Accessory device, a patient immobilization system, and a method of forming a patient immobilization system

1. An accessory device configured to position a patient relative to an immobilization device including a low temperature thermoplastic sheet, the accessory device comprising:

a patient fixation portion configured for fixation on or insertion into the patient during use; and

a lock portion extending distally from the patient fixation portion generally along a lock portion axis;

wherein the accessory device is configured to be engaged by and to contact a proximal surface of the low temperature thermoplastic sheet by forming the proximal surface of the low temperature thermoplastic sheet around the lock portion of the accessory device, such that the proximal surface of the low temperature thermoplastic sheet conforms to the lock portion and when engaged prevents unintended separation of the accessory device from the low temperature thermoplastic sheet during use;

wherein when engaged, the lock portion does not penetrate the low temperature thermoplastic sheet from the proximal surface of the low temperature thermoplastic sheet to a distal surface of the low temperature thermoplastic sheet;

wherein the proximal surface of the low temperature thermoplastic sheet is positionable proximal the patient and the distal surface of the low temperature thermoplastic sheet is opposite from the proximal surface; and

wherein the accessory device has an air passage such that air may pass through the accessory device.

2. The accessory device according to claim 1 , wherein the lock portion includes at least one projection extending transverse to the lock portion axis.

3. The accessory device according to claim 2 , wherein the at least one projection comprises a configuration selected from the group consisting of a T-shape, a Y-shape, a X-shape, a fan shape, a bow-tie shape, a ring shape, an oblong shape, a rhombus shape, a rectangle, and a circle.

4. The accessory device according to claim 2 , wherein the at least one projection extends in a transverse direction.

5. The accessory device according to claim 2 , wherein the at least one projection extends in a superior/inferior direction.

6. The accessory device according to claim 1 , wherein the patient fixation portion comprises a mouthpiece.

7. The accessory device according to claim 6 , wherein the mouthpiece has a U-shaped configuration.

8. The accessory device according to claim 6 , wherein the air passage is fluidly connected to a palate vacuum outlet.

9. The accessory device according to claim 1 , wherein the lock portion comprises an engaging end portion extending from the patient fixation portion, the engaging end portion having a variable cross-sectional area along and orthogonal to the lock portion axis.

10. The accessory device according to claim 9 , wherein the lock portion further comprises a stem portion extending from the patient fixation portion to the engaging end portion.

11. The accessory device according to claim 1 , wherein the lock portion defines at least one ridge.

12. The accessory device according to claim 1 , wherein the lock portion defines at least one notch.

13. The accessory device according to claim 1 , wherein the lock portion defines at least one hole.

14. The accessory device according to claim 1 further comprising an adhesive coating applied to a surface of the engaging end portion.

15. The accessory device according to claim 1 comprising a plurality of lock portions extending from the patient fixation portion.

16. The accessory device according to claim 1 , wherein the accessory device is a single piece.

17. The accessory device according to claim 1 , wherein the accessory device further comprises at least one tongue or epiglottis blocking feature.

18. The accessory device according to claim 1 , comprising plural air passages such that air may pass through the accessory device.