Needle valves are a small (usually 1 inch or less), simple, and rugged means of throttling and shutting off extremely high pressures compared with other valves.

Methods (1)To compare the drainage speed of the improved EV needle and percutaneous transhepatic catheterizde drainage(PTCD) case needle in water and anti coagulation pigs blood.

Results. Needle punctures with full or half penetration caused significant disc space narrowing and progressive histologic changes of degeneration as early as 1 and 2 weeks after injury, respectively.