Injury, Int. J. Care Injured 45 (2014) 855–858
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Increasing number of fractured ribs is not predictive of the severity of splenic injury following blunt trauma: An analysis of a National Trauma Registry database Kessel Boris a,*, Swaid Forat b, Ashkenazi Itamar c, Olsha Oded d, Peleg Kobi e, Givon Adi e, Jeroukhimov Igor f Israel Trauma Group1, Alfici Ricardo c a
Trauma Unit, Hillel Yaffe Medical Center, Hadera, Israel General Surgery Department, Bnai-Zion Medical Center, Haifa, Israel c Surgical Division, Hillel Yaffe Medical Center, Hadera, Israel d Surgery Department, Shaare Zedek Medical Center, Jerusalem, Israel e National Center for Trauma and Emergency Medicine Research, Gertner Institute for Epidemiology and Health Policy Research, Tel Hashomer, Israel f Trauma Unit, Assaf Harofeh Medical Center, Israel b
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 24 December 2013
Background: Association between rib fractures and incidence of abdominal solid organs injury is well described. However, the correlation between the number of fractured ribs and severity of splenic injury is not clear. The purpose of this study was to assess whether an increasing number of rib fractures predicts the severity of splenic injury in blunt trauma patients. Study design: A retrospective cohort study involving blunt trauma patients with concomitant splenic injuries and rib fractures, between the years 1998 and 2012, registered in the Israeli National Trauma Registry. Results: Of 321,618 patients with blunt mechanism of trauma, 57,130 had torso injuries, and of these 14,651 patients sustained rib fractures, and 3691 patients suffered from splenic injury. Concomitant splenic injury occurred in 1326 of the patients with rib fractures (9.1%), as compared to 2365 patients sustaining splenic injury without rib fractures (5.6%). The incidence of splenic injury among patients sustaining 5 or more rib fractures was significantly higher compared to patients suffering from 1 to 4 rib fractures. Among patients with splenic injury, the tendency to sustain associated rib fractures increased steadily with age. Patients with concomitant rib fractures had higher Injury Severity Score (ISS), but similar mortality rates, compared to patients with splenic injury without rib fractures. Among patients with concomitant rib fractures and splenic injury, there was no relation between the number of fractured ribs and the severity of splenic injury, neither as a whole group, nor after stratification according to the mechanism of injury. Conclusions: Although the presence of rib fractures increases the probability of splenic injury in blunt torso trauma, there is no relation between the number of fractured ribs and splenic injury severity. ß 2014 Elsevier Ltd. All rights reserved.
Keywords: Blunt abdominal trauma Rib fractures Splenic injury Mechanism of injury
Introduction Rib fractures are considered a marker of severe injury, predictive of higher mortality and higher rates of associated injuries [1]. In elderly patients, rib fractures increase the risk of in-
* Corresponding author at: Trauma Unit, Hillel Yaffe Medical Center Affiliated to Rappoport Medical School, Technion, Haifa, P.O. Box 169, Hadera 38100, Israel. Tel.: +972 4 6304407/98850439; fax: +972 4 6304545. E-mail address: [email protected] (K. Boris). 1 Israel Trauma Group includes: H. Bahouth, A. Becker, A. Hadary, M. Karawani, Y. Klein, G. Lin, O. Merin, B. Miklosh, Y. Mnouskin, A. Rivkind, G. Shaked, D. Simon, G. Sivak, D. Soffer, M. Stein and M. Weiss. 0020–1383/$ – see front matter ß 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.injury.2013.12.011
hospital mortality regardless of the presence or absence of other injuries [2]. The number of ribs broken has been found to be an independent risk factor for patient death [3]. Abdominal solid organ injuries are not uncommon in patients suffering from rib fractures following blunt trauma. Splenic injury, specifically, has been found to occur in as many as 6.3–23% of this patient population [4–6]. This high occurrence of associated splenic injury has led to the common practice of obtaining abdominal imaging for patients with multiple rib fractures. The primary aim of this study was to examine the relationship between the number of fractured ribs to the presence and severity of splenic injury following blunt trauma. The secondary aim was to assess the relationship between splenic injury and other factors,
K. Boris et al. / Injury, Int. J. Care Injured 45 (2014) 855–858
856
such as mechanism of trauma and age, within the group of patients with rib fractures.
Table 2 Presence of rib fractures by age groups of patients with splenic injury. Age (years)
No rib fractures (n = 2365)
Rib fractures (n = 1326)
Total (n = 3691)
0–14 15–29 30–44 45–59 60–74 75+
768 (89.8%) 980 (68.2%) 321 (51.8%) 184 (42%) 71 (33.3%) 41 (32%)
87 (10.2%) 457 (31.8%) 299 (48.2%) 254 (58%) 142 (66.7%) 87 (68%)
855 1437 620 438 213 128
Methods We performed a retrospective cohort study involving blunt trauma patients with concomitant splenic injuries and rib fractures, between the years 1998 and 2012. The data was obtained from the records of The Israeli National Trauma Registry (INTR) maintained by Israel’s National Centre for Trauma and Emergency Medicine Research, in the Gertner Institute for Epidemiology and Health Policy Research. This institute records information concerning trauma patients hospitalised in 19 hospitals of which six are Level I trauma centres and thirteen are Level II trauma centres. Close to its foundation in 1998, INTR included 8 trauma centres and with gradual accreditation, in 2012 it incorporated 19 trauma hospitals. Data collected in the registry include age, gender, mechanism of injury, number of fractured ribs, severity of the splenic injury, Injury Severity Score (ISS), and mortality. Whenever present, splenic injuries were classified as either minor (AAST grade I and II injuries), moderate (AAST grade III), major (AAST grade IV), or massive (AAST grade V). We compared the severity of splenic injury among patients suffering from different numbers of rib fractures. Statistical analysis was performed using GraphPad InStat1 Version 3.10 (GraphPad Software Inc., San Diego, CA). Statistical tests performed included Chi-square test for independence and two-sided Fisher’s exact probability test. To allow subgroup analysis according to mechanism of trauma, patients with laceration and massive disruption were grouped together and compared according to predefined subgroups of 1–3, 4–5 and 6 or more broken ribs. A p-value of less than 0.05 was considered statistically significant. Results The registry included 321,618 blunt trauma patients, of whom 57,130 were identified as suffering from torso injuries. Of the patients with torso injuries, 14,651 (25.6%) sustained rib fractures, and 3691 suffered from blunt splenic injury. Table 1 shows the distribution of patients with and without rib fractures and/or splenic injury. Splenic injury was associated with rib fractures in 1326 (9.1%) patients, as compared to 2365 (5.6%) patients with splenic injury but without rib fractures (p < 0.001). Table 2 shows the incidence of rib fractures in patients with splenic injury according to age group. There was a steady increase in the relative incidence of rib fractures with increasing age of the victims (p < 0.001). While only 10.2% of the 0–14 years’ age group had concomitant rib injuries, this incidence increased to more than 66% in patients aged 60 years and over. Table 3 shows the incidence of rib fractures in patients with splenic injury stratified according to the Injury Severity Score (ISS). Patients with rib fractures had a significantly higher ISS (p < 0.001). In some patients this increase in ISS was secondary to the additive value of rib fractures abbreviated injury scale only, Table 1 Distribution of patients suffering from torso blunt trauma: with and without splenic injury, with and without rib fractures.
Table 3 Presence of rib fractures by Injury Severity Score (ISS) of patients with splenic injury. ISS
No rib fractures (n = 2365)
Rib fractures (n = 1326)
Total (n = 3691)
1–8 9–14 16–24 25–75
516 523 546 780
71 (12.1%) 147 (21.9%) 307 (36%) 801 (50.7%)
587 670 853 1581
(87.9%) (78.1%) (64%) (49.3%)
while in others this was secondary to associated injuries. Whatever the cause for increased ISS, the mortality rate in those with rib fractures and those without was similar, 9.6% and 8.4% respectively (p = 0.27). The incidence of splenic injury was assessed according to the number of fractured ribs. Of the 14,651 patients with rib fractures, 2624 were excluded because they sustained an unknown number of fractured ribs (Table 4). The incidence of splenic injury was significantly higher among patients suffering from 5 or more fractured ribs, compared to patients sustaining up to 4 fractured ribs (p value < 0.0001) (see Table 5). Table 6 shows the distribution of splenic injury severity according to the number of fractured ribs and according to the mechanism of injury. Again, no differences were found in the distribution of severity of splenic injury or mechanism of injury according to the number of fractured ribs within each of the subgroups of patients. Discussion Several studies describe rib fracture as an indicator of blunt trauma severity. Both number of fractured ribs and patients age have been described as risk factor for increase in mortality and morbidity rates [7]. Higher mortality rates in patients with rib fractures mainly affects patients older than 65 years [8–10]. Nevertheless, tendency towards higher morbidity and mortality has also been described in younger patients as well [12]. An association between rib fractures and intra-abdominal solid organ injuries is well described [8]. Al-Hassani found that 28% of Table 4 Incidence of concomitant splenic injury in patients with rib fractures, according to number of fractured ribs. Number of fractured ribs
No splenic injury
Splenic injury
2210 (92.2%) 2726 (93.5%) 2386 (92.5%) 1383 (92.4%) 880 (90.7%) 559 (89.8%) 362 (88.9%) 532 (82.5%)
185 (7.7%) 188 (6.4%) 192 (7.4%) 113 (7.5%) 90 (9.2%) 63 (10.1%) 45 (11%) 113 (17.5%)
11,038
989
Patients without rib fractures
Patients with rib fractures
Total
No splenic injury Splenic injury
40,114 (94.4%) 2365 (5.6%)
13,325 (90.9%) 1326 (9.1%)
53,439 3691
1 RIB 2 RIBS 3 RIBS 4 RIBS 5 RIBS 6 RIBS 7 RIBS 8+ RIBS
Total
42,479
14,651
57,130
Total
Total 2395 2914 2578 1496 970 622 407 645 12,027
K. Boris et al. / Injury, Int. J. Care Injured 45 (2014) 855–858
857
Table 5 severity of splenic injury among patients with concomitant rib fractures. Number of fractured ribs
Severity of splenic injury Minor
Moderate
Major
Massive
Unknown
135 40.1% 88 47.6% 79 42.0% 79 41.2% 59 52.2% 39 43.3% 33 52.4% 25 55.6% 54 47.8%
83 24.6% 56 30.3% 66 35.1% 58 30.2% 24 21.2% 29 32.2% 16 25.4% 10 22.2% 24 21.2%
80 23.7% 32 17.3% 38 20.2% 49 25.5% 28 24.8% 19 21.1% 12 19.1% 7 15.6% 31 27.4%
39 11.6% 9 4.9% 5 2.7% 6 3.1% 2 1.8% 3 3.3% 2 3.2% 3 6.7% 4 3.5%
591
366
296
73
1 RIB 2 RIBS 3 RIBS 4 RIBS 5 RIBS 6 RIBS 7 RIBS 8+ RIBS
Total
Total
337 185 188 192 113 90 63 45 113
1326
In this study we identified that subgroup of victims with an unknown number of rib fractures had the highest proportion of massive spleen injury. We may assume that in this group there were the most injured patients, and identification of the fractured ribs had a low priority. In addition we may speculate, that in patients underwent emergency splenectomy with no CT (sometimes during laparotomy from another reason), there was overestimation of the splenic injury. However, the analysis of this group showed that most patients suffer from either mild or moderate severity of splenic injury rather than major and massive injury. Despite possible insight of these limitations, in the overall group of trauma victims with unknown number of the fractured ribs there was no clear correlation between the number of the ribs and the severity of spleen injury. The relationship of rib fractures and splenic injury following blunt trauma is not completely clear. A fractured rib seldom causes direct damage to spleen parenchyma. The presence of rib fractures usually reflects high injury impact, thus predicting a higher incidence of associated injuries. The presence and severity of splenic injury is thought to be related to the amount of energy impacted following blunt trauma. We observed that splenic injury was indeed higher in the presence of rib fractures as compared to blunt torso patients without rib fractures, and higher among patients with 5 or more rib fractures. However, the splenic injury severity was not correlated to the number of rib fractures. This suggests that beyond a certain energy threshold, other factors
the patients with multiple rib fractures had either liver or spleen injury [4]. When focusing on patients with spleen trauma, Lee et al. reported a 6.3% incidence of associated splenic injury in patients suffering from rib fractures [6]. Our study revealed a rate of 9.1%, significantly higher than the incidence of splenic trauma in patients without rib fractures (5.6%). In this study, rib fractures were commonly associated with splenic injury in most of the age groups, except children up to the age of 14. This may be explained by the observation that rib fractures are less frequent in children than in adults, due to higher rib flexibility [11]. Whether number of ribs fractured affects trauma morbidity and mortality is controversial. Whitson et al., reporting on 35,467 patients, concluded that outcome was not affected by the number of ribs fractured. However, they evaluated whether rib fractures worsened preexisting co-morbidities, not its effect on the severity of associated injuries [13]. On the other hand, Jones et al. [3] reporting on 98,836 patients, revealed that five and more fractured ribs was an independent cause of mortality. Our study revealed a significant association between rib fractures and splenic injury. While the incidence of splenic injury was significantly higher among patients suffering from 5 or more fractured ribs, compared to patients sustaining up to 4 fractured ribs, we did not identify any relation between the number of ribs fractured and the severity of splenic injury. No such relation was found also following subgroup analysis according to the mechanism of injury.
Table 6 Splenic injury severity according to number of fractured ribs and mechanism of injury. Number of fractured ribs
Minor MVAa
1 RIB 2 RIBS 3 RIBS 4 RIBS 5 RIBS 6 RIBS 7 RIBS 8+ RIBS Total a b
Moderate PHBCb
FALL
MVA
PHBC
Major FALL
OTHER
MVA
Massive PHBC
FALL
OTHER
46 36 40 33 25 22 17 25
10 13 9 7 6 3 5 14
27 21 21 14 3 7 2 10
5 9 9 5 5 1 1 5
31 39 39 13 13 4 7 15
8 5 8 4 5 3 2 5
11 16 10 5 8 8 0 3
6 6 1 2 3 1 1 1
19 22 32 21 12 8 4 19
4 4 6 3 3 3 1 4
5 10 8 4 4 1 0 6
4 2 3 0 0 0 2 2
7 4 4 2 1 1 1 1
1 0 1 0 1 0 0 2
1 1 1 0 0 1 1 0
0 0 0 0 1 0 1 1
244
67
105
40
161
40
61
21
137
28
38
13
21
5
5
3
Motor vehicle accidents excluding pedestrians. Pedestrians hit by car.
OTHER
PHBC
FALL
OTHER
MVA
858
K. Boris et al. / Injury, Int. J. Care Injured 45 (2014) 855–858
determine how many ribs will fracture, such as victims age, habitus, osteoporosis and other metabolic disorders. The main limitation of this study is that the registry does not provide information regarding which ribs were specifically broken, it does not differentiate between right and left hemithorax, nor does it differentiate between upper or lower ribs. Nevertheless, we assume that variability between groups in the number and location of fractured ribs, should be minimised, if not nullified, by the large sample size provided by the registry. Another study limitation was that the registry does not include data concerning the imaging modality used to define the number of ribs fractured. CT is more accurate in delineating the number of rib fractured compared to plain X-rays. Since this study focuses on patients with splenic injury we assume that most patients underwent CT. Only a minority of patients in this study were immediately operated on for haemodynamic instability. We think that this small group will not change the overall findings in this study. Summary In this study we examined the specific relation of rib fractures to splenic injury. Rib fractures are commonly used by emergency room physicians as an indicator whether to workup for associated splenic injury or not. The main findings of this study were: (1) Splenic injury occurred in 9.1% of the trauma victims with rib fractures, an incidence significantly higher than in patients with blunt torso injuries without rib fractures (5.6%). (2) The association of splenic injury and rib fractures increases with age. While only 10.2% of children 0–14 years of age showed this association, over 67% of those 60 years of age and older suffer from both rib fractures and splenic injury. (3) The incidence of splenic injury was significantly higher among patients with 5 or more fractured ribs, as compared to patients with up to 4 rib fractures.
(4) The severity of splenic injury in patients with concomitant rib fractures was not affected by the number of fractured ribs. Conflict of interest statement None declared. References [1] Ziegler DW, Agarwal NN. The morbidity and mortality of rib fractures. J Trauma 1994;37:975–9. [2] Kent R, Woods W, Bostrom O. Fatality risk and the presence of rib fractures. Ann Adv Automot Med 2008;52:73–84. [3] Jones KM, Reed RL, Luchette FA. The ribs or not the ribs: which influences mortality? Am J Surg 2011;202:598–604. [4] Al-Hassani A, Ablulrahman H, Afifi I, Almadani A, Al-Den A, Al-Kuwari A, et al. Rib fracture patterns predict thoracic chest wall and abdominal solid organ injury. Am Surg 2010;76:888–91. [5] Seongsik P. Clinical analysis for the correlation of intra-abdominal organ injury in the patients with rib fracture. Korean J Thorac Cardiovasc Surg 2012;45: 246–50. [6] Lee RB, Bass SM, Morris Jr JA, MacKenzie EJ. Three or more rib fractures as an indicator for transfer to a level I trauma center: a population based. J Trauma 1990;30:689–94. [7] Sirmali M, Tu¨ru¨t H, Topc¸u S, Gu¨lhan E, Yazici U, Kaya S, et al. A comprehensive analysis of traumatic rib fractures: morbidity, mortality and management. Eur J Cardiothorac Surg 2003;24(1):133–8. [8] Bulger EM, Arneson MA, Mock CN, Jurkovich GJ. Rib fractures in the elderly. J Trauma 2000;48(6):1040–6 [discussion 1046–7]. [9] Bergeron E, Lavoie A, Clas D, Moore L, Ratte S, Tetreault S, et al. Elderly trauma patients with rib fractures are at greater risk of death and pneumonia. J Trauma 2003;54(3):478–85. [10] Stawicki SP, Grossman MD, Hoey BA, Miller DL, Reed 3rd JF. Rib fractures in the elderly: a marker of injury severity. J Am Geriatr Soc 2004;52(5): 805–8. [11] Nakayama DK, Raminofsky ML, Rowe MI. Chest injuries in childhood. Ann Surg 1989;210:770–5. [12] Holcomb JB, McMullin NR, Kozar RA, Lygas MH, Moore FA. Morbidity from rib fractures increases after age 45. J Am Coll Surg 2003;196(4): 549–55. [13] Whitson BA, McGonigal MD, Anderson CP, Dries DJ. Increasing numbers of rib fractures do not worsen outcome: an analysis of the national trauma data bank. Am Surg 2013;79(2):140–50.
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Increasing number of fractured ribs is not predictive of the severity of splenic injury following blunt trauma: An analysis of a National Trauma Registry database Kessel Boris a,*, Swaid Forat b, Ashkenazi Itamar c, Olsha Oded d, Peleg Kobi e, Givon Adi e, Jeroukhimov Igor f Israel Trauma Group1, Alfici Ricardo c a
Trauma Unit, Hillel Yaffe Medical Center, Hadera, Israel General Surgery Department, Bnai-Zion Medical Center, Haifa, Israel c Surgical Division, Hillel Yaffe Medical Center, Hadera, Israel d Surgery Department, Shaare Zedek Medical Center, Jerusalem, Israel e National Center for Trauma and Emergency Medicine Research, Gertner Institute for Epidemiology and Health Policy Research, Tel Hashomer, Israel f Trauma Unit, Assaf Harofeh Medical Center, Israel b
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 24 December 2013
Background: Association between rib fractures and incidence of abdominal solid organs injury is well described. However, the correlation between the number of fractured ribs and severity of splenic injury is not clear. The purpose of this study was to assess whether an increasing number of rib fractures predicts the severity of splenic injury in blunt trauma patients. Study design: A retrospective cohort study involving blunt trauma patients with concomitant splenic injuries and rib fractures, between the years 1998 and 2012, registered in the Israeli National Trauma Registry. Results: Of 321,618 patients with blunt mechanism of trauma, 57,130 had torso injuries, and of these 14,651 patients sustained rib fractures, and 3691 patients suffered from splenic injury. Concomitant splenic injury occurred in 1326 of the patients with rib fractures (9.1%), as compared to 2365 patients sustaining splenic injury without rib fractures (5.6%). The incidence of splenic injury among patients sustaining 5 or more rib fractures was significantly higher compared to patients suffering from 1 to 4 rib fractures. Among patients with splenic injury, the tendency to sustain associated rib fractures increased steadily with age. Patients with concomitant rib fractures had higher Injury Severity Score (ISS), but similar mortality rates, compared to patients with splenic injury without rib fractures. Among patients with concomitant rib fractures and splenic injury, there was no relation between the number of fractured ribs and the severity of splenic injury, neither as a whole group, nor after stratification according to the mechanism of injury. Conclusions: Although the presence of rib fractures increases the probability of splenic injury in blunt torso trauma, there is no relation between the number of fractured ribs and splenic injury severity. ß 2014 Elsevier Ltd. All rights reserved.
Keywords: Blunt abdominal trauma Rib fractures Splenic injury Mechanism of injury
Introduction Rib fractures are considered a marker of severe injury, predictive of higher mortality and higher rates of associated injuries [1]. In elderly patients, rib fractures increase the risk of in-
* Corresponding author at: Trauma Unit, Hillel Yaffe Medical Center Affiliated to Rappoport Medical School, Technion, Haifa, P.O. Box 169, Hadera 38100, Israel. Tel.: +972 4 6304407/98850439; fax: +972 4 6304545. E-mail address: [email protected] (K. Boris). 1 Israel Trauma Group includes: H. Bahouth, A. Becker, A. Hadary, M. Karawani, Y. Klein, G. Lin, O. Merin, B. Miklosh, Y. Mnouskin, A. Rivkind, G. Shaked, D. Simon, G. Sivak, D. Soffer, M. Stein and M. Weiss. 0020–1383/$ – see front matter ß 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.injury.2013.12.011
hospital mortality regardless of the presence or absence of other injuries [2]. The number of ribs broken has been found to be an independent risk factor for patient death [3]. Abdominal solid organ injuries are not uncommon in patients suffering from rib fractures following blunt trauma. Splenic injury, specifically, has been found to occur in as many as 6.3–23% of this patient population [4–6]. This high occurrence of associated splenic injury has led to the common practice of obtaining abdominal imaging for patients with multiple rib fractures. The primary aim of this study was to examine the relationship between the number of fractured ribs to the presence and severity of splenic injury following blunt trauma. The secondary aim was to assess the relationship between splenic injury and other factors,
K. Boris et al. / Injury, Int. J. Care Injured 45 (2014) 855–858
856
such as mechanism of trauma and age, within the group of patients with rib fractures.
Table 2 Presence of rib fractures by age groups of patients with splenic injury. Age (years)
No rib fractures (n = 2365)
Rib fractures (n = 1326)
Total (n = 3691)
0–14 15–29 30–44 45–59 60–74 75+
768 (89.8%) 980 (68.2%) 321 (51.8%) 184 (42%) 71 (33.3%) 41 (32%)
87 (10.2%) 457 (31.8%) 299 (48.2%) 254 (58%) 142 (66.7%) 87 (68%)
855 1437 620 438 213 128
Methods We performed a retrospective cohort study involving blunt trauma patients with concomitant splenic injuries and rib fractures, between the years 1998 and 2012. The data was obtained from the records of The Israeli National Trauma Registry (INTR) maintained by Israel’s National Centre for Trauma and Emergency Medicine Research, in the Gertner Institute for Epidemiology and Health Policy Research. This institute records information concerning trauma patients hospitalised in 19 hospitals of which six are Level I trauma centres and thirteen are Level II trauma centres. Close to its foundation in 1998, INTR included 8 trauma centres and with gradual accreditation, in 2012 it incorporated 19 trauma hospitals. Data collected in the registry include age, gender, mechanism of injury, number of fractured ribs, severity of the splenic injury, Injury Severity Score (ISS), and mortality. Whenever present, splenic injuries were classified as either minor (AAST grade I and II injuries), moderate (AAST grade III), major (AAST grade IV), or massive (AAST grade V). We compared the severity of splenic injury among patients suffering from different numbers of rib fractures. Statistical analysis was performed using GraphPad InStat1 Version 3.10 (GraphPad Software Inc., San Diego, CA). Statistical tests performed included Chi-square test for independence and two-sided Fisher’s exact probability test. To allow subgroup analysis according to mechanism of trauma, patients with laceration and massive disruption were grouped together and compared according to predefined subgroups of 1–3, 4–5 and 6 or more broken ribs. A p-value of less than 0.05 was considered statistically significant. Results The registry included 321,618 blunt trauma patients, of whom 57,130 were identified as suffering from torso injuries. Of the patients with torso injuries, 14,651 (25.6%) sustained rib fractures, and 3691 suffered from blunt splenic injury. Table 1 shows the distribution of patients with and without rib fractures and/or splenic injury. Splenic injury was associated with rib fractures in 1326 (9.1%) patients, as compared to 2365 (5.6%) patients with splenic injury but without rib fractures (p < 0.001). Table 2 shows the incidence of rib fractures in patients with splenic injury according to age group. There was a steady increase in the relative incidence of rib fractures with increasing age of the victims (p < 0.001). While only 10.2% of the 0–14 years’ age group had concomitant rib injuries, this incidence increased to more than 66% in patients aged 60 years and over. Table 3 shows the incidence of rib fractures in patients with splenic injury stratified according to the Injury Severity Score (ISS). Patients with rib fractures had a significantly higher ISS (p < 0.001). In some patients this increase in ISS was secondary to the additive value of rib fractures abbreviated injury scale only, Table 1 Distribution of patients suffering from torso blunt trauma: with and without splenic injury, with and without rib fractures.
Table 3 Presence of rib fractures by Injury Severity Score (ISS) of patients with splenic injury. ISS
No rib fractures (n = 2365)
Rib fractures (n = 1326)
Total (n = 3691)
1–8 9–14 16–24 25–75
516 523 546 780
71 (12.1%) 147 (21.9%) 307 (36%) 801 (50.7%)
587 670 853 1581
(87.9%) (78.1%) (64%) (49.3%)
while in others this was secondary to associated injuries. Whatever the cause for increased ISS, the mortality rate in those with rib fractures and those without was similar, 9.6% and 8.4% respectively (p = 0.27). The incidence of splenic injury was assessed according to the number of fractured ribs. Of the 14,651 patients with rib fractures, 2624 were excluded because they sustained an unknown number of fractured ribs (Table 4). The incidence of splenic injury was significantly higher among patients suffering from 5 or more fractured ribs, compared to patients sustaining up to 4 fractured ribs (p value < 0.0001) (see Table 5). Table 6 shows the distribution of splenic injury severity according to the number of fractured ribs and according to the mechanism of injury. Again, no differences were found in the distribution of severity of splenic injury or mechanism of injury according to the number of fractured ribs within each of the subgroups of patients. Discussion Several studies describe rib fracture as an indicator of blunt trauma severity. Both number of fractured ribs and patients age have been described as risk factor for increase in mortality and morbidity rates [7]. Higher mortality rates in patients with rib fractures mainly affects patients older than 65 years [8–10]. Nevertheless, tendency towards higher morbidity and mortality has also been described in younger patients as well [12]. An association between rib fractures and intra-abdominal solid organ injuries is well described [8]. Al-Hassani found that 28% of Table 4 Incidence of concomitant splenic injury in patients with rib fractures, according to number of fractured ribs. Number of fractured ribs
No splenic injury
Splenic injury
2210 (92.2%) 2726 (93.5%) 2386 (92.5%) 1383 (92.4%) 880 (90.7%) 559 (89.8%) 362 (88.9%) 532 (82.5%)
185 (7.7%) 188 (6.4%) 192 (7.4%) 113 (7.5%) 90 (9.2%) 63 (10.1%) 45 (11%) 113 (17.5%)
11,038
989
Patients without rib fractures
Patients with rib fractures
Total
No splenic injury Splenic injury
40,114 (94.4%) 2365 (5.6%)
13,325 (90.9%) 1326 (9.1%)
53,439 3691
1 RIB 2 RIBS 3 RIBS 4 RIBS 5 RIBS 6 RIBS 7 RIBS 8+ RIBS
Total
42,479
14,651
57,130
Total
Total 2395 2914 2578 1496 970 622 407 645 12,027
K. Boris et al. / Injury, Int. J. Care Injured 45 (2014) 855–858
857
Table 5 severity of splenic injury among patients with concomitant rib fractures. Number of fractured ribs
Severity of splenic injury Minor
Moderate
Major
Massive
Unknown
135 40.1% 88 47.6% 79 42.0% 79 41.2% 59 52.2% 39 43.3% 33 52.4% 25 55.6% 54 47.8%
83 24.6% 56 30.3% 66 35.1% 58 30.2% 24 21.2% 29 32.2% 16 25.4% 10 22.2% 24 21.2%
80 23.7% 32 17.3% 38 20.2% 49 25.5% 28 24.8% 19 21.1% 12 19.1% 7 15.6% 31 27.4%
39 11.6% 9 4.9% 5 2.7% 6 3.1% 2 1.8% 3 3.3% 2 3.2% 3 6.7% 4 3.5%
591
366
296
73
1 RIB 2 RIBS 3 RIBS 4 RIBS 5 RIBS 6 RIBS 7 RIBS 8+ RIBS
Total
Total
337 185 188 192 113 90 63 45 113
1326
In this study we identified that subgroup of victims with an unknown number of rib fractures had the highest proportion of massive spleen injury. We may assume that in this group there were the most injured patients, and identification of the fractured ribs had a low priority. In addition we may speculate, that in patients underwent emergency splenectomy with no CT (sometimes during laparotomy from another reason), there was overestimation of the splenic injury. However, the analysis of this group showed that most patients suffer from either mild or moderate severity of splenic injury rather than major and massive injury. Despite possible insight of these limitations, in the overall group of trauma victims with unknown number of the fractured ribs there was no clear correlation between the number of the ribs and the severity of spleen injury. The relationship of rib fractures and splenic injury following blunt trauma is not completely clear. A fractured rib seldom causes direct damage to spleen parenchyma. The presence of rib fractures usually reflects high injury impact, thus predicting a higher incidence of associated injuries. The presence and severity of splenic injury is thought to be related to the amount of energy impacted following blunt trauma. We observed that splenic injury was indeed higher in the presence of rib fractures as compared to blunt torso patients without rib fractures, and higher among patients with 5 or more rib fractures. However, the splenic injury severity was not correlated to the number of rib fractures. This suggests that beyond a certain energy threshold, other factors
the patients with multiple rib fractures had either liver or spleen injury [4]. When focusing on patients with spleen trauma, Lee et al. reported a 6.3% incidence of associated splenic injury in patients suffering from rib fractures [6]. Our study revealed a rate of 9.1%, significantly higher than the incidence of splenic trauma in patients without rib fractures (5.6%). In this study, rib fractures were commonly associated with splenic injury in most of the age groups, except children up to the age of 14. This may be explained by the observation that rib fractures are less frequent in children than in adults, due to higher rib flexibility [11]. Whether number of ribs fractured affects trauma morbidity and mortality is controversial. Whitson et al., reporting on 35,467 patients, concluded that outcome was not affected by the number of ribs fractured. However, they evaluated whether rib fractures worsened preexisting co-morbidities, not its effect on the severity of associated injuries [13]. On the other hand, Jones et al. [3] reporting on 98,836 patients, revealed that five and more fractured ribs was an independent cause of mortality. Our study revealed a significant association between rib fractures and splenic injury. While the incidence of splenic injury was significantly higher among patients suffering from 5 or more fractured ribs, compared to patients sustaining up to 4 fractured ribs, we did not identify any relation between the number of ribs fractured and the severity of splenic injury. No such relation was found also following subgroup analysis according to the mechanism of injury.
Table 6 Splenic injury severity according to number of fractured ribs and mechanism of injury. Number of fractured ribs
Minor MVAa
1 RIB 2 RIBS 3 RIBS 4 RIBS 5 RIBS 6 RIBS 7 RIBS 8+ RIBS Total a b
Moderate PHBCb
FALL
MVA
PHBC
Major FALL
OTHER
MVA
Massive PHBC
FALL
OTHER
46 36 40 33 25 22 17 25
10 13 9 7 6 3 5 14
27 21 21 14 3 7 2 10
5 9 9 5 5 1 1 5
31 39 39 13 13 4 7 15
8 5 8 4 5 3 2 5
11 16 10 5 8 8 0 3
6 6 1 2 3 1 1 1
19 22 32 21 12 8 4 19
4 4 6 3 3 3 1 4
5 10 8 4 4 1 0 6
4 2 3 0 0 0 2 2
7 4 4 2 1 1 1 1
1 0 1 0 1 0 0 2
1 1 1 0 0 1 1 0
0 0 0 0 1 0 1 1
244
67
105
40
161
40
61
21
137
28
38
13
21
5
5
3
Motor vehicle accidents excluding pedestrians. Pedestrians hit by car.
OTHER
PHBC
FALL
OTHER
MVA
858
K. Boris et al. / Injury, Int. J. Care Injured 45 (2014) 855–858
determine how many ribs will fracture, such as victims age, habitus, osteoporosis and other metabolic disorders. The main limitation of this study is that the registry does not provide information regarding which ribs were specifically broken, it does not differentiate between right and left hemithorax, nor does it differentiate between upper or lower ribs. Nevertheless, we assume that variability between groups in the number and location of fractured ribs, should be minimised, if not nullified, by the large sample size provided by the registry. Another study limitation was that the registry does not include data concerning the imaging modality used to define the number of ribs fractured. CT is more accurate in delineating the number of rib fractured compared to plain X-rays. Since this study focuses on patients with splenic injury we assume that most patients underwent CT. Only a minority of patients in this study were immediately operated on for haemodynamic instability. We think that this small group will not change the overall findings in this study. Summary In this study we examined the specific relation of rib fractures to splenic injury. Rib fractures are commonly used by emergency room physicians as an indicator whether to workup for associated splenic injury or not. The main findings of this study were: (1) Splenic injury occurred in 9.1% of the trauma victims with rib fractures, an incidence significantly higher than in patients with blunt torso injuries without rib fractures (5.6%). (2) The association of splenic injury and rib fractures increases with age. While only 10.2% of children 0–14 years of age showed this association, over 67% of those 60 years of age and older suffer from both rib fractures and splenic injury. (3) The incidence of splenic injury was significantly higher among patients with 5 or more fractured ribs, as compared to patients with up to 4 rib fractures.
(4) The severity of splenic injury in patients with concomitant rib fractures was not affected by the number of fractured ribs. Conflict of interest statement None declared. References [1] Ziegler DW, Agarwal NN. The morbidity and mortality of rib fractures. J Trauma 1994;37:975–9. [2] Kent R, Woods W, Bostrom O. Fatality risk and the presence of rib fractures. Ann Adv Automot Med 2008;52:73–84. [3] Jones KM, Reed RL, Luchette FA. The ribs or not the ribs: which influences mortality? Am J Surg 2011;202:598–604. [4] Al-Hassani A, Ablulrahman H, Afifi I, Almadani A, Al-Den A, Al-Kuwari A, et al. Rib fracture patterns predict thoracic chest wall and abdominal solid organ injury. Am Surg 2010;76:888–91. [5] Seongsik P. Clinical analysis for the correlation of intra-abdominal organ injury in the patients with rib fracture. Korean J Thorac Cardiovasc Surg 2012;45: 246–50. [6] Lee RB, Bass SM, Morris Jr JA, MacKenzie EJ. Three or more rib fractures as an indicator for transfer to a level I trauma center: a population based. J Trauma 1990;30:689–94. [7] Sirmali M, Tu¨ru¨t H, Topc¸u S, Gu¨lhan E, Yazici U, Kaya S, et al. A comprehensive analysis of traumatic rib fractures: morbidity, mortality and management. Eur J Cardiothorac Surg 2003;24(1):133–8. [8] Bulger EM, Arneson MA, Mock CN, Jurkovich GJ. Rib fractures in the elderly. J Trauma 2000;48(6):1040–6 [discussion 1046–7]. [9] Bergeron E, Lavoie A, Clas D, Moore L, Ratte S, Tetreault S, et al. Elderly trauma patients with rib fractures are at greater risk of death and pneumonia. J Trauma 2003;54(3):478–85. [10] Stawicki SP, Grossman MD, Hoey BA, Miller DL, Reed 3rd JF. Rib fractures in the elderly: a marker of injury severity. J Am Geriatr Soc 2004;52(5): 805–8. [11] Nakayama DK, Raminofsky ML, Rowe MI. Chest injuries in childhood. Ann Surg 1989;210:770–5. [12] Holcomb JB, McMullin NR, Kozar RA, Lygas MH, Moore FA. Morbidity from rib fractures increases after age 45. J Am Coll Surg 2003;196(4): 549–55. [13] Whitson BA, McGonigal MD, Anderson CP, Dries DJ. Increasing numbers of rib fractures do not worsen outcome: an analysis of the national trauma data bank. Am Surg 2013;79(2):140–50.
