1. The central action of botulinum toxin A (BTA) on the cholinergic transmission at Renshaw cells (RCs) and on the RC-induced inhibition of Ia inhibitory interneurones (IaINs) was studied in anaesthetized cats. BTA was administered by application directly into the spinal cord, injection into a ventral root (L7) and/or injection into the triceps surae (GS) muscle. 2. A direct application of BTA into the spinal cord led to a decrease of the early and the late response of RCs. 3. When the neurotoxin was injected into the GS muscle, the RC activity remained unaffected during the test period (33-46 h after application). 4. No effect appeared up to 10 h after an injection into the ventral root L7. 5. The RC-induced inhibition on IaINs, when tested in animals with local botulismus, remained intact during the test period. 6. From the present results it is suggested that on the spinal level the central action of botulinum toxin predominantly passes on the motoneurones.

The object of this investigation was to provide a statistical interpretation of macroscopic anatomic findings in the cranial cervical region, which is very rich in variation. In this way rare nervous and vascular variations could be related statistically. The first cervical posterior root demonstrated the most striking variations, which, according to anlage and connection with the accessory nerve, was divided into four anlage types of formation. In this way it was shown that in only 23% of the cases, no posterior C-1 root had been formed. It was further demonstrable that in at least part of the cases the accessory nerve was sensibly mixed with the first posterior root. Furthermore, nervous structures and peculiarities in the vessels were investigated. Special courses taken by the posterior inferior cerebellar artery, in addition to those already known, were statistically interpreted. Nervous as well as vascular contact and courses were analyzed, especially in relation to their topography to the accessory nerve, in order to provide clinicians with possibilities for explanations of irritations or compressions of this cranial nerve.

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.

For treatment of spasmodic torticollis (s.T.) microsurgical decompression of the intraspinal-intracranial portion of the accessory nerve (a.N.) has been performed in 11 patients with proved neurogenic lesions of the accessory nerve-dependent muscles. Neurogenic lesions were discovered by meticulous electromyographic (EMG) examination in 26 out of 32 patients with s.T. Based on the EMG findings and a.N. roots were exposed, mostly bilaterally. During operation we found in each case tight adhesions to adjacent structures, in particular the vertebral artery (v.A.), the posterior inferior cerebellar artery (PICA), and spinal arteries. Moreover, various nerve anastomoses were found between the upper dorsal cervical roots and the spinal a.N. roots. After neurovascular lysis and dissection of anastomoses, to C 1 in particular, the a.N. was protected with teflon-foam (Prosthex). Immediately after surgery torticollis had improved in all but one case. Further improvement was achieved by exercises. These first favourable results, and the fact that nerve decompression is less destructive that other surgical procedures in treatment of s.T., make us feel justified in recommending this procedure further to patients suffering from s.T. with proved neurogenic lesions.