An implant device (100; 300; 400; 500; 900; 1000; 1200; 1300; 1400; 1500) for implantation between adjacent vertebrae, the implant device comprising: an implant body (102; 302; 402; 502; 902; 1002; 1202; 1302; 1402; 1502); a first member (104; 304; 404; 504; 904; 1004; 1204; 1304; 1404; 1504) of the implant body configured for engaging a vertebra; a second member (106; 306; 406; 506; 906; 1006; 1206; 1306; 1406; 1506) of the implant body configured for engaging a vertebra; and an adjustable connection (126; 326; 426; 526; 928; 1040; 1226; 1326) between the first and second members, with the implant body being configured to be shifted between a compact orientation, with the first member engaged with the second member along predetermined portions thereof, and an extended orientation, with the predetermined portions of the first and second members shifted away from each other, wherein the adjustable connection is a pivot connection, and wherein the first member has a unitary, one-piece construction with a generally U-shaped configuration that comprises a first seat portion (112; 312; 412; 512; 912; 1016; 1212; 1312; 1412; 1512) with a first arm (114; 314; 514; 914; 1018; 1214; 1314;1414; 1514) and a second arm (116; 316; 416; 516; 916; 1020; 1022; 1216; 1316; 1416; 1516) extending from the first seat portion, and the second member has a unitary, one-piece construction with a generally U-shaped configuration that comprises a second seat portion (118; 318; 418; 518; 922; 1024; 1218; 1318; 1418; 1518) with a third arm (120; 320; 420; 520; 924; 1026; 1220; 1320; 1420; 1520) and a fourth arm (122; 322; 422; 522; 926; 1028; 1030; 1222; 1322; 1422; 1522) extending from the second seat portion. an implant body (102; 302; 402; 502; 902; 1002; 1202; 1302; 1402; 1502); a first member (104; 304; 404; 504; 904; 1004; 1204; 1304; 1404; 1504) of the implant body configured for engaging a vertebra; a second member (106; 306; 406; 506; 906; 1006; 1206; 1306; 1406; 1506) of the implant body configured for engaging a vertebra; and an adjustable connection (126; 326; 426; 526; 928; 1040; 1226; 1326) between the first and second members, with the implant body being configured to be shifted between a compact orientation, with the first member engaged with the second member along predetermined portions thereof, and an extended orientation, with the predetermined portions of the first and second members shifted away from each other, wherein the adjustable connection is a pivot connection, and wherein the first member has a unitary, one-piece construction with a generally U-shaped configuration that comprises a first seat portion (112; 312; 412; 512; 912; 1016; 1212; 1312; 1412; 1512) with a first arm (114; 314; 514; 914; 1018; 1214; 1314;1414; 1514) and a second arm (116; 316; 416; 516; 916; 1020; 1022; 1216; 1316; 1416; 1516) extending from the first seat portion, and the second member has a unitary, one-piece construction with a generally U-shaped configuration that comprises a second seat portion (118; 318; 418; 518; 922; 1024; 1218; 1318; 1418; 1518) with a third arm (120; 320; 420; 520; 924; 1026; 1220; 1320; 1420; 1520) and a fourth arm (122; 322; 422; 522; 926; 1028; 1030; 1222; 1322; 1422; 1522) extending from the second seat portion.