CT after emergency surgery in penetrating trauma: a seven-year experience in a level I Nordic trauma center

Abstract

Background

Patients with severe penetrating trauma may require emergency surgery on arrival, and postoperative computed tomography (CT) can reveal significant additional injuries.

Purpose

To determine the utility of postoperative CT performed within 48 h of emergency surgery after penetrating trauma.

Material and Methods

Trauma registry data were retrieved over a seven-year period at a single level 1 trauma center. All patients aged ≥17 years, admitted with penetrating injury, who underwent urgent surgery and postoperative CT imaging within 48 h, were included. Pre- and intraoperative medical records were compared to CT findings. Age, sex, Injury Severity Score (ISS), New Injury Severity Score (NISS), 30-day mortality, injury mechanism, surgical intervention, and intensive care unit length of stay were extracted.

Results

Out of 1262 patients, 38 fulfilled the study criteria (36 men [94.7%], 2 women [5.3%]; mean age = 31.5 years. Stab wound (SW) was the most common injury mechanism (26/38, 68.4%) followed by gunshot wound (GSW; 10/38, 26.3%). Patients with GSWs were more severely injured than SW victims (median NISS = 34 [range = 3–75]; for GSWs = 34; for SWs = 26; P = 0.045). Out of 38 patients, 20 (52.6%) had additional findings at postoperative CT. Six patients (15.8%) had unidentified or underestimated findings at CT that were severe enough to warrant additional surgery or angiography.

Conclusion

Postoperative CT imaging after emergency surgery in penetrating trauma is an important tool in evaluating the injury panorama. Out of 38 patients, 6 (15.8%) had findings at postoperative CT that warranted additional surgical or angiographic intervention.

Keywords

Trauma acute surgery thorax abdomen/GI vascular

Introduction

Computed tomography (CT) is a standard tool in evaluating the severely injured trauma patient (1–5). However, hemodynamically unstable trauma patients who have a clear indication for explorative surgery often undergo immediate life-saving surgery without preoperative CT imaging. Empiric postoperative CT is now increasingly used in this patient population to identify additional and unexpected injuries that might have been missed or remained hidden during surgery. So far, there is no universally accepted role for CT in the post life-saving surgery, and data of potential benefit of postoperative CT after emergency surgery are sparse yet encouraging (2,3,6,7). The aim of the present study was to determine the utility of postoperative CT performed within 48 h of emergency surgery after penetrating trauma in a single large Nordic level 1 trauma center.

Material and Methods

Approval from the local ethics committee was obtained for this retrospective study (Dnr 2017/1018-31/2, 2020-02164); due to its retrospective design, informed consent was waived. Seven-year data (2013–2019) of all patients with penetrating trauma were retrieved from the trauma database of a level 1 trauma center with a total catchment area of approximately 2.5 million people.

All patients aged 17 years and older who underwent emergency surgery and postoperative CT within 48 h were included. We excluded patients who underwent any type of preoperative CT during the initial trauma resuscitation, including transferred patients who underwent CT imaging at outside institutions.

The following parameters were extracted from the trauma registry and/or electronic medical records: Age, sex, Injury Severity Score (ISS), New Injury Severity Score (NISS), 30-day mortality, injury mechanism, surgical interventions, and length of intensive care unit stay (ICU-LOS). The CT images were collected from the local picture archiving and communication systems (PACS; SECTRA AB, Linköping, Sweden).

Postoperative CT studies from all eligible patients were identified and the reports and images reviewed by a senior resident in radiology with five years of experience (KHH). All CT scans had previously been interpreted by at least one radiology resident and a senior radiologist. Trauma-related findings in each CT study were evaluated both within and outside the surgical field. The clinical findings described preoperatively were also reviewed, as well as reports and images of radiographs taken in the trauma bay. Equivocal findings were settled by consensus readout.

All trauma-related findings at the postoperative CT studies were compared to findings described in the surgical reports. Comparisons were also made between the postoperative CT and the findings made preoperatively on clinical examination as well as on radiographs taken in the trauma bay. Any trauma-related findings that were seen at the postoperative CT but not described in the surgical report and the preoperative clinical examination or radiographs were classified as missed injuries, including both injuries within and outside the surgical field. Trauma-related findings were defined as injuries or foreign objects (e.g. bullet fragments) that were directly related to the trauma. Malpositioned tubes (e.g. chest tubes or endotracheal tubes), atelectasis and aspiration were not classified as trauma-related findings. The medical records were then reviewed to determine if any major changes in management occurred due to previously unknown findings on the CT scan. Major changes in management were defined as reoperations and angiographic interventions.

Wilcoxon test for independent samples, chi-square test, and Fisher's exact test were used to calculate the difference between patients with gunshot wound (GSW) and stab wounds (SW). Statistical analyses were done using a commercial software package SAS/STAT v.9.4 (SAS Institute Inc., Cary, NC, USA).

Results

During the seven-year study period, a total of 1262 patients were admitted to the trauma center after penetrating trauma: 948 (75%) for SW; 284 (23%) for GSW; and 30 (2%) for other types of penetrating trauma.

A total of 38 patients (38/1262, 3.0%; 36 men [94.7%], 2 women [5.3%]; mean age = 31.5 years; age range = 17–73 years) fulfilled the study entry criteria. A total of 26 (68.4%) patients were admitted for SWs and 10 (26.3%) for GSWs. Two patients (5.3%) were admitted for penetrating injuries other than GSWs and SWs. One of these suffered a combined penetrating and blunt injury resulting from landing on a picket fence after a 10-m fall, penetrating the patients thoracic cage as well as the abdomen/pelvis. The other patient classified in the “other” type of injury group was involved in an accident with a plough that penetrated the patient's flank.

The median ISS score was 21 (range = 1–75) and median NISS score was 34 (range = 3–75) (Table 1). Patients who suffered from GSWs tended to have higher ISS scores than those admitted with SWs (median for GSWs = 25; for SWs = 16; P = 0.086) although the difference did not reach statistical significance (Table 2). In addition, NISS scores were significantly higher in patients admitted for GSWs compared to patients with SWs (median NISS = 34; range = 3–75; for GSWs = 34; for SWs = 26; P = 0.045) (Table 2). The two patients who were admitted with “other” types of injury had ISS scores of 38 and 26, and NISS scores of 43 and 34, respectively. Nine out of 10 (90.0%) GSW victims and 16 out of 26 (61.5%) SW victims had ISS >15 (P = 0.0024). During the seven-year period, there was no increased risk for second-look CT in patients with GSWs compared to other types of penetrating trauma (odds ratio [OR] = 1.24; 95% confidence interval [CI] = 0.59–2.58; P = 0.56).

Table 1.

Patient characteristics.

Characteristics
No. of patients	38
Age (years)	31.5 (17–73)
Sex
Male	36 (94.7)
Female	2 (5.3)
ISS	21 (1–75)
NISS	34 (3–85)
Type of injury
SW	26 (68.4)
GW	10 (26.3)
Other injury	2 (5.3)
Survived to discharge (reciprocal of 30-day mortality)	36 (94.7)
ICU days (mean)	4.8

Values are given as n (%) or median (range) unless otherwise indicated.

GSW, gunshot wound; ICU, intensive care unit; ISS, Injury Severity Score; NISS, New Injury Severity Score; SW, stab wound.

Table 2.

Comparison between SWs and GSWs.

	SW	GW	P
No. of patients	26	10
Mean age (years) (range)	37.7 (17–65)	26 (20–39)	0.66*
Sex
Male	25	10
Female	1	0
Survived to discharge	24 (92.3)	9 (90)	0.82^†
ISS	16 (1–75)	25 (9–50)	0.086*
NISS	26 (3–75)	34 (21–57)	0.045*
Patients with ISS >15	16/26 (61.5)	9/10 (90.0)	0.0024^†
Mean ICU days	3	7.8	0.092*

Values are given as n (%) or median (range) unless otherwise indicated.

*Wilcoxon test.

^†Chi-square test.

GSW, gunshot wound; ICU, intensive care unit; ISS, Injury Severity Score; NISS, New Injury Severity Score; SW, stab wound.

Overall, the average ICU-LOS was 4.8 days. On average, GSW victims’ stay in the ICU tended to be longer (7.8 days) than for SW victims (3 days) (P = 0.092) although this did not reach statistical significance. Two patients (both male) died within 30 days of being admitted, rendering an overall survival rate (i.e. reciprocal of 30-day mortality) of 94.7% (36/38). Patient characteristics are demonstrated in Tables 1 and 2. Of the 38 patients in this cohort, 15 had laparotomy, eight had thoracotomy, and five had combined thoracotomy and laparotomy. A further 10 patients underwent a more specific type of intervention, sometimes in combination with thoracotomy and/or laparotomy, which included exploration of the soft tissues of neck and extremities as well as angiographic interventions.

Out of the 38 patients, 20 (52.6%) had additional trauma-related findings at postoperative CT that were not described in the surgical reports and not diagnosed preoperatively on clinical examination nor with a radiograph in the trauma bay. Eight patients (21.1%) had additional trauma-related findings within the surgical field, 11 (28.9%) patients outside the surgical field, and 1 (2.6%) patient had additional findings both within and outside the surgical field. Most of the additional findings observed were relatively minor and warranted follow-up in some cases but not requiring additional surgical or angiographic intervention. These findings included small liver, splenic, or kidney lacerations, blood in the renal pelvis, perirenal hematoma, pneumothorax, lung contusions and lacerations, psoas muscle injury, intracranial bleeding, foreign objects (bullet fragments), and a variety of skeletal injuries (including fractures of the sternum, scapula, fibula, ribs, C1 vertebrae, and comminuted L5 vertebrae fracture).

At our institution it is common practice in the trauma bay to perform radiographs of the chest, pelvis, and/or extremities if major injuries are suspected. A total of 7 (18.4%) patients had one or more fractures detected at postoperative CT that were not diagnosed clinically/perioperatively and not seen on radiographs taken in the trauma bay. Most of these fractures were minor and included fractures of the ribs, sternum, scapula, and fibula. Two patients had more serious fractures detected at the postoperative CT that included a comminuted fracture of the L5 vertebrae and fracture of the anterior tubercle of the C1. However, both fractures were regarded as stable and did not require surgical intervention.

Although most of the additional findings at the postoperative CT were relatively minor, there were 6 (15.8%) patients who had previously unidentified or underestimated findings severe enough to warrant additional surgery or angiography (Table 3). Of those six patients, two had previously unidentified foreign objects, one of whom had a dislodged knife blade intracranially, and the other had a bullet fragment lodged in the soft tissues of the neck near the internal carotid artery. Angiographic intervention was performed on two patients: one had active bleeding from an intercostal artery at CT that had ceased spontaneously during angiography and therefore no further treatment ensued. The other patient had a traumatic intraparenchymal pseudoaneurysm in the right kidney at postoperative CT imaging that was subsequently coiled in the angiography suite (Fig. 1). Another patient had more severe liver laceration than expected that, in combination with clinical findings, led to re-operation. Ultimately, no further surgical repair was required during second-look operation. Lastly, one patient had a proximal ulna fracture visualized on the CT scout image that proved to be a Monteggia fracture-dislocation and needed a subsequent open surgical reduction and internal fixation.

Fig. 1.

Retroperitoneal injuries are often difficult to fully evaluate during routine trauma laparotomy. (a) Coronal contrast-enhanced multidetector computed tomography image obtained in the arterial phase demonstrates pseudoaneurysm (arrow) in the upper right kidney. (b, c) The patient underwent a subsequent angiography and the pseudoaneurysm was coiled.

Table 3.

Patients with additional trauma-related findings on postoperative CT that warranted further surgery or interventional angiography.

No.	Age (years)	Sex	Mechanism of injury	ISS	NISS	Reason for further intervention	Type of intervention
1	46	M	SW	42	45	Dislodged knife blade intracranially	Craniotomy with removal of knife blade
2	23	M	GSW	43	50	Active bleeding in pleural space	Angiographic intervention; bleeding had ceased during angiography
3	24	M	GSW	29	34	Retained bullet near the internal carotid artery	Reoperation with removal of retained bullet
4	52	M	SW	26	34	Pseudoaneurysm in the right kidney	Angiography with embolization
5	28	M	SW	26	34	Unexpected liver laceration that in combination with clinical findings led to explorative laparotomy	Explorative laparotomy; no surgical repair required during second-look operation
6	40	F	Other	38	43	Monteggia fracture dislocation (seen on CT scout image)	Open reduction and fixation

CT, computed tomography; GSW, gunshot wound; ISS, Injury Severity Score; NISS, New Injury Severity Score; SW, stab wound.

The six patients who needed additional surgery had a median ISS score of 34 (range = 26–43), which was significantly higher than for those who did not need a second operation (17, range = 1–75) (P = 0.0068) and spent more time at the ICU (10.2 vs. 3.8 days; P = 0.011) (Table 4). Out of those six patients, three were admitted for GWs, two for SWs and one for “other” type of injury. There was no increased risk for second operation in patients with GSWs compared to other types of penetrating trauma (OR = 3.57; 95% CI = 0.59–21.75; P = 0.31).

Table 4.

Comparison of patients who needed a second intervention and those not needing additional intervention.

	Second operation (n = 6)	No second operation (n = 32)	P
Male/Female	5/1	31/1	-
Mean age (years) (range)	35.5 (23–51)	30.8 (17–73)	0.24*
ISS	34 (26–43)	17 (1–75)	0.0068*
NISS	39 (34–50)	28 (3–75)	0.063*
ICU days	10.2 (3–21)	3.8 (0–25)	0.011*
MOI: GSW/SW + other	3/3	7/25	0.31^†

Values are given as n (%) or median (range) unless otherwise indicated.

*Wilcoxon test.

^†Fisher’s exact test.

GSW, gunshot wound; ICU, intensive care unit; ISS, Injury Severity Score; MOI, mechanism of injury; NISS, New Injury Severity Score; SW, stab wound.

Of the 38 patients in the cohort, 2 (5.3%) succumbed to their injuries within 30 days of admission to the trauma center. One had self-inflicted penetrating injuries to the neck and the other one had received multiple GSWs to the upper and lower extremities as well as to the thorax and abdomen. Neither patient had additional injuries at the postoperative CT that required further intervention.

Discussion

Patients with penetrating injuries pose a significant challenge to surgeons and radiologists alike. During emergency surgery, a complete exploration of all body compartments may not be performed, particularly if damage control techniques are used. In challenging locations, such as the retroperitoneum and deep pelvis, CT is an important tool for comprehensive assessment of all injuries. Only a few studies have evaluated the utility of postoperative CT imaging after urgent surgery (2,3,6,7). To our knowledge, there is only one previous study that has focused entirely on postoperative CT in patients who had emergency surgery due to penetrating trauma (7).

Haste et al. (2) and Weis et al. (6) performed similar retrospective studies. There were, however, major differences in the design of these studies compared to ours. Both studies included patients with both blunt and penetrating trauma and evaluated the efficacy of postoperative CT only after laparotomy.

Further, a study published previously partially shared data with the current study but included only patients with penetrating trauma to the chest. In that study, nine patients had emergency surgery before CT imaging. CT findings altered further treatment in 5/9 (55.6%) patients (3).

In our study, 20 (52.6%) patients had trauma-related findings at the postoperative CT that had not been diagnosed before or during surgery. However, most of these injuries were minor and did not warrant further surgery or angiographic intervention. In comparison, Mendoza et al. (7) and Haste et al. (2) showed that 38 of 73 (52.1%) and 61 of 90 (67.8%) trauma patients, respectively, had unexpected and/or previously undiagnosed injury at early postoperative CT. Additionally, 10 out of 73 (13.7%) (7) and 8 out of 90 (8.9%) (2) patients needed further surgery or interventional angiography, respectively, due to unexpected findings at early postoperative CT imaging. A higher rate was noted in our study where 6/38 (15.8%) patients had CT findings postoperatively that warranted additional interventions. It should be noted, however, that among those six patients, one underwent second-look operation without needing further surgical repair. In addition, one patient had an unidentified injury diagnosed at CT scout image (proximal ulnar fracture) that probably would have been suspected/diagnosed clinically under secondary survey or later when the patient had stabilized. Further, the proximal ulnar fracture was probably due to a combination of penetrating and blunt trauma. The six patients who needed additional surgery had a median ISS of 34 (range = 26–43), which was higher than for those who did not need a second operation (ISS = 17; range = 1–75) (P = 0.0068) and spent more time at the ICU (10.2 vs. 3.8 days; P = 0.011).

This study is in line with the results from other studies showing that trauma patients are relatively young and much more often men than women (2,3,6,8–10). In our cohort of 38 patients, only 2 (5.3%) were women, both of whom had self-inflicted injuries. Most of the men in this study (34/36, 94.4%) had injuries due to presumed interpersonal violence. Of the two remaining male patients, one had self-inflicted SWs to the neck and the other was involved in an unintentional accident with a plough blade that penetrated the patients’ right flank.

The most common injury mechanism in our study was stabbing (26/38, 68.4%) with fewer being due to GSWs (10/38, 26.3%), which is in accordance with other Scandinavian studies (3,4,8,11). This is in contrary to many USA-based studies that show firearm injuries to be more common (1,2,7,12,13), likely reflecting that firearms are more easily accessible in the USA compared to most European countries. In Sweden, blunt trauma is the most common type of injury, responsible for approximately 90% of encountered injures. However, penetrating trauma has increased in recent years in Sweden from 6.7% to 9.0% between 2014 and 2019 (14). Stabbing is the dominating mechanism of injury in penetrating trauma in Sweden (3,8,14), which is in concurrence with other studies on trauma victims in Europe (4,8,10,11,15,16). However, it has been shown that among penetrating trauma in Stockholm, there was a significant increase in firearm injures from 16% in 2005 to 36% in 2016 (8).

Overall, patients admitted for GSWs were more severely injured with higher ISS and NISS compared to SW victims. This pattern was also seen when looking at the subset of patients who had ISS >15 with 9/10 (90%) GSW victims having ISS >15 versus 16/26 (61.5%) in the SW group (P = 0.0024).

The present study has some limitations. Our analysis is retrospective, and patients were only selected from a single level 1 trauma center. Therefore, the results may not be generalized to other hospitals and trauma centers that have different patient and injury characteristics as well as differing management practices. Another limitation is the small cohort size with limited statistical power. Due to the retrospective design, it is also possible that not every suspected or even obvious trauma-related finding was documented by the surgeon or other clinicians. Finally, our analysis included no control group that could have assessed whether postoperative CT findings actually resulted in an increased rate of intervention compared to clinical judgment alone.

In conclusion, postoperative CT imaging after emergency surgery in penetrating trauma is an important tool in evaluating the injury panorama and revealing previously undiagnosed and/or unexpected injuries. Out of 38 patients, 6 (15.8%) had findings at postoperative CT that warranted second operation or angiographic intervention.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Kolbeinn Halldorsson

Mari Nummela

Sigurveig Thorisdottir

Seppo Koskinen

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