Introduction

Recently, rib remodeling has gained popularity as an esthetic body contouring technique, particularly among patients seeking slimmer waists, enhanced thoracic definition, and a harmonious overall silhouette. Notable techniques described include ultrasound-assisted indentation surgery of the torso (UUAIST), rib osteosynthesis stabilization (RIBOSS), and selective resection of the floating ribs.^1–3

Beyond purely esthetic enhancement, a growing number of patients undergo these interventions for specific purposes, such as bodily feminization or aligning thoracic contour with gender identity. As such, rib reduction or remodeling techniques have been employed to reduce the waist-to-hip ratio (WHR) and accentuate traditional feminine features.⁴ Despite the increasing clinical adoption of these techniques, literature remains scarce, consisting mainly of case series, with no integrated evaluation of the efficacy, safety, and functional impact in healthy adults undergoing procedures solely for esthetic purposes.²

Recent studies indicate that both patients and surgeons have a positive perception of these procedures, with high esthetic satisfaction and low rates of severe short-term events.^1–3 However, methodological heterogeneity and the lack of comparative controls and standardized clinical, functional, and esthetic outcomes limit the interpretation of available results and hinder the establishment of these techniques as evidence-based practices.¹ Aspects such as postoperative quality of life and subjective perception of improvement remain scarcely addressed, despite the existence of validated scales (e.g., BODY-Q) recommended for measuring psychosocial outcomes.⁵ Additionally, objective data on functional impact, such as long-term spirometric parameters, remain scarce.¹

To the best of our knowledge, this systematic review is the first to exclusively synthesize evidence regarding rib remodeling performed solely for esthetic purposes in healthy adults, comparing techniques, presenting objective ranges of reduction (when reported), and organizing complications according to documented incidence. Unlike previous reviews that included heterogeneous populations or reconstructive contexts, the present study focuses solely on esthetic procedures, allowing a more precise assessment of efficacy and risks. We aim to fill a critical gap by providing a structured synthesis that supports clinical decision-making, guides surgical practice, and informs the development of future guidelines.

Materials and Methods

The present systematic review of the literature adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)⁶ and the guidelines set by the International Committee of Medical Journal Editors (ICMJE) for preparing scientific manuscripts.

The guiding question was structured using the population, intervention, comparison, outcome (PICO) framework.⁷ The population (P) included adults with no thoracic disease; the intervention (I) comprised rib remodeling techniques performed for purely esthetic purposes; the comparison (C), when applicable, involved either no intervention or a comparison between different surgical approaches; and the outcomes (O) encompassed waist circumference reduction, WHR, esthetic satisfaction, surgical complications, and technical feasibility.

We conducted a systematic search of Public Medical Literature (PubMed)/Medlars online (MEDLINE), Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), and the Cochrane Library, covering all available publications up to April 28, 2025. The search strategy combined free terms and descriptors using Boolean operators, including rib remodeling, esthetic rib resection, floating rib removal, waist reduction surgery, rib contouring, body contouring surgery, greenstick fracture, rib osteotomy, rib reshaping, and thoracic feminization. Supplementary Material 1 shows the complete search strategy, including detailed descriptors and Boolean operators for each database.

Inclusion criteria encompassed studies reporting procedures performed exclusively for esthetic purposes, involving adults (≥ 18 years) of any gender or gender identity, with no history or diagnosis of thoracic disease. Eligible studies included those describing greenstick fractures, monocortical osteotomies, piezotomies, or selective resection of floating ribs, with study designs comprising clinical trials (randomized or non-randomized), prospective or retrospective cohorts, or case series with up to five patients.

We included articles reporting at least one of the following outcomes: waist circumference reduction, WHR change, assessment of body symmetry, patient satisfaction, or complication rates. We only considered articles published in English or Spanish that were available as full texts. Exclusion criteria comprised studies with reconstructive purposes, populations under 18 years, patients with thoracic or significant pulmonary disease, cases of functional thoracic reconstruction, series with fewer than five patients, and articles not accessible in full text.

Two independent reviewers conducted the screening in two stages: first by reading titles and abstracts, and then by evaluating the full text of potentially eligible studies. The assessment of inter-rater agreement utilized Cohen’s kappa coefficient (κ = 0.82), which indicates a near-perfect level of concordance.

Assessment methods were objective (e.g., measurement of abdominal circumference, WHR, standardized imaging) or subjective (self-reported outcomes, surgeon evaluation, spontaneous satisfaction). Additionally, when applicable, standardized tools for psychosocial assessment in esthetic surgery, such as the BODY-Q, were identified and recorded. Studies were grouped according to the surgical technique employed and primary clinical outcomes. A qualitative analysis was performed, with studies categorized as positive (+) if they demonstrated consistent waist reduction, low complication rates, and high esthetic satisfaction; neutral (0) if results were inconclusive, inconsistent, or limited by methodological shortcomings; and negative (—) if outcomes were unsatisfactory.

The design of each study guided the methodological quality assessment. Evaluation of observational studies followed the Newcastle-Ottawa Scale (NOS),⁸ while case series analysis adhered to the adapted criteria proposed by Murad et al.⁹

The final synthesis was narrative due to the heterogeneity in study designs, populations, surgical interventions, and assessment tools, with no meta-analysis. Study screening and selection adhered to the PRISMA framework (►Fig. 1). ►Table 1 outlines the quality classification of included studies based on the NOS and Murad recommendations.

Fig. 1 - Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart describing the study selection process.

Fig. 1 - Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart describing the study selection process.

Table 1 - Methodological assessment using the Newcastle-Ottawa Scale and Murad recommendations

► Tables 2–3 present the extracted data in an organized manner for descriptive analysis and qualitative synthesis, detailing study characteristics and categorizing key clinical outcomes.

Table 2 -

Table 3 - Qualitative synthesis of the efficacy, safety, and feasibility of esthetic costal remodeling techniques.

As it represents a descriptive review with narrative synthesis and no preplanned meta-analysis, it does not meet the International Prospective Register of Systematic Reviews (PROSPERO)’s prioritization criteria; therefore, we did not register our study in this platform.

Results

The systematic search identified a total of 163 articles across the 3 electronic databases consulted: PubMed/ MEDLINE (109), LILACS (31), and Cochrane Library (23). After removing 16 duplicates, 147 unique records remained for title and abstract screening. From these papers, we excluded 122 studies as they did not meet the eligibility criteria. We analyzed 25 full-text articles and excluded 14 for various reasons, including the absence of clinical data, a sample size smaller than 5 patients, or the exclusive use of reconstructive techniques. Ultimately, 11 studies met the inclusion criteria and comprised the final sample of this systematic review. ►Table 2 presents a synthesis of the included studies, and ►Fig. 1 shows the PRISMA flowchart.

Three studies evaluated the RibXcar technique (ultrasound-guided monocortical fracture repair), with sample sizes of 30, 100, and 220 patients. In the largest study (n = 220), the documented waist reduction ranged from 6 to 11 cm. These studies reported two minor burns and high esthetic satisfaction. However, satisfaction reports were qualitative, with no objective numerical scale.¹⁰ An additional study assessed the intraoperative “clack” marker and demonstrated that only ultrasound confirmed monocortical fractures in 100% of cases, emphasizing the need for realtime imaging.¹¹

Although the largest study (n = 220) reported a measurable reduction, the absence of a control group and potential confounding from concomitant procedures limit the isolated interpretation of the effect.¹² A similar approach, the UUAIST technique (n = 131), documented a reduction of up to 8 cm, with satisfaction exceeding 97% and 3 asymmetries recorded as postoperative events.¹³

Among structural techniques, RIBOSS resulted in reductions of up to 13 cm, the highest ones reported among the available studies. Although one case of minor dehiscence was reported with this technique, no functional follow-up was documented to assess the potential impact.¹⁴ In a retrospective series, UUAIST and RIBOSS were frequently performed in combination with high-definition liposculpture (HDL) and other interventions, hindering the ability to isolate the effect of the rib procedures.¹⁵

Within the ultrasonic intervention group, the ultrasonic ostemodeling for body contouring (ORUS) technique (n = 120) reported a wide range of reductions between preand postoperative measurements, with two cases of atelectasis documented.¹⁶ The greenstick fracture with brace technique (n = 93) documented reductions in a subgroup of 14 patients, with 1 case of non-union, but no reported functional impact.¹⁷ ►Table 4 presents a direct comparison of safety across techniques, highlighting the variable event incidence: RibXcar (two burns), ORUS (two atelectases), UUAIST (three asymmetries), RIBOSS (one dehiscence), waistline esthetic slimming by puncture and parallel approach (WASP) (one pneumothorax plus one pleural effusion), and greenstick fracture (one non-union).

Table 4 - Postoperative complications

Among other minimally invasive approaches, the WASP technique (n = 15) reduced lateralization of the costal margin, resulting in high patient satisfaction and no significant complications. Complete rib resection (n = 104) was associated with 2 intraoperative pneumothoraces. However, the lack of reports on objective waist circumference measurements limits the assessment of efficacy.¹⁸

Although 1 series (n = 5) documented a 7.7% reduction in WHR, the small sample size limits the interpretability of this finding.¹⁹

In summary, reported reductions across techniques ranged from 6 to 13 cm, with the highest reductions having been reported following RIBOSS. However, the absence of control groups, methodological heterogeneity, and lack of standardized functional evaluation limit the ability to draw definitive conclusions.

Qualitative synthesis of included studies

The comparative synthesis highlights that RIBOSS achieved the greatest reductions (up to 13 cm), while minimally invasive techniques showed smaller reductions (6–8 cm). Respiratory events were most frequent with the WASP technique (one pneumothorax and one pleural effusion), whereas UUAIST presented the highest number of asymmetries (three cases). Most studies reported high patient satisfaction; however, few employed validated instruments (e.g., BODY-Q), and no study performed objective long-term functional assessments.

Overall study classification Among the 11 studies evaluated, 9 (81.8%) received a positive classification^10–17,20 by demonstrating favorable outcomes in terms of safety, technical feasibility, and patient satisfaction. Two studies (18.2%) were classified as neutral,^18,19 and no study received a negative classification, suggesting an initially favorable outlook for esthetic rib remodeling, albeit limited by methodological weaknesses.

Patient safety and satisfaction

All positive studies reported high safety, with no severe complications,^10,12,20 only documenting minor events, such as one case of mild dehiscence,¹⁴ two cases of mild atelectasis,¹⁶ and one seroma.¹⁵ A single case of non-union occurred in the brace-assisted technique, without reported functional impact.¹⁷ Patient satisfaction was high in 100% of the studies with a positive classification.

Studies with a neutral classification reported two mild pneumothoraces¹⁸ in association with complete rib resection. One study reported high satisfaction in terms of WHR reduction.¹⁹

Technical feasibility and esthetic appearance

Most studies (n = 9) reported high technical feasibility, describing the methods as safe, reproducible, easy to perform, or minimally invasive.^{10–16,19,20} A single study described the high anatomical complexity in resecting the 11^th and 12^th ribs.¹⁸

Regarding esthetic appearance, all positive studies reported objective reductions in waist circumference or clinically and esthetically significant measurements. Results from neutral studies were more variable or subjective.

Recovery and assessment methods

For positive studies, recovery time was short and complication-free.^10,13,17,20 Two other studies¹⁴,¹⁶ indicated the need for longer follow-up due to plate implantation or ultrasound use. After complete resection, improvement was visible after 40 days, with no reports of objective measurements.¹⁸ Most studies (n = 6) used objective assessments (including circumference and standardized imaging).^10–16

Methodological quality and gaps

Methodological quality was high for seven studies,^{10–13,16,17} moderate for three,^14,15,20 and partial for one study.¹

The main identified gaps included the lack of a control group,^{10,15–17,20} short follow-up times (in most studies), and the absence of standardized functional assessments.

► Table 5 summarizes the main anthropometric outcomes of waist circumference and WHR from the 11 studies. When available, we included measures of dispersion (standard deviation and interquartile ranges) and reduction ranges; studies not presenting numerical data were referred to as not reported (NR).

Table 5 - Anthropometric results (waist circumference)

Discussion

The current review shows that, although esthetic rib remodeling has gained popularity as a body-contouring alternative, the available scientific evidence remains scarce and methodologically weak. Most studies had observational designs, primarily as case series, which lacked control groups and included small sample sizes. These limitations hinder definitive conclusions about the long-term (i.e., over 12 months) efficacy and safety.^1,2 Interpretation of findings is further complicated by the heterogeneity of techniques—RibXcar, UUAIST, RIBOSS, ORUS, WASP, greenstick fracture, and floating rib resection—with variable short-term results and non-standardized outcomes.^1,2,21

Observed effectiveness is mainly concentrated in the short term (fewer than 6 months). Documented reductions in abdominal circumference ranged from 6 to 13 cm, with the greatest decrease associated with the RIBOSS technique.²¹ When assessed, WHR showed a mean reduction of 7.7%; however, this outcome was measured in only one study.¹ A major limitation is the lack of objective functional assessments, such as spirometry, chronic pain evaluation, and thoracic mobility, which represents a critical gap. This is particularly relevant given that other procedures involving rib manipulation have measurable respiratory effects, and remodeling techniques may involve osteotomy and resection.^22–25

Although safety seems acceptable in the short term, this assumption relies on fragmented and heterogeneous data. Reported adverse events included the following: two burns with RibXcar; three asymmetries with UUAIST; one wound dehiscence with RIBOSS; two cases of atelectasis with ORUS; one pneumothorax and one pleural effusion with WASP; no complications in the greenstick fracture series; and 2 intraoperative pneumothoraces in the 11th to 12th rib resection technique.^1,2,21 In several publications, information on complications was insufficient or absent, preventing accurate estimation of incidence rates and meaningful risk-benefit comparisons. ►Table 6 summarizes the adverse events reported for each technique as extracted from the included studies.

Table 6 - Complications observed in the included studies

The absence of psychosocial assessment represents another important limitation. Although validated instruments, such as BODY-Q (measuring satisfaction, self-image, and quality-of-life impact), are available, none of the included studies applied structured psychometric scales to evaluate the actual psychological benefit in healthy patients undergoing esthetic rib remodeling.²⁶ Therefore, it is not possible to determine whether perceived esthetic outcomes correspond to emotional improvement or merely reflect responses to social expectations.

From a bioethical perspective, rib remodeling is an irreversible procedure occasionally performed in healthy subjects. The literature on ethics in esthetic surgery highlights potential vulnerabilities in patient autonomy, influenced by sociocultural factors, particularly in procedures aimed at modifying the body to conform to esthetic ideals.^27–29 Additionally, the absence of formal Brazilian or international guidelines on indications, techniques, or follow-up creates ambiguity, placing the responsibility of clinical judgment and patient protection solely on the surgeon.^27–29

From a Brazilian perspective, plastic surgery plays a prominent international role, including as a destination for medical tourism.³⁰ However, the lack of procedural regulation by the Brazilian Medicine Board (Conselho Federal de Medicina, CFM, in Portuguese) and Brazilian Society of Plastic Surgery (Sociedade Brasileira de Cirurgia Plástica, SBCP, in Portuguese) allows its performance outside accredited settings, which may increase the risk of complications and compromise the institutional reputation of the specialty.³¹ The literature further suggests that Brazil has a strategic opportunity to lead the development of the first global ethical and technical guidelines for esthetic rib remodeling, standardizing indications, professional qualifications, and perioperative safety.^30,31

In summary, rib remodeling shows immediate esthetic benefits; however, these advantages are backed by weak scientific evidence due to a lack of functional follow-up, psychosocial assessment, limited technical standardization, and a significant regulatory gap. Progress in this field depends on the development of prospective studies, objective functional assessment, the use of psychometric instruments, the establishment of multicenter registries, and the formulation of ethical and regulatory frameworks—ideally led by Brazilian plastic surgery.

Conclusion

The available esthetic rib remodeling techniques demonstrate satisfactory short-term outcomes, with objective reductions in circumference and high patient satisfaction. Nevertheless, the absence of controlled studies, standardized functional assessment, and long-term follow-up precludes definitive conclusions regarding safety, durability, and optimal indications of these procedures.