a minimal incision maximal access system allows for maximum desirable exposure along with maximum access to the operative field utilizing a minimum incision as small as the metrx and endius systems . instead of multiple insertions of dilating tubes the design is a streamlined single entry device to avoid repetitive skin surface entry . the system offers the capability to expand to optimum exposure size for the surgery utilizing hinged bi - hemispherical or oval working tubes applied over an introducer obturator which is controllably dilated to slowly separate muscle tissue . deeper end working and visualization areas with maximum proximal access and work dimensions are provided to makes the operative procedure safer in application and shorten the surgeons &# 39 ; s learning curve because it most closely approximates the ability to use open microdiskectomy techniques . a dual frame system enables full or partial spreading of a working tube set , while an open frame facilitates a four point retraction system .