Usefulness in NOTES of an intra-abdominal antifogging wireless charge-coupled device (CCD) camera with pantograph-type needle unit for placement to the intra-abdominal wall

Background In natural orifice transluminal endoscopic surgery (NOTES), the endoscope has the disadvantages of an unstable visual field and wide blind space. We developed a compact charge-coupled device (CCD) camera unit that can be transgastrointestinally placed in the abdominal cavity. Methods The requisites for a wireless CCD camera unit for use in NOTES have been cited as: monitoring performance, fixation to the abdominal wall, attitude control, and antifogging functionality. Models to meet these requisites were prepared to assess their performance. The monitor had a CCD with dimensions of 7 x 7 x 7 mm and resolution of 410,000 pixels. The unit had a structure that allowed its attachment to the endoscope apex when placed to the abdominal wall. The abdominal wall fixation unit was equipped with a pantograph-type needle structure that was easily activated and retained by changing the polarity of an electromagnetic force. The pantograph-type needle head was designed to rotate by 360 degrees as an attitude-control mechanism, and both the pantograph and attitude-control mechanisms enabled attitude control in horizontal and vertical directions by a magnetic force applied from outside the body. Fogging was prevented by a vibration mechanism that physically cleaned the CCD lens surface and by titanium dioxide coating of the lens surface. Results The CCD camera unit was confirmed to have sufficient performance as an auxiliary monitor for endoscopy in terms of visual field and resolution. The pantograph-type needle structure successfully completed fixation of the CCD camera unit to the abdominal wall. Unit attitude was easily controlled, and fogging could be addressed by water supply before insertion of the CCD camera unit into the peritoneal cavity. Conclusions The wireless CCD camera unit was verified to function as an effective second eye in NOTES by using the described mechanisms and antifogging coating.