Cryosurgical instrument with redirected flow

1. A cryosurgical instrument comprising:

an external shaft with a cryotip at a distal end thereof;

a cryogen supply tube at a proximal end of the external shaft, the supply tube supplying a cryogen to the instrument;

a heat exchanger that cools a portion of the external shaft by directing the supplied cryogen against an inner surface of a portion of the external shaft and an inner surface of the cryotip and that guides exhausted cryogen away from the cryotip; and

a flow diverter disposed within the external shaft and between the cryogen supply tube and the heat exchanger, the flow diverter including

a first Y-configured passage with an inlet port at an upstream side of the diverter and

a second Y-configured passage with an inlet port at a downstream side of the diverter,

the first Y-configured passage receiving the supplied cryogen from the cryogen supply tube via the inlet port at the upstream side of the flow diverter and diverting the received cryogen to the heat exchanger in a downstream direction, and

the second Y-configured passage receiving exhausted cryogen via the inlet port at the downstream side of the flow diverter and directing the received exhausted cryogen to an exhaust tube in an upstream direction.

2. The cryosurgical instrument of claim 1 , wherein the heat exchanger includes an inner passage extending from an end thereof proximate to the inner surface of the cryotip to the downstream side of the flow diverter and through which the exhausted cryogen flows away from the cryotip, and wherein the inlet port of the second Y-configured passage is in fluid communication with the inner passage.

3. The cryosurgical instrument of claim 1 , wherein the heat exchanger comprises a plurality of grooves that spiral about a longitudinal axis of the heat exchanger and that open to portions of the inner surface of the external shaft.

4. The cryosurgical instrument of claim 1 , wherein said heat exchanger comprises a plurality of straight grooves that extend in parallel to a longitudinal axis of the heat exchanger.

5. The cryosurgical instrument of claim 1 , wherein the Y-configured passages are in a mutual 90-degree rotational relationship to one another.

6. The cryosurgical instrument of claim 1 , wherein said heat exchanger includes a spiral coil that spirals about a longitudinal axis of the cryosurgical instrument, is in contact with a portion of the inner surface of the external shaft,

forms one or more first spiral channels that, in cooperation with the external shaft, direct the flow of cryogen from the flow diverter to the cryotip, and

forms one or more second spiral channels that, in cooperation with the external shaft, direct the flow of exhausted cryogen from the cryotip to the flow diverter.

7. The cryosurgical instrument of claim 6 , further comprising a filling element that fills a volume inside of the spirals so as prevent the return cryogen to flowing in a retrograde manner.

8. The cryosurgical instrument of claim 1 , wherein the flow diverter is formed of a unitary workpiece.

9. A cryosurgical instrument comprising:

an external shaft with a cryotip at a distal end thereof;

a cryogen supply tube at a proximal end of the external shaft, the supply tube supplying a cryogen to the instrument;

a heat exchanger that cools a portion of the external shaft by directing the supplied cryogen against an inner surface of a portion of the external shaft and an inner surface of the cryotip and that guides exhausted cryogen away from the cryotip; and

a flow diverter disposed between the cryogen supply tube and the heat exchanger, the flow diverter including

a first Y-configured passage with an inlet port at an upstream side of the diverter and

a second Y-configured passage with an inlet port at a downstream side of the diverter,

the first Y-configured passage receiving the supplied cryogen from the cryogen supply tube via the inlet port at the upstream side of the flow diverter and diverting the received cryogen to the heat exchanger in a downstream direction, and the second T-configured passage receiving exhausted cryogen via the inlet port at the downstream side of the flow divert and directing the received exhausted cryogen to an exhaust tube in an upstream direction,

wherein the first Y-configured passage includes a single branch portion with one end at the inlet at the upstream side of the flow diverter and with an opposing end that splits into two branch portions, and wherein the second Y-configured passage includes a single branch portion with one end at the inlet at the downstream side of the flow diverter and with an opposing end that splits into two branch portions.

10. A cryosurgical instrument comprising:

an external shaft with a cryotip;

a heat exchanger that cools a portion of the external shaft and the cryotip when cryogen is received thereby; and

a flow diverter that receives a flow of cryogen, that splits the received flow of cryogen into two cryogen flows, and that delivers the split cryogen flows to the heat exchanger, the flow diverter including a Y-configured passage with an inlet port at an upstream side of the diverter that receives the flow of cryogen and two outlet ports at a downstream side of the diverter, and that is in fluid communication with the heat exchanger,

wherein the heat exchanger further comprises a pathway that guides exhausted cryogen away from the cryotip, and

wherein the flow diverter includes a second Y-configured passage with an inlet port at the downstream side of the diverter and that is in fluid communication with the pathway of the heat exchanger and two outlet ports at the upstream side of the diverter.

11. A cryosurgical instrument comprising:

an external shaft with an inner surface and a cryotip;

a heat exchanger that cools a portion of the external shaft and the cryotip when cryogen is received thereby, the heat exchanger includes an internal passageway that guides exhausted cryogen away from the cryotip; and

a flow diverter that receives a flow of cryogen, that splits the received flow of cryogen into two or more split cryogen flows, and that delivers the split cryogen flows to the heat exchanger, the flow diverter including a first passage with one or more inlet ports at an upstream side of the diverter that receive the flow of cryogen and two or more outlet ports at a downstream side of the diverter and in fluid communication with the heat exchanger,

wherein the heat exchanger is configured (i) to direct the delivered split flow of cryogen from the flow diverter to the cryotip and (ii) to cool the inner surface of the external shaft with the split flow as that flow travels to the cryotip, and

wherein the exhausted cryogen travels from the cryotip to the flow diverter only through the internal passageway of the heat exchanger.