A new method of dorsal arthrodesis in patients with atlanto-axial instability of different etiology is described. In three patients solid laminar osteosynthesis C1/C2 was achieved by insertion of an autogenous cortico-cancellous bone graft into the interlaminar space and by a bilateral application of the lately developed metal clamp. The technical principles of the clamp guarantee a permanent pressure on the graft and a solid initial stability in the segment. Additional external fixation and immobilization of the patient are not necessary. Complications as known from other procedures of the atlanto-axial dorsal fusion will be prevented efficiently.