<正>Objective:To evaluate the lumbar stability and the primary clinical results of unilateral facetectomy

transforaminal lumbar interbody fusion （TLIF） and unilateral pedicle screw fixation by X-Tube system.Methods: Five human lumbar cadaveric functional spine units（FSU） were obtained and graded facetectomy by 0

1/4

1/2

3/4 and 4/4 were performed respectively on the left articular process of them.The stability of these 5 models was evaluated at flexion

extension

lateral bending and axial rotation.After a serial of biomechanical researches

23 patients from June 2004 to March 2006 in our department underwent unilateral facetectomy

transforaminal lumbar interbody fusion （posterior lumbar interbody fusion） and unilateral pedicle screw instrumentation by X-Tube system.After general anaesthesia

with the guide of fluoroscopy and using X-Tube system

procedures of unilateral endoscopic facetectomy

spinal nerve root decompression

autologus spongy bone transplantation

one cage oblique insertion and unilateral pedicle screw instrumentation were performed.Results:There was no significant difference in flexion

extension

lateral bending and axial rotation of lumbar motion range after unilateral graded facetectomy.The stability of left/right axial direction was greatly affected when the range of graded facetectomy exceed 1/2.According to the Nakai criteria

for the 23 patients

the clinical result was excellent in 15 （65.2%）

good in 6 （26.1%） and fair in 2 （8.7%）.The fusion rate was 95.6% in excellent and good cases.Although partial absorption of bone grafts was observed in 1 case which might indicate a unsuccessful fusion

there was no loosing and replacement of instrument and no clinical symptoms occurred.Conclusion:The lumbar stability will be affected significantly when the range of graded facetectomy exceeds 1/2.Procedures of unilateral facetectomy

transforaminal lumbar interbody fusion and unilateral pedicle screw fixation is an optional strategy for microsurgical reconstruction

though the indications of the procedure should be carefully restricted.