Assuming similar proportions even a study of 5000 patients would not have shown a significant difference between the two groups.
A study of 60 patients who have had the procedure is now under way, and the results are promising.
The report was based on a study of 374 patients admitted to a hospital in 1997 and 1998.
In a study of 524 patients, he had found that half the children died despite maximum treatment.
He cited a study of 186 patients with acute back pain.
Subsequently, the relationship was confirmed in a study of 4,000 patients.
Longer studies of more patients are still needed, however.
His advice was based on studies of nearly 8,000 patients.
In the study of 50 patients, only 50% wished to proceed to surgery.
In 2003 he published a study of 38 patients who were given this treatment.