Nerve Blocks
Neurologic Interventions
Management of Procedural Pain

Less-invasive analgesic approaches should precede invasive palliative approaches; however, for a minority of patients in whom behavioral, physical, and drug therapy do not alleviate pain, invasive therapies are useful.

Control of otherwise intractable pain can be achieved by the application of a local anesthetic or neurolytic agent. Nerve blocks are performed for several reasons:

• Diagnostic: To determine the source of pain (e.g., somatic versus sympathetic pathways).



• Therapeutic: To treat painful conditions that respond to nerve blocks (e.g., celiac block for pain of pancreatic cancer).



• Prognostic: To predict the outcome of long-lasting interventions (e.g., infusions, neurolysis, rhizotomy).



• Preemptive: To prevent procedure-related pain.

A single injection of a nondestructive agent such as lidocaine or bupivacaine, alone or in combination with an anti-inflammatory corticosteroid for a longer-lasting effect, can provide local relief from nerve or root compression. Placement of an infusion catheter at a sympathetic ganglion extends the sympathetic blockade from hours to days or weeks. Destructive agents such as ethanol or phenol can be used to effect neurolysis at sites identified by local anesthesia as appropriate for permanent pain relief and may also be used to cause destruction of central nervous system structures. The efficacy of neurolytic sympathetic blocks may vary depending on the underlying pain mechanisms involved. For patients with multiple pain mechanisms, neurolytic sympathetic blocks may serve as adjuvant techniques to analgesic medications.[1]

Neurosurgery can be performed to implant devices to deliver drugs or to electrically stimulate neural structures. Surgical ablation of pain pathways should, like neurolytic blockade, be reserved for situations in which other therapies are ineffective or poorly tolerated. In general, the choice of neurosurgical procedure is based on location and type of pain (somatic, visceral, deafferentation), the patient’s general condition and life expectancy, and the expertise and follow-up available.

Many diagnostic and therapeutic procedures are painful to patients. Treat anticipated procedure-related pain prophylactically and integrate pharmacologic and nonpharmacologic interventions in a complementary style.

Use local anesthetics and short-acting opioids to manage procedure-related pain, allowing adequate time for the drug to achieve full therapeutic effect. Anxiolytics and sedatives may be used to reduce anxiety or to produce sedation.

Cognitive-behavioral interventions, such as imagery or relaxation, are useful in managing procedure-related pain and anxiety. (Refer to the Cognitive-Behavioral Interventions ¹ section of this summary for examples of relaxation exercises.) Patients generally tolerate procedures better when they are informed of what to expect.

Offer the option for a relative or friend to accompany the patient for support.

References

1. Mercadante S, Fulfaro F, Casuccio A: Pain mechanisms involved and outcome in advanced cancer patients with possible indications for celiac plexus block and superior hypogastric plexus block. Tumori 88 (3): 243-5, 2002 May-Jun.  [PUBMED Abstract]