An improved apparatus is provided to allow for an adjustable length tether for use in the spine and other parts of the body. The tether comprises an artificial strand with an eyelet formed in one end, the other end being looped through the eyelet. The other end is then secured with respect to the eyelet by a crimp, the excess length being cut off after the length of the tether has been given an appropriate tension. Alternatively, the eyelet end may be formed around a grommet. The crimp may be separate from the grommet or a part of the grommet. The mechanism by which the length is adjusted in some cases will take advantage of the shape memory properties of alloys such as nickel-titanium.