A cadaveric study of thoracic paravertebral spaces from the point of view of paravertebral block

Abstract

Background: Paravertebral block (PVB) is a regional anesthetic technique, in which a local anesthetic is injected into the thoracic PVS, resulting in ipsilateral somatic and sympathetic nerve blockade. Objectives: The present study aimed at observing the extent of thoracic paravertebral space (TPVS) at the levels of T1–2, T6–7, and T11–12 by measuring the horizontal and vertical spread of the dye in the Indian population. Materials and Methods: Methylene blue dye was injected into the TPVS at the levels of T1–2, T6–7, and T11–12 and its spread observed. Results: A total of 25 cadavers were studied. The extent of horizontal the spread was average of 83.0 mm at the level of T1–2, 103.0 mm at the level of T6–7, and 88.2 mm at the T11–12 level. The average vertical spread in the intercostal space at the level of T1–2 was found to 48.1 mm, at the level of T6–7 was found to be 44.6 mm, and at the level of T11–12 was found to be 55.04 mm. The maximum vertical spread of dye was over three intercostal spaces. Sixty-four percent of the cadavers studied showed a spread of dye from TPVS to lumbar paravertebral space. In 20% of the cadavers, a contralateral spread of injected dye was observed. The average depth of the needle to reach the TPVS was observed to be 36.8, 35.7, and 36.1 mm for T1–2, T6–7, and T11–12, respectively. Conclusions: A paravertebral block (PVB) has immense potential in regional anesthetic techniques involving thoracic and lumbar dermatomes. The present study will be helpful for surgeons and anesthesiologists to reduce uncertainties of the spread of anesthetic agents in thoracic PVB and its complications.