For the left side, we decided to access the sinus using a lateral window as the area of deficient bone was much larger in size and more complex in shape. We also decided to approach this area from the palate, as the defect was closer to the palate and required much less bone removal as a buccal approach. Most importantly, we were already familiar with the anatomical structures on the lower medial wall of the sinus in the access area as we visualized this area during the first graft surgery and CT scans showed no signs of larger intraosseous vasculature in the area. Given this specific case, and knowledge of the vascular anatomy of the maxillary sinus in the surgical area (Fig. 8, based on CT scans of this patient and Bailey et al.’s work [22]), we felt that our approach would not invade the zone of risk for bleeding complications. We performed the surgery similar to a conventional lateral window sinus augmentation surgery using piezosurgery and a buccal approach, except from the palatal side of the alveolar ridge and staying clear of the greater palatine neurovascular bundle (Fig. 9). Here, we created a mucoperiosteal flap with vertical release at no. 13 (Fig. 10a, b). Using a piezotome and piezosurgery inserts (Piezotome 2, Acteon North America, Mount Laurel, NJ, USA), we created a rectangular window over the bony defect, avoiding any vascular structures (Fig. 10c). Using piezosurgery inserts and hydraulic pressure (IntraLift Kit, Acteon North America, Mount Laurel, NJ, USA), we carefully removed the Schneiderian membrane from the finger-like defect (Fig. 10d–f). We then placed a root-form 4.7 mm × 10 mm implant (Fig. 10f; Tapered Screw Vent TSWB10, Zimmer, Carlsbad, CA, USA) according to standard protocol and achieved good primary stability in excess of 30 Ncm. We placed a strip of resorbable collagen tape over any exposed Schneiderian membrane, grafted the site with 1.2 ml cortical particulate allograft (LifeNet Health, Virginia Beach, WA, USA) and placed a resorbable collagen membrane (ConFORM, ACE Surgical Supply, Brockton, MA, USA) over the palatal access window (Fig. 10g–i). We then covered the implant and graft with the palatal flap and sutured it with PTFE 3-0 (Cytoplast, Osteogenics Biomedical, Lubbock, TX, USA) continuous and horizontal mattress sutures (Fig. 10j). A postoperative radiograph showed good containment of the graft material (Fig. 10k).