In 1973, Lombardi first reported a case of posterior epidural migration of a lumbar disc fragment and described the lesion as a “posterior rotation of annulus fibrosus” [13]. However, Lichtor has claimed that his paper is the first reported case of a lumbar disc herniation with migration to the posterior aspect of the caudal sac [12]. Dorsally migrated lumbar herniated nucleus pulposus is very rare entity but not uncommon and are reported as isolated case report and series. To our knowledge only less than 65 dorsally migrated discs has been described in literature till date [4,7,9].

Dorsally migrated disc herniation poses challenges from diagnosis to treatment methods [3,10] because it mimics with many other problems like epidural haematoma [18], tumor [1,5,7,8], facetal cyst [17,20], infection [18]. Diagnosis is made on the basis of clinical examination, imaging, labarotary tests as an exclusion. MRI is choice of imaging [2,6,14].

Treatment modality mostly being practiced for dorsally migrated lumbar disc at present is open surgey [1-3,5,6,10,12-14,16,17,19,20]. There is single case report of endoscopic removal11 of dorsally migrated lumbar disc but with laminotomy and ligamentum flavum excision and it is not percutaneous full endoscopic technique.

We treated this condition of dorsally migrated lumbar disc in presence of subtle instability in 60 years old man presented with subacute onset (2 weeks) of low back pain and right leg radiating pain with weakness of right great toe dorsiflexion by a full endoscopic technique called Percutaneous Full Endoscopic Ligamentum Flavum Splitting Interlaminar Approach sparing ligamentum flavum with successful outcome.

This technique not only addresses symptomatic pathology caused by dorsally migrated HNP but also simultaneously preserves motion segments. We want to share our case with this case report.

A 60 years old otherwise healthy gentle man presented after 2 weeks of gradual onset of symptoms with complaint of low back pain (LBP) associated with right leg pain and weakness of right great toe dorsiflexion without any significant history of trauma. He had no medical co morbidity He was thoroughly examined and investigated. His LBP and leg pain in Visual Analogue Scale (VAS) was 5/10 and 8/10 respectively. He had weakness of right toe dorsiflexion with grade 3/5 in Medical Research Council (MRC) grade. SLRT was 45 degrees on right side, 80 degrees on left side. X-rays revealed subtle instability in L4-5 in flexion and extension as subtle anterior wedging (Fig. 1A, 1B, 1C). CT revealed huge disc posteriorly (Fig. 1D, 1E). MRI showed a huge mass dorsal to dura at L4-5 level and it was compressing the dura (Fig. 1F, 1G). Working diagnosis of dorsally migrated disc with subtle instability was made on the basis of clinical presentation, imaging findings and laboratory tests. He was treated with Percutaneous Full Endoscopic Ligamentum Flavum Splitting Interlaminar Approach sparing ligamentum flavum (Fig. 2). A huge disc was removed. Final diagnosis of dorsally migrated disc was made with retrieval of disc material by endoscope. His pain resolved immediately after surgery. Weakness of right great toe also resolved gradually in 2 months. Postoperative X-ray showed no further instability (Fig. 3A,3B). Postoperative MRI revealed complete removal of disc with resolution of cord compression (Fig. 3C, 3D). No complication was noted related to this technique.