Apparatus and method for phacoemulsification
A phacoemulsification needle having a hollow passageway terminates in a straight needle tip having a rectangular cross-sectional shape larger than the cross-sectional shape of the needle passageway. The tip is formed off-axis from the passageway, allowing the needle tip to move eccentrically when the needle is subjected to torsional or longitudinal vibratory motion. The inner and outer surfaces of the needle tip are roughened, as by sandblasting, to enhance the cutting effect of the tip when used with a non-longitudinal handpiece. The lip of each needle tip is polished to a high degree of smoothness and the edges of the tip are rounded to lessen the incidence of snags or cuts.
1. A phacoemulsification needle for use with a phacoemulsification handpiece, said needle comprising:
an elongate needle body having an outer surface, a cross-sectional shape, a proximal end and a distal end,
said needle body having a central needle axis extending along its length;
said needle body including only a single passageway extending through said needle body,
said passageway having a uniform cross-sectional size and shape and a central axis extending along its length;
a needle tip formed at said distal end,
said tip having a cross-sectional shape, an exterior surface and an inner surface,
said tip having a central longitudinal axis;
said tip axis and said passageway axis being offset and parallel such that said tip axis and said passageway axis do not coincide;
said exterior surface and said inner surface terminating at a lip;
said tip having a flaring shape that flares laterally outward in the direction toward said lip and terminating at said lip;
said tip having a mouth defined by said lip;
said tip cross-sectional shape being larger than said needle body cross-sectional shape; and
said tip cross-sectional shape being rectangular.
2. The phacoemulsification needle as recited in claim 1 wherein said lip is formed at an angle to said tip axis,
said lip having a lead portion and a trailing portion,
said lead portion of said lip extending longitudinally past said trailing portion.
3. The phacoemulsification needle as recited in claim 2 wherein at least a part of said lead portion is substantially coextensive with and lies in the same plane as said needle body outer surface.
4. The phacoemulsification needle as recited in claim 2 wherein at least a part of said trailing portion is substantially coextensive with and lies in the same plane as said needle body outer surface.
5. The phacoemulsification needle as recited in claim 1 wherein said lip is rounded and smoothed.
6. The phacoemulsification needle as recited in claim 1 wherein at least a portion of said outer surface proximate said distal end is roughened.
7. The phacoemulsification needle as recited in claim 1 wherein at least a portion of said inner surface proximate said distal end is roughened.
8. The phacoemulsification needle as recited in claim 1 wherein at least a portion of said outer surface proximate said distal end and at least a portion of said inner surface proximate said distal end is roughened.