Review Question - QID 211784

A far lateral disc herniation at the L5-S1 level will affect the exiting nerve root. Therefore this will cause symptoms in the L5 distribution. The most correct answer is 3) hip Abduction.

Disc herniations can be classified as either central, paracentral or far lateral. Most lumbar disc herniations are paracentral and therefore affect the traversing nerve root. In this case, a paracentral disc herniation at L5-S1 would cause weakness in ankle plantarflexion (S1). A far lateral disc herniation affects the exiting nerve root as it goes underneath the pedicle and exits the foramen. Other L5 nerve root physical exam findings would include weakness with great toe extension.

Millhouse et. al. review the surgical technique for a paracentral disc herniation. They note that early surgical intervention is indicated for patients with cauda equina syndrome, deteriorating neurological exam or debilitating pain. They conclude that for a far lateral disc herniation that a Wiltse approach may be utilized.

Soliman et. al. evaluated 54 patients that underwent limited discectomy (removal of fragment only). They report that at 7 years follow up there was an 11% reoperation rate for revision discectomy and 6% required conversion to lumbar fusion. They conclude that there was no difference between extruded and contained fragments.

Figure 1 depicts a left far lateral disc herniation, which compresses the L5 nerve root.

Incorrect answers:
Answer 1: Hip flexion is primarily a function of the L2 and L3 nerve roots.
Answer 2: Hip adduction is primarily a function of the L3 and L4 nerve roots.
Answer 4: Knee extension is primarily a function of the L4 nerve root.
Answer 5: Ankle plantarflexion is primarily a function of the S1 nerve root.