Surgical approaches: postoperative care and complications “posterolateral–far lateral transcondylar approach to the ventral foramen magnum and upper cervical spinal canal”

Abstract

Lesions that affect the lower clivus, foramen magnum, the craniocervical junction, and the upper cervical spinal canal that are anterolateral and at times intradural require access ventral to the cerebellum and spinal cord. The posterolateral transcondylar approach provides such a route. In addition, posterior craniocervical stabilization can be accomplished at the same time. The author has reviewed the technique as well as the surgical results here. The posterolateral transcondylar approach to the craniocervical junction was utilized in children with schwannoma, meningioma, and chordoma affecting the cervicomedullary junction. Other entities such as neurenteric cysts and hemangioblastoma were also seen. Extradural tumors such as aneurysmal bone cysts of the atlas and the axis vertebrae as well as proatlas segmentation abnormalities and bone tumors were seen. The stability of the craniocervical junction was assessed preoperatively so that a fusion procedure could be accomplished at the same operative setting, if necessary. Preoperative evaluation of the lower cranial nerves was vital. The surgical procedure was accomplished in the prone position. The occipital bone removal was carried out up to the sigmoid sinus and toward the jugular bulb. Relocation of the vertebral artery was made at the atlas vertebra and thus provided posterolateral exposure into the posterior fossa and upper cervical spinal canal. Occipital condyle removal was limited to one-third of the medial occipital condyle. Twenty-five children underwent a posterolateral transcondylar approach. New lower cranial nerve dysfunction occurred in two and only one required a tracheostomy. This was seen in a child with clivus chordoma. A complete removal was accomplished in meningioma and schwannoma as well as in neurenteric cyst and hemangioblastoma. Clivus chordomas required more than one surgical procedure. The tumors of the bone were all treated with simultaneous fusion. The posterolateral transcondylar route is a versatile avenue to approach a variety of lesions ventrolateral to the brain stem and upper cervical cord. Exposure is quite satisfactory with minimal or no retraction of important neurovascular structures in the region. Modifications of this theme can be applied as the lesions require.