Measuring the depth of the caudal epidural space to prevent dural sac puncture during caudal block in children.
BACKGROUND
Caudal blocks are performed through the sacral hiatus in order to provide pain control in children undergoing lower abdominal surgery. During the block, it is important to avoid advancing the needle beyond the sacrococcygeal ligament too much to prevent unintended dural puncture. This study used demographic data to establish simple guidelines for predicting a safe needle depth in the caudal epidural space in children.


METHODS
A total of 141 children under 12 years old who had undergone lumbar-sacral magnetic resonance imaging were included. The T2 sagittal image that provided the best view of the sacrococcygeal membrane and the dural sac was chosen. We used Picture Achieving and Communication System (Centricity®PACS, GE Healthcare Co.) to measure the distance between the sacrococcygeal ligament and the dural sac, the length of the sacrococcygeal ligament, and the maximum depth of the caudal space.


RESULTS
There were strong correlations between age, weight, height, and BSA, and the distance between the sacrococcygeal ligament and dural sac, as well as the length of the sacrococcygeal ligament. Based on these findings, a simple formula to calculate the distance between the sacrococcygeal ligament and dural sac was developed: 25 × BSA (mm).


CONCLUSIONS
This simple formula can accurately calculate the safe depth of the caudal epidural space to prevent unintended dural puncture during caudal block in children. However, further clinical studies based on this formula are needed to substantiate its utility.
Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
Hyun Jeong
HJ
Lee
Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
Ji Young
JY
Min
Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
Hyun Il
HI
Kim
Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
Hyo-Jin
HJ
Byon
D000367:Age Factors; D000465:Algorithms; D000763:Anesthesia, Caudal / Q000009:adverse effects* / Q000379:methods*; D001827:Body Height; D001830:Body Surface Area; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D004388:Dura Mater / Q000293:injuries*; D004824:Epidural Space / Q000033:anatomy & histology* / Q000000981:diagnostic imaging* / Q000254:growth & development; D005260:Female; D006801:Humans; D007223:Infant; D008022:Ligaments / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D009339:Needles; D012189:Retrospective Studies; D012445:Sacrococcygeal Region / Q000033:anatomy & histology / Q000000981:diagnostic imaging
anesthesia, caudal; anesthesia, regional; child; epidural space; magnetic resonance imaging; needles