Two-stage resection and spinal stabilization for aneurysmal bone cyst. A report of two cases

Two cases of aneurysmal bone cyst of the dorsal lumbar spine are presented with four- and seven-year follow-up periods. The lesion in each case involved the vertebral bodies and posterior elements and extended to contiguous bony structures. Both anterior and posterior staged procedures were required for maximal excision, rendering the spine extremely unstable at the involved levels. Anterior strut grafting with autogenous iliac bone was done during the first stage after the vertebral bodies had been curetted. Three weeks later the remaining dorsal elements and associated tumor were removed through a posterior approach, and the spine was stabilized with the Harrington compression-distraction system and posterior autogenous iliac crest grafts. Both patients were neurologically normal after operation, and the spines in both were stable and solidly fused. Both have remained symptom-free and have had no evidence of recurrence.

[Position of the spinal cord and the depth of the peridural space as a function of spinal column kyphosis and age]

A dry tap may occur when performing a spinal anaesthetic, especially when there is an extreme kyphosis. The puncture can be at normal level or higher. The reason for this is in our experience, excluding other known possibilities, is that spinal cord and the cauda equina come to lie dorsally against the dura. The cerebrospinal fluid is thereby displaced ventrally. This fact is especially important in anatomical length variations of the medulla spinalis. If all the causes for a dry tap are borne in mind then this can easily be prevented by a simple manoeuvre, which we describe in the text.

Vertebral osteochondrosis (Scheuermann's kyphosis)

Scheuermann's juvenile kyphosis may be considered a form of vertebral osteochondrosis. Although the etiology remains unknown, the ultimate effect is a disorderliness of vertebral growth in the growth plate cartilage. The biomechanical effects of increased kyphosis on saggital plane deformity, especially in a growing child, serve to aggravate this deformity.

Juvenile kyphosis: histological and histochemical studies

Histological and histochemical studies of the spine of a sixteen-year-old boy with juvenile kyphosis who was killed in an automobile accident showed abnormal cartilage in extensive areas of the vertebral and growth plates of the involved vertebrae. In these areas the cartilage matrix was loose, strongly positive when stained with alcian blue and weakly positive to periodic acid-Schiff, and it contained numerous chondrocytes. Some chondrocytes were irregularly shaped and others were in clusters. Vertebral bone growth was stunted under the areas of abnormal vertebral and growth plates. The ossification in the ring apophyses was irregular in areas of abnormal cartilage plate, but necrotic bone was not seen. Schmorl nodes had formed where areas of abnormal cartilage plate adjoining the nucleus pulposus had collapsed, allowing the disc material to herniate into the vertebral body.

CLINICAL RELEVANCE

The defective vertebral-bone formation in juvenile kyphosis appears to result from abnormal vertebral and growth-plate cartilage. The kyphosis and presumably also the cartilage abnormality can be improved during the florid stage of the disease by decreasing the postural load on the anterior part of the vertebrae with the use of a proper brace.

Scheuermann's kyphosis--long-term results of Milwaukee braces treatment

A review of 203 patients with Scheuermann's kyphosis is presented. The modified Milwaukee brace was used in 62 patients. Thirty-nine patients wore the brace for an average of 18 months. The pretreatment kyphosis averaged 62 degrees, and the curve at the completion of brace treatment averaged 41 degrees. Follow-up of more than 18 months after brace wear showed an average 15 degrees loss of correction. Wedging of the vertebral bodies improved from 7.9 degrees to 6.8 degrees with brace treatment. To provide permanent correction, vertebral wedging must improve to approximately 5 degrees. Most patients will require full-time brace wear of longer than 18 months to effect this improvement in vertebral wedging. The brace can improve kyphotic curves greater than 75 degrees.

Congenital kyphoscoliosis and spinal cord lesion produced in the rat by beta-aminopropionitrile

Pregnant rats received the lathyrogen beta-aminopropionitrile (1,500 mg/kg) intraperitoneally on day 16 (plug day = 0 day). Kyphoscoliosis was produced in a high incidence in the fetuses at the level of the upper thoracic spine as early as 24 hours after treatment. Although most of the affected newborns died within two weeks, survivors were studied until 20 weeks after birth. Survivors developed paraplegia in consequence of kyphoscoliosis. Both spinal deformity and motor disturbance were progressive. Biochemical and electron microscopic observations suggested that beta-aminopropionitrile treatment resulted in an inhibition of collagen formation in the spinal column and surrounding longitudinal ligaments of the fetuses six hours after the treatment. In addition, electron micrographs of vertebral bodies showed a decrease of proteoglycan granules in the extracellular matrix. Therefore, rupture and collapse of weakened ligaments and vertebral bodies might result in severe spinal deformity and spinal cord lesion.

Rheumatoid arthritis with rheumatoid heart disease and granulomatous aortitis

Aortic insufficiency and aortitis are frequent complications of ankylosing spondylitis but are considered rare in rheumatoid arthritis. A 49-year-old woman with severe rheumatoid arthritis had the cardiovascular changes common to both diseases. At autopsy, the heart and aorta showed granulomatous ane fibrinous pericarditis and epicarditis, "core" granulomas in the aortic valve cusps and mitral valve leaflets, and coronary arteritis. These are considered to be classical changes of rheumatoid carditis. In addition, there were mesoaortitis with obliterative endarteritis of the vasa vasorum and fibrosis of the aortic cusps with separation of the commissures. These are considered to be changes of ankylosing spondylitis. This case, therefore, represents a mixed form of cardiovascular involvement within the spectrum of the rheumatoid diseases.

The relationship of kyphosis to the shape of vertebral bodies

An index which measures the wedge deformity of vertebral bodies in lateral chest radiographs in older people was calculated by dividing the sum of the vertical anterior heights of the lower six thoracic vertebral bodies and discs by the corresponding sum of vertical posterior heights. This index increased with increasing age in a similar manner in men and in women, in contradistinction to an index measuring kyphosis in which the age effect was greater in women. The index of wedging explained 42 per cent and 48 per cent of the variation in kyphosis in men and in women respectively. Additional effects due to age, detected in women only, added a further 4 per cent to the explained variation and may be due to ageing of soft tissues.

Hemivertebra in the dog: clinical and pathological observations

The clinical and radiographic findings associated with the presence of hemivertebra ("wedge-shaped"vertebra) in small and brachycephalic breeds of dogs are reported together with the results of post mortem examination in the availabel cases. The condition is characterised clinically by progressive hind-leg weakness, spinal pain, abnormalities of the nervous system and evidence of muscle atrophy or other abnormalities of conformation. Confirmation of the clinical diagnosis is by radiography. It is suggested that the condition is congenital in origin. Breed incidences are reported. The occurrence of the disorder in certain families of dogs suggests also that it may be hereditary. Other congenital abnormalities are seen in some dogs affected by hemivertebrae.