gms | German Medical Science

Objective: The Endoscopic technique has revolutionized transnasal skull base surgery over the last decades. However, endoscopes are still missing stereoscopic vision or adequate resolution compared to the operating microscope. We evaluated a new 3D/HD endoscope for transnasal minimally invasive procedures and present our first laboratory as well as clinical experience.

Methods: The 3D/HD endoscope (Karl Storz, Tuttlingen/Germany) was evaluated for transnasal use on 5 dry skull specimens, 5 formaldehyde-fixed and 20 fresh cadavers. A variety of transnasal approaches (mono-nostril paraseptal, mono-nostril transethmoidal, combined mono-nostril and extended binostril) were carried out. Performance of the 3D/HD endoscope was compared to a standard 4 mm 2D/HD endoscope (Karl Storz, Tuttlingen/Germany) and rated as inferior, equal or superior. Handling, resolution of details and stereoscopic vision were systematically evaluated based on the following criteria: “Imaging”: recognition of details, color brilliance, illumination, image distortion, size and depth of field, fogging, 3D effect; “Usability”: handling, ergonomics, nausea, positioning, time for preparation, conflict with instruments. After evaluation in the laboratory, the endoscope was used intraoperatively as adjunct to the standard 2D/HD endoscope in 5 consecutive cases.

Results: The 3D/HD endoscope showed equal performance concerning size of field. 3D endoscope presented better recognition of details and color brilliance, less image distortion and larger depth of field. Stereoscopic 3D vision was found to be extremely helpful especially in deep seated regions. However, during the first nasal phase and in narrow anatomical situation, stereoscopic vision was partially disturbing because of inappropriate space or debris on the distal tip of the endoscope. Inferior performance was seen in fogging of the scope. Using the 3D endoscope resulted in reduced time of preparation and equal conflict with instruments, was associated with better handling and ergonomics. No fatigue or nausea was experienced. The results from the cadaveric studies were confirmed intraoperatively.

Conclusion: Overall, the new 4 mm 3D/HD endoscope was rated superior compared to the 2D/HD endoscope due to the stereoscopic vision, which was found to be extremely helpful especially in deep-seated locations. The pleasant stereoscopic vision might be especially helpful for neurosurgeons switching from microscopic to endoscopic surgery.