Selective intrathecal phenol block to improve activities of daily living in patients with spastic quadriplegia. A preliminary report

Intrathecal phenol: an old treatment revisited

PURPOSE

Severe bilateral leg spasticity can cause severe symptoms and reduced quality of life in affected individuals. It is often unresponsive to treatment. The objective of this study was to review the effectiveness of intrathecal phenol in the treatment of severe bilateral leg spasticity.

METHOD

A retrospective case notes review of patients treated with intrathecal phenol by a rehabilitation service was performed. A simple rating scale based on comments in the case notes was used to identify changes in spasticity and treatment goals.

RESULTS

Forty patients were identified as having been treated with intrathecal phenol over a 10-year period. All patients had improvements in their spasticity, 34 of which were rated as substantial or excellent. All patients (in whom the effect was documented), except one, had short-term improvement in the goals for treatment, 31 having substantial or excellent improvement. The effect was long lasting in many of the patients. Seven patients required repeat injections with similar outcomes. Seven patients experienced temporary side-effects.

CONCLUSION

Intrathecal phenol is a useful alternative in treating selected patients with chronic severe bilateral leg spasticity that is unresponsive to other treatments.

Nerve root degeneration and regeneration by intrathecal phenol in rats: a morphologic approach

Intrathecal injection of phenol (ITP) has been used to control intractable pain and spasticity. Direct caustic nerve damage has been postulated as the mechanism of analgesia. Sensation is commonly recovered, suggesting that a spontaneous regeneration process takes place. There is, however, a lack of mechanistic information on ITP therapy. To define morphologically the neurolysis and regeneration phenomena produced by ITP, anesthetized rats were subjected to laminectomy at L5; 5 microl of 22% phenol in saline solution or vehicle (control) was injected. Light and electron microscopy studies of nerve roots were performed at 2, 14, and 60 days after injection. Rats given ITP showed at the early stage a variable amount of roots with signs of infarction characterized by loss of axon-myelin units and thrombosis of intra-root vessels. At 14 days, abundance of macrophages removing debris, open vessels, and nerve sprouts was identified in damaged roots. At this time, non-myelinating glial fibrillary acidic protein-positive Schwann cells were observed in both damaged and apparently undamaged roots. At 60 days, abundance of 2',3'-cyclic nucleotide 3'-phosphodiesterase-positive Schwann cells myelinating newly formed axons was observed in damaged roots. Control rats did not show signs of neural or vascular pathology. Attempting to prevent thrombosis, another group of rats received heparin before ITP; these anti-coagulated rats developed radicular thrombosis, neurolysis, and hemorrhage. In conclusion, neurolysis produced by ITP is associated with acute ischemia (not prevented by heparin) and is followed by vascular, nerve, and myelin regeneration. Our results help understand the lack of efficacy of and some complications by ITP clinical therapy.