Instrument flushing system

1. A medical instrument comprising:

a shaft, a tool, a drive element, a housing assembly, and a fluid channel assembly;

the shaft comprising a proximal end and a distal end;

the tool being coupled to the distal end of the shaft;

the housing assembly comprising a fluid inlet and a mechanism configured to manipulate the drive element;

the fluid channel assembly comprising the proximal end of the shaft, a cap comprising an opening, and a guide comprising an opening;

the guide is secured on the cap, and the opening of the cap and the opening of the guide overlap to create a through hole that is smaller than the opening of the cap;

the drive element extending from the mechanism configured to manipulate the drive element, through the cap, into the shaft, and to the tool; and

the drive element fitting within the through hole to prevent leakage.

2. The medical instrument of claim 1 , wherein:

the housing assembly comprises a chassis;

the chassis comprises the fluid inlet, a surface, and opposing sidewalls, the opposing sidewalls extending from the surface of the chassis;

the fluid channel assembly comprises a trough between the fluid inlet and the cap; and

the trough comprises the surface and the opposing sidewalls of the chassis.

3. The medical instrument of claim 2 , wherein the cap comprises a flexible portion configured to seal against the sidewalls of the trough.

4. The medical instrument of claim 1 , wherein the guide comprises a resilient surface that redirects the drive element.

5. The medical instrument of claim 1 , wherein:

the drive element comprises a cable and a crimp on the cable;

the crimp is sized to fit through the opening of the cap and the opening of the guide; and

the through hole is sized to prevent the crimp on the cable from passing through the through hole.

6. The medical instrument of claim 1 , wherein at least one of the tool or the shaft further comprises one or more vents configured for fluid flow.

7. The medical instrument of claim 6 , wherein the one or more vents are configured to expose the drive element to cleaning from outside the shaft.

8. A method for cleaning a medical instrument, comprising:

receiving a cleaning fluid into a fluid channel assembly,

the fluid channel assembly comprising a proximal end of a shaft of the medical instrument, a cap, and a guide,

the cap comprising an opening,

the guide comprising an opening,

the guide being secured on the cap such that the opening of the cap and the opening of the guide overlap to create a through hole smaller than the opening of the cap, and

a drive element of the medical instrument extending through the through hole to prevent leakage of the cleaning fluid through the opening in the cap;

removing contaminants from inside the shaft by guiding the cleaning fluid to flow through the fluid channel assembly and through the shaft in a proximal-to-distal direction; and

draining the cleaning fluid out of the shaft through one or more exit holes near a distal end of the shaft.

9. The medical instrument of claim 1 , wherein the cap comprises a plurality of teardrop-shaped holes, the opening of the cap being one of the plurality of teardrop-shaped holes.

10. The medical instrument of claim 1 , wherein the cap encloses at least a portion of a fluid channel between the fluid inlet and the proximal end of the shaft.

11. The medical instrument of claim 1 , wherein the cap is plastic.

12. The medical instrument of claim 11 , wherein the plastic comprises polytetrafluoroethylene (PTFE) and polyether imide (PEI).

13. A medical instrument, comprising:

a shaft, a housing, a cap, a guide, and a cleaning channel;

the shaft comprising a proximal portion, a distal portion, and one or more exit holes defined in the distal portion of the shaft;

the housing supporting the proximal portion of the shaft, the housing comprising a fluid inlet and a trough;

the cap comprising an opening, and the cap being coupled to the trough to enclose a fluid channel between the fluid inlet and the proximal portion of the shaft;

the guide being secured on the cap, the guide comprising an opening;

the opening of the cap and the opening of the guide overlapping to create a through hole smaller than the opening of the cap and the opening of the guide; and

the cleaning channel being defined from the fluid inlet, through the fluid channel, through the shaft, and to the one or more exit holes.

14. The medical instrument of claim 13 , further comprising a drive element that extends through the through hole defined by the opening of the cap and the opening of the guide, and through the shaft.

15. The medical instrument of claim 13 , wherein:

the trough comprises opposing sidewalls; and

the cap comprises a flexible portion that seals against the opposing sidewalls of the trough.

16. The medical instrument claim 1 , wherein:

the medical instrument further comprises an O-ring; and

the O-ring is compressed between the guide and the housing assembly.

17. The medical instrument claim 16 , wherein the guide further comprises legs configured to contact the O-ring and provide openings for fluid communication between the fluid inlet and the shaft.

18. The medical instrument claim 1 , wherein:

the guide comprises a metal material; and

the guide redirects a path of the drive element between the mechanism configured to manipulate the drive element and the shaft.

19. The medical instrument claim 1 , wherein the opening of the guide comprises U-shaped notches.

20. The medical instrument claim 14 , wherein:

the guide comprises a metal material; and

the guide redirects a path of the drive element between the cap and the shaft.