If repairs are done by the original equipment manufacturer, there is a reasonable assurance that products will be returned with original parts and will meet original specifications. If repairs are done by a third party, the same may not be true. Typically, OEMs do not share specifications. Third-party companies will attempt to reverse engineer the devices, but without access to the original engineering documents, the quality of repairs can be negatively affected.

Ninety percent of the working components of an endoscope are internal. Full inspection is not possible without disassembly. This is unfortunate because changes can be made to the lens or light fiber systems without the customer’s knowledge.

The surface of this repaired light guide post taper shows exposed copper and the pitted surface of the light fibers.

Without access to original specifications or original parts, third parties may use generic lenses and fibers. Any flaws in the imaging system are magnified by repeated repairs, and will eventually affect image quality. Light fiber alterations can result in less light being delivered to the surgical site. Because the endoscope acts as the eye of the surgeon, any degradation of the light output or image quality can hamper the surgeon’s ability to perform his work and may ultimately place the patient at risk.

Given this, the most practical alternative to disassembly for assessing repair quality is to compare the repaired endoscope to an original for indications of the overall quality of the repair. The following are key inspection points for customers assessing typical repairs performed by third parties:

• Assess image quality and light output quality by comparing the repaired scope to a new endoscope of the same model. To do this, compare the light fibers by pointing the distal end toward a room light and examine the light guide post for color, brightness and broken fibers that appear as black spots. If possible, connect the endoscopes to a video system and examine the color, shape and intensity of the light output by placing the light source on low to medium power and shining the light against a white paper approximately 8 cm to 15 cm away. As endoscopes age or as a result of improper light fiber repair, the shape of the light pattern often may change and the color of the light output may become yellow. After inspecting for light quality, inspect the image using a monitor to compare and contrast the original endoscope to the repaired one. Examine the image by viewing typed print on a white background from 8 cm to 15 cm away.

The block of an endoscope with considerable wear after repeated use and repair, as well as a filled pin hole.

• Inspect the workmanship. Compare the endoscope to an original and note any differences in the materials used. Any repair to the lens system or light fiber system requires the endoscope to be disassembled. This repair requires a technician to heat the connection of the housing body and the eyepiece to very high temperatures with either a torch or heat gun. Without proper specifications or training, it is very easy to damage components during this process, which can lead to difficulty in resealing the endoscope after repairs have been made. Any problems encountered while resealing the scope can result in leaks. Look for examples of epoxy leaking from around joints as well as joints where epoxy is used in place of a weld.

• Look for evidence of holes that have been drilled in the block and then filled with epoxy. This is done by third parties to allow insertion of a pin to prevent damage to the light fibers during disassembly. This creates another hole in the housing that, while small, is another potential area for leaks if an adequate seal is not created or if the epoxy is dislodged.

• Examine the light guide post for modifications. Most often, light guide posts and fibers are not changed during a repair process. This results in aging fibers that emit less light over time. If work is done on the light guide post, (grinding/polishing/replacement) it often results in modification to the original specifications. Any changes to dimensions, reflectivity, etc., in this area can cause issues with light throughput and heat. In extreme cases, changes can cause excessive heat to build up in that space, causing damage to the light fibers, and loss of light transmission.

Comparison of 2 distal tips—a KARL STORZ shaft with original tip geometry (bottom) and a third-party tip (top) the shape of which has been altered significantly by grinding and polishing.

• If work was performed on the sapphire crystal window at the distal end of the endoscope, changes likely have been made to the seal that secures the window. On original Karl Storz endoscopes, the window is welded in place. This weld is critical because the endoscope can leak if it is damaged. Third parties often glue this joint rather than welding it when the crystal is replaced. In addition, if the crystal is scratched, third parties will often grind the distal end, which can result in damage to the weld. If the weld fails, the crystal window can fall out, allowing the entire lens train to also fall out of the endoscope.

The bottom line is that the best way for a customer to ensure endoscope quality is to rely on the OEM for repairs or exchanges. If a third party is used, the customer is advised to assess the quality of a repaired endoscope through comparison with an original endoscope of the same model and allow the OEM to evaluate the quality of the repair work with you. They can perform both internal and external evaluations and tell you if you are receiving a quality repair or not.

Gregg Agoston is associate director, Karl Storz Services.

Introduction and Vendor Chart

Optimal Care & Handling of Scopes