Ratcheted spinal device

A spinal device, comprising:

• an implantable housing;
• an implantable length member disposed in the housing, the length member having a length that protrudes out of the housing a variable amount, the length member and the housing together comprising a mechanism configured to allow progressive increases in the amount the length member protrudes out of the housing and to automatically prevent decreases in the amount the length member protrudes out of the housing;
• an implantable first polyaxial-joint attachment socket disposed in the housing and configured to hold a first pedicle screw, configured to enable polyaxial rotation of the first pedicle screw, and configured to enable pivoting movement of the first pedicle screw about more than one pivoting axis;
• an implantable second polyaxial-joint attachment socket held outside of the housing by the length member and configured to hold a second pedicle screw, configured to enable polyaxial rotation of the second pedicle screw, and configured to enable pivoting movement of the second pedicle screw about more than one pivoting axis;
• and
• a wedge having a substantially triangular cross-section located at least partly within the housing,
• wherein the length member does not include ratchet teeth arranged to move outside of the housing in conjunction with changes in the amount the length member protrudes out of the housing, and
• wherein the housing, the wedge, and the length member are arranged to cooperate to automatically prevent the decreases in the amount the length member protrudes out of the housing.