Medical and surgical devices, instruments, and methods for treatment of the spine and for nerve surveillance, guidance, and monitoring, namely, bone screws, fixation devices, spacing devices, alignment devices, insertion and extraction devices, prosthetic intervertebral discs, implants, implant materials, implant anchorages, biologics, and nerve surveillance systems comprising electrodes, sensors, monitors, cabling, and computer hardware and applications and operating software therefore; optical devices for use in surgical and medical targeting