Thoracic Paravertebral Block: Still the Standard, Newly Matched

The thoracic paravertebral block deposits local anaesthetic in the wedge-shaped space beside the vertebral body, where the spinal nerve emerges before it divides. Because the block catches the nerve at that point, a single injection can produce unilateral somatic and sympathetic blockade across several dermatomes — something no single fascial plane injection reliably achieves.

It has long been regarded as the reference standard for unilateral chest and breast wall analgesia. The interesting development is that the newer, easier blocks have now caught up with it on most outcomes, and the guidelines have started saying so. This reference sets out the anatomy, the current evidence position, and the safety considerations. It sits under our clinical reference to nerve blocks in outpatient pain practice.

The space, and what makes it different

The thoracic paravertebral space is bounded anterolaterally by the parietal pleura, posteriorly by the superior costotransverse ligament, and medially by the vertebral body and intervertebral foramen. Within it lie the spinal nerve, its dorsal ramus, rami communicantes and the sympathetic chain.

Two consequences follow. First, blockade includes the sympathetic component, which is why the technique has a role where sympathetic interruption is wanted rather than incidental. Second, the space communicates both cranially and caudally, so injectate spreads to adjacent levels — and communicates medially with the epidural space, which is the source of its most important complication.

What the current guidelines say

The 2026 PROSPECT update for major oncological breast surgery reviewed 176 randomised controlled trials and eight systematic reviews using a modified Delphi process weighing invasiveness, efficacy and adverse effects.

It recommends single-shot thoracic paravertebral block — alongside erector spinae plane block, interpectoral and pectoserratus plane blocks, serratus anterior plane blocks and local infiltration analgesia — and states that the listed single-shot regional techniques are considered equivalent to each other. It explicitly no longer recommends a continuous thoracic paravertebral block, on the reasoning that single-shot techniques are sufficient to cover the worst part of the acute pain trajectory.

A 2026 network meta-analysis of 103 randomised trials in mastectomy reached a compatible but slightly different conclusion: paravertebral block showed the most consistent benefit across outcomes, particularly opioid consumption and postoperative pain, with fascial plane blocks comparable on most outcomes but paravertebral superior for pain on movement. Serious complications were rarely reported in either group.

The defensible reading is that paravertebral block remains at least as good as anything else and marginally better on dynamic pain, while being technically harder and carrying a complication profile the fascial plane blocks do not. That trade is why a practice might reasonably choose either.

The complications that define it

Three matter, and they follow from the anatomy rather than from operator error alone.

• Pleural puncture and pneumothorax — the pleura forms the anterolateral boundary of the target space.
• Epidural or intrathecal spread — the space communicates medially through the intervertebral foramen, so injectate can reach the neuraxis. This is the reason bilateral blocks and large volumes require particular care, and why hypotension after an apparently unilateral block should prompt reassessment rather than reassurance.
• Vascular puncture and systemic absorption — the space is vascular, and multi-level or bilateral technique multiplies the dose.

Because the block reaches the neuraxis in a proportion of cases, anticoagulation status is treated with the caution applied to neuraxial procedures rather than to peripheral ones — a distinction between society documents that is routinely confused, and which is set out in the nerve blocks reference.

What ultrasound changed

The classical technique relied on loss of resistance after contacting the transverse process, with depth inferred rather than seen. Ultrasound allows the pleura, the transverse process and the superior costotransverse ligament to be identified directly, and the downward displacement of the pleura on injection provides immediate confirmation that the injectate is in the right space.

As everywhere in this field, the honest claim for guidance is accuracy and safety rather than better pain relief, which is the distinction drawn in musculoskeletal ultrasound for pain practice.

For clinicians

This is a deep block adjacent to the pleura and in communication with the epidural space, and it is acquired under supervision. This reference carries no needle depths, angles or volumes for that reason.

Empire teaches the paravertebral nerve block under ultrasound guidance within Advanced Musculoskeletal Ultrasound Guided Injections, part of the pain management academy.