Instruments are provided for delivering and installing a multi-section spinal implant in-situ one section at a time by sequential deployment and assembling of the multi-section spinal implant sections into an intervertebral space. An advancement mechanism provides controlled deployment of individual implant sections from the instrument. Each instrument accepts a plurality of implant sections that are stacked on a deployment rod. Activation of the advancement mechanism advances a pusher against a rearward implant section of the implant section stack. This, in turn, advances all or some of the implant sections such that the forward most implant section exits the instrument. As the advancement mechanism is further activated, additional implant sections are deployed from the instrument. In this manner, a multi-section spinal implant of any number of implant sections may be delivered and assembled in situ. In one form, the advancement mechanism comprises an indexing mechanism. In another form, the advancement mechanism comprises a ratchet device provided on and between a trigger and an advancement tube.
