Terminated early due to lack of time.

This study is single center, subject will receive a wireless TENS device. All subjects will be allowed to keep the commercially-available device for use after the study. The primary goal is to test the feasibility of the study design and secondary is to test the preliminary efficacy of the TENS.

This study is single center, subject will receive a wireless TENS device. The coordinator will introduce the study device, be available to answer questions about the device, and assess adverse events. Subjects will be told that we are testing whether TENS, which has shown promise in some patients but needs to be tested formally, has an effects on lower limb swelling . The treatment period will be 3 weeks in duration. After the treatment period, all subjects will be asked to complete the Treatment-period Endpoint-Qualitative interview. All subjects will be allowed to keep the commercially-available device for use after the study.

Inclusion criteria (subjects must…)

1. Have had lower extremity edema for at least 3 months.
2. Currently have edema of at least 2+ (i.e., 3-4mm depression rebounds within a few seconds, but not immediately) on the pitting scale. 21 Pitting will have been assessed by a Clinician, the clinician Co-I within 6 weeks of the screening visit or at the screening visit by the research staff.
3. Willing to not start or change the dosages of any medications that could affect edema for 2 weeks prior to enrollment, and throughout the duration of the study.
4. Not currently using diuretics to control their edema.
5. Not currently using and willing to not start using occupational therapy, physical therapy, or lymphatic massage (at home or by PT) 2 weeks prior to and throughout the duration of the study.
6. Not currently using compression stockings or Velcro or bandage wraps at least 2 weeks prior to enrollment in the study or based on shared decision making of the potential subjects' clinician or the clinician co-investigator are receiving sufficiently little benefit from these therapies to warrant stopping their use for the duration of the study.
7. Have access to a smart phone or device with an Apple or Android operating system with iOS 10 or later, or Android 6 or later. iOS and Android devices must have Bluetooth Low Energy (LE, also called Bluetooth Smart) compatibility. The smart phone or device must have the ability to access the TENS device's Quell App, Zoom App or software and, the ability to connect to the cellular data or Wi-Fi on a daily basis during the trial.
8. Have an active and accessible email.
9. Be willing and able to regularly check the email provided throughout the study.
10. Be able to read English (i.e., is literate, can speak English, and is not blind) because patient-reported outcomes and consent form are only available in English.
11. Be at least 18 years of age.
12. Be able to provide informed consent.

Exclusion criteria (subjects must not…)

1. Be currently using a TENS device for any reason.
2. Have an acute and symptomatic lower extremity DVT (i.e., the diagnosis of DVT is less than 3 months prior to study enrollment).
3. Have started anticoagulants within the past 3 months.
4. Have lower extremity wounds or ulcers.
5. Have a cardiac pace maker or defibrillator.
6. Have epilepsy.
7. Have a leg that is too small or too large for the TENS device to fit securely.
8. Have cellulitis or fibrosis.
9. Have any skin condition at the site where the electrode pads adhere such that the PI/Co-I think the device will not be safe for the subject.
10. Have congestive heart failure.
11. Have chronic kidney disease of stage 3 or greater.
12. Have cirrhosis of the liver.
13. Have previous surgery that removed lymphatic lower leg tissue.
14. Have a diagnosis of lower limb lymphedema.
15. Be pregnant or planning to become pregnant.

from enrollment until end of follow-up, up to 2 months