Is it ethical/legal to withhold information in clinical publications?

Say, you are reporting a cohort of patients who underwent a specific surgical procedure. There are many steps in the process that pretty much everyone in the field follows. You, however, was the first to do that surgery using laparoscopy. Apart from that, the rest is routine. However, in step,say 8, instead of infusing liquid X you used Y instead. There is no harm done using X except that the patients would probably have worse outcomes, but still better than conventional. People would not... Is it ethical/legal to withhold information in clinical publications?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums