The Myth of the Equiangular Triangle for Identification of Sacral Hiatus in Children Disproved by Ultrasonography:

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.

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.

A randomized double-blinded controlled trial comparing ultrasound-guided versus conventional injection for caudal block in children undergoing infra-umbilical surgeries

Background and Aims:

Caudal epidural block is widely used in pediatric surgeries to provide intraoperative and postoperative analgesia in infra-umbilical surgeries. The conventional technique involves the risk of multiple punctures and other complications such as dural puncture, vascular puncture, and intraosseous injection.

Material and Methods:

Around 106 children aged between 6 months to 10 years belonging to ASA class I-II scheduled for elective infra-umbilical surgeries were included after obtaining written informed consent from parents/guardians. All children were randomized into two groups: ultrasound-guided (Group U) or conventional caudal group (Group C). All were premedicated with oral midazolam and inhalational induction was done with oxygen and 6–8% sevoflurane. Caudal block of 1 mL/kg of 0.125% bupivacaine was administered in both groups. The primary outcome assessed was 1^st puncture success rate and the secondary outcomes assessed were number of skin punctures, block performing time, and block success rate.

Results:

Group U had a higher first puncture success rate (P = 0.001) than Group C (90.6% v/s 64.2%) and was statistically significant. The number of punctures were significantly less (P = 0.01) in Group U (1.09 ± 0.295) than Group C (1.45 ± 0.667). Block performing time was significantly higher (P = 0.0005) in Group U (53.19 ± 10.97 s) than Group C (30.34 ± 7.34 s). There was no difference in the overall block success rate between the groups (98.1% v/s 100%).

Conclusion:

Ultrasound-guided caudal injection increases the first puncture success rate and decreases the number of punctures required compared to conventional caudal block in pediatric infra-umbilical surgeries.

Intrasacral Meningocele Complicating Caudal Analgesia in a 6-Year-Old Child After 3 Previous Uneventful Caudals: A Case Report

A 6-year-old male undergoing bilateral hydrocelectomy was to receive caudal analgesia after induction of general anesthesia. After insertion of the caudal needle, cerebrospinal fluid was unexpectedly aspirated and the caudal was abandoned. The surgeon performed bilateral ilioinguinal nerve blocks just before incision. Surgery was uneventful. The patient had difficulty ambulating postoperatively, and a detailed neurologic examination revealed quadriceps weakness. A lumbosacral magnetic resonance imaging (MRI) revealed a sacral meningocele. By the next morning, quadriceps function had returned, and he was ambulating normally. The ilioinguinal block was most likely deep to the internal oblique muscle and produced femoral nerve dysfunction.

Ultrasound-guided versus conventional injection for caudal block in children: A prospective randomized clinical study

STUDY OBJECTIVE

The aim of this study was to compare the efficacies of ultrasound guided sacral hiatus injection and conventional sacral canal injection performed for caudal block in children.

DESIGN

Randomized controlled clinical trial.

SETTING

Operating rooms of university hospital of Erzurum, Turkey.

PATIENTS

One hundred-thirty four children, American Society of Anesthesiologists I-II, between the ages of 5 and 12, scheduled for elective phimosis and circumcision surgery.

INTERVENTIONS

Patients assigned to two groups for ultrasound guided caudal block (Group U, n=68) or conventional caudal block (Group C, n=66). Caudal solution was prepared as 0.125% levobupivacaine plus 10mcg/kg morphine (total volume: 0.5ml/kg), and was administered to both groups.

MEASUREMENTS

The block performing time, the block success rate, the number of needle puncture, the success at first puncture and the complications were recorded.

MAIN RESULTS

The block performing time and the success rate of block were similar between Group U and Group C (109.96±49.73s vs 103.17±45.12s, and 97% vs 93%, respectively p>0.05). The first puncture success rate was higher in Group U than in Group C (80% vs 63%, respectively p=0.026). No significant difference was observed between the groups with regard to the number of needle punctures (p=0.060). The rates of vascular puncture and subcutaneus bulging were higher in Group C than in Group U (8/66 vs 1/68, and 8/66 vs 0/68, respectively p<0.05).

CONCLUSIONS

Despite the limitations in central neuroaxial anesthesia we recommend the use of ultrasound since it reduces the complications and increases the success rate of first puncture in pediatric caudal injection.

Rectal puncture complicating caudal blockade in a child with severe rectal distension

We describe a case of unrecognized rectal puncture following unsuccessful caudal blockade in a patient later found to have marked rectal distension on MRI. This may have contributed to the rectal injury.

Should we abandon landmark-based technique for caudal anesthesia in neonates and infants?

BACKGROUND

Caudal anesthesia is a landmark-based technique with ultrasound guidance occasionally used in the absence of landmarks. The current surface landmark remains a popular approach due to its desirable success rate. However, incomplete ossification of the posterior vertebral elements can make this procedure for neonatal caudal anesthesia difficult. The aim of this study was to describe the anatomical relationship of the posterior superior iliac spines (PSISs) to the sacral cornua in infants using ultrasound.

METHODS

A total of 26 healthy infants (17 female; mean age 13 weeks) were scanned by an experienced radiologist in the prone position with hip and knee joints flexed. The PSISs and sacral cornua were identified clinically then using ultrasound to assess whether these markings corresponded with the clinical markings. The distance between the PSISs and the distance between the tip of the PSIS and tip of the sacral cornu were measured using ultrasound.

RESULTS

The PSISs were clinically identified in all babies, but the sacral cornua were not palpable in four babies (15%). The PSISs and sacral cornua were easily visualized using ultrasound in all participants. The mean distance between the two left and right PSISs was 3.4 ± 0.5 cm; the mean distance between the PSISs and cornu was 2.5 ± 0.5 cm on the left and right.

CONCLUSION

This study showed that the current landmark (equilateral triangle) for infant caudal anesthesia is unreliable. Importantly, the sacral hiatus is clinically identifiable only if the sacral cornua are palpable; otherwise, using ultrasound is essential.

A review of the surface and internal anatomy of the caudal canal in children

The anatomy of the sacral hiatus and caudal canal is prone to significant variation, yet studies assessing this in the pediatric population remain limited. Awareness of the possible anatomical variations is critical to the safety and success of caudal epidural blocks, particularly when image guidance is not employed. This systematic review analyzes the available evidence on the clinical anatomy of the caudal canal in pediatric patients, emphasizing surface anatomy and internal anatomical variations. A literature search using three electronic databases and standard pediatric and anatomy reference texts was conducted yielding 24 primary and seven secondary English-language sources. Appreciating that our current landmark-guided approaches to the caudal canal are not well studied in the pediatric population is important for both clinicians and researchers.