MILITARY MEDICINE, 178, 11:1222, 2013

The Injury Burden of Recent Combat Operations: Mortality, Morbidity, and Return to Service of U.K. Naval Service Personnel Following Combat Trauma Surg Lt Cdr Jowan G. Penn-Barwell, Royal Navy*t; Surg Lt Cdr Charles A. Fries, Royal Navy*f; Surg Lt Philippa M. Bennett, Royal Navy*; Surg Capt Mark Midwinter, Royal Navy*; Surg Capt Adrian B. Baker, Royal Navyf ABSTRACT Objectives: The study establishes the functional outcomes of service personnel injured in current conflicts by correlating data on initial injury to the findings of medical boards after trauma and reconstructive treatment. Data comprehensively include all casualties of the Royal Navy and Royal Marines and all functional outcomes. Methods: Details of all casualties from 2003 to 2010 taken from the Joint Theatre Trauma Registry and records of all medical boards relating to these personnel were analysed. Population at risk and probability of survival data were calculated. Results: There were 221 casualties: 54 (24%) were fatalities; of 167 survivors, 21 (9% of total) were medically discharged; 26 (12%) were placed in reduced fitness category and 120 (55%) retumed to full duty. Casualty risk per year of operational service for Naval Service personnel was 4.6%. New injury severity score and functional outcome were closely correlated, with specific exceptions. There were 3 unexpected survivors and no unexpected fatalities. Extremity injuries predominate in survivors. Conclusions: The Defence Medical Service (DMS) provides excellent trauma atnd rehabilitative care. The authors contend that this is a valid proxy for other larger coalition formations. Specific injury pattems have higher impact on functional outcomes; future research efforts should focus on these areas.

INTRODUCTION The conflicts in Iraq and Afghanistan have been the most significant military operations in the first decade of the 21st century. The burden of these conflicts in terms of mortality and morbidity is emotive and has received significant public attention. The recognized improvements in acute care have resulted in a group of survivors with more severe injuries than in previous conflicts.' This places a greater demand on surgical reconstruction and subsequent rehabilitation. Several invesligators have looked separately at fatality rates,^ pattems of injury,^''* and subsequent recovery.^'^ Despite this, the full spectrum of combat trauma sustained on the battlefield including the injuries sustained, fatality rates, residual injury burden, and the long-term implications for survivors

•Academic Department of Military Surgery and Trauma, Royal Centre for Defence Medicine (RCDM), ICT Research Park, Vincent Drive, Edgbaston, Birmingham B15 2SQ, United Kingdom. flnstitute of Naval Medicine, Crescent Road, Alverstoke, Gosport, Hants P012 2DL, United Kingdom. This is an original study and has not been presented or published elsewhere. The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Ministry of Defence or Her Majesty's Government. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. None of the authors have any conflicts of interest with the subject of this study. All the authors are serving officers in the Royal Navy. doi: 10.7205/MILMED-D-13-00180

1222

has been poorly characterized in the literature, as the size and complexity of military formations and their supporting medical chains have thwarted attempts to get complete data sets. The Naval Service of the United Kingdom, comprising the Royal Navy (RN) and the Commandos of the Royal Marines (RM), has been continuously involved in the conflicts of Iraq and Afghanistan. Uniquely among the three services, the Naval Service operates in all domains of the battlespace: sea, land, and air, and therefore can be regarded as a surrogate for the wider military. Most significantly the Naval Service operates a single, centralized, occupational medicine board that assesses the extent of the recovery of all injured personnel and their ability to retum to work. The research team is therefore able to study a data set that is comprehensive; not only in capturing data on all personnel killed or injured during these conflicts, but also in charting their progress from point of injury, until the end of their joumey of reconstruction and rehabilitation. The aim of this study was to (i) determine the rate of fatality and injury amongst Naval Service personnel deployed on operations; (ii) examine the effect on casualty survival of acute care services; (iii) determine the ability of reconstructive and rehabilitation services to retum Naval Service personnel to active duty. It is the authors' belief that extrapolating these data to larger formations of coalition forces is valid, based on the completeness of the source data, and that doing so is highly instructive in establishing the current state of the art of acute trauma care, reconstructive surgery, and rehabilitation services.

MILITARY MEDICINE, Vol. 178, November 2013

Injury Burden of Recent Comhat Operations in U.K. Naval Service Personnel

METHODS This study was approved and registered with the U.K.'s loint Medical Command and conducted at the Institute of Naval Medicine. The Naval Service operates a single, centralized Naval Service Medical Board of Survey (NSMBOS) for evaluating all injured sailors and marines. Its purpose is to determine the extent of an individual's recovery and their fitness for further military service. This generates a review of the full spectrum of injuries sustained, what recovery has been made from them, and the medical input at each stage. Functional outcome is described both in terms of the ability to perform functions required of a serviceperson, and those of daily living and recreation. The Defence Analytical Services Agency provided the authors with data on all RN and RM personnel that had deployed to either Iraq or Afghanistan from the invasion of Iraq in March 2003 to September 2010. Data on the length of deployments were also gathered. The number of deployed RN and RM personnel was multiplied by the number of days that they had served in operational theatre to give persondays at risk: this was then divided by 365 to give personyears at risk (PYAR). Because of the data availability, it was only possible to calculate PYAR for the period of April 2006 to September 2010. The casualty rate for this period was, therefore, calculated by obtaining the corresponding number of deployed personnel from this period. The DMS Joint Theatre Trauma Registry (ITTR) is an electronic database of prospectively gathered information collected by trained research nurses, working both in deployed medical facilities and in the Royal Centre for Defence Medicine in the United Kingdom. All cases of trauma fatalities, cases triggering a "trauma-call" on presentation to deployed medical facilities, or those whose injuries resulted in repatriation the United Kingdom are recorded. The JTTR was searched for all RN and RM personnel injured in the invasion of Iraq between March 2003 and September 2010. Demographic information, data regarding initial injuries, NISS, mechanism of injury, and treatment information were also collected from the JTTR. These cases were crosschecked against the records of the NSMBOS up to September 2011. The 12-month lag period between injury and NSMBOS data collection is a result of Naval regulations, which state that all personnel must be referred to NSMBOS within 12 months of the onset of medical problems. Referral to the NSMBOS can result in one of three outcomes: (1) A recommendation for medical discharge. (2) Returning of an individual to full duties. (3) Assigning an individual to a reduced medical category (known as medical downgrading): this entails restrictions on the individual's ongoing mihtary duties (e.g., no running, no load carrying). A detailed narrative summary is also provided.

MILITARY MEDICINE, Vol. 178, November 2013

For the purposes of this study individuals identified from JTTR and NSMBOS data were, therefore, placed in one of four categories: (1) (2) (3) (4)

Fatality Medical discharged Returned to full duty (RTD) Medically downgraded

Probability of survival (Ps) was calculated using PsO9 methodology developed by the Trauma and Audit Research Network, an updated version of Trauma and Injury Severity Score methodology, based on injury severity score, age, and initial Glasgow Coma Scale.' Statistical Analysis The NISS scores in the four outcome groups were compared using a one-way ANOVA. Numbers of residual injuries were compared using a Mann-Whitney test. RESULTS There were 221 casualties in the study period: 54 of these (24%) died. Of the 167 survivors 21 (9% of total casualties) were medically discharged from the Naval Service and 26 (12% of total casualties) were placed in a reduced fitness category with medical restrictions placed on their continued military service. A total of 120 individuals (54% of total casualties and 72% of survivors) recovered sufficiently to RTD without any restrictions on their future service. The mean age of all casualties was 26.2 (SD 5.9). Table I details the mechanisms of injury. There was a 4.6% casualty risk per year of operational service for Naval Service personnel between April 2006 and September 2010. Of the 54 fatalities, 48 were killed outright leaving only six that survived to reach any form of medical care and therefore have physiological observations recorded allowing Ps to be calculated: the mean was 12% (range 7.5-24.4%). Unexpected survival is indicated by a Ps of less than 50%: three survivors were found to be in this category with a mean Ps of 18% (range 7.5-22.5%) and a mean NISS of 72 (range 66-75). There were no unexpected deaths, that is all casualties with a Ps of 50% or greater survived. NISS correlates closely to the four NSMBOS outcome groups {p < 0.0001). Sixteen survivors with an NISS >20 have RTD without any restrictions on their military service TABLE L Mechanism Blast

GSW Air Crash MVC

Mechanism of Injury With Uncommon Mechanisms Excluded to Protect Anonymity n

%

131 57 15 12

59 26 7 5

GSW, gun-shot wound; MVC, motor vehicle collision.

1223

Injury Burden of Recent Combat Operations in U.K. Naval Service Personnel





60'

w

40 •

Z



• •

20 — : — ' t



FIGURE 1. Outcomes by injury severity with mean and 95% CI intervals. NISS, New injury severity score; RTD, retum to duty.

(Fig. 1). Of the survivors that did not RTD there was a mean of 3.0 distinct injuries at the time of presentation at the NSMBOS: this was 2.7 in those who were medically downgraded, and 3.2 in those who were medically discharged. DISCUSSION This study describes the medical impact of 7 years of combat operations on U.K. Naval Service personnel in Iraq and Afghanistan between March 2003 and September 2010. We found that a year of operational Naval Service involves a 4.6% risk of becoming a casualty. Among our population this study shows no unexpected fatalities, three unexpected survivors, and that 72% of those injured RTD. These results robustly show that the DMS delivers high-quality acute care, surgical reconstruction, and rehabilitation to those injured during recent conflicts. The extremely high NISS values and low Ps of the fatally injured casualties of our study population support the conclusions of other studies that the overwhelming majority of casualties that are killed die almost immediately from unsurvivable injuries.^ This is consistent with the finding that only 6 out of 54 fatalities survived their original injuries long enough to receive medical attention. Historically, it has been postulated that combat fatalities occur in a trimodal distribution: a majority of casualties die instantly from catastrophic injuries; a smaller proportion die in the acute phase from

1224

injuries that are beyond the abilities of the deployed trauma systems, for example, intracavity bleeding where no surgical team is available; and afinalsmaller group die in the later stages of their treatment, typically from overwhelming sepsis due to the burden of their injuries.^ The applicability of this model to recent military trauma deaths has been disputed.'°"'^ In Scope's study of deaths among Israeli troops 88% of deaths occurred within the first 30 minutes'^ and in Kotwal's 2011 article no recorded deaths were deemed as potentially survivable. "* Our findings add weight to the suggestion that further improvements in reducing mortality may produce marginal gains, as the standard of medical care is already very close to the physiological limits of these catastrophically injured patients. Therefore research efforts should additionally be directed toward reconstructive and regenerative strategies, with the aim of maximizing the functional outcomes of those who are injured. It is acknowledged that although further improvements in damage control resuscitation and surgery may offer only a limited improvement in mortality, improved resuscitation does influence longer term morbidity and functional impairment by mitigating ischemia-reperfusion injury, nerve injury, and minimizing other areas of morbidity such as infection, late pain syndrome, and postoperative recovery time. The proportion of casualties who died was 24% in this study population, a fatality rate considerably higher than others as available in the literature. It should be noted that during the study period, specifically the invasion of Iraq, two catastrophic helicopter crashes occurred in which all 15 casualties were fatalities, skewing the ratio of killed to injured. Recalculation of the fatality rate excluding these two incidents considerably reduces the mortality figure. Our results unsurprisingly show that those with more severe injuries, depicted by higher NISS values, were more likely to be fatally injured or medically discharged from Naval Service (Fig. 1). Conversely, those with less severe injuries were more likely to retum to full military duties. Despite these general trends, it is apparent that there are some outliers in the medically discharged and medically downgraded categories. There are 11 cases of individuals with a NISS of less than 10 whose injuries resulted in them being medically discharged or medically downgraded. The small numbers prevented statistical analysis, but it is noted that six of these individuals had a diagnosis of post-traumatic stress disorder (PTSD) and four had hearing or visual loss. Sensory loss limits further military service as impaired situational awareness has important safety implications. Significant upper-limb injury or amputation also falls into this category; Figure 2 compares the rates of retention in service versus discharge for specific injury types. The ability to recover sight or hearing, once lost because of traumatic injury, is limited with current management modalities. In addition, eventual functional outcome and reconstructive potential is manifest sooner than other injury types, particularly in musculoskeletal and psychiatric cases. For these reasons, discharge from the service, potentially at a relatively early

MILITARY MEDICINE, Vol. 178, November 2013

injury Burden of Recent Combat Operations in U.K. Naval Service Personnel

10 B l Medical discharge (21) O Medical downgrade (26)

FIGURE 2. Reasons for medical downgrading or a discharge, with more than 1 diagnosis possible per case.

Stage, is often the reality. Similarly, reconstruction of the upper limb is very challenging and, unlike in the case of the lower limb, prosthetics are very poor at restoring function— they lack the fine motor control or tactile feedback of the human hand. Specific injury pattems, such as ocular and hearing damage, have previously been identified as areas where improvements in injury prevention could have dramatic effects on functional outcome and therefore an individual's ability to continue v/ith a career in the military. An aggressive programme to improve facial, neck, eye, and hearing protection has been introduced to reduce the risk of these careerinfluencing injuries.^'^'^ Injury to the primary senses, such as sight and hearing, have a disproportionate impact on situational awareness and hence on continued military service. The significance of these injuries on functional potential is hard to overstate and highlights the requirement to improve current reconstructive technologies in these fields. Deploying staff with specific skill sets in managing these injuries is of great benefit and developing strategies to mitigate damage to these structures following injury is another active area of research with great potential. It may be commented that only six individuals in this study with a diagnosis of PTSD required medical downgrading or medical discharge. This figure is substantially lower than the published figures of seriously injured personnel from other studies.'^''^ It is important to note that methodology used in this study only identifies those with physical injuries and not psychiatric casualties. It is also reasonable to speculate that the stigma of mental illness makes those with concurrent physical injuries more inclined to identify physical wounds to the medical boards rather their psychiatric injuries.

MILITARY MEDICINE, Vol. 178, November 2013

PTSD can take many months or years to present and be diagnosed; it can be debated whether the follow-up period in this study was long enough to capture the full extent of this problem. In addition, 10 years ago, the RM had developed an organic, peer-led scheme for reducing the pathological effect of exposure to stressful experience.'^ This Trauma Risk Management program was in place before this study period and may have reduced the number of psychiatric casualties that would have otherwise been encountered, although this has yet to be shown by high-quality studies.'^'^ Of the survivors in this study there is a high-residual burden of injury with the extremities most commonly affected. U.S. military physicians have similarly found that the sequelae of extremity injuries form the vast majority of reasons for eventual medical discharge from military service following combat trauma. Cross et al found that 76% of medically discharged patients had a primary orthopaedic diagnosis. Identifying injury pattems, which resulted in relatively high numbers of medically discharged or medically downgraded service personnel, will help direct future research streams with respect to both training and equipment. The data presented include troops injured in both combat and support roles. However, this traditional distinction is less stark in modem counter-insurgency operations. With the available data, it is, therefore, not possible for the authors to comment on variations between injuries and fatalities among combat and support personnel. There are recognized weaknesses within this study. First, it is likely that a proportion of individuals have been temporarily placed in a medically downgraded category to allow ongoing treatment and maximal recovery. In such cases, the board will make a decision in the future that they have either sufficiently recovered to RTD—that is, they will be retained in service in a permanent reduced medical capacity—or that their residual injures are so significant to be incompatible with ongoing military service. Second, there is no way to recognize how significant individual injuries summate in any patient's overall injury burden and there might be bias to over-record injuries since this contributes to pension calculations. NISS was used in preference to injury severity score as it has been shown to correlate more accurately with the outcome.^' Also, despite Naval regulations that referral to NSMBOS take place within 12 months of injury, it is possible that in a few cases individuals have managed to postpone this to maximize their recovery prior to appearing before the board. Replicating this study across the wider U.K. military would be problematic because of the regional nature of the British Army's medical board. It should be noted that the medical care described is standardized across all three U.K. armed services, and that RN and RM personnel are involved in all areas of battlespace (on land, under sea, and in the air). The authors, therefore, contend that this study is a reliable surrogate for the broader British military, and to some extent coalition partners, who share similar medical systems.

1225

Injury Burden of Recent Combat Operations in U.K. Naval Service Personnel

Despite these acknowledged weaknesses, the authors believe that this study is valid in its characterization of the injury burden of combat trauma from recent conflicts. Although this study focuses on a single part of the U.K. military, it has the unique strength of comprehensively tracing every injured individual in an armed service from point of wounding to eventual occupational outcome. CONCLUSIONS This study confirms that the DMS delivers not only "exemplary" trauma care as described independently by the Healthcare Commission, but in retaining 87% of survivors of battlefield injuries during service, it provides excellent reconstruction and rehabilitation. ACKNOWLEDGMENTS The Academic Department of Military Emergency Medicine, Defence Analytical Services and Advice, and the NSMBOS are thanked for collecting, collating, and identifying the appropriate data for this article. The professionalism of the medical, nursing, and support staff of the Defence Medical Services and University Hospitals Birmingham for their work in treating the patients described in this study is gratefully acknowledged.

REFERENCES 1. Spinella PC, Perkins JG, Grathwohl KW, et al: Warm fresh whole blood is independently associated with improved survival for patients with combat-related traumatic injuries. J Trauma 2009; 66(4 SuppI): S69-76. 2. Eastridge BJ, Hardin M, Cantrell J, et al: Died of wounds on the battlefield: causation and implications for improving combat casualty care. J Trauma 2011; 71 :S4-8. 3. Champion HR, Holcomb JB, Lawnick MM, et al: Improved characterization of combat injury. J Trauma 2010; 68: 1139-50. 4. Owens BD, Kragh JF Jr, Macaitis J, et al: Characterization of extremity wounds in Operation Iraqi Freedom and Operation Enduring Freedom. J Orthop Trauma 2007; 21: 254-7.

1226

5. Patil ML, Breeze J: Use of hearing protection on military operations. J R Army Med Corps 2011; 157: 381-4. 6. Stinner DJ, Bums TC, Kirk KL, Ficke JR: Retum to duty rate of amputee soldiers in the current conflicts in Afghanistan and Iraq. J Trauma 2010; 68: 1476-9. 7. Boyd CR, Toison MA, Copes WS: Evaluating Trauma Care: the TRJSS Method. J Trauma 1987; 27:370-8. 8. Holcomb JB, McMullin NR, Pearse L, et al: Causes of death in U.S. Special Operations Forces in the global war on terrorism: 2001-2004. Ann Surg 2007; 245: 986-91. 9. Bellamy RF: The causes of death in conventional land warfare: implications for combat casualty care research. Mil Med 1984; 149: 55-62. 10. Lakstein D, Blumenfeld A: Israeli Army casualties in the second Palestinian uprising. Mil Med 2005; 170: 427-30. 11. Parker PJ: Casualty evacuation timelines: an evidence-based review. J R Army Med Corps 2007; 153: 274-7. 12. Scope A, Lynn M, Farkash U, et al: Military trauma life support: a comprehensive training program for military physicians. Mil Med 2001; 166: 385-8. 13. Scope A, Farkash U, Lynn M, et al: Mortality epidemiology in lowintensity warfare: Israel Defense Forces' experience. Injury 2001; 32: 1—3. 14. Kotwal RS, Montgomery HR, Kotwal BM, et al: Eliminating preventable death on the battlefield. Arch Surg 2011; 146: 1350-8. 15. Breeze J: Obtaining multinational consensus on future combat face and neck protection—proceedings of the Revision Military Protection Workshop. J R Army Med Corps 2012; 158: 141-2. 16. Breeze J, Allanson-Bailey LS, Hunt NC, et al: Surface wound mapping of battlefield occulo-facial injury. Injury 2012; 43: 1856-60. 17. McLay RN, Webb-Murphy J, Hammer P, et al: Post-traumatic stress disorder symptom severity in service members retuming from Iraq and Afghanistan with different types of injuries. CNS Spectr2012; 17: 11-5. 18. Terhakopian A, Sinaii N, Engel CC, et al: Estimating population prevalence of posttraumatic stress disorder: an example using the PTSD checklist. J Trauma Stress 2008; 21: 290-300. 19. Greenberg N, Langston V, Jones N: Trauma risk management (TRiM) in the UK Armed Forces. J R Army Med Corps 2008; 154: 124-7. 20.- Greenberg N, Langston V, Everitt B, et al: A cluster randomized controlled trial to determine the efficacy of Trauma Risk Management (TRiM) in a military population. J Trauma Stress 2010; 23: 430-6. 21. Sutherland AG, Johnston AT, Hutchison ID. The new injury severity score: better prediction of functional recovery after musculoskeletal injury. Value Health 2006; 9: 24-7.

MILITARY MEDICINE, Vol. 178, November 2013

Copyright of Military Medicine is the property of Association of Military Surgeons of the United States and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.

The injury burden of recent combat operations: mortality, morbidity, and return to service of U.K. naval service personnel following combat trauma.

The study establishes the functional outcomes of service personnel injured in current conflicts by correlating data on initial injury to the findings ...
508KB Sizes 0 Downloads 0 Views