The patient was then referred to our department. A complete physical and neurological examination was made. The patient mainly complained of lower abdominal pain with overflow incontinence, sciatic pain in both legs with a predominance on the left side, and mechanical lower lumbar pain. The neurological examination showed no motor deficits at lower extremities with preservation of tone and reflexes. Sensitivity was patchy in both legs around L5 and S1 dermatomes, but resulted quite inconsistent. An MRI (Figure \ref{fig:FIGURE_1}) showed an anterior pre-sacral cyst eroding the anterior wall of S2 and S3, herniating through an anterior sacral defect. The collection measured 10x9cm, exerting compression on the rectum and the bladder in a significant way.

Due to these pelvic symptoms and the presence of a growing mass, a new surgical procedure consisting in a posterior sacral laminectomy and ligation of the meningocele cyst was proposed. We believe this approach is appropriate to get a correct exposure of the cyst neck.