Analysis of Surgical Volume in Military Medical Treatment Facilities and Clinical Combat Readiness of US Military Surgeons

Key Points

Question  Have there been changes in surgical case volumes for US military general surgeons as measured by the Knowledge, Skills, and Abilities (KSA) metric, which was designed to quantify the clinical readiness value of surgical workload?

Findings  In this cohort study including 147 medical treatment facilities and military medical units, the number of general surgery procedures generating KSAs in military hospitals decreased 25% from fiscal year 2015 to 2019, with a 19% decrease in the number of general surgeons’ KSA points. The proportion of military general surgeons meeting the KSA metric readiness threshold decreased from about 17% in 2015 to about 10% in 2019.

Meaning  The findings of this study suggest that loss of surgical workload has resulted in further decreases in military surgeon readiness and may require substantial changes in patient care flow in the US Military Health System to reverse the change.

Importance  Low surgical volume in the US Military Health System (MHS) has been identified as a challenge to military surgeon readiness. The Uniformed Services University of Health Sciences, in partnership with the American College of Surgeons, developed the Knowledge, Skills, and Abilities (KSA) Clinical Readiness Program that includes a tool for quantifying the clinical readiness value of surgeon workload, known as the KSA metric.

Objective  To describe changes in US military general surgeon procedural volume and readiness using the KSA metric.

Design, Setting, and Participants  This cohort study analyzed general surgery workload performed across the MHS, including military and civilian facilities, between fiscal year 2015 and 2019 and the calculated KSA metric value. The surgeon-level readiness among military general surgeons was calculated based on the KSA metric readiness threshold. Data were obtained from TRICARE, the US Department of Defense health insurance product.

Main Outcomes and Measures  The main outcomes were general surgery procedural volumes and the KSA metric point value of those procedures across the MHS as well as the number of military general surgeons meeting the KSA metric readiness threshold. Aggregate facility and regional market-level claims data were used to calculate the procedural volumes and KSA metric readiness value of those procedures. Annual adjusted KSA metric points earned were used to determine the number of individual US military general surgeons meeting the readiness threshold.

Results  The number of general surgery procedures generating KSAs in military hospitals decreased 25.6%, from 128 377 in 2015 to 95 461 in 2019, with a 19.1% decrease in the number of general surgeon KSA points (from 7 155 563 to 5 790 001). From 2015 to 2019, there was a 3.2% increase in both the number of procedures (from 419 980 to 433 495) and KSA points (from 21 071 033 to 21 748 984) in civilian care settings. The proportion of military general surgeons meeting the KSA metric readiness threshold decreased from 16.7% (n = 97) in 2015 to 10.1% (n = 68) in 2019.

Conclusions and Relevance  This study noted that the number of KSA metric points and procedural volume in military hospitals has been decreasing since 2015, whereas both measures have increased in civilian facilities. The findings suggest that loss of surgical workload has resulted in further decreases in military surgeon readiness and may require substantial changes in patient care flow in the MHS to reverse the change.

As the intensity of fighting in current conflicts has declined, military surgeons are getting less experience treating combat casualties, leading to concerns about the state of the military trauma system and the readiness of military surgeons. This concern has been noted in the popular press, leading to headlines such as “Military Health System Isn’t Ready for Battlefield Injuries.”¹

Throughout modern history, combat casualty care improves during periods of armed conflict only to see these advances diminish in peacetime,^2,3 a phenomenon known as the peacetime effect⁴ or Walker dip.⁵ To counteract this decline, the US Military Health System (MHS) pursues a dual mission of providing a “medically ready force and ready medical force.”^6(p6)7,8 In fulfilment of this mission, care provided in military-owned and -operated hospitals, known as military medical treatment facilities (MTFs), serves not only to promote the health and wellness of service members, but also to ensure the clinical readiness of military health care professionals to provide care in both the MTF and deployed settings.

It has been reported that surgeon operative volume in the civilian population affects clinical outcomes.^9,10 Edwards et al^11,12 have previously reported that US Army general surgeons have operative volumes far below those of their civilian counterparts. Furthermore, over the past 15 years, there has been an overall decrease in the number of select major operations performed in military hospitals.¹³ These decreases have raised concerns that the lack of high-risk procedures taking place at MTFs may negatively affect the ability of military surgeons to maintain clinical readiness.¹⁴ Even in the deployed setting, military surgeons have been performing fewer operations in recent years.^15,16 Decreasing numbers of surgical procedures in MTFs and questions about the effects on clinical combat readiness have also been presented in the popular media.^1,17-19 However, these deficits have not been described empirically in terms of the decreased clinical readiness using validated metrics.

To promote the ongoing readiness of military surgeons, the Uniformed Services University of Health Sciences, in partnership with the American College of Surgeons through the MHS Strategic Partnership American College of Surgeons, created the Knowledge, Skills, and Abilities (KSA) Clinical Readiness Program (CRP). As its name implies, the KSA CRP identified the KSAs relevant to the expeditionary health care professional.²⁰ Although most military surgeons care for few, if any, trauma patients within MTFs,²¹ surgical procedures performed in the nontrauma setting require many similar elements of patient management and operative skills that can be translated to the care of injured patients in the deployed setting.²² Thus, the KSA CRP developed the KSA metric to quantify the MTF-based surgical workload and set a threshold that surgeons should meet in the context of the skill set required of surgeons in the deployed setting.²³ This KSA metric thus provides a means to quantify deficits in clinical readiness and develop realistic and tailored solutions to address these gaps.

In this study, we describe the changes in KSA metric points and the procedural volume on which they are based in MTFs as well as for individuals enrolled in TRICARE, the health insurance product for the US Department of Defense, who receive surgical care in civilian hospitals. In addition, we report changes in the number and proportions of military general surgeons who met the KSA metric readiness threshold.

In partnership with the American College of Surgeons, the military surgical community established a list of 487 unique KSAs relevant to general surgeons in the deployed setting. More than 2000 Current Procedural Terminology codes representing relevant procedures performed by general surgeons, including select evaluation and management codes, were mapped to a set of 49 distinct groups of related and similar procedures, with each group tied to an anchor Current Procedural Terminology code. Each anchor code has an assigned KSA value that represents the importance and relevance to the skill set required of a deployed expeditionary surgeon for that group of similar procedures. This value was determined by identifying the number and frequency of the individual KSAs obtained in performing each step of the procedure, as well as the preoperative and postoperative care of the patients. For general surgeons, procedures were categorized as either high acuity or low acuity depending on the KSA value of the procedure.

A KSA point–based readiness threshold was also established as part of the KSA metric. For general surgeons, this threshold was set at the 75th percentile of surgical volume, translated into KSA points performed by deployed forward surgical teams during the busiest year (2011) of the recent conflicts. For general surgeons, the KSA metric points earned from low-acuity procedures are capped at one-half of this threshold and are adjusted based on procedural diversity. The adjusted KSA metric points earned over a 12-month period can then be compared against the readiness threshold. Detailed descriptions of the US Department of Defense clinical readiness program and the KSA metric have been previously published.²³

This cohort study was deemed exempt from full review with a waiver of informed consent by the Partners HealthCare Human Research Committee. This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.

In addition to active-duty service members of the US military, TRICARE covers non–active-duty personnel, including dependents and retirees. TRICARE beneficiaries receive care in 2 parallel systems. The first is a system of Department of Defense–owned and –operated MTFs, termed direct care. In these facilities, patients are treated by military health care professionals. Alternatively, patients may seek care from civilian hospitals and health care professionals, with TRICARE functioning as a fee-for-service health insurance product. This care provided by nonmilitary physicians in the civilian sector is known as purchased care. TRICARE has also established and defined specific geographic purchased-care markets. Detailed descriptions of the MHS have been published.⁶

TRICARE claims from both direct and purchased care were obtained from the MHS Management Analysis and Reporting Tool database. Procedures were identified in these data through Current Procedural Terminology coding, and surgeons were identified through Health Insurance Portability and Accountability Act taxonomy codes as well as by their military service branch. Procedures were attributed to the military medical unit of the performing surgeon within MTFs.

To better quantify procedural shifts from direct to purchased care and to identify opportunities for recapture of procedures from purchased care back to MTFs, we also examined a subgroup of purchased-care markets we termed surgical markets. We defined these surgical markets as the TRICARE purchased-care markets in which a surgical MTF was located. Surgical MTFs were defined as MTFs that performed at least 1 high-acuity KSA procedure (ie, a major operation) in fiscal year 2019, indicating that the facility has the current capacity to complete a major operation.

The MHS Management Analysis and Reporting Tool was queried for all general surgery KSA point-generating procedures between fiscal years 2015 and 2019. The number of KSA points, procedures, and encounters was identified for each MTF, for all TRICARE beneficiaries who were treated in the purchased-care setting nationwide, and the subset of TRICARE beneficiaries receiving surgical care in purchased-care surgical markets. Relative change over time was defined as the difference between 2015 and 2019 values expressed as a percentage of the 2015 value. The number of KSA point-generating procedures coded per patient encounter was also calculated in an effort to identify coding differences between MTFS and purchased-care health care professionals. The annual adjusted KSA points for surgeons were also calculated to determine the number of surgeons meeting the readiness threshold. Statistical analysis was performed using Excel, version 16.5 (Microsoft Corp).

We identified a total of 147 MTFs and military medical units that generated any general surgery KSA points between fiscal years 2015 and 2019. Of these, 83 MTFs or medical units across 37 markets were classified as a surgical MTF.

The number of general surgery KSA point-generating procedures in MTFs decreased 25.6% from 128 377 in 2015 to 95 461 in 2019 (Table 1). There was a corresponding 19.1% reduction in the number of general surgery KSA points generated in MTFs, from 7 155 563 in 2015 to 5 790 001 in 2019. Meanwhile, there was a 3.2% increase in both the number of procedures (2015: 419 980 to 2019: 433 495) and KSA points (2015: 21 071 033 to 2019: 21 748 984) in the purchased-care environment. The mean number of procedures coded per encounter was similar between MTFs (1.11) and purchased-care hospitals (1.10), indicating similar coding practices between military and nonmilitary health care professionals in the MHS Management Analysis and Reporting Tool data.

High-acuity KSA points constituted most KSA points in both MTFs and purchased care and showed a small increase in the share of KSA points in MTFs between 2015 (64.8%) and 2019 (70.7%) (Figure 1). The number of high-acuity KSA procedures in MTFs decreased during the study period from 42 550 to 37 866. The most common high-acuity procedures performed in MTFs in 2019 were intra-abdominal laparoscopic (n = 6951), breast (n = 4410), and abdominal wall (n = 3705) procedures (Table 2).

In surgical MTFs, the total number of KSA points earned from 2015 to 2019 decreased 16.9% (2015: 6 966 859; 2019: 5 789 600), while procedural volume decreased 24.0% (2015: 125 533; 2019: 95 435) (Figure 2). There was a 6.0% increase in the number of KSA points (2015: 6 570 844; 2019: 6 963 823) and procedures (2015: 144 969; 2019: 153 672) in purchased care in the TRICARE markets with a surgical MTF.

Between 2015 and 2019, the number of US military general surgeons meeting the KSA metric readiness threshold decreased from 97 to 68. This change represented a decrease in the proportion of general surgeons meeting the threshold from 16.7% to 10.1% of all military general surgeons earning any KSA points in that fiscal year (Figure 3).

Changing patterns of care for TRICARE beneficiaries led to a substantial decline between 2015 and 2019 in procedural volume and clinical readiness opportunities for military general surgeons in the MHS, as measured by the novel KSA metric. Already at a low level, the decrease in procedural volume led to a precipitous decrease in the number and percentage of general surgeons reaching the KSA readiness threshold. Although there have been increases in the number of procedures and KSA points in the purchased-care environment, these increases have not been large enough to fully account for the loss of procedures in MTFs.

When patients leave MTF-based care for civilian purchased care, there is a dual cost. First is the lost clinical readiness value to military medical professionals who do not have the opportunity to gain experience from treating those patients. The comparison of changes in KSA point volume in MTFs to the purchased-care environment is relevant because of its implications for patient and procedure recapture. At a time when KSA point-generating procedures are decreasing in MTFs, there are increases in both surgical purchased-care markets and in purchased care systemwide. With the shrinking pool of KSA point-generating procedures across the entire MHS and the already low number of surgeons meeting the KSA metric readiness threshold, recapture efforts must go beyond reversing the current leak of patients from direct to purchased care. To fulfill the dual-readiness mission of the MHS, institution of policies that lead to increasing the volume of procedures to levels not seen in the past 5 years may be required, which may necessitate decreasing the use of purchased care, especially in markets that include surgical MTFs.

Second, in addition to the lost readiness value, there are financial costs associated with increased use of purchased care. Currently, purchased care represents the largest share of Department of Defense health care spending and is growing rapidly.^6,24 This dual cost from the movement of patients to purchased care has made recapture a priority for the Defense Health Agency. The KSA metric provides a new way to quantify the readiness value of care that will allow it to be better represented and balanced against quality metrics and financial costs in efforts to improve the MHS. There are also opportunities to improve clinical readiness and increase KSA point volumes by optimizing MTF operations. This is of particular importance, given our findings of decreases in total procedural and KSA point volumes in MTFs that are not fully accounted for by increases in purchased care in surgical markets. The readiness mission of the MHS has traditionally focused on providing MTF-based care to active-duty service members, even to the potential detriment of military health care professionals’ clinical readiness. The ability to quantify the value of procedures toward clinical readiness provides an opportunity to reorganize limited MTF resources in a way that balances the dual-readiness mission of the MHS. For example, the KSA point value of procedures can be used to optimize scheduling for elective operations across specialties and assign priority to cases with more dual-readiness value when operating room capacity is limited. By measuring what matters, the MHS can focus on enhancing its value to provide clinical readiness to combat casualty care medical personnel.

In addition to bringing additional KSA-generating procedures into MTFs, military-civilian partnerships offer an opportunity to improve military clinician readiness by allowing military clinicians to practice in civilian medical centers. In these partnership programs, military surgeons are able to treat a greater volume of patients with high-acuity conditions than are available at most MTFs. Military-civilian partnerships have been successfully implemented at several of the busiest trauma centers in the US, including the Ryder Trauma Center, R Adams Cowley Shock Trauma Center, and Los Angeles County + University of Southern California Trauma Center, among many others. In furthering the goal of developing these programs across the US, the MHS Strategic Partnership American College of Surgeons has published a best practices guide for creating and sustaining military-civilian partnerships known as The Blue Book.²⁵ The KSA metric, which is easy to measure using existing clinical coding practices, will also be used in the continued development of military-civilian partnerships and has been included in the latest version of The Blue Book. Increasing military surgeon participation in military-civilian partnerships, especially in models in which entire military care teams (including physicians from multiple specialties, nurses, allied health professionals, and others) work together, may reduce the need for increasing surgical volumes at MTFs from a surgeon readiness perspective.

In addition to these military-civilian partnerships, opening MTF care to non-TRICARE beneficiaries for high-KSA value patient encounters presents an opportunity to improve clinical readiness. Examples of this model are in use at the trauma centers of Brooke Army Medical Center and Naval Medical Center Camp Lejeune, which care for both injured military and civilian patients in their regions.

One of the key features of the TRICARE program is the bifurcated system that provides care to beneficiaries in both military and civilian hospital settings—a choice that is important to beneficiaries. Policies designed to improve retention within the direct care system should ensure that military hospitals provide high-quality patient care and patient experience, spurring patients to choose these hospitals for their surgical care. Recent work has noted that several MTFs perform in the top tier nationally with respect to surgical quality and safety, and statistical trends toward systemwide improvement have been noted since the implementation of the American College of Surgeons National Surgical Quality Improvement Program in the MHS.²⁶ Policy makers must be conscious of the association between quality and low-volume procedures. One potential strategy would be to cluster surgical subspecialists at specific MTFs to increase the volume of specific procedures at designated MTFs and directing patients needing these procedures to civilian care in other markets. In addition, the expansion of regional multidisciplinary centers of excellence, such as the Murtha Cancer Center at Walter Reed National Military Medical Center, might help to address the issue of low-volume procedures.

Although many of the anchor procedures, such as vascular and burn surgeries, have an obvious association with combat readiness, the readiness value of other procedure types may be less obvious. The high KSA value of breast surgery, one of the most commonly performed operations in MTFs, is derived from the military surgeon’s need to be able to manage soft-tissue injuries, which are among the most common combat injuries. In addition, abdominal wall and hernia surgery, another higher-volume procedure, has significant combat readiness ties in the management of damage control surgery and eventual abdominal closure.

In this study, we focused on the KSA metric component of the CRP for military general surgeons. However, in addition to general surgery, the Department of Surgery at the Uniformed Services University has developed these metrics for most surgical specialties in addition to emergency medicine and critical care. The ultimate goal is to have metrics by which to measure clinical readiness for all physicians and surgeons across the spectrum involved in combat casualty care and to include critical care and emergency medicine nursing and the enlisted specialties involved in prehospital care, the operating room, and the intensive care unit. The KSA program also links the metrics of readiness with knowledge and skills assessments to fill the critical gap between usual practice and deployed clinical requirements. This includes specialty-specific skills assessments, such as the military-enhanced version of the American College of Surgeons’ Advanced Surgical Skills for Exposure in Trauma course, which are used to bridge gaps in knowledge and skills.

Although the KSA CRP metric was designed for the expeditionary surgeon, the underlying methods represent an opportunity to improve on the way clinical competency is assessed in the civilian setting. A competency-based model for medical training and certification has already been implemented by accrediting bodies in the US and other countries.^27,28 In addition, data on clinical activity are presently collected in the form of case logs for trainees in both surgical²⁹ and nonsurgical³⁰ programs. In this setting, a similarly constructed metric tool that is tailored to the global competencies and specific KSAs relevant to clinicians in a particular specialty could more robustly evaluate readiness for independent practice than the present volume-based assessments.^31,32

The KSA CRP is nested within the Defense Health Agency under the assistant director for combat support. The KSA metrics are used by leaders at this level to support decisions that can improve efforts to recapture surgical and other workload to improve clinical readiness of the entire combat casualty care team.

The findings of this study should be interpreted in the context of its limitations. The procedural volume of military surgeons is limited to what is coded in the MHS Management Analysis and Reporting Tool data. These data do not capture any caseload performed by military surgeons outside of MTFs, including off-duty employment in civilian hospitals or work done as part of civilian-military collaboratives in civilian hospitals. Similarly, these data do not include the work of surgeons serving in the reserves that occurs outside the MHS. Efforts are in progress to be able to capture this component of workload. In addition, some surgeons may have been inactive in the MHS for a time during a fiscal year, which is also not accounted for by the MHS Management Analysis and Reporting Tool data. It is possible that there are coding differences between MTFs and civilian hospitals, although the use of anchor Current Procedural Terminology–based calculations may minimize this limitation. In addition, the number of procedures per encounter was similar between MTFs and purchased care. Future studies that are able to quantify civilian general surgeon workload using the KSA metric may help to provide additional context to the previously identified surgeon operative volume gap^11,12 between military and civilian surgeons in improving military surgeon readiness.

Following shifts of increased access to civilian health care professionals, the number of surgical procedures and corresponding KSA metric points in MTFs has been decreasing in recent years, resulting in decreasing readiness among military general surgeons. Ongoing efforts to align patient flow and resource allocation in the MHS that balance access to civilian care with the necessary readiness mission of the MHS may be useful.

Accepted for Publication: August 13, 2021.

Published Online: October 27, 2021. doi:10.1001/jamasurg.2021.5331

Correction: This article was corrected on November 17, 2021, to fix a typographical error in the Methods section.

Corresponding Author: Michael K. Dalton, MD, MPH, Center for Surgery and Public Health, Harvard Medical School, Harvard T. H. Chan School of Public Health, Department of Surgery, Brigham and Women’s Hospital, 1620 Tremont St, Boston, MA 02110 (md1613@njms.rutgers.edu).

Author Contributions: Dr Dalton and Mr Mathias had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Dalton, Remick, Trinh, Elster, Weissman.

Acquisition, analysis, or interpretation of data: Dalton, Mathias, Trinh, Cooper, Weissman.

Drafting of the manuscript: Dalton, Remick, Mathias.

Critical revision of the manuscript for important intellectual content: Mathias, Trinh, Cooper, Elster, Weissman.

Statistical analysis: Dalton, Mathias.

Administrative, technical, or material support: Elster, Weissman.

Supervision: Remick, Trinh, Cooper, Elster, Weissman.

Conflict of Interest Disclosures: Dr Trinh reported receiving honoraria from Astellas, Bayer, and Janssen, and grants from Pfizer outside the submitted work. No other disclosures were reported.

Funding/Support: This study was funded through grant HU0001-11-1-0023 from the US Department of Defense, Defense Health Agency (Drs Dalton, Trinh, and Weissman Cooper). Mr Mathias also received funding through contract HT001119C0018 from the US Department of Defense, Defense Health Agency.

Role of the Funder/Sponsor: The funding organizations had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Disclaimer: The opinions or assertions contained herein are the private ones of the authors and are not to be construed as official or reflecting the views of the Department of Defense, the Uniformed Services University of the Health Sciences, or any other agency of the US government.

Additional Contributions: Tim Small, MBA, Megan Kolodgy, MPH, MHSA, Jonathan Jaffin, MD, Stephen McIntyre, PhD, MS, Ricardo Celleri, BA, and Jenna Vandervort, BS (Deloitte Consulting LLP), contributed to the Knowledge, Skills, and Abilities method and this analysis. No financial compensation outside of salary was provided.