The feasibility and reliability of using circular electrode for sphincter of Oddi electromyography in anaesthetised rabbits

Abstract

Sphincter of Oddi manometry (SOM) is the gold standard for assessing sphincter of Oddi dysfunction (SOD), but is considered a diagnostic sensitivity of 30-80% and associated with significant complications of pancreatitis. Electromyography (EMG) of sphincter of Oddi (SO) using a circular electrode (CE) may be useful in improving diagnostic accuracy and reducing complications. To evaluate the feasibility and reliability of the CE, we record myoelectric activity of SO in rabbits using the CE to compare with the traditional needle electrode (NE). The CE was prepared using a double-channel biogel catheter with two silver rings at the head of the catheter. The CE was then inserted into the lumen of the SO through the duodenal papilla, and myoelectric activity was recorded in the SO in 30 rabbits. An EMG recorded using an NE was performed at the same time, when the SO was in basal state, after injection of cholecystokinin and N-butylscopolamine bromide. Electromyographs recorded by the two methods were then evaluated. Satisfactory SO EMGs were acquired using the CE without any injury. Simultaneous recording revealed a very similar traces and one-to-one correspondence of SO spike bursts (SOSB). Linear regression analysis showed a significant direct correlation between the two methods for SOSB duration and amplitude. The results suggested that CE was comparable with NE in terms of recording efficacy. The CE also has advantages of easy fixation, accurate localisation, broad applicability and ease of achieving satisfactory outcomes without trauma, compared with the NE.

Reduced myoelectric activity in the sphincter of Oddi in a new model of chronic cholangitis in rabbits: an in vivo and in vitro study

“…Details of the myoelectric system have been described elsewhere 22 . In brief, parameters of multi‐channel physiological recording system (RM6240; Chengdu Instrument Factory, Chengdu, China) included time constant of 1 s, velocity at 1 s div −1 , sensitivity at 200 μV, high‐cut‐off frequency at 30 Hz and high‐pass filter at 10 Hz.…”

“…The circular electrode was made of a double‐channel biogel catheter (0.12 cm in diameter and 10 cm in length) (Shandong Freda Medical Device Co, Ltd, Jinan, China). Two isolated silver rings (0.2 cm in width; 0.16 cm OD; 0.04 cm in thickness) encircled the head of catheter, with approximately 0.3 cm distance between two rings 22 …”

“…21 tried to use circular electrodes to simultaneously record the electrical and mechanical activity of SO during endoscopic retrograde cholangiopancreatography, but the result was unsatisfactory. In our previous study, we successfully modified a circular electrode and adjusted the recording parameters to record the electrical activity of SO in rabbits 22 …”