Hypothenar hammer syndrome: A case of a late complication after surgery.

Hypothenar hammer syndrome is a rare condition secondary to ulnar artery damage in Guyon's canal, affecting mainly those exposed to repeated palm trauma. Surgery is discussed in cases of severe symptoms that are resistant to conservative treatment, and/or when anatomical lesions with high embolism potential are discovered during imaging exams. Resection of the pathological zone with revascularization by autologous vein graft is the best option. We report the case of a 60-year-old patient who had a recurrence of symptoms more than 10 years after this type of surgical treatment was performed. There was an aneurysmal thrombosed vein graft with extensive thrombus from the ulnar artery upstream to Guyon's canal to the superficial palmar arch. Finger revascularization was provided by the superficial branch of the radial artery and the presence of a collateral vascular supply. This late complication was responsible for compression of the ulnar nerve in Guyon's canal. A new surgery was performed to resect the thrombosed zone, including the vein graft, without vascular reconstruction due to the good vascularization of all the fingers, and to release the ulnar nerve at the wrist. The postoperative course was uneventful with the disappearance of pain and sensory-motor deficits. Good finger vascularization was confirmed by imaging at 3 months postoperative; nerve conduction was normal at 6 months on electroneuromyography.