The risk of anaphylaxis in candidates for chemonucleolysis for herniated lumbar discs is approximately 1%. An investigation was designed to eliminate or reduce the incidence of chymopapain anaphylaxis. The procedure was to restrict chemonucleolysis to patients who are prick test-negative to chymopapain at a concentration of 10 mg/ml. The authors skin-tested 292 chemonucleolysis candidates; five were positive and 287 were negative. None of the positive patients were injected with chymopapain. There were no instances of unequivocal chymopapain anaphylaxis in the skin test-negative group. This 0% incidence of anaphylaxis in skin test-negative patients was compared with a population estimate of 1%, based on historical data. The resulting value of p = 0.08 value fell short of the conventional level of significance of 0.05. The p value will reach 0.05 when the series of skin test-negative patients without anaphylaxis reaches 360. It is important that this information is readily available to physicians concerned about anaphylactic reactions to chymopapain.
From the Section of Allergy-Immunology, Department of Medicine and Department of Orthopedic Surgery, Northwestern University Medical School, Chicago, Illinois.
* Section of Allergy-Immunology, Department of Medicine, Northwestern University Medical School, Chicago, Illinois.
** Department of Orthopedic Surgery, Northwestern University Medical School, Chicago, Illinois.
† University of Cincinnati Medical Center, Cincinnati, Ohio.
‡ McMaster University, Ontario, Canada.
§Kaiser-Permanente Medical Center, San Diego, California.
∥ Hope College, Holland, Michigan.
¶ University of Pennsylvania, Philadelphia, Pennsylvania.