OBJECTIVETo compare the clinical effects of unilateral pedicle screw fixation (uni-PS) assisted by Quadrant system and bilateral pedicle screw fixation (bi-PS) for the treatment of lumbar degenerative diseases.

METHODSFrom October 2008 to October 2010,102 patients with lower back pain, unilateral lower limb radiating pain or paraesthesia were treated with pedicle screw fixation and lumbar interbody fusion. There were 67 males and 35 females with an average age of 51.5 years ranging from 34 to 69 years. The patients were randomly divided into two groups (group A and group B) according to the internal fixation type. The patients of group A (n=50) underwent with minimally transforaminal lumbar interbody fusion (TLIF) and unilateral pedicle screw fixation with one single cage placement assisted by Quadrant system;and the patients of group B (n = 52) underwent with posterior lumbar interbody fusion (PLIF) and bilateral pedicle screw fixation with one single cage placement. There were no significant differences between two groups in general information (P > 0.05). VAS score and ODI score system were used to evaluate the preoperative and postoperative pain and function recovery. Operative time, volume of blood loss, fusion rate and complication rate were compared and analyzed by statistical test.

RESULTSAll the patients were followed up from 12 to 21 months with an average of 18.2 months. In the group A,operative time and volume of blood loss were (87.6 +/- 25.5) min and (105.7 +/- 27.2) ml, respectively; VAS score of low back pain and leg pain, ODI score decreased respectively from preoperative 7.2 +/- 1.4, 7.9 +/- 1.1, 42.2 +/- 11.8 to 3.2 +/- 0.6, 3.0 +/- 0.7,15.6 +/- 2.3 at one month after operation; the fusion rate was 96.0% (48/50) and the complication rate was 4.00% (2/50). In the group B,operative time and volume of blood loss were (160.3 +/- 20.5) min and (220.6 +/- 25.5) ml, respectively; VAS score of low back pain and leg pain, ODI score decreased respectively from preoperative 7.3 +/- 1.1, 8.1 +/- 0.9, 43.1 +/- 12.0 to 3.3 +/- 0.4, 3.2 +/- 0.3, 14.9 +/- 2.6; the fusion rate was 96.2% (50/52) and the compli- cation rate was 5.77% (3/52). There were no statistically significant differences between the two groups in fusion rate, complication rate, VAS pain and ODI score. Whereas the operative time and blood loss in group A were significantly lower than that of group B.

CONCLUSIONMinimally invasive unilateral pedicle screw fixation is a safe and feasible method for the treatment of lumbar degenerative diseases. It is as effective as the bilateral fixation in lumbar spinal fusion. In addition, it has the advantages of short operative time, less volume of blood loss, high fusion rate, etc.