Surgical fastener applying apparatus

1. A surgical fastener applying apparatus comprising:

an anvil half-section including a distal anvil portion and a proximal handle portion;

a cartridge receiving half-section defining an elongated channel member;

a stationary housing configured to be releasably supported within the elongated channel member of the cartridge receiving half-section, the stationary housing supporting firing components of the apparatus, the stationary housing dimensioned to releasably receive a single use loading unit, the stationary housing including a lockout structure that prevents full insertion of the single use loading unit into the stationary housing after the stationary housing is mounted in the cartridge receiving half-section.

2. The surgical fastener applying apparatus according to claim 1 , wherein the lockout structure is movable between a first position which prevents insertion of the single use loading unit into the stationary housing and a second position which allows insertion of the single use loading unit into the stationary housing, wherein the lockout structure is obstructed from moving from the first position to the second position when the stationary housing is supported within the elongated channel member.

3. The surgical fastener applying apparatus according to claim 2 , wherein the lockout structure includes a pair of sidewalls and a pair of flanges extending from the top of each sidewall.

4. The surgical fastener applying apparatus according to claim 3 , wherein when the lockout structure is in the first position, the sidewalls are substantially parallel with respect to each other, and the flanges define a first lateral dimension therebetween which is less than a lateral dimension of the single use loading unit.

5. The surgical fastener applying apparatus according to claim 3 , wherein when the lockout structure is in the second position, the sidewalls are inclined away from each other, and the flanges define a second lateral dimension therebetween which is larger than the lateral dimension of the single use loading unit.

6. The surgical fastener applying apparatus according to claim 3 , wherein the sidewalls of the central portion are connected to proximal and distal portions of the stationary housing by live hinges, such that the sidewalls of the central portion are pivotable with respect to the proximal and distal portions.

7. The surgical fastener applying apparatus according to claim 3 , wherein the lockout structure includes a bottom surface, and the sidewalls are hingedly attached to the bottom surface.

8. The surgical fastener applying apparatus according to claim 2 , wherein the lockout structure is positioned on a central portion of the stationary housing.

9. The surgical fastener applying apparatus according to claim 2 , wherein the lockout structure is normally in the first position.

10. The surgical fastener applying apparatus according to claim 1 , wherein the stationary housing, the firing components, and the single use loading unit form a single disposable unit when the single use loading unit is positioned within the stationary housing.

11. The surgical fastener applying apparatus according to claim 1 , wherein the firing components include a knife actuating bar, cam bar, guide block and slide block.

12. A surgical fastener applying apparatus comprising a reusable anvil half-section, a reusable cartridge receiving half-section, and a disposable firing assembly configured to be releasably supported within the cartridge receiving half section, the firing assembly including a disposable pusher assembly and a single use loading unit operably mountable to the pusher assembly, wherein the single use loading unit is not operably mountable to the pusher assembly if the pusher assembly is mounted in the cartridge receiving half section.

13. The surgical fastener applying apparatus according to claim 12 , further comprising first and second members extending from the pusher assembly and movable between a first position having a first gap dimensioned to receive the single use loading unit and a second position having a second gap smaller than the first gap and dimensioned to prevent insertion of the single use loading unit.

14. The surgical fastener applying apparatus according to claim 13 , wherein the first and second members extend from first and second sidewalls of the pusher assembly.

15. The surgical fastener applying apparatus according to claim 14 , wherein the first and second members are normally in the second position.

16. A disposable firing assembly for use with a surgical fastener applying apparatus comprising a disposable single use loading unit and a disposable pusher assembly, the pusher assembly insertable into a cartridge receiving half section of the fastener applying apparatus, the single use loading unit operably mountable to the pusher assembly, wherein the pusher assembly includes a lockout member movable from a first position preventing operable insertion of the single use loading unit therein and a second position enabling operable insertion of the single use loading unit therein.

17. The disposable firing assembly according to claim 16 , wherein the lockout member is normally in the first position and the lockout member is prevented from moving to the second position when the pusher assembly is mounted within the cartridge receiving half section.

18. The disposable firing assembly according to claim 16 , wherein the lockout member includes first and second members extending inwardly toward a longitudinal axis of the pusher assembly and movable to vary a gap therebetween.

19. The disposable firing assembly according to claim 16 , wherein the first and second members pivot from a first position substantially perpendicular to the longitudinal axis corresponding to the first position of the lockout member and a second position inclined with respect to the longitudinal axis corresponding to the second position of the lockout member.