You’d better ask your surgeon. As long as I know, three-pieces osteotomy is generally needed when posteror expansion is needed without expansion of anterior segment (Please refer to the figures below). But, I am telling you again that surgical expansion is the least stable surgical modality and you have to avoid surgical expansion if possible.
From Dr. Sug-joon Ahn :
You’d better ask your surgeon. As long as I know, three-pieces osteotomy is generally needed when posteror expansion is needed without expansion of anterior segment (Please refer to the figures below). But, I am telling you again that surgical expansion is the least stable surgical modality and you have to avoid surgical expansion if possible.