Development and Validation of a Predictive Score and Application of Ultrasound for Difficult Caudal Epidural Blockade in Adult Patients：A Prospective Study

Background: We aimed to develop a predictive difficult caudal epidural blockade (pDCEB) model when ultrasound was not available and verify the role of ultrasound in difficult caudal epidural blockade(CEB).Methods: This study consisted of three phases. First, we prospectively enrolled 202 patients and assessed risk factors to develop the predictive scoring system. Second, we enrolled 87 patients to validate it. Third, we enrolled 68 patients with a high risk of difficult CEB (pDCEB score ≥ 3) and randomized them into ultrasound and landmark groups to verify the role of ultrasound. Result: The rate of difficult CEB was 14.98% overall 289 patients. We found a correlation of unclear palpation of the sacral hiatus (OR 9.688) and cornua (OR 4.725), number of the sacral hiatus by palpation ≥ 1 (OR 4.451), and history of difficult CEB (OR 39.282) with higher possibility of difficult CEB. The area under the receiver operating characteristic curve of the pDCEB model involving the aforementioned factors was 0.889 (95% CI, 0.827-0.952) in the development cohort and 0.862 (95% CI, 0.747-0.977) in the validation cohort. For patients with a pDCEB score ≥ 3, pre-procedure ultrasound scan could reduce the incidence of difficult CEB. Conclusion: This novel pDCEB score, which takes into account palpation of the sacral hiatus/cornua, number of the sacral hiatus by palpation ≥ 1, and history of difficult CEB, showed a good predictive ability of difficult CEB. The findings suggested that performing an ultrasound scan is essential for patients with a pDCEB score ≥ 3. 4 Trial registration: No: ChiCTR1800018871, Site url: https://www.chictr.org.cn/edit.aspx?pid=31875&htm=4

Incidence and Factors that Affect Anterior Sacral Foramen Leakage in Fluoroscopically Guided Caudal Epidural Steroid Injection

Background: During the caudal epidural steroid injection (CESI), sacral foramen leakage can occur. The aim of this study was to evaluate incidence and the correlation of anterior sacral foramen leakage with several factors. Methods: We retrospectively analyzed the medical records of patients who underwent CESI. The epidural needle position and sacral foramen leakage (yes or no) in C-arm view were recorded. The following parameters were measured: 1) depth of the intervertebral disc at S1-S2, S2-S3, and S3-S4; 2) distances between the posterior borders of S1 and the apex of the sacral hiatus; and 3) depths of S1, S2 the sacral canal. Results: Ninety-one subjects were evaluated. The patients were predominately women (60%) with a mean age of 65.5 ± 11.6 years. There was leakage in 58% (53/91) of patients. One-level leakage occurred in the largest proportion of patients (27%). Age, gender, needle tip position, the depth of the intervertebral disc at S1-S2, S2-S3, and S3-S4, the distances between the posterior borders of S1 and the apex of the sacral hiatus, and the depths of S1, S2 the sacral canal were not correlated with sacral foramen leakage. Conclusion: We found leakage in 58% of patients regardless of age, gender, needle-tip position, the depth of the intervertebral disc at S1-S2, S2-S3, and S3- S4, the distances between the posterior borders of S1 and the apex of the sacral hiatus, and the depths of S1, S2 the sacral canal. Therefore, clinicians should be aware that leakage can occur in any circumstance. Keywords: incidence, factors, anterior, sacral, foramen, leakage, fluoroscopically, caudal, epidural, steroid, injection.

The Influence of Ultrasound-Guided Technique Using a Catheter-Over-Needle on the Incidence of Accidental Intravascular Injection during Caudal Block-A Retrospective Case Series Study

Background and Objectives: This study was conducted to investigate the influence of an ultrasound-guided technique using a catheter-over-needle when an intravascular injection occurs in patients undergoing a caudal block. Material and Methods: We retrospectively investigated 41 cases of an ultrasound-guided technique using an angiocatheter for caudal block. These had been performed between November 2019 through August 2020 to manage pain of lumbosacral origin. Under ultrasound guidance, after advancing the introducer needle through the sacrococcygeal ligament and then slowly withdrawing it, the outer catheter was continuously advanced into the sacral hiatus. We confirmed proper needle placement under fluoroscopic imaging, using 5 mL of contrast media. We assessed the contrast spread pattern with fluoroscopic imaging and checked it for the presence of intravascular injection. Results: In all recruited cases, the catheter-over-needle was guided successfully to the sacral hiatus and into the caudal epidural space. There was 100% accuracy under ultrasound guidance, without intravascular uptake, as confirmed by contrast media fluoroscopy. The incidence of ventral spread was 84.2% above the S1 with 5 mL of contrast. Conclusions: The technique of using a catheter-over-needle under ultrasound induced successful block without intravascular injection. Thus, this technique is a reliable option for conventional caudal block.

Morphometric Measurement of Sacral Hiatus in Dry Human Sacrum

Introduction: Sacral hiatus is the chief location for caudal epidural anesthesia during surgery of perineal region and also for a pain free parturition. Thus, this study was conducted to examine, measure and record the morphometry of sacral hiatus and to analyze it for any anatomical variations with clinical implications. Methods: The cross-sectional study was carried in the Department of Anatomy, Sikkim Manipal Institute of Medical Science, Gangtok, Sikkim. For the study seventy dry human sacral bone with entire sacral hiatus were measured. The shape of the sacral hiatus was observed. Level of the apex, base, length, width and anterior posterior diameter of sacral hiatus was measured with Digital Vernier Caliper. The study was approved by Institutional Ethical Committee (IEC No:SMIMS/IEC/2017-01). Data were analysed by one-way analysis of variance (ANOVA) and the difference was considered significant when P<0.05. SPSS 20 was used for data analysis. Results: The study revealed inverted “U” shaped sacral hiatus as the common shape in 35(50%) followed by inverted “V” shaped sacra in 18 (25.71 %) followed by irregular shaped sacral hiatus in 8 (11.42 %) cases. A Dumbbell shaped sacral hiatus was observed in 4 (5.71%) cases with a bony protuberance protruding medially from both edges. Absence or complete agenesis of sacral hiatus, a rare phenomenon, was observed in 3 (4.28%) and bifid in 2(2.85%) specimens only. Conclusion: The prevalence of inverted “U” shaped sacral hiatus and constriction of the sacral canal at apex of sacral hiatus was found high. This knowledge of variation in shape of sacral hiatus could be clinically important while providing caudal anesthesia and doing epidural block.