Figure 1. Sagittal MRI of the lumbar spine shows a large left-sided disc herniation at the L4-L5 level.
Figure 2. Axial view of the disc herniation on the left side at L4-L5.
A 55-year-old man presents to the office with severe left-sided leg pain that has been present for 3 months. The patient notes that he was doing a lot of yard work 4 months ago, which included reaching down to the ground. The next few weeks following his yard clean-up, he had significant lower back pain. After a few weeks, the pain transitioned to severe left leg pain. On physical examination, the patient has weakness (2/5 strength) to his extensor hallucis longus muscle that, according to a previous visit, has been stable for 6 weeks. Sagittal and axial magnetic resonance imaging (MRI) of the lumbar spine show a large left-sided disc herniation at the L4-L5 level (Figures 1 and 2).
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The patient is presenting with an acute left-sided L4-L5 disc herniation causing L5 radiculopathy with extensor hallucis longus weakness. Conservative treatment is initially recommended for acute lumbar radiculopathy as 90% of patients will get better within 3 months. For patients with unrelenting pain beyond 3 months, surgery provides substantial and more rapid pain relief than nonsurgical care.
Surgery is indicated if pain lasts for greater than 3 months or motor weakness progressively worsens. Stable nonprogressive motor weakness resolves similarly for both surgical and nonsurgical management.1,2
For patients with severe motor deficits, there is a concern that even after surgery muscle strength may not improve. Postacchini et al found that after microdiscectomy, a full recovery of muscle strength was observed in 84% of patients who had a mild preoperative deficit and 61% of those with a severe deficit.1
In general, the severity of preoperative motor weakness correlates with the degree of motor strength recovered after surgery. The location of the disc herniation and degree of compression to the nerve root affects motor weakness to a greater degree than the actual size of the herniation. Severe and rapid nerve root compression causes more damage to the neural tissue than mild or slow compression.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopaedics for Physician Assistants.
1. Postacchini F, Giannicola G, Cinotti G. Recovery of motor deficits after microdiscectomy for lumbar disc herniation. J Bone Joint Surg Br. 2002;84(7):1040-1045. doi:10.1302/0301-620x.84b7.129482
2. Akagi R, Aoki Y, Ikeda Y, et al. Comparison of early and late surgical intervention for lumbar disc herniation: is earlier better? J Orthop Sci. 2010;15(3):294-298. doi:10.1007/s00776-010-1457-1