From the Guidelines
L4 nerve leg pain after running is most likely caused by compression or irritation of the L4 nerve root, which can result from several conditions, including a herniated disc, spinal stenosis, or degenerative disc disease, as supported by the American College of Physicians and the American Pain Society guidelines 1. The pain typically manifests as discomfort radiating from the lower back down the front or side of the thigh, sometimes extending to the inner part of the lower leg.
- The most common causes of L4 nerve leg pain include:
- Herniated disc at the L3-L4 level
- Spinal stenosis (narrowing of the spinal canal)
- Degenerative disc disease
- Running, which involves repetitive impact and spinal loading, can aggravate these conditions by increasing pressure on the nerve root. Treatment usually begins with:
- Rest
- Over-the-counter anti-inflammatory medications like ibuprofen (400-800mg every 6-8 hours with food) or naproxen (220-440mg twice daily with food) for 1-2 weeks
- Gentle stretching exercises focusing on the lower back and hamstrings Physical therapy can help strengthen core and back muscles to provide better spinal support. For immediate relief after running, applying ice to the lower back for 15-20 minutes can reduce inflammation. If pain persists beyond 2-3 weeks, worsens, or is accompanied by weakness or numbness, medical evaluation is necessary as prescription medications, epidural steroid injections, or in rare cases, surgical intervention might be required, as suggested by recent guidelines 1.
From the Research
Causes of L4 Nerve Leg Pain After Running
- L4 nerve leg pain after running can be caused by various factors, including lumbar radiculopathy or spinal stenosis 2
- Running can exacerbate existing conditions, such as degenerative lumbar stenosis and/or spondylolisthesis, leading to L4 nerve leg pain 3
- The L4 nerve root can be irritated or compressed, resulting in pain, numbness, or tingling in the leg 4
Risk Factors and Complications
- Lumbar radiculopathy can be presented as low back pain and radiating pain, and transforaminal epidural steroid injection (TFESI) has been used to treat radicular pain 5
- However, there are potential risks associated with the lateral lumbar interbody fusion (LLIF) approach, including vascular or visceral injury, thigh dysesthesias, and lumbar plexus injury 3
- Careful patient selection, meticulous use of real-time neuromonitoring, and an understanding of the anatomic location of the lumbar plexus to the working corridor are critical to success 3
Treatment Options
- Conservative management of lumbar radiculopathy is the first treatment option, and it may include providing patients with information about the condition, individualized physical activity, and directional preference exercises, supported with NSAIDs 6
- In the sub-acute stage, strength training and neurodynamic mobilization could be added, and transforaminal/epidural injections could be considered 6
- Gabapentinoids, including pregabalin and gabapentin, can be administered to relieve remnant pain after transforaminal epidural steroid injection 5