Objective      To evaluate the biomechanical stability of allogeneic fibula ring lumbar interbody fusion cage for posterior lumbar fusion.       Methods      Thirty-five fresh human lumbar spine specimens of segment 4 and 5 were collected. Spinal tumors

trauma and osteoporosis were excluded by imaging examination before the experiment

and the implantation of lumbar interbody fusion through posterior intervertebral foramen was simulated. There were 7 experimental groups (n=5) including: ① normal group (complete specimen

intact)

② implantation of two titanium alloy anatomic fusion cages (two titanium alloy anatomical fusion cages

two TAAFC)

③ implantation of two titanium alloy anatomic fusion cages combined with posterior pedicle screw fixation (two TAAFC and posterior pedicle screw system

two TAAFC and PPSS)

④ implantation of two allogeneic fibular ring fusion cages (two allogeneic fibula ring fusion cages

two AFRFC)

⑤ implantation of two allogeneic fibular ring fusion cages combined with posterior pedicle screw fixation (two AFRFC and posterior pedicle screw system

two AFRFC and PPSS)

⑥ implantation of three allogeneic fibular ring fusion cages (three AFRFC)

and ⑦ implantation of three allogeneic fibular ring cages combined with posterior pedicle screw fixation (three AFRFC and PPSS). Spine three-dimensional motion testing machine was applied to test the movement range of lumbar segment 4/5 in the directions of axial pressure

flexion

extension

lateral bending and rotation with the same load

and anti-axial pressure damage test was applied to examine the mechanical limits of the axial pressure of the end plate and two and three AFRFC.       Results      Axial pressure test: the two TAAFC and PPSS group was significantly different from the two AFRFC and PPSS group (

P

0.01)

but was not significantly different from the three AFRFC and PPSS group (

P

0.05). The two TAAFC group was significantly different f

rom the two AFRFC group (

P

0.05)

but was not significantly different from the three AFRFC group (

P

0.05). Flexion test: the two TAAFC group was significantly different from the two AFRFC group (

P

0.05)

but was not significantly different from the three AFRFC group (

P

0.05). Extension

lateral bending and rotation tests: the two AFRFC and PPSS group was not significantly different from the two TAAFC and PPSS group and three AFRFC and PPSS group

and the two AFRFC group was also not significantly different from the two TAAFC group and three AFRFC group. Compression damage test: the maximum load of vertebral endplate was 13 649.50±942.06 N

the maximum axial load of single AFRFC was 13 472.72±518.11 N

the maximum axial load of double AFRFC was 22 658.33±554.92 N

and the maximum load of three AFRFC was 25 384.50±687.64 N.       Conclusion      Intervertebral implantation of 2 or 3 AFRFC combined with pedicle screw fixation may allow the spine to obtain good mechanical stability.