Incidence and natural history of saline-filled breast implant deflations: comparison of blunt-tipped versus cutting and tapered needles.

The silicone shells of breast implants are known to fail. When failure occurs in saline-filled implants, the consequences are always ultimately symptomatic. Failure may be due to shell elastomer fatigue, fold-flaw cracking, faulty valve mechanisms, trauma, and microperforations (defined as perforations that are too small to be seen with the unassisted eye). To determine the incidence and natural history of microperforations, a major manufacturer of saline-filled breast implants was contacted. Over a 30-month period, 289,033 saline implants were sold, and 2844 were subsequently returned due to perioperative deflation. By using a rigorous and reproducible method of evaluating returned deflated saline-filled breast implants, it was found that 197 (0.068 percent of all implants sold) sustained needle damage at the time of insertion and went on to deflate within 6 months. Of the implants returned, overall 6.93 percent were found to have sustained needle trauma as the cause of the deflation, and the incidence appears to be increasing with time. The actual incidence of needle-related deflations may be significantly greater, since these data reflect only those implants which are voluntarily returned to the manufacturer. As a second part of this study, a segment of the silicone shell from a saline-filled breast implant was tested to determine the resistance to puncture using blunt-tipped, tapered, and cutting needles. The blunt-tipped needle required 6.6 times more force to puncture the shell than a cutting needle (p = 0.0011) and 3.2 times more force than a tapered needle (p = 0.0052). The difference in force needed to puncture the shell for a tapered and a cutting needle was not statistically significantly different (p = 0.5045). Microperforations do occur in the operating room and are responsible for a significant percentage of early (less than 6 months) deflations. Blunt needles require significantly more force to puncture the shell of an implant than do cutting and tapered needles, and their use may reduce the incidence of microperforations and subsequent implant deflations.