[Unilateral fixation combined with interbody fusion for the treatment of lumbar degenerative instability via a paraspinal intermuscular approach under MAST Quadrant retractor].

OBJECTIVE: To study clinical effects of unilateral pedicle screw-rod system fixation combined with the single the cage of interbody fusion in the treatment of lumbar degenerative instability via paraspinal intermuscular approach under MAST Quadrant retractor.

METHODS: From February 2010 to December 2011, 39 patients with lumbar degenerative instability after invalid conservative treatment were treated with unilateral fixation combined with interbody fusion via the paraspinal intermuscular approach under MAST Quadrant retractor. The indexes such as the operative time, blood loss, complications, VAS pain scores, JOA (subjective symptoms of low back pain,lower limb pain and numbness, sensory disturbance, movement disorders) scores, modified Macnab criteria for curative effect evaluation were observed before treatment, at the 1st month after treatment and the latest follow-up. The intervertebral fusion was studied on the X-ray at the latest follow-up.

RESULTS: All the patients were followed up, and the mean during was (22.3 +/- 8.6) months. The operation time was (138 +/- 46) min, and the amount of bleeding was (335 +/- 152) ml. There were no complications such as cerebrospinal fluid leakage and spinal nerve injury during operation, and no incision infection after operation. The VAS pain score was reduced from preoperative 7.93 +/- 1.27 to 2.05 +/- 1.18 on the 1st month after operation and 1.89 +/- 0.42 at the latest follow-up. The JOA total score was improved from preoperative 1.59 +/- 0.42 to 8.86 +/- 0.37 on the 1st month and 9.02 +/- 0.29 at the latest follow-up. According to modified Macnab criteria, there were 17 cases got an excellent result, 19 good, 3 case fair. Thirty-five patients got intervertebral bony fusion at the latest follow-up.

CONCLUSION: Unilateral pedicle screw-rod system fixation combined with single cage interbody fusion in the treatment of lumbar degenerative instability via paraspinal intermuscular approach under MAST Quadrant retractor is a safe, minimally invasive, satisfactorily effective methods to treat lumbar degenerative instability.