The authors report a case of rectal injury, rectocutaneous fistula, and pseudarthrosis after a TranS1 axial lumbar interbody fusion (AxiaLIF) L5-S1 fixation. The TranS1 AxiaLIF procedure is a percutaneous minimally invasive approach to transsacral fusion of the L4-S1 vertebral levels. It is gaining popularity due to the ease of access to the sacrum through the presacral space, which is relatively free from intraabdominal and neurovascular structures. This 35-year-old man had undergone the procedure for the treatment of degenerative disc disease. The patient subsequently presented with fever, syncope, and foul-smelling gas and bloody drainage from the surgical site. A CT fistulagram and flexible sigmoidoscopy showed evidence of rectocutaneous fistula, which was managed with intravenous antibiotic therapy and bowel rest with total parenteral nutrition. Subsequent studies performed 6 months postoperatively revealed evidence of pseudarthrosis. The patient's rectocutaneous fistula symptoms gradually subsided, but his preoperative back pain recurred prompting a revision of his L5-S1 spinal fusion.