Local ectopic implantation for salvaging an amputated thumb: an anatomical study and a case report.

Relatively few cases of the ectopic implantation of an amputated thumb have been reported. The majority of ectopic sites are far from the original anatomic site, and anastomosis of the artery cannot be avoided in the secondary replantation surgery, which increases the failure rate. We conducted an anatomic study to investigate the possibility of performing local ectopic implantation of an amputated thumb at the wrist level such that an arterial pedicled thumb could be harvested in the secondary surgery. Thirty radial arteries were dissected from the point 3 cm proximal to the radial styloid to the point at which they passed over the radial styloid. Each branch with a diameter >0.8mm was selected. The mean number of branches was 3.2 > ± 1.37, and the mean diameter was 1.09 ± 0.83 mm. The mean diameter of the ulnar digital artery in the thumb was 1.08 ± 0.15 mm at the metacarpophalangeal joint level. Following anatomic research, an amputated thumb was ectopically implanted locally and replanted during a secondary operation without anastomosis of the artery. The amputated thumb survived, and its function was partially restored. In conclusion, the branches of the radial artery that have a similar diameter to the ulnar digital artery of the thumb can always be located at the wrist level. Local ectopic implantation is feasible and can help prevent the need for anastomosis of the artery during the secondary replantation surgery.