Subarachnoid adrenal medullary transplants for terminal cancer pain: A report of preliminary studies

Abstract

Background: The prolonged use of opioids to treat intractable pain with currently available therapeutic modalities is often unsatisfactory, usually because of tolerance or complications. Extensive studies carried out in the authors' laboratories have indicated that the transplantation of adrenal medullary tissue into the spinal subarachnoid space can significantly reduce pain in animal pain models, most likely via release of opioid peptides and catecholamines. The current study was undertaken to assess the feasibility and efficacy of subarachnoid adrenal medullary transplantation in alleviating terminal cancer pain in humans. Methods: Two milliliters of human adrenal medullary tissue were prepared in the laboratory and then transplanted via lumbar puncture into the subarachnoid space in five patients suffering from terminal cancer pain. Pain scores (VAS), functional activity, and opioid intake were assessed and recorded before and after the transplantation procedure. In addition, CSF samples were collected before and (when possible) at fixed intervals after transplantation for biochemical and cytologic analysis. Results: Four of the five patients demonstrated progressive decreases in pain scores after the transplant procedure, with concomitant reductions in opioid intake. Three of these four patients remained pain free, two for over 10 months, while the other had a recurrence of her pain after surgery for spinal cord compression secondary to metastases 10 weeks after transplant. The fifth patient had no pain reduction by 1 month after the procedure, and refused further followup. After the transplants, spinal CSF samples revealed increased concentrations of met-enkephalin in three of the five patients, and increased concentrations of catecholamines in the four patients in whom they were determined. Conclusions: The results obtained in this study indicate that subarachnoid adrenal medullary transplantation may provide a unique and effective approach to the management of intractable chronic pain in humans.