Subcutaneous Fat Reduction with Injected Ice Slurry

Abstract

Background: Cryolipolysis is a noninvasive method for removal of subcutaneous fat for body contouring. Conventional cryolipolysis with topical cooling requires extracting heat from subcutaneous fat by conduction across the skin, thus limiting the amount and the location of the fat removed. The authors hypothesized that local injection of a physiological ice slurry directly into target adipose tissue would lead to more efficient and effective cryolipolysis. Methods: Injectable slurries containing 20 percent and 40 percent ice content were made using common parenteral agents (normal saline and glycerol), then locally injected into the subcutaneous fat of swine. Ultrasound imaging, photography, histological, and gross tissue responses were monitored before and periodically up to 8 weeks after injection. Results: Fat loss occurred gradually over several weeks following a single ice slurry injection. There was an obvious and significant 55 ± 6 percent reduction in adipose tissue thickness compared with control sites injected with the same volume of melted slurry (p < 0.001, t test). The amount of fat loss correlated with the total volume of ice injected. There was no scarring or damage to surrounding tissue. Conclusion: Physiological ice slurry injection is a promising new strategy for selective and nonsurgical fat removal.

Neural Selective Cryoneurolysis with Ice Slurry Injection in a Rat Model

“…These include: (1) the ability to inject the slurry using a hypodermic needle and syringe; (2) infiltration of the slurry into tissue increases the likelihood of cooling the target nerve; (3) ice slurry is nerve-selective because of its temperature, and although cold enough to cause cryoneurolysis, it is not destructive to other tissue with the exception of adipose tissue. 15 For these reasons, the use of injectable ice…”

“…14 We created a novel method of local tissue cooling, using the phase change properties of ice particles in an ice slurry suspension, and showed that it can safely, selectively, and effectively target lipid-rich tissue in a porcine model. 15 Ice slurries can absorb high quantities of heat, owing to ice's large heat of fusion (334 J/g). In the current study, a biocompatible ice slurry at moderately cold temperatures (around −5°C) and consisting of sterile ice particles suspended in normal saline and glycerol was used to selectively cool a peripheral nerve.…”

“…We had previously shown that such moderately cold temperatures can affect sensory function when delivered topically in humans, 14 and can selectively target lipid-rich tissue in swine when injected as an ice slurry. 15 In this study we aimed to determine whether ice slurry can be used as a novel, injectable, drug-free, and tissue-selective method of cryoneurolysis that can reduce pain. We hypothesized that injection of ice slurry around the rat sciatic nerve will change the nociceptive response from the baseline through neural selective cryoneurolysis.…”

“…Ice slurry composed of normal saline (0.9% sodium chloride) plus 10% glycerol by volume was made as described previously. 15 Briefly, sterile normal saline with 10% glycerol solution was added into a sterile slush maker (Vollrath Frozen Beverage Dispenser; Vollrath Co., LLC, USA) to produce the slush. This was then blended in a sterile blender (HGB150, Waring Commercial, USA) to create an injectable slurry.…”

Acute Renal Failure following Novel Subcutaneous Fat Reduction with Injected Ice Slurry

“…It was first reported in the literature by Garibyan et al in early 2020. 2 A careful review of the literature does not reveal any human trials or FDA-approved use of ice slurry injections for weight-loss. We present the first human case and severe adverse reactions following this new procedure.…”