Spread of dye after single thoracolumbar paravertebral injection in infants. A cadaveric study.

BACKGROUND

Thoracolumbar paravertebral block (PVB) is one method of providing regional anaesthesia for abdominal wall surgery in children. It is common practice when performing a PVB for abdominal wall anaesthesia to inject a certain volume of local anaesthetic solution in the paravertebral space at several levels. This increases the duration of the procedure and makes it more invasive.

OBJECTIVES

To determine the character of dye spread in infants' paravertebral space, to check the feasibility of single injection PVB and to determine the optimal volume of injectate necessary to cover the paravertebral segments responsible for sensation of the lower abdomen.

DESIGN

Experimental study.

SETTING

Single centre, University Hospital, April 2013 to August 2013.

SUBJECTS: Twenty infant cadavers.

INTERVENTION: Ultrasound-guided, single thoracolumbar paravertebral injections were performed on infant cadavers.

MAIN OUTCOME MEASURE: The total number of paravertebral segments stained after dye injection and specific vertebral levels of cephalad and caudad spread of dye in the paravertebral space.

RESULTS

Dye was present in the paravertebral spaces of all cadavers. Spread of dye within the paravertebral space was different depending on dye volume. Strong correlation was found between the volume of injectate and the number of paravertebral segments involved. The number of spinal nerve roots surrounded with dye corresponded with the number of paravertebral segments involved. T11, T12 and L1 nerve roots were stained in all cadavers. The optimal injectate volume to involve T10-L1 segments was defined as 0.2 to 0.3  ml  kg(-1).

CONCLUSION

Single thoracolumbar paravertebral injection at T12-L1 level leads to caudad and cephalad spread of injectate in a dose-dependent manner. Single injection thoracolumbar paravertebral injections could be performed for lower abdomen anaesthesia in infants. We suggest that a single injection of 0.2 to 0.3  ml  kg(-1) of local anaesthetic in the thoracolumbar paravertebral space could provide adequate coverage of the dermatomes of the lower abdomen.