Myelopathy resulting from the atlantodental hypertrophic osteoarthritis accompanying the dens hypertrophy. Two case reports

STUDY DESIGN

This is a report of two patients who sustained cervical myelopathy that seemed to be associated with hypertrophic atlantodental osteoarthritis accompanying dens hypertrophy.

OBJECTIVES

Pathogenesis of hypertrophic osteoarthritis in the atlantodental articulation was elucidated, and these two patients were treated by C1 decompressive laminectomy with or without posterior fusion.

SUMMARY OF BACKGROUND DATA

One case of myelopathy resulting from the hypertrophic nonunion of the dens has been reported, but to the authors' knowledge, there have been no reports describing a case similar to those presented in this report.

METHODS

History, physical findings, and image examination findings common to the two cases were analyzed to elucidate pathogenesis of hypertrophic osteoarthritis in the atlantodental articulation. C1 decompressive laminectomy alone was performed in one patient and additional atlantoaxial transarticular fixation in the other patient.

RESULTS

Myelopathy in two patients was caused by the cervical cord compressed between the hypertrophic and sclerotic dens and the anteriorly displaced posterior arch of the atlas in the developmentally small atlas ring. Postoperative neurologic recovery was satisfactory with the atlantoaxial solid fusion.

CONCLUSION

The atlantodental hypertrophic osteoarthritis accompanying the dens hypertrophy seemed to have developed because of post-traumatic atlantoaxial instability. Their developmentally small atlas ring may be a predisposing factor toward the development of myelopathy.

Stress fractures of the medial malleolus: a case report

The findings for stress fracture of the medial malleolus in two patients are presented. In case 1, a 54-year-old woman complained of gradual onset of pain over the medial malleolus after prolonged walking. Magnetic resonance imaging was useful in the early detection of the stress fracture of the medial malleolus. In case 2, a 16-year-old male developed stress fracture of the medial malleolus during repetitive Kendo fencing activity. Good clinical results were obtained with nonsurgical therapy.

Radiolucent bone cysts and the type of dialysis membrane used in patients undergoing long-term hemodialysis

The relationship between the types of dialysis membrane used and the prevalence and severity of radiolucent bone cysts (which are a main radiological feature of dialysis amyloidosis) was studied in 30 patients on hemodialysis for more than 10 years. One of them was treated exclusively with cuprophane; the other 29 were dialyzed with cuprophane, and then treated with polyacrylonitrile AN 69. In 12 of the 30 patients, radiolucent bone cysts (at least 5 mm in diameter in the wrists and at least 10 mm in the shoulders or hips) were observed. The patients with bone cysts spent significantly more time on cuprophane dialysis and significantly less time on AN 69 dialysis than the group of patients without bone cysts. Nine of the 14 patients who had been treated with cuprophane for more than 8 years had bone cysts; whereas bone cysts were observed in only 2 of the 12 patients dialyzed for more than 8 years with AN 69. The frequency of bone cysts was significantly different for each of the two groups. There was, however, no significant difference in the total duration of dialysis between the two groups. The severity of the cystic bone lesions correlated positively with the duration of dialysis using cuprophane and negatively with the duration of dialysis using AN 69. These findings suggest that the development of osteoarticular amyloidosis may be related to the type of dialysis membrane used. Hemodialysis using AN 69 membranes may prevent, or at least postpone the development of dialysis amyloidosis.

[Microneurographic study of sympathetic nerve activity of the lower leg in lumbar spine diseases]

Sympathetic nerve activity was recorded with micro-neurography, and this activity in lumbar spine disease was evaluated. The recording was made with 2-5 omega impedance tungsten microelectrodes in human common peroneal nerve. Sympathetic nerve activity was expressed as bursts numbers per minute, and bursts per 100 heart beats. For the skin sympathetic nerve activity, reflex latencies were 0.80 +/- 0.16 seconds. These values were clearly longer than those of myelinated A fiber, reflecting the conduction velocities of unmyelinated C fiber that forms postganglionic sympathetic fiber. Muscle sympathetic nerve activity in lumbar spine disease with leg symptoms increased in comparison with other subjects. These results suggest this condition induces latent ischemia of the leg that may cause coldness or numbness in the leg.