THE VA-CYBERWARE LOWER-LIMB PROSTHETICS-ORTHOTICS OPTICAL LASER DIGITIZER

Characterization of the residual limbs and limb segments of patients f or prosthesis and orthosis design has principally been a subjective pr ocess, highly dependent upon the skill, level of training, and experie nce of the prosthetist/orthotist involved. Even with the application o f computer-aided design (CAD) and computer-aided manufacturing (CAM) t echnologies in prosthetics and orthotics, residual limb/limb segment c haracterization has remained substantially subjective and dependent up on prosthetist/orthotist skill, training, and experience. To eliminate the variations and errors that frequently occur because of this depen dence, and to further quantify the patient measurement process, rehabi litation engineering researchers at the New York Department of Veteran s Affairs Medical Center developed an optical laser digitizer for quan titative characterization of patients' residual Limbs'/limb segments' spatial geometry and surface topography. The optical digitizer develop ed is described, and results of laboratory and clinical tests with the digitizer are presented. Examples showing the capability of the digit izer to accurately, rapidly, repeatably, and consistently capture the contours over the entire surfaces of the residual limbs of patients wi th below-knee (BK) and above-knee (AK) amputation, the lower limbs of orthotics patients, and the feet and ankles of pedorthics patients, ar e given. In addition, results of a comparative clinical study of optic al digitization and standard prosthetics CAD plaster wrap cast electro mechanical digitization of the residual limbs of subjects with BK and AK amputation are presented. The enhanced accuracy, repeatability, and consistency afforded by optical digitization are shown. Finally, area s for refinement of the optical digitizer's design, identified in the project's laboratory and clinical tests, are discussed.