Pathologic mechanism of experimental scoliosis in pinealectomized chickens.
METHODS
This study was designed to investigate the pathologic mechanisms of idiopathic scoliosis using experimentally induced scoliosis in chickens.


OBJECTIVE
To understand the process of producing a scoliotic deformity in pinealectomized chickens.


BACKGROUND
Pinealectomy in chickens consistently produces scoliosis with anatomic characteristics similar to those of human idiopathic scoliosis. Pinealectomized chickens are an important animal model for the study of idiopathic scoliosis.


METHODS
In this study, 40 chickens were divided into two groups; 20 chickens treated with pinealectomy and 20 with a sham operation as control subjects on the second after hatching. The chickens in both groups then were killed at intervals ranging from 1 to 20 weeks after surgery. Their spines were examined visually and radiologically for the presence of a scoliotic curve and vertebral deformities.


RESULTS
Rotational lordoscoliosis developed in pinealectomized chickens. The chickens with severe scoliosis were characterized by apically wedge-shaped vertebrae. In contrast, no scoliosis with any vertebral deformity developed in any of the chickens that received a sham operation.


CONCLUSIONS
Because there normally is evidence of lordosis in the thoracic spine of chickens, the rotational instability of the spine induced by pinealectomy may produce a scoliotic deformity as a secondary phenomenon. Pinealectomy in chickens consistently produces scoliosis with anatomic characteristics similar to those of human idiopathic scoliosis. The authors believe that disturbance of the equilibrium and the posture mechanism associated with a defect in melatonin synthesis after pinealectomy may promote the development of rotational lordoscoliosis.
Machida
M
M
Department of Orthopaedic Surgery and Biochemistry, Nihon University School of Medicine, Tokyo, Japan.
Dubousset
J
J
Satoh
T
T
Murai
I
I
Wood
K B
KB
Yamada
T
T
Ryu
J
J
D000818:Animals; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology; D002645:Chickens; D004195:Disease Models, Animal; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D008141:Lordosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D010870:Pineal Gland / Q000601:surgery*; D011201:Poultry Diseases / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D011859:Radiography; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D013045:Species Specificity; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology