Disclosed is an assembly and method for implant installation between adjacent vertebral bodies of a patient. The implant has a support body and a rotatable insert therein and the support body is curved for installation between adjacent vertebral bodies transforaminally. An installation instrument is also disclosed for removable attachment to implant and engagement with the rotatable insert to selectively permit rotation between the insert and the support body. The installation instrument extends along a longitudinal tool axis and when the installation instrument is in a first position the insert is rotationally fixed with respect to the support body and when the installation instrument is in a second position the support body may rotate with respect to the insert.