Maher (1951) has used a similar approach to eliminate the function of the posterior roots by injecting phenol dissolved in glycerine, or silver nitrate in phenol and glycerine. Whereas Dogliotti positions his patients for injection so that the roots to be eliminated are above the site of injection, since alcohol is lighter than cerebrospinal fluid (ascending intrathecal method), Maher does quite the opposite, since his solutions are of higher specific gravity than spinal fluid (descending intrathecal method). The latter injects 1 millilitre of a 7.5% solution of phenol. Present reports of the effect of this method are promising, but are still too few for a final judgement. Theoretically, this latter procedure may be used in the same way as the Dogliotti procedure.
A. S. Brown (1958) has followed in the same path by injecting a solution of carbolic acid in myodil (7.5 %) or in glycerine (5%) for the treatment of intolerable pain, primarily accompanying malignant tumours, in the region of the inferior half of the spine. This is also a solution heavier than spinal fluid, and is injected in a reclining position on the affected side. 2 ml are injected at once. The results thus far, after 21 months of observation, are promising. There are no unpleasant side-effects. The question still remains as to whether the long-term effects will also be good. If this should be prove true, it would still not be of great significance, since it is a procedure to be used in case of malignant, inoperable neoplasm.
With infiltration of the intervertebral connective tissue, Kjellgren (1948) found, on investigating the nerve supply to various parts of the body, that stimulation in the intervertebral spaces produces a similar pain as stimulation of the back muscles. Since it has been shown that these intervertebral structures are sharply localised, it occurred to us that this method might be reversed, that is, inhibit these pains by interspinal infiltration with procaine. We have attempted this on five occasions, with clear but temporary success, and consider the method worthy of further investigation. Three months after I started these experiments, I discovered that Leriche tried the same thing in one case of severe painful inflammation of the gastro-intestinal tract.