OBJECTIVETo evaluate the mid-term clinical outcomes of minimally invasive transforaminal lumbar interbody fusion (TLIF) with unilateral pedicle screw fixation for lower lumbar degenerative diseases.

METHODSFrom April 2004 to December 2005, minimally invasive TLIF through paramedian approach with unilateral pedicle screw fixation was performed in a consecutive series of 43 patients, including 24 male and 19 female, aging from 38 to 71 years, with an average age of 49 years. The length of surgical incision was 3 cm. The operation level at L(3-4) were 3 cases, L(4-5) 27 cases, L(5)-S(1) 13 cases and no case was at multilevel. Clinical outcomes were assessed by ODI scores and JOA questionnaires before and after operation. Operation time, intraoperative blood loss, incision status and complications were recorded. Radiological examination was obtained for each patient to assess the height of intervertebral space, postoperative intervertebral fusion conditions and the degeneration of adjacent segments.

RESULTSThe mean operation time was 110 minutes, the mean blood loss was 150 ml and all the incisions were healed primarily. The follow-up time ranged from 36 to 58 months. The ODI scores decreased significantly from 60 ± 10 preoperatively to 12 ± 4 postoperatively (P < 0.01). The JOA scores were improved remarkably from 9.6 ± 2.2 preoperatively to 23.8 ± 2.0 postoperatively (P < 0.01) and the proportion with optimal effect was 86%. The ventral and dorsal heights of intervertebral disc were significantly higher than those before operation (P < 0.01). The fusion rate was 94%. The incidence of adjacent segment degeneration was 17%. There were no complications such as secondary scoliosis, screw loosening, internal fixation failure and cage slippage.

CONCLUSIONSThe minimally invasive TLIF through paramedian approach with unilateral pedicle screw fixation is an effective and convenient method with little surgical trauma. The mid-term follow up results showed favorable outcomes in patients receiving this surgery.