2022 Volume 22 Issue 1 Pages 41-50
This study examined the usefulness of the lasso procedure, a reconstructive operation that uses the flexor digitorum superficialis muscle (FDS) as the donor muscle, for treating the claw hand deformation caused by paralysis of the intrinsic muscles. The subjects were 10 healthy adults, electromyograms for which were derived using wire electrodes attached to the FDS, with the ulnar flexor digitorum profundus (FDP), 4th dorsal interosseous muscle, and 2nd palmar interosseous muscle used as comparisons. For the exercise tasks used to derive the electromyography (EMG), the subjects completed a metacarpophalangeal (MP) joint exercise task with the proximal interphalangeal (PIP) joint held in the extended position and two gripping tasks. The FDS showed high activity during MP joint flexion and adduction (p < 0.001). In the cylindrical grasp task, the FDP was active and the intrinsic muscle was dominant. In the intrinsic muscle grasp task, the FDS showed high activity and the interosseous muscle was active. Considering that the lasso procedure can reconstruct the intrinsic muscle, the FDS is active in synchronization with the intrinsic muscles, especially the palmar interosseous muscle. Therefore, the lasso procedure using the FDS requires less training for postoperative functional transformation and is a valid reconstruction method for treating the claw hand deformation.
