The Effect of tDCS in the Preoperative Period of Hallux Valgus Surgical Treatment

This is a clinical trial that intend to determine if transcranial direct current stimulation (tDCS) is effective in the treatment of postoperative pain and in the anxiety level in the preoperative period of hallux valgus surgical treatment

Introduction: Forefoot deformities are important cause of feet pain and discomfort and affect around 80% of general population, predominantly in female population. Among teenagers and adults´ common forefoot deformities is hallux valgus. To achieve the deformity heal, surgical treatment is needed. The transcranial direct current stimulation (tDCS) is a non invasive technic, that aims for the central nervous system modulation for pain control, which can become a therapeutic option for postoperative pain. Experimental studies have shown that tDCS has reverted the hyperalgesia induced by chronic stress and articular inflammatory pain, has reduced total knee arthroplasty postoperative opioid consumption and a single 20 minutes session has shown reduction in endoscopic procedures opioid consumption, safety and minimal adverse effects. However, the tDCS effect in preoperative hyperalgesia has not been explored yet in sensitized patients, neither in anxiety and postoperative rehabilitation of patients submitted to hallux valgus surgical correction. In this study, it was chosen to use tDCS to stimulate cerebral cortex due to its efficacy in painful syndromes, for being a non invasive, low cost and easy-to-apply technic in comparison to other neurostimulation technics and especially, for its potential to counter-regulate the mal adaptive neuroplastic alterations associated to chronic pain. Objective: to evaluate the effect of tDCS compared to tDCS-sham in the pain control (visual analog scale score, pain threshold and the descendent modulator system), perioperative anxiety, postoperative analgesic drug consumption and in the rehabilitation of patients with arthralgia of the first metatarsophalangeal articulation submitted to hallux valgus surgical correction. Method: it is a randomized, blinded, placebo-sham controlled clinical trial which includes 40 female patients, between 18 and 70 years old, candidates to hallux valgus surgical treatment by combined Chevron + Akin osteotomy due to arthralgia of the first metatarsophalangeal articulation. The patients will be randomized and divided into two groups that will be treated with two tDCS or tDCS-sham sessions of 20 minutes each in preoperative period. Expected results: This study will evaluate the effect of tDCS as a treatment option to postoperative pain and perioperative anxiety of patients submitted to hallux valgus surgical correction. In case of proven efficacy, this technic can become a low cost, easy access, safe and effective treatment option for these patients.

Eligibility Criteria:
Inclusion Criteria:

* indication of hallux valgus surgical treatment because of arthralgia of the first metatarsophalangeal joint,
* capability of writing and understanding the Portuguese language

Exclusion Criteria:

* diabetic neuropathy,
* history of intense or frequent headache,
* chronic dermatologic disease,
* previous adverse effects to treatment with tDCS, seizures,
* severe cranial trauma with alteration of the cranial anatomy,
* metallic intracranial implants or pacemaker,
* non-compensated psychiatric disease,
* non-collaborative patients,
* history of neurologic,
* oncologic disease,
* heart, renal or hepatic failure.