Paravertebral block

Last updated on 28 Aug 2025

In our relentless quest to find new and interesting places to shove local anaesthetic into our patients, we (or more accurately Hugo Sellheim) discovered the paravertebral block in 1905 for gynaecological procedures.

The technique was then largely shelved, presumably due to record numbers of unexpected pneumothoraces, until Eason and Wyatt picked it up again in 1979 for management of a variety of complex and chronic pain conditions.

Since the advent and widespread adoption of ultrasound the block has become safer and more popular, although it is finding stiff competition in its erector spinae cousin.

What are the alternatives to paravertebral block?

Epidural
Erector spinae plane block
Retrolaminar block
Midpoint transverse process to pleura block
Intercostal paraspinal block

The Anatomy

The paravertebral space is a strange anatomical location.

The blue bit looks worryingly close to the very fast red bit.

As you can see, and guess from the name, you're aiming just off to the side of the vertebra, into a potential space immediately posterior to the parietal pleura.

The goal is to block the spinal nerves as they emerge from the intervertebral foramen.

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You're essentially aiming for the transverse process, then heading a little lower and a little further in.

Describe the anatomy of the paravertebral space

A triangular wedge shaped space either side of the vertebral column
The anterolateral border is the parietal pleura
The posterior border is the superior costotransverse ligament
The medial border is the posterolateral aspect of the vertebral body, the intervertebral disc and intervertebral foramen

The thoracic paravertebral space is fairly continuous with loose connective tissue and fat, allowing cranial and caudal spread of injected local anaesthetic.

It will also spread to the epidural space medially and the intercostal space laterally.

A single injection should afford you four to six dermatomes of spread.

Caudal spread is limited by the origin of the psoas muscle.

What are the contents of the paravertebral space?

Fatty tissue
Intercostal vessels
Anterior rami of intercostal nerves
Dorsal rami of intercostal nerves
Sympathetic chain
White and grey rami communicantes

Tell me about the anatomy of the target nerves

There are eleven intercostals and one subcostal nerve (T12) on each side
These leave the intervertebral foramina and immediately divide into anterior and posterior divisions
The anterior divisions start between the pleura and posterior intercostal membrane, then pass between the inner and innermost intercostal muscles, then finish up as an anterior cutaneous branch of the thorax
The posterior divisions split into medial and lateral branches and supply the muscles and skin of the posterior chest wall

The vast majority of paravertebral blocks are thoracic blocks.

You can technically do a paravertebral block at a cervical or lumbar level as well, however there isn't any reliable communication between each vertebral level in these areas, so you don't get nearly as much spread of local anaesthetic, and end up having to do multiple injections.

So most practitioners tend to stick to thoracic.

The block

This versatile block has several tricks up its paravertebral sleeves:

It can be done uni- or bilaterally
It can be a single shot or a catheter with repeated doses or infusion
It can be done at a variety of spinal levels
It can be done when epidurals cannot (e.g. coagulopathy)

So how does it work?

We don't really know.

We know that the bolus injection of local anaesthetic enters the paravertebral space and swills around the rami communicantes, the sympathetic chain and the intercostal spinal nerves.

However it's probably doing other things as well:

Some is drifting medially into the epidural space, and acting as a low-dose thoracic epidural
Some is spreading laterally to the intercostal space, adding a cheeky smidge of intercostal block into the mix
Some of it slips north and some slides south to hit the vertebral levels above and below, usually two or three levels in each direction

Overall it doesn't really matter as long as the patient is comfortable and they don't have a raging pneumothorax.

What analgesia does a paravertebral block provide?

Ipsilateral
Segmental (depending on where you inject it)
Somatic and sympathetic

It's useful for both acute and chronic pain originating from one side of the thorax or abdomen.

What are the advantages of paravertebral block over epidural?

Similar pain relief
Fewer neurological complications - PDPH, radicular pain, paraplegia, nerve palsy
Less sedation, nausea and vomiting
Less cardiovascular instability
Much less urinary retention
No motor block of lower limbs
Better pulmonary function (as not bilateral) and fewer pulmonary complications
Can still be done when an epidural is relatively contraindicated (coagulopathy, systemic infection)

What are the surgical indications for paravertebral block?

Thoracotomy
Sternotomy
Breast surgery
Renal and Ureteric surgery
Cholecystectomy
Orchidopexy
Fundoplication
Appendicectomy
Hernia repair

Anything you might consider an epidural or spinal for, as long as it's only on one side, unless you're doing bilateral blocks.

What are the non-surgical indications for paravertebral block?

Rib fractures
Lung contusion
Benign and malignant neuralgia
Complex regional pain syndromes
Hyperhidrosis (sympathetic block rather than pain control)

What are the specific contraindications to paravertebral block?

Known malignancy in the paravertebral space
Empyema
Local infection over site of block
Known significant kyphoscoliosis or other anatomical abnormality
Complex or multiple thoracic surgical history that may distort anatomy

The Procedure

As with any regional anaesthetic procedure, you're going to start with the exasperatingly familiar exam answer of ensuring you have the following:

Informed consent
Correct site and side marked
IV access
Adequate monitoring
Emergency resuscitation equipment and drugs
Skilled assistance

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You'll be amazed how many FRCA marks have been awarded for this answer over the years.

What positioning options are there for this block?

Sat up leaning forward (ideal)
Prone
Lateral

At what level should you perform the block?

T4 for sternotomy (bilateral)
T6 for thoracotomy
T10 for abdominal procedures

For specific pain conditions, consider an injection at the dermatomal spinal level, plus further injections two spaces above and below.

Describe the landmark technique for a paravertebral block

Mark 2.5 to 3 cm lateral to the spinous process
Inject local anaesthetic
Advance Tuohy (or similar catheter needle) perpendicular to the skin
Contact the transverse process (usually around 4cm) and note that this is the transverse process of the vertebra below (because the thoracic spinous processes point steeply caudally)
Walk the needle superiorly or inferiorly off the transverse process
Use a loss of resistance technique, or advance at most 1.5cm to feel a pop as the superior costotransverse ligament is breached
Aspirate and cautiously inject local anaesthetic
Advance catheter (if used) to leave 2 to 3 cm in the paravertebral space

Describe the two commonly used ultrasound techniques

Longitudinal oblique

In plane technique
US probe is placed craniocaudal around 5cm from the midline
Ribs and pleura identified
Move probe medially until convex ribs change to square transverse processes
Rotate probe slightly so that cranial end is more medial and tilt probe slightly laterally
Advance needle in plane, caudally to cranially
After breaching the superior costotransverse ligament with the needle, injection of local anaesthetic will displace the pleura downwards

You can visualise this technique in the NYSORA video below.

Transverse