Does external ultrasonic liposuction work well?

Maybe: Any external technique that can achieve an internal temperature of between 38-42 degrees celcius has the potential to work on melting fat. The term liposuction is incorrect because in these cases the fat is left behind for the body to absorb. Liposuction is a more invasive procedure requiring an incision to insert the suction cannula to extract the fat permanently.

It might: Most non-invasive types of fat removal are not as effective as standard liposuction. Recently, there has been a growth in the number of techniques available, but the technology is still not as advanced.

Debatable: External non-invasive therapies are popular, but efficacy is not usually comparable to more traditional therapy namely liposuction.

Varies with machine: The older, non-focused ultrasound machines did not work particularly well. The new, high-intensity focused ultrasound (hifu) machines, like liposonix, do indeed work, and removal fat. But... The treatment can be painful.

Not really : Anything topical for fat reduction has minimal impact at reducing fat.