An operation for radical resection of a tumour of the vertebral body and part of the neural arch is described. The approach is posterior and from both sides of the spine. The posterior approach is used to remove the healthy part of the neural arch, mobilise the dura, divide involved nerve roots and carry out the posterolateral parts of the spinal osteotomies or disc divisions. On one side, usually the right, the sides of the vertebral body or bodies are freed and the osteotomies or disc divisions are extended. Then from the other side, a posterolateral thoracotomy or lumbotomy allows completion of the dissection with radical resection by rolling the specimen away from the dura. Ten operations are reported in which up to three and a half vertebrae were resected. Spinal reconstruction was by internal fixation and grafting preferably with vascularised bone. The results were satisfactory after follow-up for as long as eight years.

We describe a method of obtaining a biopsy from the body of a vertebra by an open transpedicular route. This minimises the danger of contamination of tissue planes and spaces.

Two cases of burst fracture of the upper lumbar spine are reported. In both cases the narrowing of the spinal canal shown by CT scans was progressively relieved by natural remodelling. The need for operative decompression should be assessed clinically and not from CT scans only.

We report the case of a carrier of the hepatitis B virus who required arthroscopy of the knee. The irrigation fluid was shown to contain the virus. In view of the highly infective nature of this virus, appropriate precautions are necessary when carrying out arthroscopy in such patients.

Seventeen patients with pathological fractures of the thoracolumbar spine which had not responded to conservative treatment are reported. All had compression of the spinal cord and/or severe pain. All (except one treated by lateral rhachotomy) were treated by anterior decompression followed by stabilisation; when the lesion was below T2 the spine was stabilised anteriorly, and when it was higher posterior instrumentation was used. Sixteen of the 17 patients benefited from the procedure.

Eleven patients with metastases in the cervical spine had operations for severe pain due to a pathological fracture which, in eight of the cases, was unstable. Conservative treatment had either failed or was unsuitable. In the first five patients internal fixation with tension band wires and bone grafts was supported by a halo-brace. The method has evolved to the use of posterior instrumentation with laminar wires from two levels above the lesion to two levels below. Stability is increased by the use of bone cement with or without bone autografts applied to one side of the spine. This technique enables the patient to get up within a few days of operation--a great advantage when life expectancy is limited. The operations were successful in all except one case.

A new technique for the transthoracic removal of a prolapsed intervertebral disc in the mid or lower thoracic spine is described. Investigations before operation include thoracic myelography, selective spinal angiography and CT scanning. Image intensification is used at operation to check the level of the prolapse. A tunnel in the coronal plane (vertebrotomy) is made through the posterolateral part of the disc and the adjacent vertebral bodies, to reach the spinal canal at the site of the prolapse. This gives good exposure and enables gentle removal of the disc prolapse and any associated osteophytes, under direct vision without need for retraction or pressure on the dura or spinal cord. Spinal stability is not compromised, and the blood supply of the cord is not disturbed. Five consecutive patients are reported, including one in whom the disc prolapse was calcified and had herniated into the spinal cord. All were treated successfully.

Arthrodesis after the removal of a knee prosthesis is often hampered by the small area of contact of the bony surfaces and by pre-existing infection. Conventional systems of external fixation and compression frequently fail to achieve stability but the addition of the Wagner leg-lengthening apparatus applied anteriorly and adjusted to give compression ensures rigid external fixation. Four knees in four patients were treated using this technique; the treatment followed the removal of infected prostheses in three knees and painful fibrous ankylosis after the removal of the prosthesis in the other. All obtained a sound arthrodesis.

At the apex of an idiopathic scoliotic curve there is a greater proportion of "slow twitch" muscle fibres in multifidus on the convex as compared to the concave side. To determine whether this represents a primary muscular imbalance relevant to the aetiology of idiopathic scoliosis or merely a secondary change, the lengths of multifidus on opposite sides of the curve were measured. Multifidus is shorter on the convex side. This is consistent with the theory of primary muscular imbalance, in which the more tonically acting muscle with its higher proportion of "slow twitch" fibres contracts and shortens as the deformity is produced. The paradox of multifidus being shorter on the convex rather than on the concave side is explained by consideration of its action.