Bowel Injury and Insidious Pneumoperitoneum after Lateral Lumbar Interbody Fusion

Study design: Retrospective review of prospectively collected cases. Purpose: To report bowel injury cases and determine the incidence and risk factors of insidious pneumoperitoneum after lateral lumbar interbody fusion (LLIF). Overview of literature: Minimally invasive LLIF is considered a safe surgical approach with a low risk of complications. Visceral injury after LLIF is rare and, to our knowledge, no studies on pneumoperitoneum after LLIF have been performed. Bowel injury is a catastrophic complication, but the clinical signs may not be apparent. After we encountered two cases of bowel injury after LLIF, we decided to perform computed tomography of the abdomen and pelvis (APCT) after surgery for all patients who underwent LLIF. Methods: A total of 90 patients underwent APCT within 48 hours of surgery. Medical records were reviewed to determine each patient's age, sex, body mass index, medical and surgical histories, characteristics of LLIF procedures, and subjective symptoms and abnormal findings in the physical examination related to acute abdomen after surgery. Various parameters were compared between patients with and without pneumoperitoneum. Results: Bowel injuries were identified in the first two patients and five patients (5.5%) were diagnosed with pneumoperitoneum only on APCT. We found that the greater the number of fused segments, the higher the incidence of postoperative bowel injury and/or pneumoperitoneum. The incidence was significantly high when the L2-3 level was included in the LLIF surgery. Conclusions: Pneumoperitoneum after LLIF indicates damage to the peritoneum and the presence of bowel injury that may lead to peritonitis. However, it is difficult to distinguish pneumoperitoneum and/or bowel injury from general abdominal pain after surgery because patients may present with a wide range of symptoms. We recommend that APCT be routinely performed after LLIF surgery in order to promptly identify pneumoperitoneum and bowel injury.