Abstract

The spinal instability represents a specific state of a structure in which an addition of small load results in an excessively large displacement in an unpredictable or erratic manner. In contrast, an abnormally large, but in the right manner, segmental motion can be defined by the term “hypermobility”. Spinal instability can be found in various conditions, such as after trauma or excessive surgical removal of supporting structures or advanced degenerative conditions or malformations. A very good anamnestic investigation of the patient must be made. Dynamic flexion/extension and lateral bend can show the abnormal spine motion. Plain radiographic findings, that suggest segmental instability, include disc space narrowing, osteophytes, spondylo-deformities and spondylolisthesis. Spinal fusion has been a commonly accepted procedure in spine surgery. The posterior approach (P.L.I.F.) is carried out by the removal of the posterior part of the lumbar vertebra. Disadvantages of the posterior lumbar interbody fusion include the possibility of extrusion of the graft, secondary spinal instability, dural tears and scarring of the anterior portion of the dural sac. The anterior approach (A.L.I.F.) may be carried out transperitoneally or retroperitoneally. Disadvantages of anterior lumbar interbody fusion include the risk of abdominal adhesions and incisional hernias, particularly in the transperitoneal approach; in males also carries the risk of impotence or retrograde ejaculation. By percutaneous lumbar posterolateral and parapedicular approach it is possible to stabilize the lumbar spine using cages (B-Twin) and calcium phosphate bone graft substitute (pure beta-tricalcium phosphate), when stand alone solution is indicated. With this minimally invasive spinal technique the trauma for the patient in the surgical area is minimised and consequently complications are very uncommon. In our experience , if an interbody fusion is being considered, we have found percutaneous interbody fusion to be easy technique, more reliable, and associated with fewer complications than open traditional approaches. This study was carried out from October 2002 to February 2007. In our follow-up we had a success rate was more than ninety percent. In this study period there were neither incidents during surgery, nor significant complications following these operations. Average time to perform a standard lumbar fusion by this procedure was about 60 minutes. Comprehensive training in this kind of surgery is necessary before performing operations. We think that continued development and improvement of instruments, longer followup periods and a greater number of patients treated by this technique, will further confirm this percutaneous surgical approach.