OBJECTIVETo investigate the advantages and disadvantages of unilateral pedicle screw fixation combined with contralateral translaminar facet screw fixation and interbody fusion with cages in the treatment of two-level lumbar vertebra diseases, by comparing bilateral pedicle screw fixation and interbody fusion with cages.

METHODSForty-nine patients with two-level lumbar diseases who received treatments from June 2009 to December 2011 were included in this study. Among these patients, 23 patients received unilateral pedicle screw fixation combined with contralateral translaminar facet screw fixation and interbody fusion with cages (combined fixation group) and the remaining 26 patients underwent bilateral pedicle screw fixation and interbody fusion with cages (bilateral fixation group). These patients consisted of 17 males and 32 females, ranging in age from 29 to 68 years old. Among these patients, lumbar intervertebral disc herniation accompanied by the spinal canal stenosis was found in 29 patients, degenerative lumbar disc diseases in 17 patients and lumbar degenerative spondylolisthesis (degree I) in 3 patients. The lesions occurred at L2,3 and L3,4 segments in 1 patient, at L3,4 and L4,5 segments in 30 patients, and at L4,5 segment and L5S1 segment in 18 patients. Wound length, operation time, intraoperative blood loss and postoperative wound drainage were compared between two groups. Intervertebral space height in the lesioned segment before and during surgery and at the latest follow up was also compared between two groups. Before surgery and at the latest follow-up, the Cobb angle of the coronal plane and sagittal plane of the lumbar spine, loosening or breakage of internal fixations, the dislocation of intervertebral cages, and interbody fusion were all evaluated in each group. The visual analogue scale (VAS) was used to measure lumbar incision pain. The Japanese Orthopedic Association (JOA) scoring system was used to evaluate the function before surgery and at the latest follow-up.

RESULTSNo wound infection or skin necrosis was observed after surgery in all patients. No cerebrospinal fluid leakage, nerve root injury, cauda equia injury or worsened neural function in the lower limb occurred in all patients during and after surgery. Wound length, operation time, intraoperative blood loss and postoperative wound drainage in the combined fixation group were superior to those in the bilateral fixation group. At postoperative 72 hours, the VAS score in the combined fixation group (1 to 4 points, mean 2.35±1.20) was significantly lower than that in the bilateral fixation group (2 to 5 points, mean 3.11±1.00; P<0.05). All the patients were followed up for 12 to 48 months, with a mean of 29 months. After surgery, intervertebral space height was well recovered in each patient and it was well maintained at the latest follow-up, and there was no significant difference between two groups (P>0.05). During follow-up, pedicle screw and translaminar facet screw loosening, dislocation or breakage and dislocation of intervertebral cages were all not found. At the latest follow-up, the Cobb angle of the coronal plane and sagittal plane of the lumbar spine was obviously improved and was not significantly different between two groups (P>0.05). The lumbar interbody fusion rate was 93.5% and 96.2% in the combined fixation group and bilateral fixation group, respectively, and there was no significant difference between them (P>0.05). There was a significant difference in JOA score between before surgery and at the latest follow-up in each patient (P<0.05), and at the latest follow-up, significant difference in JOA score was found between two groups (P<0.05).

CONCLUSIONCompared to bilateral pedicle screw fixation and lumbar interbody fusion with cages, unilateral pedicle screw fixation combined with contralateral translaminar facet screw fixation and lumbar interbody fusion with cages shows advantages including small skin incision, minimal invasion, ease of operation, highly reliable stability, high interbody fusion rate, rapid recovery in the treatment of two-level lumbar vertebra diseases and therefore can be preferred as a treatment method of this disease.