INTRODUCTION
urolithiasis, pain
URETER, ANESTHESIA COMPLICATIONS, UROLITHIASIS
Despite the benefits of spinal anesthesia and the preference of anesthesiologists for this technique, it is less accepted by urologists due to the proximity of the stone place in the ureter and the possibility of pain, restlessness, and occasional movements of the patient during surgery. The current study investigated the success of bupivacaine plus intrathecal fentanyl in patients undergoing transurethral lithotripsy (TUL). In this randomized clinical trial, from April 2021 to September 2021, 54 patients with proximal urolithiasis candidates for TUL were enrolled. Patients were randomly categorized into two groups: group A received bupivacaine 10 mg and 0.5 ml of normal saline, while group B received bupivacaine 10 mg with 0.5 ml (25µg) of intrathecal fentanyl. According to our findings, about 74% of the patients were men, and the mean age of the patients was 66.14±22.46 years. The onset time of the sensory block, sensory block level, pain score, degree of relaxation, depth of the motor block, occurrence of anesthesia complications, oxygen saturation, and mean arterial blood pressure were not significantly different between the two groups. However, the duration of the motor block in group B was longer than in group A (p<0.001). Also, retropulsion was observed only in five patients (18.5%) in group A, significantly higher than in group B (p=0.019). Bupivacaine with fentanyl 25µg provided adequate spinal anesthesia with lower retropulsion in patients with urolithiasis who are candidates for TUL.Spinal anesthesia (SA) is a safe and straightforward technique that is most commonly used for surgery of the abdominal and lower extremity [Despite the clinical benefits of SA and its widespread use, urologists are unsure about using it in transurethral surgeries due to the possibility of patient movement, restlessness, and subsequent insufficient control over the procedure. However, there is an apparent increase in demand for SA in urological surgeries and even in transurethral procedures because of fewer postoperative side effects. The significance of understanding the pharmacology of new adjunctive drugs in SA underscores the relevance of this study in addressing these concerns. The current investigation evaluated the effects of intrathecal fentanyl in co-administration with bupivacaine during TUL under spinal anesthesia, focusing on patient comfort, surgical success, and possible side effects.