Clinical Policy Bulletin: Vacuum Assisted Socket System (VASS)
Aetna considers the Vacuum Assisted Socket System (VASS), a specialized vacuum pump residual limb volume management and moisture evacuation system that is used with an artificial limb to increase suspension and proprioception and improve gait, experimental and investigational because there is insufficient evidence in the medical literature that these specialized components improve the function of the artificial limb or provide any other clinically significant benefits.
Note: An artificial limb that is used with the VASS is covered as a prosthetic when medically necessary for amputees, on the same basis as any other artificial limb.
The Vacuum Assisted Socket System (VASS), developed by Total Environmental Control (TEC), is a specialized device used with artificial limbs to manage residual limb volume fluctuation in amputees. The system consists of a TEC liner, suspension sleeve and air evacuation pump. The device creates an elevated vacuum between the liner and the socket wall. The elevated vacuum promotes natural fluid exchange that regulates volume fluctuation in the residual limb, reduces forces to the residual limb, and increases suspension and proprioception. The manufacturer claims that the enhanced linkage from the vacuum between the liner and the socket wall decreases weight and promotes an improved gait.
According to the manufacturer, studies conducted at St. Cloud (MN) State University indicate a daily volume loss of 6 to 12% in the residual limb (wearing liner, sealing sleeve and expulsion valve). The same sample group (with VASS Technology) lost less than 1 % of residual limb volume. Current published peer-reviewed evidence for the VASS consists of two small un-blinded studies. One study involving 9 amputees compared peak pressures between skin and liner during stance and swing phases during a 20-min walk with a standard prosthetic socket and a vacuum-assisted socket (Bell et al, 2002). Another study examined stump volume in 10 amputees before and after a 30-min walk (Board et al, 2001). Neither of these studies examined the effect of VASS on clinical outcomes (reductions in disability or improvement of function).
In a randomized cross-over study, Klute et al (2011) examined the effect of a VASS system as compared with pin suspension on lower extremity amputees. Unilateral, trans-tibial amputees (n = 20 enrolled, n = 5 completed). Interventions were (i) total surface-bearing socket with a VASS, and (ii) modified patellar tendon-bearing socket with a pin lock suspension system. Main outcome measures included activity level, residual limb volume before and after a 30-min treadmill walk, residual limb pistoning, and Prosthesis Evaluation Questionnaire. Activity levels were significantly lower while wearing the VASS system than the pin suspension (p = 0.0056; 38,000 +/- 9,000 steps per 2 wk versus 73,000 +/- 18,000 steps per 2 wk, respectively). Residual limb pistoning was significantly less while wearing the VASS system than the pin suspension (p = 0.0021; 1 +/- 3 mm versus 6 +/- 4 mm, respectively). Treadmill walking had no effect on residual limb volume. In general, participants ranked their residual limb health higher, were less frustrated, and claimed it was easier to ambulate while wearing a pin suspension compared with the VASS. The authors concluded that the VASS resulted in a better fitting socket as measured by limb movement relative to the prosthetic socket (pistoning), although the clinical relevance of the small but statistically significant difference is difficult to discern. Treadmill walking had no effect, suggesting that a skilled prosthetist can control for daily limb volume fluctuations by using conventional, non-vacuum systems. Participants took approximately 50 % as many steps while wearing the VASS which, when coupled with their subjective responses, suggests a preference for the pin suspension system.
CPT Codes / HCPCS Codes / ICD-9 Codes
Other CPT codes related to the CPB:
97760 - 97762
HCPCS codes not covered for indications listed in the CPB:
Addition to lower limb prosthesis, vacuum pump, residual limb volume management and moisture evacuation system
Addition to lower limb prosthesis, vacuum pump, residual limb volume management and moisture evacuation system, heavy duty
Other ICD-9 codes related to the CPB:
755.20 - 755.29
Reduction deformities of upper limb
755.30 - 755.39
Reduction deformities of lower limb
886.0 - 887.7
Traumatic amputation of other finger(s), arm, and hand (complete) (partial)
895.0 - 897.7
Traumatic amputation of toe(s), foot, or leg (complete) (partial)
997.60 - 997.69
Amputation stump complication
V49.60 - V49.67
Upper limb amputation status
V49.70 - V49.77
Lower limb amputation status
The above policy is based on the following references:
Artificial Limb Specialists. TEC Harmony System [website], Phoenix, AZ: Artificial Limb Specialists; updated February 18, 2002. Available at: http://limbspecialists.com/techarsys.html. Accessed March 29, 2002.
TEC Interface Systems. Products. Waite Park, MN: TEC Interface Systems; 2002. Available at: http://www.tecinterface.com/products_volume.html. Accessed March 29, 2002.
Board WJ, Street GM, Caspers C. A comparison of trans-tibial amputee suction and vacuum socket conditions. Prosthet Orthot Int. 2001;25(3):202-209.
Bell TL, Street GM, Covey SJ. Interface pressures during ambulation using suction and vacuum-assisted prosthetic sockets. J Rehabil Res Develop. 2002;39(6):693-700.
Washington State Department of Labor and Industries, Office of the Medical Director. Otto Bock Harmony Vacuum Assisted Socket System (VASS). Health Technology Assessment Brief. Olympia, WA: Washington State Department of Labor and Industries; updated April 3, 2003. Available at: http://www.lni.wa.gov/ClaimsIns/Files/OMD/OttoBockVASS.pdf. Accessed September 29, 2005.
Klute GK, Berge JS, Biggs W, et al. Vacuum-assisted socket suspension compared with pin suspension for lower extremity amputees: Effect on fit, activity, and limb volume. Arch Phys Med Rehabil. 2011;92(10):1570-1575.
Copyright Aetna Inc. All rights reserved. Clinical Policy Bulletins are developed by Aetna to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. This Clinical Policy Bulletin contains only a partial, general description of plan or program benefits and does not constitute a contract. Aetna does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Aetna or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. This Clinical Policy Bulletin may be updated and therefore is subject to change.