Patent ID: 8579929

Claim:
An ophthalmic ultrasound surgical instrument, comprising: a surgical hand piece suited for phacoemulsification that includes a phacoemulsification needle that is hollow to define an aspiration passage and that distally terminates at a tip with a tip port, the needle being bent or angled; an infusion sleeve arranged radially outside of the needle so as to define therebetween an irrigation passage to channel irrigation flow, the infusion sleeve defining an irrigation opening arranged for the irrigation flow to exit the irrigation passage; a heat generation reduction structure configured to reduce heat present at the needle, wherein the heat generation reduction structure includes a bypass hole in the phacoemulsification needle, the bypass hole being configured to divert the irrigation flow from the irrigation passage to enter the aspiration passage under suction via the bypass hole while the port is obstructed and thereby prevent the irrigation flow from otherwise exiting through the irrigation opening; a horn with a distal section and a resonant section, the distal section being longer than the resonant section, the distal section and the resonant section each having a generally cylindrical shape, the distal section having a cross sectional area that is less than the cross sectional area of the resonant section, the horn coupled to the needle; and a driver configured to impart a twisting, rotative movement to the tip at an elevated resonant frequency sufficient to eliminate chatter otherwise present at lower resonant frequencies.