A comparison between anterior and posterior spinal implant systems.

In four patients with intractable pain from metastatic cancer, application of current through electrodes placed on the anterior surface of the cord produced analgesia and pain relief below the level of implant without the development of paresthesias. Application of current through electrodes placed on the dorsal columns in these patients also relieved pain, but to a lesser degree and with the development of associated paresthesias. In one patient, application of current from anterior electrodes to posterior electrodes produced a zone of dissociated sensory loss. While it is simpler to implant electrodes over the dorsal columns, the anterior location may be superior when currents are to be applied for the pain relief in the lower lumbar and sacral dermatomes.