Outcomes of Trauma Patients with Flail Chest and Surgical Rib Stabilization

Chest injury is the second most common unintentional injury occurring in 10-15% of all trauma patients. As a result, rib fractures are associated with significant morbidity and mortality specifically related to underlying cardiac and pulmonary injuries. ¹ Historically, management of these rib fractures has focused on pain control, positive pressure ventilation, pulmonary hygiene, and physiotherapy.^1,2,3 As early as 2014, 99% of patients with flail chest were being treated conservatively. ⁴ In recent years, more aggressive pain and respiratory management approaches have been proposed including intercostal nerve blocks and surgical stabilization of rib fractures (SSRF). ¹ Surgical stabilization of rib fractures has been associated with significant improvement in outcomes such as Intensive Care Unit Length of Stay (ICU LOS), pneumonia rates, and need for tracheostomies. ²

Aside from flail chest, our institution performs rib fixation (MatrixRIB® Fixation System, DePuy Synthes, West Chester, PA) for bicortical displacement, intubated patients with rib fractures, and non-intubated patients when their spirometry is less than 33% of predicted.

The goal of this project was to describe the current treatment practices at our Level 1 trauma center, identify which patients benefit from each treatment strategy, and compare the results of each management strategy. We hypothesized that SSRF would be consistent with other studies in the treatment of flail chest. We also expected to see improved surgical outcomes in those who required intubation. Further research is necessary to ascertain which patient populations, injury characteristics, and clinical presentation are best suited for surgical fixation.

This study was reviewed and approved by the Institutional Review Board of Eastern Virginia Medical School IRB. Trauma patients presenting to our Level 1 trauma center with a rib fracture between January 1, 2014 and June 22, 2020 were retrospectively reviewed.

Stata 16 SE software was used throughout the analysis. Categorical variables were summarized by percentages and frequencies. Univariable analysis required different statistical analysis. For categorical variables, chi-squared test and Fisher’s exact test were used. When data were found to be normally distributed, T-test was performed for independent samples.

A total of 1429 patients were reviewed. Their mean age was 55.5 years, of whom two-thirds were males. The most common mechanism of injury was by motor vehicle accident (58.6%) followed by falls (32.6%). Out of the 1429 patients, 43 (3.1%) were suffering from flail chest. Surgical stabilization of rib fractures was pursued in 27 of all patients (1.9%). Of the 27 patients who underwent SSRF, the mean Injury Severity Score (ISS) was 20.2 and the mean Glasgow Coma Scale (GCS) was 13.9. The average hospital length of stay was 15 days, the mean ICU stay was 5.3, and the mean ventilator duration was 3.4 days. When comparing these outcomes with the non-surgical group, the differences were not significant. The prevalence of pneumonia in the rib fixation group and the conservative management group was both 3.9%. Within the rib fixation group, the mortality rate within 30 days was 0% compared to 4 (.3%) among the conservative management group (P-value = .08). There were zero readmissions within 30 days among patients receiving rib fixation compared to 88 (6.3%) readmissions in those treated non-surgically (P-value = .17). Approximately half of the readmissions were directly related to their thoracic trauma including complications such as pleural effusions, pneumonia, and rib pain. There were no surgical site infections in any surgically managed patient. Flail chest was observed in 43 (3.1%) patients. Their mean age was 57.5 years old and 6.7% were males.

Out of the 43 patients who suffered a flail chest, only 16 (37.2%) received rib fixation. The 27 patients with flail chest who did not receive rib fixation were typically elderly, had contraindicating comorbidities, or another life-threatening injury that precluded surgery. In the SSRF group, the mean age was 50 years, mean ISS was 21.5, and the mean GCS was 13.9. These values in the non-surgical group were 58, 25.6, and 12.1, respectively. Hospital length of stay was similar between the 2 groups (18.3 vs 18.1 days). Mean ICU length of stays were 5.9 and 7.5 days (P-value = .522). Mean ventilation duration in the surgical group was 3.6 compared to 9.3 days in the non-surgical group (P-value = .271). These results are summarized in Table 1.

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Table 1.

Mean Outcomes of SSRF Group vs Non-Surgically Managed Group.

	Patients with flail chest (n = 43)			Intubated patients with flail chest (n = 24)
Variables (means)	Treated with SSRF (16)	Treated non-surgically (n = 27)	P-value	Treated with SSRF (8)	Treated non-surgically (n = 16)	P-value
Age	50	58	.1967	47.5	56	.3572
Injury Severity Score	21.5	25.6	.3297	24.5	29.4	.4678
Glasgow Coma Scale	13.9	12.12	.0531	15	9.2	.0808
Hospital length of stay (days)	18.3	18.1	.9850	18.5	25.9	1.0000
ICU length of stay (days)	5.9	7.4	.5220	8.5	11.9	.5515
Ventilator duration (days)	3.6	9.3	.2708	5.5	15.7	.3166

Of the 43 patients with flail chest, 24 (55.8%) were intubated. The mean age of those intubated is 52.8 years old. Two-thirds were male. Of the 24 patients who were intubated, two-thirds were managed non-surgically. For those 16 patients, the median age was 56 years compared to a median of 54 years in the SSRF group which was significantly different (P-value = .052). The mean ISS and GCS for the patients who were intubated and received rib fixation among flail chest patients were 24.5 and 15, respectively. In the non-surgical group, the mean ISS and GCS were 29.4 and 9.2, respectively. When we compared SSRF to non-surgical management in the intubated group, we saw decreases in hospital length of stay, ICU length of stay, and ventilator duration. The hospital LOS within the SSRF group was 18.5 compared to 25.9 days in the non-surgical group (P-value = 1.000). The ICU LOS within the SSRF group was 8.5 compared to 11.9 days in the non-surgical group (P-value = .552). The ventilator duration within the SSRF group was 5.5 compared to 15.7 days in the non-surgical group (P-value = .317). These results are illustrated in Table 1. In the SSRF group, there were zero deaths and readmissions compared to a mortality rate of 25% and readmission rate of 18.8% in the non-operative group. 75% of mortalities were secondary to multi-system trauma and 1 case was a result of acute respiratory distress syndrome. One of the readmissions was related to chest tightness and shortness of breath.

Nineteen patients with flail chest did not require intubation. Of these patients, 42.1% received rib fixation. For those 8 patients, the mean age is 57.5 years and the median ISS and GCS were 17.5 and 14.9, respectively. For patients with flail chest that did not require intubation, age, ISS, and GCS were 65.8, 20, and 14.7, respectively. These were not found to be significantly different between the 2 groups (P-value .252, .702, and .630 for age, ISS, and GCS, respectively. In the SSRF group, patients with flail chest not requiring intubation saw a mean hospital length of stay of 10.6 compared to 6.8 in the non-surgical group (P-value .068). Mean ICU length of stay was 2.1 days in both groups. Readmission rates in the SSRF group were 0% compared to 18.2% in the non-surgical group. Readmissions were a result of shortness of breath and thoracic or pelvic ecchymosis.

Surgical stabilization of rib fractures has shown success in managing flail chest, but it is worth noting that most patients with rib fractures do not require rib plating and not everyone with flail chest requires surgery. The data showed a downward trend in ICU length of stay and ventilator duration seen in our flail chest population that were treated with SSRF. A similar trend was seen in flail chest who required intubation without an increase in mortality and readmission. Naturally, there are limitations to our study. While our overall sample size was quite large, the low incidence of flail chest led to a small number of operations within this larger study population. This problem was exacerbated as we attempted to provide analysis of our intubated population. Rib fixation is a safe procedure resulting in minimal complications and has shown success in managing flail chest. There may be additional benefits in patients requiring intubation and mechanical ventilation. Additional research is warranted in these specific patient populations and multi-centered trials may be required to reach the necessary statistical power. In terms of our own institution, we believe that this procedure provides better outcomes to many of our patients.