Effectiveness of transcutaneous electrical nerve stimulation (TENS) for analgesia during biliary lithotripsy

The effectiveness of transcutaneous electrical nerve stimulation (TENS) in controlling pain during biliary extracorporeal shockwave lithotripsy (BESWL) was assessed in 100 patients with symptomatic gallbladder calculi. Patients were divided into four groups: TENS electrodes were placed on the back at cutaneous anesthesia sites and on the right leg and the gallbladder acupuncture site in groups A and B. Electrodes were "turned on" only in group A. In groups C and D, electrodes were placed only on the back at cutaneous dermatomes. Electrodes were "turned on" in group C only. The TENS unit was stimulated at the pulse rate of 60 to 100 microseconds and frequency of 80 to 125 Hz. Lithotripsy was performed with the Lithostar Plus overhead module. The differences in the amount of analgesic used and the pain experiences by the patients in all groups were not statistically significant. The proportion of patients requiring intravenous analgesia in each group was also not significantly different (72%, 80%, 68%, 76% in groups A to D, respectively). Thus, TENS did not help in reducing the amount of intravenous analgesia required or the average pain perceived by the patient during lithotripsy treatment.