A case of late dislocation of a disc spacer L5/S1 with perforation of the sigmoid colon and transanal passage 4 years after implantation is reported. The objective is to describe an uncommon complication of anterior endoscopic spondylodesis L5/S1. To our knowledge, this is the first report on this rare complication. A 39-year-old patient suffering from a spondylolisthesis L5/S1 (Meyerding grade 2) with bilateral lysis L5 was operated with posterior instrumentation L5/S1 and anterior endoscopic insertion of two disc spacers. 4 years after surgery the patient noticed one of the spacers in the toilet. Radiographic examination of the colon with contrast dye revealed a perforation at the distal sigmoid colon. At the lumbosacral junction there was a bony defect at the site of the absent spacer and an anterior dislocation of the second spacer. A partial resection of the colon at the perforation site with end-to-end anastomosis was performed. The second spacer was removed, and the defect was packed with autologous cancellous bone and local antibiotics. The further course was uneventful. 2 weeks postoperatively the patient was discharged without signs of infection. The radiographic examination after 6 months showed healing of the bone graft with bony fusion L5/S1. In case of incomplete or absent bony fusion the dislocation of intradiscal spacers may arise even years after the primary surgery. In consequence periodical radiographic examinations of spinal instrumentations are recommended until complete bony fusion occurred. Unclear abdominal symptoms following anterior spine surgery require immediate examination.
