Spinal cord stimulation in the treatment of failed back surgery syndrome

A significant number of patients undergoing lumbar spine surgery do not obtain pain relief. Such patients with chronic low back or lower extremity pain may be difficult to treat. A frequent component of therapy is the use of spinal cord stimulation to help control pain. With careful patient selection, many patients can achieve reasonable levels of pain relief. We review recent clinical reports, including prospective and randomized studies, that demonstrate up to three quarters of patients implanted with a spinal cord stimulator for the treatment of failed back surgery syndrome may benefit from its use. This technology must not be indiscriminately applied. Careful patient selection and a period of trial stimulation are vital to the successful use of spinal cord stimulation as treatment for chronic pain.     

Synthesis and in vitro LTD4 antagonist activity of bicyclic and monocyclic cyclopentylurethane and cyclopentylacetamide N-arylsulfonyl amides

The dissociation constants (KB) at the LTD4 receptor on guinea pig trachea of a series of monocyclic and bicyclic cyclopentylurethane and cyclopentylacetamide N-arylsulfonyl amides have been measured. The KB was found to be remarkably tolerant of changes in the electronic constitution and lipophilicity of the bicyclic ring system (template). Thus, N-[4[[6-[[(cyclopentyloxy)carbonyl]amino]benzimidazol-1- yl]methyl]-3-methoxybenzoyl]benzenesulfonamide (11a) and N-[4-[[5-[[(cyclopentyloxy)carbonyl]amino]benzo[b]thien-3- yl]methyl]-3-methoxybenzoyl]benzene-sulfonamide (25a) had closely similar affinities (pKB, 9.20 and 9.31, respectively; LTE4 as agonist). It has been shown that the hetero-ring of the template need not be aromatic in order to achieve high affinity, since indoline 31 and 2,3-dihydrobenz-1,4-oxazines 37a-c had pKBs greater than 9. Further, it has been shown that an o-aminophenone (see 42 and Figure 3) can function as a template; the template in 42 [see iii] is bicyclic by virtue of the presence of an intramolecular hydrogen bond. In contrast, when the template is a phenyl ring (48), receptor affinity is markedly reduced. These findings support the notion that central bicyclic ring system in this family of peptidoleukotriene antagonists is a molecular feature which helps to preorganize the acylamino and acidic chains and thereby facilitate the molecular recognition event.