Ultrasound versus anatomical landmarks for caudal epidural anesthesia in pediatric patients

Evaluation of sacral hiatus changes in children using ultrasound

Background and objectives

The intercornual distance in the sacral hiatus has yet to be studied precisely in children. This age-stratified, observational study aimed to clarify the changes in sacral hiatus dimensions and to quantify the correlations between the intercornual distance of the sacral hiatus and age, height, weight, and head circumference by using real-time ultrasonography.

Methods

The patients were stratified into three groups: neonates and infants, toddlers, and schoolchildren. In the operating room, the ultrasonic probe was placed at the sacral cornua to obtain a transverse view of the sacral hiatus, and the intercornual distance was measured three times in millimetres.

Results

The study included a total of 156 patients. The mean ± SD (95%CI) of intercornual distance in neonates and infants (<12 months) was 11.58 ± 1.79 (11.11-12.04) mm, 13.29 ± 1.97 (12.71-13.86) mm in toddlers (13-36 months), and 13.36 ± 2.49 (12.64-14.08) mm in schoolchildren (>36 months).The mean values of neonates and infants were different from those of toddlers and schoolchildren (p < 0.001), but it was similar between toddlers and schoolchildren (p > 0.05, 95 % CI mean difference -1.10 to 0.95).Intercornual distance was correlated with age, height, weight, and head circumference before one year of age (Spearman's R values > 0.7), but there was no correlation thereafter (Spearman's p value > 0.05).

Conclusion

In the first year after birth, the intercornual distance increases rapidly with body growth; after one year of age, the sacral hiatus dimension changes significantly. Ultrasound is superior for assessing the gradually ossified cartilage components in older children.

Ultrasound-guided caudal anaesthesia combined with epidural anaesthesia for caesarean section: a randomized controlled clinical trial

BACKGROUND

Although epidural anaesthesia and spinal anaesthesia are currently the general choices for patients undergoing caesarean section, these two neuraxial anaesthesia methods still have drawbacks. Caudal anaesthesia has been considered to be more appropriate for gynaecological surgery. The purpose of this study was to compare epidural anaesthesia combined with caudal anaesthesia, spinal anaesthesia and single-space epidural anaesthesia for caesarean section with respect to postoperative comfort and intraoperative anaesthesia quality.

METHODS

In this clinical trial, 150 patients undergoing elective caesarean section were recruited and randomized into three groups according to a ratio of 1:1:1to receive epidural anaesthesia only, spinal anaesthesia only or epidural anaesthesia combined with caudal anaesthesia. The primary outcome was postoperative comfort in the three groups. Secondary outcomes included intraoperative anaesthesia quality and the incidences of nausea, vomiting, postdural puncture headache, maternal bradycardia, or hypotension.

RESULTS

More patients were satisfied with the intraoperative anaesthesia quality in the EAC group than in the EA group (P = 0.001). The obstetrician was more significantly satisfied with the intraoperative anaesthesia quality in the SA and EAC groups than in the EA group (P = 0.004 and 0.020, respectively). The parturients felt more comfortable after surgery in the EA and EAC groups (P = 0.007). The incidence of maternal hypotension during caesarean section was higher in the SA group than in the EA and EAC groups (P = 0.001 and 0.019, respectively).

CONCLUSIONS

Epidural anaesthesia combined with caudal anaesthesia may be a better choice for elective caesarean section. Compared with epidural anaesthesia and spinal anaesthesia, it has a higher quality of postoperative comfort and intraoperative anaesthesia.

Establishment of Difficult Caudal Epidural Blockade Prediction Model

Background

We aimed to develop a predictive difficult caudal epidural blockade (pDCEB) model when ultrasound was not available and verified the role of ultrasound in difficult caudal epidural blockade (CEB).

Methods

From October 2018 to March 2019, this study consisted of three phases. First, we prospectively enrolled 202 patients scheduled to undergo caudal epidural anesthesia and assessed risk factors by binary logistic regression to develop the predictive scoring system. Second, we enrolled 87 patients to validate it. The receiver operating characteristic (ROC) curve was used to evaluate the performance of the prediction model. Youden-index was used to determine the cut-off value. 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 between unclear palpation of the sacral hiatus (OR 9.688) and cornua (OR 4.725), the number of the sacral hiatus by palpation ≥1 (OR 4.451), and history of difficult CEB (OR 39.282) with a 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, a preprocedure ultrasound scan could reduce the incidence of difficult CEB (55.56% in the Landmark group vs. 9.38% in the ultrasound group, p < 0.001).

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. Trial registration: No: ChiCTR1800018871, Site URL: https://www.chictr.org.cn/edit.aspx?pid=31875&htm=4; Principal investigator: Jialian Zhao, Date of registration: 2018.10.14.

Comparative evaluation of landmark technique and ultrasound-guided caudal epidural injection in pediatric population: A systematic review and meta-analysis

BACKGROUND

Caudal block is a common regional anesthesia technique in pediatrics with landmark method predominantly being practiced. Ultrasound-guided technique provides real-time visualization of the structures and injection while performing caudal block. We performed this meta-analysis to determine the utility of ultrasound in caudal blocks in children over the landmark-based technique.

METHODS

Randomized controlled trials comparing ultrasound-guided caudal blocks and landmark technique in pediatrics were searched from databases-PubMed, Embase, Scopus, and CENTRAL from inception until August 2020. The primary objective was success rate between the two techniques and secondary objectives included time to perform the block, first puncture success, and complications.

RESULTS

Five trials with 904 participants were included for this meta-analysis. There was no difference in success rate between the two techniques (Risk ratio-1.07; 95% CI [0.97, 1.18]; p = .15). Time to perform the block was similar (Mean difference-8.88 s; 95% CI [-21.64, 39.40; p = .57) while first puncture success was higher with ultrasound-guided technique (Risk ratio-1.31; 95% CI [1.15, 1.49]; p = .0001). Complications like vascular puncture and needle misplacement were lower in the ultrasound group, and no serious complications were seen in any patient. Needle visualization and sacral canal distension were seen in 82% and 97.5% of the cases, respectively, in ultrasound group.

CONCLUSION

Ultrasound-guided caudal injection does not improve the success rate or time to perform the block but results in higher first puncture success and lower incidence of complications compared to landmark technique.

Comparison of Landmark-guided, Nerve Stimulation-guided, and Ultrasound-guided Techniques for Pediatric Caudal Epidural Anesthesia: A Prospective Randomized Controlled Trial

OBJECTIVES

Traditionally, caudal epidurals are performed by a landmark-guided approach using the loss of resistance technique. Improvisations to increase the success rate can be attained by implementing modalities, namely neurostimulation and ultrasound, but there is a paucity of literature comparing these 3 approaches. Here, we compare the 3 techniques in terms of the success rate.

MATERIALS AND METHODS

The primary outcome of this study was to compare the success rate of the 3 techniques, and the secondary outcome was the blood or cerebrospinal fluid aspiration during the procedure. It was a prospective, randomized, open-label parallel-group study. Three hundred children aged 1 to 5 years scheduled for circumcision, hypospadias repair, and minor lower extremity surgeries were enrolled after taking written informed consent from the parents.

RESULTS

Demographic profiles were comparable in terms of age, weight, sex distribution, and types of surgeries. Success rates in landmark-guided, neurostimulation-guided, and ultrasound-guided were 97%, 97%, and 98%, respectively which was comparable (P=0.879). There was no significant difference in the incidence of blood or cerebrospinal fluid aspiration.

DISCUSSION

We found a similar success rate of the caudal epidural block by using landmark-guided, nerve stimulation-guided, or ultrasound-guided techniques in children aged 1 to 5 years with normal anatomy.

The minimum effective concentration (MEC90) of ropivacaine for ultrasound-guided caudal block in anorectal surgery. A dose finding study

Background

Caudal epidural block (CEB) provides reliable anesthesia for adults undergoing anorectal surgery. Despite the widely utilization, the minimum effective concentration for 90% patients (MEC₉₀) of ropivacaine for CEB remains unknown.

Objective

To estimate MEC of ropivacaine for CEB in anorectal surgery.

Design

A prospective dose-finding study using biased coin design up-and-down sequential method.

Setting

Operating room and postoperative recovery area of Chengdu Shangjin Nanfu Hospital, from October 2019 to January 2020.

Patients

50 males and 51 females scheduled for anorectal surgery.

Interventions

We conducted two independent biased coin design up-and down trials by genders. The concentration of ropivacaine administered to the first patient of male and female were 0.25% with fixed volume of 14ml for male and 12ml for female patients based on our previous study. In case of failure, the concentration was increased by 0.05% in the next subject. Otherwise, the next subject was randomized to a concentration 0.05% less with a probability of 0.11, or the same concentration with a probability of 0.89. Success was defined as complete sensory blockade of perineal area 15 min after the block evidenced by the presence of a lax anal sphincter and pain-free surgery.

Main outcome measures

The MEC of ropivacaine to achieve a successful CEB in 90%(MEC₉₀) of the patients.

Results

The MEC₉₀ of ropivacaine for CEB were estimated to be 0.35% (95% CI 0.29 to 0.4%) for male and 0.353% (95%CI 0.22 to 0.4%) for female. By extrapolation to MEC in 99% of subjects (MEC99) and pooled adjacent violators algorithm (PAVA) adjusted responses, it would be optimal to choose 0.4% ropivacaine with a volume of 14ml for male and 12ml for female.

Conclusions

A concentration of 0.35% ropivacaine with a volume of 14ml provided a successful CEB in 90% of the male patients, while 0.353% ropivacaine with a volume of 12ml provided a successful CEB in 90% of the female patients. A concentration of 0.4% and a volume of 14ml for male and 12 ml for female would be successful in 99% of the patients.

Trial registration

Chictr.org.cn identifier: No. ChiCTR 1900024315.

Ultrasound in paediatric anaesthesia - A comprehensive review

The use of ultrasound is becoming more widespread in anaesthesia. In this review, we discuss the use of ultrasound in various aspects of paediatric anaesthesia and how it can be used to assist diagnostic and therapeutic interventions and the evidence available. We explore the use of ultrasound as an adjunct for regional anaesthesia, vascular access, airway management, bedside cardiac, pulmonary and abdominal imaging and intracranial pressure monitoring.

Concordance between the loss of resistance technique and ultrasound in measuring the distance from the skin to the epidural space in pediatric patients: Observational study

Introduction: The use of ultrasound in regional anesthesia has become a standard technique to improve nerve block accuracy and reduce associated complications. The literature reports a good correlation between the distance from the skin to the dura mater or the ligamentum flavum measured on ultrasound and the conventional technique of “loss of resistance”. Latin American populations have not been included in the studies conducted so far but, because of differences in physical build, it is important to determine whether this correlation is maintained in the various populations. This paper offers new information about the role of ultrasound in determining the distance to the ligamentum flavum and recognizing the proximity of the dura mater to avoid accidental puncture of this structure in Latin American populations. Objective: To determine correlation and concordance in estimating the distance from the skin to the epidural space between the loss of resistance technique and ultrasound measurement. Methodology: Observational study conducted in 52 pediatric patients who received general anesthesia plus peridural analgesia for acute perioperative pain management between July 2014 and November 2015 to assess correlation and concordance between loss of resistance and ultrasound measurement of distance to the epidural space. Results: There is a correlation between distances measured using the two techniques, which appears to be higher as patient age increases. As for concordance, the study found that 0.43 cm should be added to the ultrasound measurement to achieve agreement with the distance obtained using the loss of resistance technique; however, the interval between the two measurements is 1.15 cm. Conclusions: A correlation was found between the measurement taken from the skin to the peridural space using ultrasound and the measurement obtained with the traditional needle puncture and loss of resistance technique. Although concordance was not as expected and the distance measured with ultrasound may be smaller than the real measurement with the needle, ultrasound offers good guidance regarding proximity to the peridural space.

Confirmation of success rate of landmark-based caudal blockade in children using ultrasound: A prospective analysis

BACKGROUND

Caudal epidural anesthesia is a frequently performed regional anesthesia block in infants and young children. Traditional landmark-based blind needle insertion remains the norm with no immediate, objective method to determine the presence of local anesthetic in the epidural space. Increasingly, ultrasound-imaging is used in pediatric regional anesthesia with demonstrated improvements in block efficacy and efficiency. The value of ultrasound-imaging in confirming success rate of traditional caudal placement is not well defined.

AIM

To assess the success rate of conventional landmark-based caudal technique using ultrasound-imaging.

METHODS

Prospective observational study of 30 children ages 1 month to 7 years undergoing surgical procedures with consent for caudal blockade. Provider success rate of caudal blockade placed by landmark technique was measured using ultrasound-imaging of needle tip and local anesthetic flow in the epidural space.

RESULTS

Ultrasound-imaging demonstrated 80% success to correct positioning of the needle tip and local anesthetic in the epidural space. Failure was associated with decreasing experience and presence of anatomic variances. All improperly positioned needles were subsequently successfully positioned using real-time ultrasound-imaging. Mean time for confirmatory ultrasound-imaging (SD; range) was 1 minute (0.3; 1-3).

CONCLUSION

The use of ultrasound-imaging can be used to identify proper needle placement in the sacral epidural canal and facilitate subsequent corrected placement.

Ultrasound guidance for difficult lumbar puncture in children: pearls and pitfalls

Pediatric lumbar puncture can be challenging or unsuccessful for several reasons. At the same time, the excellent sonographic window into the pediatric spine provides a distinct opportunity for ultrasound-guided lumbar puncture. Minimal cerebrospinal fluid and thecal displacement by subdural or epidural hematomas are common after failed clinical attempts. Ultrasound is useful for determining a safe infraconal level for subarachnoid access. Real-time guidance increases not only the success rate but also the safety of diagnostic lumbar puncture and injections for chemotherapy and myelography. In this article, we discuss clinical and technical factors for ultrasound-guided pediatric lumbar puncture.

Anatomy of the sacral hiatus and its clinical relevance in caudal epidural block

PURPOSE

Caudal epidural anesthesia (CEB) is widely used for the prevention of chronic lower back pain, the control of intraoperative analgesia such as genitourinary surgery and labor pain cases in sacral epidural space approach for the implementation of analgesia. CEB is an anesthetic solution used into the sacral canal via sacral hiatus (SH). For optimal access into the sacral epidural space, detailed anatomical landmarks of SH are required. This study aims at exploring the anatomical structures and differences of the SH by using the sacral bone as a guide point to failure criteria for reviewing the caudal epidural anesthesia and improving the criteria for success in practice.

MATERIALS AND METHODS

Detailed morphometric measurements of orientation points of the SH were taken in 87 sacral bones. The measurements were taken using digital calipers and calculated with photogrammetric methods using Image J program.

RESULTS

Most commonly encountered shape of the SH was inverted U (33.33%), while 6.9% 3.45% often lack SH and bifida shape were found. The average length of the SH was 28.7 ± 7.1 mm, the average distance of the intercornual distance was 13.48 ± 2.69 mm, the average of the apex of SH and S2 sacral foramen was 34.68 ± 7.09 mm. There was no statistically significant difference determined in bilateral measurements (p > 0.05). Apex and base of SH were most commonly observed against S4 and S5 vertebrae, respectively. The level of maximum curvature of sacrum was S3 in 62.07% and S4 in 28.78%. Findings of spina bifida level were found 16.13% often in L5-S1 segment. Sacral cornua were marked by their bilateral presence in 55.26% and impalpable in 21.05% cases. Minimum distance between the S2 and the apex of the SH was 7.25 mm which suggested that it would not be safe to push the needle beyond 7 mm into the sacral canal so as to avoid dural puncture. In 8.77% cases, the depth of hiatus was less than 3 mm.

CONCLUSIONS

Single bony landmark may not help in locating the SH because of the anatomical variations. Important anatomical landmarks of the CEB are the sacral cornu, lateral sacral crests, the apex of the SH, the base of the SH, the top portion of the median sacral crest, anteroposterior distance of the sacral canal, intercornual distance, distance of the apex of the SH to the S2 foramina. Depth of hiatus less than 3 mm may be one of the causes for the failure of needle insertion. Surrounding bony irregularities, different shapes of hiatus and defects in dorsal wall of sacral canal should be taken into consideration before undertaking CEB so as to avoid its failure. This guide can be done by considering the points and securing a successful venture.