Comparative study of ultrasound-guided paravertebral block versus intravenous tramadol for postoperative pain control in percutaneous nephrolithotomy.
Zehra HatipogluErsel GulecMediha TurktanVolkan IzolAtilla ArıdoganYasemin GunesDilek OzcengizPublished in: BMC anesthesiology (2018)
ClinicalTrials.gov, NCT02412930 , date of registration: March 27, 2015, retrospectively registered.