Anatomic Differences in the Sacral Hiatus During Caudal Epidural Injection Using Ultrasound Guidance

Sex differences in pediatric caudal epidural anesthesia under sedation without primary airway instrumentation

STUDY OBJECTIVE

To identify sex differences associated with caudal epidurals, the most commonly used technique of pediatric regional anesthesia, based on individually validated data of ultrasound-guided blocks performed between 04/2014 and 12/2020.

METHODS

Prospectively collected and individually validated data of a cohort of children aged between 0-15 years was analyzed in a retrospective observational study. We included pediatric surgeries involving a primary plan of caudal epidural anesthesia under sedation (without airway instrumentation) and a contingency plan of general anesthesia. Sex-specific rates were analyzed for overall failure of the primary anesthesia plan, for residual pain, for block-related technical complications and for critical respiratory events. We used Fisher´s exact tests and multivariable logistic regressions were used to evaluate sex-specific associations.

RESULTS

Data from 487 girls and 2060 boys ≤15 years old (ASA status 1 to 4) were analyzed. The primary-anesthesia-plan failure rate was 5.5% (95%CI 3.8%-7.8%) (N = 27/487) among girls and 4.7% (95%CI 3.9%-5.7%) (N = 97/2060) among boys (p = 0.41). Residual pain was the main cause of failure, with rates of 4.5% (95%CI 2.9-6.6%) (N = 22/487) among girls and 3.0% (95%CI 2.3-3.8%) (N = 61/2060) among boys (p = 0.089). Block-related technical complications were seen at rates of 0.8% (95%CI 0.3%-1.9%) (N = 4/487) among girls vs 2.5% (95%CI 0.5-2.7%) (N = 51/2060) among boys and, hence, significantly more often among male patients (p = 0.023). Male sex was significantly associated with higher odds (adjusted OR: 3.18; 95% CI: 1.12-9; p = 0.029) for such technical complications regardless of age, ASA status, gestational week at birth or puncture attempts. Critical respiratory events occurred at a 1.7% (95%CI 1.2%-2.3%) rate (N = 35/2060) twice as high among boys as 0.8% (95%CI 0.3%-1.9%) (N = 4/487) among girls (p = 0.21).

CONCLUSIONS

While the the primary-anesthesia-plan failure rate was equal for girls and boys, technical complications and respiratory events are more likely to occur in boys.

Study on MEV90 of 0.5% ropivacaine for US-guided caudal epidural block in anorectal surgery

Background

Choosing the appropriate concentration and volume of anesthetics is critical for a successful nerve block. The current study aimed to determine the minimum effective volume (MEV) of 0.5% ropivacaine for US-guided CEB in 90% of patients (MEV90) undergoing anorectal surgery. The aims were to reduce the occurrence of complications associated with a sacral blockade in anorectal surgery, broaden the indications for surgical procedures and treatment, and improve patient satisfaction. This study presents the groundwork for the development of individualized anesthetic programs. We believe that the study would serve as a reference for the use of caudal epidural block (CEB) in lower abdominal surgery for intraoperative and postoperative analgesia.

Methods

This study used a biased coin design (BCD) up-and-down method (UDM). We divided the participants into two groups based on gender, and each group independently performed the biased coin design up-and-down method. We used 0.5% ropivacaine for the first patient in each group; however, the volume was 10 ml for men and 8 ml for women. Therefore, the dose of anesthetics given to each patient was determined by the response of the previous patient. If the block of the previous patient failed, the volume was increased by 2 ml in the following patient. Otherwise, the next subject had an 11% chance of receiving a volume of 2 ml less or an 89% chance of receiving no volume change. We defined a successful block as painless surgery with anal sphincter relaxation 15 min after the drug injection. Enrollment was completed after 45 successful caudal blocks for each group.

Results

Caudal epidural block was successfully performed on 50 men and 49 women. The MEV90 of ropivacaine for CEB was calculated to be 12.88 ml (95% CI: 10.8-14 ml) for men and 10.73 ml (95% CI: 9.67-12 ml) for women. Men had a MEV99 of 13.88 ml (95% CI: 12.97-14 ml), and women had a MEV99 of 11.87 ml (95% CI: 11.72-12 ml).

Conclusion

With operability and general applicability, it is possible to increase the success rate of CEB for anorectal surgery to 99% as well as decrease the incidence of anesthesia-related complications. CEB can meet the needs of patients for rapid postoperative rehabilitation, improve patient satisfaction, and lay a solid foundation for postoperative analgesia.

The Effect of Caudal Anesthesia Block on Perioperative Pain Control and Reduction of the Anesthetic Agent in Pediatric Infraumbilical Surgery: A Prospective Randomized Trial Study

Background

Caudal epidural block (CEB) is a commonly performed neuraxial block to provide effective pain relief and analgesia in pediatric patients undergoing infraumbilical surgery.

Aims

This study aimed to compare the effectiveness of adding CEB to general anesthesia (GA) in terms of intra- and postoperative pain management.

Design

Prospective, randomized case-controlled trial study.

Setting

Operation theater, and postoperative recovery rooms at Salmaniya Medical Complex, Bahrain.

Materials and Methods

A total of 74 patients aged 2 months to 6 years with American Society of Anesthesiologists physical status classification I were recruited over a 6-month period between December 2019 and May 2020. Patients were allocated into two groups (Group A, with CEB) or (Group B, without CEB). Both groups were compared based on hemodynamic stability, pain scores, level of sedation, analgesia need, and parental satisfaction.

Statistical Analysis

Data were analyzed using SPSS program. Categorical and numerical variables of both the groups were compared.

Results

Patients with CEB had better hemodynamic stability during the surgical procedure based on heart rate (P = 0.039). Pain intensity scores were less in patients with CEB than those without (P < 0.001). Fentanyl consumption was lower in Group A compared to Group B at the end of surgery (P = 0.002). They were also ambulated earlier and discharged sooner than those without CEB. Parental satisfaction was 92.1% in Group A compared to 63.9% in Group B (P = 0.012).

Conclusions

Adding CEB to GA for intraoperative and perioperative pain control in pediatric patients undergoing infraumbilical surgery makes it more effective, safe, and with better parental satisfaction.

Caudal epidural steroid injection ultrasound-guided versus fluoroscopy-guided in treatment of refractory lumbar disc prolapse with radiculopathy

Background

Lumbar disc prolapse is a localized herniation of disc beyond intervertebral disc space and is the most common cause of sciatica; the aim of this study is to investigate the efficacy of ultrasound (US)-guided caudal epidural steroid injection (CESI) compared with fluoroscopy (FL)-guided CESI in treatment of patients with refractory lumbar disc prolapse (LDP) with radiculopathy.

Results

At the beginning of the study, there was no significant difference between both groups in all parameters. (a) Group 1 had significantly improved the straight leg raising and modified Schober tests, VAS, and ODI at 1-month and 3-month post-injection evaluation in comparison to baseline recordings (p< 0.001); (b) Group 2 had significantly improved the straight leg raising and modified Schober tests, VAS, and ODI at 1-month and 3-month post-injection evaluation in comparison to baseline recordings (p< 0.001); and (c) US-guided CESI was not statistically different from the FL-guided CESI in the improvement of the straight leg raising (p= 0.87, 0.82) and modified Schober tests (p= 0.87, 0.82) as well as VAS (p= 0.40, 0.43) and ODI (p= 0.7, 0.2) at 1-month and 3-month post-injection evaluation. In a multivariate analysis using CI = 95%, the significant predictors for a successful outcome were duration<6 months (p= 0.03, OR = 2.25), target level not L2-3/L3-4 (p< 0.001, OR = 4.13), and LDP other than foraminal type (p= 0.002, OR = 3.78). However, age < 40 years was found to be non-significant in predicting a successful outcome (p= 0.38, OR = 0.98).

Conclusion

US is excellent in guiding CESI with similar treatment outcomes as compared with FL-guided CESI.

Trial registration

ClinicalTrials.gov Identifier:NCT03933150.

Imaging anatomy of the vertebral canal for trans-sacral hiatus puncture of the lumbar cistern

A standard lumbar puncture may be impossible for many anatomic or technical reasons. Previous accounts of caudal epidural anesthesia and other procedures via the sacral hiatus prompted us to test if image-guided percutaneous trans-sacral hiatus access to the lumbosacral subarachnoid cistern would be anatomically feasible. To study vertebral canal morphometry and curvature, we analyzed midsagittal computed tomography-myelogram images of 40 normal subjects and digitally measured sacral curvatures between S1 to S5 and S2 to S4 using two methods whereby a lower angle signifies a straighter sacrum. We measured midsagittal vertebral canal area, hiatus width, dural sac termination levels, and distance from sacral hiatus to the dural sac tip (needle distance). Subjects were F:M = 25:15, with a mean age of 44.9 years. The two S1-S5 full sacral curvature mean angles were 57.3° and 60.4°. Almost all sacral hiatuses were at S4, and dural sac terminations were at S1-S2. The mean S2-S4 sacral curvature was 25.1°, and the mean needle distance was 57.7 mm. Using two-way analysis of variance, there were significant sex differences for needle distances (p = .001), and full and limited sacral curvatures (p = .02, and p = .046, respectively). There were no significant linear regression correlations between age and sacral curvature, needle distance, canal area, or hiatus width. Therefore, despite a frequently prominent full sacral curvature, the combination of S1-S2 dural sac termination plus a relatively straight trajectory of the lower vertebral canal between S2 and S4 support the theoretical feasibility of percutaneous trans-sacral hiatus and vertebral canal access to the lumbosacral cistern using a standard spinal needle.

Caudal Epidural Block: An Updated Review of Anatomy and Techniques

Caudal epidural block is a commonly used technique for surgical anesthesia in children and chronic pain management in adults. It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space. Using conventional blind technique, the failure rate of caudal epidural block in adults is high even in experienced hands. This high failure rate could be attributed to anatomic variations that make locating sacral hiatus difficult. With the advent of fluoroscopy and ultrasound in guiding needle placement, the success rate of caudal epidural block has been markedly improved. Although fluoroscopy is still considered the gold standard when performing caudal epidural injection, ultrasonography has been demonstrated to be highly effective in accurately guiding the needle entering the caudal epidural space and produce comparative treatment outcome as fluoroscopy. Except intravascular and intrathecal injection, ultrasonography could be as effective as fluoroscopy in preventing complications during caudal epidural injection. The relevant anatomy and techniques in performing the caudal epidural block will be briefly reviewed in this article.