Page 197 - Handbook of Biomechatronics

194 Georgios A. Bertos and Evangelos G. Papadopoulos

According to Beasley, this tendon exteriorization principle can be
applied in a variety of arrangements and the undamaged muscles retain
excellent power.
The use of tendon grafts has the advantage of preserving all the force and
excursion that the muscle is capable of also of and maintains the Golgi ten-
don organs and their resultant contributions to the proprioceptive feedback
of the muscle. In those instances, where a tendon is not available, the use of
artificial tendons attached to the residual muscle and then brought outside
the limb in loops has also been suggested.
Besides the many advantages of tendon exteriorization procedure over
tunnel cineplasty there is one disadvantage: with the tendon exteriorization
procedure the force capability is of the order of 1–1.5lb.; thus externally
powered prostheses must be used. Fig. 11A shows a schematic of the final
result of a tendon exteriorization procedure, and Fig. 11B shows a specially
modified Otto-Bock hand driven by these exteriorized tendons (Childress
et al., 1993).
Since both procedures: tunnel cineplasty and exteriorized tendons are
surgical procedures, it is imperative that the surgeon, prosthetist, amputee,

Fig. 11 (A) Schematic representation of a forearm tendon exteriorization cineplasty.
(B) Modified Otto-Bock hand to be driven by exteriorized tendons built at Northwestern
University Prosthetics Research Laboratory. ((B) Photographs courtesy of Northwestern
University Prosthetics Research Laboratory.)