Advertisement

Intraoperative consultation of vascular surgeons is increasing at a major American trauma center

      Abstract

      Objective

      Vascular surgeons are often called to aid other surgical specialties for complex exposure, hemorrhage control, or revascularization. The evolving role of the vascular surgeon in the management of intraoperative emergencies involving trauma patients remains undefined. The primary aims of this study included determining the prevalence of intraoperative vascular consultation in trauma, describing how these interactions have changed over time, and characterizing the outcomes achieved by vascular surgeons in these settings. We hypothesized that growing endovascular capabilities of vascular surgeons have resulted in an increased involvement of vascular surgery faculty in the management of the trauma patient over time.

      Methods

      A retrospective review of all operative cases at a single level I trauma center where a vascular surgeon was involved, but not listed as the primary surgeon, between 2002 and 2017 was performed. Cases were abstracted using Horizon Surgical Manager, a documentation system used in our operating room to track staff present, the type of case, and use. All elective cases were excluded.

      Results

      Of the 256 patients initially identified, 22 were excluded owing to the elective or joint nature of the procedure, leaving 234 emergent operative vascular consultations. Over the 15-year study period, a 529% increase in the number of vascular surgery consultations was seen, with 65% (n = 152) being intraoperative consultations requiring an immediate response. Trauma surgery (n = 103 [44%]) and orthopedic surgery (n = 94 [40%]) were the most common consulting specialties, with both demonstrating a trend of increasing consultations over time (general surgery, 1400%; orthopedic surgery, 220%). Indications for consultation were extremity malperfusion, hemorrhage, and concern for arterial injury. The average operative time for the vascular component of the procedures was 2.4 hours. Of patients presenting with ischemia, revascularization was successful in 94% (n = 116). Hemorrhage was controlled in 99% (n = 122). In-hospital mortality was relatively low at 7% (n = 17). Overall, despite the increase in intraoperative vascular consultations over time, a concomitant increase in the proportion of procedures done using endovascular techniques was not seen.

      Conclusions

      Vascular surgeons are essential team members at a level I trauma center. Vascular consultation in this setting is often unplanned and often requires immediate intervention. The number of intraoperative vascular consultations is increasing and cannot be attributed solely to an increase in endovascular hemorrhage control, and instead may reflect the declining experience of trauma surgeons with vascular trauma. When consulted, vascular surgeons are effective in quickly gaining control of the situation to provide exposure, hemorrhage control, or revascularization.

      Graphical abstract

      Keywords

      Article Highlights
      • Type of Research: Single-center retrospective cohort study
      • Key Findings: At a level I trauma center, a 529% increase in vascular surgery consultations was seen over 15 years, with increased consultations seen from trauma (1400% increase) and orthopedic surgery (220% increase). During this period, the proportion of procedures done endovascularly remained unchanged.
      • Take Home Message: The number of intraoperative vascular consultations in trauma is increasing, a trend that is not explained by endovascular capabilities and has been driven largely by increased consultation from trauma surgery.
      The role of the vascular surgeon as the surgeon's consultant providing intraoperative assistance, in both an elective and emergent capacity, is well-defined. Previous studies have characterized the nature of these consultations, highlighting the important role that vascular surgeons play in assisting with exposure, reconstruction, and hemorrhage control in a variety of surgeries, especially oncologic, spine, and orthopedic procedures.
      • Danczyk R.C.
      • Coleman J.
      • Allensworth J.
      • Azarbal A.F.
      • Mitchell E.L.
      • Liem T.K.
      • et al.
      Incidence and outcomes of intraoperative vascular surgery consultations.
      • Leithead C.C.
      • Matthews T.C.
      • Pearce B.J.
      • Novak Z.
      • Patterson M.
      • Passman M.A.
      • et al.
      Analysis of emergency vascular surgery consults within a tertiary health care system.
      • Manzur M.F.
      • Ham S.W.
      • Elsayed R.
      • Abdoli S.
      • Simcox T.
      • Han S.
      • et al.
      Vascular surgery: an essential hospital resource in modern health care.
      • Mogannam A.C.
      • Chavez De Paz C.
      • Sheng N.
      • Patel S.
      • Bianchi C.
      • Chiriano J.
      • et al.
      Early vascular consultation in the setting of oncologic resections: benefit for patients and a continuing source of open vascular surgical training.
      • Parvizi J.
      • Pulido L.
      • Slenker N.
      • Macgibeny M.
      • Purtill J.J.
      • Rothman R.H.
      Vascular injuries after total joint arthroplasty.
      • Tomita T.M.
      • Rodriguez H.E.
      • Hoel A.W.
      • Ho K.J.
      • Pearce W.H.
      • Eskandari M.K.
      Implications of intraoperative vascular surgery assistance for hospitals and vascular surgery trainees.
      • Wilson J.S.
      • Miranda A.
      • Johnson B.L.
      • Shames M.L.
      • Back M.R.
      • Bandyk D.F.
      Vascular injuries associated with elective orthopedic procedures.
      • Yoo T.K.
      • Min S.K.
      • Ahn S.
      • Kim S.Y.
      • Min S.I.
      • Park Y.J.
      • et al.
      Major vascular injury during nonvascular surgeries.
      • Zahradnik V.
      • Lubelski D.
      • Abdullah K.G.
      • Kelso R.
      • Mroz T.
      • Kashyap V.S.
      Vascular injuries during anterior exposure of the thoracolumbar Spine.
      Although planned consultations often occur in the preoperative setting, emergent consultations are common and frequently require immediate vascular intervention.
      • Leithead C.C.
      • Matthews T.C.
      • Pearce B.J.
      • Novak Z.
      • Patterson M.
      • Passman M.A.
      • et al.
      Analysis of emergency vascular surgery consults within a tertiary health care system.
      Although these studies have collectively shown a wide variety in the indications for, timing of, and specialties requesting these consults, few studies have evaluated the role of the vascular surgeon in the management of the trauma patient, and none have looked exclusively at intraoperative vascular consultations in the trauma population. In addition, no studies have attempted to characterize the changing trends in intraoperative vascular consultation over time. It is unclear what role, if any, vascular surgeons play in the management of intraoperative vascular emergencies in trauma.
      The primary aims of this study included determining the incidence of intraoperative vascular surgery consultation in trauma, characterizing how these consultations have changed over time, and defining the outcomes of these emergent intraoperative trauma consultations. We hypothesized that vascular surgeons have become increasingly involved in the management of the trauma patient over the last two decades owing, in part, to increasing endovascular capabilities.

      Methods

      A retrospective review of all the emergent intraoperative vascular consultations at a level I trauma center from 2002 to 2017 was performed. Cases were identified using Horizon Surgical Manager, a documentation system used in our operating room to track staff present, type of surgery performed, and use. All operative cases where a vascular surgeon was involved, but not listed as the primary surgeon, were included, whereas any cases listing vascular surgery as the primary service, all elective cases, and consultations obtained preoperatively, were excluded.
      Specialties requesting consultation, reasons for consultation, interventions performed, and outcomes achieved, including mean operative time for vascular surgery, rate of successful revascularization, rate of hemorrhage control, amputation rate, and mortality, were recorded for each case using direct review of the medical record. Data abstraction was performed by four independent reviewers and compared for consistency. Continuous variables were expressed as median and interquartile range and categorical variables were expressed as percentages. This study was carried out with University of Washington Institutional Review Board approval, and patient consent was waived for this study.

      Results

      Between 2002 and 2017, 256 cases involving vascular surgery as a consulting service were identified. Of these, 22 cases were excluded owing to the elective or joint nature of the procedure, resulting in 234 cases meeting inclusion criteria. Over the 15-year study period, a 529% increase was seen in the number of consultations occurring per year, with 65% (n = 152) requiring an immediate, intraoperative response (Fig 1). Baseline patient demographics are listed in Table I, which shows a 73% male predominance, a mean age of 38 years, and low rates of hypertension (39%), diabetes (29%), and peripheral artery disease (26%).
      Figure thumbnail gr1
      Fig 1Number of intraoperative vascular surgery consultations per year. During the study period, a 529% increase was seen in the number of intraoperative vascular surgery consultations.
      Table IDemographics
      Characteristics%
      Mean age, years38
      Male73
      Obesity47
      Hypertension39
      Diabetes mellitus29
      Current smoker78
      Peripheral arterial disease26
      The majority of consultations were for trauma (n = 189 [81%]), with 14% (n = 32) the result of iatrogenic injuries and 5% (n = 13) related to difficult patient pathology or anatomy. The most common specialties requesting consultation were general/trauma surgery (44%), orthopedic surgery (40%), spine (6%), and neurosurgery (2%), with other specialties requesting consultation, including hand surgery (2%), otolaryngology (2%), urology (1%), gynecology (1%), oral maxillofacial surgery (1%), and plastic surgery (1%) (Fig 2, A). Common indications for consultation included extremity malperfusion (37%), uncontrollable hemorrhage (26%), arterial injury (20%), and assistance with exposure (6%), with rarer indications including inferior vena cava filter placement (5%) and visceral ischemia (3%), among others (3%) (Fig 2, B). The lower extremities were the most commonly involved region (45%), followed by the upper extremities (17%), head and neck (15%), inferior vena cava and iliac veins (14%), and aorta (9%).
      Figure thumbnail gr2
      Fig 2Specialties requesting consultation (A) and reasons for consultation (B). Common specialties requesting consultation were general surgery (44%), orthopedic surgery (40%), spine (6%), and neurosurgery (2%). Other specialties included hand surgery (2%), otolaryngology (2%), urology (1%), gynecology (1%), oral maxillofacial surgery (1%), and plastic surgery (1%). Reasons for consultation included extremity malperfusion (37%), uncontrollable hemorrhage (26%), arterial injury (20%), assistance with exposure (6%), inferior vena cava filter placement (5%), and visceral ischemia (3%), among others (3%).
      Although increases were seen in the number of consultations received per year from both general/trauma surgery and orthopedics, the yearly increase in total consultations received seems to be driven more so by an increase in the number of general/trauma surgery consultations over the study period (Fig 3). Over the 15-year study period, there was a more than 1400% increase in the number of general/trauma surgery consultations received, as compared with an approximate 220% increase in the number of orthopedics consultations. No other services demonstrated a clear trend in the number of consultations requested over time.
      Figure thumbnail gr3
      Fig 3Number of consultations per year by service. Over the 15-year study period, the increase in the total number of consultations obtained is driven primarily by an increase in consultations from general surgery (1400% increase), although the number of consultations from orthopedics also increased as well (220%).
      Operations performed included primary repair with or without patch angioplasty (34%), bypass (17%), diagnostic angiogram without intervention (14%), ligation (8%), assistance with exposure (6%), fasciotomy (6%), endovascular stenting or hemorrhage control (5%), inferior vena cava filter placement (4%), thrombectomy (2%), and amputation (1%), among others (3%) (Fig 4). Throughout the study period, the proportion of consultations addressed using endovascular techniques did not increase with time (Fig 5). Of patients presenting with ischemia, 94% were successfully revascularized, and hemorrhage was controlled in 99% of cases (Table II). Limb salvage was high, with an overall amputation rate of 1.7%, and in-hospital mortality was low, at 7.3%. The mean operative time for the vascular surgery portion was 2.4 hours.
      Figure thumbnail gr4
      Fig 4Interventions performed. The most common interventions performed included primary repair (34%), bypass (17%), and diagnostic angiogram without intervention (14%). Other procedures performed included ligation (8%), assistance with exposure (6%), fasciotomy (6%), endovascular stenting or hemorrhage control (5%), inferior vena cava filter placement (4%), thrombectomy (2%), and amputation (1%), among others (3%).
      Figure thumbnail gr5
      Fig 5Percentage of interventions requiring endovascular techniques. Over the 15-year study period, the percentage of consultations requiring an endovascular intervention did not increase, with no clear trend seen (R2 = 0.02).
      Table IIOutcomes
      Outcome%
      Mean operative time, hours2.4
      Successful revascularization94
      Hemorrhage controlled99
      Amputation rate1.7
      Mortality7.3
      Among the 103 consultations received from general surgery during the study period, 110 vascular operations were performed, which included primary repair (n = 44 [40%]), vessel ligation (n = 14 [12.7%]), intraoperative assessment with or without a diagnostic angiogram (n = 13 [11.8%]), autogenous bypass (n = 11 [10.0%]), endovascular hemorrhage control (n = 6 [5.5%]), fasciotomy (n = 4 [3.6%]), endovascular stenting (n = 3 [2.7%]), prosthetic bypass (n = 2 [1.8%]), and thrombectomy (n = 2 [1.8%]), among others (n = 11 [10.0%]). The reasons for consultation included extremity malperfusion (20%), arterial injuries (25%), and hemorrhage (43%), with 12% being done for other reasons (including inferior vena cava filter placement and visceral ischemia).

      Discussion

      Although previous studies have evaluated the important role that vascular surgeons play as the intraoperative consultant to a variety of specialties, these studies often exclude emergent intraoperative consultations and rarely examine the role of vascular surgeons in the management of trauma patients.
      • Danczyk R.C.
      • Coleman J.
      • Allensworth J.
      • Azarbal A.F.
      • Mitchell E.L.
      • Liem T.K.
      • et al.
      Incidence and outcomes of intraoperative vascular surgery consultations.
      • Leithead C.C.
      • Matthews T.C.
      • Pearce B.J.
      • Novak Z.
      • Patterson M.
      • Passman M.A.
      • et al.
      Analysis of emergency vascular surgery consults within a tertiary health care system.
      • Manzur M.F.
      • Ham S.W.
      • Elsayed R.
      • Abdoli S.
      • Simcox T.
      • Han S.
      • et al.
      Vascular surgery: an essential hospital resource in modern health care.
      • Mogannam A.C.
      • Chavez De Paz C.
      • Sheng N.
      • Patel S.
      • Bianchi C.
      • Chiriano J.
      • et al.
      Early vascular consultation in the setting of oncologic resections: benefit for patients and a continuing source of open vascular surgical training.
      • Parvizi J.
      • Pulido L.
      • Slenker N.
      • Macgibeny M.
      • Purtill J.J.
      • Rothman R.H.
      Vascular injuries after total joint arthroplasty.
      • Tomita T.M.
      • Rodriguez H.E.
      • Hoel A.W.
      • Ho K.J.
      • Pearce W.H.
      • Eskandari M.K.
      Implications of intraoperative vascular surgery assistance for hospitals and vascular surgery trainees.
      • Wilson J.S.
      • Miranda A.
      • Johnson B.L.
      • Shames M.L.
      • Back M.R.
      • Bandyk D.F.
      Vascular injuries associated with elective orthopedic procedures.
      • Yoo T.K.
      • Min S.K.
      • Ahn S.
      • Kim S.Y.
      • Min S.I.
      • Park Y.J.
      • et al.
      Major vascular injury during nonvascular surgeries.
      • Zahradnik V.
      • Lubelski D.
      • Abdullah K.G.
      • Kelso R.
      • Mroz T.
      • Kashyap V.S.
      Vascular injuries during anterior exposure of the thoracolumbar Spine.
      Further, how this role has changed over time, as well as the reasons for any trends, has not been previously explored.
      In the management of the trauma patient at our level I trauma center, vascular surgeons are increasingly being called on as intraoperative consultants to assist with a variety of issues, including ischemia, uncontrolled hemorrhage, and difficult exposures. Vascular surgeons provide effective and efficient care, with low mean operative times and high rates of revascularization and hemorrhage control. Despite this increasing role in trauma, vascular surgeons are not included in the list of specialties that are considered essential in a level I trauma center.
      American Trauma Society
      Trauma center levels explained.
      Although several studies have demonstrated the increasing role of endovascular techniques in the management of various vascular disease processes over the last two decades,
      • Goodney P.P.
      • Travis L.L.
      • Nallamothu B.K.
      • Holman K.
      • Suckow B.
      • Henke P.K.
      • et al.
      Variation in the use of lower extremity vascular procedures for critical limb ischemia.
      ,
      • Suckow B.D.
      • Goodney P.P.
      • Columbo J.A.
      • Kang R.
      • Stone D.H.
      • Sedrakyan A.
      • et al.
      National trends in open surgical, endovascular, and branched-fenestrated endovascular aortic aneurysm repair in Medicare patients.
      endovascular capabilities, and the shifting landscape of a general vascular practice towards an endovascular-heavy approach, cannot entirely explain the trends seen in our study, because the proportion of procedures performed using endovascular techniques remained steady over the 15-year study period (Fig 5). Importantly, the balance between open and endovascular approaches in this study may in part be explained by another trend seen at our institution, in which vascular surgery is increasingly the primary service managing isolated vascular injuries. Our current methodology would not capture these cases, which may involve a greater proportion of endovascular techniques that, when combined with the cases included in the current study, may result in endovascular numbers that are commensurate with the increasing trends seen nationwide. Regardless of the true endovascular case volume, the reasons underlying this shift toward increased vascular involvement in the management of a trauma patient are likely multifactorial, and may be influenced by a decreased trauma surgeon familiarity with vascular repair, as evidenced by multiple studies outlining the decreasing vascular experience of general surgery residents over time.
      • Drake F.T.
      • Horvath K.D.
      • Goldin A.B.
      • Gow K.W.
      The general surgery chief resident operative experience.
      ,
      • Krafcik B.M.
      • Sachs T.E.
      • Farber A.
      • Eslami M.H.
      • Kalish J.A.
      • Shah N.K.
      • et al.
      Assessment of open operative vascular surgical experience among general surgery residents.
      Drake et al,
      • Drake F.T.
      • Horvath K.D.
      • Goldin A.B.
      • Gow K.W.
      The general surgery chief resident operative experience.
      for example, found a 50% decrease in the mean number of vascular procedures performed by chief general surgery residents between 1989 (59.2 procedures) and 2007 (29.6 procedures).
      • Drake F.T.
      • Horvath K.D.
      • Goldin A.B.
      • Gow K.W.
      The general surgery chief resident operative experience.
      Additionally, Krafcik et al
      • Krafcik B.M.
      • Sachs T.E.
      • Farber A.
      • Eslami M.H.
      • Kalish J.A.
      • Shah N.K.
      • et al.
      Assessment of open operative vascular surgical experience among general surgery residents.
      demonstrated significant decreases in the number of multiple vascular surgery procedures performed by general surgery residents between 1999 and 2013, with a greater than 50% decrease seen in the number of carotid endarterectomies, aortoiliac aneurysm repairs, and lower extremity bypasses performed.
      • Krafcik B.M.
      • Sachs T.E.
      • Farber A.
      • Eslami M.H.
      • Kalish J.A.
      • Shah N.K.
      • et al.
      Assessment of open operative vascular surgical experience among general surgery residents.
      This hypothesis is supported by our study's findings that the increasing trend in vascular consultation at our institution is largely driven by an increased number of consultations from general surgery given the 1400% increase seen (Fig 3).
      Regardless of the reason for the increasing numbers of consultations, the changing role of vascular surgeons in the management of trauma patients, and the financial implications of these trends, is important to recognize. As vascular surgeons become increasingly essential team members at a level I trauma center, one may argue that the 24-hour in-house availability of vascular surgeons at a level I trauma center should be mandated, similar to other required specialties such as plastic surgery and oral and maxillofacial surgery.
      American Trauma Society
      Trauma center levels explained.
      Further, the acknowledgement that vascular surgeons play an essential role in managing trauma patients may result in the recognition of previously unappreciated production that may not be adequately captured through traditional relative value units (RVU) analyses.
      In our study of urgent intraoperative consultations requiring an immediate evaluation, more than 50% of consultations involved either a primary repair, with or without vein patch angioplasty, or bypass. According to the Center for Medicare and Medicaid Services 2020 Physician Fee Schedule, these procedures pay $872.29 or 15.30 work RVUs (wRVUs) for primary repair with or without patch angioplasty (Current Procedural Terminology [CPT] code 35226), and $1469.93 or 26.75 wRVUs for a bypass graft with vein (CPT code 35556).
      Center for Medicare and Medicaid Services
      CY 2020 physician fee schedule.
      With these cases averaging 2.2 and 3.9 hours, respectively, these payments resulted in $396.50 per hour or 6.95 wRVUs per hour for a primary repair, and $376.91 per hour or 6.86 wRVUs per hour for a bypass. Despite these estimates not including the substantial time required for postoperative care and outpatient follow-up, they demonstrate the mismatch between the amount of time and energy required for these cases, and the low reimbursements received. In addition, these estimates do not consider the work flow disruptions that occur when these consults are received during daytime hours, or the productivity impacts of disrupted sleep when they are received overnight. If the current trends continue, such that vascular surgeons are increasingly called on for intraoperative assistance with the trauma patient, hospitals will need to address the relatively low reimbursements given for time-consuming work that requires the vascular surgeon to be available immediately at all times.
      Given its retrospective nature, this analysis has several limitations. In addition to those inherent to retrospective reviews, such as the possibility that data reviewed are missing or inaccurate, others include the inability to determine individual surgeon factors driving vascular consultation, as well as the nonmedical factors (medicolegal and systems policy factors) that may influence these trends. Based on the information available, although hypotheses can be made, it is less clear exactly why the trends we are observing exist.
      Looking forward, it will be important to quantify the financial implications of these changing trends in order to demonstrate the value that vascular surgeons bring to a level I trauma center outside of a standard clinical practice. Understanding these financial contributions will ensure that vascular surgeons, and divisions of vascular surgery, are adequately compensated for these currently underappreciated services. Furthermore, understanding individual surgeon factors that drive vascular consultation in trauma may reveal why these trends exist. Ultimately, understanding these trends will allow for level I trauma centers to predict future needs and ensure that adequate vascular coverage is available. Last, determining the medicolegal and policy factors influencing these trends will allow vascular surgeons to impact these changing practice patterns.

      Conclusions

      Vascular surgeons are essential team members in a level I trauma center, with increasing involvement in the management of the trauma patient over time. These trends are not explained by endovascular capabilities, and instead may be explained by decreased trauma surgeon familiarity with vascular repairs, based on the changes in the experience provided by a general surgery residency over time. Despite these trends, vascular surgeons continue to provide timely and effective care.

      Author contributions

      Conception and design: JH, SD, MD, NS, EQ, NT, BS
      Analysis and interpretation: JH, SD, MD, CT, RH, AG, AS, NS, EQ, NT, BS
      Data collection: JH, MD, CT, RH, AG, AS
      Writing the article: JH, SD, MD, CT, RH, AG, AS, NS, EQ, NT, BS
      Critical revision of the article: JH, NS, EQ, NT, BS
      Final approval of the article: JH, SD, MD, CT, RH, AG, AS, NS, EQ, NT, BS
      Statistical analysis: JH
      Obtained funding: Not applicable
      Overall responsibility: BS

      References

        • Danczyk R.C.
        • Coleman J.
        • Allensworth J.
        • Azarbal A.F.
        • Mitchell E.L.
        • Liem T.K.
        • et al.
        Incidence and outcomes of intraoperative vascular surgery consultations.
        J Vasc Surg. 2015; 62: 177-182
        • Leithead C.C.
        • Matthews T.C.
        • Pearce B.J.
        • Novak Z.
        • Patterson M.
        • Passman M.A.
        • et al.
        Analysis of emergency vascular surgery consults within a tertiary health care system.
        J Vasc Surg. 2016; 63: 177-181
        • Manzur M.F.
        • Ham S.W.
        • Elsayed R.
        • Abdoli S.
        • Simcox T.
        • Han S.
        • et al.
        Vascular surgery: an essential hospital resource in modern health care.
        J Vasc Surg. 2017; 65: 1786-1792
        • Mogannam A.C.
        • Chavez De Paz C.
        • Sheng N.
        • Patel S.
        • Bianchi C.
        • Chiriano J.
        • et al.
        Early vascular consultation in the setting of oncologic resections: benefit for patients and a continuing source of open vascular surgical training.
        Ann Vasc Surg. 2015; 29: 810-815
        • Parvizi J.
        • Pulido L.
        • Slenker N.
        • Macgibeny M.
        • Purtill J.J.
        • Rothman R.H.
        Vascular injuries after total joint arthroplasty.
        J Arthroplasty. 2008; 23: 1115-1121
        • Tomita T.M.
        • Rodriguez H.E.
        • Hoel A.W.
        • Ho K.J.
        • Pearce W.H.
        • Eskandari M.K.
        Implications of intraoperative vascular surgery assistance for hospitals and vascular surgery trainees.
        JAMA Surg. 2016; 151: 1032-1038
        • Wilson J.S.
        • Miranda A.
        • Johnson B.L.
        • Shames M.L.
        • Back M.R.
        • Bandyk D.F.
        Vascular injuries associated with elective orthopedic procedures.
        Ann Vasc Surg. 2003; 17: 641-644
        • Yoo T.K.
        • Min S.K.
        • Ahn S.
        • Kim S.Y.
        • Min S.I.
        • Park Y.J.
        • et al.
        Major vascular injury during nonvascular surgeries.
        Ann Vasc Surg. 2012; 26: 825-832
        • Zahradnik V.
        • Lubelski D.
        • Abdullah K.G.
        • Kelso R.
        • Mroz T.
        • Kashyap V.S.
        Vascular injuries during anterior exposure of the thoracolumbar Spine.
        Ann Vasc Surg. 2013; 27: 306-313
        • American Trauma Society
        Trauma center levels explained.
        (Available at:)
        www.amtrauma.org/page/traumalevels
        Date accessed: June 7, 2019
        • Goodney P.P.
        • Travis L.L.
        • Nallamothu B.K.
        • Holman K.
        • Suckow B.
        • Henke P.K.
        • et al.
        Variation in the use of lower extremity vascular procedures for critical limb ischemia.
        Circ Cardiovasc Qual Outcomes. 2012; 5: 94-102
        • Suckow B.D.
        • Goodney P.P.
        • Columbo J.A.
        • Kang R.
        • Stone D.H.
        • Sedrakyan A.
        • et al.
        National trends in open surgical, endovascular, and branched-fenestrated endovascular aortic aneurysm repair in Medicare patients.
        J Vasc Surg. 2018; 67: 1690-1697.e1
        • Drake F.T.
        • Horvath K.D.
        • Goldin A.B.
        • Gow K.W.
        The general surgery chief resident operative experience.
        JAMA Surg. 2013; 148: 841
        • Krafcik B.M.
        • Sachs T.E.
        • Farber A.
        • Eslami M.H.
        • Kalish J.A.
        • Shah N.K.
        • et al.
        Assessment of open operative vascular surgical experience among general surgery residents.
        J Vasc Surg. 2016; 63: 1110-1115
        • Center for Medicare and Medicaid Services
        CY 2020 physician fee schedule.
        (Available at:)