Transoral operations for craniospinal malformations.

The transoral approach to the lower third of the clivus and to the ventral aspect of the upper cervical spine is used in craniospinal malformations with or without dislocation as well as in basilar aneurysms, ventrally situated cranio-spinal tumours, fractures of the odontoid process, and in rheumatoid arthritis compressing the spinal cord. In consideration of the literature and ten personal cases the indications and techniques of the transoral approach in craniospinal malformations are discussed. According to our own experiences and those of other authors it is possible to expose the lower clivus and the cervical spine down to C2 by a midline incision of the pharyngeal wall using a mouth retractor and oral intubation. Splitting of the soft palate or resection of the hard palate are not necessary, a tracheotomy should be performed only in exceptional cases. In congenital craniospinal malformations without dislocation or instability causing a ventral compression of the spinal cord, for instance by the odontoid process, the transoral decompression is preferable to dorsal decompressing operations. In cases of pure instability without any space-occupying lesion the transoral and posterior approach are possible in order to perform a fusion. The last one seems more advantageous in these cases. In craniospinal malformations with dislocation causing a ventral and dorsal narrowing of the spinal canal, apart from the decompression a stabilization has to be achieved. In these usually complex malformations individual treatment is necessary. According to the rare cases in the literature and to our own experience a primary anterior decompression, followed by a most careful posterior stabilization seems to produce the most favourable results.