What is the smallest sized silicone/saline implant available?

Hello and thank you for your question.  The
best advice you can receive is from an in-person consultation.  Some implant manufacturers produce in the 150cc range.   The size, profile, and shape of the
implant is based on your desired breast size/shape, your chest wall
measurements, and soft tissue quality.  This decision should
be based on a detailed discussion with equal input from both you
and your surgeon.   Make sure you specifically look
at before and after pictures of real patients who have had this surgery
performed by your surgeon and evaluate their results.   The most
important aspect is to find a surgeon you are comfortable with. I recommend
that you seek consultation with a qualified board-certified plastic surgeon who
can evaluate you in person.
Best wishes and good luck.
Richard G. Reish, M.D.  FACS
Harvard-trained plastic surgeon

The smallest implant available is a 100ccIf you are looking for an even smaller increase in size you may consider fat grafting with external expansion or internal tissue plication