Sacral intervertebral approach for epidural anaesthesia in infants and children: application of "drip and tube" method

Caudal and epidural blocks in infants and small children: historical perspective and ultrasound-guided approaches

In infants and small children, ultrasound (US) guidance provides ample anatomical information to perform neuraxial blocks. We can measure the distance from the skin to the epidural space in the US image and can refer to it during needle insertion. We may also visualize the needle or a catheter during real-time US-guided epidural catheterization. In cases where direct needle or catheter visualization is difficult, US allows predicting successful puncture and catheterization using surrogate markers, such as dura mater displacement, epidural space widening due to drug injection, or mass movement of the drug within the caudal space. Although many experienced anesthesiologists still prefer to use conventional techniques, prospective randomized controlled trials using US guidance are providing increasing evidence of its advantages. The use of US-guided regional block will gradually become widespread in infants and children.

Morphologic diversities of sacral canal in children; three-dimensional computed tomographic study

BACKGROUND

Caudal block is a common technique in children for reducing postoperative pain, and there have been several reports on the variations of the sacral canal in children. However, previous studies have mainly focused on the needle trajectory for caudal block, and there is limited information on the structural variations of the sacrum in children. The purpose of this study was to analyze the anatomic variations of sacral canals in children.

METHODS

Three-dimensional computed tomographic images were analyzed. The data from the images included ① fusion of the sacral vertebral laminae and the sacral intervertebral space ② existence of the sacral cornua and ③ the types of sacral hiatus. The types of sacral hiatus were classified into 3 groups: group I (fusion of S3 or S4 vertebral laminae), group II (unfused vertebral arch with the distance of the S3 and S4 vertebral laminae < 50% of the distance between the cornua), and group III (unfused vertebral arch with the distance of the S3 or S4 vertebral laminae ≥ 50% of the distance between the cornua).

RESULTS

A total of 143 children were included in this study. All of the sacral vertebral arches were not fused in 22 children (15.4%). Cornua were not identified bilaterally in 5 (3.5%) and unilaterally in 6 (4.2%) children. In the sacral hiatus, group II and group III were identified in 22 (15.4%) and 31 (21.7%) children, respectively.

CONCLUSIONS

The sacral canal has various anatomical variations in children. Careful attention must be paid to identify the correct anatomic landmark.

The effect of flexion on the level of termination of the dural sac in paediatric patients

SUMMARY

Although the anatomy of the spinal cord and its associated structures have been well defined, the effects of body position relevant to neuraxial blockade have not been elucidated. This study was designed to determine the effect of body position on the end of the dural sac in children. After induction of anaesthesia, ultrasound examination was performed to evaluate the location of the dural sac end in the lateral position with a straight back and knee, and in the lateral position with the knees, legs, and neck flexed. The level of the end of the dural sac was determined in relation to the vertebrae. Our data demonstrate that the dural sac shifts significantly cephalad in the lateral flexed position used for neuraxial blockade (p < 0.001). These results suggest that the safety margin to avoid dural puncture during hiatal or S2-3 approach for caudal block can be increased in younger children.

The median approach to transsacral epidural block

Transsacral epidural block may be useful for surgery or cancer pain affecting the rectal, anal, or urethral region. The procedure through the dorsal sacral foramen is difficult because of the long insertion route. We investigated whether the transsacral epidural block could be simplified by using a median approach instead of a lateral approach through the foramen. Thirty patients for transurethral resection of bladder tumor had a catheter placed 5 cm cephalad at S2-3 (15 patients) or caudal (15 patients) epidural space using a 19-gauge Tuohy needle by the median approach. Lidocaine 2% 15 mL was administered for anesthesia. Anesthesia level (sensory block to cold), hemodynamics, and side effects were compared between the two approaches. The success rate of anesthesia was 87% for transurethral resection of bladder tumor (proximal anesthesia level higher than T10) and 100% for the sacral region (S1-5) in both groups. The highest level of anesthesia (median, T8 in the S2-3 group and T9 in the caudal group) was obtained in 20 min in both groups. No side effects were observed. We conclude that the median transsacral epidural approach is technically feasible in adults and presents an alternative to caudal block.

IMPLICATIONS

The median approach to transsacral epidural block has been described in children. We found that it is technically feasible in adults and presents an alternative to caudal block for procedures on the rectal, anal, or urethral region.