Anesthesia and Chronic pain management, Cape Breton Regional Hospital

I have no disclosures and do not receive any sponsorships from any of the companies that might be mentioned

Background – evolution in cancer care – earlier diagnosis, more effective treatment with increased survival.

WHO ladder approach-limitations in certain circumstances.

Multidisciplinary/multimodal approach – decision making.

The role of the ‘interventional procedure’.

Assessment is the key ? Tumor related ? Therapy side effects ? Chronic pain in cancer patients Psychosocial assessment Physical exam Directed studies

Realistic expectations Rarely eliminate “all pain” Spectrum of ‘success’:1. Improve QOL2. Reduce medication including side effects3. Avoid complications4. Obtain thoughtful, realistic informed

consent (including family)

Radiation: Conventional/Stereotactic Biphosphonates: MOA-supresses osteoclast

mediated bone resorption, eg IV zoledronic acid Radiopharmaceuticals: samarium, strontium Danosumab: (RANKL-Ab) – osteoclast maturation

inhibitor Hormonal therapies: prostate/breast Orthopedic treatments: Bracing/Surgery/PMMA

injection

60-80% well addressed by oncologists

Poorly controlled group – who to call?1. Depends on the problem2. Depends on local

expertise/availability3. Depends on patient preferences4. But call someone!!

Traditional/Etiologic: Nociceptive vs. Neuropathic

New Challenge: ‘Acute’ vs. ‘Chronic Cancer Pain’ Pain Throughout the cancer cycle:1. Pain at diagnosis2. Painful diagnostic procedures and/or resective

surgery3. Pain due to chemo/radiation4. Painful progression/metastasis

WHO 30 years on – time for critical reappraisal ? Treatments available in 1982 Lack or efficacy Not evidence based Long-term opioid efficacy and side effects

problematic Mechanism based, individualized approaches

important Last resort WHO options offer better pain

control/fewer side effects Pain problematic throughout cancer cycle –

prevent chronic pain by addressing acute pain better

Treat pain early to prevent morbidity Use adjuvants/procedures/physical

medicine techniques early to avoid morbidity and transition to chronic pain

Adopt chronic pain treatment strategies early in the cycle

‘Consider’ intervention the fourth step in the WHO ladder approach

No rules exist for the timing of interventional procedures – it is your call

“Incidental” Nature Peaks/Valleys hard to capture Bracing challenging Surgical options may be limited r/t

overall debility “Snowball effect” of debility to

morbidity to mortality

Multidisciplinary care Primary care, pain specialist, physical medicine,

surgeon, psychologist, palliative care physician, physical therapist, occupational therapist, social work, chaplin

Multimodal Care Adjuvant medications Procedures/injections/RF/implantables, etc. Opioids Topicals Holistic approaches

When:1. Refractory to usual management2. Unacceptable side effects from

analgesics e.g. opiate induced hyperalgesia and myoclonus

Which:1. Neuraxial infusions2. Other pain procedures: Nerve blocks,

neurolytics, radiofrequency, vertebral augmentation, etc …

Neuraxial Treatment indicated in:1. Intolerable side effects of existing

oral/intravenous management2. Inadequate analgesia on oral intravenous

management Options:

Tunneled/temporary epidural or plexus infusions

Refractory Cancer PainLife expectancy ≤ 3 months1. Need for local anesthetics (e.g. chest wall mass)

anticipated2. Need for high dose LA

Epidural catheter (tunneled e.g. Du Pens)Diffuse pain, epidural space obliterated, need for IT PCA/

unavailability of programmable pump

Intrathecal catheter (tunneled e.g. Du Pens)

Life expectancy ≥ 3 monthsSomatic / visceral pain

Single Shot IT trialNeuropathic Pain Equivocal results

IT Catheter Trial≥ 50% pain relief ≤ 50% pain reliefImplant pump Further medical

management

Retrospective review (baseline vs. 3 months)60 months, N=160138 available at 3 months

Numerical pain scores reduced:7.09 ± 1.8 to 3.7 ± 2.4 (p<0.001)

Oral opioid intake declined 577 mg/d to 206 mg/d MOED (p<0.001)

Drowsiness/mental clouding decreased:- 5.4 to 2.9/10 and 4.5 to 2.5/10

Zhuang M et al, IARS 80th Congress March 2006, San Francisco, CA

N = 300 Serious infections approx 10; 5 pump

explants (< 2%) Paralysis 1 (<< 1%) Revision rate/catheter, etc: 5 – 10%

Meta-Analysis Superficial infection 2.3% Deep infection 1.4% Every 71st patient will have an infection after 54

days of therapy Bleeding 0.9% Neurological injury 0.4%

Aprili D et al, Anesthesiology 2009

1. Likely to help2. Focal pain3. No contraindications

Neurolytic blocks (alcohol, phenol or glycerol)where motor/sensory separation exists. Consider local block first

RF ablation (nerves/tumor)? Role of pulsed RF Vertebral augmentation Plexus blocks Simple injections

Cancer patients can have coexisting VCF’s Trend is towards ignoring these fractures This is possibly benign neglect Quick and relatively affordable procedure

with excellent results and pain relief NEJM article condemning vertebroplasty had

poor design and statistics. It compared vertebroplasty to poorly (non-ISIS standard) performed medial branch blocks

Role of vertebroplasty vs. kyphoplasty vs. the significant discrepancy in procedural cost vs. benefit

Indicated for intractable pain after failure of less invasive procedures in patients with a short life expectancy

May provide profound pain relief for pelvic malignancies at the cost of bladder and bowel control

Never the first treatment of choice Experience very limited in the current

environment A valuable tool however, should not be

discounted

Severe intractable pain Intolerable side effects of analgesic therapy Intrathecal catheter not an option Advanced/terminal malignancy Pain well localized – unilateral, localized

trunk or involving only a few dermatomes Primary somatic pain mechanism Absence of intraspinal tumor spread Pain relieved with prognostic local block Realistic expectations by patient and family Patient clearly understands possible side

effects

Quality of analgesia might be less than after local anesthetic

Duration of effect not permanent Requires downward titration of opiates Lack of procedural skill in physician pool Potential for long term complications Neuropathic pain and dysesthesias Analgesic failure – incomplete block,

wrong neural target New pain at distal site

Celiac plexus block – relieves pain from intra abdominal viscera excluding left colon and pelvic content

Superior hypogastric plexus block – manages visceral component of pelvic pain

Ganglion Impar block – manages persistant burning associated with pelvic pain

Intercostal blocks – manages chest wall malignancy

Gasserian block – manages trigeminal tumor infiltration pain

Meticulous selection significantly increases success

Inferior to intrathecal pumps, cost of the latter often prohibitive – visible versus invisible cost

Both alcohol and phenol are cheap Possible future resurgence of these

techniques due to increasingly hostile financial environment

Do not allow perfect to be the enemy of good