European Journal of Cardiovascular Medicine

Neuraxial blockade remains a cornerstone of regional anesthesia, offering effective intraoperative anesthesia and postoperative analgesia across a wide range of surgical procedures. The success of these techniques critically depends on precise needle placement into the epidural or subarachnoid space. Traditional landmark-based methods rely on surface anatomy and tactile feedback, which may be unreliable in obese or anatomically distorted patients, often resulting in multiple puncture attempts, prolonged procedure time, and higher complication rates [1,2].

Fluoroscopy guidance has long been considered the gold standard for interventional spinal and pain procedures, as it enables real-time visualization of the needle trajectory and confirmation of contrast spread, ensuring accurate placement [3]. However, fluoroscopy involves ionizing radiation exposure to both patients and operators, requires specialized radiological infrastructure, and is not always feasible in standard operating environments [3,4].

Ultrasound (US) guidance has recently emerged as a promising alternative imaging modality, providing dynamic visualization of neuraxial anatomy, identification of the optimal puncture site, and real-time needle tracking—all without radiation exposure [4,5]. The use of ultrasound has been shown to enhance procedural efficiency by reducing the number of attempts and redirections while improving first-pass success, especially in technically challenging cases [2,5].

Despite the expanding role of ultrasound in regional anesthesia, limited evidence directly compares its efficacy and safety profile with fluoroscopy guidance in neuraxial block procedures. Hence, the present study was designed to compare ultrasound-guided versus fluoroscopy-guided neuraxial blocks, focusing on their success rate, technical efficiency, and safety profile in a tertiary-care clinical setting. 

Study Design and Setting

This prospective comparative study was conducted in the Department of Anaesthesiology, Navodaya Medical College and Hospital, Raichur, Karnataka, from November 2024 to April 2025. The study aimed to evaluate and compare the procedural success and safety profile of ultrasound-guided and fluoroscopy-guided neuraxial blocks in patients undergoing elective lower abdominal or lower limb surgeries under regional anesthesia.

Study Population

A total of 50 adult patients aged between 18 and 65 years, belonging to ASA physical status I–III, were enrolled after obtaining written informed consent. Patients were randomly allocated into two equal groups (n = 25 each):

Group U (Ultrasound-guided neuraxial block)

Group F (Fluoroscopy-guided neuraxial block)

Inclusion Criteria

Patients scheduled for elective lower abdominal, pelvic, or lower limb surgery under neuraxial anesthesia.

Age 18–65 years, either sex.

ASA physical status I–III.

Exclusion Criteria

Local infection at the puncture site.

Coagulopathy or anticoagulant therapy.

Known spinal deformity or previous spine surgery.

Patient refusal or inability to cooperate.

Morbid obesity (BMI > 35 kg/m²).

Preoperative Preparation

All patients underwent routine pre-anesthetic evaluation and were fasted as per institutional protocol. Standard monitors (ECG, NIBP, SpO₂) were attached in the operating room. Intravenous access was secured, and baseline parameters were recorded.

Procedure Technique

Patients were positioned in the sitting posture. Under strict aseptic precautions:

In Group U, the lumbar intervertebral space was identified using a high-frequency linear ultrasound probe (6–13 MHz). The optimal puncture site and trajectory were marked using the paramedian sagittal oblique view. A 22G spinal or Tuohy needle was advanced under real-time ultrasound guidance until loss of resistance was achieved, and the block was administered.

In Group F, the procedure was performed under fluoroscopic guidance (C-arm) using anteroposterior and lateral projections to confirm needle placement within the epidural or subarachnoid space. Radiographic confirmation of contrast spread was obtained before injecting the local anesthetic.

The total duration from skin puncture to successful entry into the desired space was recorded as skin-to-space time. The number of needle attempts and redirections were documented.

Outcome Measures

Primary outcomes included:

Overall block success rate (adequate sensory and motor blockade without conversion).

First-pass success rate (successful block on first needle insertion).

Secondary outcomes included:

Number of attempts and redirections.

Skin-to-space time.

Procedure-related complications such as paresthesia, dural puncture, vascular puncture, hypotension, and post-dural puncture headache.

Patient satisfaction (scored on a 0–10 visual analogue scale).

Radiation exposure parameters in the fluoroscopy group (fluoroscopy time and dose–area product).

Statistical Analysis

Data were entered into Microsoft Excel and analyzed using SPSS version 26.0 (IBM Corp., USA). Continuous variables were expressed as mean ± standard deviation (SD) and compared using the Student’s t-test or Mann–Whitney U test as appropriate. Categorical variables were compared using the Chi-square test or Fisher’s exact test. A p-value < 0.05 was considered statistically significant.

Necessary permissions were obtained before commencing the study. All participants provided written informed consent. The study adhered to the principles outlined in the Declaration of Helsinki.

A total of fifty patients were enrolled and equally divided into two groups: ultrasound-guided neuraxial block (n = 25) and fluoroscopy-guided neuraxial block (n = 25). The demographic and baseline parameters were comparable between the two groups, as summarized in Table 1. The mean age, body mass index, and distribution of ASA physical status did not differ significantly. The duration of surgery was also similar across both groups (78.4 ± 22.6 min vs 80.3 ± 24.8 min, p = 0.741), confirming homogeneity of the study population.

Table 1. Demographic and Baseline Characteristics (n = 50)

Procedural performance and efficiency are outlined in Table 2. Both groups achieved high overall block success rates (ultrasound 96% vs fluoroscopy 92%; p = 1.000). However, first-pass success was higher in the ultrasound group (72% vs 44%; p = 0.085). The number of attempts required was significantly fewer with ultrasound (1.4 ± 0.6 vs 2.1 ± 0.8; p = 0.021), and the median number of needle redirections was also lower (1 [IQR 1–2] vs 2 [IQR 1–3]; p = 0.030). The mean skin-to-space time was shorter in the ultrasound group (5.6 ± 1.7 min) than in the fluoroscopy group (6.4 ± 2.0 min), though this difference did not reach statistical significance (p = 0.134).

Table 2. Procedural Success and Technical Efficiency

*Significant at p < 0.05.

Figure1: Procedural Success and Technical Efficiency

The safety outcomes and procedural complications are presented in Table 3. Paresthesia occurred significantly less frequently in the ultrasound group (4%) compared to the fluoroscopy group (28%; p = 0.049). Incidences of accidental dural puncture (0 vs 8%), vascular puncture (0 vs 4%), post-dural puncture headache (0 vs 4%), and hypotension requiring vasopressors (20% vs 24%) were not statistically significant between groups.

Table 3. Safety Outcomes and Complications

*Significant at p < 0.05.

Patient experience and radiation exposure findings are detailed in Table 4. Mean satisfaction scores were significantly higher in the ultrasound-guided group (8.9 ± 0.8) compared with the fluoroscopy-guided group (8.2 ± 1.1; p = 0.014). Procedure-related discomfort was less frequent with ultrasound (8% vs 24%; p = 0.247). Expectedly, radiation exposure was confined to the fluoroscopy group, with a mean fluoroscopy time of 17.8 ± 6.5 seconds and a dose–area product of 0.11 ± 0.05 Gy·cm², whereas no radiation was recorded in the ultrasound group.

Table 4. Patient Experience and Radiation Parameters

*Significant at p < 0.05.

The present prospective comparative study evaluated the efficacy and safety of ultrasound-guided versus fluoroscopy-guided neuraxial blocks in fifty adult patients undergoing elective lower abdominal and lower limb surgeries. Both imaging modalities demonstrated high overall success; however, ultrasound guidance provided superior procedural efficiency, reflected by higher first-pass success, fewer needle manipulations, lower incidence of paresthesia, and greater patient satisfaction, while completely avoiding radiation exposure.

Our findings correspond with previous reports that showed comparable block success between ultrasound and fluoroscopy when procedures are performed by trained operators. Jang et al. (2020) demonstrated similar analgesic outcomes between ultrasound-guided selective nerve root blocks and fluoroscopy-guided epidural injections, emphasizing operator experience as a determining factor of success [6]. Likewise, Güven Köse et al. (2023) observed no compromise in accuracy with ultrasound while achieving significant reduction in procedure time, validating its clinical reliability [7].

The higher first-pass success (72 % vs 44 %) and fewer needle redirections noted in our study reinforce evidence that pre-puncture ultrasound imaging improves estimation of depth and trajectory. Kamimura et al. (2024), in a comprehensive network meta-analysis, confirmed that ultrasound guidance significantly enhances the first-attempt success of neuraxial puncture and minimizes technical difficulty compared with landmark methods [8].

The shorter mean skin-to-space time in the ultrasound group, though not statistically significant, mirrors earlier observations that proficiency improves with experience. Onishi and Yamauchi (2014) highlighted that ultrasound-guided neuraxial blocks evolve rapidly in practice as clinicians overcome the learning curve, resulting in faster and more precise access to the epidural or subarachnoid space [9].

Regarding safety, the markedly lower incidence of paresthesia with ultrasound guidance (4 % vs 28 %) supports the growing consensus that real-time visualization prevents inadvertent neural contact. Park et al. (2013) similarly demonstrated that ultrasound-guided caudal epidural steroid injections significantly reduced pain during needle advancement and procedural discomfort compared with fluoroscopic techniques [10]. Importantly, in our series, no major complications—such as accidental dural puncture or neurological injury—were observed in either group, underscoring the inherent safety of both modalities when performed under imaging control.

Patient satisfaction was significantly higher in the ultrasound group, reflecting less procedural anxiety and discomfort. Viderman et al. (2023), in a meta-analysis of randomized trials, also reported improved patient experience and reduced adverse events with ultrasound compared to fluoroscopy across diverse spinal interventions [11]. Moreover, the absence of ionizing radiation with ultrasound presents a major occupational and patient safety advantage. Fluoroscopy, although invaluable for interventional pain procedures, carries potential radiation hazards and increases procedural complexity. In a recent comparative analysis, Kesikburun et al. (2025) demonstrated that hybrid ultrasound/fluoroscopy techniques markedly reduced fluoroscopy time and radiation dose compared with fluoroscopy alone, further reinforcing the safety value of ultrasound integration [12].

The present study demonstrated that both ultrasound-guided and fluoroscopy-guided neuraxial blocks are effective and safe techniques for regional anesthesia. However, ultrasound guidance provided superior procedural efficiency, reflected by higher first-pass success, fewer needle attempts, reduced paresthesia, and greater patient satisfaction. Importantly, it eliminated radiation exposure, making it a safer and more practical alternative, particularly in routine anesthetic practice. While fluoroscopy offers precise anatomical confirmation, its requirement for specialized equipment and radiation limits its routine applicability. Hence, ultrasound guidance can be recommended as a reliable, radiation-free, and patient-friendly technique for neuraxial blockade, particularly in teaching hospitals and high-volume clinical settings.

1. Evansa I, Logina I, Vanags I, Borgeat A. Ultrasound versus fluoroscopic-guided epidural steroid injections in patients with degenerative spinal diseases: a randomised study. Eur J Anaesthesiol. 2015 Apr;32(4):262-8. doi: 10.1097/EJA.0000000000000103. PMID: 24841502.
2. Goel S, Mitra S, Singh J, Jindal S, Upadhyay P, Jindal R. Comparison of ultrasound and fluoroscopy-guided caudal epidural block in low back pain with radiculopathy: A randomized controlled study. J Anaesthesiol Clin Pharmacol. 2025 Jan-Mar;41(1):106-111. doi: 10.4103/joacp.joacp_388_23. Epub 2024 Aug 16. PMID: 40026732; PMCID: PMC11867380.
3. Viderman D, Aubakirova M, Aryngazin A, Yessimova D, Kaldybayev D, Tankacheyev R, Abdildin YG. Ultrasound-Guided vs. Fluoroscopy-Guided Interventions for Back Pain Management: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Diagnostics (Basel). 2023 Nov 18;13(22):3474. doi: 10.3390/diagnostics13223474. PMID: 37998610; PMCID: PMC10670286.
4. Ahmed M, Ahmad A, Arshad M, Naseer H, Zamarud A. Ultrasound-Guided Versus Conventional Fluoroscopy-Guided Epidural Injection for Radiculopathy. A Meta-Analysis of Randomized Controlled Trials. World Neurosurg. 2023 Dec;180:203-212.e4. doi: 10.1016/j.wneu.2023.09.088. Epub 2023 Sep 27. PMID: 37774791.
5. Hazra AK, Bhattacharya D, Mukherjee S, Ghosh S, Mitra M, Mandal M. Ultrasound versus fluoroscopy-guided caudal epidural steroid injection for the treatment of chronic low back pain with radiculopathy: A randomised, controlled clinical trial. Indian J Anaesth. 2016 Jun;60(6):388-92. doi: 10.4103/0019-5049.183391. PMID: 27330199; PMCID: PMC4910477.
6. Jang JH, Lee WY, Kim JW, Cho KR, Nam SH, Park Y. Ultrasound-Guided Selective Nerve Root Block versus Fluoroscopy-Guided Interlaminar Epidural Block versus Fluoroscopy-Guided Transforaminal Epidural Block for the Treatment of Radicular Pain in the Lower Cervical Spine: A Retrospective Comparative Study. Pain Res Manag. 2020 Jun 13;2020:9103421. doi: 10.1155/2020/9103421. PMID: 32617125; PMCID: PMC7306851.
7. Güven Köse S, Köse HC, Çelikel F, Akkaya ÖT. Fluoroscopy-Guided Versus Fluoroscopy-Confirmed Ultrasound-Guided S1 Transforaminal Epidural Injection with Pulsed Radiofrequency: A Prospective, Randomized Trial. Eurasian J Med. 2023 Feb;55(1):43-49. doi: 10.5152/eurasianjmed.2023.22265. PMID: 36861865; PMCID: PMC10081137.
8. Kamimura Y, Yamamoto N, Shiroshita A, Miura T, Tsuji T, Someko H, Imai E, Kimura R, Sobue K. Comparative efficacy of ultrasound guidance or conventional anatomical landmarks for neuraxial puncture in adult patients: a systematic review and network meta-analysis. Br J Anaesth. 2024 May;132(5):1097-1111. doi: 10.1016/j.bja.2023.09.006. Epub 2023 Oct 6. PMID: 37806932.
9. Onishi E, Yamauchi M. [The trends of ultrasound-guided neuraxial block]. Masui. 2014 Sep;63(9):1011-7. Japanese. PMID: 25255663.
10. Park Y, Lee JH, Park KD, Ahn JK, Park J, Jee H. Ultrasound-guided vs. fluoroscopy-guided caudal epidural steroid injection for the treatment of unilateral lower lumbar radicular pain: a prospective, randomized, single-blind clinical study. Am J Phys Med Rehabil. 2013 Jul;92(7):575-86. doi: 10.1097/PHM.0b013e318292356b. PMID: 23636087.
11. Viderman D, Aubakirova M, Aryngazin A, Yessimova D, Kaldybayev D, Tankacheyev R, Abdildin YG. Ultrasound-Guided vs. Fluoroscopy-Guided Interventions for Back Pain Management: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Diagnostics (Basel). 2023 Nov 18;13(22):3474. doi: 10.3390/diagnostics13223474. PMID: 37998610; PMCID: PMC10670286.
12. Kesikburun S, Artuç ŞE, Çelik Karbancioğlu E, Kesikburun B, Adigüzel E, Yaşar E. The effect of hybrid ultrasound/fluoroscopy guidance vs only fluoroscopy guidance on procedure time and radiation exposure in caudal epidural steroid injections. Interv Pain Med. 2025 Mar 5;4(1):100567. doi: 10.1016/j.inpm.2025.100567. PMID: 40124674; PMCID: PMC11929079.