Ultrasound-assisted modified paramedian approach vs. traditional paramedian approach for spinal anesthesia in lower limb surgery: a single-center randomized controlled trial.

STUDY OBJECTIVE: This randomized controlled trial aimed to determine whether an ultrasound-assisted modified paramedian approach could improve procedural outcomes compared with an ultrasound-assisted traditional paramedian approach for spinal anesthesia in patients undergoing lower limb surgery. DESIGN: Prospective, randomized, controlled clinical trial. SETTING: Operating rooms of Hebei Cangzhou Hospital of Integrated Traditional Chinese Medicine and Western Medicine, China. PATIENTS: A total of 116 patients aged 18-90 years, with a body mass index of 18-30 kg/m2 and ASA physical status I-III, scheduled for lower limb surgery requiring spinal anesthesia were enrolled. Patients with contraindications to spinal anesthesia, previous lumbar surgery, scoliosis, or pregnancy were excluded. INTERVENTIONS: Patients were randomly assigned in a 1:1 ratio using a computer-generated random allocation sequence with concealed allocation to receive either ultrasound-assisted traditional paramedian spinal anesthesia (Group C, n = 58) or ultrasound-assisted modified paramedian spinal anesthesia (Group M, n = 58). MAIN RESULTS: Compared with Group C, Group M required fewer needle passes to achieve successful cerebrospinal fluid (CSF) flow [median [IQR]: 1 [1-2] vs. 2 [1-3], P = 0.006] and demonstrated a higher first-pass success rate [37/58 [63.79%] vs. 25/58 [43.10%], P = 0.026]. Group M also showed a shorter duration of the spinal procedure [12.5 [9.0-20.0] s vs. 15.0 [10.0-32.25] s, P = 0.028] and shorter total procedure time [76.5 [65.0-89.25] s vs. 82.0 [72.0-112.75] s, P = 0.031]. The distribution of patient satisfaction scores differed between groups, with a higher proportion of patients reporting being "very satisfied" in Group M (87.93% vs. 70.69%, P = 0.040). The incidence of procedure-related and postoperative adverse events was comparable between groups, and no serious complications occurred. CONCLUSIONS: The ultrasound-assisted modified paramedian approach was associated with fewer needle passes, improved first-pass success, and higher patient satisfaction ratings compared with the traditional paramedian approach, while without increasing short-term procedure-related adverse events. Further multicenter studies are warranted to determine whether these findings can be generalized to broader patient populations.Clinical Trial Registration: https://www.chictr.org.cn/showproj.html?proj=203874, identifier ChiCTR2300075567.