Patient-reported outcomes showed 20% of respondents scored their satisfaction as 10/10, with a mean quality of life score of 82 ± 12. Mean time to resumption of daily activities was 19.1 ± 5.2 days, as shown in Table 1.

When comparing laser-treated (n = 324) versus non-laser (n = 238) patients, baseline characteristics including age, sex, skin type, BMI, smoking, diabetes, hypertension, surgical history, and procedure types were statistically comparable (all p > 0.05). The only non-significant trend was a slightly longer operative time in the non-laser group (189 ± 70 vs. 178 ± 71 min; p = 0.061). Laser-treated patients exhibited significantly superior postoperative outcomes: faster healing (13.8 ± 5.7 vs. 17.0 ± 3.2 days; p < 0.001), lower CRP levels (11.3 ± 7.4 vs. 14.9 ± 4.4 mg/L; p < 0.001), thinner scars (2.44 ± 1.39 vs. 3.14 ± 0.78 mm; p < 0.001), higher elasticity (0.85 ± 0.03 vs. 0.65 ± 0.03 AU; p < 0.001), improved pigmentation (60 ± 6 vs. 40 ± 6; p < 0.001), reduced vascularity (40 ± 6 vs. 60 ± 6; p < 0.001), and more favorable collagen remodeling (III/I ratio: 1.40 ± 0.12 vs. 2.26 ± 0.15; p < 0.001). Infection incidence was markedly reduced in the laser group (15% vs. 59%; p < 0.001), as was keloid formation (1.9% vs. 11%; p < 0.001). Satisfaction scores and quality of life were significantly higher among laser-treated patients (35% rated satisfaction as 10/10; p < 0.001; QoL: 90 ± 6 vs. 70 ± 6; p < 0.001), and they returned to normal activity sooner (17.2 ± 5.7 vs. 21.8 ± 2.7 days; p < 0.001), as shown in Table 2 and Figure 1A.

In a stratified analysis of infection status (infected n = 188 vs. non-infected n = 374), there were no significant demographic or baseline clinical differences between groups. However, infections were substantially more frequent in non-laser patients (74% of infected cases vs. 26% in the laser group; p < 0.001). Infected patients exhibited significantly delayed wound healing (16.5 ± 3.3 vs. 14.5 ± 5.6 days; p < 0.001), elevated pain (p < 0.001), increased CRP (14.3 ± 4.7 vs. 12.2 ± 7.2 mg/L; p < 0.001), greater scar thickness (3.02 ± 0.86 vs. 2.59 ± 1.34 mm; p < 0.001), reduced elasticity (0.70 ± 0.09 vs. 0.80 ± 0.09 AU; p < 0.001), diminished pigmentation (45 ± 10 vs. 55 ± 11; p < 0.001), greater erythema (55 ± 10 vs. 45 ± 10; p < 0.001), and unfavorable collagen profiles (2.02 ± 0.40 vs. 1.63 ± 0.40; p < 0.001). These patients also demonstrated significantly lower satisfaction, poorer quality of life (75 ± 11 vs. 85 ± 10; p < 0.001), and prolonged recovery (21.3 ± 3.2 vs. 18.0 ± 5.6 days; p < 0.001), as shown in Table 3 and Figure 1B.

The Kaplan–Meier survival curves demonstrating infection-free probability over a 30-day postoperative period, as shown in Figure 2. The two groups began to diverge from day 11, with the laser-treated cohort demonstrating significantly higher infection-free survival (log-rank p < 0.001). Cox proportional hazards modeling, adjusted using inverse probability treatment weighting (IPTW), showed a 72% reduced infection hazard in the laser group (HR = 0.28; 95% CI: 0.19–0.41), confirming the independent protective role of fractional CO₂ laser therapy.

Across all eight dimensions, the laser-treated group demonstrated significantly attenuated infection accumulation, with pronounced divergence in healing time, pain score, CRP levels, scar thickness, and return-to-activity duration (all p < 0.001). No significant interaction was observed for BMI (p = 0.707) or surgeon experience (p = 0.314), and operative time approached significance (p = 0.061), suggesting that laser benefits are primarily mediated through improved inflammatory modulation and tissue recovery kinetics, as shown in Figure 3.

The principal component analysis (PCA) plot is based on post-surgical recovery variables. The first three principal components (PC1 = 45.6%, PC2 = 21.5%, PC3 = 9.0%) accounted for 76.1% of total variance. Patients receiving laser treatment clustered distinctly along the positive PC1 axis, whereas non-laser patients with infections aggregated on the negative PC1 axis. Overlaying infection status further revealed co-localization of infections with the non-laser cluster. PCA loadings (not shown) indicated that CRP, healing time, scar thickness, and collagen III/I ratio were the dominant contributors to PC1 variance, reinforcing their central role in both clinical and mechanistic stratification, as shown in Figure 4.

The current study assesses the efficacy of fractional ultra-pulse CO₂ laser treatment in improving postoperative outcomes among cosmetic surgery patients. The findings demonstrate that incorporating fractional ultra-pulse CO₂ laser significantly reduces post-surgical infection rates, improves scar quality, and enhances patient satisfaction and quality of life. Infection incidence decreased from 59% in non-laser patients to 15% in those treated with laser, and inverse-probability-of-treatment–weighted Cox analysis showed a 72% lower hazard of infection (HR = 0.28; 95% CI: 0.19–0.41). These data support the emerging view that fractional ablative CO₂ laser can function as both an antimicrobial and immunomodulatory adjunct to cosmetic surgery rather than a purely aesthetic resurfacing tool. It is important to note that, although the cohort encompassed heterogeneous procedures (rhinoplasty, liposuction, breast augmentation, facelift, abdominoplasty, and injectable aesthetic interventions), the study was not powered for formal, procedure-specific comparative effectiveness analyses. Accordingly, these results should be interpreted as evidence of benefit across elective cosmetic surgery in aggregate. Future prospective work should stratify by anatomical site and operative magnitude to determine whether effect size differs, for example, between body-contouring and facial aesthetic procedures.

A pivotal observation in this multicenter cohort was the markedly lower rate of microbiologically confirmed superficial surgical-site infection in patients managed with the predefined fractional ultra-pulse CO₂ protocol. The protocolized delivery of fractional ablative energy at three fixed stages—pre-incisional decontamination, immediate post-closure ablation, and day-10 resurfacing—under RFID-locked parameters plausibly contributed to intraoperative field sterilization and early inflammatory modulation, as reflected by lower C-reactive protein levels, faster epithelialization, and more favorable collagen III/I ratios (45, 46). Prior aesthetic-surgery series typically describe low infection frequencies in single procedures (for example, isolated rhinoplasty or abdominoplasty) but rarely standardize fractional CO₂ exposure at prespecified perioperative timepoints or adjudicate SSIs with microbiology (47–49). In contrast, the present analysis, across heterogeneous cosmetic procedures, found that adding a uniform three-stage ultra-pulse CO₂ regimen to otherwise identical wound care and a fixed five-day oral cefalexin plus topical mupirocin protocol was associated with both a substantially lower aggregate superficial SSI incidence (15% vs. 59%) and a markedly lower keloid rate (1.9% vs. 11%) (49, 50). Although all patients received oral antibiotics, fractional ultra-pulse CO₂ laser treatment significantly reduced SSIs. This hypothesizes a potential for selective antibiotic de-escalation in low-risk aesthetic cases, but this retrospective finding requires prospective testing with a formal step-down protocol before it can be recommended. Laser-treated patients also showed superior scar outcomes (thinner, more elastic, better collagen), demonstrating a regenerative, antifibrotic effect consistent with “prehabilitation.” The highly structured protocol—being checklist-driven, auditable (locked presets, data logging), and credentialed—suggests it is adaptable to high-volume ambulatory centers with the required hardware, without increasing anesthesia time. In lower-resource settings without access to an ultra-pulse CO₂ platform, the wound-hygiene, standardized closure technique, and short fixed antibiotic course used here remain reproducible, whereas the fractional laser component would likely be limited to referral centers; this creates a practical pathway for staged adoption rather than an all-or-nothing requirement.

In the present study, a minor subset of participants (n = 7; 1.2%) was classified as Fitzpatrick skin type I. This observation, although uncommon in ethnically Han Chinese populations, is not implausible given the increasing cosmopolitan demographics in major Chinese metropolitan areas such as Beijing and Shanghai. However, the Shanghai’s significant influx of long-term migrants, comprising over 39% of its residents and contributing to its ethnic diversity, along with the broader presence of expatriates and multi-ethnic residents in such urban centers, enhances clinical diversity (51–53). Prior studies conducted in Southeast Asia, including Malaysia and Singapore, have documented Fitzpatrick skin types I to IV among ethnic Chinese individuals. Notably, a study analyzing skin ageing phenotypes in 3,281 ethnic Chinese participants from the Singapore/Malaysia Cross-Sectional Genetics Epidemiology Study (SMCGES) highlighted the diversity in skin types within this population (54–56). Additionally, research focusing on facial photo-ageing in 1,081 ethnic Chinese young adults from the same cohort further corroborated the variability in skin phototypes (56). These findings suggest that rare instances of type I may be noted in individuals with mixed heritage or long-term European ancestry. Furthermore, skin phototype variation may be underreported due to reliance on self-assessment rather than objective pigmentation metrics such as melanin index or spectrophotometric analysis (57, 58). This preserves internal safety but limits external generalizability. Although a minority of participants were categorized as Fitzpatrick I, reflecting the cosmopolitan case mix of large metropolitan centers, the cohort also included individuals with phototypes V–VI who, by protocol, did not receive fractional laser. The study was not powered to evaluate differential benefit within phototypes I–IV, and it cannot address pigmentary safety, dyschromia risk, or infection-modifying effects in phototypes V–VI. These results therefore support the antimicrobial and wound-modulating potential of fractional ultra-pulse CO₂ laser in lighter phototypes while underscoring the need for prospective trials deliberately enrolling and stratifying darker phototypes.

Infection confirmation in our study utilized comprehensive microbiological methods including aerobic, anaerobic, fungal (Sabouraud), and mycobacterial (Löwenstein–Jensen) cultures with extended incubation periods up to 6 weeks. Pathogens were definitively identified via morphological, biochemical, and MALDI-TOF techniques. Although specific pathogen sub-analyses were not performed due to limited sample size, these robust microbiological protocols reinforce our infection incidence findings and highlight areas for future investigation into organism-specific outcomes. Contrasting studies, reported negligible effects of fractional laser treatment on infection rates post-rhinoplasty, potentially attributable to variations in laser parameters, procedural context, or inherent anatomical microbiota (59–62). The consistency of our standardized laser protocol across varied cosmetic procedures and clinics likely enhanced our infection control outcomes compared to studies employing heterogeneous methodologies (63).

Our results showed improved scar quality in patients treated with fractional ultra-pulse CO₂ laser, manifested as thinner scars, higher elasticity, and optimized collagen III/I ratios. The fractional laser’s precise delivery of microthermal zones presumably facilitated fibroblast activation, collagen synthesis, and tissue remodeling, thereby minimizing hypertrophic scarring (64, 65). The significant improvement in scar elasticity (0.85 vs. 0.65 AU; p < 0.001) and collagen remodeling observed in the laser-treated cohort underscores the fractional laser’s capacity to modulate extracellular matrix formation effectively. Previous research indicates the critical role of laser settings in determining therapeutic outcomes, emphasizing the precision of fractional ultra-pulse lasers in minimizing thermal damage and optimizing healing (66–70).

However, mixed outcomes regarding scar improvements with laser therapies reported by various authors may stem from disparities in laser modalities, treatment timing, and anatomical site variations (52–55). Our consistent use of a postoperative laser session at 7–14 days post-surgery may represent optimal timing to influence early scar remodeling, thereby achieving superior aesthetic outcomes compared to differing protocols (71–74).

The observed attenuation of inflammatory markers (CRP levels) in our laser-treated cohort highlights the fractional laser’s systemic anti-inflammatory effects, corroborating prior evidence (75). Kaplan–Meier survival analysis reinforced this finding, showing clear divergence in infection-free survival starting from postoperative day 11, affirming the laser’s temporal protective effect against inflammation and infection. Although some studies, indicate variability in laser-induced modulation of systemic inflammation depending on parameters and modalities, our standardized settings likely produced consistent and replicable anti-inflammatory outcomes (76, 77). This highlights the necessity for standardized protocols to consistently achieve anti-inflammatory benefits across surgical contexts.

Significantly enhanced patient satisfaction and quality of life scores in our laser-treated patients align with previously reported outcomes demonstrating improved cosmetic results and rapid postoperative recovery (78–80). The reduced complications and aesthetically favorable scars likely contribute substantially to patients’ psychological well-being and overall satisfaction (80–82). Nonetheless, satisfaction inherently involves subjective patient expectations, pain thresholds, and patient-provider communication quality (81–83). Thus, integrating patient education and psychological support remains essential in maximizing subjective patient satisfaction, despite objective clinical improvements achieved through fractional laser treatment (84).

The standardized three-stage fractional ultra-pulse CO₂ laser protocol is most applicable to adults (ASA I–III, HbA1c <8.5%) undergoing elective cosmetic procedures with incisions >3 cm and no active infection, with surgeons prioritizing patients at higher theoretical risk for SSI or dysregulated scarring. Only Fitzpatrick phototypes I–IV received the laser; phototypes V–VI were enrolled but received standard care. Contraindications included connective-tissue or collagen vascular disorders, chronic systemic immunosuppression (e.g., >10 mg prednisolone-equivalent >14 days), poorly controlled multisystem disease, and Fitzpatrick phototypes V–VI for the laser component itself. While no laser-related adverse events requiring care escalation were captured, pigmentary safety in darker phototypes cannot be inferred. Operator training required a 24-h device-specific certification and 10 proctored cases, supplemented by weekly encrypted log audits and quarterly calibration, defining a formal, auditable learning curve rather than an artisanal one. This three-stage protocol (pre-incision, immediate post-closure, day-10 outpatient) was embedded into routine perioperative flow without intraoperative IV antibiotics, and all patients received the same five-day oral cefalexin plus topical mupirocin regimen. Each single-pass stage did not require a separate anesthetic session; although incremental procedure time and device costs were not prospectively recorded, future studies should quantify these resource impacts alongside downstream savings from prevented complications and fewer unplanned visits.

Several limitations warrant consideration. First, the retrospective, non-randomized design introduces inherent risks of selection bias, reliance on documentation accuracy, and residual confounding from unmeasured variables such as nutritional status and peri-operative glycemic control, despite adjustment through inverse-probability-of-treatment weighting. Second, although laser delivery was standardized using RFID-locked presets and routine device calibration, minor inter-operator variations in hand-piece angulation, pass overlap, or contact pressure may have contributed to procedural heterogeneity. Third, while superficial surgical-site infections (SSIs) were adjudicated using CDC/NHSN criteria under blinded review and confirmed microbiologically, differences in postoperative surveillance intensity across centers may have influenced detection. Fourth, although the observed reduction in microbiologically confirmed superficial SSI would be expected to translate into fewer unscheduled postoperative contacts and lower downstream wound-care costs, the retrospective extraction did not include harmonized cost data or systematically coded unplanned visits across all centers, precluding direct economic analysis. Lastly, the limited follow-up duration restricted assessment of late scar maturation and delayed infections, and the absence of pathogen-specific stratification constrained interpretation of organism-level laser effects. These findings should be validated in prospective, randomized designs with surgeon-level clustering, extended follow-up, stratified microbiological endpoints, and predefined capture of cost and unplanned utilization.

This multicenter analysis demonstrates that a predefined, auditable three-stage fractional ultra-pulse CO₂ laser protocol, delivered under RFID-locked parameters and combined with uniform perioperative wound care, was associated with markedly lower microbiologically confirmed superficial surgical-site infection rates, accelerated epithelialization, more favorable collagen remodeling, lower keloid formation, higher patient-reported satisfaction, and faster functional recovery. Internal validity is strengthened by standardized eligibility criteria, inverse-probability-of-treatment weighting, and blinded microbiological adjudication. These findings support the concept that fractional ultra-pulse CO₂ laser can serve as both an antimicrobial and regenerative adjunct in cosmetic surgery. The next essential step is a prospective, adequately powered, multicenter randomized or cluster-randomized trial with surgeon- or center-level allocation of the standardized ultra-pulse CO₂ protocol versus standard care. Such a study should (i) stratify a priori by procedure category (for example, facial aesthetic vs. body-contouring surgery), (ii) deliberately enroll Fitzpatrick phototypes V–VI to evaluate pigmentary safety and efficacy in darker phototypes, (iii) capture direct cost data and unscheduled postoperative encounters to estimate cost-effectiveness and systems impact, (iv) extend follow-up to at least 12 months to characterize long-term scar maturation and hypertrophic/keloid trajectories, and (v) include pathogen-level microbiology to test whether fractional ultra-pulse CO₂ exposure differentially suppresses specific organisms. These requirements define the evidentiary pathway for translating this protocol from observational evidence to a practice-standard infection-prevention and scar-optimization adjunct in aesthetic surgery.