Panel recommends reclassification of nonthermal shortwave diathermy devices as class II devices

The Orthopaedic and Rehabilitation Devices Panel of the Medical Devices Advisory Committee today recommended nonthermal shortwave diathermy devices be reclassified as class II devices for indications involving postoperative pain and edema.

The panel agreed on the inclusion of the potential risks to the indication of nonthermal shortwave diathermy (SWD), such as cellular or tissue injury, pacemaker and implantable defibrillator interference, tissue necrosis and burns, electric shock, thermal injury from implanted wire leads and metal implants and abnormal cell growth. Additional risks to health related to both on- and off-label use were also discussed in today’s meeting.

“I think the core essence here is to discuss among ourselves the safety and effectiveness. Everything else, we can deliberate on that and make some conclusions, but in those two realms, I think the classification will become self-evident,” John D. Kelly IV, MD, panel chair, said.

John D. Kelly IV

Benefits for patients

When speaking to the benefits of the treatment for patients, the panel agreed some patients may benefit from nonthermal SWD, but the studies presented by the FDA in a systematic review and by industry representatives left panel members with some lingering questions.

“It is the panel’s opinion that there may be a certain subset of patients that benefit from this device; however, we have very serious concerns involving both the veracity and the scientific methodology presented here within,” John D. Kelly IV, MD, panel chair, said.

William L. Rohr, MD, orthopedic surgeon from Mendocino Coast District Hospital, said, “If we’re limited to the data given to us today, I don’t see any conclusive scientific evidence to support these claims. We have been presented with data that suggests it, but I don’t think anybody would consider any of these studies have the rigor to have proven this efficacy.”

The strongest evidence for nonthermal SWD was in postoperative care for breast cancer surgery patients, noted John D. Markman, MD, from the University of Rochester Medical Center in Rochester, N.Y., with a special control for clinical testing expanding beyond that scope. Other panel members noted the measurement of edema, particularly following blepharoplasty, in these studies was less convincing.

Clinical testing

Clinical testing data as a special control recommended by the FDA included: standard study measurements representative of a level 1 study and included randomization, a sham control group, blinding, a well-defined population and treatment, clinically relevant validated treatment measures, adequate power and sample size, appropriate statistical methods, predefined success criteria and a systematic collection of adverse events. Panel members agreed these basic design elements were necessary to support use of nonthermal SWD in treatments for postoperative pain and edema.

Panel members stated their concerns regarding dosage, power, energy imported, pharmacological implications, heat generation and general contraindications for nonthermal SWD. These recommendations were added to the FDA’s list of general controls for treatment, which included biocompatibility, electrical safety, electromagnetic compatibility and interference, clinical testing as well as labeling and nonclinical performance testing to characterize output waveforms and verify specifications.

Although there was agreement among panel members that nonthermal SWD presented no potential unreasonable risk of illness or injury, they noted concerns with applications of the device to the eye.

The panel will meet tomorrow to discuss the reclassification of class III pedicle screw spinal systems to treat spondylolisthesis, with the exception of severe grade 3 and grade 4 spondylolisthesis and degenerative spondylolisthesis.

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