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 GCS and gradient elastic stockings (GES), 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, compression devices do have side effects, although rare, such as impaired subcutaneous tissue perfusion (Tai et al. 2013).
Three studies have examined the effectiveness of mechanical modalities of prophylaxis on the incidence of DVT and PE in acute SCI individuals. In a case series 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.
Two studies examined the effectiveness of using GES and SCD concurrently. A case series study by Winemiller et al. (1999) retrospectively reviewed individuals for the initial 6-week duration following SCI who used both SCD and GES for 42 days to 6 weeks after injury; a multivariate analysis revealed that the use of SCD and GES was associated with a reduced risk of venous thromboembolism. Chung et al. (2011) conducted a pre-post study examining the effect of combined GES, external sequential pneumatic compression and early ambulation beginning within 1 week of acute SCI on incidence of DVT and PE. Within this population, 43% and 5% of individuals developed DVT and PE, respectively.
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.
Sequential compression and gradient elastic stockings may reduce the incidence of venous thromboembolism during the acute phase post SCI.