A case report of laparoscopic cholecystectomy using a Wolf 0° laparoscope

1. Fault Analysis

The failure of this wolf 0° endoscope is that the image is blurry and the field of view is very dark. Check both ends of the endoscope for dirt, wipe both ends of the lens with an alcohol swab and observe again. The fault remains. A noticeable dent is visible on the outer surface of the endoscope tube. First, connect the cold light source and observe that the illumination fiber is not broken, confirming that the unclear image is not caused by the illumination system. Next, gently shake the body of the scope and a clear sound can be heard, indicating that the internal parts are loose. This indicates that the internal optical system (rod lens and spacer ring) is damaged and needs to be disassembled for repair.

2. Fault Handling

Because the exterior of the endoscope is made of all stainless steel and is particularly precise, disassembly is quite difficult. Before disassembly, you must carefully examine the general structure of the endoscope, find the correct interface, and then proceed to avoid damaging the illumination system.

First, use an alcohol lamp to heat and deglaze the eyepiece end. Then, use a special tool (bronze bushing) and use a three-jaw chuck to clamp the bronze bushing and eyepiece cover so that the eyepiece cover can be removed.

Because many endoscopes have a lot of glue inside, opening them requires more patience, and repeated carefulness is essential. After removing the eyepiece cover, the next step is to remove the eyepiece end, but it should not be blindly disassembled. The optical structure of each endoscope is different, and the matching and position of each part must be clearly understood before disassembly. This is also done by heating with an alcohol lamp. After reaching a certain temperature, use a vise grip to clamp it and then use heavy-duty pliers to clamp the metal eyepiece end and rotate it in opposite directions to loosen the glue on top so that the eyepiece can be removed, and then the rod lens can be guided out.

After disassembling the endoscope, the method of checking one by one is adopted. First, the eyepiece is not damaged, and then the front rod lens is analyzed. It is particularly important to note that removing the rod lens is the key to the repair. The direction and number of each rod lens must be marked, as each lens has its own installation tolerance; otherwise, disrupting them will affect the optical imaging. When removing the3first rod lens, it was found that one end of the rod lens was severely fractured, and its fragments had been squeezed into the spacer ring. The cause of the fault was found; the damage to the rod lens affected the optical imaging, and the rod lens needed to be replaced. After finding the matching rod lens and installing it, observe the imaging effect. The matching of the optical system is very important; the rod lens is used for image inversion and achromatism, as well as bonding lenses, and when observing objects, it produces an inverted image. The purpose is to make this rod lens conform to the imaging of the entire optical system. After repeated adjustments, the optical imaging meets the requirements. This rod lens can be used, but the imaging quality is still relatively poor, and the entire optical system needs to be cleaned. Use degreasing cotton, alcohol, and an air blower to clean and wipe the optical lenses and hard tube in sequence. Finally, install and adjust according to the direction. After observing the image, a clear and bright effect is achieved.

3. Post-Repair Inspection

The repaired endoscope needs to be dried first, then glued, and finally image printing and leak detection are performed to check that the image is normal. The fault handling work is complete.

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