a b s t r a c t

Background: Blunt traumatic diaphragmatic injury (BTDI) is an uncommon injury and one which is difficult to di- agnose. The objective of this study was to identify features associated with this injury.

Methods: This was a retrospective study based on records of 354 307 blunt Trauma victims treated between 1998 and 2013 collected by the Israeli National trauma registry.

Results: BTDI was reported in 231 (0.065%) patients. motor vehicle accidents were responsible for 84.4% of the injuries: 97 (42.0%) were reported as drivers; 54 (23.4%) were passengers; 34 (14.7%) were pedestrians hit by cars; and 10 (4.3%) were on motorcycles. There were more males than females (2.5:1) compared with blunt trau- ma patients without BTDI (p b .001). Patients with BTDI were significantly younger than blunt trauma patients without BTDI (p b .001). ISS was 9-14 in 5.2%, 16-24 in 16.9%, 25-75 in 77.9%. Urgent surgery was performed in 62% of the patients and 79.7% had surgery within 24 h of admission. Mortality was 26.8%. Over 40% of patients with BTDI had associated rib, pelvic and/or extremity injuries. Over 30% had associated spleen, liver and/or lung injuries. Nevertheless, less than 1% of patients with skeletal injuries and less than 2.5% with solid Organ injuries overall had associated BTDI. Despite hollow viscus injury being less prevalent, up to 6% of patients with this injury had associated BTDI. Conclusions: BTDI is infrequent following blunt trauma. Hollow viscus injuries were more predictive of BTDI than skeletal or Solid organ injuries.

(C) 2016

1. Background

Traumatic diaphragmatic injury is rarely diagnosed, with a reported incidence that varies greatly in different series – between 0.8% and 8% [1, 2]. However, the precise incidence of Traumatic diaphragmatic injury remains unknown. Analysis of reported cases in the National Trauma Data Bank of the United States in 2012 reveals that a minority of 33% of cases of traumatic diaphragmatic injury were caused by a blunt injury with the remaining majority caused by penetrating trauma [3]. Both the

* Corresponding author at: Division of General Surgery, Hillel Yaffe Medical Center,

P.O.B. 169, Hadera 38100, Israel.

E-mail addresses: mahamidam@yahoo.com (A. Mahamid), kobi.peleg@gmail.com (K. Peleg), adig@gertner.health.gov.il (A. Givon), alfici@hy.health.gov.il (R. Alfici), oolsha@gmail.com (O. Olsha), i_ashkenazi@yahoo.com (I. Ashkenazi).

¹ Israeli Trauma Group includes: Alfici R, Bahouth H, Bala M, Becker A, Jeroukhimov I, Karawani I, Kessel B, Klein Y, Lin G, Merin O, Mnouskin Y, Rivkind A, Shaked G, Sivak G, Soffer D, Stein M, and Weiss M.

shearing forces of high-velocity traumatic injuries and the acute in- crease of intra- abdominal pressure caused by a direct blow to the ante- rior of the torso have been postulated as possible mechanisms causing blunt traumatic diaphragmatic injury (BTDI) [4].

Various imaging modalities including chest radiographs, ultrasonog- raphy, computed tomography, and magnetic resonance imaging have been used in the diagnosis of diaphragmatic rupture [5]. Computerized tomography is the modality of choice for the detection of BTDI with a variable sensitivity and specificity of 61%-87% and 72%-100%, re- spectively [5-8]. However, the rate of initially missed diagnoses on CT has been reported to range from 12% to 63%. Failure to diagnose BTDI may have grave results, with mortality rates of 30%-60% reported in patients presenting late with intrathoracic strangulation of a herniated viscus [9,10].

Penetrating thoraco abdominal injuries mandate exclusion of dia- phragmatic injury [11,12]. However, in blunt trauma patients, BTDI can be easily missed in the absence of other indications for immediate surgery.

http://dx.doi.org/10.1016/j.ajem.2016.10.046

0735-6757/(C) 2016

A. Mahamid et al. / American Journal of Emergency Medicine 35 (2017) 214–217 215

The objective of this study was to identify patterns of injury that are associated with BTDI in order to identify trauma victims who require

Table 1

Associated injuries in 231 patients suffering from BTDI.

of the National Trauma Registry maintained by the Israel National Cen- ter for Trauma and Emergency Medicine Research, in the Gertner Insti-

(17.3-29.1)

(18.4-30.9)

additional workup to diagnose or rule out this injury.	Organ injured	Number of patients	% of BTDI patients with associated	% of patients with organ injury with	Odds Ratioa (95%CI)	P value
2. Methods	organ injury			associated BTDI
This was a retrospective cohort study of blunt trauma patients with	Ribs	121	52.4%	0.7%	22.4	b0.001
BTDI treated from 1998 to 2013. The data was obtained from the records	Pelvis	105	45.5%	0.9%	23.8	b0.001

Extremities 98 42.4% 0.1% 0.9

tute for Epidemiology and Health Policy Research. Data recorded in this registry includes patients treated in nineteen hospitals of which six are	Spleen	96	41.6%	2.4%	(0.7-1.1) 62.7 (48.1-81.6)	b0.001
level I trauma centers and thirteen are level II. Patients with BTDI were identified and compared to other pa-	Lungs	89	38.5%	0.9%	21.6 (16.5-28.2)	b0.001

0.396

tients with blunt trauma. Information collected included demo- graphic data (age, gender), clinical data (mechanism of trauma, hemodynamic instability, injury severity score, concomitant injuries, operation, and hospitalization in the ICU) and outcome (mortality). Hemodynamic instability was defined as systolic blood pressure less than 90 mmHg on admission.

Statistical analysis was performed using the SAS statistical software version 9.2 (SAS, Cary, NC). Statistical tests performed included Chi- square test and two sided Fisher’s exact probability test. Mantel Haenszel chi square test was used for trend analysis. A p-value of less than 0.05 was considered statistically significant.

Spinal

Liver	71	30.7%	2.2%	49.9	b0.001
(37.7-66.2)

Column

Brain Injury	50	21.7%	0.2%	3.0	b0.001
Small Bowel	20	8.7%	3.3%	(2.2-4.1) 56.2	b0.001
Sternum	13	5.6%	0.4%	(35.3-89.6) 6.6	b0.001
Large Bowel	12	5.2%	4.1%	(3.7-11.5) 69.0	b0.001
Stomach	10	4.3%	6.1%	(38.1-124.8) 103.3	b0.001
				(53.8-198.5)

71 30.7% 0.4% 7.8

(5.9-10.4)

b0.001

Results

The Israeli National Trauma Registry includes data on 354 307 blunt trauma victims admitted to selected Israeli hospitals between 1998 and 2013. BTDI was reported in 231 (0.065%) patients. Motor vehicle accidents including pedestrians hit by cars were responsible for 84.4% of the injuries: 97 (42.0%) were drivers; 54 (23.4%) were

passengers; 34 (14.7%) were pedestrians hit by cars; and 10 (4.3%) were motorcyclists. Males outnumbered females 2.5:1. The highest incidence was in patients aged 15-29 years old accounting for 95 (41.1%) of the patients. These were followed by 49 (21.2%) patients aged 30-44. Compared to 354 076 blunt trauma victims listed in the registry, the proportions of males, patients aged 15-29 and pa- tients aged 30-44 were higher in patients suffering from BTDI (OR 1.783 for males, p b .001; OR 2.964 for age 15-29, p b .001; OR

1.856 for age 30-44, p b .001).

One hundred eighty (77.9%) of the patients suffered from Significant injuries resulting in ISS 25-75. Thirty nine (16.9%) had ISS in the range of 16-24 and 12 (5.2%) in the range of 9-14. This large proportion of se- riously injured patients (94.8% with ISS >= 16) was associated with the need for urgent surgery in 61.9% of the patients, hospitalization in the ICU in 63.6% of the patients and an overall mortality of 26.8%. Causes of death in 62 patients reported in the registry were: uncontrolled hem- orrhage in 15 patients; severe multitrauma in 9 patients; severe head injury in 5 patients; severe cardiac injury in 5 patients; multiple organ failure in 4 patients, severe pulmonary injury in 2 patients; severe vas- cular injury in one patient; severe pelvic injury in one patient; and un- known in 20 patients.

Table 1 presents the proportion of associated injuries in patients with BTDI. The most common injuries were skeletal, lung and solid ab- dominal organs. Less common were significant head injuries and hollow viscus abdominal organs. Though over 40% of the patients with dia- phragmatic injury had associated skeletal injuries and over 30% had solid organ injuries, less than 1% and 2.5% respectively of blunt trauma patients with these injuries had associated BTDI.

The organ least injured in patients with BTDI, the stomach, proved to be the best indicator of BTDI. While only 4.3% of patients with BTDI had an associated stomach injury, 6.1% of patients with stomach injury had associated diaphragmatic injury.

^a Odds Ratio here is the ratio of the odds of BTDI occurring in patients with a specific organ injury (described in the table) to the odds of BTDI occurring in patients without this specific injury.

One hundred forty three (61.9%) patients underwent surgery for their BTDI. Fig. 1 demonstrates the timing of surgery and associated he- modynamic instability. One hundred fourteen (79.7%) patients were operated within 24 h of admission.

Discussion

The low incidence of BTDI and the difficultly in diagnosis makes it a challenging injury. Until recently, most of our knowledge concerning BTDI derived from descriptive articles with relatively small numbers of patients. Many of these include both penetrating and blunt trauma patients together.

In 2015, Fair et al. [3] reported their findings concerning 1240 pa- tients with BTDI identified in the American College of Surgeons (ACS) National Trauma Data Bank . Our findings parallel those report- ed in the American study. Both studies emphasize the rarity of BTDI (0.065% and 0.148% respectively). BTDI was found to be more prevalent in young males and was mostly caused by Motor vehicle collisions (86.2% and 63.4% respectively). In both studies the overwhelming ma- jority of the patients sustained severe injuries, and the mortality rate was high (26.8% and 19.8% respectively).

Our results concerning associated injuries were also similar to those observed by Fair et al. (see Table 2). Pulmonary and solid abdominal organ injuries were far more common than hollow viscus injuries in pa- tients with BTDI. We also found that skeletal injury was one of the most common injuries associated with BTDI, in keeping with the findings re- ported by Reiff et al. [13].

Lopez et al. [14] reported on 124 patients with diaphragmatic inju- ries treated in their institution, those with BTDI had high ISS and severe concomitant injuries with mortality rate up to 17%. They found that the BTDI itself was unlikely to be the cause of early death. Rather, these au- thors comment that the increased mortality in BTDI patients resulted from severe associated injuries. They concluded that patients with BTDI should be evaluated for associated severe life-threatening injuries, particularly in the presence of hemorrhagic shock.

216 A. Mahamid et al. / American Journal of Emergency Medicine 35 (2017) 214–217

Fig. 1. Timing of operation related to admission.

The findings of Lopez et al. concerning high ISS, associated injuries and mortality associated with BTDI are similar to those reported by Fair and those in the current study. Nevertheless, we disagree with the conclusions concerning these findings. It appears from the results of this and other studies, that most of the patients with BTDI were identi- fied following treatment of associated injuries, rather than the other way around. Most of the BTDI patients were severely injured, with asso- ciated injuries in need of urgent Operative treatment and hospitalization in the ICU. In our study, hollow viscus injuries were the best predictors of BTDI. Diagnosis of hollow viscus injuries is usually straightforward and demands surgery. We found that injuries to the lung, ribs, spleen and liver were not indicative of BTDI, despite their prevalence in these patients. Furthermore, most injuries to the spleen and liver are treated non-operatively.

Patients reported in the National Trauma Registry are those who were hospitalized for their injuries following trauma. The data do not include information concerning patients discharged from the emergen- cy department. It does not include information on patients identified late and operated for BTDI following their index hospitalization for trau- ma. Selection bias is a major limitation of our study. Since the National Trauma Registry is active in most of the public hospitals in Israel, includ- ing information on BTDI patients diagnosed late could result in a better understanding of this problem.

Most patients with blunt trauma today are treated non-operatively. Advances in imaging have diminished the role of explorative laparoto- my and laparoscopy in blunt trauma patients who are hemodynamically stable [15,16]. BTDI diagnosis remains a challenge in these patients. Ac- cording to Guth et al. diagnosis was delayed in 42% of their patients until laparotomy was performed for associated injuries [17]. In our study we found that more than half of the patients with BTDI had undergone ex- plorative surgery during the index admission. Of these, about 80% were conducted within the first 24 h. Hemodynamic instability was one of the major predictors for early surgery.

In order to advance our understanding of BTDI, we need to prospec- tively collect information on this uncommon injury in a dedicated regis- try which will include not only patients identified during their index hospitalization following trauma, but also patients who are diagnosed late. Information collected in such a way will shed light on the

Table 2

Percent of patients with associated injuries: comparison of two studies.

Organ injured	Fair et al. study (%)	Our study (%)
Spleen	44.8	41.6
Liver	39.7	30.7
Pulmonary injury	48.7	38.5
Small bowel	7.8	8.7
Large bowel	6.0	5.2
Stomach	4.5	4.3

prevalence of missed BTDI in patients not operated immediately for as- sociated injuries. It may allow us to identify risk factors and to formulate proper recommendations for workup and follow-up in patients with these risk factors.

In the meantime, given that there are no established patterns or in- dicators of BTDI, a high index of suspicion remains the best tool for BTDI diagnosis [18]. We suggest that severe blunt trauma patients should al- ways be suspected to be suffering from a hidden diaphragmatic injury, and an active process should be adopted to rule out this injury in those who have planned conservative management. In patients with no absolute indication for emergency laparotomy, high resolution CT scan should be used. Radiological suspicion of diaphragmatic injury ne- cessitates Diagnostic laparoscopy. In addition, radiological signs suspi- cious for hollow viscus injury may be at least a relative indication for diagnostic laparoscopy during which BTDI should be actively excluded.

Conclusions

In this study, based on a large trauma registry, BTDI proved to be un- common, occurring in only 0.065% of blunt trauma hospitalized patients. Motor vehicle accidents including pedestrians hit by cars was the most common mechanism accounting for 84.4% of the patients. BTDI was asso- ciated with a high ISS due to associated injuries requiring urgent surgery. Though solid organ and skeletal injuries were more common, associated hollow viscus injuries were more predictive for BTDI. Since solid organ and skeletal injures are usually treated nonoperatively, we cannot rule out missed BTDI in patients who did not have surgery. We recommend collecting information which is not limited to the index hospitalization following trauma to further define this injury.

Author Contributions

Study conception and design: All authors.

Acquisition of data: Kobi Peleg, Adi Givon, Israeli Trauma Group. Analysis and interpretation of data: Ahmad Mahamid, Itamar

Ashkenazi, Oded Olsha.

Draft of manuscript: Ahmad Mahamid.

Manuscript critical revision and final approval: All authors.

Disclosure

The authors report no conflict of interest and no sources of financial support.

The data presented has never been published in a journal in the form of article.

The abstract was presented as oral lecture in the ECTES 2016 meet- ing in Vienna, Austria.

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