This is tooth that was removed post sinus augmentation years ago in the 14/15 region. With the tooth in place, the graft material had moved into the 16 region but did not cover the medial portion of it. A conventional internal sinus lift (osteotome and mallet) nor lateral window will work, the defect is in the palatal portion of the ostoetomy. Options:
1) place implant angled to the buccal
2) attempt lifting of sinus in palatal portion of osteotomy with CAS-kit or piezo instrument
3) attempt lifting of sinus with palatal osteotomy, then graft around implant

Decided on option 2. Osteotomy prepared to about 2.8mm, piezo tip with water coming from the tip utilize to lift sinus membrane. Thick membrane noted on scan. Collatape placed followed by allograft. Implant placed in the usual manner. Bone noted in palatal defect of post op scan but bone could have been placed more superiorly.