This pre-market, interventional, single-arm study aims to evaluate the safety and efficacy of LinneaSafe 30% polymethylmethacrylate (PMMA) for gluteal augmentation. The study will include 119 patients, with a total recruitment of 137 to account for a 15% drop-out rate. Eligible participants are men and women over 18 years old who express interest and are deemed suitable for the procedure. The primary safety outcome is the incidence of adverse events, while the primary efficacy outcome is patient satisfaction.

This pre-market, interventional, single-arm study aims to evaluate the safety and efficacy of LinneaSafe 30% polymethylmethacrylate (PMMA) for gluteal augmentation. The study will include 119 patients, with a total recruitment of 137 to account for a 15% drop-out rate. Eligible participants are men and women over 18 years old who express interest and are deemed suitable for the procedure. The primary safety outcome is the incidence of adverse events, while the primary efficacy outcome is patient satisfaction.

Patient recruitment will be conducted via social media. After signing the consent form, participants will undergo screening, including laboratory tests, gluteal ultrasound, and bioimpedance. The procedure (T0) involves baseline photos, gluteal measurements, and intramuscular PMMA augmentation (maximum 300 mL), followed by an evaluation of patient and clinician satisfaction. Follow-ups include online assessments at T1 week and T3 months to monitor adverse events. At T6 months, patients will undergo clinical evaluation, laboratory tests, photos, and satisfaction assessments, with the possibility of a retouch (up to 120 mL) if necessary, followed by an additional online check-up after one week. The final evaluation at T12 months will include photos, gluteal measurements, laboratory tests, ultrasound, bioimpedance, and an overall assessment of safety and efficacy.

Inclusion Criteria:

• Men and women;
• Older than 18 years;
• Signed Informed Consent Form;

Exclusion Criteria:

• Prior intramuscular filling with PMMA for volumization of the buttocks or other body areas (reported by the patient or verified on ultrasound).
• Clinical history or evidence on ultrasound of intramuscular injection of liquid/industrial silicone, hydrogels (except hyaluronic acid and absorbable biostimulators performed up to 6 months before), synthol, potenay, ADE vitamins or other products in the glutes
• Pregnant or breastfeeding women
• Presence of silicone prosthesis for gluteal augmentation;
• Levels of 25 hydroxy vitamin D > 60 mg/mL;
• Vitamin D supplementation in the 3 months prior to the procedure - even with 25 hydroxy vitamin D levels between 15 and 60 mg/mL
• Altered PTH (less than 12pg/mL or greater than 65 pg/mL CRP greater than 1 mg/dL (or 10 mg/L)
• Erythrocyte sedimentation value 2 times higher than normal;
• Women with testosterone levels greater than 70 ng/dL
• Women with estrogen levels greater than 450 pg/mL
• Urea value greater than 50 mg/dL
• Creatinine value greater than 1.3 mg/dL
• Glomerular filtration rate less than 90 mL/min
• Rheumatoid factor value greater than 79 UI/mL
• Ionic calcium values greater than 5.2 mg/dL (or 1.30 mmol/L)
• Total calcium value greater than 10.5 mg/dL
• Iron value greater than 175 µg/dL
• Ferritin value greater than 336 ng/dL
• Calcitriol greater than 90.1pg/dL
• Uncontrolled diabetes (fasting blood glucose > 100mg/dL)
• Antinuclear factor (ANA) > 1:160;
• Personal history of more than one episode of pain due to kidney stones (except during pregnancy)
• Ratio of urinary calcium and urinary creatinine in an isolated urine sample > 250.
• Patients using medications for cancer treatment
• Patients with lupus, systemic scleroderma, dermatomyositis, granulomatous diseases
• Any other contraindications mentioned in the product's instructions for use, such as: history of evolving autoimmune disease, during treatment with immunosuppressants, or in any disorder or active skin infection. The use is absolutely contraindicated in cases of active herpes lesions. In cases of herpetic history, prophylactic treatment is recommended. Any inflammatory reaction from injections is also a contraindication.