Thoracotomy Pain

• Segmental innervation from the thoracic spinal nerves, which branch into:
• Dorsal rami → innervates skin and muscles of the back
• Ventral rami → becomes the intercostal nerves
• Additional contributions from branches of the cervical plexus (supraclavicular nerves) and brachial plexus (thoracodorsal, long thoracic, medial & lateral pectoral nerves)


• Somatic afferents are conveyed by the anterior, lateral and posterior branches of the intercostal nerves to the ipsilateral dorsal horn of the spinal cord (T4 - 10)
• Visceral afferents are conveyed by the phrenic and vagus nerves, transmitting pain from injury to the bronchi, visceral pleura and pericardium

• Thoracotomy pain is both nociceptive and neuropathic in nature

• Nociceptive pain arises from multiple surgical processes in the perioperative period:


Aetiology of nociceptive pain from thoracotomy

Skin incision

Incision of muscles or pleura

Retraction of soft tissues and ribs

Visceral pain

Costochondral disarticulation or iatrogenic rib fractures

Presence of chest drains

Residual haemothorax



• Referred pain to the ipsilateral shoulder is also common after thoracotomy
• Results from irritation of the visceral pleural and pericardium
• Pain is referred to the shoulder by the phrenic nerve
• It is refractory to thoracic epidural analgesia as this will not reach C3-5 nerve roots

• Direct damage to the intercostal nerves
• Evolution of neuropathic pain via standard mechanisms

• The posterolateral approach to thoracotomy may involve division of latissimus dorsi, serratus anterior and trapezius muscles which is extremely painful
• Use of an anterolateral approach instead:
• Can still cause significant pain through damage of intercostal nerves and rib retraction
• Crosses multiple dermatomes so may be more uncomfortable than posterolateral incisions, which tend to be in a single deramatome


• VATS may reduce acute pain, although does not appear to reduce incidence of chronic pain
• May reduce acute post-operative pain by avoiding intercostal nerve damage e.g. fewer, smaller ports

• A multi-modal approach is optimal, especially owing to the multifactorial nature and multiple pain afferents involved, which preclude use of a single analgesic technique


• Regular simple analgesia e.g. paracetamol ± NSAIDs
• Use both intra- and post-operatively
• Reduce opioid requirements
• Treat ipsilateral shoulder pain, which is refractory to epidural analgesia
• Standard NSAID cautions apply, with the added consideration that they may reduce the efficacy of some pleurodesis procedures


• ɑ₂-agonists
• The thoracotomy PROSPECT guidelines don't recommend either clonidine or dexmedetomidine
• Conversely, the VATS guidelines recommend intra-operative IV dexmedetomidine


• Opioids
• 'Weak' opioids post-operatively for low-moderate intensity pain where simple analgesia is ineffective or NSAIDs contraindicated
• 'Strong' opioids, either PO or PCA, for rescue therapy post-operatively in those where regional techniques have failed or aren't possible


• Dexamethasone
• Single intra-operative 6.6mg dose sufficient to reduce pain scores, reduce pain on dynamic movement and provide opioid-sparing effect


• NMDA antagonists
• Magnesium may be associated with reduced opioid requirements and better post-operative spirometry values, but requires high doses to acheive this (intraoperative 50mg/kg bolus then 50mg/kg/hr infusion)


• Ketamine is also associated with reduced post-operative opioid requirement and better post-operative spirometry values, but it has not been robustly studied
• PROSPECT guidelines don't recommend its routine use, though it may have a place in patients with pre-existing chronic pain or long-term opioid therapy


• Gabapentinoids
• Not recommended for thoracic surgery by ERAS guidelines
• No evidence they reduce acute pain or provide opioid-sparing effect for thoracic surgery
• No evidence they reduce chronic post-surgical pain after thoracic surgery
• Regional anaesthetic techniques - see next section

• Paravertebral catheters may be inserted by either anaesthetists (percutaneous) or surgeons (thoracoscopically or via open incision)
• No difference in outcomes whether it's inserted under direct vision (surgeon) or ultrasound (anaesthetist)

• Paravertebral catheters are the PROSPECT-recommended 1^st line regional anaesthetic technique, over thoracic epidural, for both thoracotomy and VATS
• This is because of their non-inferior analgesia provision but with fewer adverse effects

• Thoracic (T5-6) epidurals benefit from a long track record and effective analgesia
• Typically a local anaesthetic + opioid infusion is used e.g.:
• 0.1ml/kg 0.25% levobupivacaine loading dose
• 0.1ml/kg/hr infusion of 0.1% levobupivacaine + 2μg/ml fentanyl
• May be difficult to insert owing to deep angle of spinous processes; a paramedian approach is often necessary
• Is the 2^nd line regional technique for thoracotomy analgesia, but isn't included in the VATS recommendations
• Issues include:
• Compared to paravertebral blocks, they're associated with increased incidences of hypotension, urinary retention, pruritus, and PONV
• The risk of significant complications e.g. epidural haematoma, epidural abscess and other complications of neuraxial anaesthesia
• Doesn't combat referred shoulder pain from the phrenic nerve

• This fascial plane block is the recommended 1^st line regional anaesthetic technique for VATS
• It is the 3^rd line technique for thoracotomy if the above techniques aren't available/contraindicated, although this is based on extrapolated VATS data rather than robust evidence


• It can be used as either a single shot block (e.g. 30-40ml 0.25% levobupivacaine) or a catheter-based technique
• It benefits from:
• Non-inferior to paravertebral block with regards to pain scores and opioid consumption at 48hrs post-op.
• Suitability in those on anticoagulant drugs, as it is classified as a 'superficial' block


• Issues include:
• Lack of familiarity/availability
• Inferior to paravertebral techniques with regards to pain (at rest and coughing) at 24hrs
• Less consistent effect on anterior thoracic pain
• May simply be a 'paravertebral block by proxy'

• Fascial plane block targetting the lateral cutaneous branches of the intercostal nerves
• Recommended as the 2^nd line regional anaesthetic technique for VATS
• It can be used as either a single shot block (e.g. 30-40ml 0.25% levobupivacaine) or a catheter-based technique


• Issues include:
• Less effective for posterolateral thoracotomy
• Less effective at reducing pain scores and opioid consumption compared to paravertebral or erector spinae blocks
• Risk of iatrogenic pneumothorax

• 4^th line technique for thoracotomy after paravertebral, thoracic epidural and erector spinae techniques
• Not recommended for VATS due to lack of procedure-specific evidence


• Issues:
• Inferior analgesia compared to above blocks
• Does not block dorsal rami so less effective for posterolateral thoracotomy incisions
• Higher risk of local anaesthetic toxicity than other techniques

• Intrathecal opioids
• No longer recommended owing to:
• The shorter duration of action (24hrs) than catheter based techniques
• Standard risks of IT opioids e.g. delayed respiratory depression, urinary retention etc.
• Theoretical benefit of being able to provide opioids alongside another regional technique in lieu of a thoracic epidural


• Intrapleural catheters
• No longer recommended owing to:
• Inferior analgesia compared to other techniques, in part due to dilution in the pleural space and erratic spread
• Considerable systemic absorption and risk of local anaesthetic toxicity