How to differentiate and manage S1 radiculopathy versus Tarsal tunnel syndrome?

From the Guidelines

To differentiate and manage S1 radiculopathy versus tarsal tunnel syndrome, a careful clinical examination and targeted diagnostic testing are crucial, with a focus on MRI of the lumbosacral spine for suspected S1 radiculopathy and electrodiagnostic studies (EMG/NCS) for both conditions, as recommended by the most recent guidelines 1. When evaluating patients with symptoms of S1 radiculopathy or tarsal tunnel syndrome, it is essential to consider the distinct symptom patterns and anatomical origins of each condition. S1 radiculopathy typically presents with pain radiating from the lower back down the posterior leg to the lateral foot, weakness in plantar flexion, diminished Achilles reflex, and positive straight leg raise test. In contrast, tarsal tunnel syndrome causes burning pain, numbness, and tingling primarily in the plantar aspect of the foot, worsening with prolonged standing or walking, with symptoms reproduced by tapping over the tarsal tunnel (positive Tinel's sign).

Diagnostic Approach

• MRI of the lumbosacral spine is the initial imaging modality of choice for suspected S1 radiculopathy, as it accurately depicts lumbar pathology, including disc degeneration, and the thecal sac and neural structures 1.
• Electrodiagnostic studies (EMG/NCS) are useful for both conditions, as they can help identify nerve root compression or abnormal intraneural signal in the nerves 1.
• A careful clinical examination, including a thorough medical history and physical examination, is essential to differentiate between S1 radiculopathy and tarsal tunnel syndrome.

Management

• Initial management for both conditions includes NSAIDs (ibuprofen 400-800mg three times daily or naproxen 500mg twice daily) for 2-3 weeks and activity modification.
• S1 radiculopathy may benefit from physical therapy focusing on lumbar stabilization exercises, while tarsal tunnel syndrome responds to foot orthotics, proper footwear, and ankle bracing.
• For persistent S1 radiculopathy, consider epidural steroid injections, while tarsal tunnel syndrome may require corticosteroid injection into the tarsal tunnel.
• Surgery is reserved for cases with progressive neurological deficits, significant pain despite conservative treatment, or confirmed compression requiring decompression, as recommended by the British Pain Society 1.

From the Research

Differentiating S1 Radiculopathy and Tarsal Tunnel Syndrome

• S1 radiculopathy and Tarsal Tunnel Syndrome (TTS) can present with similar symptoms, making diagnosis challenging 2.
• TTS is a compression neuropathy of the posterior tibial nerve, which can cause pain, numbness, tingling, and weakness in the foot and ankle 3, 4.
• S1 radiculopathy, on the other hand, is a condition that affects the S1 nerve root, causing symptoms such as pain, numbness, and weakness in the lower back, buttock, and leg 2.

Clinical Presentation

• The clinical presentation of TTS can vary, but common symptoms include pain, numbness, tingling, and weakness in the foot and ankle 3, 4.
• S1 radiculopathy can also present with similar symptoms, including pain, numbness, and weakness in the lower back, buttock, and leg 2.
• A thorough clinical evaluation, including a physical examination and medical history, is necessary to differentiate between the two conditions 4, 2.

Diagnostic Tests

• Diagnostic tests, such as nerve conduction studies (NCS) and electromyography (EMG), can help diagnose TTS and S1 radiculopathy 4, 2.
• Imaging tests, such as MRI or CT scans, may also be used to rule out other conditions that can cause similar symptoms 4.
• The Tinel's sign, a clinical test that involves tapping the nerve to elicit symptoms, can be positive in patients with TTS 4, 2.

Management

• Conservative management, including activity modification, pain relief medications, and physical therapy, can be effective in treating TTS and S1 radiculopathy 3, 4.
• Surgical treatment, such as decompression of the posterior tibial nerve, may be necessary in some cases of TTS 4, 5.
• A structured approach to managing patients with TTS and S1 radiculopathy, based on empirical evidence, is necessary to improve patient outcomes 6.

Coexistence of TTS and S1 Radiculopathy

• The prevalence of TTS in patients with S1 radiculopathy is significant, with one study finding that 4.8% of patients with lumbosacral radiculopathy also had TTS 2.
• The coexistence of TTS and S1 radiculopathy can make diagnosis and management more challenging, and a thorough clinical evaluation is necessary to identify both conditions 2.