Anesthetic Techniques for Control of Cancer Pain

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Anesthetic Techniques for Control of Cancer Pain

• William S. Blau
• Director of Pain Medicine
• Department of Anesthesiology
• University of North Carolina

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Multimodal Interventions

• Antineoplastic
• Chemotherapy
• Radiotherapy
• Surgery
• Pharmacological
• Neurostimulatory
• Neuroablative
• Anesthetic
• Physiatric
• Psychologic

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Indications

• Pain refractory to pharmacological therapy
• Pharmacological therapy limited by side effects
• Pancreatic and other visceral cancers
• Acute relief for pain emergencies
• Diagnostic

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When is Pain Refractory?

• What about additional antitumor therapy?
• Is maximum dose ever a criterion?
• How many trial rotations of alternative
  analgesics are required?
• What constitutes sufficient effort at controlling
  side effects?
• Adequate trials of adjuvant drugs?

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Local Anesthetic Blocks

• Indications
• Diagnostic
• Prognostic
• Acute relief
• Sympathetically maintained pain
• Herpes zoster and postherpetic neuralgia

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Local Anesthetic Blocks

• Types
• Trigger point injections
• Peripheral nerve blocks
• Continuous catheter techniques

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Neurolysis

• Advantages
• Potentially excellent pain relief
• Long lasting
• Few collateral effects outside of treated region
• Reduced dependence on chronic systemic therapy
• Relatively low long term cost and care
  requirements

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Neurolysis

• Disadvantages
• Can cause numbness, paralysis
• Not permanent
• Not always effective
• Burning pain with alcohol
• May not eliminate the need for systemic
  analgesics
• Complications

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Neurolysis

• Side effects/complications
• Unintended non-neurologic injury
• Sensorimotor deficit/autonomic dysfunction
• New neuropathic pain

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Neurolysis

• Relative indications
• Severe, persistent pain that is well localized
• Pain is well characterized and consistent
• Somatic/visceral rather than neuropathic
• Short life expectancy
• Candidate for spinal opioid therapy

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Neurolysis

• Relative contraindications
• Severe psychological distress
• Compromised cognitive function
• Other considerations
• Management of concurrent opioid therapy
• Role of prognostic blocks

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Mechanisms of Neurolysis

• Chemical agents
• Phenol
• Ethanol
• Lidocaine 5
• Physical agents
• Cold (cryoanalgesia)
• Heat (radiofrequency)

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Celiac Plexus Block

• Applications
• Pancreas
• Renal or liver capsule
• Spleen
• Stomach
• Colon
• Success rate 80-94

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Celiac Plexus Block

• Complications
• Diarrhea
• Orthostatic hypotension
• Spinal cord syndrome

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Subarachnoid Neurolytic Block

• Complications
• Post dural-puncture headache
• Bowel, bladder, muscle paresis
• Sensory impairment
• Dysesthesias
• Arachnoiditis
• Infection

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Neurosurgical Methods

• Percutaneous cordotomy
• Dorsal root entry zone lesions
• Midline C1-2 myelotomy

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Neuraxial Opioid Analgesia

• Dose/efficacy relative to systemic opioids
• Reduced side effects
• Selective analgesic effect

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Neuraxial Opioid Analgesia

• Other benefits
• Reliable, cost effective screening
• Titratable
• Applicable for wide variety of pains/patients
• Effective for pain not amenable to neurolysis
• Cost effective?
• Reversible

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Neuraxial Opioid Analgesia

• Indications
• Efficacy in descending order
• Adequate resources available
• Adequate life expectancy
• Successful trial of therapy

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Neuraxial Opioid Analgesia

• Contraindications
• Coagulopathy
• Sepsis
• Local alteration of skin
• Altered mental status
• Noncompliance

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Neuraxial Opioid Analgesia

• Disadvantages
• Clinical
• Limited efficacy for opioid-insensitive pain
• No PCA potential in some instances
• Possible systemic effects
• Possibility of tolerance

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Neuraxial Opioid Analgesia

• Disadvantages
• Technical
• Requires minor surgery
• Cost
• Commitment
• Practitioner requirements training and support
  system

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Neuraxial Opioid Analgesia

• Side effects/complications
• Respiratory depression
• Gastrointestinal constipation, nausea/vomiting
• Urinary retention
• Pruritis
• Mental status effects
• Hyperesthesia
• Equipment failure
• Infection
• Catheter migration

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Implanted Catheters for Neuraxial Delivery

• Epidural benefits
• Cost effective in short term
• Less risk of spinal headache
• Less chance of meningitis
• Wider selection of agents with greater ease of
  titration
• Commercial concentrations of clonidine or
  bupivacaine are available

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Implanted Catheters for Neuraxial Delivery

• Intrathecal benefits
• Technically easier to locate intrathecal space
• Loss of epidural efficacy due to fibrosis
• Lower injectate volumes required
• Catheter migration less risky

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Neuraxial Infusion

• Selection of infusate
• Morphine
• Other opioids
• Clonidine
• Local anesthestics
• Mode of delivery
• Continuous infusion
• Bolus