USA FDA Findings from Approval of Silimed Breast Implants

December 24, 2012: Authored by: Alpha Health Asia Staff

FDA Approval of Mammary Implants Manufactured by Silimed®

On 9 March 2012, the USA FDA approved implants manufactured by Silimed. The PMA is available on the FDA website: http://www.accessdata.fda.gov/cdrh_docs/pdf7/P070004b.pdf (Reference PMA P070004: FDA Summary of Safety and Effectiveness Data) is sponsored by Sientra, Inc; Silimed is the manufacturer of the implants. Like other approved mammary implants in the USA, a condition of the approval requires post-approval studies that will asses long-term outcome and risks.

USA FDA PMA Summary & Key Findings:

Patients, Time Frame & Implants Used:
-Treatment Time Frame: November 11, 2002 through June 23, 2007
-Data collected through: December 20, 2010
-Results reported are through 3 year post operative data
-Investigation Sites: 36
-Surface Types of Implants Used in Study: Smooth, Textured
-Implant Shapes used in Study: Round, Shaped
-Number of Patients Enrolled: 1,788 (76% available for analysis at 3 year post-operative visit)
-Number of Implants Used: 3,506

Usage:
-Primary Augmentation: 1,115 patients
-Primary Revisions-Augmentation: 362 patients
-Reconstruction: 229

Who is Sientra, Inc. and How is Sientra Associated with Silimed?
Sientra is the USA based company that sponsored the PMA; Silimed is the manufacturer of implants for Sientra and of the implants used in the PMA. This information is taken directly from the PMA:

“Silimed Industria de Implantes, Ltda. (hereinafter called “Silimed-Brazil”), the company that manufactures the Implants for Sientra, is located in Rio de Janeiro, Brazil. Silimed- Brazil began manufacturing its silicone-based medical devices in 1981. To date, Silimed- Brazil has distributed nearly half a million high-strength silicone gel breast implants equivalent or corresponding to the PMA-approved Implants in Europe, South America, Australia, Asia, and Africa. These implants have not been withdrawn from any foreign market for any reason.”

“In September 2002, Silimed-U.S. received FDA approval to begin its Core Clinical Study for its Silicone Gel Breast Implants. The Core Clinical Study is the primary clinical set in this PMA. In April 2007, Sientra purchased substantially all the assets of Silimed-U.S. and is now the sponsor of the PMA.”

FDA Notes on Silimed Mammary Implant Construction:
The PMA contains the following notes regarding construction of the implant shell:
“Shell – The extent of cross-linking was measured for smooth and textured implant shells. The percent weight gain and crosslink density were uniform over the three lots tested. The physical properties of cured samples of all elastomer lots used for breast implant shells are measured to ensure that they meet or exceed pre-established material specifications for use in the manufacture of the implant shells. This testing demonstrated that the extent of cross-linking of the elastomers used in the shell is sufficient to ensure that shells meet the ASTM F703 [1] specification of a minimum 2.5 lb break force and >350% elongation.”

Regarding the silicone gel, the PMA states:
“Gel – Using penetrometer testing, every lot of gel is tested to ensure that the crosslink density conforms to predetermined specifications. The uniformity of the crosslink density
across all lots of gel used in the implants is ensured by testing each gel lot used for Implant manufacture. All lots of gel used in the implants have an extent of cross-linking sufficient to achieve the internal specification.”

and:
“Gel cohesivity and penetration testing were conducted to assess the cohesive and cure characteristics of silicone gel, respectively. Gel cohesion testing was conducted on final finished product to standard EN 12180:2000[6], and the samples met the requirements of the test. In-process penetrometer measurements of 425 silicone-gel mixtures performed over a 6-month period revealed that gel cohesion was consistent over time.”

Conclusions from the PMA:
Safety Conclusion:
“The safety assessment of the study implants reveals clinically acceptable rates for complications associated with silicone breast implants, and, in general, demonstrate that the risk of complications associated with Sientra’s breast implants is relatively low.”

Effectiveness Conclusion:
“The effectiveness outcomes demonstrate that the majority of subjects report favorable satisfaction and Quality of Life results. In addition, the majority of patients who underwent a measurement of breast cup size change (augmentation cohort only), report an increase in bra cup-size by at least one cup size.”

Overall Conclusion:
“Overall, the data in this application support the reasonable assurance of safety and effectiveness of this device when used in accordance with the indications for use. The benefits and risks of breast implants are sufficiently well understood for women to make informed decisions about their use. The 3-year clinical results demonstrate that the study implants are reasonably safe and effective for use in primary augmentation, revision-augmentation, primary reconstruction, and revision-reconstruction of the breast.”

PMA Notes on Silimed:
“Silimed Industria de Implantes, Ltda. (hereinafter called “Silimed-Brazil”), the company that manufactures the Implants for Sientra, is located in Rio de Janeiro, Brazil. Silimed- Brazil began manufacturing its silicone-based medical devices in 1981. To date, Silimed- Brazil has distributed nearly half a million high-strength silicone gel breast implants equivalent or corresponding to the PMA-approved Implants in Europe, South America, Australia, Asia, and Africa. These implants have not been withdrawn from any foreign market for any reason.”


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