Abstract
We considered three different device systems for the treatment of lumbar and lumbosacral instability. From a prospective database in use in our Institution, we obtained a 45-patient cohort of individuals who received a one-level lumbar or lumbosacral fusion procedure between 1995 and 1998. All patients had presented with disabling back and/or radicular pain and severe degenerative changes at one disc level or low-grade spondylolisthesis.
First group: 15 patients, six male and nine female, with an average age of 41 years, were treated by an interbody fusion using cylindrical threaded cages; the levels fused were L5-S1 in 10 patients and at L4-L5 in five.
Second group: 15 patients, eight male and seven female, with an average age of 39 years were treated by nine cylindrical, threaded cages and seven square cages, combined with posterior pedicle screws; the levels fused were L5-S1 in 11 and L4-L5 in four.
Third group: 15 patients, eight male and seven female, with an average age of 40 years, underwent posterolateral fusion with posterior pedicle screws instrumentation alone; the levels fused were L5-S1 in 10 and L4-L5 in the remaining five.
At a mean follow-up of 8 years in the first group, eight patients (53%) required a second operation (five posterior instrumentation, two root decompression and one repair of dural tear). The clinical results were fair in six patients (40%) and poor in three (20%); five patients (33%) presented uncertain fusion signs. In the second group, two patients (13%) required a second operation (one root decompression and one dural repair). All patients (100%) presented definite fusion signs. The clinical results 6.5 years after primary surgery were fair in two (13%) patients and poor in two (13%). In the third group, two patients (13%) required a second operation (one dural repairand one implant removal). The clinical results were fair in two cases (13%) and no poor results were seen. At a mean follow-up of 6.5 years, 14 patients (93%) showed definite fusion signs.
According to the present data, we can conclude that in terms of fusion success, clinical outcome and complication rates, the use of posterior interbody cages alone is not as safe and effective for the management of one level degenerative disc disease or low-grade spondylolisthesis as the posterior pedicle screw instrumentation combined with two posterior cages or the stand-alone pedicle screw instrumentation.
