A surgical instrument includes a housing and an elongated shaft extending distally therefrom. The elongated shaft includes a proximal portion, a distal portion and a flexible portion supported therebetween. The flexible portion permits pivotal movement of the distal portion of the elongated shaft and an end effector supported thereon. A locking mechanism is operatively associated with the flexible portion of the elongated shaft to selectively impede pivotal motion of the distal portion. The locking mechanism includes a locking coil disposed about an axis defined by the flexible portion of the elongated shaft. A distal end of the locking coil is coupled to the distal portion of the elongated shaft, and a proximal end of the locking coil is rotatable about the longitudinal axis to laterally approximate the locking coil to flexible portion, and thus frictionally engage the flexible portion of the elongated shaft to selectively impede articulating motion thereof.