I don't want to just repeat what Lost Soul and Hypersmurf have been saying, but I do feel compelled to ask: why does the wound have to be retconned away? Why can't the PC both be wounded, and be functional, because the healing surge is interpreted, on that occasion of surging, as an act of will to overcome the pain?
EDIT: Apparently I'm repeating Mustrum Ridcully as well!
Because it strains my (and most likely my players') sense of immersion if someone gets wounded to within an inch of his life, then "overcomes the pain", then suffers the same fate again, then overcomes the pain again, and then gets even more wounds, overcoming them again. The mental picture is rather like the old "I took 20 arrows to the chest, but no worry, I still have HPs left, so I am fine". Some wounds you simply do not ignore for too long.
I am fine with "ignoring the pain" of an stab to the thigh for a single fight, but doing that for the rest of the day, without any treatment? And doing the same for the arrow to the side, the slash to the biceps, the dislocated shoulder and the broken femur?
As long as you call superficial cuts "wounds" it works, but once you enter actual serious wounds in your description - like when a wound drops a PC into negatives - and then a healing surge fixes them, I encounter problems. A smashed shoulder, a gut wound, a broken leg - those do not go away that easily just because you focus.
If I described such wounds, then my players would expect more serious consequences, barring the absence of magical healing, than a "and you ignore the pain and soldier on for the next week" handwave.
(And yes, IMC, all the swallowing critters usually die quite messily when a PC cuts himself free from their belly - none of that utterly stupid "muscle contractions close the hole".)