Timing and risks of chemoprophylaxis after spinal surgery: a single-center experience with 6869 consecutive patients

Full access

OBJECTIVE

Venous thromboembolism (VTE) after spinal surgery is a major cause of morbidity, but chemoprophylactic anticoagulation can prevent it. However, there is variability in the timing and use of chemoprophylactic anticoagulation after spine surgery, particularly given surgeons’ concerns for spinal epidural hematomas. The goal of this study was to provide insight into the safety, efficacy, and timing of anticoagulation therapy after spinal surgery.

METHODS

The authors retrospectively examined records from 6869 consecutive spinal surgeries performed in their departments at Northwestern University. Data on patient demographics, surgery, hospital course, timing of chemoprophylaxis, and complications, including deep venous thrombosis (DVT), pulmonary embolism (PE), and spinal epidural hematomas requiring evacuation, were collected. Data from the patients who received chemoprophylaxis (n = 1904) were compared with those of patients who did not (n = 4965). The timing of chemoprophylaxis, the rate of VTEs, and the incidence of spinal epidural hematomas were analyzed.

RESULTS

The chemoprophylaxis group had more risk factors, including greater age (59.70 vs 51.86 years, respectively; p < 0.001), longer surgery (278.59 vs 145.66 minutes, respectively; p < 0.001), higher estimated blood loss (995 vs 448 ml, respectively; p < 0.001), more comorbid diagnoses (2.69 vs 1.89, respectively; p < 0.001), history of VTE (5.8% vs 2.1%, respectively; p < 0.001), and a higher number were undergoing fusion surgery (46.1% vs 24.7%, respectively; p < 0.001). The prevalence of VTE was higher in the chemoprophylaxis group (3.62% vs 2.03%, respectively; p < 0.001). The median time to VTE occurrence was shorter in the nonchemoprophylaxis group (3.6 vs 6.8 days, respectively; p = 0.0003, log-rank test; hazard ratio 0.685 [0.505–0.926]), and the peak prevalence of VTE occurred in the first 3 postoperative days in the nonchemoprophylaxis group. The average time of initiation of chemoprophylaxis was 1.46 days after surgery. The rates of epidural hematoma were 0.20% (n = 4) in the chemoprophylaxis group and 0.18% (n = 9) in the nonchemoprophylaxis group (p = 0.622).

CONCLUSIONS

The risks of spinal epidural hematoma among patients who receive chemoprophylaxis and those who do not are low and equivalent. Administering anticoagulation therapy from 1 day before to 3 days after surgery is safe for patients at high risk for VTE.

ABBREVIATIONS BMI = body mass index; DVT = deep venous thrombosis; EBL = estimated blood loss; HR = hazard ratio; ICU = intensive care unit; IVC = inferior vena cava; PE = pulmonary embolism; RBC = red blood cell; VTE = venous thromboembolism.

OBJECTIVE

Venous thromboembolism (VTE) after spinal surgery is a major cause of morbidity, but chemoprophylactic anticoagulation can prevent it. However, there is variability in the timing and use of chemoprophylactic anticoagulation after spine surgery, particularly given surgeons’ concerns for spinal epidural hematomas. The goal of this study was to provide insight into the safety, efficacy, and timing of anticoagulation therapy after spinal surgery.

METHODS

The authors retrospectively examined records from 6869 consecutive spinal surgeries performed in their departments at Northwestern University. Data on patient demographics, surgery, hospital course, timing of chemoprophylaxis, and complications, including deep venous thrombosis (DVT), pulmonary embolism (PE), and spinal epidural hematomas requiring evacuation, were collected. Data from the patients who received chemoprophylaxis (n = 1904) were compared with those of patients who did not (n = 4965). The timing of chemoprophylaxis, the rate of VTEs, and the incidence of spinal epidural hematomas were analyzed.

RESULTS

The chemoprophylaxis group had more risk factors, including greater age (59.70 vs 51.86 years, respectively; p < 0.001), longer surgery (278.59 vs 145.66 minutes, respectively; p < 0.001), higher estimated blood loss (995 vs 448 ml, respectively; p < 0.001), more comorbid diagnoses (2.69 vs 1.89, respectively; p < 0.001), history of VTE (5.8% vs 2.1%, respectively; p < 0.001), and a higher number were undergoing fusion surgery (46.1% vs 24.7%, respectively; p < 0.001). The prevalence of VTE was higher in the chemoprophylaxis group (3.62% vs 2.03%, respectively; p < 0.001). The median time to VTE occurrence was shorter in the nonchemoprophylaxis group (3.6 vs 6.8 days, respectively; p = 0.0003, log-rank test; hazard ratio 0.685 [0.505–0.926]), and the peak prevalence of VTE occurred in the first 3 postoperative days in the nonchemoprophylaxis group. The average time of initiation of chemoprophylaxis was 1.46 days after surgery. The rates of epidural hematoma were 0.20% (n = 4) in the chemoprophylaxis group and 0.18% (n = 9) in the nonchemoprophylaxis group (p = 0.622).

CONCLUSIONS

The risks of spinal epidural hematoma among patients who receive chemoprophylaxis and those who do not are low and equivalent. Administering anticoagulation therapy from 1 day before to 3 days after surgery is safe for patients at high risk for VTE.

ABBREVIATIONS BMI = body mass index; DVT = deep venous thrombosis; EBL = estimated blood loss; HR = hazard ratio; ICU = intensive care unit; IVC = inferior vena cava; PE = pulmonary embolism; RBC = red blood cell; VTE = venous thromboembolism.

Venous thromboembolisms (VTEs), including deep venous thrombosis (DVT) and pulmonary embolism (PE), are serious complications that cause considerable morbidity and death.13 An estimated 2 million people develop DVT in the United States annually,22 and approximately 600,000 cases of PE are reported; one-third of PEs lead to death.3 After undergoing spine surgery, up to 31% of patients develop DVT, and up to 7.6% develop PE.17

Although it is known that anticoagulant therapy reduces the number of diagnosed DVTs and PEs in spine surgery patients,10,13,29 many spine surgeons believe that the risk of epidural hematoma is increased when anticoagulation therapy is used. The incidence of epidural hematoma has not been well studied, and whether it is associated with anticoagulation has not been robustly demonstrated.17 Nevertheless, because epidural hematomas are associated with neurological deficits, many spine surgeons minimize their use of anticoagulants to avoid this complication.15,16,32

To prevent complications from chemoprophylactic anticoagulation, most surgical subspecialties have established guidelines for using it.13,20 However, spine surgery lacks robust evidence on the safety, efficacy, and timing of anticoagulation and on the epidemiology of VTE and bleeding complications.15 Instead, most published guidelines conclude that more data are needed so that existing guidelines can be improved.5,15–17 Moreover, existing guidelines, such as those provided by the National Institute for Health and Care Excellence (NICE), do not specify the timing of VTE chemoprophylaxis but instead advise spine surgeons to exercise clinical judgment when using it.20 In the absence of clear guidelines, there is significant variability in the use and timing of VTE prophylaxis after spine surgery.17

The goal of this study was to provide further insight into the safety, efficacy, and timing of anticoagulation therapy after spinal surgery. First, we examined the incidence of VTEs among patients who underwent spine surgery and compared data from patients who received chemoprophylaxis to those who did not. Second, we compared the rates of epidural hematoma that required surgical evacuation between the groups (chemoprophylaxis vs nonchemoprophylaxis groups). Third, we examined the timing of VTE formation and the initiation of chemoprophylaxis in these patients.

Methods

Data Source

All patients who underwent spine surgery in the Departments of Neurological Surgery or Orthopedic Surgery of Northwestern University between January 1, 2009, and May 31, 2015, were identified using the Northwestern University Electronic Data Warehouse (EDW). The EDW is a clinical data repository jointly funded by Northwestern Memorial Hospital, the Northwestern Medical Faculty Foundation, and the Northwestern University Feinberg School of Medicine. Spine surgeries were detected using Current Procedural Terminology codes, and all identified primary spine surgeries were included in the analysis. If patients had multiple procedures that required different admissions during this time frame, each operation was analyzed separately. We excluded any patient who underwent reoperation within 30 days, minor spine surgery (including electrode placement or hardware removal), or a secondary procedure (e.g., surgery for wound dehiscence and hematoma evacuation). For each spine surgery included in the study, data about the patient, the procedure, and the postoperative management and recovery were collected. The study was approved by Northwestern University’s institutional review board.

Patient Data

We collected the following patient data: age at surgery, sex, body mass index (BMI), smoking status (never, current, or quit < 1 year ago), race (Caucasian, African American, Hispanic, Pacific Islander, or other), history of VTEs, history of bleeding disorders, and number of comorbidities (hypertension, cardiac, renal, pulmonary, and endocrine disease) present, as identified by the of International Classification of Diseases, Ninth Revision (ICD-9) codes.

Procedure Data

We collected the following data about the procedures performed: whether an inferior vena cava (IVC) filter was placed prophylactically, the site of surgery (cervical, thoracic, lumbar, or other), whether a fusion was part of the procedure, whether decompression (laminectomy or laminotomy) was a part of the procedure, whether the surgery was staged across multiple days, the length of surgery (minutes), the length of anesthesia (minutes), estimated blood loss (EBL) (milliliters), transfusion of red blood cells (RBCs) (milliliters), whether the patient was admitted to an intensive care unit (ICU), and the length of hospitalization (days).

Outcome Data

We also collected data on the use of chemoprophylactic anticoagulation in our patients. Given recent data showing that spine surgeons who use chemoprophylactic anticoagulation do so in the first few days after surgery,15 we defined chemoprophylaxis as anticoagulation therapy given between 1 day before and 3 days after surgery. Patients who received anticoagulation outside of this window were assumed to have received it therapeutically. We considered any patient who received 5000 U of heparin, 40 mg of enoxaparin, 2500 or 5000 U of dalteparin, or 2.5 mg of fondaparinux between 1 day before and 3 days after surgery to have received it prophylactically (Table 1). We did not include any patient who received a higher dose of any of these anticoagulants or any patient who received aspirin or warfarin in the chemoprophylaxis group.

TABLE 1.

Types of anticoagulant therapy used for chemoprophylaxis

AnticoagulantDose% of Patients (no.)
Heparin5000 U42.28 (805)
Enoxaparin40 mg22.64 (431)
Dalteparin2500 U0.11 (2)
5000 U34.82 (663)
Fondaparinux2.5 mg0.16 (3)

Information about complications within 30 days after the surgery included the cumulative 30-day incidence and timing of VTE (defined as either DVT or PE), cumulative 30-day incidence and timing of epidural hematoma, cumulative 30-day incidence of post–epidural hematoma neurological deficit, all-cause readmission, reoperation, and incidence of death.

Statistical Analysis

Excel 2011 (Microsoft) and Prism 6.0b (GraphPad Software, Inc.) were used to conduct all statistical analyses. Parametric data were recorded as mean ± SD and compared using the Student t-test, and nonparametric data were compared using the Mann-Whitney U-test or chi-square test, as appropriate. Time-to-event data were analyzed using Mantel-Cox statistics. A p value of < 0.05 was considered statistically significant.

Results

Baseline Patient Characteristics

A total of 6869 procedures met the study inclusion criteria. Compared with the nonchemoprophylaxis group (n = 4965), patients in the chemoprophylaxis group (n = 1904) were older (59.70 vs 51.86 years, respectively; p < 0.001), had more comorbid diagnoses (2.69 vs 1.89, respectively; p < 0.001), and were more likely to be female (53% vs 44%, respectively; p < 0.001), to have a history of VTE (5.8% vs 2.1%, respectively; p < 0.001), to have had a history of bleeding disorders in the year before surgery (3.6% vs 2.2%, respectively; p < 0.001), and to have neurological deficits (6% vs 4%, respectively; p < 0.001) (Table 2).

TABLE 2.

Preoperative characteristics of patients

CharacteristicNonchemoprophylaxis GroupChemoprophylaxis Groupp Value
No. of patients49651904
Age in yrs
 Mean ± SD51.86 ± 15.4559.70 ± 14.41<0.001
 Median (95% CI)52 (51.43–52.29)62 (59.05–60.35)<0.001
Sex (% [no.])<0.001
 Male56 (2774)47 (902)
 Female44 (2191)53 (1002)
BMI in kg/m2
 Mean ± SD28.11 ± 5.9629.31 ± 6.83<0.001
 Median (95% CI)27.21 (27.95–28.28)27.98 (29.00–29.62)<0.001
Smoking (% [no.])*<0.001
 Never84 (4159)85 (1621)
 Current15 (734)12 (221)
 Quit <1 yr ago1 (67)3 (57)
VTE history (% [no.])2.1 (104)5.8 (111)<0.001
Epidural hematoma history (% [no.])0.07 (1)0.13 (1)0.4
Bleeding disorder history (% [no.])2.2 (31)3.6 (28)<0.001
Neurological deficit (% [no.])4 (60)6 (44)0.004
No. of comorbidities
 Mean ± SD1.89 ± 1.482.69 ± 1.35<0.001
 Median (95% CI)2 (1.85–1.93)3 (2.63–2.75)<0.001

The numbers and percentages reflect only the data for patients for whom smoking status was known.

Patients in the chemoprophylaxis group had a longer surgery (278.59 vs 145.66 minutes, respectively; p < 0.001), more anesthesia time (363.05 vs 205.05 minutes, respectively; p < 0.001), and a greater EBL (995 vs 448 ml, respectively; p < 0.001) and were more likely to have undergone thoracic surgery (11.2% vs 3.71%, respectively; p < 0.001), staged surgery (62.50% vs 44.30%, respectively; p = 0.013), and fusion surgery (46.1% vs 24.7%, respectively; p < 0.001) (Table 3). Patients in the chemoprophylaxis group also were more likely to have been admitted to the ICU (39.4% vs 10.4%, respectively; p < 0.001).

TABLE 3.

Procedure characteristics

CharacteristicNonchemoprophylaxis GroupChemoprophylaxis Groupp Value
Timing of anticoagulant in daysNA1.46
IVC filter placed (% [no.])1.93 (96)8.56 (163)<0.001
Site of surgery (% [no.])<0.001
 Cervical26.5 (1313)24.2 (461)
 Thoracic3.7 (184)11.2 (213)
 Lumbar69.3 (3442)62.8 (1196)
 Other0.5 (26)1.79 (34)
Fusion (% [no.])24.7 (1225)46.1 (878)<0.001
Decompression (% [no.])33.5 (1664)37.3 (710)<0.001
Staged surgery (% [no.])44.30 (85)62.50 (100)0.013
Surgery time in mins
 Mean ± SD145.66 ± 127.12278.59 ± 181.81<0.001
 Median (95% CI)108 (142.02–149.10)228 (270.42–286.76)<0.001
Anesthesia time in mins
 Mean ± SD205.05 ± 145.26363.05 ± 201.89<0.001
 Median (95% CI)164 (200.90–208.98)309 (353.98–372.13)<0.001
EBL in ml
 Mean ± SD447.98 ± 1383.62994.77 ± 1549.99<0.001
 Median (95% CI)75 (381.45–514.51)400 (902.48–1087.06)<0.001
Packed RBCs transfused in ml
 Mean ± SD1476.04 ± 1805.341315.38 ± 1262.270.004
 Median (95% CI)800 (1256.84–1695.24)900 (1199.35–1431.42)0.721
ICU admission (% [no.])10.4 (518)39.4 (751)<0.001
Length of stay in days (median)15<0.001
HR (95% CI)1.958 (2.589–2.849)0.5107 (0.3510–0.3862)
NA = not applicable.

Rates of VTE

The rates of VTE were 3.62% (n = 69) in the chemoprophylaxis group and 2.03% (n = 101) in the nonchemoprophylaxis group (p < 0.001) (Table 4). The rates of DVT were 3.15% (n = 60) in the chemoprophylaxis group and 1.65% (n = 82) in the nonchemoprophylaxis group (p < 0.001). The rates of PE were 0.79% (n = 15) in the chemoprophylaxis group and 0.60% (n = 30) in the nonchemoprophylaxis group (p = 0.091).

TABLE 4.

Postoperative outcomes within 30 days

OutcomeNonchemoprophylaxis GroupChemoprophylaxis Groupp Value
VTE (% [no.])2.03 (101)3.62 (69)<0.001
 Onset in days
  Mean ± SD5.83 ± 6.418.52 ± 6.770.672
  Median (95% CI)3.37 (4.56–7.09)6.79 (6.89–10.14)0.001
PE (% [no.])0.60 (30)0.79 (15)0.091
 Onset in days
  Mean ± SD5.20 ± 6.3010.87 ± 7.850.243
  Median (95% CI)2.86 (2.89–7.51)7.65 (6.52–15.22)0.001
 PE w/ IVC filter (% [no.])8.33 (8)2.45 (4)<0.001
 PE w/o IVC filter (% [no.])0.45 (22)0.63 (11)0.068
DVT (% [no.])1.65 (82)3.15 (60)<0.001
 Onset in days
  Mean ± SD6.24 ± 6.258.14 ± 6.410.84
  Median (95% CI)3.97 (4.87–7.61)6.82 (6.49–9.80)0.041
 DVT w/ IVC filter (% [no.])29.2 (28)14.1 (23)<0.001
 DVT w/o IVC filter (% [no.])1.11 (54)2.13 (37)<0.001
Epidural hematoma (% [no.])0.18 (9)0.21 (4)0.622
 Onset in days
  Mean ± SD6.17 ± 8.5910.84 ± 9.440.736
  Median (95% CI)3.19 (0.02–12.31)8.98 (−0.88 to 22.56)0.119
 Neurological deficit (% [no.])78 (7)25 (1)0.217
Nonepidural hematoma (% [no.])0.18 (9)0.26 (5)0.504
 Onset in days
  Mean ± SD2.52 ± 3.685.97 ± 4.80<0.001
  Median (95% CI)6.98 (2.41–2.62)11.88 (5.76–6.19)0.536
 Neurological deficit (% [no.])22 (2)60 (3)0.158
Readmission (% [no.])3.83 (190)8.19 (156)<0.001
Reoperation (% [no.])2.22 (110)3.41 (65)<0.001

An IVC filter was placed in 8.56% (n = 163) of the patients in the chemoprophylaxis group and 1.93% (n = 96) of those in the nonchemoprophylaxis group (p < 0.001) (Table 3). To identify any significant differences in the patients who underwent prophylactic IVC filter placement, we performed a subgroup analysis on their preoperative characteristics (Table 5), procedure characteristics (Table 6), and postoperative outcomes (Table 7). The majority of PEs occurred in patients who underwent placement of an IVC filter (4.63% [12 of 259]), and the rate was 0.50% (33 of 6610) for those with no IVC filter, independent of chemoprophylaxis status. Of the patients with an IVC filter, the rates of PE were 2.45% (4 of 163) in the chemoprophylaxis group and 8.33% (8 of 96) in the nonchemoprophylaxis group (p < 0.001) (Table 7). In the patients without an IVC filter, the rates of PE were 0.63% (11 of 1741) in the chemoprophylaxis group and 0.45% (22 of 4869) in the nonchemoprophylaxis group (p = 0.068).

TABLE 5.

Preoperative characteristics of patients who underwent IVC filter placement

CharacteristicNonchemoprophylaxis GroupChemoprophylaxis GroupStrength of Association (95% CI)p Value
No. of patients96163
Age in yrs−3.378 (−6.563 to −0.193)0.0377
 Mean ± SD59.78 ± 15.7863.16 ± 10.23
 Median (95% CI)63 (56.58–62.98)64 (61.58–64.74)
Sex (% [no.])0.789 (0.473–1.318)0.3650
 Male44 (42)38 (62)
 Female56 (54)62 (101)
BMI in kg/m20.451 (−1.496 to 2.397)0.6487
 Mean ± SD29.89 ± 7.1329.44 ± 7.85
 Median (95% CI)28.60 (28.42–31.36)27.92 (28.22–30.65)
Ever a smoker? (% [no.])14.58 (14)19.63 (32)1.431 (0.720–2.842)0.3045
Smoking (% [no.])0.5986
 Never85.3 (81)80.3 (130)
 Current10.5% (10)14.2 (23)
 Quit <1 yr ago4.2 (4)5.5 (9)
VTE history (% [no.])34.4 (33)25.2 (41)0.642 (0.370–1.112)0.1126
Epidural hematoma history (% [no.])0 (0)0 (0)
Bleeding disorder history (% [no.])5.17 (3)5.62 (5)1.091 (0.251–4.753)0.9073
Neurological deficit (% [no.])6.90 (4)4.49 (4)0.635 (0.152–2.648)0.5303
Comorbidities (% [no.])0.8150
 00 (0)0 (0)
 15.21 (5)3.07 (5)
 215.63 (15)14.72 (24)
 335.42 (34)33.74 (55)
 431.25 (30)37.42 (61)
 512.50 (12)11.04 (18)
 Median330 (0.0–0.0)0.5268
TABLE 6.

Procedure characteristics of patients who underwent IVC filter placement

CharacteristicNonchemoprophylaxis GroupChemoprophylaxis GroupStrength of Association (95% CI)p Value
Timing of anticoagulant in daysNA1.57
IVC filter placed (% [no.])100 (96)100 (163)
Site of surgery (% [no.])0.2436
 Cervical13.5 (13)11.7 (19)
 Thoracic31.3 (30)22.7 (37)
 Lumbar55.2 (53)65.0 (106)
 Other0.0 (0)0.6 (1)
Fusion (% [no.])15.6 (15)10.4 (17)
Decompression (% [no.])36.5 (35)20.3 (33)0.442 (0.252–0.778)0.0042
Staged surgery (% [no.])30.2 (29)35.0 (57)1.431 (0.720–2.842)0.3045
Surgery time in mins
 Mean ± SD473.05 ± 311.80547.98 ± 279.77
 Median (95% CI)381 (409.87–536.23)545 (504.71–591.25)0.848 (0.649–1.088)0.1931
Anesthesia time in mins
 Mean ± SD575.74 ± 324.01657.43 ± 308.93
 Median (95% CI)492 (510.09–641.39)623 (609.65–705.22)0.819 (0.626–1.053)0.1178
EBL in ml
 Mean ± SD2326.34 ± 3748.192535.11 ± 2417.16−208.8 (−1123 to 705.1)0.6527
 Median (95% CI)1000 (1322.57–3330.11)1900 (2110.64–2959.58)
Packed RBCs transfused in ml
 Mean ± SD2486.06 ± 2878.982123.97 ± 1509.30362.1 (−335.7 to 1060)0.3069
 Median (95% CI)1500 (1640.76–3331.36)1850 (1836.06–2411.87)
Transfusion (% [no.])48.96 (47)66.26 (108)2.047 (1.223–3.428)0.0061
ICU admission (% [no.])84.4 (81)89.6 (146)1.590 (0.755–3.352)0.2197
Length of stay in days (median)11111.016 (0.792–1.310)0.8943
TABLE 7.

Postoperative outcomes within 30 days for patients who underwent IVC filter placement

OutcomeNonchemoprophylaxis Group (% [no.])Chemoprophylaxis Group (% [no.])OR (95% CI)p Value
VTE31.3 (30)14.7 (24)0.3989 (0.216–0.738)0.0029
PE8.33 (8)2.45 (4)0.277 (0.081–0.945)0.0297
DVT29.2 (28)14.11 (23)0.399 (0.214–0.744)0.0033
Epidural hematoma0 (0)0.61 (1)1.782 (0.072–4.20)0.4419
 Neurological deficitNA100 (1)
Nonepidural hematoma2.08 (2)1.23 (2)0.584 (0.081–4.216)0.5893
 Neurological deficit50 (1)50 (1)
Readmission11.5 (11)12.3 (20)1.081 (0.494–2.366)0.8459
Reoperation13.5 (13)4.29 (7)0.287 (0.110–0.746)0.0071

At least a single-level fusion was involved in 30.60% (n = 2103) of the procedures in our study. Of the procedures in the chemoprophylaxis group, 46.1% (n = 878) involved fusion, whereas 24.7% (n = 1224) of the procedures in the nonchemoprophylaxis group involved fusion (Table 3). To identify any significant differences in the patients who underwent fusion, we performed a subgroup analysis on their preoperative characteristics (Table 8), procedure characteristics (Table 9), and postoperative outcomes (Table 10). In this subgroup, we found no significant differences in the rates of VTE events (3.76% vs 2.61%, respectively), PEs (1.14% vs 0.90%, respectively), or DVTs (2.96% vs 2.21%, respectively) between the chemoprophylaxis and nonchemoprophylaxis groups (p > 0.05%) (Table 10).

TABLE 8.

Preoperative characteristics of patients undergoing fusion

CharacteristicNonchemoprophylaxis GroupChemoprophylaxis GroupStrength of Association (95% CI)p Value
No. of patients1224878
Age in yrs−4.484 (−5.701 to −3.267)<0.0001
 Mean ± SD53.82 ± 13.7958.30 ± 14.37
 Median (95% CI)54 (53.04–54.59)60 (57.35–59.25)
Sex (% [no.])0.1068
 Male50.5 (618)46.9 (412)
 Female49.5 (606)53.1 (466)
BMI in kg/m2−1.016 (−1.571 to −0.461)0.0003
 Mean ± SD28.05 ± 6.1429.06 ± 6.68
 Median (95% CI)27.27 (27.70–28.39)27.75 (28.62–29.51)
Ever a smoker? (% [no.])0.862 (0.680–1.093)0.2190
 Yes17.2 (210)15.2 (134)
 No82.8 (1013)84.8 (743)
Smoking (% [no.])*0.1325
 Never82.8 (1013)84.8 (743)
 Current15.8 (193)13.1 (115)
 Quit <1 yr ago1.4 (17)2.1 (19)
VTE history (% [no.])2.45 (30)5.40 (21)2.200 (1.377–3.516)0.0007
Epidural hematoma history (% [no.])0 (0)0 (0)
Bleeding disorder history (% [no.])1.82 (8)4.88 (19)2.773 (1.200–5.409)0.0131
Neurological deficit (% [no.])3.64 (16)5.40 (21)1.512 (0.777–2.942)0.2201
Comorbidities (% [no.])<0.0001
 017.40 (213)6.95 (61)
 117.16 (210)13.90 (122)
 219.85 (243)19.70 (173)
 323.69 (290)28.47 (250)
 417.40 (213)23.80 (209)
 54.49 (55)7.18 (63)
 Median231 (0.0–1.0)<0.001

The numbers and percentages reflect only the data of patients for whom smoking status was known.

TABLE 9.

Procedure characteristics of patients undergoing fusions

CharacteristicNonchemoprophylaxis GroupChemoprophylaxis GroupStrength of Association (95% CI)p Value
Timing of anticoagulant in daysNA1.47
IVC filter placed (% [no.])1.23 (15)1.94 (17)1.591 (0.790–3.205)0.1894
Site of surgery (% [no.])<0.0001
 Cervical59.8 (732)26.9 (236)
 Thoracic4.3 (52)10.6 (93)
 Lumbar36.0 (440)62.6 (549)
 Other0 (0)0 (0)
Fusion (% [no.])100 (1224)100 (878)
Decompression (% [no.])18.95 (232)26.77 (235)1.563 (1.271–1.922)<0.0001
Staged surgery (% [no.])2.70 (33)2.73 (24)1.014 (0.595–1.729)0.9585
Surgery time in mins0.6387 (0.580–0.688)<0.0001
 Mean ± SD216.55 ± 151.69290.48 ± 143.94
 Median (95% CI)174 (208.05–225.06)257 (280.95–300.02)
Anesthesia time in mins0.625 (0.567–0.673)<0.0001
 Mean ± SD283.52 ± 170.75369.54 ± 159.53
 Median (95% CI)235.50 (273.95–293.10)329.00 (358.97–380.11)
EBL in ml55.59 (−305.3 to 416.5)0.7624
 Mean ± SD1286.58 ± 2803.071230.99 ± 1735.26
 Median (95% CI)250 (944.26–1628.90)600 (1049.60–1412.37)
Packed RBCs transfused in ml531.0 (213.1–848.9)0.0011
 Mean ± SD1601.25 ± 1980.101070.24 ± 1071.44
 Median (95% CI)957 (1246.34–1956.16)750 (932.25–1208.24)
Transfusion (% [no.])19.12 (234)13.90 (122)3.282 (2.583–4.170)<0.0001
ICU admission (% [no.])19.12 (234)40.43 (355)2.872 (2.360–3.494)<0.0001
Length of stay in days (median)250.619 (0.487–0.578)<0.0001
TABLE 10.

Postoperative outcomes within 30 days in patients who underwent fusion

OutcomeNonchemoprophylaxis Group (% [no.])Chemoprophylaxis Group (% [no.])OR (95% CI)p Value
VTE2.61 (32)3.76 (33)1.455 (0.887–2.385)0.1351
 VTE w/ IVC filter26.67 (4)17.65 (3)0.589 (0.108–3.203)0.5380
 VTE w/o IVC filter2.32 (28)3.48 (30)1.523 (0.903–2.568)0.1124
PE0.90 (11)1.14 (10)1.270 (0.537–3.005)0.5849
 PE w/ IVC filter6.67 (1)0 (0)0.276 (0.010–7.312)0.2794
 PE w/o IVC filter0.83 (10)1.16 (10)1.409 (0.584–3.401)0.4434
DVT2.21 (27)2.96 (26)1.353 (0.784–2.335)0.2759
 DVT w/ IVC filter26.67 (4)17.65 (3)0.589 (0.108–3.203)0.5380
 DVT w/o IVC filter1.90 (23)2.67 (23)1.415 (0.789–2.540)0.2421
Epidural hematoma0.08 (1)0.11 (1)1.395 (0.087–22.34)0.8133
 Neurological deficit100 (1)0 (0)
Nonepidural hematoma0.25 (3)0.11 (1)0.464 (0.048–4.471)0.4961
 Neurological deficit33.33 (1)100 (1)
Readmission3.68 (45)7.18 (63)2.200 (1.377–3.516)0.0007
Reoperation2.12 (26)2.39 (21)1.129 (0.631–2.020)0.6823

Of the patients in the chemoprophylaxis group, 5.83% (n = 111) had a history of VTE compared with 2.1% (n = 104) of patients in the nonchemoprophylaxis group (Table 2). To identify any significant differences in the patients with a history of VTE, we performed a subgroup analysis on their preoperative characteristics (Table 11), procedure characteristics (Table 12), and postoperative outcomes (Table 13). We found no significant differences in the rates of VTE events (15.32% vs 25.00%), PEs (3.60% vs 9.62%), or DVTs (13.51% vs 20.19%) between the chemoprophylaxis and nonchemoprophylaxis groups (p > 0.05) (Table 13).

TABLE 11.

Preoperative characteristics of patients with a history of VTE

CharacteristicNonchemoprophylaxis GroupChemoprophylaxis GroupStrength of Association (95% CI)p Value
No. of patients104111
Age in yrs−4.497 (7.945 to −1.049)0.0108
 Mean ± SD58.26 ± 14.2162.76 ± 11.36
 Median (95% CI)58.50 (55.50–61.02)64.00 (60.62–64.89)
Sex (% [no.])1.097 (0.642–1.873)0.7346
 Male49 (51)51 (57)
 Female51 (53)49 (54)
BMI in kg/m2−0.022 (−2.205 to 2.160)0.9838
 Mean ± SD30.58 ± 7.7130.60 ± 8.41
 Median (95% CI)29.05 (29.07–32.08)28.96 (29.01–32.19)
Ever a smoker? (% [no.])13.46 (14)15.32 (17)1.163 (0.541–2.497)0.699
Smoking (% [no.])0.846
 Never86.4 (89)84.6 (93)
 Current12.6 (13)13.6 (15)
 Quit <1 yr ago1.0 (1)1.8 (2)
VTE history (% [no.])100 (104)100 (111)
Epidural hematoma history (% [no.])0 (0)0 (0)2.022 (0.491–8.334)0.321
Bleeding disorder history (% [no.])3.16 (3)6.19 (6)1.098 (0.425–2.837)0.8463
Neurological deficit (% [no.])9.47 (9)10.31 (10)1.098 (0.425–2.837)0.8463
Comorbidities (% [no.])0.8408
 00 (0)0 (0)
 16.73 (7)3.60 (4)
 210.58 (11)13.51 (15)
 329.81 (31)29.73 (33)
 432.69 (34)33.33 (37)
 520.19 (21)19.82 (22)
 Median4.004.000 (0.0–0.0)0.9392
TABLE 12.

Procedure characteristics for patients with a history of VTE

CharacteristicNonchemoprophylaxis GroupChemoprophylaxis GroupStrength of Association (95% CI)p Value
Timing of anticoagulant in daysNA1.45
IVC filter placed (% [no.])31.73 (33)36.94 (41)0.794 (0.451–1.396)0.4220
Site of surgery (% [no.])0.6640
 Cervical22 (23)27 (30)
 Thoracic21 (22)22 (24)
 Lumbar57 (59)51 (57)
Fusion (% [no.])28.85 (30)41.44 (46)1.746 (0.989–3.081)0.0535
Decompression (% [no.])49.04 (51)35.14 (39)0.563 (0.326–0.973)0.0389
Staged surgery (% [no.])9.62 (10)10.81 (12)1.139 (0.470–2.762)0.7726
Surgery time in mins0.935 (0.714–1.220)0.618
 Mean ± SD284.68 ± 252.40301.22 ± 205.33
 Median (95% CI)197 (235.60–333.77)247 (262.59–339.84)
Anesthesia time in mins0.882 (−336.7 to 1007)0.3252
 Mean ± SD363.91 ± 263.61398.35 ± 229.88
 Median (95% CI)285.20 (312.64–415.17)345.00 (355.11–441.59)
EBL in ml335.3 (−336.7 to 1007)0.3252
 Mean ± SD1319.17 ± 2210.35983.90 ± 1524.30
 Median (95% CI)375 (677.35–1960.99)500 (628.26–1339.55)
Packed RBCs transfused in ml821.0 (−142.8 to 1785)0.0936
 Mean ± SD2107.51 ± 2587.801286.55 ± 1000.77
 Median (95% CI)1425.50 (1104.07–3110.96)1007.50 (937.37–1635.74)
ICU admission (% [no.])45.19 (47)58.56 (65)1.714 (0.998–2.941)0.0499
Length of stay in days (median)561.003 (0.767–1.314)0.9793
TABLE 13.

Postoperative outcomes within 30 days of patients with a history of VTE

OutcomeNonchemoprophylaxis Group (% [no.])Chemoprophylaxis Group (% [no.])OR (95% CI)p Value
VTE25.00 (26)15.32 (17)0.543 (0.275–1.072)0.0760
 VTE w/ IVC filter30.30 (10)24.39 (10)0.860 (0.302–2.450)0.7778
 VTE w/o IVC filter22.54 (16)10.00 (7)0.378 (0.126–1.138)0.0752
PE9.62 (10)3.60 (4)0.351 (0.107–1.158)0.0742
 PE w/ IVC filter12.12 (4)4.88 (2)0.372 (0.064–2.171)0.2565
 PE w/o IVC filter8.45 (6)2.86 (2)0.3186 (0.062–1.637)0.1511
DVT20.19 (21)13.51 (15)0.618 (0.299–1.275)0.1899
 DVT w/ IVC filter27.27 (9)24.39 (10)0.742 (0.265–2.077)0.5691
 DVT w/o IVC filter16.90 (12)7.14 (5)0.382 (0.146–0.997)0.0440
Epidural hematoma0 (0)0.90 (1)2.837 (0.114–70.48)0.3319
 Neurological deficitNA100 (1)
Nonepidural hematoma0 (0)0.90 (1)2.837 (0.114–70.48)0.3319
 Neurological deficitNA100 (1)
Readmission9.62 (10)18.02 (20)2.066 (0.917–4.654)0.0756
Reoperation7.69 (8)2.70 (3)0.333 (0.086–1.293)0.0970

Timing of VTE and Chemoprophylaxis

The median time to VTE occurrence was shorter in the nonchemoprophylaxis group (3.37 vs 6.79 days, respectively; p = 0.0001). The peak prevalence of VTE occurred in the first 3 days after spine surgery in patients who did not receive chemoprophylaxis (Fig. 1). The average time of initiation to chemoprophylaxis was 1.46 days after surgery.

Fig. 1.
Fig. 1.

Timing of VTEs in the chemoprophylaxis (n = 1904) and nonchemoprophylaxis (n = 4965) groups. The average times to VTE were 8.52 days in the chemoprophylaxis group and 5.83 days in the nonchemoprophylaxis group (p > 0.05).

Epidural Hematoma Rates

The rates of epidural hematoma were 0.21% (n = 4) in the chemoprophylaxis group and 0.18% (n = 9) in the nonchemoprophylaxis group (p = 0.622). The average onset of epidural hematoma was 10.84 days in the chemoprophylaxis group and 6.17 days in the nonchemoprophylaxis group (p = 0.736) (Fig. 2). Of the patients who developed epidural hematoma, 25% (1 of 4) in the chemoprophylaxis group and 78% (7 of 9) in the nonchemoprophylaxis group experienced neurological deficit (p = 0.217). A history of epidural hematoma was not associated with receiving chemoprophylaxis (0.13% vs 0.07%; p = 0.4) (Table 2).

Fig. 2.
Fig. 2.

Cumulative incidence of epidural hematoma after spine surgery in patients who received chemoprophylaxis and in those who did not. No difference between the groups was found (p = 0.8061, log-rank test; HR 1.159 [95% CI 0.3456–3.922]). POD = probability of detection.

Nonepidural Hematoma Rates

The rates of nonepidural hematoma were 0.26% (n = 5) in the chemoprophylaxis group and 0.18% (n = 9) in the nonchemoprophylaxis group (p = 0.504). The average onset of nonepidural hematoma was 5.97 days in the chemoprophylaxis group and 2.52 days in the nonchemoprophylaxis group (p < 0.001). Of the patients who developed nonepidural hematoma, 22% (2 of 9) in the chemoprophylaxis group and 60% (3 of 5) in the nonchemoprophylaxis group experienced neurological deficit (p = 0.158).

Discussion

VTEs are common after spine surgery,17 and they cause considerable morbidity and death.5,13,26 Although many surgical subspecialties have robust guidelines on the use of anticoagulation therapy after surgery,11 widely accepted guidelines for spine surgery do not exist.6 In particular, recommendations do not address the timing of chemoprophylaxis after surgery, and there are insufficient data regarding the epidemiology of VTEs and bleeding complications such as epidural hematoma.15,20 In this study, we compared patients who underwent spine surgery at our center and received only mechanical prophylaxis and those who received chemoprophylaxis in addition to mechanical prophylaxis, and we analyzed the 30-day rates for development of VTE, rates of epidural hematoma development, and the timing of VTE development and anticoagulation initiation in each group.

Epidural hematomas were rare in our study, with an overall prevalence of 0.19%. This rate is consistent with those in the existing literature, which shows a 30-day rate of epidural hematoma of less than 1% in this population.14,16,21 In a recent systematic review on epidural hematoma development, Glotzbecker et al.16 reported that clinically relevant epidural hematomas occur at a rate of 0%–1% according to pooled data from the 16 studies that met their inclusion criteria. The rate of this complication among our patients who did not receive chemoprophylaxis (0.18%) was equivalent to that among the patients who did receive chemoprophylaxis (0.20%). Consistent with our findings, the pooled data from Glotzbecker et al.16 revealed no difference between epidural hematoma rates for patients given chemoprophylaxis.

The timing of the discovery of epidural hematomas was not significantly different between groups, although the lack of statistical significance might be attributable to the small number of events observed. Important to note is that among patients who experienced epidural hematoma, neurological deficits were more common in the nonchemoprophylaxis group than in the chemoprophylaxis group (78% vs 25%, respectively).

Our overall rate of VTE was consistent with those in the existing literature, although there was considerable variation among series. Some studies accounted only for clinical presentations of VTE, whereas others also screened for subclinical events, which led to reported VTE rates that varied from 0.3% to 31%.8,17 In a recent systematic review on VTE after spine surgery, Glotzbecker et al.17 calculated an overall VTE rate of 2.1% when they pooled data from 25 separate studies, which is comparable to the 2.5% overall rate of VTE we observed in our series.

Our results differ from those of the existing literature by showing that the 30-day rate of VTE among those who received chemoprophylaxis (3.62%) was higher than the rate among those who did not receive it (2.03%). Most studies have found that anticoagulation therapy reduces the incidence of VTE after spine surgery.10,13,20,29 This discrepancy is likely attributable to selection factors that surgeons use to determine whether to administer chemoprophylaxis.3,5 In our study, patients who received chemoprophylaxis had risk factors known to be associated with a higher incidence of VTE; they were older, had a higher BMI, suffered from more comorbidities, were more likely to have a previous history of VTE, and had a longer operation time.1,4,6,26,27,31

We believe that there would have been a great increase in the number of VTEs had the patients in our chemoprophylaxis group not been given anticoagulation. Moreover, we found no significant difference in the rates of PE in the chemoprophylaxis and nonchemoprophylaxis groups, despite a difference in the rate of DVT, which suggests that anticoagulant therapy might lower the rate of PE in patients who are at a higher risk for it. Because PE is associated with high morbidity and death, decreasing the rate of PE in this group has the potential to save many lives.20

Because the placement of an IVC filter to prevent PE in patients at high risk who undergo spine surgery has become more common, we also compared the incidence of PEs while excluding patients who underwent IVC filter placement to minimize confounding. Again, we found no significant difference in the rates of PE between patients who received chemoprophylaxis and those who did not, which suggests that anticoagulant therapy might lower the rates of PE in patients at high risk independent of IVC filter placement. One randomized controlled trial demonstrated that prophylactic IVC filter placement increases the rate of DVT among patients with spinal cord injury.18 Nevertheless, the rates of PE were significantly lower in patients who both received chemoprophylaxis and underwent IVC filter placement than in those who only underwent IVC filter placement, which suggests that there could be a role for investigating the safety and efficacy of using IVC filters in combination with chemoprophylaxis in patients at higher risk who undergo spine surgery.

We found a peak prevalence of VTE in the first 3 days after spine surgery in patients who did not receive chemoprophylaxis (Fig. 1). Given that anticoagulation reduces the rate of VTE in patients undergoing spine surgery,10,13,20,29 our data suggest that prophylactic anticoagulation therapy is most likely to be effective if given during the first 3 days after surgery. Any anticoagulant therapy initiated at a later time might more likely be therapeutic rather than prophylactic.

The results of our analysis of the timing of VTE development and chemoprophylaxis after elective spine surgery build on the existing literature. Lunzer et al.24 showed that for spine patients, postoperative chemoprophylaxis was noninferior to preoperative chemoprophylaxis, although they did not analyze the timing of VTE development and prophylaxis. Kim et al.23 showed that VTE prophylaxis is safe within the first 48 hours after surgery, but they analyzed only patients who were undergoing fixation of traumatic spine fracture. Our data better characterize the appropriate timing of VTE development and chemoprophylaxis after spine surgery.

Our analysis differs from those in the existing literature in that we included a larger, broader group of spine surgery patients. Previous studies of patients undergoing spine surgery have examined the incidence of postoperative VTE,1,4,25,28,30,33 the effectiveness of chemoprophylaxis for VTE prevention,2,7,19,24 and complications from anticoagulant therapy.9,12 However, these researchers limited their patient populations to specific spinal procedures, such as operative fixation after traumatic spine fracture,23 degenerative spinal surgery,33 decompression, and fusion procedures.28 The narrowed focus of the existing studies limits their external validity and generalizability to other spine patients. Here, we present a broader analysis of patients who were undergoing spine surgery.

Our study has several limitations inherent to its retrospective design. First, we could not determine whether the decision to administer chemoprophylaxis was based on the patients’ risk factors, provider preference, or some other cause(s). Second, the use of clinical databases has long been associated with inaccuracies in coding. We found a large number of patients in this study who were coded for a history of malignancy but had no charted evidence of cancer, which led us to exclude the variable altogether. Because the 2 groups in our study were known to be significantly different with respect to several other VTE risk factors, we do not believe it would have had a further effect on our conclusions. In addition, the use of clinical databases also limited us to the amount and type of information we were able to collect. For example, we were unable to evaluate the use of postoperative drains because of the variability in the location of this information, including daily progress notes that cannot be coded reliably, as evidenced by the inaccurate charting of malignancy histories. Third, detection bias might have increased the number of VTE events detected in the chemoprophylaxis group, because the baseline clinical characteristics that placed them at high risk might have prompted more vigilance from their providers. Indeed, patients in the chemoprophylaxis group were more likely to be admitted to the ICU than patients in the nonchemoprophylaxis group (39.4% vs 10.4%, respectively; p < 0.001). Finally, patients who suffered a complication might have sought assistance at a different institution, which would have caused ascertainment bias and underestimation of the true rates of VTE and epidural hematoma.

Despite these limitations, to our knowledge, our study is the only investigation in the spine surgery literature designed specifically to address the timing of initiation of VTE chemoprophylaxis after primary spine procedures.

Conclusions

VTE complications after spine surgery typically occur during the first 3 postoperative days. Chemoprophylactic anticoagulation can be used without an increase in the risk of epidural hematoma, even when it is initiated within the first 48 hours after surgery.

Disclosures

Dr. Koski has direct stock ownership in NuVasive and has been a consultant for NuVasive, Medtronic, and Spine Wave.

Author Contributions

Conception and design: Dahdaleh, Dhillon, Khanna. Acquisition of data: Dhillon, Khanna, Roberts. Analysis and interpretation of data: Dahdaleh, Dhillon, Khanna, Cloney. Drafting the article: Dhillon, Cloney. Critically revising the article: Dahdaleh, Dhillon, Khanna, Cloney, Cybulski, Koski, Smith. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Dahdaleh. Statistical analysis: Dhillon, Khanna, Cloney. Administrative/technical/material support: Dahdaleh. Study supervision: Dahdaleh, Cybulski, Koski, Smith.

Supplemental Information

Previous Presentations

Portions of this work were presented as a Kuntz Scholar orally at the 33rd Annual Meeting of the Section on Disorders of the Spine and Peripheral Nerves, Congress of Neurological Surgeons, Orlando, Florida, March 17, 2016.

References

  • 1

    Akeda KMatsunaga HImanishi THasegawa MSakakibara TKasai Y: Prevalence and countermeasures for venous thromboembolic diseases associated with spinal surgery: a follow-up study of an institutional protocol in 209 patients. Spine (Phila Pa 1976) 39:7917972014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Al-Dujaili TMMajer CNMadhoun TEKassis SZSaleh AA: Deep venous thrombosis in spine surgery patients: incidence and hematoma formation. Int Surg 97:1501542012

  • 3

    Bell WRSimon TL: Current status of pulmonary thromboembolic disease: pathophysiology, diagnosis, prevention, and treatment. Am Heart J 103:2392621982

  • 4

    Born TREngasser WMKing AHKrych AJDahm DLLevy BA: Low frequency of symptomatic venous thromboembolism after multiligamentous knee reconstruction with thromboprophylaxis. Clin Orthop Relat Res 472:270527112014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Bryson DJUzoigwe CEBraybrooke J: Thromboprophylaxis in spinal surgery: a survey. J Orthop Surg 7:142012

  • 6

    Clagett GPAnderson FA JrGeerts WHeit JAKnudson MLieberman JR: Prevention of venous thromboembolism. Chest 114 (5 Suppl):531S560S1998

    • Search Google Scholar
    • Export Citation
  • 7

    Cox JBWeaver KJNeal DWJacob RPHoh DJ: Decreased incidence of venous thromboembolism after spine surgery with early multimodal prophylaxis: clinical article. J Neurosurg Spine 21:6776842014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Cunningham JESwamy GThomas KC: Does preoperative DVT chemoprophylaxis in spinal surgery affect the incidence of thromboembolic complications and spinal epidural hematomas? J Spinal Disord Tech 24:E31E342011

    • Search Google Scholar
    • Export Citation
  • 9

    Du WZhao CWang JLiu JShen BZheng Y: Comparison of rivaroxaban and parnaparin for preventing venous thromboembolism after lumbar spine surgery. J Orthop Surg 10:782015

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10

    Epstein NE: A review of the risks and benefits of differing prophylaxis regimens for the treatment of deep venous thrombosis and pulmonary embolism in neurosurgery. Surg Neurol 64:2953022005

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Falck-Ytter YFrancis CWJohanson NACurley CDahl OESchulman S: Prevention of VTE in orthopedic surgery patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 141 (2 Suppl):e278Se325S2012

    • Search Google Scholar
    • Export Citation
  • 12

    Fang MCMaselli JLurie JDLindenauer PKPekow PSAuerbach AD: Use and outcomes of venous thromboembolism prophylaxis after spinal fusion surgery. J Thromb Haemost 9:131813252011

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Geerts WHBergqvist DPineo GFHeit JASamama CMLassen MR: Prevention of venous thromboembolism: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 133 (6 Suppl):381S453S2008

    • Search Google Scholar
    • Export Citation
  • 14

    Gerlach RRaabe ABeck JWoszczyk ASeifert V: Postoperative nadroparin administration for prophylaxis of thromboembolic events is not associated with an increased risk of hemorrhage after spinal surgery. Eur Spine J 13:9132004

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Glotzbecker MPBono CMHarris MBBrick GHeary RFWood KB: Surgeon practices regarding postoperative thromboembolic prophylaxis after high-risk spinal surgery. Spine (Phila Pa 1976) 33:291529212008

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Glotzbecker MPBono CMWood KBHarris MB: Postoperative spinal epidural hematoma: a systematic review. Spine (Phila Pa 1976) 35:E413E4202010

    • Search Google Scholar
    • Export Citation
  • 17

    Glotzbecker MPBono CMWood KBHarris MB: Thromboembolic disease in spinal surgery: a systematic review. Spine (Phila Pa 1976) 34:2913032009

  • 18

    Gorman PHQadri SFRao-Patel A: Prophylactic inferior vena cava (IVC) filter placement may increase the relative risk of deep venous thrombosis after acute spinal cord injury. J Trauma 66:7077122009

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Hamidi SRiazi M: Incidence of venous thromboembolic complications in instrumental spinal surgeries with preoperative chemoprophylaxis. J Korean Neurosurg Soc 57:1141182015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Hill JTreasure T: Reducing the risk of venous thromboembolism (deep vein thrombosis and pulmonary embolism) in patients admitted to hospital: summary of the NICE guideline. Heart 96:8798822010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Jacobs LJWoods BIChen AFLunardini DJHohl JBLee JY: Safety of thromboembolic chemoprophylaxis in spinal trauma patients requiring surgical stabilization. Spine (Phila Pa 1976) 38:E1041E10472013

    • Search Google Scholar
    • Export Citation
  • 22

    Jaffer AK: An overview of venous thromboembolism: impact, risks, and issues in prophylaxis. Cleve Clin J Med 75 (Suppl 3):S3S62008

  • 23

    Kim DYKobayashi LChang DFortlage DCoimbra R: Early pharmacological venous thromboembolism prophylaxis is safe after operative fixation of traumatic spine fractures. Spine (Phila Pa 1976) 40:2993042015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Lunzer AVavken PGrohs JG: A prospective, active-control, non-inferiority study of the effectiveness of low molecular weight heparin in the prophylaxis of postoperative thrombotic events in patients undergoing spinal surgery. Orthop Muscular Syst 4:1852015

    • Search Google Scholar
    • Export Citation
  • 25

    McClendon J JrSmith TRO’Shaughnessy BASugrue PAThompson SEKoski TR: Time to event analysis for the development of venous thromboembolism after spinal fusion ≥ 5 levels. World Neurosurg 84:8268332015

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 26

    Oda TFuji TKato YFujita SKanemitsu N: Deep venous thrombosis after posterior spinal surgery. Spine (Phila Pa 1976) 25:296229672000

  • 27

    Sansone JMdel Rio AMAnderson PA: The prevalence of and specific risk factors for venous thromboembolic disease following elective spine surgery. J Bone Joint Surg Am 92:3043132010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 28

    Schairer WWPedtke ACHu SS: Venous thromboembolism after spine surgery. Spine (Phila Pa 1976) 39:9119182014

  • 29

    Schizas CNeumayer FKosmopoulos V: Incidence and management of pulmonary embolism following spinal surgery occurring while under chemical thromboprophylaxis. Eur Spine J 17:9709742008

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 30

    Schulte LMO’Brien JRBean MCPierce TPYu WDMeals C: Deep vein thrombosis and pulmonary embolism after spine surgery: incidence and patient risk factors. Am J Orthop 42:2672702013

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 31

    Tominaga HSetoguchi TTanabe FKawamura ITsuneyoshi YKawabata N: Risk factors for venous thromboembolism after spine surgery. Medicine (Baltimore) 94:e4662015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 32

    Yi SYoon DHKim KNKim SHShin HC: Postoperative spinal epidural hematoma: risk factor and clinical outcome. Yonsei Med J 47:3263322006

  • 33

    Yoshioka KMurakami HDemura SKato STsuchiya H: Prevalence and risk factors for development of venous thromboembolism after degenerative spinal surgery. Spine (Phila Pa 1976) 40:E301E3062015

    • Search Google Scholar
    • Export Citation

If the inline PDF is not rendering correctly, you can download the PDF file here.

Article Information

Contributor Notes

Correspondence Nader S. Dahdaleh, Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, 676 N Saint Clair St., Ste. 2210, Chicago, IL 60611. email: nader.dahdaleh@northwestern.edu.INCLUDE WHEN CITING Published online September 8, 2017; DOI: 10.3171/2017.3.SPINE161076.Disclosures Dr. Koski has direct stock ownership in NuVasive and has been a consultant for NuVasive, Medtronic, and Spine Wave.

© AANS, except where prohibited by US copyright law.

Headings
Figures
  • View in gallery

    Timing of VTEs in the chemoprophylaxis (n = 1904) and nonchemoprophylaxis (n = 4965) groups. The average times to VTE were 8.52 days in the chemoprophylaxis group and 5.83 days in the nonchemoprophylaxis group (p > 0.05).

  • View in gallery

    Cumulative incidence of epidural hematoma after spine surgery in patients who received chemoprophylaxis and in those who did not. No difference between the groups was found (p = 0.8061, log-rank test; HR 1.159 [95% CI 0.3456–3.922]). POD = probability of detection.

References
  • 1

    Akeda KMatsunaga HImanishi THasegawa MSakakibara TKasai Y: Prevalence and countermeasures for venous thromboembolic diseases associated with spinal surgery: a follow-up study of an institutional protocol in 209 patients. Spine (Phila Pa 1976) 39:7917972014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Al-Dujaili TMMajer CNMadhoun TEKassis SZSaleh AA: Deep venous thrombosis in spine surgery patients: incidence and hematoma formation. Int Surg 97:1501542012

  • 3

    Bell WRSimon TL: Current status of pulmonary thromboembolic disease: pathophysiology, diagnosis, prevention, and treatment. Am Heart J 103:2392621982

  • 4

    Born TREngasser WMKing AHKrych AJDahm DLLevy BA: Low frequency of symptomatic venous thromboembolism after multiligamentous knee reconstruction with thromboprophylaxis. Clin Orthop Relat Res 472:270527112014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Bryson DJUzoigwe CEBraybrooke J: Thromboprophylaxis in spinal surgery: a survey. J Orthop Surg 7:142012

  • 6

    Clagett GPAnderson FA JrGeerts WHeit JAKnudson MLieberman JR: Prevention of venous thromboembolism. Chest 114 (5 Suppl):531S560S1998

    • Search Google Scholar
    • Export Citation
  • 7

    Cox JBWeaver KJNeal DWJacob RPHoh DJ: Decreased incidence of venous thromboembolism after spine surgery with early multimodal prophylaxis: clinical article. J Neurosurg Spine 21:6776842014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Cunningham JESwamy GThomas KC: Does preoperative DVT chemoprophylaxis in spinal surgery affect the incidence of thromboembolic complications and spinal epidural hematomas? J Spinal Disord Tech 24:E31E342011

    • Search Google Scholar
    • Export Citation
  • 9

    Du WZhao CWang JLiu JShen BZheng Y: Comparison of rivaroxaban and parnaparin for preventing venous thromboembolism after lumbar spine surgery. J Orthop Surg 10:782015

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10

    Epstein NE: A review of the risks and benefits of differing prophylaxis regimens for the treatment of deep venous thrombosis and pulmonary embolism in neurosurgery. Surg Neurol 64:2953022005

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Falck-Ytter YFrancis CWJohanson NACurley CDahl OESchulman S: Prevention of VTE in orthopedic surgery patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 141 (2 Suppl):e278Se325S2012

    • Search Google Scholar
    • Export Citation
  • 12

    Fang MCMaselli JLurie JDLindenauer PKPekow PSAuerbach AD: Use and outcomes of venous thromboembolism prophylaxis after spinal fusion surgery. J Thromb Haemost 9:131813252011

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Geerts WHBergqvist DPineo GFHeit JASamama CMLassen MR: Prevention of venous thromboembolism: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 133 (6 Suppl):381S453S2008

    • Search Google Scholar
    • Export Citation
  • 14

    Gerlach RRaabe ABeck JWoszczyk ASeifert V: Postoperative nadroparin administration for prophylaxis of thromboembolic events is not associated with an increased risk of hemorrhage after spinal surgery. Eur Spine J 13:9132004

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Glotzbecker MPBono CMHarris MBBrick GHeary RFWood KB: Surgeon practices regarding postoperative thromboembolic prophylaxis after high-risk spinal surgery. Spine (Phila Pa 1976) 33:291529212008

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Glotzbecker MPBono CMWood KBHarris MB: Postoperative spinal epidural hematoma: a systematic review. Spine (Phila Pa 1976) 35:E413E4202010

    • Search Google Scholar
    • Export Citation
  • 17

    Glotzbecker MPBono CMWood KBHarris MB: Thromboembolic disease in spinal surgery: a systematic review. Spine (Phila Pa 1976) 34:2913032009

  • 18

    Gorman PHQadri SFRao-Patel A: Prophylactic inferior vena cava (IVC) filter placement may increase the relative risk of deep venous thrombosis after acute spinal cord injury. J Trauma 66:7077122009

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Hamidi SRiazi M: Incidence of venous thromboembolic complications in instrumental spinal surgeries with preoperative chemoprophylaxis. J Korean Neurosurg Soc 57:1141182015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Hill JTreasure T: Reducing the risk of venous thromboembolism (deep vein thrombosis and pulmonary embolism) in patients admitted to hospital: summary of the NICE guideline. Heart 96:8798822010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Jacobs LJWoods BIChen AFLunardini DJHohl JBLee JY: Safety of thromboembolic chemoprophylaxis in spinal trauma patients requiring surgical stabilization. Spine (Phila Pa 1976) 38:E1041E10472013

    • Search Google Scholar
    • Export Citation
  • 22

    Jaffer AK: An overview of venous thromboembolism: impact, risks, and issues in prophylaxis. Cleve Clin J Med 75 (Suppl 3):S3S62008

  • 23

    Kim DYKobayashi LChang DFortlage DCoimbra R: Early pharmacological venous thromboembolism prophylaxis is safe after operative fixation of traumatic spine fractures. Spine (Phila Pa 1976) 40:2993042015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Lunzer AVavken PGrohs JG: A prospective, active-control, non-inferiority study of the effectiveness of low molecular weight heparin in the prophylaxis of postoperative thrombotic events in patients undergoing spinal surgery. Orthop Muscular Syst 4:1852015

    • Search Google Scholar
    • Export Citation
  • 25

    McClendon J JrSmith TRO’Shaughnessy BASugrue PAThompson SEKoski TR: Time to event analysis for the development of venous thromboembolism after spinal fusion ≥ 5 levels. World Neurosurg 84:8268332015

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 26

    Oda TFuji TKato YFujita SKanemitsu N: Deep venous thrombosis after posterior spinal surgery. Spine (Phila Pa 1976) 25:296229672000

  • 27

    Sansone JMdel Rio AMAnderson PA: The prevalence of and specific risk factors for venous thromboembolic disease following elective spine surgery. J Bone Joint Surg Am 92:3043132010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 28

    Schairer WWPedtke ACHu SS: Venous thromboembolism after spine surgery. Spine (Phila Pa 1976) 39:9119182014

  • 29

    Schizas CNeumayer FKosmopoulos V: Incidence and management of pulmonary embolism following spinal surgery occurring while under chemical thromboprophylaxis. Eur Spine J 17:9709742008

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 30

    Schulte LMO’Brien JRBean MCPierce TPYu WDMeals C: Deep vein thrombosis and pulmonary embolism after spine surgery: incidence and patient risk factors. Am J Orthop 42:2672702013

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 31

    Tominaga HSetoguchi TTanabe FKawamura ITsuneyoshi YKawabata N: Risk factors for venous thromboembolism after spine surgery. Medicine (Baltimore) 94:e4662015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 32

    Yi SYoon DHKim KNKim SHShin HC: Postoperative spinal epidural hematoma: risk factor and clinical outcome. Yonsei Med J 47:3263322006

  • 33

    Yoshioka KMurakami HDemura SKato STsuchiya H: Prevalence and risk factors for development of venous thromboembolism after degenerative spinal surgery. Spine (Phila Pa 1976) 40:E301E3062015

    • Search Google Scholar
    • Export Citation
TrendMD
Cited By
Metrics

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 794 761 40
PDF Downloads 345 296 25
EPUB Downloads 0 0 0
PubMed
Google Scholar