OBJECTIVETo evaluate the clinical outcomes of minimally invasive posterior lumbar interbody fusion (PLIF) assisted by X-Tube system for the management of degenerative lumbar diseases.

METHODSA total of 31 patients, 17 male and 14 female with ages from 38 to 75 (average 54.2 years), underwent minimally invasive PLIF assisted by the X-Tube system from May 2005 to March 2006. The index diagnosis was lumbar spondylolisthesis in 14 cases, spinal stenosis in 8 cases, separation of the posterior ring apophysis in 5 cases, intervertebral space stenosis with disk herniation in 4 cases. Before operation, conservative management for at least 6 months was proved to be failure in all these patients. The operative duration and blood loss were estimated . The changes of postoperative serum level of creatinine kinase was measured as well, and compared with the control group of 31 cases who were managed with traditional open PLIF operation during the same period at our department. The clinical functional outcomes were evaluated according to Oswestry disability questionnaire.

RESULTSThe operation lasted for 140-225 min, with a mean duration of (176 +/- 22) min. Blood loss during the operation was 270-750 ml, with a mean of (406 +/- 96) ml. Postoperative serum level of creatinine kinase was obviously lower in minimally invasive PLIF cases than in the open control cases. Although 2 pedicle screws in 2 cases were not in ideal position, there was no nerve root irritation or fixation failure and hence no revision was required. One case with spinal stenosis complained of numbness in the area dominated by left L5 nerve root after operation, but the symptom was relieved within 2 weeks through conservative management. All the 31 patients were followed up for 7-17 months, with a mean duration of 12.2 months. Lumbar radiography, and three-dimensional CT reconstruction in some cases, was performed and revealed solid fusion of the surgical segments half a year after the operation. The average Oswestry scores decreased from preoperative 40.6 +/- 5.1 to 17.4 +/- 6.5 at the first postoperative day and to 9.5 +/- 4.0 at the final follow-up. The outcome of this operation were rated as excellent.

CONCLUSIONSMinimally invasive PLIF assisted by X-Tube system has the characteristics of less blood loss, tissue trauma and operative time, quick recovery and bony fusion. The short-term outcomes are excellent.