OBJECTIVETo explore the clinical effect of transforaminal lumbar interbody fusion (with single cage) combined with unilateral pedicle screw fixation in treating lumbar instability.

METHODSThe clinical data of 50 patients with lumbar instability were retrospectively analyzed. They underwent treatment and obtained following up more than 8 months from 2009 to 2012. All patients complicated with refractory or recurrent lower back pain, and unilateral primarily or unilateral lower limb radiation pain, X-ray and CT films showed lumbar instability. The patients were respectively treated with transforaminal lumbar interbody fusion (with single cage) combined with unilateral or bilateral pedicle screw fixation. According to different fixation methods, they divided into unilateral fixation group and bilateral fixation group. There were 20 patients with 22 intervertebral spaces in unilateral fixation group, 8 males and 12 females, aged from 26 to 66 years old, 2 cases with isthmic spondylolisthesis of degree I, 8 cases with degenerative spondylolisthesis, 10 cases with lumbar disc herniation; fusion location with L3,4 was in 1 case, L4,5 was in 12 cases, L5S1 was in 9 cases. There were 30 patients with 30 intervertebral spaces in bilateral fixation group, 14 males and 16 females, aged from 41 to 62 years old, 4 cases with isthmic spondylolisthesis of degree I,14 cases with degenerative spondylolisthesis, 12 cases with lumbar disc herniation; fusion location with L3,4 was in 3 cases, L4,5 was in 15 case, L5S1 was in 12 cases. Operation time, intraoperative blood loss, postoperative drainage, complications were analyzed and intervertebral height, lordosis angle changes, fusion rate and clinical effect were compared between two groups.

RESULTSAll incisions obtained primary healing,lower limb radiation pain and low back pain disappeared basically, no infection, endorachis injury was found. Foot drop occurred in one case of bilateral fixation group and no iatrogenic neurological symptom was found in unilateral fixation group. All patients were followed up from 8 to 18 months with an average of (10.8?4.3)months. Ac- cording to JOA score improvement rate (RIS) to assess clinical effect, all patients got excellent and good results, there was no statistically significant difference between two groups. Two methods can both effectively increase the pathological intervertebral height. Unilateral fixation group was better than bilateral fixation group in aspect of operation time, intraoperative blood loss and postoperative drainage.

CONCLUSIONWith strict indication and good skills, transforaminal lumbar interbody fusion (with single cage) combined with unilateral pedicle screw fixation in treating lumbar instability has advantages of smaller traumatic, less blood loss, faster recovery for the patient and can reduce the economic cost.