Background: Unilateral spinal anesthesia is often accompanied by technical difficulties in implementation, multiple puncture attempts, unsuccessful punctures, and, as a result, insufficient anesthesia, along with various complications associated with a dural puncture. Objectives: This work compares the efficacy and safety of conventional Unilateral Spinal Anesthesia (USpA) and unilateral spinal anesthesia with electrical nerve stimulation (USpA+ENS). Methods: A total of 134 patients with an upcoming vascular surgery on one lower extremity were randomly assigned to two groups. All the patients were positioned with the operated limb below and used 7.5 mg of Bupivacaine-Spinal®. In the UsPA group, anesthesia was performed according to the standard technique. In the USpA+ENS group, electrical nerve stimulation was additionally used. Primary outcomes were the presence or absence of post-dural puncture headache (PDPH), number of puncture attempts, lateralization, and anesthesia adequacy. Secondary outcomes were intraoperative pain scores, the presence or absence of nausea and vomiting, and the need for hemodynamics correction. Results: The frequency of puncture complications was sufficiently lower in the USpA+ENS group than in the UsPA group. The local anesthetic solution distribution, pain score indicators, and secondary outcomes were comparable in both groups with a slight difference. Conclusions: We showed that USpA+ENS reduces the incidence of puncture complications and improves the quality of anesthesia and adherence of both patients and anesthesiologists to the unilateral spinal anesthesia technique.