The effect of transcutaneous nerve stimulation on intraductal biliary pressure in post-cholecystectomy patients with T-drainage

OBJECTIVETo evaluate the effects of transcutaneous electrical nerve stimulation (TENS) on intraductal biliary pressure (IDP) in basal conditions and after intravenous morphine and oral meal stimulation. DESIGN AND METHODSFifteen patients (5 male, 10 female) aged 31–83 years (mean 61.5 ± 13.7 years) with prior cholecystectomy and residual in situ T-tube were examined. Final radiographs excluded any organic abnormalities. The study consisted of three sessions. On the first day (session 1), after the initial manometric intraductal pressure was measured for 15 min, TENS (using a PRO-TENS pocket stimulator) was applied for 15 min. Measurement was continued for 15 min after termination of TENS. The measurement was performed using a water-perfused manometry system (Synectics Medical, Stockholm, Sweden) by a triple-channel manometric catheter inserted into the common bile duct through a T-drain. On the following day (session 2), the protocol was similar except that, after basal IDP measurement, morphine hydrochloride 0.08 mg/kg was injected intravenously 10 min before TENS. On the third day (session 3), after basal measurements were taken, patients were given a standard test meal and the IDP was recorded continuously for 45 min. To estimate the effects of the stimuli applied, absolute intraductal pressure changes were analysed. RESULTSIn session 1, TENS reduced basal IDP in all patients by a mean of 3.95 ± 1.6 mmHg. In 13 patients, 15 min after cessation of TENS a further decrease in IDP was observed. In two patients, termination of TENS was followed by a rebound increase in IDP; however, it did not reach the initial value (mean total decrease 5.05 ± 2.25 mmHg). In session 2, administration of morphine produced an evident increase in IDP in all subjects by 6.9 ± 2.7 mmHg. TENS decreased IDP in 13 patients. In two patients, TENS initially failed to lower elevated pressure, but it appeared several minutes after the end of stimulation. In 13 patients, the final IDP values were lower than the baseline pressures. In session 3, after administration of a test meal, IDP decreased within 30–40 min by a mean of 4.89 ± 1.29 mmHg. CONCLUSIONSTENS decreased basal as well as elevated IDP in the majority of the T-drain patients studied. The effect of TENS persisted after its termination. Elevated IDP is believed to be responsible for pain in patients with sphincter of Oddi dysfunction (SOD). Therefore, we think that TENS can be used effectively and safely as an optional therapeu