OBJECTIVETo analyze the possible reasons for proximal junctional lordosis (PJL) after short-segment posterior pedicle screw fixation in lumbar spine and discuss its proper management.

METHODSFrom December 2001 to August 2005, 345 patients were treated by short-segment pedicle screw fixation and these patients were reviewed. Clinical outcome was evaluated according to Oswestry Disability Index (ODI). Proximal junctional lordosis was assessed evaluated on radiographs, by measuring lumbar lordosis angle, segmental angle at proximal level and lumbar-sacral angle. Risk factors of proximal junctional lordosis were analyzed.

RESULTSAll patients were followed-up for 2 to 6 years (average 3.8 years). ODI after lumbar surgery was 9.7-46.2 ( average 19.6 +/- 10.7). PJL was noted in 78 patients (22.6%), 37 (10.7%) of whom were symptomatic and 21 (6.1%) received revision surgery. PJL was more commonly occurred in patients over 60 years old, with reduced lumbar lordosis or vertical sacrum. The number of fusion-segment was not correlated to the occurrence of PJL.

CONCLUSIONSShort-segment posterior pedicle screw fixation can not improve lumbar sagittal alignment. Age over of 60 years, reduced lumbar lordosis and vertical sacrum are possible risk factors of PJL sacrum.