A medical device comprising an outer housing (400) having a first wall (401) defining a first passage (402) with proximal and distal ends. A retraction housing (412) is slidably received in the first passage (402), the retraction housing (412) having proximal and distal ends and a wall with an interior surface wall defining a helical path (421). Part of the device includes a carriage (422) for releasably receiving a medical sharp (423), the carriage (422) slidably received in the distal end of the retraction housing (412). A latch means (428) is present for retaining the carriage (422) in a first position in the retraction housing (412). A follower (432) is connected to the carriage (422) and engaged with the helical path (421). A stored energy device (434) is connected to the follower (432) and the carriage (422). An actuation means (419) is operable to move the retraction housing (412) towards the distal end of the first passage (402), thereby to release the latch means (428) such that the stored energy device (434) is operable to drive the follower (432) along the helical path (421) and to retract the carriage (422) towards the proximal end of the retraction housing (412).
