Was Hippocrates a beginner at trepanning and where did he learn?

A critical reading of Hippocrates'On Wounds of the Head suggests the writer was a beginner at trepanning. He could not explain clearly, in the pathological terms used in his time, why routine early trepanning was beneficial. His technique was hesitant, suggesting he himself had never done the routine early trepanning he advocated, and he had not yet realised that his policy would be unacceptable to most Greek patients. It is suggested that he might have learnt trepanning on a brief trip to Marseilles, where the Gauls had already trepanned for 1500 years.