** Canadian robotic surgical system maker’s U.S-listed shares fall 7.4 pct to $3.5 premarket
** Tuesday after market, Titan said it has filed statements with regulators for an offering of units and expects to raise between $20 mln and $25 mln
** Each unit will comprise one common share of the company and one common share purchase warrant
** Titan says it will use the proceeds to fund development work for its Sport surgical system and towards working capital and other general purposes
** U.S. and Canadian shares of the company fell about 56 pct in the past 12 months (Reporting by Manas Mishra in Bengaluru)
