A trocar seal must allow a surgical instrument to pass through it cleanly and easily. Sometimes this is accomplished by the design of the assembly. Sometimes, as with a duckbill seal, it is accomplished by cutting or slitting through the rubber in the right location. It is challenging to properly and completely slit polyisoprene duckbill seals so they can perform as required. The slit must be perfectly sized and centered to facilitate instrument insertion and prevent damaging the seal and seal walls.

Ironically, polyisoprene rubber, a soft and pliable material, can be difficult to accurately and cleanly slit. Elongation and elasticity of the material (the very qualities desired) are also the problems. As the slitting blade compresses the material, its elasticity makes it move out of the way. Because of this, the slit is often inconsistent and not completely cut through. If the seal openings aren't slit properly, surgeons can't insert instruments through the opening and into the body.

One way to achieve accurate slitting is to use an automated process with a vision system that confirms the size, location, and quality of the slit. Critical to this process is the design and use of steel-rule dies mounted on mandrels. The dies perform the high-speed, automated slitting operation of the duckbill seal device.

Proper centering of the slot in the end of the seal is essential. To verify this, when the mandrel table rotates out of the slitting station, an automated vision system provides verification that the slit is sized, positioned, and centered correctly. The vision system ensures that the device can function properly at the time of use.

Endoscopic surgeries are trending toward even-less-invasive procedures, such as single-port entry (shown here) and natural orifice entries.

Proper centering of the slot in the end of the seal is essential. To verify this, when the mandrel table rotates out of the slitting station, an automated vision system provides verification that the slit is sized, positioned, and centered correctly. The vision system ensures that the device can function properly at the time of use.

Design

Although seals constitute a small part of a trocar device, they are often the most important component in the product. Accordingly, the trocar seal design process, as well as the actual seal design itself, may be quite complex. Seals must be carefully designed, and those designs must be tested to provide documented evidence of their performance; that evidence must be subsequently confirmed by process validation.

All sealing applications fall into one of three different groups. These applications are as follows:

Applications involving no movement (static).

• Applications involving linear motion (reciprocating).

• Applications involving high-speed rotation (rotary).