post thoracotomy pain

Dr Mehran Rezvani pain fellowship anesthesiologist & acupuncturist

Postthoracotomy Pain


Relevant Clinical Anatomy


Pain impulses from the skin, ribs, and parietal pleura are transmitted through the intercostal nervesfrom the visceral pleura through autonomic nerves from the lung through the vagus nervefrom the mediastinum, pericardial pleura, and diaphragm through the pherenic nerves


Clinical Presentation


During the Acute postoperative phase, patients experiencesharp pain that increases with breathing and coughing. The pain is also associated with numbness, especially along the scarsite


Chronic pain after thoracotomy is typically a combination of neuropathic and nociceptive pain

Burning pain and allodynia Aching chest or back painMyofascial pain (referred shoulder pain may occur, especially after procedures that cause injury to the diaphragm or the phrenic nerve)


Differential Diagnosis


Herniated discNeuroforaminal stenosisRib pathologyPostherpetic neuralgia Slipping rib syndromeCostochondritisTietze's syndromeMyofascial pain syndrome


Acute Pain Management for Patients UndergoingThoracotomy


Management of thoracotomy pain can be difficult, but thebenefits of effective pain control are significantSystemic opiatesRegional analgesicsNew oral and parenteral agents


Pain is a key component in the alteration of lung function after thoracic surgery

Postoperative analgesia to reduce pulmonary complications andattenuate the stress response


Almost 200,000 patients a year are diagnosed with bronchogeniccarcinoma, and nearly one-quarter of these patients will undergo surgical resection


Ineffective chest expansion due to pain may predispose toAtelectasisVentilation/ perfusion mismatchingHypoxemiaInfection


Thus, the goal of the clinician is to develop an analgesicregimen that provides effective pain relief to allow postoperativethoracotomy patients the ability to maintaintheir functional residual capacity by deep breathing


Effective clearing of secretions with cough and early mobilization can lead to quicker recovery and shorter length of hospital stay


Inadequate acute postoperative pain management may contribute tothe development of a chronic postthoracotomy pain syndrome(52%)

Acute pain after thoracic surgery predicts long-term post-thoracotomy pain. Clin J Pain 1996;12:50–5

Pathogenesis and management of persistent postthoracotomy pain. Chest Surg Clin N Am 1998;8:703–22


The pain associated with thoracotomy incisions can bedifficult to target and quantify, and prior studies have evaluated :

Chest tube painIncisional painVisceral painCoughing or movement


Systemic administration of opioids is the simplest and most common method to provide analgesia for postoperative pain

Unfortunately systemic opioid administration may not be adequatefor treating the intense postoperative pain associated with thoracotomy


Ketorolac, tramadol, COX-2 inhibitors, and ketamine are other potentially useful analgesic agents as alternatives or adjuncts to opioids


To improve the quality of analgesia, two classes of drugs canbe administered concurrently to obtain a synergistic analgesic effect while minimizing the side effects of each drug

Surgical technique itself can be modified in an attempt to reduce the impact of postoperative pain


Concepts in Postoperative Pain


Pain can be defined as an unpleasant sensory and emotionalexperience associated with actual or potential tissue damage


Local tissue damage results in inflammation and propagationof stimuli to the central nervous system

These stimuli are modulated by Excitatory [NMDA]) Inhibitory (opiate) pathways


Animal data have shown that administration of low doses of systemic morphine before noxious stimulation suppresses spinal cord hyperexcitability, whereas administration of doses after noxiousstimulation does not completely blunt it


Because the NMDA receptor has been implicated in the generationand maintenance of spinal cord “wind-up,” NMDA antagonists(eg, ketamine and dextromethorphan) are logical candidates for preemptive analgesia


Chronic Postthoracotomy Pain


Up to 50% of patients undergoing thoracotomy will develop chronic pain related to the surgical site

Chronic postthoracotomy pain has been defined as a continuousdysesthetic burning and aching in the general area of the incision that persists at least 2 months after thoracotomy

Surgical aspects of chronic postthoracotomy pain. Eur J Cardiothorac Surg 2000;18:711–6


Although no one surgical technique has been proven to decrease the incidence of chronic pain, intercostal nerve damage due to rib retraction seems to be involved in the development of the neuralgia

Preliminary findings in the neurophysicological assessment of intercostal nerve injury during thoracotomy.

Eur J Cardiothorac Surg 2002;21:298–301


Initiation of epidural bupivacaine/ morphine before surgical incision reduced the incidence of long-term pain[The effects of three different analgesia techniques on long-term postthoracotomy pain. Anesth Analg 2002;94:11–5]

Patients with increased postoperative pain had an increased incidence of chronic postoperative pain [Acute pain after thoracic surgery predicts long-term post-thoracotomy pain. Clin J Pain 1996;12:50–5]


Epidural Analgesia as the Mainstay of Postoperative Pain Management


Epidural analgesia has emerged as the analgesic technique of choice for postoperative thoracotomy pain management

Provide excellent pain control Avoids much of the sedation associated with systemic opiates Epidural Catheter allows for continued dosing postoperatively Avoids much of the motor blockade associated with intrathecal drug

administration


Much lower doses of drug administered in the epidural space are needed ( in compare with systemic administration )

Postoperative patients can consume on the order of 50 to100 mg of intravenous morphine during the first 24 hourspostoperatively when administered by a PCA device In comparison, epidural doses of 5 mg of morphine canprovide postoperative analgesia for 12 to 24 hours


Commonly used opioid–local anesthetic mixtures :Fentanyl-bupivacaineMorphine-bupivacaineFentanyl-ropivacaine


Epidural fentanyl 5 μg/mL combined with bupivacaine 0.1% providedan optimal balance between pain relief and side effects

WALDMAN 2011


TEA was effective in control of the incision pain but not effective inalleviation of postthoracotomy shoulder pain, which is mostlikely related to irritation of the pericardium or the pleura.


Patients receiving thoracic epidural analgesia for postthoracotomy pain, phrenic nerve infiltration with 10 mL of ropivacaine just before lung expansion and chest closure reduced the incidence and delayed the onset of ipsilateral shoulder pain by about 50% during the first 24 hours after open lung resection


Hypotension and urinary retention are common side effects related to TEA

Paravertebral block was found to be as effective as epidural block with local anestheticHowever, paravertebral block had a better side effect profile.


In many clinical settings, epidural analgesia is used as often as possible, whereas systemic analgesia is reserved for situations in which epidural analgesia is unsuccessful or contraindicated : CoagulopathyInfectionNeurologic disease


A meta-analysis of pre-emptive use of thoracic epidural analgesia concluded that it offered improved postoperative analgesia in the first 48 hours after surgery, but had no impact on chronic post-thoracotomy pain

Other techniques such as intrapleural analgesia, paravertebral block, cryoanalgesia, and infiltration at the incision site did not effect the incidence of post-thoracotomy pain syndrome


Postoperative epidural pain control may significantlydecrease pulmonary morbidity

The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, clinical trials. Anesth Analg 1998;86:598–612


Thoracic Versus Lumbar Catheters


Both lumbar and thoracic epidural catheters can be used for postoperative thoracotomy pain management

In majority of studies, no significant differences in analgesia andpulmonary function were seen; however, less opioid wasrequired in patients receiving thoracic epidural analgesia


In one study, thoracic epidural analgesia was associated with an increased incidence of ventilatory depression

Adverse effects of extradural and intrathecal opiates: report of a nationwide survey in Sweden. Br J Anaesth 1982;54:479–86


With thoracic epidural placement, the risk of injuring spinal cord tissue if the dura is inadvertently punctured is theoretically greater, and placement of a thoracic epidural catheter can be technically moredifficult due to the greater caudad angulation of the spinous processes


Patients who received epidural bupivacaine had a reduced incidence of supraventricular tachyarrhythmias when compared with patients whoonly received epidural opiates

Thoracic epidural bupivacaine attenuates supraventricular tachyarrhythmias after pulmonary resection.

Anesth Analg 2001;93:253–9


Thoracic epidural anesthesia (TEA) is the gold standard modality for pain control

WALDMAN 2011


Intercostal Nerve Block


Blockade of intercostal nerves interrupts C-fiber afferenttransmission of impulses to the spinal cord


A single intercostal injection of a long-acting local anesthetic can provide pain relief and improve pulmonary function for up to 6 hours


To achieve longer durations of analgesia, a continuous extrapleural intercostal nerve block technique has been developed in which a catheter is placed percutaneously into an extrapleural pocket by the thoracic surgeon


A continuous intercostal catheter allows frequent dosing or infusions of local anesthetic agents and avoids multiple needle injections


Shorter-acting local anesthetic, lidocaine, was just as effective as thelonger-acting agent bupivacaine

Cardiotoxicity of bupivacaine is far more dangerous than with lidocaine, especially in light of the fact that systemic absorption is great with an intercostal block


However, the advent of newer long-acting local anesthetic agents,including ropivacaine and levo-bupivacaine, has introduced new possibilities for prolonged analgesia with minimal cardiotoxicity


Extrapleural intercostal analgesiaor

Epidural analgesia?


In one study:Patients in the intercostal group required more supplemental morphineComparative study of continuous extrapleural intercostal nerve block and lumbar epidural morphine in post-thoracotomy pain. Can J Surg 1997;40:431–6”

In another study: With similar analgesia Vomiting, pruritus, and urinary retention occurring only in the epidural groupContinuous intercostal nerve block versus epidural morphine for postthoracotomy analgesia. Ann Thorac Surg 1993;55:377–80.


In one study:Both thoracic epidural analgesia and extrapleural intercostalanalgesia were safe and effective

Intercostal analgesia should be instituted in patients who do not qualify for thoracic epidural analgesia

Prospective, randomized comparison of extrapleural versus epidural analgesia for postthoracotomy pain. Ann Thorac Surg 1998;66:367–72


Intrapleural Analgesia


Local anesthetic agents can also be administered through a catheter positioned inside the pleural cavity as another modality to anesthetize intercostal nerves

The mechanism of action appears to be diffusion across the parietalpleura


There are inconsistent results in Interpleural analgesia studies:

Loss of local anesthetic through the chest tube Dilution of local anesthetic with blood and exudative fluid present in the pleural

cavity Binding of local anesthetic with proteins Altered diffusion across the parietal pleural following surgical manipulation and

inflammation


Nonsteroidal Anti-Inflammatory Drugs


Ketorolac is an NSAID available in a parenteral form, and it has been shown to be an effective adjunct agent to improve the quality of intercostal and epidural analgesia


Nonsteroidal anti-inflammatory drugs, however, have been associated with inhibition of platelet aggregation, gastrointestinal bleeding,and renal toxicity, limiting their usefulness in clinical practice


Blocking COX-1 activity alters platelet function and promotes gastrointestinal bleeding, whereas blocking COX-2 inhibits production of prostaglandins that mediate inflammation and pain-signalingtransmission


Oral celecoxib (Celebrex) and rofecoxib (Vioxx), and the parenteral parecoxib have been developed to relieve pain and lessen the risk of gastrointestinal bleeding


Tramadol


It binds to opiate receptors and inhibits epinephrine and serotonin reuptake, but lacks many of the side effects associated with other drugs with similar sites of action

Findings do provide an alternative to opiates


Ketamine


Ketamine confers analgesia by blocking the NMDA receptor

Side effects, however, including catecholamine release and significant cognitive impairment, limit the utility of this agent

Several authors suggest that ketamine may be a useful adjunct


Paravertebral Nerve Block


Paravertebral analgesia can be an effective alternative to epiduralanalgesia in thoracotomy patients


In one study in comparison analgesia through a thoracic epidural catheter,patients in the thoracic paravertebral group had lowerpain scores, less postoperative morphine consumption,and better preservation of pulmonary function


In addition,Side effects such as nausea, vomiting, urinary retention and hypotension were more problematic in the epidural group


Video-Assisted Thoracic Surgery


When compared with standard thoracotomy incisions, patients undergoing VATS had less postoperative pain and narcotic consumption in multiple studies


Phrenic Nerve Infiltration


Patients undergoing thoracic surgery frequently complainof ipsilateral shoulder pain due to diaphragmatic irritation

Infiltration of 10 mL of 1% lidocaine into the periphrenic fat pad atconclusion of surgery at the level of the diaphragm in patients undergoing thoracotomy significantly decreased incidence of ipsilateral shoulder pain and an overall reduction in pain score when compared with placebo infiltration


Cryoablation


Much of the pain associated with thoracotomy is mediatedthrough the intercostal nerves

Patients undergoing minithoracotomy for minimally invasive cardiac surgery benefited from cryoablation of the intercostal nerve at the completion of surgery


Chronic Post-thoracotomy Pain


The first reference to chronic post-thoracotomy pain was in 1944 by United States Army surgeons who noted ‘chronic intercostal pain’ in men who had thoracotomy for chest trauma during the Second World War


Chronic post-thoracotomy pain is defined by the International Association for the Study of Pain as pain that recurs or persists along a thoracotomy incision at least 2 months following the surgical procedure


It is typically burning and dysesthetic in nature and has many features of neuropathic pain

Post-thoracotomy pain also may result, at least in part, from a non-neuropathic origin (myofascial pain)


Incidence of post-thoracotomy pain as ranging from 25–60 % which makes postthoracotomy pain the commonest complication of thoracotomy

The majority of patients experience only mild pain, but 3–16 % experience moderate to severe pain


The risk of chronic pain following certain types of surgical procedures is increased in women and decreased in the elderly

Persistent postsurgical pain: risk factors and prevention.Lancet , 2006 367: 1618–1625


Two studies explored the role of preoperative anxiety/depression in relation to development of post-thoracotomy pain, both showing no relationship

A study exploring the role of intercostal nerve damage in chronic pain after thoracic surgery. Eur J Cardiothorac Surg 2006 29: 873–879

Acute pain after thoracic surgery predicts long-term post-thoracotomy pain. 1997, Clin J Pain 12: 50–55


Thoracotomy, along with limb amputation, is considered to be the procedure that elicits the highest risk of severe chronic postoperative pain

Pain has been reported more profoundly around the surgical site or scar


Others factorsNeuroma formationHealing rib fracture Frozen shoulderLocal infection/pleurisyCostochondritis/costochondral dislocationLocal tumor recurrencePsychological overlay


Injury of intercostal muscles, the serratus anterior, the latissimus dorsi, and the shoulder girdle muscles may cause significant myofascial painthat may even results in frozen shoulder


Pleurectomy is a strong risk factorSternal osteomyelitis Sternal fractureIncomplete healingSternocostal chondritisBrachial plexus injuryEntrapment of nerves from sternal wires


Even hypersensitivity reaction against the metal wires werefound to be other possible factors for development of PTPSafter thymectomy and coronary artery bypass surgery


Pathology


Tissue injury results in the release of local inflammatory mediators Peripheral sensitization

These actions activate intracellular signalling pathways on nociceptive terminal membranes reducing threshold and increasing excitability


This hypersensitivity reduces the intensity of theperipheral stimulus needed to activate nociceptors at the site of inflammation (primary hyperalgesia)


The hyperexcitable state of the spinal cord dorsal horn that follows release of humoral signals from noxious peripheral stimuli is referred to as central sensitization

Prolonged central sensitization can lead to long-lasting alterations in the central nervous system (CNS) and can contribute to chronic pain long after withdrawal of the acute painful stimulus


Thoracotomy is associated with surgical trauma to the intercostal nerves

Injured primary sensory neurons begin to fire action potentials spontaneously as a result of increased or novel expression and altered trafficking of sodium channels


This altered activity contributes to spontaneous pain, heightens pain sensitivity, and produces tactile allodynia


When a nerve is damaged, it heals by fibrosis and neuroma formation, which can lead to abnormal signal transduction and transmission to the CNS, generating both neuronal and glial responses, including the elevation of spinal prostaglandin (PGE2) concentrations


Although pre-emptive effects of gabapentinoids in reduction of postoperative morphine usage and opioid related adverse effects such as nausea, vomiting, and urinary retention have been established, their role in the prevention of long term pain has not been fully explored


Strategies for Treating Long Term Pain

Preventing and treating pain after thoracic surgery. Anesthesiology 104: 594–600


Study between radiofrequency of the dorsalroot ganglia, pulsed radiofrequency ablation of intercostalsnerves, and pharmacotherapy:Radiofrequency ablation (RFA) of the DRG is superiorto pulsed radiofrequency ablation of intercostal nerves andto pharmacotherapy


Because of the risk of RFA on the dorsal root ganglia, they recommended that such procedure be reserved for patients with intractable pain with failure of other conservative pain management approaches


Initial Hx & PE

At risk for recurrence or Anatomic Abnormality

NO

Physical therapy/Relaxation/

Psychological evaluation

CXR & CT SCAN

YES


Hypertrophic scarTrigger point,neuroma

NO

NSAIDS (SYSTEMIC OR TOPICAL)/ Tramadol /Topical caspaicine

Local anesthetic /+ steroid


Symptoms consistent With neuropathic pain

NO

Persistent pain YES

Consider TENS

YESTactile allodynia Topical lidocaine patch

NO

TCA or Anticonvulsants /considerNMDA Antagonists or calcitonin

Continue therapy, weaning as indicated


Candidate for opioid trial or nerve blocks? yes

Trial ofopioidtherapy

NOAcupuncture / Alternative therapies

Sympathetic component?YES

Sympathetic Block

Intercostal cryo / pulse RF

Intercostal Nerve BlockParavertebral Nerve blockThoracic Epidural Steroid Injection


Persistent pain? YES

Neuromodulation

NO

post thoracotomy pain

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