US Patent 7033319 Abdominal retractor

An adjustable retractor is disclosed comprising an inner ring, an outer ring spaced from the inner ring, and an elongate sleeve open at opposite ends. The sleeve is provided and extends between the inner and outer rings and is connected at the opposite ends to the rings. The outer ring is provided with a pre-loaded rotational torque to assist with rotation of the outer ring about its central axis to roll the sleeve about the outer ring to adjust sleeve length. An obstetrics version of the retractor may be used for caesarean sections. A hydraulically controlled retractor includes fluid channels in the inner and outer rings that may be dilated by injection of an appropriate fluid.