In 1981 we reported about a new surgical procedure for the treatment of spasmodic torticollis (ST). 33 patients, who failed to respond to the available conservative treatment, underwent a bilateral microsurgical lysis (BML) of the spinal accessory nerve roots (SRAN). Anastomoses between SRAN and the dorsal roots of the first and second cervical nerve (DRC 1/DRC 2) were cut. DRC 1 and sometimes DRC 2 were divided bilaterally. Moreover, SRAN was freed of all adhesions and vascular contacts. Up to 60 months after surgery we have excellent results in 5(5), good results in 10(7) and improved symptoms in 12(8) patients. In 3(7) patients symptoms were unchanged, 2(1) patients deteriorated (patients self assessment is given in brackets). One patient died during hospitalisation. Comparing torticollis symptoms and the post-operative outcome it can be shown that patients with horizontal ST have the best results (21 out of 22). Bad results were obtained in patients with combined torticollis symptoms such as retrocollis, antecollis and the rotatory/horizontal type (5 out of 9). These results support the hypothesis of a peripheral factor in the aetiology of horizontal ST. It is assumed that a unilateral disturbance of proprioceptive afferents for head control, which reach the CNS via anastomosis between DRC 1/DRC 2 and SRAN (in 94% of the cases) could be involved. This hypothesis is discussed with special regard to different anatomical findings in patients with ST and those revealed in a study on human cadavers without this disease.