In the surgery, scientists injected genetically engineered bone marrow stem cells into the man's brain in the hope of assisting recovery.
Led by Professor Thomas Brinker, of the International Neuroscience Institute in Hanover, the trial was designed to assess the safety of the new technique only, and not to monitor its effectiveness.
And the therapy under trial is called CellBeads, which uses mesenchymal stem cells, which is a type of cells found in bone marrow capable of forming fat and muscle cells.
Mesenchymal stem cells are genetically engineered to produce a protein that inhibits cell death, which could limit brain damage after a stroke.
The donated stem cells are encapsulated in special beads to protect them from the patient's immune system, which would otherwise destroy them as foreign tissue.
In this case, the stem cells act as a powerful tool to deliver the protein - and not as replacement tissue.
In the end, the trial will involve 20 patients. And still, Brinker claimed that the early indications showed promise.
"We see a path of recovery as good as this only in the minority of patients, so it is an encouraging start. It is most important that we found [that there were] definitively no side-effects from the treatment," Times Online quoted him as saying.