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Trauma Service, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, AustraliaSchool of Medicine, Griffith University, Southport, Queensland, AustraliaRoyal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia
Trauma Service, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, AustraliaSchool of Medicine, Griffith University, Southport, Queensland, AustraliaRoyal Brisbane and Women’s Hospital, Brisbane, Queensland, AustraliaSchool of Medicine, The University of Queensland, Brisbane, Queensland, Australia
Rib fractures in multitrauma patients are associated with high morbidity and mortality.
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We examined studies comparing surgical rib fixation to conservative management alone.
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Surgical rib fixation is beneficial to a range of outcomes compared to conservative management.
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This is particularly for surgery within 72 h and in patients with flail chest injuries.
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Conservative management may be more beneficial to patients over 60 y old.
Abstract
Background
Multiple rib fractures and flail chest are common in trauma patients and may result in significant morbidity and mortality. While rib fractures have historically been treated conservatively, there is increasing interest in the benefits of surgical fixation. However, strong evidence that supports surgical rib fixation and identifies the most appropriate patients for its application is currently sparse.
Methods
A systematic review and meta-analysis following PRISMA guidelines was performed to identify all peer-reviewed papers that examined surgical compared to conservative management of rib fractures. We undertook a subgroup analysis to determine the specific effects of rib fracture type, age, the timing of fixation and study design on outcomes. The primary outcomes were the length of hospital and ICU stay, and secondary outcomes included mechanical ventilation time, rates of pneumonia, and mortality.
Results
Our search identified 45 papers in the systematic review, and 40 were included in the meta-analysis. There was a statistical benefit of surgical fixation compared to conservative management of rib fractures for length of ICU stay, mechanical ventilation, mortality, pneumonia, and tracheostomy. The subgroup analysis identified surgical fixation was most favorable for patients with flail chest and those who underwent surgical fixation within 72 h. Patients over 60 y had a statistical benefit of conservative management on length of hospital stay and mechanical ventilation.
Conclusions
Surgical fixation of flail and multiple rib fractures is associated with a reduction in morbidity and mortality outcomes compared to conservative management. However, careful selection of patients is required for the appropriate application of surgical rib fixation.
Rib fractures are prevalent injuries in trauma and carry a heavy burden of disease. Increased recognition of the contribution of rib fractures to both morbidity and mortality in multitrauma patients has fostered an interest in optimizing treatment regimes. While historically, rib fractures were managed nonoperatively, emerging evidence suggests that optimal treatment of these patients may sometimes involve primary surgical fixation.
Early studies have identified benefits of surgical rib fixation across a range of outcomes, including mortality, length of mechanical ventilation, and pulmonary complications. However, evidence that identifies the most appropriate cohort of patients for surgical rib fixation is sparse.
Rib fractures account for 10% of all trauma admissions and carry a heavy burden of morbidity and mortality.
However, as this injury is often described as a marker of another injury, it may be difficult to isolate the specific effects of rib fractures on outcomes compared to the possible synergistic effects of a concomitant injury. Mortality directly associated with rib fractures typically occurs due to pulmonary complications such as ventilation-perfusion abnormality, hypoxemia, and infective sequelae resulting in sepsis. An estimated one-third of patients with rib fractures develop secondary pulmonary complications leading to significant morbidity and mortality.
Studies have identified several key risk factors associated with increased morbidity and mortality, including age, pre-existing comorbidities, higher numbers of rib fractures and patients with concomitant injuries.
The heavy burden of rib fracture-associated morbidity and mortality has recently generated interest in optimizing treatment regimes. Rib fracture management aims to restore pulmonary function and treat underlying thoracic injury to avoid respiratory complications.
Rib fracture stabilization adds another paradigm to their management. For achieving the primary goal of osteosynthesis, surgical approaches aim to restore chest wall stability and improve mechanical integrity while also utilizing conservative management options.
A multicenter, prospective, controlled clinical trial of surgical stabilization of rib fractures in patients with severe, nonflail fracture patterns (Chest Wall Injury Society NONFLAIL).
Surgical fixation was previously reserved for patients where conservative management alone had failed and in patients with severe flail chest. However, the indication for surgical fixation as a primary management option is expanding. The efficacy of surgical fixation compared to conservative management alone across a broader scope of rib fracture injury has been investigated in a small number of randomized controlled trials (RCTs) and observational studies. From these studies, several systematic reviews and meta-analyses have attempted to quantify the benefits of rib fixation compared to conservative management. Most of these meta-analyses examined patients with flail chest injuries only. All meta-analyses found some benefit of surgical rib fixation for outcomes, including length of stay in ICU and hospital,
Safety and effectiveness of surgical fixation versus non-surgical methods for the treatment of flail chest in adult populations: a systematic review and meta-analysis.
Safety and effectiveness of surgical fixation versus non-surgical methods for the treatment of flail chest in adult populations: a systematic review and meta-analysis.
However, the efficacy of surgical fixation for certain outcomes was inconsistent between meta-analyses. These conflicting results are likely due to the significant heterogeneity of currently available primary studies. Difficulties in appropriately diagnosing and scoring rib fracture severity, variability of fracture patterns, and the significant influence of patient characteristics and comorbidities on outcomes make the pooled analysis of individual studies challenging. With the pooling of disparate primary studies, the applicability of these findings in clinical practice is currently limited.
With increasing interest in the potential advantages of surgical fixation, new protocols are being established that aim to identify suitable patient cohorts for surgical fixation. However, no systematic reviews to date have attempted to stratify comparable primary studies by subgroups to determine if there is a benefit of surgical fixation for specific cohorts of patients. Consequently, there is currently limited evidence to inform decision-making regarding the appropriate selection of patients for surgical fixation.
The aim of this systematic review was, therefore, to employ multiple subgroup analyses of primary literature to identify the patient cohorts that are most appropriate for surgical fixation compared to the conservative management of rib fractures.
Methods
A review protocol and data extraction methods were established by the authors according to the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guidelines.
This review was registered with PROSPERO, an international database of prospectively registered systematic reviews (registration number: CRD42020208832).
Database searches were conducted between June and July 2021.
A systematic search strategy was developed to identify studies that compared surgical rib fixation and conservative (nonoperative, multimodal) management in flail chest or multiple rib fracture patients. An extensive search for relevant studies was completed using the following electronic databases: PubMed (via PubMed), Web of Science, EMBASE, and CINAHL (via Ebscohost). These databases were searched for relevant articles containing the keywords: (“Rib∗” OR “Chest”) AND (“Flail” OR “Fracture” OR “Segment∗”) AND (“Management” OR “Operat∗” OR “Non∗Operat∗” OR “ORIF” OR “Open Reduction Internal Fixation” OR “Fixat∗” OR “Plat∗”). Reference lists from the papers obtained via the database search were examined to identify potential papers for inclusion. Only publications in peer-reviewed journals were considered. The title and abstract of the papers identified in the electronic searches were inspected. The full text of each paper was then examined in greater detail as per the defined inclusion/exclusion criteria. All discrepancies during study selection, data extraction, and quality assessment were resolved by re-checking source papers.
Inclusion and exclusion criteria
For inclusion, studies were required to fulfill the following criteria: (a) original article, (b) quantitative observational studies, prospective studies, and RCTs, (c) injury occurring within the past 20 y (2001-2021), (d) available in the English language, (e) methodological comparison of surgical fixation and nonoperative management of rib fractures, (f) adult cohort (individuals over the age of 18). Studies were excluded if they were: (a) Case-reports, reviews, abstracts, animal studies, cadaveric studies, (b) opinions or abstracts, (c) papers that did not include a nonoperative control group, (d) papers of exclusive subgroups with confounding comorbidities (e.g., traumatic brain injury) not applicable to the general trauma population. While all attempts were made to obtain full-text articles, studies were excluded if they could not be accessed (n = 7).
Outcome measures
The primary outcome measure was the length of stay (ICU and hospital) and secondary outcome measures included: duration of mechanical ventilation, mortality, pneumonia, tracheostomy, respiratory function, pain, and adverse surgical outcomes.
Methodological quality
The methodological quality of non-RCT papers was assessed using an adapted Risk of Bias in Nonrandomized studies-I (ROBINS-I) assessment. The ROBINS-I instrument assesses the methodological quality of observational studies with two or more interventions.
This quality assessment tool was selected as it specifically stratifies bias into groups of low, moderate, serious, and critical risk of bias. For ease of assessment, serious and critical risk of bias was combined into a “high” group, and an additional “not described” group was also included. RCTs included in this systematic review were assessed using an equivalent tool, the Cochrane Risk of Bias (RoB-2).
The authors acknowledge that an overall quality assessment score assumes that each quality measure has equal weight and is not necessarily an accurate representation of a paper’s quality. However, an average of the seven assessment criteria was calculated in this paper in order to perform a sensitivity analysis of papers considered “high-risk” of bias during the meta-analyses.
Statistical analyses
We used Review Manager version 5.4 for Mac, a statistical software package designed to analyze Cochrane Collaboration systematic reviews. Where data was given as raw and matched groups, the matched sample was used for the meta-analysis. Standard deviations were estimated from the reported confidence intervals (CI), standard errors, or interquartile ranges based on Hozo et al. and Bland et al. calculations.
Where studies used the same scale for each outcome, the mean differences (MD) for continuous data were calculated. We reported the relative risk (RR) for any dichotomous outcome. The precision of the effect size was reported as 95% confidence intervals.
Heterogeneity was assessed using the I2 statistic, as the measure is independent of the number of studies in the meta-analysis, and therefore, has greater power to detect heterogeneity when the quantity of studies is small. An estimate of 50% or greater was considered as possible heterogeneity, and scores of 75%-100% indicated considerable heterogeneity. A random-effects model was used for all analyses as we could not definitely exclude interstudy variation even in the absence of statistical heterogeneity given the range of inclusion criteria and surgical fixation types across papers. A two-sided P-value <0.05 was considered significant. For any outcomes where there were at least ten studies, we tested for publication bias using Egger’s regression test. This test uses a random-effects meta-regression to examine whether there is a statistically significant relationship between effect size and study precision.
We considered a two-sided P value of <0.05 as significant to suggest the presence of a small-study effect and potential publication bias. A sensitivity analysis was attempted to assess for the robustness of the pooled estimates and included evaluation of the risk of bias, Injury Severity Score (ISS), and for those studies where standard deviation was calculated rather than provided in the paper.
Subgroup analysis
For identifying whether surgical rib fixation is most appropriate for specific cohorts of patients, subgroup analyses were undertaken, including study type (RCT, prospective and retrospective), rib fracture pattern (flail, multiple, combined), and patient characteristics, including age (>60 versus all ages), the timing of fixation (<72 h versus > 72 h), number of rib fractures (average < 6 versus > 6), average ISS score (<20, 20-30, >30) and publication date (<2015, >2015).
Results
A total of 45 papers were identified, including four RCTs, five prospective (not randomized) studies, and 35 retrospective studies (Fig. 1). Of these studies, 40 were included in the meta-analysis (Appendix Table 1). Two studies included patients from the same cohort, and data was only included from one of the studies, where both reported on a particular outcome.
A total of 10,892 patients were included in the pooled analysis involving 2960 patients from the surgical fixation group and 7932 patients from the conservative group. A variety of surgical fixation types were used, such as Kirschner-wires, intramedullary nails, and plates (titanium, titanium-nickel, and polymer) with screws (locking, cancellous and bicortical), rib clips, or sutures. A summary of the fixation device utilized by each study is outlined in Appendix Table 2. Several studies did not indicate the rib fixation type. Nonoperative management primarily consisted of analgesia and ventilatory support, although few studies described their conservative treatment regimen in detail.
The weighted average age of surgical fixation patients across all studies was 54.7 y and for conservatively managed patients was 53.3 y (Appendix Table 1). Four studies examined patients over 60-year old and had an average age of surgically managed patients of 70 y and conservatively managed patients of 74.3 y. Across all studies, three out of four patients were males in both surgical and conservative groups. The weighted average number of ribs fractured was 6.6 for the surgical group and 7.4 for the conservative group.
Quality assessment
Ten reviews were rated overall as low risk of bias, 26 as moderate, and four as high (Table 1). Several studies did not supply sufficient information to assess bias across categories. The sensitivity analysis adjusting for study quality found no significant differences in outcomes when a high risk of biased studies was removed.
Geriatric (G60) trauma patients with severe rib fractures: is muscle sparing minimally invasive thoracotomy rib fixation safe and does it improve post-operative pulmonary function?.
Surgical management of multiple rib fractures reduces the hospital length of stay and the mortality rate in major trauma patients: a comparative study in a UK major trauma center.
A multicenter, prospective, controlled clinical trial of surgical stabilization of rib fractures in patients with severe, nonflail fracture patterns (Chest Wall Injury Society NONFLAIL).
Effectiveness of surgical rib fixation on prolonged mechanical ventilation in patients with traumatic rib fractures: a propensity score-matched analysis.
Twenty-nine studies (n = 8671) reported on length of ICU stay (ILOS). Surgical rib fixation resulted in a statistically significant reduction of ILOS compared to conservative management (MD: –1.29 (–2.29, –0.29), P ≤ 0.03, I2 = 95%) (Table 2). Surgical fixation reduced ILOS in studies that included patients of any age, but in studies exclusively examining patients over 60 y old, there was a nonsignificant trend toward the benefit of conservative management (Table 3). When stratified by rib fracture pattern, ILOS had a statistically significant benefit in the surgical fixation group for flail chest although not for multiple fractures alone or combined injury (flail and multiple) (Fig. 2). When stratified by study type, there was only the benefit of surgical fixation on ILOS in prospective studies and the early surgical group (<72 h).
Table 2Meta-analysis for pooled results of all available primary studies for outcomes.
Length of hospital stay (HLOS) was reported in 27 studies (n = 7138). For all included studies, there was no statistically significant reduction in HLOS in the surgical fixation group compared to nonoperative treatment (MD: –0.36 (–2.50, 1.79), P = 0.03, I2 = 95%). In studies of patients over 60 y old, the subgroup analysis of four studies greatly favored conservative management with a mean difference of 6.20 (95% CI: 5.04-7.36, P ≤ 0.001, I2 = 60%) (Fig. 3).
Fig. 3Subgroup analysis of age on length of hospital stay comparing surgical and conservative management.
Twenty-five studies (n = 5568) reported on days of mechanical ventilation (MV), which showed a statistical benefit of surgical fixation compared to conservative management across all studies (MD: –1.67 (–2.61, –0.72), P ≤ 0.03, I2 = 92%). Surgical fixation demonstrated statistically significant benefit to MV in patients across all age groups. In comparison, conservative management was associated with a shorter MV in patients over 60 y, although only two studies were available for the pooled analysis (Table 3). There was the benefit of surgical fixation for flail chest but not for multiple rib fractures or combined studies (Fig. 4). Only retrospective studies demonstrated the advantage of surgical fixation, whereas prospective studies were not significant. The early surgical fixation group demonstrated a statistically significant reduction in MV compared to the late fixation group.
Fig. 4Subgroup analysis of rib fracture pattern type on length of mechanical ventilation comparing surgical and conservative management.
Mortality rates were reported in 27 studies (n = 8818), which showed overall benefit in the surgical group (OR: 0.63 (0.44, 0.03), P ≤ 0.04, I2 = 16%). This result was statistically significant for all age groups (Table 3). When stratified by rib fracture pattern, studies that examined combined rib fractures (flail and multiple) found the benefit of surgical fixation on mortality rates. However, the pooled analysis of studies examining flail or multiple rib fractures only did not have a significant benefit. Prospective studies found no significant benefit to mortality, whereas retrospective studies showed a benefit of surgical fixation.
Pneumonia
The incidence of pneumonia was reported in 25 studies (n = 5948), which showed an overall benefit of surgical fixation (OR: 0.77 (0.62-0.97), P ≤ 0.0001, I2 = 71%). Subgroup analysis identified the statistical advantage of surgical fixation on rates of pneumonia for patients of all ages but was nonsignificant in studies of patients over 60 y (Table 3). When the pooled analysis was stratified by rib fracture pattern, no group showed significant benefit. Only prospective studies identified the advantage of surgical fixation on the incidence of pneumonia. There was a statistical benefit to rates of pneumonia in the early but not the late surgical group.
Tracheostomy
Sixteen studies (n = 3886) reported on the number of patients requiring tracheostomy. Compared to conservative management, surgical fixation resulted in an overall reduction in the requirement for tracheostomy (OR: 0.63 (0.40, 0.99), P = 0.03, I2 = 75%). This benefit was identified in patient groups across all ages but not in studies exclusively examining patients over 60 y old, although only two studies were available for comparison. The subgroup analysis found only prospective studies showed statistically significant benefit of surgical fixation on mechanical. When stratified by rib fracture pattern, flail and combined rib fracture studies found no significant benefit of surgical fixation on rates of tracheostomy.
Adjusting for confounders
We undertook a subgroup analysis comparing ISS score and average rib fracture number between original studies on outcomes (Table 3). This analysis identified no major differences in outcomes for these variables between groups. There was significant variability in reporting of comorbidities and other risk factors, such as smoking status, across studies, and we were unable to conduct a sensitivity analysis to account for these confounders.
Five studies described the patient smoking status, and in the majority of these studies, there was a larger portion of patients actively smoking in the surgical group than the conservative group (Appendix Table 3). There was significant variation in the percentage of patients with underlying lung disease across seven studies and in three studies that indicated the percentage of patients with diabetes. BMI was recorded in four studies and ranged from an average of 25 to 28. Of the four studies that included only patients over 60 y old, three provided data on comorbidities. However, one study only provided a “modified comorbidities score” and did not provide a breakdown of comorbidity type (heart disease, lung disease, etc.).
Other outcome measures
Quality of life (QOL) was compared between groups in eight studies, but there were significant inconsistencies between measurement scales, and quantitative analysis could not be performed for this subjective clinical outcome.
A multicenter, prospective, controlled clinical trial of surgical stabilization of rib fractures in patients with severe, nonflail fracture patterns (Chest Wall Injury Society NONFLAIL).
found a statistically significant benefit of surgical fixation on QOL but the other papers found no benefit. Pain was also measured in 13 studies using a range of scoring systems, including the Visual Analog Scale (VAS), numerical pain score, and questionnaires. Studies typically favored surgical fixation for improvements in pain scores compared to conservative management,
A multicenter, prospective, controlled clinical trial of surgical stabilization of rib fractures in patients with severe, nonflail fracture patterns (Chest Wall Injury Society NONFLAIL).
The timeframe of data collection for follow-up of quality of life and pain scores varied across studies.
No significant differences between groups were found for any outcomes when subgroup analyses were conducted for the average number of rib fractures, ISS score, plating device, and publication date.
Heterogeneity of studies
There was significant statistical heterogeneity between studies included in the meta-analysis and subgroup analyses. Based on the I2 analysis, only the pooled analysis of mortality had a low degree of heterogeneity. All other outcomes are likely to have considerable heterogeneity across studies. Egger’s regression test identified possible publication bias across studies for mortality and tracheostomy outcomes (Table 4 and Appendix Fig. 1). Interpretation of results from these outcomes were therefore considered judiciously.
Table 4Egger’s Regression for publication bias.
Outcomes
2-Tailed P value (intercept)
Standard error
95% CI
Interpretation
ICU LOS
0.435
0.975
–1.435, 0.639
No evidence of publication bias
Hospital LOS
0.341
0.153
–0.501, 1.39
No evidence of publication bias
Mechanical ventilation
0.11
0.003
–0.126, 1.151
No evidence of publication bias
Mortality
0.018
0.102
–3.021, –0.301
Possible publication bias
Pneumonia
0.065
0.003
–0.051, 1.614
No evidence of publication bias
Tracheostomy
0.009
0.001
0.375, 2.143
Possible publication bias
Assuming asymmetry as significant if P value = <0.05.
In this systematic review of 45 studies, including a meta-analysis of 40 studies, surgical fixation of patients with rib fractures resulted in a shorter ILOS, MV days, rates of mortality, pneumonia, and requirement for tracheostomy. Subgroup analyses of the pooled studies suggest that surgical fixation may only be beneficial when undertaken within 72 h and in patients with flail chest. Furthermore, our study indicates that surgical rib fixation may not be beneficial for patients over 60 y of age. Our findings reaffirm the important role of surgical fixation as an adjunct to conservative management.
The pooled results of our meta-analysis concur with previous reviews. These studies have consistently demonstrated the benefit of surgical fixation for a range of outcomes, specifically ILOS, mechanical ventilation days, and rates of pulmonary complications.
Safety and effectiveness of surgical fixation versus non-surgical methods for the treatment of flail chest in adult populations: a systematic review and meta-analysis.
However, each review reports limitations of the validity of their results due to quantitative pooling of heterogeneous primary studies. Our systematic review identified significant discrepancies in the eligibility of patients for surgical management across studies regarding patient age, ISS score, concomitant injury, and definitions of rib fractures. This heterogeneity may be explained by an absence of a universal protocol for appropriate selection of patients and a lack of standardized rib fracture terminology, including definitions of flail chest, multiple rib fractures, and the degree of fracture displacement. Notably, there are efforts being made by organizations, such as the AO Thoracic Expert Group and Chest Wall Injury Society, to establish standardized rib fracture nomenclature and algorithms for appropriate patient selection for surgical management.
However, these are yet to be widely promulgated. To our knowledge, this is the first meta-analysis that has attempted to identify the specific patient cohorts that are most appropriate for surgical fixation of rib fractures compared to those that should continue to be managed conservatively.
Injury pattern type
Our study identifies a reduction in ILOS and MV days for patients with flail chest who underwent surgical fixation compared to the conservatively managed group. Its benefit for multiple rib fractures is less clear. Compared to multiple rib fractures alone, flail chest injury is typically associated with greater respiratory complication, intractable pain, and long-term sequelae. Consequently, surgical fixation has until recently been reserved for flail chest injury, with previous systematic reviews consistently supporting its benefit on a range of outcomes.
Safety and effectiveness of surgical fixation versus non-surgical methods for the treatment of flail chest in adult populations: a systematic review and meta-analysis.
While the general consensus is that the majority of multiple rib fractures heal nonoperatively without complication, it is clear from the number of studies included in this review that there is increasing interest in the potential benefit of surgical fixation for multiple rib fractures. Despite this, only a small number of studies independently examined multiple rib fractures, meaning that there was likely insufficient power to adequately identify any benefit of surgical fixation. Several studies combined flail chest and multiple rib fractures in their analysis and demonstrated statistically significant benefit of surgical fixation on mortality rates but not for any other outcome. Three retrospective primary studies stratified patients by multiple rib fractures and flail chest injury with mixed outcomes. In the largest study, Xiao et al.
demonstrated the benefit of surgical fixation for flail chest on ILOS, but all outcomes were comparable with nonoperative management for the multiple rib fracture group. Qui et al.
found no benefit for either rib fracture type on outcomes.
Age
Older age has been identified as a major risk factor for rib fracture-related morbidity and mortality, where the risk of overall mortality doubles in patients over 65 y old.
Interestingly, stratification of studies by age found that patients over 60 y benefitted from conservative management for HLOS and days of MVs, while rates of mortality were lower in the surgical fixation group. Although only four retrospective studies were available for comparison, this suggests that surgical fixation may not be beneficial in the older population. We postulate that varying outcomes between age groups may be due to differences in the mechanism of injury and patient characteristics between younger and older cohorts. Typically, rib fractures are associated with a low energy mechanism of injury in elderly patients, such as fall from standing height, compared to a higher energy impact in younger patients, most commonly motor vehicle collision.
Cause of injury was underreported by included studies, meaning the impact of low compared to high energy mechanism on outcomes could not be determined in our review. Furthermore, older age is associated with higher rates of morbidity and mortality for any major surgery due to patients possessing a generally lower physiological reserve and higher burden of comorbidity.
found that patients over 65 y had a considerably higher burden of comorbidities such as respiratory disease, diabetes, and hypertension than the total population. Interestingly, a higher proportion of patients in the over 65 y group that underwent surgical fixation had comorbidities compared to the conservative group, which likely reflects selection bias in this observational study.
Timing of surgical fixation
While there is an increasing foundation of literature examining surgical fixation of rib fractures, optimal timing and surgical approaches remain rebated. Proponents of early repair (usually within 72 h) suggest that there is less tissue inflammation and callus formation within this time, which results in fewer surgical complications and improves outcomes. In comparison, others suggest that a delayed repair provides sufficient time for optimization of medical therapy prior to surgical intervention.
Our meta-analyses supports the benefit of early surgical fixation for mechanical ventilation, rates of pneumonia and tracheostomy compared to late fixation, which demonstrated no significant benefit over conservative management. Our findings concur with Pieracci et al.
who found benefit across a range of outcomes for patients undergoing earlier surgery compared to delayed intervention.
Study design
Pooled analysis of prospective and retrospective studies included in this systematic review found the benefit of surgical fixation over conservative management, yet the treatment effect on outcomes varied significantly between study designs. This is likely due to both the increased risk of bias associated with observational studies and the lack of available RCTs for comparison. While several systematic reviews have previously attempted to pool the few available RCTs, heterogeneity across patient selection and insufficient power limit the applicability of these results. Choi et al.
attempted to circumvent this by conducting a Bayesian review of RCTs and observational studies. The pooled effects from this study were comparable to outcomes from this current review, which found that surgical fixation was associated with fewer pulmonary complications and risk of mortality. Unlike our current study, Choi et al. also demonstrated the benefit of surgical fixation on hospital LOS, although the number of patients included in their surgical group was significantly smaller. While there arguably exists an empirical basis for the comparison of different methodologies, further level one studies are required to better quantify the benefits of surgical fixation.
Limitations
Despite our attempt to undertake multiple subgroup analyses, a major limitation of our review was the lack of studies available to investigate several key factors that may affect appropriate patient selection for surgical fixation. For instance, we were unable to stratify patients by fixation device, the severity of rib fracture injury and degree of rib fracture displacement, or by patient comorbidities due to insufficient data from the primary studies. Furthermore, important outcome variables such as pain, time to return to baseline function, impact on quality of life, and healthcare cost could not be assessed in the meta-analysis due to being under-reported and heterogenous in reporting measures. We were also unable to adjust for differences across studies regarding their criteria for inclusion/exclusion and based on individual definitions of flail chest and multiple rib fractures.
While we attempted to undertake a sensitivity analysis adjusting for patient characteristics, comorbidities, and injury severity (ISS score and the number of ribs fractured) our analysis was limited by several factors. A majority of studies failed to report pre-existing comorbidities and other risk factors such as smoking status and body mass index (BMI). Where these were reported (Appendix Table 3), no study performed a subgroup analysis comparing outcomes stratified by comorbidity. The effect of these potential confounders on outcomes of surgical rib fixation is therefore, still undetermined.
Conclusion
This meta-analysis of available studies supports the application of surgical rib fixation to improve morbidity and mortality outcomes in certain patient cohorts. While further delineation of criteria for appropriate selection of patients for surgical fixation is required, current evidence suggests that patients with flail chest may be best suited. Early surgery, within 72 h, also appears preferable. Conversely, older patients are more likely to benefit from conservative management. The current literature includes studies that are heterogeneous in design, patient selection, and outcome measurement. Further clarification of appropriate patient selection for surgery is necessitated for future studies through careful stratification by surgical technique, rib fracture pattern, and patient characteristics.
Author Contributions
Data were independently extracted by ES and NM. ES analyzed the data and drafted the manuscript. MM and MW provided content expertise and editing of the manuscript. The main changes to the updated manuscript were completed by ES and reviewed by MM and MW.
A multicenter, prospective, controlled clinical trial of surgical stabilization of rib fractures in patients with severe, nonflail fracture patterns (Chest Wall Injury Society NONFLAIL).
Safety and effectiveness of surgical fixation versus non-surgical methods for the treatment of flail chest in adult populations: a systematic review and meta-analysis.
Geriatric (G60) trauma patients with severe rib fractures: is muscle sparing minimally invasive thoracotomy rib fixation safe and does it improve post-operative pulmonary function?.
Surgical management of multiple rib fractures reduces the hospital length of stay and the mortality rate in major trauma patients: a comparative study in a UK major trauma center.
Effectiveness of surgical rib fixation on prolonged mechanical ventilation in patients with traumatic rib fractures: a propensity score-matched analysis.
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