The posterior lumbar interbody fusion (PLIF) with cages in the treatment of segmental spinal instabilities.

Purpose: The technique of posterior lumbar interbody fusion (PLIF) has been critically discussed due to a high degree of complications, including the development of pseudarthrosis. With the recent establishment of intercorpor eal implants new aspects have to be contemplated in surgieal techniques, es pecially concerning the posterior approach. In this study we present our fi rst results after intercorporeal stabilisation of segmental spinal instabil ities utilising carbon and titanium cages. Method: 45 spinal instabilities were surgically stabilised in 42 patients who were evaluated on average for 2.8 years post-operatively. 12 patients had isthmic and 19 patients degene rative instabilities while 11 patients suffered from instabilities resultin g from prior spinal surgery. Results: Assessed according to the Hambly-scor e, 69% of the patients had an exzellent or good result; 2 (4.8%) patients w ere subjectively worse off than before surgical treatment. After implantati on of cages precise radiological evaluation of bony ingrowth is frequently impaired by artefacts. We found that three months after implantation of a t itanium cage, which had to be removed after incorrect placement, no bony co nsolidation was visible. Persisting or recurrent instabilities in fused seg ments were not recorded. Conclusion: By means of PLIF and implantation of c ages the interbody space is reconstructed and jeopardised neural structures are decompressed. In addition to this, the frequently osteochondrotically degenerated segment is immobilised. The posterior approach allows decompres sion of neural structures and, with comparable results concerning stability , the considerable risks of the ventral approach are avoided.