OBJECTIVE: To study the effects of unilateral graded facetectomy on lumbar stability through biomechanical analysis. The primary clinical results of unilateral facetectomy, posterior lumbar interbody fusion and unilateral pedicle screw instrumentation using X-tube system were also evaluated. METHODS: 5 functional spinal units (FSU) from fresh cadavers of 5 adults were made, divided into 5 groups to remain intact, or with the lateral 1/4, 1/2, or 3/4 or the whole of the left L4/5 articular process, and then put in the biomechanical testing apparatus to evaluate the effects of operation on the lumbar motion range of flexion, extension, lateral bending and axial rotation. Twenty-three patients, 16 males and 7 females, aged 47.7 (32 - 74), underwent unilateral facetectomy, posterior lumbar interbody fusion, and unilateral pedicle screw instrumentation using X-tube system. The clinical outcomes of the 23 patients were assessed by use of the visual analog score (VAS), Oswestry disability index (ODI), and Nakai criteria. RESULT: The experiment of the 5 FSUs showed that no significantly negative effects on the change in lumbar motion range of flexion, extension after unilateral graded facetectomy (all P > 0.05), and the stability of lateral bending and axial rotation had been greatly affected with the range of graded facetectomy exceeding 1/2 (P < 0.05). According to the Nakai criteria, the clinical effect was excellent in 15 cases (65.2%), good in 6 cases (26.1%), and fair in 2 cases (8.7%). The excellent and good cases accounted for 91.3% with a fusion rate of 95.6%. CONCLUSION: The lumbar stability is significantly affected if the range of graded facetectomy exceeds 1/2. The use of procedures of unilateral facetectomy, diskectomy, spinal nerve root decompression, autologous bone grafting, and unilateral pedicle screw fixation using X-tube is an optional strategy for minimally invasive spine technique.
OBJECTIVE: To study the effects of unilateral graded facetectomy on lumbar stability through biomechanical analysis. The primary clinical results of unilateral facetectomy, posterior lumbar interbody fusion and unilateral pedicle screw instrumentation using X-tube system were also evaluated. METHODS: 5 functional spinal units (FSU) from fresh cadavers of 5 adults were made, divided into 5 groups to remain intact, or with the lateral 1/4, 1/2, or 3/4 or the whole of the left L4/5 articular process, and then put in the biomechanical testing apparatus to evaluate the effects of operation on the lumbar motion range of flexion, extension, lateral bending and axial rotation. Twenty-three patients, 16 males and 7 females, aged 47.7 (32 - 74), underwent unilateral facetectomy, posterior lumbar interbody fusion, and unilateral pedicle screw instrumentation using X-tube system. The clinical outcomes of the 23 patients were assessed by use of the visual analog score (VAS), Oswestry disability index (ODI), and Nakai criteria. RESULT: The experiment of the 5 FSUs showed that no significantly negative effects on the change in lumbar motion range of flexion, extension after unilateral graded facetectomy (all P > 0.05), and the stability of lateral bending and axial rotation had been greatly affected with the range of graded facetectomy exceeding 1/2 (P < 0.05). According to the Nakai criteria, the clinical effect was excellent in 15 cases (65.2%), good in 6 cases (26.1%), and fair in 2 cases (8.7%). The excellent and good cases accounted for 91.3% with a fusion rate of 95.6%. CONCLUSION: The lumbar stability is significantly affected if the range of graded facetectomy exceeds 1/2. The use of procedures of unilateral facetectomy, diskectomy, spinal nerve root decompression, autologous bone grafting, and unilateral pedicle screw fixation using X-tube is an optional strategy for minimally invasive spine technique.