Heat Packs and Heating Pads Make Up 83% of FDA Reports on Physical Therapy Devices

Passive thermal packs and powered heating pads account for 83% of US Food and Drug Administration device reports involving electrophysical agents, the energy-based devices used in rehabilitation and symptom relief, according to a study published on October 28 in Frontiers in Medical Technology.

The retrospective descriptive study, by Doğukan Kurç of the Department of Physiotherapy and Rehabilitation at Istanbul Medipol University in Türkiye, examined public reports in the FDA's Manufacturer and User Facility Device Experience (MAUDE) database received from January 1, 2016, through December 31, 2025. It covered 31 product categories, including electrical and magnetic stimulation, therapeutic ultrasound, optical therapy, shortwave and microwave modalities, iontophoresis and external thermal products.

Concentrated in a few product lines

After screening, the main analysis included 4,934 reports. Passive hot and cold packs made up 2,343 reports (47.5%) and powered heating pads 1,751 (35.5%), the study said. Electrical stimulation and multimode stimulators accounted for 413 reports (8.4%).

Reports were also concentrated within individual product lines. ThermaCare accounted for 1,705 reports (34.6%) under Pfizer, Angelini and Bridges labels, more than the 1,379 reports attributed to the largest single manufacturer group, according to the paper. Manufacturers submitted 77.5% of the reports, distributors 8.7%, voluntary reporters 8.9% and user facilities 4.8%. Reports were classified as injuries in 65.1% of cases and as malfunctions in 33.8%.

MAUDE captures suspected device problems and associated health effects through mandatory and voluntary reporting pathways, and the reports contribute to evidence used to reassess device performance, instructions and risk controls after a product reaches the market, the paper noted.

The largest annual total, 933 reports, was received in 2019, with ThermaCare contributing 539 of them. The author noted that such receipt-year patterns describe when reports entered the FDA dataset and are influenced by reporting delays and practices.

What the reports recorded

Cutaneous injury or reaction codes appeared in 2,786 reports (56.5%), and pain or abnormal sensation in 652 (13.2%). Hospitalization was recorded in 138 reports (2.8%). Excluding the two dominant thermal families left 840 reports, in which cutaneous codes appeared in 44.8% and neurological or neuromuscular codes in 7.9%.

Eleven reports recorded a death as a patient outcome. The study said these described varied circumstances; for example, four reports describing fatal residential fires or related legal and insurance allegations involving heating pads "did not establish four device-caused deaths."

Limits and recommendations

The author wrote that MAUDE "contains selected, incomplete and sometimes contradictory reports, without device-use denominators or independent causal verification." Device and application classifications were made by a single reviewer without independent validation, and coded outcomes were not clinically adjudicated, the paper said.

The study recommends surveillance organized around identifiable product lines, the mode in which a device was actually operating and linked clinical information. It suggests a prospective, modality-specific registry could connect treatment exposure and patient vulnerability to observed outcomes.

The paper, which was peer reviewed, reported no external funding and no conflicts of interest. It is published open access under a Creative Commons Attribution licence.