OBJECTIVETo explore relationship between volume of bone cement injection and concurrent of fracture after thoracolumbar osteoporotic vertebral fracture treated by percutaneous kyphoplasty (PKP).

METHODSFrom January 2006 to December 2008,68 patients with thoracolumbar osteoporotic vertebral fracture treated by PKP were retrospectively analyzed. Among them, 30 patients with less than 3 ml bone cement injection (mean 2.5 ml, low group), including 11 males and 19 females, with an average age of (85.0 +/- 8.5) years (ranging for 60 to 91); 38 cases with over 4 ml bone cement injection (mean 4.5 ml, large group), including 15 males and 23 females,with an average age of (86.0 +/- 9.2) years (ranging for 60 to 93). Factors of concurrent vertebral fractures were observed during follow-up.

RESULTSAll patients were followed up from 3.4 to 5.1 years with an average of 3.8 years. Thirteen patients (43.3%) co-occurred fracture in low group,among which strengthened concurrent vertebral fracture occurred in 1 case,upper and lower section adjacent vertebral fracture in 8 cases,distal segment of vertebral fracture in 4 cases; while 18 patients (47.3%) co-occurred fracture in large group,among which strengthened concurrent vertebral fracture occurred in 2 cases, upper and lower section adjacent vertebral fracture in 10 cases,distal segment of vertebral fracture in 6 cases. No significant difference between two groups (P > 0.05).

CONCLUSIONBone cement injection is not main influence factors for treating concurrent of fracture after thoracolumbar osteoporotic vertebral fracture by PKP. Concurrent fracture mainly relates with progress of osteoporosis, the volume of injection volume may appropriately over the volume of balloon.