New simple image overlay system using a tablet PC for pinpoint identification of the appropriate site for anastomosis in peripheral arterial reconstruction.

PURPOSE: To evaluate the accuracy and utility of a new image overlay system using a tablet PC for patients undergoing peripheral arterial reconstruction. METHODS: Eleven limbs treated with distal bypass surgery were studied. Three-dimensional images obtained by processing a preoperative contrast-enhanced computed tomography scan were superimposed onto the back-camera images of a tablet PC. We used this system to pinpoint a planned distal anastomotic site preoperatively and to make a precise incision directly above it during surgery. We used a branch artery near the distal anastomotic site as a reference point and the accuracy of the system was validated by comparing its results with the intraoperative findings. The precision of the system was also compared with that of a preoperative ultrasonographic examination. RESULTS: Both the image overlay system and ultrasonography (US) accurately identified the target branch artery in all except one limb. In that limb, which had a very small reference branch artery, preoperative US wrongly identified another branch, whereas the image overlay system located the target branch with an error of 10 mm. CONCLUSIONS: Our image overlay system was easy to use and allowed us to precisely identify a target artery preoperatively. Therefore, this system could be helpful for pinpointing the most accurate incision site during surgery.

A beam-splitter-type 3-D endoscope for front view and front-diagonal view images.

PURPOSE: In endoscopic surgery, surgeons must manipulate an endoscope inside the body cavity to observe a large field-of-view while estimating the distance between surgical instruments and the affected area by reference to the size or motion of the surgical instruments in 2-D endoscopic images on a monitor. Therefore, there is a risk of the endoscope or surgical instruments physically damaging body tissues. To overcome this problem, we developed a Ø7- mm 3-D endoscope that can switch between providing front and front-diagonal view 3-D images by simply rotating its sleeves. METHODS: This 3-D endoscope consists of a conventional 3-D endoscope and an outer and inner sleeve with a beam splitter and polarization plates. The beam splitter was used for visualizing both the front and front-diagonal view and was set at 25° to the outer sleeve's distal end in order to eliminate a blind spot common to both views. Polarization plates were used to avoid overlap of the two views. We measured signal-to-noise ratio (SNR), sharpness, chromatic aberration (CA), and viewing angle of this 3-D endoscope and evaluated its feasibility in vivo. RESULTS: Compared to the conventional 3-D endoscope, SNR and sharpness of this 3-D endoscope decreased by 20 and 7 %, respectively. No significant difference was found in CA. The viewing angle for both the front and front-diagonal views was about 50°. In the in vivo experiment, this 3-D endoscope can provide clear 3-D images of both views by simply rotating its inner sleeve. CONCLUSIONS: The developed 3-D endoscope can provide the front and front-diagonal view by simply rotating the inner sleeve, therefore the risk of damage to fragile body tissues can be significantly decreased.

3-D endoscope using a single CCD camera and pneumatic vibration mechanism.

BACKGROUND: During endoscopic surgical procedures, surgeons must manipulate an endoscope inside the body cavity to observe a surgical area while estimating the distance between that area and the surgical instruments by reference to a monitor on which the movement and size of the surgical instruments are displayed in 2-D endoscopic images. Therefore, there is a risk of the endoscope or instruments physically damaging body tissues. To overcome this problem, we developed a Ø5-mm, 3-D endoscope using a single 1/10-inch CCD camera and pneumatic vibration mechanism. METHODS: The 3-D endoscope proposed in this paper consists of an outer and inner sleeve, a 1/10-inch CCD camera attached to its distal end, and a pneumatic vibration mechanism attached to its proximal end. This endoscope can acquire left and right endoscopic images for stereovision in synchrony with the periodical motion generated by the vibration mechanism. We measured the displacement at the proximal and distal end of the 3-D endoscope simultaneously, and evaluated the feasibility of its use in vivo. RESULTS: The displacement at the distal end of the endoscope to which the CCD camera is attached was approximately ±0.25 mm. The timing when the displacement of the CCD camera was at maximal amplitude coincided with the timing when the displacement of its proximal end was at maximal amplitude. In the in vivo experiment, this 3-D endoscope can provide clear 3-D images of the surgical area. CONCLUSIONS: The developed 3-D endoscope that uses a single CCD camera and pneumatic vibration mechanism can successfully visualize internal organs inside the body even though the CCD camera is moved by the vibration. Therefore, the risk of damage to fragile body tissues can be significantly decreased.

A new, safer, controllable field-of-view endoscope avoiding movement inside body cavities.

One of the greatest difficulties in endoscopic surgery is the limited field-of-view (FOV) of endoscopes. During endoscopic manipulation in body cavities to expand the FOV, there is the risk of inadvertent damage to body tissues, nerves, and internal organs. The risk increases especially in surgery that is performed inside a very small cavity, or in which body tissues are very fragile. To overcome these issues, we developed a novel endoscope that can provide various FOVs without moving or bending the endoscope itself inside the body cavity and investigated the feasibility of using the new endoscope in vivo. A beam splitter was used to visualize both forward and side views, and two polarization plates and observation windows were used to avoid overlap of the two views. An endoscope having a 7-mm diameter was fabricated through which both views were clearly visualized in vivo. It took only 0.7s to change the FOV with high repeatability, with a maximum distance error of 2.8%. The new endoscope can provide forward and panoramic views without moving the endoscope; therefore, the risk of inadvertent damage to fragile body tissues can be significantly decreased.