Interventional cancer pain: neurolysis, intrathecal therapy, cordotomy

Match the intervention to the pain pattern: sympathetic neurolysis for visceral pain in a defined territory, intrathecal drug delivery for widespread pain with dose-limiting opioid effects, and cordotomy for unilateral pain below the neck.

1. Visceral cancer pain: neurolysis by territory. Celiac plexus neurolysis targets upper abdominal viscera such as the pancreas; the superior hypogastric plexus serves the pelvic viscera; the ganglion impar serves the perineum, distal rectum and anus ¹.
2. Intrathecal therapy for severe or intolerable pain. ASPN states an implanted intrathecal pump is indicated when cancer pain stays severe despite adequate conventional medication or when dose-limiting side effects occur, and randomized trials and systematic reviews show analgesic efficacy and fewer opioid-related side effects ¹.
3. Cordotomy for unilateral pain below C4. Percutaneous cordotomy lesions the spinothalamic tract at C1–C2 contralateral to the pain, for intractable unilateral cancer pain below the C4 dermatome in patients with limited life expectancy; mesothelioma is a classic indication ²³.
4. Bilateral cordotomy is dangerous. Bilateral high cervical cordotomy carries much higher risk of severe complications, including respiratory depression; bilateral pain and severe respiratory dysfunction are listed as contraindications ²³.
5. Epidural clonidine needs a taper. Epidural clonidine is used with opioids for severe cancer pain, especially neuropathic pain; when stopping, taper over 2 to 4 days, because abrupt withdrawal has caused rebound hypertension and stroke ⁴.
6. Cord compression is an emergency. For metastatic epidural spinal cord compression, ASTRO recommends dexamethasone, and conditionally prefers surgery followed by radiation over radiation alone ⁵.

A neuroablative or neurolytic plan must fit the distribution: cordotomy cannot cover bilateral or midline pain, and celiac neurolysis will not relieve widespread bony metastatic pain ¹³.

• Neurolytic superior hypogastric plexus block gave satisfactory relief in 69% of patients in the original pelvic cancer series ⁶.
• Celiac neurolysis commonly causes transient diarrhea and can cause orthostatic hypotension ¹.
• Each spinothalamic tract carries pain from the opposite side of the body ³.
• Mirror pain after cordotomy is reported in 9% to 63% of patients ².
• Cordotomy spares light touch, which travels in the dorsal columns, so loss of all touch below the lesion is not an expected effect ².
• Intrathecal delivery allows oral opioids to be reduced or eliminated, with dramatic falls in serum opioid levels ¹.
• Bisphosphonates reduce skeletal events over time but do not treat acute cord compression ⁵.

• Offering a second, contralateral cordotomy to a patient with poor respiratory reserve ²³.
• Choosing celiac neurolysis for diffuse bone pain from widespread metastases ¹.
• Stopping epidural clonidine abruptly when the disease responds ⁴.
• Treating new back pain with neurologic deficit in spine metastases as routine pain instead of giving dexamethasone and arranging urgent surgery ⁵.