Objective       To evaluate the feasibility and clinical efficacy of percutaneous kyphoplasty (PKP) through unilateral extrapedicular approach in treating severe osteoporotic vertebral compression fractures (OVCFs).      Methods       From Aug. 2004 to Oct. 2008

twenty-two patients (34 vertebrae) with severe OVCFs were treated by PKP through unilateral extrapedicular approach. Of the 22 patients

there were 7 males and 15 females with an average age of 61.8 years (52-74 years). The onset of severe back pain was 2 to 6 months before admission. Severe OVCFs were confirmed when the vertebral collapse was more than two-thirds of the original vertebral height. Pain relief

spinal function

and restoration of vertebral height and kyphosis’ correction were evaluated by comparison before and after operation using visual analogue scale (VAS)

Oswestry disability index (ODI)

and radiography

respectively.      Results       All 22 cases underwent operation successfully with average injected bone cement 2.7 ml. The mean time of follow-up was 34.2 months (18-66 months). The patients’ VAS and ODI scores were significantly improved after operation (P0.05). The average height restoration of vertebral anterior border and midline and the average correction of kyphosis were 2.3±0.6 mm and (1.8±0.4)°. Bone cement extravasation was found in 2 cases without any clinical symptoms and signs.      Conclusion      PKP through unilateral extrapedicular approach is effective and relatively safe for the treating severe OVCFs.