Background:

Intradural herniation (IDH) or transdural disc herniation is a rare presentation of lumbar disc disease. Preoperative imaging findings should be carefully and thoroughly interpreted. Although imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI) are readily available, a definitive diagnosis cannot be made based solely on these modalities. Operative procedures must be planned to prevent unexpected complications.

Case description:

A 67-year-old man presented with right lower extremity weakness and numbness with bowel and bladder involvement for 2 weeks, after falling from a standing position. MRI revealed a large herniated disc at L2-L3, which was suspected to be IDH. Posterior discectomy and interbody fusion were also performed. Intraoperative findings revealed no disc material in the epidural space or dural sac tenting. Dorsal midline durotomy was performed, and a mass-like lesion was found and resected. Subsequently, pathological analysis revealed disc tissue with evidence of moderate chronic inflammation and a focal increase in fibrosis. The patient was discharged without complications.

Results outcome:

Lower extremity strength improved to grades IV-V, accompanied by a return to normal bowel and bladder function within 1 month, without any wound complications. Lower extremity strength recovered fully to grade V, and the patient started walking independently within 6 months.

Conclusions:

A large disc herniation, suspected to be an IDH, should be thoroughly investigated by carefully reviewing MRI scans before proceeding with any surgical procedure to prevent unexpected situations. Nonetheless, preoperative imaging alone does not ensure a definitive diagnosis, and the differential diagnosis must include other mass-like lesions. Intraoperative findings and pathological reports are essential for definitive diagnosis of IDH.