Gas-tight seal assemblies for use during minimally invasive surgery include various aspects. A wiper seal includes a sealing portion and a surrounding flex portion. Upper and lower faces of the sealing portions are angled with reference to an inserted instrument, the upper face's angle being more acute with reference to the instrument's shaft than the lower face's angle. The flex portion is corrugated, support ribs are in one or more corrugation grooves, and the support ribs allow the groove to easily collapse but resist the groove widening. The support ribs also prevent the sealing portion from inverting. An instrument insertion guide is positioned over the sealing portion and moves laterally with the sealing portion. A latch piece removably secures the seal assembly to a cannula. An anti-inversion piece prevents the wiper seal from inverting when an instrument is withdrawn. An assembly may include various combinations of the seal assembly, a cannula, a surgical instrument, an obturator, an endoscope, and a teleoperated medical device. The seal assembly may rotate within a cannula. The seal assembly may be used during manual or teleoperated surgery.