Our design and implementation of a novel 3D printed cutting guide to improve osteotomy precision. Radial donor site offers only a limited amount of bone stock, before the structural integrity of the distal radius is compromised. Pathological fracture rates have been reported in the literature to be as high as 50% without prophylactic plating of the radius. We hypothesised that the use of cutting guides and virtual surgical planning could greatly improve the precision in the radial osteotomies and therefore theoretically decrease the risk of stress risers and pathological radius fracture after harvesting this flap. Due to the peri-osteal blood supply of the bone portion of the flap and the need to maintain the integrity of the septum and cuff of pronator quadratus between the pedicle and the volar radial cortex of the distal radius, traditional positive cutting guides would not be able to be coapted to the desired bone. Therefore we designed a negative cutting guide where by the guide coapts in two interlocking pieces to the radius on the outer perimeter of the proposed bone cuts and therefore can fit onto the radius accurately without soft tissue interposition. This paper showcase our virtual surgical planning work flow for a midfacial microsurgical reconstruction case in which we used a custom 3D printed cutting guide / osteotomy guide to harvest vascularised radius bone.