Characterization of Transient Alterations of Cutaneous Sensory Nerve Function by Cryolipolysis
Cryolipolysis with Zeltiq CoolSculpting device is a novel method of non-invasive fat removal. The technique works by application of cold plates to the skin surface for a single cooling cycle lasting 60 minutes, after which a cold-induced inflammatory panniculitis leads to selective loss of fat. There is no histologic evidence of necrotic or inflammatory damage to skin or nerves, however a single small human study has reported prolonged temporary altered sensation (hypoesthesia) in the area of cryolipolysis procedure. This hypoesthesia seen in about 2/3 of patients, is completely reversible, lasts up to 8 weeks after treatment, and suggests that cooling under these conditions can temporarily alter sensory nerve function.
The purpose of this study is to further characterize the reversible cutaneous sensory function alteration after cryolipolysis with Zeltiq CoolSculpting device. Using multiple modalities of sensory nerve function we hope to elucidate the details of cryolipolysis induced sensory nerve alteration.
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: No masking
Primary Purpose: Basic Science
|Official Title:||Characterization of Transient Alterations of Cutaneous Sensory Nerve Function by Cryolipolysis|
- Vibration Detection Threshold (VDT) [ Time Frame: within 48-72 hours after treatment ]VDT was evaluated using a computerized vibrometer with 1cm2 contact probe placed perpendicularly on the skin (TSA-II, Medoc Inc., Ramat Yishai, Israel). This device gradually increased the vibration magnitude until the subject pressed a "stop" button to indicate when they first felt the vibration. This test was repeated 8 times. The values presented in the data table were averaged over all repeats.
- Mechanical Detection Threshold (MDT) [ Time Frame: 48-72 hours post treatment ]MDT was evaluated using von Frey Filaments. The up-down method, which evaluates the threshold force for appearance and disappearance of a touch sensation reported by the subject, was used until 3 values were obtained. The values presented in the data table were averaged over all repeats.
|Study Start Date:||December 2012|
|Study Completion Date:||August 2013|
|Primary Completion Date:||August 2013 (Final data collection date for primary outcome measure)|
All subjects were randomized to have either the left of right flank treated with single the Zeltiq CoolSculpting Device, which is an FDA approved cooling device used for non-invasive and selective reduction of fat around the flanks. Sensory testing was done before and after the procedure.
Device: Zeltiq CoolSculpting device
This is an FDA approved cooling device used for non-invasive and selective reduction of fat around the flanks, an area commonly referred to as the "love handles."
No Intervention: Control
All subjects were randomized to have either the left of right flank treated with single the Zeltiq CoolSculpting Device. The untreated flank served as the internal control for each subject.
Study design We undertook an open-label, prospective study at the Massachusetts General Hospital (MGH) (Boston, USA) between December 2012 and July 2013. The study was approved by the MGH Institutional Research Board and was registered at ClinicalTrials.gov (NCT01673113). Written, informed consent was obtained from all participants prior to participation in the study. The study conformed to the standards set by the Declaration of Helsinki and Good Clinical Practice Guidelines.
Eleven healthy subjects were enrolled in the study. They were randomized to have either the left or right flank treated with a single cycle of cryolipolysis. Baseline measurement of sensory function was evaluated using QST at the treated and control (untreated) flank for each subject. Histamine iontophoresis was used to evaluate itch duration and intensity on the treated and control flank for each subject. All sensory function testing, including responses to histamine-induced itch, were assessed at 48-72 hours, and Day 7, 14, 21, 35 and 56 post-treatment. In 6 subjects, skin biopsies (3 mm diameter) for histological analysis of nerve fiber density at the treated flank were taken at baseline, 48-72 hours, Day 21 and 56 post-treatment.
Cryolipolysis procedure All subjects received cryolipolysis treatment to the flank above the iliac crest, on one side of the body. The untreated (contralateral) flank served as the control throughout the study. Subjects were randomized to have right or left flank treated and randomization was achieved with a computer-generated randomization code. The treatment site was identified, assessed and marked by a single, unblinded investigator. The sensory testing site within the flanks was marked and registered using a transparent plastic sheet, aligned using cutaneous landmarks including nevi or scars, and photographed with the subject in a standard position, to ensure that the same area was tested on follow-up visits.
Cryolipolysis was performed using an EzApp6.3 applicator (CoolScultping, Zeltiq Aesthetics Inc, Pleasanton USA) and standard settings at cooling intensity factor (CIF) of 41.6, corresponding to heat transfer of -73mW/cm2, applied for one hour.
Quantitative sensory testing (QST) The QST protocol consisted of a series of 7 sensory tests. The QST procedure started with the evaluation of mechanical followed by thermal thresholds.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01673113
|United States, Massachusetts|
|Wellman Center for Photomedicine, MGH|
|Boston, Massachusetts, United States, 02114|
|Principal Investigator:||R. Rox Anderson, MD||Massachusetts General Hospital|