Lateral Retroperitoneal Approach Using the Bak Interbody Fusion Cage – Early Surgical Experience

Interbody fusion cages used in conjunction with autogenous bone graft have been shown to be effective in treating internal disc disruption, low grade spondylolisthesis, and degenerative disc disease. Under FDA-IDE, placement of a BAK cage using a laparoscopic, transperitoneal approach has shown promising results at L4-5 and/or L5-S1, accessing the anterior disc space is L4-5 requires the mobilization of great vessels, making a general surgeon a necessity for the procedure. This study presents the preliminary results of a new surgical approach – a less invasive, lateral, retroperitoneal disc cage insertion for L4-5 and higher lumbar interbody fusions. This technique was used in four patients from September 1996 to February 1997, one patient had L4-5 Grade 1 degenerative spondylolisthesis, and the other three had discogenic low back pain. Unfortunately, this patient was found postoperatively to have left femoral nerve neuropraxia with ipsilateral quadriceps weakness. The fourth lumbar nerve root may have been injured by the forceful retraction needed to mobilize a tight psoas muscle with the use of a tooth-bladed Hibbs retractor. The procedures of the other cases were performed rather smoothly after changing the smooth-bladed retractor. Anatomically, there are no great vessels located along the lateral side of the vertebral bodies. Biomechanically, according to our previous studies, a single, lateral-placed BAK achieved level of stiffness similar to traditional anteroposterior placement using two cages. Our early experience with this technique, as presented in this study, confirmed its advantages in terms of effectiveness, ease, and lower morbidity for anterior interbody fusion of degenerative lumbar lesions above L5-S1.