Sclerotherapy for Baker's Cyst.

Centeno and coworkers (Pain Physician 2008: 11: 257-262) brought to light a very important subject (1). Historically, installation of irritating substances into a pathologic, fluid filled cavity has been known since Aurelius Cornelius Celsus (25 B.C.– 50 A.D.) described the injection of saltpeter (potassium nitrate), to cure hydrocele (2,3). Contemporary work with sodium morrhuate (SM) began in 1930 after Higgins and Kittel (4) wrote an article about therapeutic applications of this agent. A year later in 1931 Poritt (5) described the treatment of chronic olecranon and pre-patellar bursitis. He drained the fluid from the sac and injected 5% of SM. In persistent cases, he injected a 5% phenol solution. Subsequently, in 1933 Biegeleisen (6) published clinical and experimental research of SM in the United States. In 1936 he coined the term Sclerotherapy as a name for the injection clinic at the Stuyvesant Polyclinic in New York City, and very soon this term was adopted in the U.S. as well as abroad. Among the many applications for SM, he used it for bursitis in 5% strength, approximately 1 mL. for each 4 – 5 mL. of drained fluid. For ganglion cysts he preferred stronger solutions. He also introduced provocative sclerotherapy in chronic cases of “dry” bursitis injecting them with 1.25% or 2.5% of SM, converting them into an acute, fluid filled phase and then treated them as an acute stage. There is a plethora of literature on experimental and clinical histologic findings on various sclerosing solutions in the treatment of varicose veins, hernias, and synovial joints but none describe the post-injection findings in a cyst or a ganglion. There is however a case report from Ewell (7) describing intra-operative and histologic findings one month after 3 injections with quinine hydrochloride and urethane for hydrocele (this solution is allegedly less painful upon injection than SM. A small amount