Lumbar disc herniation distal to the lumbar intervertebral foramen, considered for some authors a type of extreme lateral lumbar disc herniation.

Its particular anatomical site makes its clinical and neurologic features completely different from those of posteromedial and posterolateral disk herniations. Prior to the advent of computerized tomography, only diskography was capable of preoperatively identifying this rare disease.

Santini et al., present 5 cases of extraforaminal disk herniation, the clinical and tomographic diagnosis of which was confirmed at surgery. All patients had severe motor deficit and reported sciatica as prevalent over low back pain. The herniated disk was L4-5 in 2 cases and L5-S1 in 3 cases. The CT scan suggested disk protrusion in 2 cases, extrusion in 2 cases, and sequestration in 1 case. Four of these findings were confirmed intraoperatively. Diskectomy was done after hemilaminectomy and partial or total facetectomy. The clinical result was excellent in 2 cases and good in 3 cases after an average follow-up of 10 months. The use of CT scan as part of the routine diagnostic procedure in patients with radicular pain has lowered the number of cases which the surgical findings were inexplicably negative for disk herniation without having to resort to more complex and invasive diagnostic techniques such as myelo-CT and disk-CT. Moreover, preliminary tomographic localization of the extraforaminal disk herniation makes it possible to operate on the affected level using more conservative techniques. In any case, thorough clinical examination is essential for both correct interpretation of the CT scan and appropriate choice of treatment ¹⁾.

A 33-year-old man presented with moderate low back pain and L5 radiculopathy that progressed to severe paresis of L-5. On initial imaging, a corresponding spinal lesion was overlooked. Further CT and contrast-enhanced MRI demonstrated a presacral mass along the L-5 root far extraforaminally. A herniated disc was suspected, but with standard imaging a schwannoma could not be ruled out. The presacral L-5 root was explored via a microsurgical lateral extraforaminal transmuscular approach. To the best of the authors' knowledge, there have been no reports of sequestered extraforaminal lumbosacral disc herniations that herniated into the presacral region.