A trial implant assembly (20; 120; 220; 320; 420; 520; 620; 720; 820; 920) comprising: a trial implant (22; 122; 222; 322; 422; 522; 622; 722; 822; 922) configured to be inserted into an intervertebral space defined by a superior vertebral body and an inferior vertebral body, the trial implant including: a trial base (34; 134; 234; 334; 434; 534; 634; 734; 834; 934) including an engagement member (32; 132; 232; 332; 432; 532; 632; 732; 832; 932) configured to couple the trial implant to a shaft (24; 124; 224; 324; 424; 524; 624; 724; 824; 924); and a trial head (36; 136; 236; 336; 436; 536; 636; 736; 836; 936) connected to the trial base and distally spaced from the trial base, the trial head defining a superior endplate (50; 150; 250; 350; 450; 550; 650; 750; 850; 950) having an upper surface and a lower surface (55; 155; 255; 355; 455; 555; 655; 755; 855; 955), and an inferior endplate (52; 152; 252; 352; 452; 552; 652; 752; 852; 952) having an upper surface (57; 157; 257; 357; 457; 557; 657; 757; 857; 957) and a lower surface, the upper surface of the superior endplate and the lower surface of the inferior endplate configured to face the superior vertebral body and the inferior vertebral body, respectively, characterized in that the trial head (36; 136; 236; 336; 436; 536; 636; 736; 836; 936) further defines at least one visualization window (60; 160; 260; 346; 446; 860; 960) extending distally there-through between the superior and inferior endplates (50, 52; 150, 152; 250, 252; 350, 352; 450, 452; 550, 552; 650, 652; 750, 752; 850, 852; 950, 952), wherein the visualization window (60; 160; 260; 346; 446; 860; 960) is at least partially defined by the lower surface (55; 155; 255; 355; 455; 555; 655; 755; 855; 955) of the superior endplate (50; 150; 250; 350; 450; 550; 650; 750; 850; 950) and the upper surface (57; 157; 257; 357; 457; 557; 657; 757; 857; 957) of the inferior endplate (52; 152; 252; 352; 452; 552; 652; 752; 852; 952). a trial implant (22; 122; 222; 322; 422; 522; 622; 722; 822; 922) configured to be inserted into an intervertebral space defined by a superior vertebral body and an inferior vertebral body, the trial implant including: a trial base (34; 134; 234; 334; 434; 534; 634; 734; 834; 934) including an engagement member (32; 132; 232; 332; 432; 532; 632; 732; 832; 932) configured to couple the trial implant to a shaft (24; 124; 224; 324; 424; 524; 624; 724; 824; 924); and a trial head (36; 136; 236; 336; 436; 536; 636; 736; 836; 936) connected to the trial base and distally spaced from the trial base, the trial head defining a superior endplate (50; 150; 250; 350; 450; 550; 650; 750; 850; 950) having an upper surface and a lower surface (55; 155; 255; 355; 455; 555; 655; 755; 855; 955), and an inferior endplate (52; 152; 252; 352; 452; 552; 652; 752; 852; 952) having an upper surface (57; 157; 257; 357; 457; 557; 657; 757; 857; 957) and a lower surface, the upper surface of the superior endplate and the lower surface of the inferior endplate configured to face the superior vertebral body and the inferior vertebral body, respectively, a trial base (34; 134; 234; 334; 434; 534; 634; 734; 834; 934) including an engagement member (32; 132; 232; 332; 432; 532; 632; 732; 832; 932) configured to couple the trial implant to a shaft (24; 124; 224; 324; 424; 524; 624; 724; 824; 924); and a trial head (36; 136; 236; 336; 436; 536; 636; 736; 836; 936) connected to the trial base and distally spaced from the trial base, the trial head defining a superior endplate (50; 150; 250; 350; 450; 550; 650; 750; 850; 950) having an upper surface and a lower surface (55; 155; 255; 355; 455; 555; 655; 755; 855; 955), and an inferior endplate (52; 152; 252; 352; 452; 552; 652; 752; 852; 952) having an upper surface (57; 157; 257; 357; 457; 557; 657; 757; 857; 957) and a lower surface, the upper surface of the superior endplate and the lower surface of the inferior endplate configured to face the superior vertebral body and the inferior vertebral body, respectively, characterized in that the trial head (36; 136; 236; 336; 436; 536; 636; 736; 836; 936) further defines at least one visualization window (60; 160; 260; 346; 446; 860; 960) extending distally there-through between the superior and inferior endplates (50, 52; 150, 152; 250, 252; 350, 352; 450, 452; 550, 552; 650, 652; 750, 752; 850, 852; 950, 952), wherein the visualization window (60; 160; 260; 346; 446; 860; 960) is at least partially defined by the lower surface (55; 155; 255; 355; 455; 555; 655; 755; 855; 955) of the superior endplate (50; 150; 250; 350; 450; 550; 650; 750; 850; 950) and the upper surface (57; 157; 257; 357; 457; 557; 657; 757; 857; 957) of the inferior endplate (52; 152; 252; 352; 452; 552; 652; 752; 852; 952).