Atlantoaxial subluxation in different intraoperative head positions in patients with rheumatoid arthritis.
BACKGROUND
Disorders of the cervical spine are often observed in patients with rheumatoid arthritis (RA). However, the best head position for RA patients with atlantoaxial subluxation in the perioperative period is unknown. This study investigated head position during general anesthesia for the patients with RA and proven atlantoaxial subluxation.


METHODS
During anesthesia of patients with RA and proven atlantoaxial subluxation, the authors used fluoroscopy to obtain a lateral view of the upper cervical spine in four different positions: the mask position, the intubation position, the flat pillow position, and the protrusion position. Copies of the still fluoroscopic images were used to determine the anterior atlantodental interval, the posterior atlantodental interval, and the angle of atlas and axis (C1-C2 angle).


RESULTS
The anterior atlantodental interval was significantly smaller in the protrusion position (2.3 mm) than in the flat pillow position (5.1 mm) (P < 0.05). The posterior atlantodental interval was significantly greater in the protrusion position (18.9 mm) than in the flat pillow position (16.2 mm) (P < 0.05). The C1-C2 angle was, on average, 9.3 degrees greater in the protrusion position than in the flat pillow position (P < 0.05).


CONCLUSIONS
This study showed that the protrusion position using a flat pillow and a donut-shaped pillow during general anesthesia reduced the anterior atlantodental interval and increased the posterior atlantodental interval in RA patients with atlantoaxial subluxation. This suggests that the protrusion position, which involves support of the upper cervical spine and extension at the craniocervical junction, might be advantageous for these patients.
Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. dai@koto.kpu-m.ac.jp
Daisaku
D
Tokunaga
Hitoshi
H
Hase
Yasuo
Y
Mikami
Tatsuya
T
Hojo
Kazuya
K
Ikoma
Yoichiro
Y
Hatta
Masashi
M
Ishida
Daniel I
DI
Sessler
Toshiki
T
Mizobe
Toshikazu
T
Kubo
D000328:Adult; D000368:Aged; D000768:Anesthesia, General / Q000379:methods*; D001172:Arthritis, Rheumatoid / Q000503:physiopathology* / Q000601:surgery; D001268:Atlanto-Axial Joint / Q000503:physiopathology*; D005260:Female; D006257:Head; D006801:Humans; D007432:Intraoperative Period; D004204:Joint Dislocations / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011187:Posture