A preliminary prospective study of the usefulness of a magnetic endoscope locating device during colonoscopy

Although magnetic endoscope imaging of the colonoscope via the Endoscope Positioning Detecting Unit (EPDU) has been studied to some extent in Europe, its application in the United States has been limited. The purposes of this study were to determine whether the technique enabled for accurate localization of the lesion and to determine if and how the device facilitated scope insertion and completion of the colonoscopic exam.

Outpatient colonoscopies using the EPDU were performed by three experienced surgical endoscopists over a 5-month period. A specialized scope with electromagnetic coils or a regular scope with a magnetic probe insert in the instrument channel was used for the duration of the examination to identify loops and localize pathology.

A total of 80 colonoscopies were performed with the device. In two patients, the probe insert was removed prior to completion of the procedure; thus, the total number of examinations included in the study was 78. The EPDU was used in conjunction with transillumination to estimate the location of polyps or cancers in the 33 patients (42%) in whom such lesions were found. In the four patients who subsequently underwent operation, the lesion's location as estimated by EPDU was verified. In regard to the usefulness of the device during insertion, the EPDU led to the discovery of loops and to the application of pressure that resulted in prompt completion of the examination in 28% of cases (deemed most useful). In 33% of cases, the device identified loops and led to the application of abdominal wall pressure and early position changes, thus facilitating the examination; however it did not lead to its immediate or rapid completion. In 39% of cases, the device was not required or used for insertion due to the simple nature of the examination.

The EPDU was accurate in estimating lesion location. The device also holds promise as an aid in the completion of difficult exams (about 30% of cases in this study).