Anesthetic Techniques

Anesthetic techniques are indicated in a small percentage of patients with cancer pain and are usually indicated as an adjunct to standard oral narcotic administration. However, in certain select patients early intervention can be of considerable benefit.

In the management of pain symptomatology, it is the balance between symptoms versus the side effects and complications of therapy. This is especially true when irreversible invasive techniques are used, such as neurolysis.

• A broad spectrum of pain can be managed by invasive procedural means, but the functional price paid may be inordinately high
• Methods that are well established and are predictable should be used; procedures based on hope and not experience should be avoided
• Pain due to denervation will, in general, not be improved by further denervation
• A well conceived and executed procedure that fails, and further attempts at the same, should be avoided as they too will likely fail
• No procedure exists for the affective, suffering component of pain
• The timing of procedures is critical
• Invasive procedures should be avoided in benign pain syndromes
• Local anesthetics and neurolytic drugs (alcohol or phenol) are in general nonselective in their actions on neural tissue and relative benefits will depend on the volume, concentration and site of administration of the drug
• Anesthetic techniques may be diagnostic or therapeutic

Commonly performed procedures are:

1. Trigger point injections: In the management of myo-fascial pain syndromes (often found in association with plexopathies), minimally invasive, vary from dry needling to infiltration with local anesthetics
2. Sympathetic blockade: More invasive, requires operating room facilities
   • Early blockade is suggested, although difficult to predict who may obtain a beneficial result
   • Indicated in plexopathies (especially stellate ganglion block in brachial plexopathies) sympathetic dystrophies, deafferentation pain syndromes, and in the acute pain of herpes zoster lesions, where not only may one decrease acute pain, but decrease the incidence and intensity of post herpetic neuralgia
3. Coeliac plexus blockade: Indicated in management of visceral pain such as that from pancreatic carcinoma
   • Highly efficacious block and it is not infrequent that a neurolytic procedure will provide pain relief for up to three months and the block may be repeated. Most frequent side effect is postural hypotension
   • Requires operator skills and facilities
4. Peripheral nerve blocks: Often diagnostic - of limited long term benefit except intercostal nerve blockade where neurolysis may be beneficial
5. Epidural Blockade: May vary from single administration of drug to continuous infusions via an indwelling catheter
   • Indicated for control of severe pain usually below T6 level
   • Local anesthetics may be helpful with neurogenic pain. Epidural narcotic administration may decrease narcotic related side effects as considerably smaller doses are required than when drug used orally. This route of administration requires ongoing management by anesthesia
   • Epidural or subarachnoid neurolysis may be beneficial in certain patients with intractable neurogenic pain
   • As in all procedure related therapies, the success of the procedure depends not only on the skill and judgement of the operator, but also on the patients' expectations and overall understanding of their pain and disease process

Neurosurgical Procedures

Ablative procedures, usually percutaneous cordotomy, are useful in certain instances of severe pain due to cancer when more conventional methods fail.

Cordotomy is done for unilateral pain below the low cervical-upper thoracic region; a common problem is unmasking of pain on opposite side of body after cordotomy is done; cordotomy should not be done on patients likely to survive beyond a year as pain tends to recur; careful patient selection is important.

Other neurosurgical procedures such as rhizotomy, dorsal root entry zone lesions, mesencephalic tractotomy, thalamotomy, pituitary ablation, etc. are best left to the discretion of the neurosurgeon who is experienced and knowledgeable about cancer pain management; many of these procedures are risky and radical for patients already seriously ill.

Physiotherapy

Various treatments of this type help in relief of pain due to cancer, for example:

1. Hot/ cold packs and/or massage may help muscle spasm pain secondary to metastases in spine or long bones; passive exercise may be indicated
2. Neck pain with cervical muscle spasm related to cervical vertebral metastases may be relieved by collar
3. Immobilization of painful limb by splint or support of painful spine by corset may help
4. Mobilization may be improved and pain lessened by using crutches, canes, walker
5. Trans-cutaneous stimulation (TENS) is a method of pain treatment which delivers a small electrical stimulus to the skin; it may be useful in certain types of pain due to partial nerve damage (e.g. post-herpetic neuralgia, post-surgical pain, post-irradiation pain); pain due to metastatic disease usually requires much more aggressive treatment

Relaxation Techniques

Breathing exercises, hypnosis, biofeedback, visual imagery, distraction, massage, hydrotherapy, music therapy and many other relaxation techniques are helpful in pain management.

Acupuncture

Certain individuals appear to respond to this technique but there is still no large series reporting significant benefit of chronic pain of cancer with acupuncture. Pain due to metastatic disease requires much more aggressive treatment and pain related to treatment of cancer (i.e. post-surgical, post-chemotherapy, etc.) remains difficult to treat and, in most cases, is unresponsive to acupuncture.