|Year : 2022 | Volume
| Issue : 1 | Page : 4-9
Postoperative outcomes following surgical stabilization of rib fractures stratified by 5-factor modified frailty index
Nirvana Saraswat, Nicole Werwie, Jin Wu, Danielle Hery, Emily Saunders, Hannah Bundy, John O Elliott, Brent Goslin, William DeVoe
Department of Trauma Surgery, OhioHealth Riverside Methodist Hospital, Columbus, Ohio, USA
|Date of Submission||03-Jan-2022|
|Date of Acceptance||04-Jan-2022|
|Date of Web Publication||30-Dec-2022|
OhioHealth Riverside Methodist Hospital, 3535 Olentangy River Road, Columbus, Ohio 43214
Source of Support: None, Conflict of Interest: None
Objectives: Surgical stabilization of rib fractures (SSRF) improves outcomes in patients with flail chest and displaced fractures with impaired pulmonary function. Elderly and frail patients with such injuries are at risk for significant morbidity and may benefit from SSRF. The 5-factor modified frailty index (mFI-5) is a validated predictor of postoperative outcomes. The purpose of this study is to evaluate the relationship between frailty and outcomes following SSRF at a tertiary care trauma center.
Methods: A retrospective review of patients undergoing SSRF from 2015 to 2019. Patients over 18 years old with two or more displaced fractures were included in the study. Exclusion criteria were isolated fracture, traumatic brain injury, and pulmonary contusion. Frail patients were defined by an mFI-5 score 2 or greater. Chi-square analysis, Fischer's exact test, and Student's t-test were used for comparative analysis as appropriate. P < 0.05 was considered statistically significant.
Results: One hundred and fifty-four patients met inclusion criteria. Forty-eight patients were designated frail and 106 nonfrail. The mean number of fractures was similar between frail and nonfrail groups (7.0 vs. 7.3, P = 0.685). Injury Severity Score was lower in the frail group (14.5 vs. 17.8, P = 0.02). Inpatient mortality (P = 0.312), rates of pneumonia, end-organ dysfunction, and surgical site infections were similar (P > 0.05). Intensive care unit admission (47.9% vs. 29.2%, P = 0.025) and tracheostomy rates (P = 0.009) were increased in the frail group. Frailty also increased the risk of prolonged mechanical ventilation >48 h on multivariate analysis.
Conclusion: Frail patients, stratified using mFI 5 score, experienced similar rates of multiple postoperative outcomes, including mortality, but had increased rates of prolonged ventilation and tracheostomy. Despite observed but expected increased morbidity in these patients, the similar complication and mortality rates suggest a role for surgical stabilization of severe rib fractures in frail patients.
Keywords: Frailty, health care, outcome assessment, rib fractures, risk adjustment
|How to cite this article:|
Saraswat N, Werwie N, Wu J, Hery D, Saunders E, Bundy H, Elliott JO, Goslin B, DeVoe W. Postoperative outcomes following surgical stabilization of rib fractures stratified by 5-factor modified frailty index. J Cardiothorac Trauma 2022;7:4-9
|How to cite this URL:|
Saraswat N, Werwie N, Wu J, Hery D, Saunders E, Bundy H, Elliott JO, Goslin B, DeVoe W. Postoperative outcomes following surgical stabilization of rib fractures stratified by 5-factor modified frailty index. J Cardiothorac Trauma [serial online] 2022 [cited 2023 Mar 27];7:4-9. Available from: https://www.jctt.org/text.asp?2022/7/1/4/366395
| Introduction|| |
Rib fractures and chest wall injury (CWI) are prevalent among patients sustaining blunt chest trauma. Rib fractures are seen in approximately 10% of blunt trauma patients with a third of these injuries associated with pulmonary complications. CWI is particularly harmful in the geriatric population. There is increased morbidity and mortality, which becomes amplified with a higher number of rib fractures. In addition to worse respiratory complications, elderly patients' (>65 years old) risk of mortality is approximately double that of younger cohorts, with published rates of 22% versus 10%.
Initial treatment of CWI includes optimization of pain control using a multimodal regimen with consideration of regional anesthetic therapy, strict pulmonary hygiene, and noninvasive or invasive ventilatory support as needed. Flail chest was one of the first CWI patterns to benefit from surgical stabilization of rib fractures (SSRF). Since then, other injury patterns have shown benefits such as multiple severely displaced fractures.,,,,, Outcomes appear to be optimized when SSRF is performed early. Originally thought to carry increased risk in the geriatric population, surgical stabilization has been shown in the literature to be advantageous for those aged over 65. Less pulmonary morbidity and improved mortality rates have been realized in several studies comparing SSRF to nonoperative treatment in the elderly., These results are supported by a recent propensity-matched analysis of the Trauma Quality Improvement Program database.
Frailty, rather than age, may more accurately reflect the elevated risk associated with both nonoperative and operative management. The 5-factor modified frailty index (mFI-5) is a validated tool that predicts postoperative outcomes similar to the original 11-factor modified frailty index., The mFI-5 variables include congestive heart failure, diabetes mellitus (DM), chronic obstructive pulmonary disease (COPD) or pneumonia history, hypertension (HTN) requiring medication, and functional status. Recently, mFI-5 has shown predictive value in trauma patients with severe frailty associated with multiple adverse outcomes.
The purpose of this study was to examine the utility of mFI-5 as applied to patients undergoing SSRF at a high-volume Level 2 trauma center with experience in CWI management. We compared postoperative outcomes in frail versus nonfrail patients, with a focus on key pulmonary complications, disposition, and mortality.
| Methods|| |
We performed an IRB-approved retrospective review of all SSRF procedures at our institution. Procedures were performed by four trauma surgeons from 2015 to 2019. Inclusion criteria were age >18 years old, more than 2 displaced fractures of ribs 3 through 10 (including flail segments), documented Injury Severity Score (ISS), and available record of mFI-5 criteria. Documented mFI-5 variables mandated a history of DM (insulin-dependent or nondependent, any type), COPD or pneumonia, HTN on active prescription medication, and functional status (independent vs. dependence in activities of daily living). Isolated (single) fractures, Glasgow Coma Scale (GCS) score <9, and severe pulmonary contusion precluding repair were considered criteria for exclusion. Frailty was defined as an mFI-5 score ≥2, and patients were therefore characterized as frail (≥2) or nonfrail (<2) [Figure 1].
Patient characteristics included gender, race, age, body mass index (BMI), ISS score, and mFI-5 score. Preoperative data collected included a total number of rib fractures, flail segment (radiographically), mechanism of trauma, preoperative tube thoracostomy, pain adjuncts, documented incentive spirometer use, intubation status and ventilator days (when applicable), coexisting illness, comorbid traumatic injuries, and outpatient use of antiplatelets or anticoagulants.
Intraoperative variables included were other major concurrent operations, thoracic exposure (traditional thoracotomy, muscle-sparing thoracotomy, and minimally invasive), use of thoracic lavage, subcutaneous or intrathoracic drain placement, video-assisted thoracoscopic surgery, hemothorax evacuation, associated diagnoses at the time of surgery, case duration (minutes), estimated blood loss, and hardware system used.
Postoperatively, we examined thoracostomy or subcutaneous drain duration, ultimate disposition, intensive care unit (ICU) length of stay (LOS), postoperative ventilation duration, and tracheostomy. Complications included recurrent hemothorax or pneumothorax requiring intervention, empyema, hardware infection, hardware malfunction, inpatient readmission within 30 days, pneumonia, surgical site infection, end-organ dysfunction, postoperative vasopressor support, and hemorrhage requiring transfusion of >2 units packed red blood cells. Inpatient mortality was tabulated after SSRF.
Data were transcribed at the time of chart review to a de-identified database. Patients were stratified into frail and nonfrail groups. Comparisons were conducted between these two groups with respect to our primary and secondary outcomes of disposition, tracheostomy rate, ICU admission, LOS, prolonged postoperative ventilation (>48 h), surgical site infection, end-organ dysfunction, pneumonia, readmission, and mortality. Dichotomization was done as appropriate. Pearson's Chi-square statistic and Fischer's exact test were used for data analysis. Independent-sample t-tests (with equal variance assumed) were used for continuous data. If Levene's test for equality of variance was significant, then independent-sample t-tests with equal variance not assumed were used. Statistical significance was established at P ≤ 0.05. All analyses were conducted with SPSS version 25- (IBM, Armonk, New York, United States).
| Results|| |
During the study, 154 patients met inclusion criteria. Of these, 48 (31.2%) were designated "frail" and 106 (68.8%) "nonfrail." The mFI-5 score was used to determine frailty, with a score of 2 or greater defined as frail. Both the groups had similar age, initial GCS, and BMI [Table 1]. As expected, the frail group was older (71.2 vs. 57.7 years, P < 0.001) and had a significantly higher prevalence of tobacco use, cardiac disease, baseline renal insufficiency, and anticoagulant or antiplatelet use preoperatively (P < 0.05). The nonfrail group had a higher presenting ISS (18 vs. 15, P = 0.02).
The mean number of total rib fractures (7.3 nonfrail vs. 7.0 frail, P = 0.685) and percentage of flail chest (54.7% nonfrail vs. 41.7% frail, P = 0.134) were similar, as were rates of pulmonary contusion. Multimodal and locoregional therapies were utilized similarly between groups. There was a trend toward a higher frequency of preoperative tube thoracostomy in the nonfrail group; however, this did not reach statistical significance (P = 0.056). Time to surgery ≤72 h was similar between groups (64.2% nonfrail vs. 72.9% frail, P = 0.284). Intraoperative characteristics were again similar between groups [Table 2].
Postoperative outcome analysis demonstrated multiple comparable endpoints between the two groups with several notable differences [Table 3]. Incidence of pneumonia, end-organ dysfunction, surgical site infection, and need for transfusion of more than 2 units of red blood cells were not statistically significantly different between cohorts (P > 0.05). Frail patients were more likely to be admitted to the ICU (47.9% vs. 29.2%, P = 0.025) and had a higher likelihood of tracheostomy placement (P = 0.009). ICU and overall LOS were similar between frail and nonfrail groups. Nonfrail patients were more likely to be discharged home compared to frail patients (P = 0.002), who were more likely to go to a care facility or rehabilitation center. Frailty was not associated with an increase in inpatient mortality (P = 0.312).
While there was a nonstatistically significant trend toward longer postoperative ventilation duration in frail patients (83 vs. 23 h, P = 0.060), frailty was found to be a risk factor on multivariate odds ratio (OR) analysis for prolonged postoperative ventilation beyond 48 h [Table 4]. Frailty also, as anticipated, was associated with elevated risk for ICU admission and lower chance of discharge to home.
|Table 4: Odds ratio (95% confidence interval) associated with frailty score|
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| Discussion|| |
Rib fractures and severe chest wall injuries are prevalent and carry an increased rate of pulmonary complications and, more importantly, rate of mortality up to 20% in the geriatric population., Evidence favoring surgical stabilization of these injuries, namely flail chest and multiple displaced fractures, is well documented with better outcomes when SSRF is performed soon after the initial insult.,,,,,, Recent work utilizing SSRF in patients 65 years and older have demonstrated benefits when compared to nonoperative treatment.,, Frailty indices such as the mFI-5, rather than other quantitative factors (such as chronologic age), may more accurately reflect the risk for adverse outcomes following surgical intervention.,,
In our retrospective review, we found that patients defined as frail, based on mFI-5 index, had favorable outcomes as compared to nonfrail patients treated at our institution. Further, our study is comparable with previously published outcomes of both operative and nonoperative management of chest wall injuries. Frail patients, as expected, were older with a statistically lower ISS, although this difference may not be relevant clinically (15 in frail patients vs. 18 in nonfrail patients). The frail cohort had higher rates of smoking, prior chest injury, cardiac disease, renal insufficiency, and anticoagulant or antiplatelet use suggesting frail patients had more chronic comorbidities than nonfrail patients. Rib fracture patterns appeared similar based on the total number of fractured ribs and percentage of flail segment, which was defined anatomically based on imaging and not by physiologic flail. Intraoperative data were largely similar between the two groups, with expected nuances in surgical technique depending on the operating surgeon. In sum, frail and nonfrail patients had similar features related to their CWI, yet frail patients had more chronic medical problems. Theoretically, this should place frail patients at higher risk of morbidity and mortality.
While the mFI-5 index has been shown to predict adverse outcomes in other studies, we found this to be partially accurate in our series. Frail patients were at risk for prolonged mechanical ventilation (>48 h) based on OR, ICU admission, and more frequent rate of tracheostomy. Two of the four frail patients requiring tracheostomy had prior tracheal stenosis before their injury. Despite this, pneumonia rates remained low, and LOS was comparable to nonfrail patients. Inpatient mortality was similar between the two groups and comparably low in frail patients undergoing SSRF. Of note, one of the inpatient mortalities in the frail group occurred within 30 days after SSRF. The patient was a 100-year-old male who suffered cardiopulmonary arrest with the return of spontaneous circulation on postoperative day 1 and ultimately expired under comfort measures on postoperative day 16.
We believe our results correlate favorably with those of Fitzgerald et al. and Kane et al., In their retrospective review, Fitzgerald et al. demonstrated decreases in pulmonary complications and a negligible mortality rate in elderly patients undergoing rib fixation as compared to traditional supportive treatment. Return to a functional state also appeared to be improved, which our study was not aimed to analyze. Kane and colleagues identified similar benefits with SSRF in patients 65 or older with severe CWI when compared to nonoperative National Trauma Data Bank (NTDB) controls. In their series, despite higher risk preoperative characteristics, geriatric patients treated with SSRF demonstrated lower pneumonia (5.1%) and mortality rates (2.3%) as compared to NTDB controls. Tracheostomy rates were 10.3%, akin to that seen in our series (8.3%). Mortality related to severe CWI in advanced age appears to be 7%–22%., Taking this information within the context of the low mortality rate identified in our current study, SSRF remains promising inappropriately chosen frail patients with traumatic chest wall injuries.
The limitations of our review are several. The sample size remains small, and there are inherent shortcomings of a retrospective study. We are cognizant of the potential for selection bias in consideration of surgical stabilization for the frail cohort. Although it is our practice to offer fixation to most frail patients without an absolute contraindication to surgery who have appropriate medical and cardiac clearance. While the mFI-5 is validated in several surgical disciplines, its application in multiply-injured trauma patients with severe chest wall injuries is not well defined. A nonoperative comparison group within our institution is currently being collected to attempt a matched comparison with the operative frail group for additional analysis. Ideally, a large prospective trial would more distinctly define the postoperative outcomes in this patient population and is an area for potential future research. Finally, future research could compare our findings, using the m-FI index, to another commonly used index such as the Charlson Comorbidity Index (CCI). The CCI uses more comorbid conditions which could add further depth to our outcomes analysis.
| Conclusion|| |
Frailty, as defined by the mFI-5, was not associated with worse mortality, higher pneumonia risk, or increased LOS in this retrospective study of patients who underwent SSRF. Frail patients tend to experience increased rates of prolonged ventilation and tracheostomy as compared to nonfrail patients following surgical stabilization of severe chest wall injuries. Accordingly, SSRF should be considered in this high-risk population.
The Institutional Review Board approved the study protocol.
The authors would like to acknowledge Kwang I Suh, MD, and John A Bach, MD, for their contributions.
Financial support and sponsorship
Riverside Methodist Hospital, Trauma Department.
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]