Ultrasound-guided thoracic parvertebral blocks: anatomy, approaches and techniques

Thoracic parvartebral blockade is a century old technique used for intra-operative and peri-operative pain control as well as acute and chronic non-operative pain. Although not used for many decades, this block has enjoyed a resurgence of interest over the past twenty years. Clinical benefits include the following: thoracic paravertebral blockade may be unilateral or bilateral, motor blackade is very rare, orthostatic hypotension is rare, there is little risk of urinary retention, the block may be performed as a single shot or by placement of an indwelling catheter, and a patient's opioid requirement may be decreased markedly. Many practitioners, however, remained hesitant to perform thoracic paravertebral blocks secondary to the associated risk of pneumothorax, reported to be 0.5%-2% in addition to the risk of dural puncture with some of the older medially directed landmark approaches.