A surgical instrument for treating a spine, comprising: a first member (14; 214; 314; 414) having an inner surface and an outer surface ; and a second member (16; 214; 314; 414) having an inner surface and an outer surface , the outer surfaces being engageable with tissue adjacent a spine that defines a longitudinal axis (X1), wherein the members (14, 16; 214; 314; 414) are connected with a handle having handles , wherein the handles are connected with the members (14, 16; 214; 314; 414), respectively, and wherein the outer surface of at least one of the members includes a projection being an end lip on an end of the at least one of the members and extending laterally therefrom, characterized in that the handles are pivotally connected at a pivot such that the first member (14; 214; 314; 414) is rotatable about the pivot and the second member (16; 214; 314; 414) is rotatable about the pivot from a closed configuration to an open configuration to space the tissue, wherein, in the closed configuration, the inner surfaces define a substantially oval cavity that defines a major axis (X2) and a minor axis (X3), and the end lip extends in a direction parallel to said major axis (X2), and wherein, in the closed configuration, the members (14, 16; 214; 314; 414) are disposable by the handle between a first position, in which the major axis (X2) is substantially aligned with the longitudinal axis (X1), when the outer surfaces are engaged with the tissue adjacent the spine, and a second position, in which the major axis (X2) will be rotated relative to the longitudinal axis (X1) to space psoas tissue, and in which the lip will be rotated under the psoas tissue. a first member (14; 214; 314; 414) having an inner surface and an outer surface ; and a second member (16; 214; 314; 414) having an inner surface and an outer surface , the outer surfaces being engageable with tissue adjacent a spine that defines a longitudinal axis (X1), wherein the members (14, 16; 214; 314; 414) are connected with a handle having handles , wherein the handles are connected with the members (14, 16; 214; 314; 414), respectively, and wherein the outer surface of at least one of the members includes a projection being an end lip on an end of the at least one of the members and extending laterally therefrom, characterized in that the handles are pivotally connected at a pivot such that the first member (14; 214; 314; 414) is rotatable about the pivot and the second member (16; 214; 314; 414) is rotatable about the pivot from a closed configuration to an open configuration to space the tissue, wherein, in the closed configuration, the inner surfaces define a substantially oval cavity that defines a major axis (X2) and a minor axis (X3), and the end lip extends in a direction parallel to said major axis (X2), and wherein, in the closed configuration, the members (14, 16; 214; 314; 414) are disposable by the handle between a first position, in which the major axis (X2) is substantially aligned with the longitudinal axis (X1), when the outer surfaces are engaged with the tissue adjacent the spine, and a second position, in which the major axis (X2) will be rotated relative to the longitudinal axis (X1) to space psoas tissue, and in which the lip will be rotated under the psoas tissue. <EOS>