External Methods

Although pharmacological measures have been generally the preferred treatment for VTE prophylaxis post SCI, mechanical means of limiting venous stasis can also serve to reduce the incidence of DVT post SCI. Mechanical methods of prophylaxis for venous thrombosis include the use of compression devices. These are generally considered safer forms of prophylaxis than pharmacological methods since there is no risk for bleeding. Compression devices include graduated compression stockings and gradient elastic stockings, as well as IPC/SCD. Compression stockings exert a graded pressure along the lower extremities and are postulated to increase blood flow velocity as well as volume, thereby preventing thrombus formation. IPC and SCD involve an air pump that intermittently and/or sequentially inflates a sleeve fitted around the extremity, and likely involves a mechanism of action that increases femoral vein blood flow. However, it should be noted that use of these devices should be accompanied by twice daily inspection for skin discolouration or breakdown, and broken blood vessels. Pneumatic compression devices are not suitable for individuals with severe arterial insufficiency.

Author Year; Country
Research Design
PEDro Score
Sample Size
Methods Outcome
Becker et al. (1987); USA
RCT
PEDro = 6
N = 15
Population: Age range=17-75yr; Gender: males=11, females=3; Severity of injury: complete/incomplete.
Chronicity: Acute.
Intervention: Rotating treatment tables.
Outcome Measures: Impedance blood plethysmography.
  1. 4/5 control individuals and only 1/10 treated individuals developed positive fibrinogen leg scans.
Matsumoto et al. 2015; Japan
Observational
N = 29
Population: Mean Age: 63.2yr; Gender: males=25, females=4; Injury etiology: High fall (n=11, 38%), Fall at ground level (n=8, 28%), Motor Vehicle Accident (n=4, 14%), Sports (n=3, 10%), Low fall (n=2, 7%), Stairs (n=1, 3%); Severity of Injury: American Spinal Injury Association Impairment Scale (AIS) A=9, AIS B=2, AIS C=8, AIS D=10; Level of Injury: C3-4=11, C5-8=8, T1-12=6, L1-4=4.
Chronicity:<24 hr post SCI.
Intervention: All individuals were monitored for the development of deep venous thrombosis (DVT) after surgery and after they had received Intermittent pneumatic compression (IPC) with a calf pump and elastic stockings. The pump was attached throughout the day for at least 2wk after surgery and the elastic stockings were utilised after a median of 3 days post-surgery. Assessments were conducted 1, 3, 7, 14, and 28 days post-surgery.
Outcome Measures: Development of deep venous thrombosis (DVT), D-Dimer levels.
  1. DVT developed in 12 individuals (41.4%), all of which were located distal to the popliteal vein.
  2. The median length of time from surgery to detection of DVT was 7.5 days.
  3. Seven of the 12 individuals (58.3%) with DVT were classified as AIS A, one classified as AIS B (8.3%), three classified as AIS C (25.0%), and one classified as AIS D (8.3%).
  4. Mean D-Dimer level in individuals who developed DVT was 14.6+13.5ug-ml but this was not significantly different compared to individuals who did not developed DVT (p>0.05) at all assessment time-points except for 7 days after surgery (p=0.028).
  5. Cutoff D-Dimer levels according to the receiver operator characteristic curve did not differ significantly between individuals who developed DVT and those who did not except for 3 days after surgery (p=0.0287).
Chung et al. 2011; Korea
Pre-Post
N = 37
Population: Mean age=53 yr; Gender: Males=26, females=11; Level of injury: cervical-lumbar; Severity of injury: American Spinal Injury Association Impairment Scale (AIS) A-D.
Chronicity: All individuals were studied beginning within 1 week of injury.
Intervention: Only routine mechanical prophylaxis was administered to all individuals in the form of gradient elastic stockings (GES), external sequential pneumatic compression, and early ambulation.
Outcome Measures: Incidence of deep vein thrombosis (DVT) or pulmonary embolism (PE).
Method of Diagnosis: Doppler ultrasonography.
Timing of DVT onset: Routine checks for DVT were performed every 2 weeks beginning usually within 1 week of injury. 27% of individuals developed DVT within 7 days after injury, 8% developed DVT within 2-3 weeks after injury, and 8% developed DVT>1 month after injury.

Incidence of DVT:

  1. 43% of individuals developed DVT.
  2. 2 individuals (5%) developed a PE.
  3. Incidence of DVT in individuals in the present study was higher when compared to studies using pharmacological forms of prophylaxis.
Maxwell et al. 2002; USA
Case Series
N = 111
Population: Mean age=37.5 yr; Gender: males=81%, females=19%; Level of injury: not specified; Severity of injury: paraplegia=41.4%, tetraplegia=58.6%.
Chronicity: Individuals were hospitalized and monitored for an average of 23 ± 20 days following injury.
Intervention: Retrospective review of individuals using sequential compression devices alone or in combination with 5000 IU low dose unfractionated heparin (LDUH) subcutaneously every 12 hr or low molecular unfractionated heparin (LMWH) (Enoxaparin) 30 mg subcutaneously every 12 hr.
Outcome Measures: Incidence of deep vein thrombosis (DVT) or pulmonary embolism (PE).
Method of Diagnosis: Venous duplex ultrasonography.
Timing of DVT onset: Screening for DVT was performed on average 2.3 times during each admission. No other information was provided.

Incidence of DVT:

  1. The overall incidence rate for DVT and PE in SCI individuals was 9.0% and 1.8%, respectively, which was not significantly different.
  2. The incidence of DVT and PE in individuals using compression only was 7.1% and 2.4%, respectively.
Winemiller et al. 1999; USA
Case Series
N = 285
Population: Mean age=26 yr (VTE), mean age=25 yr (no VTE); Gender: males=88% (VTE), males=72% (no VTE); Level of injury: cervical-lumbar/sacral; Severity of injury: Frankel scores: A-B.
Chronicity: All individuals were studied for the initial 6 week duration following injury.
Intervention: Retrospective review of individuals who were administered antithrombotic prophylaxis (sequential compression devices (SCD)/gradient elastic stockings (GES)) or unfractionated heparin (UFH)) for 42 days-6 weeks after injury.
Outcome Measures: Incidence of deep vein thrombosis (DVT) or pulmonary embolism (PE).
Method of Diagnosis: Fibrinogen scans, impedance plethysmography, Doppler studies, venograms, and ventilation-perfusion scanning.
Timing of DVT onset: DVT/PE first detected at a median of 14.5 days after injury. 63% of initial DVT/PE events occurred within the first 3 weeks.

Incidence of DVT:

  1. Overall Incidence of DVT/PE was 19.6%.
  2. Multivariate analysis showed that SCD and GES were associated with a reduced risk of venous thromboembolism.
  3. The risk reduction for heparin compared to SCD/GES was not significant (p=0.06 (95% CI, 0.05-1.08) for the first 14 days, p=0.13 for anytime); SCD/GES and heparin seemed to each be effective.
  4. SCD/GES should be continued after 2 weeks post injury.
Chronic Chronic Chronic

Nash et al. 2000; USA
RCT
PEDro = 8
N = 20

Population: Mean age=27.9yr; Gender: males=20; Level of injury: tetraplegic=20; Chronicity: 2mo-17yr post SCI.
Intervention: Individuals were randomized into one of two groups: 1) Slow sequential pneumatic compression devices (SCD)-15sec compression, 45sec relaxation at 35 mmHg (ankle), 30 mmHg (calf) or 20 mmHh (thigh); or 2) intermittent pulsatile compression (IPC-2sec compression, 18sec relaxation at 160mmHg.
Outcome Measures: Venous flow/min (VFM); average venous velocity (AVV); maximum venous velocity (MVV); for bilateral popliteal and femoral veins at rest (baseline) and during compression.
  1. Popliteal vein: no differences between devices.
  2. Femoral vein: increase in VFM and MVV during IPC versus SCD (p<0.05).
  3. Rest versus compression: VFM, AVV and MVV, all increased during compression (p<0.001).

Of the studies evaluating physical methods for the prevention of DVT, five studies evaluated individuals during the acute phase (<3 months), while one study evaluated individuals during the chronic phase (>3 months) of SCI.

Acute Studies

A variety of mechanical measures to reduce the incidence of DVT post SCI have been studied. Becker et al. (1987) studied whether rotating treatment tables would prevent the development and progression of DVT in individuals with acute SCI. The authors noted that rotating treatment tables had been used up to that time in individuals with acute SCI to maintain spinal cord alignment while facilitating nursing care, allowing even distribution of ventilation and preventing pressure sores. It was hypothesized that because these appliances rotated continuously, they might serve to inhibit thrombosis formation by reducing venous stasis. This randomized trial involved 15 individuals with acute SCIs. Four of the five control (non-rotated) individuals developed distal and proximal thrombi, assessed by I125 fibrinogen scanning and impedance plethysmography while only one of the ten treated (rotated) individuals with SCI developed both distal and proximal venous thrombi (p=0.007).

Matsumoto et al. (2015) examined the use of prophylactic pneumatic compression and elastic stockings without anticoagulation. Individuals were on compression devices all day except when they were out of bed. Elastic stockings were on most of the time except when bathing. DVT was diagnosed in 12 individuals out of the 29 enrolled (Matsumoto et al. 2015). The Consortium for Spinal Cord Injury (2008) clinical practise guidelines, supports the application of mechanical compression devices early after injury since it is the period of highest VTE incidence (p. 38).

Winemiller et al. (1999) examined the medical charts of 285 individuals with SCI and found that sequential pneumatic compression devices (SCD) or gradient elastic stockings were associated with a reduced risk of VTE. Multivariate analysis also suggested a decreased risk of VTE in individuals with SCI treated with heparin in the first 14 days or anytime within 42 days. Although this risk reduction was approximately twice that of SCD/gradient elastic stockings it was not statistically significant. A pre-post study by Chung et al. (2011) also examined the use of gradient elastic stockings, external SCD and early ambulation. To better examine the effectiveness of mechanical compression, individuals were not offered pharmacological prophylaxis which may have contributed to the high DVT incidence (43%) across the study.

Maxwell et al. (2002) retrospectively reviewed individuals with acute SCI for an average of 23 days following injury, who used SCD as thromboprophylaxis. The authors found the incidence of DVT and PE to be 7.1% and 2.4%, respectively.

Chronic Studies

In a small randomized controlled trial, Nash et al. (2000) compared the effects of slow SCD and rapid intermittent pulsatile pneumatic compression devices (IPC) on venous hemodynamics in subjects with complete tetraplegia. Doppler examination of the popliteal and femoral veins in each compression condition revealed significant improvements in hemodynamic parameters in both treatment groups from rest. However, resting volume flow per minute and maximal venous velocity was significantly enhanced in the IPC group. As maximal venous velocity is considered a key measure to evaluate the effectiveness of compression devices used for DVT prevention, the authors suggest that IPC is more effective than SCD. It is important to note that incidence of DVT was not recorded in this study. Therefore, further research regarding the incidence of DVT is necessary to truly determine the superiority of one method over the other.

Conclusion

There is level 1b evidence (from one RCT: Becker et al. 1987) that rotating treatment tables reduce the incidence of venous thromboembolism in individuals with acute SCI.

There is level 4 evidence (from one pre-post and two case series: Chung et al. 2011; Maxwell et al. 2002; Winemiller et al. 1999) that sequential compression or gradient elastic stockings are associated with a reduced the risk of venous thromboembolism in acute SCI individuals.

There is level 1b evidence (from one RCT: Nash et al. 2000) that rapid intermittent pulsatile compression devices are more effective than slow sequential compression devices for stimulating venous blood flow in chronic SCI individuals.