A 70-year-old man complained of color change on the right side of his little finger, which was injured while hitting a metal can repeatedly with a wrench for the 1st time, and presented to our hospital on the same day. His condition was diagnosed as atrial fibrillation and hypertension 14 years ago, for which he took the anticoagulant warfarin (3 mg/day) along with a β-blocker (2.5 mg/day) and an angiotensin-converting enzyme (ACE) inhibitor (2.5 mg/day) for 14 years. The patient had no history of smoking. The injury was on his right hand (the dominant side). The ischemic change in the skin was distal to the distal interphalangeal (DIP) joint of the little finger (-). He reported sensory disturbance and pain in the same region, and a feeling of coldness distal to the MP joint. The digital Allen test was negative. The range of motion (ROM) was normal. The manual muscle testing (MMT) of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) yielded a 5/5 score. The Semmes-Weinstein monofilament test (S-W test) score was 4.56 (normal: 1.65–2.83, diminished light touch: 3.22–3.61, diminished protective sensation: 3.84–4.31, loss of protective sensation: 4.56–6.65, and untestable: ≥6.65). X-ray findings were normal. Computed tomography (CT) images showed no fracture. Contrast-enhanced CT showed a superficial palmar arch from the radial and palmar metacarpal arteries. The ulnar artery was occluded at the bifurcation from the brachial artery ( and ). The radial digital artery of the little finger was interrupted at the proximal metacarpal bone ( and ). The superficial palmar arch, common palmar digital artery, and ulnar digital artery of the little finger were also not enhanced. Intravenous prostaglandin E1 (PGE1) administration slightly improved the skin color, and the disorder was considered to be reversible vasospasm, with no neuropraxia. We prescribed PGE1 tablets and instructed the patient to continue taking warfarin, β-blocker, and ACE inhibitor as before. He was also instructed to keep his finger warm using protective gloves and recommended to rest at home during the observation period. In addition, we prescribed acetaminophen for inflammation and pain relief. After 1 week, his symptoms did not improve. The patient presented with signs of ischemia restricted to the tip of his little finger, which did not correspond to the CT findings. As the signs of ischemia were restricted to the distal end, surgical intervention was necessary to confirm the viability of the blood vessels. Urgent adventitial dissection of the artery was performed. An axillary nerve block was performed under echo guidance. However, blood flow did not improve due to the vasodilatory effect of the block. Blood flow did not resume sufficiently despite adventitial dissection of both sides of the digital arteries at the DIP joint. Therefore, arterial occlusion was suspected to be caused by thrombus formation and not by spasm. Furthermore, extending the adventitial dissection to the proximal revealed extensively occluded ulnar digital artery (). Dissecting the MP joint revealed a bruise around the radial digital artery, which was adhering to the surrounding tissue. Proximal to the site, the artery had good pulsation (). However, blood flow did not recanalize with the adventitial dissection of the digital artery. Thrombi, occlusion, and a corkscrew appearance were observed in the area extending from the DIP joint to the MP joint on the ulnar side, which was different from the radial side (). Radial digital artery reconstruction was scheduled. We made a partial incision in the wall of the occluded artery. The thrombus in the arterial lumen was removed, and the incised arterial wall was subsequently sutured. However, blood flow did not recanalize. It was completely occluded in this region. Approximately 5 mm of the injured artery was resected, and a thrombus found distal to the arterial lumen was removed (). The normal artery was anastomosed. The digital artery recanalized thereafter (). The pain subsided immediately after surgery. A continuous infusion of heparin (8,000 units/day) and PGE1 was administered for 1 week. Cefazolin (2 g/day) was infused for 3 days after surgery. The color tone improved and stabilized (). Final ROM (flexion/extension) values were MP 85/5, PIP 80/-5, and DIP 70/-5 (). The S-W test score also normalized (1.65), and MMT results of the FDP and FDS were stable (5/5). The digital artery was examined using a color Doppler system (SONIMAGE MX1, Konica Minolta Inc., Tokyo, Japan; L11-3 MHz Linear probe, total scan depth of 20 mm). Echography revealed stable blood flow in the anastomosed artery on the radial side (). The blood flow was lower in the ulnar digital artery of the MP joint than in the radial side on the sagittal view (). The ulnar-side artery had a smaller diameter and less blood flow than the radial side on the coronal section at the DIP joint (). Contrast-enhanced CT re-evaluation of the artery 1 month after the surgery revealed persistent ulnar artery occlusion at the bifurcation of the brachial artery (, solid arrow). The proper palmar digital artery of ulnar side was occluded (, dashed arrow). Therefore, the occlusion was thought to have existed before this trauma. The radial side from radial artery was enhanced (, dashed arrow), and anastomosis was effective. The patient’s recovery was unremarkable, with no associated symptoms observed at the final follow-up visit one year after surgery. The levels of expertise of the surgeons involved with this article, according to Tang and Giddins [], were as follows: Author 1 (Level 4-Specialist, highly experienced); author 2 (Level 5-Expert); and author 3 (Level 5-Expert).