CORDOTOMY

A cordotomy involves destruction of pain fibers in the anterolateral quadrant of the spinal cord (where the sensory fibers run in the spino-thalamic tract) resulting in contralateral analgesia (pain fibers cross to the opposite side of the cord). Surgical cordotomy was described in 1912. Percutaneous cervical cordotomy (PCC) was introduced in 1963.

Cordotomy is rarely required. The only indication is severe unilateral cancer pain below C5 unresponsive to analgesia or other techniques. The effect can wear off after several months. It is usually only indicated when the prognosis is short. (Its successful use requires considerable expertise, and it is an infrequent procedure even at major medical centers.)

About 80% of patients get good long-term pain relief, in expert hands. In some people not all the sensory fibers cross over in the cord, which explains why pain relief can be partial.

PCC is performed under local anesthetic and fluoroscopic x-ray control. A needle is inserted (just below the mastoid process) via the C1-C2 space into the spinal cord. Its position is checked by electric stimulation of the needle which should cause sensory changes in the contralateral half of the body. A radio-frequency electric current then produces a heat lesion. The power is increased until the area of analgesia covers the whole painful area.

«  The patient has to be able to talk and cooperate during the procedure.

The procedure has a 6% mortality rate and several complications:

• Numbness and tingling - 100%

• Horner’s syndrome - 100%

• lpsilateral weak leg - 40%

• C2 neuritis - occasional

• Urination affected - rare

• Respiration affected - rare

• Ataxia - very rare

• Impotence - very rare

Motor weakness can occur due to damage to the corticospinal tracts.

Urination can be affected (especially if a pelvic tumor has already damaged bladder nerves). Cordotomy is performed contralateral to the tumor and the pain.

There is often a short-lived weakness in the muscles of one side of the body which can adversely affect respiration, especially if the patient has chronic obstructive pulmonary disease (COPD). Bilateral cordotomy is avoided because of the danger of Ondine’s syndrome (loss of the involuntary breathing reflex and, therefore, resultant inability to sleep).

Morphine should be stopped following a cordotomy, then re-titrated (starting with low doses) if some pain persists. This prevents possible occurrence of respiratory depression. (see Morphine)

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