Anastomotic Outcomes in Military Exploratory Laparotomies in the Modern Combat Era

Abstract

Background

Intestinal anastomoses in military settings are performed in severely injured patients who often undergo damage control laparotomy in austere environments. We describe anastomotic outcomes of patients from recent wars.

Methods

Military personnel with combat-related intra-abdominal injuries (June 2009-December 2014) requiring laparotomy with resection and anastomosis were analyzed. Patients were evacuated from Iraq or Afghanistan to Landstuhl Regional Medical Center (Germany) before being transferred to participating U.S. military hospitals.

Results

Among 341 patients who underwent 1053 laparotomies, 87 (25.5%) required ≥1 anastomosis. Stapled anastomosis only was performed in 57.5% of patients, while hand-sewn only was performed in 14.9%, and 9.2% had both stapled and hand-sewn techniques (type unknown for 18.4%). Anastomotic failure occurred in 15% of patients. Those with anastomotic failure required more anastomoses (median 2 anastomoses, interquartile range [IQR] 1-3 vs. 1 anastomosis, IQR 1-2, P = .03) and more total laparotomies (median 5 laparotomies, IQR 3-12 vs. 3, IQR 2-4, P = .01). There were no leaks in patients that had only hand-sewn anastomoses, though a significant difference was not seen with those who had stapled anastomoses. While there was an increasing trend regarding surgical site infections (SSIs) with anastomotic failure after excluding superficial SSIs, it was not significant. There was no difference in mortality.

Discussion

Military trauma patients have a similar anastomotic failure rate to civilian trauma patients. Patients with anastomotic failure were more likely to have had more anastomoses and more total laparotomies. No definitive conclusions can be drawn about anastomotic outcome differences between hand-sewn and stapled techniques.

Keywords

military laparotomy anastomotic technique anastomotic failure

Key Takeaways

15% of combat casualties who had at least one anastomosis had anastomotic failure with the time to failure being a median of 3 days post-injury.

There was no significant difference in the technique used (hand-sewn vs. stapled), injury characteristics, or surgical site infections between the patients with and without anastomotic failure with the only significant factors being the number of total exploratory laparotomies and anastomoses.

Despite higher severity with battlefield trauma, the proportion of anastomotic failure was similar to what was reported in civilian literature.

Introduction

The management of intestinal injury in combat settings has changed significantly over the past century. Dating back to World War I, nonintervention with selective primary repair was the preferred approach for gastrointestinal injuries.¹ More recently during the wars in Iraq and Afghanistan, damage control laparotomy with delayed primary anastomoses became commonplace.² Intestinal anastomoses in military settings are performed in severely injured patients who often undergo damage control laparotomy in austere environments. These patients commonly have a high associated burden of injury and are potentially at a greater risk of anastomotic complications.³ Abdominal trauma represents approximately 10% of the injuries from the recent conflicts in Iraq and Afghanistan, with abdominal operations accounting for at least 13% of surgical procedures performed on combat casualties.⁴

The anastomotic outcomes for civilian trauma and acute care surgery patients have been previously described.^5-7 Leak rates vary from 6 to 15% and have similar outcomes between stapled and hand-sewn techniques. While there exists a debate in elective civilian cases whether stapled intestinal anastomoses are more cost-effective than hand-sewn anastomoses,⁸ no differences in outcomes between the two techniques have been demonstrated.⁹ The anastomotic outcomes in military settings from the wars in Iraq and Afghanistan have not yet been described. Herein, we sought to characterize the outcomes of anastomoses performed in military settings and determine if any differences exist between the techniques used.

Methods

This study was approved by the Institutional Review Board (IRB) of the Uniformed Services University of the Health Sciences (Bethesda, MD). Data were collected through an IRB-approved waiver of consent for use of de-identified data not obtained through interaction or intervention with human subjects. Data were collected as part of the Trauma Infectious Disease Outcomes Study (TIDOS), an observational study of infectious complications in combat casualties.^10,11 Criteria for inclusion in TIDOS were being active-duty or Department of Defense beneficiary, age 18 years or older, being injured while deployed (June 1, 2009-December 31, 2014), and requiring medical evacuation to Landstuhl Regional Medical Center before transition to participating military hospitals in the United States. The participating hospitals are Walter Reed National Military Medical Center (previously was Walter Reed Army Medical Center and National Naval Medical Center prior to September 2011) and Brooke Army Medical Center. For this study, the population was restricted to military personnel with combat-related intra-abdominal injuries requiring laparotomy with intestinal resection and anastomosis.

Patient demographics (ie, age at injury and sex), injury characteristics (ie, Injury Severity Score [ISS] and mechanism of injury), and early trauma care data (ie, blood transfusion and shock index) were collected from the Department of Defense Trauma Registry (DoDTR),¹² while infection-related information (ie, surgical site infections [SSIs]) was obtained through the DoDTR TIDOS Infectious Disease module.¹⁰ Data related to abdominal surgery (ie, laparotomy, anastomoses, and abdominal organ injury) and outcomes were retrospectively abstracted from medical records. Particular attention was paid to the anastomotic technique used where this information was available. In addition to visualized anastomotic breakdown, anastomotic failure was defined as the presence of intra-abdominal abscess, enterocutaneous fistula, or subsequent intraperitoneal spillage deemed to be related to anastomotic leak. Retrospective review of clinical findings, medical records, imaging, and laboratory results were utilized to classify abdominal SSIs as superficial, deep incisional, or organ space, as previously described.¹³

Chi-squared or Fisher’s exact tests were used to detect differences between patients with and without anastomotic failure for categorical variables, and the Kruskal-Wallis test was used for continuous variables. A P value <.05 was deemed statistically significant. Statistical analysis was performed using SAS version 9.4 (Cary, NC).

Results

Study Population

Among 4304 combat casualties, 341 patients underwent a total of 1053 laparotomies. Of these, 87 patients (25.5%) required at least one anastomosis and were included in the analysis. The median age was 24 years old (interquartile range [IQR]: 21-27 years), and 98.9% were male. Approximately 79% of patients were injured while on foot patrol, and the median ISS was 29 (Table 1). The patients in this series required a median of three exploratory laparotomies, and 75.9% had damage control laparotomies performed. Of note, 12.6% of patients had an abdominal vascular injury in addition to an intestinal injury that required resection and anastomosis. Among the 87 patients, there were 13 (15%) and 74 (85%) patients who did and did not have anastomotic failure, respectively. There were no significant differences between the two groups (Table 1).

Table 1.

Characteristics of Combat Casualties Undergoing Intestinal Anastomosis During Exploratory Laparotomy.

Characteristics, no. (%)	Total patients (N = 87)	Anastomotic failure		P-value
Characteristics, no. (%)	Total patients (N = 87)	Patients with (N = 13)	Patients without (N = 74)	P-value
Injury cause				.081
Blast-IED	28 (32.2)	4 (20.8)	24 (32.4)
Blast-non-IED	18 (20.7)	0	18 (24.3)
Non-blast	41 (47.1)	9 (69.2)	32 (43.2)
Injury Severity Score, median (IQR)	29 (24, 42)	29 (20, 48)	29 (26, 41)	.742
Blood transfusion, median (IQR)	11 (4, 23)	12.5 (3, 32)	11 (4, 23)	.877
Shock index, median (IQR)	.9 (.7, 1.3)	1.2 (.7, 1.4)	.9 (.7, 1.3)	.497
Damage control procedure	66 (75.9)	11 (84.6)	55 (74.3)	.726
Specific injury findings
Small bowel	63 (72.4)	8 (61.5)	55 (74.3)	.341
Colon	61 (70.1)	12 (92.3)	49 (66.2)	.097
Rectum	11 (12.6)	2 (15.4)	9 (12.2)	.667
Spleen	16 (18.4)	3 (23.1)	13 (17.6)	.700
Liver	14 (16.1)	1 (7.7)	13 (17.6)	.684
Gastric	6 (6.9)	0	6 (8.1)	.585
Biliary tree	3 (3.5)	0	3 (4.1)	∼1.00
Pancreas	5 (5.8)	2 (15.4)	3 (4.1)	.159
Duodenum	6 (6.9)	1 (7.7)	5 (6.8)	∼1.00
Kidney	10 (11.5)	3 (23.1)	7 (9.5)	.168
Retroperitoneal hema	16 (18.4)	1 (7.7)	15 (20.3)	.447
Bladder	8 (9.2)	1 (7.7)	7 (9.5)	∼1.00
Diaphragm	7 (8.1)	2 (15.4)	5 (6.8)	.280
Abdomen vascular	11 (12.6)	2 (15.4)	9 (12.2)	.667
Iliacs	7 (8.1)	2 (15.4)	5 (6.8)	.280
Inpatient stay, median days (IQR)	28 (15, 47)	30 (18, 69)	28 (15, 44)	.490

Abbreviations: IED, improvised explosive device; IQR, interquartile range.

Anastomotic Characteristics and Outcomes

Among the 87 patients, there was a median of two laparotomies prior to anastomosis with no difference between the patients who did and did not have anastomotic failure (Table 2). Stapled anastomosis only was performed in 57.5% of patients, while hand-sewn only was performed in 14.9%. Both stapled and hand-sewn techniques were used in 9.2% of patients, and the technique of anastomosis was unknown for 18.4%. There were no leaks in patients that had only hand-sewn anastomoses; however, a significant difference was not seen among those who had stapled anastomoses (P = .051). After excluding the 16 patients who had an unknown anastomosis type, the lack of significance regarding technique between those who did and did not have anastomotic failure remained (P = .19).

Table 2.

Anastomotic Characteristics and Outcomes.

Characteristics, no. (%)	Total patients (N = 87)	Anastomotic failure		P-value
Characteristics, no. (%)	Total patients (N = 87)	Patients with (N = 13)	Patients without (N = 74)	P-value
Exlap count, median (IQR)	3 (2, 4)	5 (3, 12)	3 (2, 4)	.013
Exlaps prior to anastomosis	2 (1, 3)	3 (1, 3)	2 (1, 3)	.292
Anastomosis type				.051
Both	8 (9.2)	3 (23.1)	5 (6.8)
Hand-sewn only	13 (14.9)	0	13 (17.6)
Stapled only	50 (57.5)	6 (46.2)	44 (59.5)
Unknown	16 (18.4)	4 (30.8)	12 (16.2)
Total anastomoses	1 (1, 2)	2 (1, 3)	1 (1, 2)	.030
Anastomosis connection
Large bowel to large bowel	19 (21.8)	4 (30.8)	15 (20.3)	.469
Small bowel to large bowel	23 (26.4)	6 (46.2)	17 (23.0)	.080
Small bowel to small bowel	58 (66.7)	8 (61.5)	50 (67.6)	.671
Anastomosis Failure type				NA
Non-abscess intra-abdominal infection	5 (5.7)	5 (38.5)	NA
Intra-abdominal abscess	1 (1.1)	1 (7.7)	NA
Fistula	2 (2.3)	2 (15.4)	NA
Intraperitoneal spillage	1 (1.1)	1 (7.7)	NA
Visualized breakdown	4 (4.6)	4 (30.8)	NA

Abbreviations: Exlap, exploratory laparotomy; IQR, interquartile range; NA, not applicable.

Time to anastomotic failure was a median of 3 days post-injury (IQR: 2-6 days). Of the 13 patients with anastomotic failure, 1 (7.7%) had an associated intra-abdominal abscess, 5 (38.5%) developed a non-abscess intra-abdominal infection, 2 (15.4%) developed an enterocutaneous fistula, 1 (7.7%) had intraperitoneal spillage, and 4 patients (30.8%) had visualized breakdowns on subsequent laparotomies. Those who had an anastomotic failure were more likely to have multiple anastomoses (median 2 anastomoses, IQR 1-3 vs. 1 anastomosis, IQR 1-2, P = .03) and required more total laparotomies (median 5 laparotomies, IQR 3-12 vs. 3, IQR 2-4, P=.01).

There was no difference in mortality between those who had anastomotic failures and those who did not (7.7% vs. 2.7%, P = .39; Table 3). The overall proportion of abdominal SSIs was 25.3% with no statistical difference between patients with and without anastomotic failure (38.5% vs. 23.0%, P = .24). After excluding superficial abdominal SSIs and restricting to deep incisional or organ space SSIs, there was the indication of an increasing trend toward more SSIs among patients with anastomotic failure (38.5% vs 16.2%); however, it was not significant (P = .062).

Table 3.

Outcomes of Patients Stratified by Occurrence of Anastomotic Failure.

Characteristics	Total patients (N = 87)	Anastomotic failure		P-value
Characteristics	Total patients (N = 87)	Patients with (N = 13)	Patients without (N = 74)	P-value
Surgical site infection (SSI) ^a	22 (25.3)	5 (38.5)	17 (23.0)	.236
Deep incisional or organ space SSIs	17 (19.5)	5 (38.5)	12 (16.2)	.062
Surgical management for SSI
Re-ex-lap	12 (13.8)	7 (53.9)	5 (6.8)	<.001
IR drain	9 (10.3)	3 (23.1)	6 (8.1)	.129
Skin opened	14 (16.1)	3 (23.1)	11 (14.9)	.432
TBI	34 (39.1)	3 (23.1)	31 (41.9)	.235
DVT	12 (13.8)	1 (7.7)	11 (14.9)	.684
PE	9 (10.3)	2 (15.4)	7 (9.5)	.618
Death	3 (3.5)	1 (7.7)	2 (2.7)	.388

Abbreviations: DVT, deep vein thrombosis; Exlap, exploratory laparotomy; IR, interventional radiology; PE, pulmonary embolism; TBI, traumatic brain injury.

^aincludes superficial, deep incisional, and organ space SSIs.

Discussion

This retrospective study on the anastomotic outcomes of recent military laparotomies demonstrated that patients with anastomotic failure in this series were more likely to have had a greater number of laparotomies as well as anastomoses. No leaks were seen in those who had hand-sewn only anastomoses, although this was not a statistically significant difference. Therefore, we did not see any notable outcome differences between stapled and hand-sewn technique.

In this military population, we observed a similar leak rate to anastomoses reported in civilian settings. Brundage et al⁶ described a leak rate of 13% for stapled anastomoses and 5% for hand-sewn that was not statistically significantly different. In addition, a study of penetrating colon injuries found that 6.3% of stapled colorectal anastomoses leaked compared to 7.8% of hand-sewn anastomoses (P = .69).⁷ Furthermore, Bruns et al⁵ reported a leak rate of 15.4% for hand-sewn anastomoses and 10.6% for stapled anastomoses in an assessment of civilian acute care surgery patients. Despite the military patients in our study being generally more severely injured, our leak rate was comparable to these prior civilian studies. In particular, the mean ISS for two of the previously described series comprising trauma patients was 16.5 and 21.9, respectively.^6,7 In our study, the median ISS was 29, which is slightly higher as compared to a prior series of military patients where the median ISS was 25 for those who underwent therapeutic laparotomy from 2002 to 2011.¹⁴ An in-theater evacuation time of 60 minutes or less was mandated in June 2009,¹⁵ and this may have accounted for why more severely injured patients were reported in our study. The overall burden of injury due to the high prevalence of blast injuries (53%) also likely contributed to the anastomotic outcomes of our patients.

Although there was no statistical difference in the proportion of SSIs, whether assessing all SSIs or restricting to deep incisional/organ space SSIs, between patients who leaked and who did not in our study, there does appear to be a higher incidence of abdominal SSIs in military patients who undergo intestinal anastomosis. Abdominal SSIs have previously been described in a broader series of military laparotomies using the TIDOS population. As noted by Bozzay et al, 14.4% of 341 combat casualties who underwent combat-related exploratory laparotomies developed an abdominal SSI with the majority being organ space or deep incisional (12.0%).^13,16 In this more restricted TIDOS population, the overall proportion of any SSIs was 25.3%, while it was 19.5% for either deep incisional or organ space SSIs and it is possible that distinguishing a true meaningful difference regarding the development of abdominal SSIs between the groups was hindered by the low numbers included in the study.

Over 90% of patients in our study had an open abdomen during the course of their care, and the median number of exploratory laparotomies prior to anastomosis was two. Furthermore, approximately 76% of patients had damage control procedures performed. This compares to the 77% incidence of damage control laparotomies reported in Smith et al.² While there was not an association in our study with having had an open abdomen and experiencing anastomotic leak, we did find that patients with anastomotic failure more frequently had a greater number of both anastomoses and laparotomies. Significant consequences, of course, are associated with anastomotic failures. Beyond the infectious complications and need for further intervention, anastomotic leaks likely play a role in contributing to the high rate of incisional hernias after military laparotomies, which is estimated to be as high as 19.1%.¹⁷

This study does include limitations inherent with retrospective analyses. Additionally, incomplete or missing documentation for patients as they were transferred through different levels of care also contributed to a small number of patients for which the technique of anastomosis was not known. Last, complete follow-up information was not available for some patients.

Operations performed in the forward deployed environments are at times limited by the supplies that are available. Thus, combat surgeons should be adept at being able to perform both hand-sewn and stapled anastomotic techniques. Overall, the results of this study support that combat surgeons should be able to perform intestinal anastomoses with the technique best supported by their patient’s clinical circumstances, resources available, and prior training.

Footnotes

Acknowledgments

We are indebted to the Infectious Disease Clinical Research Program Trauma Infectious Disease Outcomes Study team of clinical coordinators, microbiology technicians, data managers, clinical site managers, and administrative support personnel for their tireless hours to ensure the success of this project.

Declaration of Conflicting Interests

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

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Support for this work (IDCRP-024) was provided by the Infectious Disease Clinical Research Program (IDCRP), a Department of Defense program executed through the Uniformed Services University of the Health Sciences, Department of Preventive Medicine and Biostatistics through a cooperative agreement with The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. (HJF). This project has been funded by the National Institute of Allergy and Infectious Diseases, National Institutes of Health, under InterAgency Agreement Y1-AI-5072, the Defense Health Program, U.S. DoD, under award HU0001190002, and the Department of the Navy under the Wounded, Ill, and Injured Program (HU0001-10-1-0014). The funders had no role in study design, data collection, data analysis, data interpretation, or writing the manuscript.

Disclaimer

The views expressed are those of the authors and do not reflect the official views of the Uniformed Services University of the Health Sciences, Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., the National Institute of Health or the Department of Health and Human Services, Brooke Army Medical Center, Walter Reed National Military Medical Center, the U.S. Army Medical Department, the U.S. Army Office of the Surgeon General, the Department of Defense, or the Departments of the Army, Navy or Air Force. Mention of trade names, commercial products, or organizations does not imply endorsement by the U.S. Government.

References

Steele

Wolcott

Mullenix

, et al.

Colon and rectal injuries during Operation Iraqi Freedom: are there any changing trends in management or outcome?

Dis Colon Rectum. 2007;50(6):870-877.

Smith

Beech

Lundy

Bowley

. A prospective observational study of abdominal injury management in contemporary military operations: damage control laparotomy is associated with high survivability and low rates of fecal diversion. Ann Surg. 2015;261(4):765-773.

Remick

. Leveraging trauma lessons from war to win in a complex global environment. US Army Med Dep J. 2016;2016(2-16):106-113.

Stockinger

Turner

Gurney

. Abdominal trauma surgery during recent US combat operations from 2002 to 2016. J Trauma Acute Care Surg. 2018;85(1S Suppl 2):S122-S128.

Bruns

Morris

Zielinski

, et al. Stapled versus hand-sewn: a prospective emergency surgery study. An American Association for the Surgery of Trauma multi-institutional study. J Trauma Acute Care Surg. 2017;82(3):435-443.

Brundage

Jurkovich

Hoyt

, et al. Stapled versus sutured gastrointestinal anastomoses in the trauma patient: a multicenter trial. J Trauma. 2001;51(6):1054-1061.

Demetriades

Murray

Chan

, et al. Handsewn versus stapled anastomosis in penetrating colon injuries requiring resection: a multicenter study. J Trauma. 2002;52(1):117-121.

Schineis

Fenzl

Aschenbrenner

, et al. Stapled intestinal anastomoses are more cost effective than hand-sewn anastomoses in a diagnosis related group system. Surgeon. 2020;S1479-666X(20):30146-30153. doi:10.1016/j.surge.2020.09.002.

Neutzling

Lustosa

Proenca

da Silva

Matos

. Stapled versus handsewn methods for colorectal anastomosis surgery. Cochrane Database Syst Rev. 2012;2:CD003144.

10.

Tribble

Conger

Fraser

, et al. Infection-associated clinical outcomes in hospitalized medical evacuees after traumatic injury: Trauma lnfectious Disease Outcome Study. J Trauma. 2011;71(1 suppl l):S33-S42.

11.

Tribble

Murray

Lloyd

, et al. After the battlefield: infectious complications among wounded warriors in the Trauma lnfectious Disease Outcomes Study. Mil Med. 2019;184(Suppl 2):18-25.

12.

Eastridge

Jenkins

Flaherty

Schiller

Holcomb

. Trauma system development in a theater of war: experiences from operation Iraqi Freedom and operation enduring freedom. J Trauma. 2006;61(6):1366-1373.

13.

Bozzay

Walker

Schechtman

, et al. Risk factors for abdominal surgical site infection after exploratory laparotomy among combat casualties. J Trauma Acute Care Surg. 2021;91(2S):S247-S255.

14.

Mitchell

Hutchison

Becker

Aden

Blackbourne

White

. Nontherapeutic laparotomy in American combat casualties: a 10-year review. J Trauma Acute Care Surg. 2014;77(3 Suppl 2):S171-S175.

15.

Kotwal

Howard

Orman

, et al. The effect of a golden hour policy on the morbidity and mortality of combat casualties. JAMA Surg. 2016;151(1):15-24.

16.

Bozzay

Walker

Schechtman

, et al. Outcomes of exploratory laparotomy and abdominal infections among combat casualties. J Surg Res. 2021;257(1):285-293.

17.

Moas

Eskridge

Clouser

Kurapaty

Dyke

Souza

. Incisional hernia incidence following laparotomy for combat trauma: Investigating 15 years of US war surgery. J Trauma Acute Care Surg. 2020;89(2S Suppl 2):S200-S206.