[Sciatica and occult sacral meningocele].

The authors present the case of a 43-years-old man who had suffered from back pain for 7 to 8 years followed by sciatic. X-rays showed an abnormal sacral cavity extending from S1 to S3. Wtih the suspicion of an occult sacral meningocoele, Dimer X radiculography showed a cystic formation at S2 which only partially filled the sacral cavity. There was also an L5-S1 disc protrusion. At operation, after exploration of the roots on both sides, it was possible to remove a disc herniation at L5-S1 on the right. Laminectomy of S1 and opening of the posterior wall of the sacral canal at S2 and S3 revealed a large cyst of epidural location, touching both S1 roots superiorly and situated behind the communicating cystic cavity seen at radiculography. Histological examination of the sacral cyst showed it to be a dura mater structure, in fact anon-communicating meningocoele.