Exploration of the Extraperitoneal Approach for Single-Level Anterior Lumbar Interbody Fusion: Imaging, Anatomical and Clinical Research.

Background: To explore extraperitoneal approach as an optimal option for reducing peritoneal disruption at a single-level disc in anterior lumbar interbody fusion (ALIF). Methods: First, abdominal axial CT images obtained from 111 patients were observed to evaluate the distribution of extraperitoneal fat at L2-S1 and measure the lateral distances between the midline and the lateral borders of the rectus and the extraperitoneal fat for each disc level. Second, eight embalmed corpses were dissected along the lateral border of the rectus to expose the peritoneum, which was then separated laterally and medially to evaluate the distribution of fat and peritoneum adhesion. Finally, a total of 58 patients were selected for ALIF. For L2-L4 discs and L4-S1, the pararectus approach and the paramedian approach were utilized, respectively. Results: Extraperitoneal fat was observed behind the rectus at the L5-S1 and the lateral distance between the fat and midline and the lateral border of the rectus gradually decreased on both sides of L2-5. On the cranial side of the arcuate line, it was easier to separate the peritoneum outward along the lateral edge of the rectus. When bluntly dissected medially, the peritoneum was closely adhered to abdominal wall. No complications such as peritoneal damage, retroperitoneal hematoma and neurological complications occurred in 58 patients undergoing the aforementioned surgical methods. Conclusions: For L4-S1, the paramedian approach is the optimal technique to expose the disc, whereas the pararectus approach is the feasible surgical method at L2-4.