Characterization of Transient Alterations of Cutaneous Sensory Nerve Function by Cryolipolysis
Condition: Adiposity
MeSH terms: Obesity
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): Zeltiq CoolSculpting device
Intervention type(s): Device
Intervention description(s): 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."
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: cryolipolysis, sensory nerve function, Zeltiq