Review Question - QID 219586

The patient's MRI demonstrates a right-sided foraminal disk herniation at L3-L4, which would affect the exiting nerve root (L3) at this level. After exhausting non-invasive management, the next best step would be to perform a right-sided L3-L4 transforaminal injection (answer choice 3.)

Foraminal disk herniations occur less frequently than paracentral disk herniations, but when they occur, they are more frequently found at the L3-L4 level. Due to their proximity to the dorsal root ganglion, foraminal disk herniations tend to be more painful than paracentral ones and affect the exiting nerve root at the respective level. Contrary to facet pathology (i.e., facet cysts or osteophytic change), which more frequently causes lateral recess or subarticular stenosis affecting the traversing nerve root, foraminal stenosis results in radicular symptoms caused by exiting nerve root compression between the ventral overhang of the superior articular facet and a bulging disk. Treatment begins with a minimum of 3-6 months of non-invasive modalities and can be followed with steroid injections that are both diagnostic and therapeutic. If all non-operative modalities fail, decompressive surgery may be indicated.

Berra et al. reviewed the imaging, neurophysiology, and clinical features of far lateral disk herniations. The authors note that far lateral lumbar disc herniations (FLLDH) represent a separate category of disc pathology that includes both intraforaminal and extraforaminal lumbar disc herniations that are characterized by a unique clinical presentation, diagnostic, and treatment modalities when compared to the more frequently seen median and paramedian disc herniations. They conclude that neurophysiological tests are useful tools in the diagnosis and follow-up of FLLDH patients and that many go on to require surgical treatment due to pain that is often more severe than that seen in central disc herniations given more direct compression of the dorsal root ganglion.

Khan et al. reviewed the clinical presentation and postoperative outcomes of patients with lumbar far lateral herniated nucleus pulposus compared to those with central or paracentral herniations. The authors reviewed 100 patients and concluded that although patients with far lateral lumbar disc herniations present with worse preoperative outcome scores, they can expect similar symptom improvement to central or paracentral herniations following discectomy.

Abdullah et al. reviewed the clinical syndrome and special problems in diagnosis associated with extreme-lateral lumbar disk herniations. The authors reviewed 204 consecutive disk operations, of which 24 involved "extreme-lateral" disc herniations at the second, third, or fourth lumbar interspace. They found that the most common clinical syndrome was characterized by anterior thigh and leg pain, absent knee jerk, and sensory loss in the appropriate dermatome, but also by the absence of back pain, typical back signs, or positive Lasegue's sign. They concluded that reproducing pain and paresthesia by lateral bending to the side of the lesion is a reliable diagnostic sign.

Figures A-D represent right and left T1, midline T2, and axial T2-weighted MRI sequences of the lumbar spine, respectively, demonstrating a right-sided foraminal disk herniation at the L3-L4 level that is effacing the exiting L3 nerve root causing the patient's persistent L3 radicular symptoms.

Incorrect Answers:
Answer 1: Though a decompressive procedure may be indicated after exhausting non-operative treatment modalities, a laminotomy at this level is unlikely to appropriately address the root cause of this patient's symptoms, which is a foraminal disk herniation.
Answers 2 and 4: The patient's pathology is at the L3-L4 level and does not involve the facet joint; therefore, this treatment method would not appropriately address his pathology.
Answer 5: This patient's MRI does not demonstrate the presence of a facet cyst.