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BACKGROUND - We present for your consideration, a case of unilateral delayed spontaneous autoinflation of a saline mammary implant. The implant was placed by the senior author in 1990 and remained stable until 2004 when the patient noted an increase in size and firmness. Upon explantation, the implant, initially filled with 275cc of saline, had increased to a volume of 450cc. A meta-analysis of the current literature on spontaneous autoinflation of breast implants will be presented along with a survey of ASPS members conducted in an attempt to quantify the prevalence of this strange phenomenon. Various etiological theories are postulated.
METHODS - A literature review was conducted for articles describing instances of autoinflation of breast implants. Utilizing Medline, a total of 18 articles and 45 unique patients were identified all affected by autoinflating mammary implants. A table was constructed utilizing Microsoft Excel 2002 (Washington, USA) containing all pertinent demographic information, as well as specifics concerning each patient’s presentation, surgical history, implant type, date of insertion, initial fill volume, and final expanded volume. In an attempt to further investigate the prevalence of this phenomenon, an online survey was conducted of 3660 ASPS members utilizing the Survey Monkey software, (www.SurveyMonkey.com).
RESULTS - A total of 45 unique patients were identified in the literature. The average age of the 21 patients with known ages at the time of explantation was 41.5 years. The average time the implant was invivo of the 44 known patients (calculated from time of insertion to time of explantation) was 3.76 years with a range of 5 days to 23 years. Implant locations were submuscular, subfascial, and subglandular, with a fairly even distribution between left and right. 6.7% were filled with silicone, 77.8% saline, 13.3% hydrogel, and 2.2% unspecified fill material. 75.6% had textured surfaced, 6.7% smooth, and 17.8% unspecified. For the 20 patients with known pre-operative fill volumes and post-explantation volumes, the average volume increase was 59.9%. The survey, sent to 3660 ASPS members, yielded an 11% response rate, identifying 39 additional cases of spontaneous autoinflation, or roughly 10% of the response group.
CONCLUSION - The rare phenomenon of spontaneous autoinflation of breast implants has proven as elusive to document as it has to uncover the underlying mechanism. A possible explanation postulated in the face of an intact outer shell, and functioning, non-leaking valve is that the implant was filled with hypertonic solution causing fluid from the surrounding tissue to enter along an osmotic gradient. If we invoke this possible mechanism, we have no concrete explanation for the amount of elapsed time noted in some cases between implant insertion and autoinflation; some upwards of 14 years as in our patient’s case. We speculate that the phenomenon of spontaneous autoinflation is underreported in the literature, and should be kept in the differential diagnosis as one attempts to uncover the cause of unilateral post-implantation increase in breast size.