From the Guidelines
Far lateral disc herniation at the L5-S1 level typically presents with symptoms of nerve root irritation, including pain, numbness, and weakness in the lower extremity.
Common Symptoms
- Pain in the lower back and leg, particularly in the S1 nerve root distribution, which includes the posterior thigh, calf, and foot 1
- Numbness or tingling in the foot or ankle
- Weakness in the muscles of the lower extremity, particularly those innervated by the S1 nerve root, such as the gastrocnemius and soleus muscles
- Decreased ankle reflex, which can be assessed through a neurologic examination 1
Diagnostic Evaluation
A focused examination, including straight-leg-raise testing and a neurologic examination, should be performed to assess the presence and severity of nerve root dysfunction 1. MRI is the preferred imaging modality for evaluating patients with persistent back and leg pain who are potential candidates for invasive interventions 1. It is essential to note that findings on MRI or CT, such as bulging disc without nerve root impingement, are often nonspecific 1. In patients with suspected far lateral disc herniation at the L5-S1 level, a thorough diagnostic evaluation, including a physical examination and imaging studies, is necessary to confirm the diagnosis and guide treatment 1.
From the Research
Symptoms of Far Lateral Disc Herniation at L5-S1 Level
The symptoms of a far lateral disc herniation at the L5-S1 level can be summarized as follows:
- Severe radicular pain accompanied by positive mechanical signs, such as Laségue and reverse Laségue (femoral stretch test) maneuvers 2
- Neurological deficits, including motor, reflex, and sensory findings, which are seen in over 75% of cases 2
- Lower back pain, radicular pain, hypoesthesia, and muscle weakness on the contralateral side alone, as reported in a case series of 11 patients with lumbar disc herniation and contralateral symptoms 3
- Anterolateral thigh pain, dysesthesia resulting from nerve root or dorsal root ganglion (DRG) compression in the foraminal or extraforaminal region, as described in three operated cases of far lateral lumbar disc herniation 4
- Gait disturbance due to severe leg pain, antero-lateral thigh pain or dysesthesia, which are characteristic of far lateral lumbar disc herniation 4
Clinical Features and Radiographical Findings
The clinical features and radiographical findings of far lateral disc herniation at the L5-S1 level include:
- Characteristic clinical features, such as severe radicular pain and neurological deficits 2
- Radiographical findings, such as a foraminal or extraforaminal herniated disc, which can be detected using high-resolution CT or MRI 4, 5
- Detailed anatomical relationships between the herniated disc and nerve root or DRG in the foraminal and extraforaminal regions, which can be visualized using MRI 4
- Normal myelography and potentially negative high-quality magnetic resonance images, making high-resolution computerized tomography (CT) and CT-discography useful diagnostic tools 5