Report on two failed posterior lumbar interbody fusions

Despite X-ray and computed tomography signs of osseous stability after posterior lumbar interbody fusion (PLIF) procedures, the examination of two patients after 28 and 24 months respectively, revealed that the cages were wandering and consolidation had not taken place. Revision surgery was required in both cases. Introduction Fusion surgery in the region of the lumbar spine has become standard procedure during the last two decades. One of the most important indications is monosegmental degeneration with instability and stenosis problems [1, 2, 3]. The so-called SICOT Online Report E034 Accepted May 6th, 2003 2 Posterior Lumbar Interbody Fusion (PLIF) has become the preferred procedure when the dorsal osseous structures of the lumbar spine are weakened by specific decompression. Advantages are the exclusive access from the dorsal direction and the possibility of reaching and stiffening the ventral spine and avoiding the preparatory risks of ventral access [1, 2, 3, 4]. As a rule, two cages are provided for the ventral fusion. Fusion is achieved by axial load. The hollow spaces of the cages are filled with spongy bone, as is the area ventral to and between the cages. In addition, a dorso-lateral fusion is carried out. Two types of material have become accepted, i.e. the titanium implant on the one hand, and the so-called PEEK (polyetheretherketone) implants on the other hand [11,15].