Modified pediculo facetectomy in ventral compression of the thoracic spinal cord

Abstract

As compared to the cervical or lumbal region thee spinal canal is substantially narrower at the thoracic segment. Because of the narrower subarachnoidal space small masses may already compress the spinal cord. Ventrallocalization of lesions in the thoracic spinal canal and anterior compression ofthe spinal cord/e.g. intervertebral disc herniation, spondylosis, osteochondroma, meningioma/ involve technical decompression difficulties. In addition to the mentioned rare localizations other neoplasms may occur, such as has been observed in one of our case, e.g. epidermoid tumor (cholesteatoma) . In spite of intervertebral disc herniation, being a most common disease, its thoracic localization inducing neurological symptoms is scarce and amounts appr. 0,25-0,75 per cent. Latter are present at 75% between Th-8 and Th-12, in majority at Th-ll.(4) According to Carson (8) thoracic intervectebral disc herniation occurs one/l million inhabitants yeatly. Osteochondroma is a calcifying tumour, which originates from the intervertebral synchondrosis. It is localized anterior to the spinal cord and is of extremely low incidence. Meningioma is a frequent form of extramedullary intraspinal tumor. It amounts to appr. 25 % of intradural spinal tumours and represent about 17 % of all CNS meningiomas. As to its localization it will be found mostly in the dorsal or lateral region in the spinal canal. Ventrallocalization with an invagination into the cord IS rareo Intervertebral disk herniation requires a more detailed discussion and also has been the goal of present paper. In a survey Perot and Munro (29) compiled 91 thoracic disc operations from the international literature, whilst Arce and Dohrman (4) reported in 1985 already on 280 operations. Altough these data support its rare occurrence, mis -or nondiagnosed cases and those established later on neurosurgical examination and treatment for radiating /e.g. multiple sclerosis, neurosis, cardiac-, pulmonary-or abdominal diseases/ have to be taken into consideration, too. Prior to the seventies decompression was performed mainly by larninectomy, which yielded poor results. Arseni and Hash (5) reported on a 60 per cent unsuccesss or even deterioration. In 50 per cent ofLogue's patient (23) postoperative improvement occurred. Tovi and Strang(34) reported on postlarninectomic deterioration in 30% ofthe patients. Obviously, the number of non-reported cases, due to the unfavourable results, should not be neglected. Animal experiments have been carried out to clear whether laminectomy, the so far used only method, was in fact inadequate. Experimental results of Doppman and Girton, (13) as well as of Bennett and McCallum (6) unambigously confirmed laminectomy did not meet requirements of the decompression of anterior spinal cord compression. New tecniques had to be sought for the atraumatic, safe removal of ventral lesions of the thoracical spinal cord. The aim of present study was to report on our recent results with pediculo-facetectomy /arthrotomy/ combined with laminectomy.