ADA4254 EPAD Connection Best Practice

In the ADA4254 datasheet, when using the 28-Lead LFCSP (ADA4254ACPZ) it mentions to 'CONNECT THE EXPOSED PAD (EPAD) TO VSSH'.  However, it does not give any additional layout considerations or best practice considerations about what type of thermal copper pad needs to be included in the layout.  Since this opamp only draws a mere 22mW I am thinking that it would not require a large thermal copper area under the EPAD.  Our current layout simply has a copper pad for the EPAD to solder down too, but no thermal pad of VSSH (-12.5V) on the opposite side. An image of our layout is below.  Are there any thermal concerns or other concerns with connecting the EPAD in this manner? Thanks.

edit: I should also note that I have not found any reference designs for the ADA4254ACPZ (LFCSP package).  Only reference designs with the TSSOP package.