Does right lateral decubitus position change retroperitoneal oblique corridor? A radiographic evaluation from L1 to L5.
To determine if the retroperitoneal oblique corridor will be affected by right lateral decubitus position.



Forty volunteers were randomly enrolled and MRI scan was performed from L1 to L5 in supine and right lateral decubitus positions, respectively. In images across the center of each disc, O was defined as the center of a disc and A (supine) or A' (right lateral decubitus) was located in left lateral border of the aorta or the iliac artery; B (supine) or B' (right lateral decubitus) was on the anterior medial border of the psoas. The distance of AB and A'B' (Recorded as A-Ps and A-Pr, respectively) at each level was recorded and compared to each other. The relationships between A-Pr, sex, BMI and relative psoas cross-sectional area (PCSA) at each level were also evaluated.



A-Pr was significantly smaller than A-Ps at L1/2, L2/3 and L3/4 (All p < 0.05); there was no significantly difference of A-Pr between all levels (p = 0.105), but L1/2 seemed to be larger than L3/4, followed by L2/3 and L4/5; A-Pr at each level was not affected by sex (All p > 0.05); linear relationships were found between A-Pr, BMI and PCSA at L1/2 and L3/4.



ROC at L1/2, L2/3 and L3/4 will significantly decrease from supine to right lateral decubitus position and the reason may be due to the relaxed psoas deformation. Using MRI images in supine position for pre-operatively ROC evaluation is not accurate. Spine surgeon should also be more cautious when OLIF is performed at L4/5 where ROC is the smallest. Patients from Asia and those with strong psoas major at L1/2 and L3/4 are also associated with relatively narrow ROC.
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China.
Fan
F
Zhang
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China.
Haocheng
H
Xu
Shanghai Medical College, Fudan University, Shanghai, China.
Bo
B
Yin
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China.
Hongyue
H
Tao
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China.
Shuo
S
Yang
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China.
Chi
C
Sun
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China.
Yitao
Y
Wang
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China.
Jun
J
Yin
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China.
Minghao
M
Shao
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China.
Hongli
H
Wang
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China.
Xinlei
X
Xia
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China.
Xiaosheng
X
Ma
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China. lufeizhou@hotmail.com.|The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China. lufeizhou@hotmail.com.
Feizhou
F
Lu
Department of Orthopedics, Huashan Hospital, Fudan University, No. 12 Wulumuqi Middle Road, Shanghai, China.
Jianyuan
J
Jiang
D000328:Adult; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning; D016658:Psoas Muscles / Q000000981:diagnostic imaging* / Q000502:physiology; D055815:Young Adult
OLIF; Oblique corridor; Position change