- 2025-12-01
- BMC anesthesiology 26(1)
- Yuekun Liu
- Haiyan Li
- Jinqin Bi
- Chengrun Lu
- Wenchao Li
- Xiangguo Chai
- Pei Ye
- Qian Zhang
- Guangping Qian
- Zhihai Li
- Hongjiang Zhang
Study Design
- Type
- Randomized Controlled Trial (RCT)
- Sample size
- n = 46
- Population
- 46 patients who underwent total knee arthroplasty
- Methods
- randomly divided into L5-S1 (group A) and L3-4 (group B) with 23 cases each; paramedian approach spinal anesthesia under in-plane real-time ultrasound guidance; 15mg of 0.75% bupivacaine (0.75% bupivacaine 2ml + cerebrospinal fluid 1ml) injected
- Blinding
- Single-blind
Background
Spinal anesthesia at L5-S1 is rarely used and many characteristics of L5-S1 spinal anesthesia are not well-documented in the literature. Objective：The primary outcome measure was to compare the highest sensory block level between ultrasound guided L3-4 and L5-S1 spinal anesthesia. Secondary outcomes were the time required to reach the highest sensory block level, the incisional sensory block recovery time, the mean arterial pressure (MAP), heart rate and their changes at each time point during the operation, the operative time, the satisfaction rate of anesthesia, the use of vasopressors, and the incidence of post-operative complications.Methods
46 patients who underwent total knee arthroplasty from December 2023 to December 2024 were randomly divided into L5-S1 (group A) and L3-4 (group B) with 23 cases each. In statistical analysis, 41 cases were used. 2 patients were excluded due to missing data in group A. In group B, 1 patient was converted to general anesthesia due to inability to perform spinal puncture because of difficult anatomy, 1 patient received excessive local anesthetic injection at the surgical site, and 1 patient had missing data. All patients were treated with paramedian approach spinal anesthesia under in-plane real-time ultrasound guidance. After successful puncture, 15mg of 0.75% bupivacaine (0.75% bupivacaine 2ml + cerebrospinal fluid 1ml) was injected. A third party recorded all primary and secondary outcomes.Results
In the L5-S1 group, the highest sensory block level was lower and the total number of spinal segments blocked were fewer, the time to reach highest sensory block level was longer, and the recovery time of incisional sensory block was longer (P < 0.001). The decrease in MAP was smaller, and the use of vasopressors was less frequent (P < 0.05), with greater hemodynamic stability in the L5-S1 group. The satisfaction rate of anesthesia in both groups was 100%.Conclusion
Under real-time ultrasound guidance, L5-S1spinal anesthesia has many benefits compared to L3-L4 spinal anesthesia.Trial registration
This trial was registered on July 21, 2025 at the Chinese Clinical Trial center (No. ChiCTR2500106275). Retrospectively registered.