Most ankle sprains are lateral, affecting the anterior talofibular, calcaneofibular and posterior talofibular ligaments. Other injuries include medial ankle sprains affecting the deltoid ligament, trauma to the Achilles and peroneal tendons, tarsal tunnel syndrome, fractures, syndesmotic sprains, synovial impingement and chronic instability. Criteria for radiographic evaluation include inability to bear weight initially or when examined, and tenderness over the medial or lateral malleolus. Accurate diagnosis is critical for appropriate treatment and minimizing functional disability. Pallidotomy and thalamotomy are the stereotactic procedures most commonly performed in patients who fail to obtain satisfactory relief of their symptoms despite optimal medical therapy.
Small lesions disrupt the abnormal activity of basal ganglia circuitry.
Other options currently being studied include chronic high-frequency stimulation and transplantation of fetal mesencephalic tissue. Chronic thalamic stimulation, involving permanent implantation of a deep brain electrode and a pulse generator, effectively controls contralateral tremor. Fetal nigral transplantation, which is still an experimental procedure, has the potential of restoring lost nigrostriatal pathway. The choice of treatment depends on the severity of the symptoms and their response, or lack of response, to pharmacologic therapy. With appropriate selection criteria, functional and symptomatic improvement can be achieved in most patients with Parkinson's disease who are treated with neurosurgical procedures.