Postoperative bone graft migration into the thecal sac and shifting down to the lower level after an endoscopic lumbar interbody fusion: a case report

BACKGROUND: Postoperative bone graft migration (PBGM) is a fairly rare spinal postoperative complication. Its occurrence after endoscopic surgery has rarely been reported in the literature so far. This is a case report of a 52-year-old male occurring PBGM into the thecal sac in the 8th days after an endoscopic lumbar interbody fusion (ELIF), which can make surgeons more minded with such serious rare complication after BGM. CASE PRESENTATION: A 52-year-old male patient, underwent a L4-5 ELIF, presented with an acute radiculopathy on right leg and urinary incontinence in the 8(th) postoperative day. An emergency lumbar Computed Tomography(CT scan) and Magnetic Resonance Imaging (MRI) demonstrated bone graft migration into the thecal sac at the L4-5 level, and shifting down to the lower level. The revision surgery was performed at once successfully. Finally, the patient got well managed before discharge. CONCLUSION: Supported by this case report, we believe that PBGM into the thecal sac is a rare but horrible complication of ELIF. However, too much volume of bone graft and its posterior placement are more prone to developing this complication. Finally, we are not sure that the outcome presented in this study will be repeated in future cases. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12891-023-06247-7.