Socio-cultural aspects, such as the idealization of skinny and physically perfect bodies, influence female body perception.1,2 Diets, exercises and esthetic procedures are alternatives that may help improve the perception of physical appearance.3–6 Therefore, a few modalities, have been developed for the purpose of sculpting the body and reducing localized fat more safely and non-invasively, such as cryolipolysis.5,7 This technology uses low temperatures8,9 to induce a process of apoptosis and inflammation that will eliminate the adipocytes and consequently reduce the adipose layer of the treated region.3 According to Manstein et al.,10 this technique generates prolonged, localized and controlled cooling which is capable of damaging the fatty tissue without damaging the skin and other adjacent tissues.10 This selective lesion occurs due to the greater susceptibility of the fat cells to cold exposure.11,12

Research on cryolipolysis has been growing and new evidence is available. The latest systematic review showed that reduction of the adipose layer can approach 30% per treated region.3,5 There are a few clinical trials showing that the reduction of the fat layer can reach 17.4%–20.4% after 2 months13,14 and 21.5%–25.5% after 6 months of treatment.7,14 In addition, an epidemiological study showed that two sessions per area were required to obtain some satisfactory result, with the exception of the abdomen that acquired satisfactory results with only 1 session in 21% of the cases.15

Although the literature reports the efficacy and safety of cryolipolysis4,7,14,16–18 this evidence has some methodological issue, such as nonrandomization and no comparator group, which may result in important biases. Also, there is no consensus in the literature regarding the ideal treatment protocol, like parameters of the device, periodicity and number of sessions required per body region.3,5 Another contradictory point concerns the population that presents the best therapeutic response, since the studies do not present a specific range of body mass index.13,19,20

These divergences between studies are a factor of imprecision for clinical decision-making and elaboration of the treatment plan. Thus, the objective of the present study was to evaluate the effects of one single session of cryolipolysis on the subcutaneous adipose layer thickness of the lower abdomen, adverse effects, pain and patient satisfaction of healthy women through a randomized controlled trial with a blinded assessor.

Forty-four women were evaluated for eligibility criteria, but only 38 were included for randomization and 34 completed the study. Fig. 2 shows the detailed flowchart of participant selection, group allocation and follow up losses. The groups were homogeneous at the beginning of the study as can be seen in Table 1.

Fig. 2.

Flowchart of the study.

(0.41MB).

No significant differences were demonstrated between the IG and CG at any evaluation time for fat thickness measured by US (30 days: 0.05cm (95% CI −0.12, 0.22), 60 days: 0.05cm (95% CI −0.11, 0.20) and 90 days: 0.04cm (95% CI −0.7, 0.25)), SF (30 days: −0.09cm (95% CI 0.25, 0.08), 60 days: −0.14cm (95% CI −0.36, 0.09) and 90 days: −0.001cm (95% CI −0.24, 0.23)), AC1 (30 days: 0.42cm (95% CI −1.14, 1.9), 60 days: −0.1cm (95% CI −1.74, 1.54) and 90 days: −0.007cm (−1.9, 1.9)) and AC2 (30 days: 0.18cm (95% CI −0.84, 1.20), 60 days: −0.13cm (95%CI: −1.61, 1.35) and 90 days: −0.31cm (95%CI: −1.61, 1.00)). See Table 2.

The median point on NPRS was 7 (range 3–8) at M1, also 7 (range 5–10) at M4, 3 (range 1–5) at M2 and 2 (range 1–5) at M3. None of the volunteers interrupted the procedure due to pain. The most reported side effects were change in sensitivity, bruises, petechia, edema, pain and itchiness which resolved within the first 30 days after intervention.

The IGAIS, that evaluated the patient's satisfaction, showed that 59% of the participants noticed no change after the protocol, while only 18% and 23% of them reported slight and moderate improvements, respectively. None of the individuals of the IG reported great improvement.

We aimed to evaluate the effects of a cryolipolysis protocol on the thickness of the lower abdomen adipose layer of women. No significant changes were noticed between the groups at any follow up time points. The current study is one of the first studies to report an unfavorable result for this localized fat treatment adding to the scientific literature new observations about the application of cryolipolysis on the lower abdomen of healthy women.

Sasaki et. al. treated 55 abdomens with a cooling intensity factor (CIF) of 42 (−72.9mW/cm2) for 60min followed by massage and found a decrease of 27% (average of 1cm) of the skinfold between baseline and 6 months after a single application.7 With the same treatment protocol, Boey and Wasilenchuk17 evaluated 9 abdomens with ultrasound and reported a mean reduction of 12.6%±7.2% (0.26±0.19cm) on the non-massaged side and 21%±8.5% (0.42±2.2cm) on the massaged side after two months.17 However, is important to be careful when interpreting these findings due to the absence of a control group.

Even though no favorable results were found for the reduction of the fatty layer, our treatment protocol was based on previous studies that demonstrated the efficacy of cryolipolysis.3,27 Moreover, we chose an intervention protocol that resembled the clinical practice, since there is still no consensus in the literature regarding the parameters of the device, periodicity and number of sessions.3,5 The CIF values vary between 33 (−64mW/cm2) and 42 (−72mW/cm2),3 or go up to −15°C.8,9 The minimum application time reported is of 30min while the maximum time is of 120min/cycle.3 An in vivo study with subdermal analysis observed that when performing an external exposure to cold with CIF of 42 for 60min, the adipose tissue can reach temperatures between 7°C and 17°C.7 According to Pinto et al.,28 direct exposure of adipose cells (in vitro) at 8°C for 10 or 25min induces lipid crystallization.28 We applied the cryolipolysis for 50min and used −10°C external exposure temperature, equivalent to a CIF of 42,29 which fits the parameters noted above.

The adverse effects found are in agreement with those already reported in the literature: erythema, pruritus, edema, altered sensitivity and pain.5 The pain was more intense in the first minutes of intervention, but tolerable, considering that no volunteer asked to interrupt the procedure. These findings are similar to the ones reported by Dierickx et al.,30 who reported that 96% of the subjects reported minimal discomfort during the procedure and only 4% reported severe pain, which also occurred within the first few minutes of treatment and also did not cause discontinuation of treatment.30

The observation of any changes in the fat thickness of the IG at any assessment time reflected on the results of the IGAIS. While 59% of the subjects in our intervention group did not notice any change after treatment, the individual in the study by Sasaki et al.7 showed a significant improvement of the fat thickness and reported a moderate change in body remodeling after cryolipolysis.7

Among the limitations of this study we can mention the absence of a food diary referring to the nutritional habits of volunteers and a better control of the level of physical activity, two topics that would have helped us to better characterize and analyze the sample during the follow up. Although it is difficult to blind the volunteers due to the characteristics of the treatment, maybe a placebo application could have been used so that the bias of the absence of treatment could be minimized. The absence of biochemical analyzes can also be considered a limitation of the study, since these could help in the understanding of our findings.

Despite the limitations, this is the first randomized clinical trial with blinded assessor of the outcomes that evaluated the effect of a single application/session cryolipolysis on the thickness of the adipose layer in healthy women compared to a control group. The design is one of the strengths of this study, since randomized controlled trials are the gold standard to analyze the efficacy of an intervention.31 Our study also stands out for including only one gender, one specific range of BMI and for respecting the physiological menstruation period.

Finally, the results of this study should be considered to help clinical decision regarding the use of this therapy in healthy Brazilian women between 18 and 48 years old, with low level of physical activity and BMI between 18.5 and 27kg/m2, since the literature lacks evidence with high methodological rigor. In addition, there are some studies that have already demonstrated the benefits of cryolipolysis after more than one session,32,33 even associated with diet13 or with other therapeutic resources such as shock waves.34 However, besides the study design these studies have different populations,13 parameters and periodicity13,32–34 and outcomes.34 Despite this, the studies mentioned above should be taken into account and new research is encouraged, with methodological rigor, whether cryolipolysis associated with other resources or diet or with more than one session is able to reduce the infra-abdominal fat layer of healthy women.

A single session of the cryolipolysis with the protocol used was not effective for reducing infra-abdominal adipose layer thickness after 30, 60 and 90 days of its application. Also, the majority of the healthy women were not satisfied since the treatment did not show an improvement in fat thickness. Cryolipolysis caused pain and some adverse effects, such as change in sensitivity, bruises, petechia, edema, and itchiness, that were quickly resolved.

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

The authors declare no conflicts of interest.