Buy this Article for $10.95

Have a coupon or promotional code? Enter it here:

When you buy this you'll get access to the ePub version, a downloadable PDF, and the ability to print the full article.


chronic wound healing, negative-pressure wound therapy, retrospective study



  1. Serena, Thomas E. MD, FACS, FACHM, MAPWCA
  2. Buan, John S. PhD


OBJECTIVE: Negative-pressure wound therapy (NPWT) is a mainstay in the treatment of acute and chronic wounds. Following the success of the Vacuum-Assisted Closure system (Kinetic Concepts Inc [KCI], an Acelity Company, San Antonio, Texas), many similar systems were developed with minor variations. However, these systems are best suited to wounds with soft-tissue defects. Moreover, the need for a canister to collect wound exudate adds to the size and weight of the device. A canister-free (CF) NPWT device was cleared by the FDA for the treatment of chronic wounds (Kalypto Medical, Mendota Heights, Minnesota). A retrospective study was designed to evaluate the effectiveness of the CF-NPWT device in promoting wound healing.


METHODS: The authors examined the records of 51 patients treated with the CF-NPWT device over a 21-month period. Study participants were treated in an outpatient setting, had at least 30 days of prior treatment, and carried insurance coverage through Medicare or Medicaid. The comparison of time to heal between groups was conducted using the log-rank, Breslow, and Tarone-Ware tests in conjunction with a Kaplan-Meier analysis.


RESULTS: In the study population, 65% of the wounds achieved complete closure. For unhealed wounds, the mean wound area reduction was 31.9%, and the mean wound depth reduction was 57.5%. The mean time to heal was 56.9 days (95% confidence interval, 46.4-67.4 days).


CONCLUSIONS: The results show that the CF-NPWT system meets or exceeds healing rates previously reported in the literature for canister-based systems. This CF device offers a more portable NPWT option, particularly effective in the treatment of shallow wounds.