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Tarsal tunnel syndrome is a relatively rare mononeuropathy of the lower extremities that can be difficult to diagnose. Clinical evaluation, electroneurography (ENG), and electromyography (EMG) are used to diagnose this posterior tibial nerve neuropathy, allowing for more accurate treatment and management plans to help alleviate the patient’s symptoms. This activity will briefly discuss the etiology and pathophysiology of tarsal tunnel syndrome and describe how ENG and EMG can be used to identify this condition. Objectives: Assess the diagnostic findings of tarsal tunnel syndrome found on ENG and EMG. Identify common pitfalls when conducting ENG of the tibial nerve and its branches, and EMG of the intrinsic foot muscles. Determine the appropriate recording and stimulation sites of the medial and lateral plantar nerves. Communicate the importance of communicating the findings of the electrophysiological study with the interprofessional team to better enhance patient outcomes. Access free multiple choice questions on this topic.

Often, it is difficult to fully elucidate a neuromuscular diagnosis with history and physical examination alone. Furthermore, many neuromuscular diagnoses cannot be identified on an MRI or CT scan and thus require an alternate modality to identify—this is the role of the electrodiagnosis techniques: Electroneurography (ENG) and electromyography (EMG). Specifically, ENG and EMG are useful in identifying peripheral neuropathies caused by tibial nerve compression. Neuropathy of the posterior tibial nerve is a relatively rare condition that causes foot and ankle pain, paresthesia, and even weakness of the intrinsic foot muscles. When this neuropathy occurs in the tarsal tunnel, it is known as tarsal tunnel syndrome. External compression by ill-fitting footwear or tight plaster casts most frequently causes this condition. Other causes are posttraumatic fibrosis and acute trauma (such as those from sprains, strains, and fractures). Still, they can also result from lipomas, cysts, tumors, soft tissue infections, and inflammatory arthropathies. A true entrapment from a thickened flexor retinaculum is rare.[1][2][3] Electromyography can identify the specific muscles affected by a nerve lesion. If a nerve lesion localizes to the tarsal tunnel, the practitioner must determine the cause of the compression.[4]

In many instances, the disease progression of this mononeuropathy is reversible if addressed early on. Efficient interdisciplinary and interprofessional communication is crucial to treating patients with neuropathy. Appropriate referral by the first medical professional encountering a patient’s complaint can be the difference between an acute disease process and a chronic complication. By identifying the location of the nerve lesion to the tibial nerve at the level of the medial malleolus, the EMG practitioner can address the causative agent. Initially, conservative measures require clinical attention, including footwear changes, physical therapy, and anti-inflammatory medications. Through effective interdisciplinary and interprofessional communication, the patient’s medical providers can monitor the patient’s progress. If the patient does not demonstrate adequate progress, surgical intervention is needed. Collaboration and shared decision-making ultimately allow the patient to have the best possible outcome. The earlier the signs and symptoms of neuropathy are identified and the electrodiagnosis test performed, the better the prognosis and outcome.[12][4]

Depending on the concrete circumstances, a collaboration between the clinicians to hand in technical material, ensure the correct humidity of electrodes and alcohol swabs, and prepare the patient is of great help.