0
Scientific Articles   |    
The Prevalence of and Specific Risk Factors for Venous Thromboembolic Disease Following Elective Spine Surgery
Jason M. Sansone, MD1; Alejandro Munoz del Rio, PhD1; Paul A. Anderson, MD1
1 Department of Orthopedics and Rehabilitation, University of Wisconsin, K4/738 Clinical Science Center, 600 Highland Avenue, Madison, WI 53792. E-mail address for P.A. Anderson: anderson@orthorehab.wisc.edu
View Disclosures and Other Information
Disclosure: The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity.

A commentary by Michael F. Schafer, MD, is available at www.jbjs.org/commentary and as supplemental material to the online version of this article.
Investigation performed at the Department of Orthopedics and Rehabilitation, University of Wisconsin at Madison, Madison, Wisconsin

Copyright ©2010 American Society for Journal of Bone and Joint Surgery, Inc.
J Bone Joint Surg Am, 2010 Feb 01;92(2):304-313. doi: 10.2106/JBJS.H.01815
5 Recommendations (Recommend) | 3 Comments | Saved by 3 Users Save Case

Abstract

Background: 

Venous thromboembolic disease, including deep venous thrombosis and pulmonary embolism, is a serious and potentially life-threatening complication following orthopaedic surgical procedures. We sought to investigate the prevalence of thromboembolism as well as the efficacy and complications of various prophylactic measures in a population of patients who had undergone elective spine surgery.

Methods: 

A meta-analysis and univariate logistic regression were performed on selected studies to determine the prevalence of and risk factors for deep venous thrombosis and pulmonary embolism following elective spine surgery. Studies were included on the basis of the selection criteria (specifically, the inclusion of only patients undergoing spine surgery, or the treatment of patients undergoing spine surgery as an independent cohort; the use of an objective diagnostic modality for the diagnosis of deep venous thrombosis, including Doppler ultrasonography or venography; the use of an objective diagnostic modality for the diagnosis of pulmonary embolism, including computed tomography of the chest or a ventilation-perfusion scan; and a study population of more than thirty patients). Patients with a known spinal cord injury were excluded.

Results: 

Fourteen studies (including a total of 4383 patients) met our selection criteria. On the basis of the meta-analysis, the prevalence of deep venous thrombosis was 1.09% (95% confidence interval, 0.54% to 1.64%) and the prevalence of pulmonary embolism was 0.06% (95% confidence interval, 0.01% to 0.12%) following elective spine surgery. The use of pharmacologic prophylaxis significantly reduced the prevalence of deep venous thrombosis relative to either mechanical prophylaxis (p = 0.047) or no prophylaxis (p < 0.01). One fatal pulmonary embolism was reported. An epidural hematoma requiring surgical evacuation was reported in eight of 2071 patients receiving pharmacologic prophylaxis; three of these patients had a permanent neurologic deficit.

Conclusions: 

The risk of deep venous thrombosis and pulmonary embolism is relatively low following elective spine surgery, particularly for patients who receive pharmacologic prophylaxis. Unfortunately, pharmacologic prophylaxis exposes patients to a greater risk of epidural hematoma. More evidence is needed prior to establishing a protocol for prophylaxis against venous thromboembolic disease in patients undergoing elective spine surgery. Future prospective studies should seek to define the safety of various prophylactic modalities and to identify specific subpopulations of patients who are at greater risk for venous thromboembolism.

Level of Evidence: 

Therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence.

Figures in this Article
    Sign In to Your Personal ProfileSign In To Access Full Content
    Not a Subscriber?
    Get online access for 30 days for $35
    New to JBJS?
    Sign up for a full subscription to both the print and online editions
    Register for a FREE limited account to get full access to all CME activities, to comment on public articles, or to sign up for alerts.
    Register for a FREE limited account to get full access to all CME activities
    Have a subscription to the print edition?
    Current subscribers to The Journal of Bone & Joint Surgery in either the print or quarterly DVD formats receive free online access to JBJS.org.
    Forgot your password?
    Enter your username and email address. We'll send you a reminder to the email address on record.

     
    Forgot your username or need assistance? Please contact customer service at subs@jbjs.org. If your access is provided
    by your institution, please contact you librarian or administrator for username and password information. Institutional
    administrators, to reset your institution's master username or password, please contact subs@jbjs.org

    References

    Accreditation Statement
    These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.
    CME Activities Associated with This Article
    Submit a Comment
    Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
    Comments are moderated and will appear on the site at the discretion of JBJS editorial staff.

    * = Required Field
    (if multiple authors, separate names by comma)
    Example: John Doe





    Paul A. Anderson, MD
    Posted on April 28, 2010
    Drs. Anderson and Sansone respond to Dr. Hohl and colleagues
    University of Wisconsin, Madison, Wisconsin

    We thank Dr. Hohl and colleagues for submitting a Letter to the Editor, in which they raise interesting questions with regard to our recent publication entitled “The Prevalence of and Specific Risk Factors for Venous Thromboembolic Disease Following Elective Spine Surgery.” Specifically, the group is concerned that the meta-analysis underestimates the true incidence of pulmonary embolism (PE) in the subset of patients undergoing thoracolumbar spine surgery.

    They present a calculation of the incidence of pulmonary embolism (PE) based upon three of the fourteen studies included in the meta-analysis (1-3). By their calculation, averaging these data yields an incidence of PE of 1.5% for patients undergoing thoracolumbar spine surgery. This excludes the study by Gerlach et al., which we included in our meta-analysis (4). The authors argue that due to its large patient population and zero incidence of PE, it skews the data in a negative direction, leading us to inaccurately report an incidence of 0.2% in the this same population.

    We performed sensitivity analyses by excluding the Gerlach study and reported the incidence of PE with and without that study ranging from 0.06% to 0.27% (4.5-fold increase). We did not, however, perform a similar computation for the thoracolumbar spine surgery sub-group. This would have yielded a six-fold higher incidence of PE (1.3%, 5/391) in this group. The authors of the recent letter found an incidence of 1.5% but failed to exclude patients from Dearborn et al., which did not report a specific diagnosis, whereas we excluded such patients in an attempt to limit the data to elective surgery patients.

    Regardless of the calculation, a few salient points need to be reiterated. The intended conclusion of our recent publication was not to report specific numbers, for as we mention, a meta-analysis is highly susceptible to “interstudy variability and the differential influence of specific studies” and thus should not be used to provide exact data. Rather, based upon our analysis, one can summarily state that the incidence of PE is low in elective spine surgery patients, and that the potential consequences of pharmacologic prophylaxis may not warrant its routine administration.

    We discuss in our paper that the elective spine surgery population is highly diverse in terms of patient diagnosis, operative level and extent of procedure. Although we and other authors note a trend toward greater risk of venous thromboembolism in thoracolumbar surgery, and certainly combined anterior/posterior arthrodesis, the current body of published data is too small and variable to establish any definitive conclusions.

    We would like to reemphasize that, at a time when standards of care and pay for performance are a growing trend in medicine, simply extrapolating current practices in other areas such as trauma and joint arthroplasty (with regard to venous thromboembolism prophylaxis) to spine surgery is potentially dangerous. Clearly, more investigation is needed on this subject as it applies to the elective spine surgery population. We hope that our publication, in addition to the debates that follow, will spur further research and help shape current and future practice.

    References

    1. Dearborn JT, Hu SS, Tribus CB, Bradford DS. Thromboembolic complications after major thoracolumbar spine surgery. Spine (Phila Pa 1976). 1999;24:1471-6.

    2. Epstein NE. Efficacy of pneumatic compression stocking prophylaxis in the prevention of deep venous thrombosis and pulmonary embolism following 139 lumbar laminectomies with instrumented fusions. J Spinal Disord Tech. 2006;19:28-31.

    3. Wood KB, Kos PB, Abnet JK, Ista C. Prevention of deep-vein thrombosis after major spinal surgery: a comparison study of external devices. J Spinal Disord. 1997;10:209-14.

    4. Gerlach R, Raabe A, Beck J, Woszczyk A, Seifert V. Postoperative nadroparin administration for prophylaxis of thromboembolic events is not associated with an increased risk of hemorrhage after spinal surgery. Eur Spine J. 2004;13:9-13.

    Justin B. Hohl, MD
    Posted on March 19, 2010
    The Prevalence of PE in Degenerative Thoracolumbar Spine Surgery
    University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania

    To the Editor:

    A recent meta-analysis (1) evaluated the prevalence of thromboembolic disease following elective spine surgery and the authors are to be congratulated for addressing this important topic. This study reviewed 14 studies (including 4383 patients) and reported that the prevalence of deep venous thrombosis (DVT) was 1.09%, while the prevalence of pulmonary embolism (PE) was 0.06%. The prevalence of PE was reported as 0.4% (three of 840) in cervical cases and 0.2% (five of 2838) for patients undergoing thoracolumbar procedures.

    We are concerned that this meta-analysis may under-represent the true prevalence of pulmonary embolism, specifically in the subset of patients undergoing thoracolumbar spine surgery. Of the 14 studies that were evaluated by Sansone and colleagues, only 4 of these studies had a separate analysis of the prevalence of PE in thoracolumbar surgery alone (2-5). Of these, the study by Gerlach and colleagues (4) reported on the prevalence of PE in patients treated prophylactically with low molecular weight heparin (nadroparin), while the other three studies (2,3,5) used mechanical prophylaxis including compression stockings and pneumatic compression devices.

    We reviewed the three studies that addressed thoracolumbar surgery with mechanical prophylaxis alone, excluding the Gerlach study because it evaluated chemical prophylaxis and cannot be fairly compared to studies using mechanical prophylaxis. Of note, each of these investigations excluded discectomies. The prevalence of pulmonary embolism in each of these studies is as follows: Dearborn and colleagues (2), 2.2% (7/318), Wood and colleagues (5), 0.74% (1/136), and Epstein and colleagues (3), 0.72% (1/139). Combining the patients in these studies yields a prevalence of 1.5% (9/593) for thoracolumbar spine surgery, which is more than seven-fold higher than the prevalence of 0.2% (five of 2838) reported by Sansone and colleagues for thoracolumbar spine surgery. Additionally, the Dearborn and Wood papers used ventilation perfusion scans, which are less sensitive than CT scans in detecting PE’s (6,7).

    Although the method for arriving at this prevalence of 0.2% is not explained in Sansone’s report, it is possible that it is this low because they included the patients from Gerlach’s study who had chemical prophylaxis and other studies that included discectomies, both of which would likely result in a lower prevalence. Nonetheless, no mention is made of this issue, and the conclusion is that the risk of PE is low in thoracolumbar surgery. We would propose that, in the subgroup of patients undergoing thoracolumbar decompression and fusion that involves more than a discectomy, the prevalence of pulmonary embolism is higher. The consequences of under-representing the prevalence of PE in this population are unknown but may hinder additional research that evaluates the potential role of thromboembolic prophylaxis in patients undergoing thoracolumbar spine surgery.

    The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity.

    References

    1. Sansone JM, del Rio AM, Anderson PA. The prevalence of and specific risk factors for venous thromboembolic disease following elective spine surgery. J Bone Joint Surg Am. 2010;92:304-13.

    2. Dearborn JT, Hu SS, Tribus CB, Bradford DS. Thromboembolic complications after major thoracolumbar spine surgery. Spine (Phila Pa 1976). 1999;24:1471-6.

    3. Epstein NE. Efficacy of pneumatic compression stocking prophylaxis in the prevention of deep venous thrombosis and pulmonary embolism following 139 lumbar laminectomies with instrumented fusions. J Spinal Disord Tech. 2006;19:28-31.

    4. Gerlach R, Raabe A, Beck J, Woszczyk A, Seifert V. Postoperative nadroparin administration for prophylaxis of thromboembolic events is not associated with an increased risk of hemorrhage after spinal surgery. Eur Spine J. 2004;13:9-13.

    5. Wood KB, Kos PB, Abnet JK, Ista C. Prevention of deep-vein thrombosis after major spinal surgery: a comparison study of external devices. J Spinal Disord. 1997;10:209-14.

    6. Blachere H, Latrabe V, Montaudon M, Valli N, Couffinhal T, Raherisson C, Leccia F, Laurent F. Pulmonary embolism revealed on helical CT angiography: comparison with ventilation-perfusion radionuclide lung scanning. AJR Am J Roentgenol. 2000;174:1041-7.

    7. Coche E, Verschuren F, Keyeux A, Goffette P, Goncette L, Hainaut P, Hammer F, Lavenne E, Zech F, Meert P, Reynaert MS. Diagnosis of acute pulmonary embolism in outpatients: comparison of thin-collimation multi-detector row spiral CT and planar ventilation-perfusion scintigraphy. Radiology. 2003;229:757-65.

    Related Content
    The Journal of Bone & Joint Surgery
    JBJS Case Connector
    Topic Collections
    Related Audio and Videos
    PubMed Articles
    Guidelines
    Guidelines on use of vena cava filters. -British Committee for Standards in Haematology | 9/25/2009
    Guidelines on the use and monitoring of heparin. -British Committee for Standards in Haematology | 9/25/2009
    Results provided by:
    PubMed
    Clinical Trials
    Readers of This Also Read...
    JBJS Jobs
    11/15/2013
    Louisiana - Ochsner Health System
    12/31/2013
    S. Carolina - Department of Orthopaedic Surgery Medical Univerity of South Carlonina
    05/03/2012
    California - UCLA/OH Department of Orthopaedic Surgery
    01/22/2014
    Pennsylvania - Penn State Milton S. Hershey Medical Center